MULTIDISCIPLINARY ABSTRACTS

© 2001 Blackwell Science Inc., 1530-7085/01/$15.00Pain Practice, Volume 1, Number 4, 2001 370–385

phine with a femoral nerve block post-operatively. A futurestudy employing preoperative femoral nerve block with orwithout use of intraarticular morphine might be interesting tosee on arthroscopic ACL repairs to obtain adequate analgesiaas the authors suggested.

Anesthesia (2)

Li-Kai Wang, Han-Ping Chen, Pei-Jung Chang, Fu-Chi Kang,Yu-Chuan Tsai:

Axillary brachial plexus block with patientcontrolled analgesia for complex regional pain syndrome typeI: a case report. (National Cheng Kung University, Tainan,Taiwan)

Reg Anesth Pain Med

2001;26:68–71.

A 32-year-old man who suffered from complex regional painsyndrome type I (CRPS I) of the right upper limb after surgicalrelease of carpal tunnel syndrome of the right hand is the sub-ject of this case report. Symptoms and signs over the righthand were alleviated under rehabilitation and conventionalpharmacological management, but severe painful swelling ofthe right wrist persisted. Axillary brachial plexus block (BPB)with patient controlled analgesia (PCA) was performed on the32

nd

postoperative day, which soon resulted in significant re-duction of pain with gradual improvement of function of theright wrist. Conclude that axillary BPB with PCA may providepatients with CRPS I of the upper limb a feasible and effectivetreatment.

Anesthesia (3)

J. Richardson, P. McGurgan, S. Cheema, R. Prasad, S. Gupta:

Spinal endoscopy in chronic low back pain with radiculopa-thy. (Bradford Royal Infirmary, Bradford, United Kingdom)

Anaesthesia

2001;56:454–460.

All 38 patients listed for day-case spinal endoscopy over a 12-month period, who had chronic severe low back pain with aradiculopathic element, were studied. The mean pain durationbefore treatment was 10.9 years and 50% had failed back sur-gery syndrome. In all patients in whom treatment was com-pleted (n

�

34), the pain-generating nerve roots were locatedthrough symptom interaction with the patient. All had epidu-ral scar tissue, 14 (41%) having dense adhesion. Mobilizationof adhesions around the nerve root was performed so that apocket was formed for the subsequent placement of bupiv-acaine, Depomedrone, and clonidine. No intra-operative com-plications occurred and side effects were minimal. Follow-upover a 12-month period showed statistically significant reduc-tions in pain scores and disability. Spinal endoscopy may bethe diagnostic method of choice for epidural fibrosis. It hassubstantial therapeutic and research potential. Prospectiverandomized studies are required.

Anesthesia (1)

Eric C. McCarthy, Kurt P. Spindler, Ed Tingstad, Yu Shyr,Michael Higgins:

Does intraarticular morphine improve paincontrol with femoral nerve block after anterior cruciate liga-ment reconstruction? (Vanderbilt University Medical Center,Nashville, TN)

American Journal of Sports Medicine

2001;29:327–332.

In a prospective, randomized, double-blinded manner, the au-thors of this study compared the effects of a preoperative in-traarticular injection of morphine (5 mg) or a placebo, com-bined with a postoperative femoral nerve block, on postoperativepain. Sixty-two patients underwent an arthroscopically as-sisted anterior cruciate ligament reconstruction using patellartendon autograft under general anesthesia. No statistical dif-ference between the 2 groups was evident in terms of age, sex,weight, operative time, volume of bupivacaine received withthe femoral nerve block, or tourniquet use or tourniquet time.A comparison of the visual analog pain scale scores revealedno statistical difference between the groups at any point afterthe operation. Both groups had a significant decrease in visualanalog scale scores after the femoral nerve block. No signifi-cant difference in postoperative narcotic medication use wasevident in the recovery room or at home. A post hoc analysisrevealed that the study power reached 87% with a significancelevel of 5%. Conclude that the postoperative femoral nerveblock was effective and intraarticular morphine provided noadditional benefit.

Comment

by Alan David Kaye, M.D., Ph.D., and Erin Ba-yer, M.D.

This prospective, randomized, double blinded study com-pared the effects of preoperative intraarticular injection ofmorphine or a placebo along with postoperative femoral“three-in-one” block on postoperative pain. 62 patients un-derwent arthroscopic ACL reconstruction under general anes-thesia. After induction of anesthesia, patients were injectedwith either morphine 5 mg or placebo along with local anes-thetics intraarticularly. Femoral nerve blocks were performedin the recovery room with a total of 3 mg/kg bupivacaine. TheVAS of pain was assessed immediately postoperatively and atsix time points afterward up to 24 hours. This study concludedthat there were no statistical differences between the twogroups comparing VAS. Also no significant difference was ob-served in postoperative narcotic use in the recovery room or athome. The study included antiemetics; however, the results didnot include if the morphine group had a larger incidence ofnausea or vomiting postoperatively. Finally, the authors sug-gest that there are no advantages to use of intraarticular mor-

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371

Anesthesia (4)

Laleh Aram, Elliot J. Krane, Lori J. Kozloski, Myron Yaster:

Tunneled epidural catheters for prolonged analgesia in pediat-ric patients. (Stanford University, Stanford, CA)

Anesthesiaand Analgesia

2001;92:1432–1438.

The charts of 25 patients with prolonged pain that was unre-sponsive to conventional opioid therapy and who received tho-racic, lumbar, or caudal tunneled epidural catheters between1995 and 1999 were reviewed for efficacy and catheter-relatedcomplications. Tunneled epidural catheters were effective inproviding extended analgesia in all subjects. In 14 patientswith chronic pain, cumulative 48-hour enteral and parenteralopioid requirements were reduced or eliminated after catheterinsertion. Catheters remained in place for a median of 11 daysuntil there was no further need for parenteral analgesia (n

�

15), death because of the underlying disease (n

�

6), acciden-tal removal (n

�

2), or possible infection (n

�

2). No seriouslocal or systemic complications occurred related to this tech-nique. Five patients were discharged from the hospital with thecatheter for home analgesic therapy. The use of a percutane-ously inserted, subcutaneously tunneled epidural catheter is safe,effective, and provides pain relief in situations in which con-ventional analgesic therapy either fails or is impractical. Thetechnique is one that may be of great value to children suffer-ing from pain.

Comment

by Alan David Kaye, M.D., Ph.D., Amr Hegazi,M.D.

This retrospective study assessed the safety, efficacy, com-plications, indications, and duration of use of subcutaneouslytunneled lumbar, thoracic and caudal epidural catheters in pe-diatric patients with prolonged pain.

The authors examined a total of 25 patients hospitalizedfor treatment of acute pain caused by trauma as well aschronic pain resulting from end-stage cancer or cystic fibrosis.The catheters were introduced under either local anesthesiawith sedation or general anesthesia after obtaining informedparental consent. Epidural catheters were inserted percutane-ously, then tunneled subcutaneously away from the insertionsite to bring the catheter exit site to the anterior abdominaland thoracic, posterior superior iliac crest to decrease the riskof potential infection and chance of catheter dislodgement.Tunneled catheters were effective in providing extended anal-gesia in all patients. None of the acutely ill patients requiredsupplemental enteral or parenteral opioids while pediatric pa-tients with chronic pain had dramatic decrease or eliminationof opioid needs.

Two of these patients had accidental removal of the cathe-ter. One patient had postoperative fever with possible presenceof infection and another patient developed cellulites at thecatheter exit site. Both the catheter and wound site were sterileon bacterial cultures. The clinical relevance of routine microbi-ological culturing of epidural catheters in acute pain manage-ment has been evaluated by Simpson

et al.

It was concludedthat a significant proportion of catheter tips can be positive.This suggests that colonization of the skin at the insertion siteand subsequent contamination of the tip upon removal of the

catheter is a concern and strict sterile aseptic techniquesshould be practiced by the anesthesiologist. This is an interest-ing article because at most institutions, pediatric pain and cer-tainly critically ill children are clearly undermanaged. Thesmall size of the study group, however, enables us to appropri-ately define the risk of infection for long-term catheter place-ment (up to 240 days in this article). Also accidental catheterdislodgement especially on patients discharged home with anepidural catheter remains a concern.

Anesthesia (5)

Stuart A. Grant, Karen C. Nielsen, Roy A. Greengrass, SusanM. Steele, Stephen M. Klein:

Continuous peripheral nerveblock for ambulatory surgery. (Duke University, Durham,NC)

Reg Anesth Pain Med

2001;26:209–214.

In this study data was prospectively gathered for 1 year from228 patients in an ambulatory surgery center. All continuousperipheral nerve blocks (CPNB) were performed using the Con-tiplex system to provide anesthesia and postoperative analge-sia. CPNB were performed using 5 upper and lower extremitytechniques. Postsurgery local anesthetic was infused and at 24hours, a rebolus of local anesthetic was performed. The CPNBcatheter was removed and patients were examined for a loss ofsensation. Patients were then discharged. The initial peripheralblock was successful in 94% of the patients. Failed nerve blockrequiring general anesthesia occurred in 6%. The catheter waspatent and functional in 90% of the patients at 24 hours, and8% of the patients required more than 10 mg of intravenousmorphine by 24 hours postsurgery. In the postanesthesia careunit, only 4 patients (1.7%) required treatment for nausea. At24 hours and 7 days postsurgery, no patient reported a dyses-thesia. Conclude that CPNB using the insulated Tuohy cathetersystem offered acceptable anesthesia and prolonged pain reliefpostsurgery. There were few side effects.

Comment

by Alan David Kaye, M.D., Ph.D., Erin Bayer, M.D.This study demonstrates the efficacy of the Contiplex sys-

tem (CPNB) in providing surgical anesthesia and postopera-tive analgesia through CPNB. Despite the efficacy of CPNB,which could provide longer duration of postoperative analge-sia than single injection block, it is not widely used due to lackof available equipment. Contiplex system utilizes a connectorfor a nerve stimulator attached to a 18-gauge Tuohy needle. Itallows for aspiration of blood, injection of local anesthesiaand passage of a peripheral nerve catheter. This study demon-strated in an ambulatory surgery center with 228 patients,CPNB was used for 27 different types of surgical procedureswhich involved 5 different block sites. Success rates were 94%for initial peripheral block while 6% required general anesthe-sia. Patients required less postoperative analgesia. The inci-dence of postoperative side effects such as nausea and vomit-ing were minimal. Not a single patient reported dissatisfiedwith a 7-day telephone follow-up. A disadvantage of this tech-nique is the use of an 18-gauge needle and potential for vascu-lar and/or nerve injuries, which did not occur in this study.Though previous studies have demonstrated the efficacy ofthe CPNB in inpatients, this is an important study focused on

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multidisciplinary abstracts

outpatients. A larger study group will be valuable in futurestudies.

Anesthesia (6)

Argyro Fassaoulaki, Constantine Sarantopoulos, AikateriniMelemeni:

Regional block and mexiletine: the effect on painafter cancer breast surgery. (St. Savas Hospital, Athens,Greece)

Reg Anesth Pain Med

2001;26:223–228.

This study investigated the effect of regional block, oral mexi-letine, and the combination of both, on acute and chronic painassociated with cancer breast surgery. One hundred patientsscheduled for cancer breast surgery received either regionalblock with 18 mL of 1% ropivacaine intraoperatively and oralmexiletine for the first 6 postoperative days or regional blockand placebo (R

�

PL), or normal saline instead of ropivacaineand mexiletine (PL

�

M), or normal saline and placebo (PL

�

PL). Postoperative analgesic requirements were recorded daily.Pain was assessed 0, 3, 6, 9, and 24 hours in the postanesthesiacare unit and on the 2

nd

to 6

th

day postoperatively, at rest, andafter movement using the visual analog scale. Three months af-ter surgery, the patients were interviewed for the presence andintensity of pain, abnormal sensations, and analgesic require-ments. Regional block reduced the number of intramuscularinjections required the first 24 hours with the R

�

PL group re-quiring less injections versus the PL

�

M group. Three monthsafter surgery, the 4 groups were similar with regard to inci-dence or intensity of pain or analgesic requirements. The R

�

PL group has a lower incidence (77%) of reduced or absentsensation. Conclude that regional block reduced the analgesicrequirements in the early postoperative period, while mexile-tine combined with regional block reduced the total analgesicrequirements during the next 5 postoperative days.

Comment

by Pedro F. Bejarano, M.D.This study illustrates that statistical significance may not

necessarily mean clinical significance. Some conclusions of thisDB randomized controlled trial goes along with current knowl-edge in acute pain management:

First, although somehow controversial from the standpointof the global postoperative outcome, there is great consensuson the concept that regional anesthesia may provide betterpain relief in the early postoperative period as compared withsystemic analgesia. Secondly, combined analgesia (regional

�

systemic) may further enhance this benefit, and in the lack ofevidence of a specific “pre-emptive” effect of a sodium-chan-nel blocker like mexiletine, we wisely assume that the lowerpain scores obtained in the first 5 postoperative days of thiscombination represents such a systemic combined analgesic ef-fect. Third, the statistical difference favoring superior analge-sia at three-hours postoperative period in the regional

�

pla-cebo over the regional

�

mexiletine groups can only be explainedin the basis of a difference in extension and/or nerve blockdepth due to technical difficulties or anatomical differenceswithin the groups.

Conversely to the previous conclusions, the suggested ae-thiological-correlation of the statistical difference favoring theregional

�

mexiletine group in the diminished frequency of

hypoesthesia remains doubtful, facing the known correlationof this symptom as a direct consequence of the surgical neuraltissue damage. To our knowledge, there is no theoretical basisfor making such an assumption, and even less from a study onwhich the power and alfa-error calculations of the sample weremade on the grounds of finding analgesic dosing differences.

Anesthesia (7)

Katsushi Doi, Yoji Saito, Tetsuro Nikai, Noriko Morimoto,Toshihiko Nakatani, Shinichi Sakura:

Lumbar sympathetic blockfor pain relief in two patients with interstitial cystitis. (Shi-mane Medical University, Izumo, Japan)

Reg Anesth Pain Med

2001;26:271–273.

This case report discussed the effective treatment of interstitialcystitis (IC) with regard to a 63-year-old woman and a 78-year-old woman. Medical therapy with nonsteroidal anti-inflammatory drugs, anticholinergics, and hydrodistention ofthe bladder failed to improve their symptoms. Subsequently, acontinuous lumbar epidural block using 1% mepivacaine wasused in these patients. A transient reduction of the symptomsin both patients was achieved. A lumbar sympathetic blockwith a neurolytic agent produced almost complete and long-lasting relief of their symptoms. Conclude that lumbar sympa-thetic block using a neurolytic agent produced long-lastingpain relief in 2 patients with IC.

Comment

by Pedro F. Bejarano, M.D.Chronic visceral pain association to the neurovegetative sys-

tem and to sympathetically-maintained mechanisms has beenwell documented nowadays. The multiple neural connectionsamong different abdominal nerve plexus has also been de-scribed, and this anastomoses may account for the observed an-algesic effects in this case obtained without specific blockade ofthe superior hypogastric plexus. Despite the reported good re-sults, the use of the lumbar approach may be controversial inthis cases, as the uncomfortable peripheral effects of a perma-nent lumbar sympathetic neurolytic block (i.e.: lower limb va-sodilation) favors a more anatomically restricted (visceral) arealike that obtained with a superior hypogastric approach.

We must remark that the existence of Sympathetically me-diated and/or maintained pain is not enough phenomenae tofit the diagnostic criteria of a RCPS, as suggested by the au-thors, but it is less so in the case of an evidently persistent, or-ganic source of visceral nociception like in the Intersticial Cys-titis disease.

Anesthesia (8)

Zeev Crystal, Yeshayahu Katz:

Postoperative epidural analge-sia and possible transient anterior spinal artery syndrome.(HaEmek Medical Center, Afula, Israel)

Reg Anesth Pain Med

2001;26:274–277.

An unusual complication of epidural analgesia used to facili-tate postoperative pain relief while mobilizing a patient is pre-sented in this case report. A 65-year-old woman with a history

Multidisciplinary Abstracts

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373

of chronic obstructive pulmonary disease, atherosclerotic car-diovascular disease, chronic renal failure, and degenerativevertebral anatomy underwent resection of the left ureter due toan obstructing tumor. The day following the surgery, mobili-zation to an armchair was started, followed by a decrease inblood pressure. Soon after, flaccid paralysis was sparing ofsensory functions, consistent with anterior spinal artery syn-drome, was diagnosed. This complication should be taken intoaccount, especially in patients at risk, when considering epidu-ral analgesia techniques in the postoperative period.

Comment

by Pedro F. Bejarano, M.D.Fortunately infrequent, the Anterior Spinal Artery Syn-

drome (ASAS) has been described in the early postoperativeperiod in association with surgery involving the retroperito-neum (specially on the left side), as well as unexpectedly withregional anesthesia procedures (Spinal, Epidural and CeliacPlexus Blocks) in the vicinity of the T6 to L2 “critical zone” ofmedulary arterial blood flow.

1,2

This case highlights the im-portance of a proper evaluation and prevention when feasible,of combining risk factors (besides type of surgery and anes-thetic technique) that may potentiate otherwise subclinical—but certainly prevalent—vascular, circulatory or spinal anat-omy aging derangements leading to ASAS.

As the authors state in the discussion of this case, it is re-markable the aethiological association with an apparentlyuncomplicated and retrospectively “preventable” hypotensiveepisode, whether it be a consequence of a relative hypo-volemia, a pharmacological (postanesthetic or not) impair-ment of baropressor responses, or to an excessive local anes-thetic sympathetic blockade.

Learning from unexpected negative outcomes in anesthesiamakes us more sensible to risk factors that are not speciallyhighlighted in daily practice. In this sense, a case with so multi-ple patient’s risk factors including the diagnosis of spinalstenosis, may had lead to other postop analgesia choices,namely systemic or even sole epidural opioid analgesia (thatmaybe was not considered here due to the COPD) as has beensuggested before.

3

Moreover, in the scope of an obstructivecoronary disease high-risk patient, a more aggressive treat-ment to the hypotensive episode including quick return to therecumbent or trendelemburg position limiting the isquemiacould have favored this neurological adverse outcome.

1. Hong DK, Lawrence HM: Anterior Spinal Artery Syn-drome following total Hip Artroplasty.

Anesth Intensive Care.

2001;29:62–66.2. Hachisuka K, Ogata H, Kohshi K: Postoperative Para-

plegia with spinal myoclonus possibly caused by epidural an-aesthesia: case report.

Paraplegia.

1991 Feb;29(2):131–136.3. Linz SM, Charbonnet C, Mikhail MS, et al.: Spinal ar-

tery syndrome masked by postoperative epidural analgesia.

Can J Anaesth.

1997;44(11):1178–1181.

Anesthesia (9)

Donna Kalauokalani, Karen J. Sherman, Daniel C. Cherkin:

Acupuncture for chronic low back pain: diagnosis and treat-

ment patterns among acupuncturists evaluating the same pa-tient. (Washington University School of Medicine, St. Louis,MO)

Southern Med J.

2001;94:486–492.

In this case study 7 office-based acupuncturists practicing Tra-ditional Chinese Medicine evaluated the same patient withchronic low back pain and provided data regarding principalassessment techniques, diagnoses, and therapeutic recommen-dations. A high diagnostic agreement existed among 5 of 7acupuncturists. However, recommended treatments includedvarying numbers and locations of acupuncture points. Recom-mendations varied between 5 and 14 points requiring 7 to 26needles, since many points were intended for bilateral applica-tion. Of 28 acupuncture points selected, only 4 (14%) wereprescribed by 2 or more acupuncturists. Most recommendedvarious forms of adjuvant heat. Conclude that 7 acupunctur-ists agreed considerably in the diagnoses for the same patientwith chronic low back pain, but treatment recommendationsvaried substantially. Clinicians and researchers must recognizetreatment recommendation variations and the challenges theypresent for study design interpretation.

Anesthesia (10)

Stuart A. Grant, Karen C. Nielsen, Roy A. Greengrass, SusanM. Steele, Stephen M. Klein:

Computed tomography-guidedneurolytic celiac plexus block with alcohol complicated by su-perior mesenteric venous thrombosis. (University of Washing-ton, Seattle, WA)

Pain.

2001;92:307–310.

This case report discussed a 62-year-old woman who sufferedfrom intractable, tumor-associated pain. Neurolytic celiacplexus block (CPB) under radiological guidance is often per-formed to manage pain associated with pancreatic cancer. Se-rious complications related to the block are rare. Computedtomography (CT)-guided neurolytic CPB is advocated to im-prove the efficacy of the block and to reduce the incidence ofassociated complications.

Anesthesia (11)

J. M. Davies, A. Murphy, M. Smith, G. O’Sullivan:

Subduralhematoma after dural puncture headache treated by epiduralblood patch. (St. Thomas Hospital, London, United Kingdom)

British J Anesth.

2001;86:720–723.

This case study discussed an accidental dural puncture in a 39-year-old patient during the siting of an epidural catheter forpain relief in labor. Twenty hours after the puncture, themother developed a typical postdural headache, which in-creased in severity over the subsequent 24-hour period. Anepidural blood patch was performed at 48 hours, and this ini-tially relieved the headache. After discharge from the hospital,and 14 days after the dural puncture, the headache recurred,together with expressive dysphasia, poor coordination, andsensory loss in the right arm. A magnetic resonance imagingscan demonstrated a left-sided subdural hematoma, whichdrained successfully with complete recovery.

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multidisciplinary abstracts

Anesthesia (12)

C. Connolly, D. M. Coventry, J. A. Wildsmith:

Double-blindcomparison of ropivacaine 7.5 mg mL

�

1

for sciatic nerveblock. (Ninewells Hospital and Medical School, Dundee,United Kingdom)

British J Anesh.

2001;26:209–214.

Two groups of 12 patients had a sciatic nerve block performedwith 20 mL of either ropivacaine 7.5 mg mL

�

1

or bupivacaine5 mg mL

�

1

. There was no statistically significant difference inthe mean time to onset of complete anesthesia of the foot or tothe first request for postoperative analgesia. The quality of theblock was the same in each group. Although there is no statis-tically significant difference in the mean time to peak plasmaconcentrations the mean peak concentration of ropivacainewas significantly higher than that of bupivacaine. There wereno signs of systemic local anesthetic toxicity in any patient ineither group.

Anesthesia (13)

Laurie Allan, Helen Hays, Niels-Henrik Jensen, Bernard LePolain de Waroux, Michiel Bolt, Royden Donald, Eija Kalso:

Randomized crossover trial of transdermal fentanyl and sus-tained release oral morphine for treating chronic noncancerpain. (University of Alberta, Alberta, Canada)

British J Anesh.

2001;322:1154–1158.

This study involved 256 patients with chronic noncancer painwho had been treated with opioids. Of 212 patients, 138(65%) preferred transdermal fentanyl, whereas 59 (28%) pre-ferred sustained release oral morphine and 15 (7%) expressedno preference. Better pain relief was the main preference forfentanyl given by 35% of the patients. These results were re-flected in both the patients, and the investigators’ opinions onthe global efficacy of transdermal fentanyl. The incidence ofadverse events was similar in both treatment groups; however,more patients experienced constipation with morphine thanwith fentanyl. Overall, 41% of the patients experienced mildor moderate cutaneous problems associated with wearing thetransdermal fentanyl patch, and more patients withdrew be-cause of adverse events during treatment with fentanyl thanwith morphine. Conclude that transdermal fentanyl was pre-ferred to sustained release oral morphine by patients withchronic noncancer pain previously treated with opioids withthe main reason being better pain relief.

Basic Science (14)

Allen H. Hord, Donald D. Denson, Barry Stowe, Robert M.Haygood:

�

-1 and

�

-2 adrenergic antagonists relieve thermalhyperalgesia in experimental mononeuropathy from chronicconstriction injury. (Emory University School of Medicine, At-lanta, GA)

Anesth Analg.

2001;92:1558–1562.

Phentolamine, a nonspecific

�

1- and

�

2-adrenergic antago-nist, relieves pain in patients with reflex sympathetic dystro-phy. This study sought to determine whether phentolamine,

prazosin (

�

1 antagonist), or SKF86466 (

�

2 antagonist) relievethermal hyperalgesia in rats with neuropathic pain. Four daysafter producing a chronic constriction injury (CCI), thermalhyperalgesia was tested by measuring paw withdrawal latency(PWL). After injection of phentolamine, prazosin, or SKF86466each at doses of 1, 2, or 5 mg/kg, PWL tests were measured at5 minutes and repeated at 15-minute intervals for 1 hour.Phentolamine, prazosin, and SKF86466 1, 2, and 5 mg/kg pro-vided statistically significant analgesia in rats with CCI for atleast 65 minutes. PWL did not return to baseline levels after 1or 2 mg/kg of prazosin or SKF86466 but did so after 35 min-utes after phentolamine 2 mg/kg. After 5 mg/kg, for phentola-mine, at 35 and 65 minutes for prazosin, and at 50 minutes forSKF86466, and at 50 minutes for SKF86466. Conclude thatboth

�

1 and

�

2 peripheral receptors of the sympathetic ner-vous system are involved in the thermal hyperalgesia caused byCCI and that thermal hyperalgesia can be reversed by both

�

1and

�

2 antagonists in a dose-dependent manner.

Basic Science (15)

J. Azami, D. L. Green, M. H. T. Roberts, R. Monhemius:

Thebehavioral importance of dynamically activated descending in-hibition from the

nucleus reticularis gigantocellularis pars al-pha

. (University Hospital of Wales, Cardiff, United Kingdom)

Pain

2001;92:53–62.

This study demonstrates the effects of

nucleus reticularis gi-gantocellularis pars alpha

(GiA) on the behavioral responseduring application of standardized noxious stimuli. As thissystem is activated in response to noxious stimulation, it ispossible that chronic pain states may also activate GiA. There-fore, this study investigated this possibility in animals follow-ing partial sciatic nerve ligation (an animal model of chronicpain). Male Wistar rats (280–310 g) were anesthetized withhalothane (0.5% to 2% in O

2

). Guide cannulae for microin-jections were stereotaxically placed above GiA. In one groupof animals the sciatic nerve was partially litigated. Animalswere allowed to recover for 4–6 days. The responses of eachanimal during the formalin test and the tail flick test wererecorded on different days. Microinjections (0.5

�

l) of either

�

-aminobutyric acid (GABA, 200 mM), D-L homocysteic acid(DLH, 25 mM), or 0.9% saline (as control) into GiA were pre-formed during these tests in a randomized, blind manner. Inanimals without sciatic nerve ligation, microinjection ofGABA to GiA did not significantly affect the animal’s responseduring the tail flick test. However, microinjection of DLH sig-nificantly increased the latency of tail flick from 6.2

�

0.8 to8.4

�

0.5 seconds for up to 15 minutes. Microinjection ofGABA to GiA increased the behavioral response to formalinbetween 10 and 20 minutes postinjection, while microinjec-tion of DLH reduced this response at all time points except 10minutes postinjection (n

�

8, p

0.05, Mann-Whitney

U

-test).In animals with sciatic nerve ligation, microinjections (0.5

�

l)of either GABA (200 mM), or saline (as control) into GiA con-tralateral to the partial sciatic ligation were performed duringthese tests in a randomized, blind manner. Partial sciatic liga-tion significantly reduced the behavioral response to contralat-

Multidisciplinary Abstracts

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375

erally applied formalin from 15 minutes postinjection onwards,compared to controls without sciatic nerve ligation. Microin-jection of GABA GiA significantly increased the behavioral re-sponse to formalin from 20 to 50 minutes postinjection. Theinactivation of GiA only causes behavioral effects in nocicep-tive tests of a long enough duration to activate the system (ie,the formalin test but not the tail flick test). Chemical activationof the system affects both tests. Conclude that these datastrongly support the concept of an important analgesic systemthat is activated in response to noxious stimulation, and subse-quently acts to reduce behavioral responses to noxious stimuli.

Comment

by Leland Lou, M.D.This is a rat study that looked at the presence of inhibitory

spinal multireceptive cells modifying and decreasing the be-havioural response to noxious stimuli. While no direction wasgiven as to the source of noxious stimuli inhibition in chronicpain, great effort was made to report a possible differential re-sponse of the C-fiber pain system versus the large sensory fi-bers. After review it seems that the authors believed that thenucleus reticularis gigantocellularis pars alpha maybe a centralprocessor of the inhibitory response. It is still too early to as-sess the clinical impact of this study.

Basic Science (16)

Yu-Chuan Tsai, Shen-Jeu Won:

Effects of tramadol on T lym-phocyte proliferation and natural killer cell activity in rats withsciatic constriction injury. (National Cheng Kung University,College of Medicine, Tainan, Taiwan)

Pain.

2001;92:63–69.

This study investigated the effects of acute and chronic trama-dol treatment on T lymphocyte function and natural killer(NK) cell activity in rats receiving chronic constriction injury(CCI) of the sciatic nerve. T lymphocyte function was evalu-ated based on concanavalin-A (ConA)-induced and phytohem-agglutinin (PHA)-induced splenocyte proliferation. NK cellactivity was measured by lactic acid dehydrogenase release as-say. The effects of tramadol on thermal hyperalgesia were alsoassessed by measuring paw withdrawal latency (PWL) in therats. PWL was dose-dependently reversed by tramadol afteracute treatment (single subcutaneous injection) with 10, 20,and 30 mg/kg, respectively. There was no significant changeamong acute treatments groups in NK cell activity, whereassplenocyte proliferation induced by ConA and PHA was sig-nificantly suppressed starting from a dose of 20 mg/kg. The re-versal of the thermal hyperalgesia persisted throughout a pe-riod of chronic tramadol treatment of 40 and 80 mg/kg perday, respectively, with continuous subcutaneous infusion for 7days at a uniform rate via osmotic minipumps. No modulationof NK cell activity was found in either dose group. However,the activity of splenocyte proliferation was decreased in the 80mg/kg per day group when compared with the saline and 40mg/kg per day groups. Suggest that tramadol treatment has animmunological profile different from pure

�

-opioid agonistslike morphine, which is known to suppress both NK cell activ-ity and T lymphocyte proliferation at a subanalgesic dose inCCI rats. Conclude that tramadol treatment may be a better

choice than morphine for treatment of chronic neuropathicpain, particularly in patients with compromised immunity.

Basic Science (17)

S. Bingham, P. T. Davey, A. J. Babbds, E. A. Irving, M. J. Sam-mons, M. Wyles, P. Jeffrey, L. Cutler, I. Riba, A. Johns, R. A.Porter, N. Upton, A. J. Hunter, A. A. Parsons:

Orexin-A, anhypothalamic peptide with analgesic properties. (SmithKlineBeecham Pharmaceuticals, Harlow, Essex, United Kingdom)

Pain.

2001;92:81–90.

The hypothalamic peptide orexin-A and the orexin-1 receptorare localized in areas of the brain and spinal cord associatedwith nociceptive processing. In the present study, localizationwas conformed in the spinal cord and demonstrated in thedorsal root ganglion for both orexin-A and the orexin-1 recep-tor. The efficacy of orexin-A was similar to that of morphinein the 50°C hotplate test and the carrageenan-induced thermalhyperalgesia test. However, involvement of the opiate systemin these effects was ruled out as they were blocked by the or-exin-1 receptor antagonist SB-334867, but not naloxone. Or-exin-1 receptor antagonists had no effect in acute nociceptivetests, but under particular inflammatory conditions were pro-hyperalgesic, suggesting a tonic inhibitory orexin drive in thesecircumstances. Conclude that the orexinergic system has a po-tential role in the modulation of nociceptive transmission.

Basic Science (18)

Alyson Fox, Adam Kesingland, Clive Gentry, Kara McNair,Sadhana Patel, Laszlo Urban, Iain James:

The role of centraland peripheral Cannabinoid

1

receptors in the antihyperalgesicactivity of cannabinoids in a model of neuropathic pain. (No-vartic Institute for Medical Sciences, London, United King-dom)

Pain.

2001;92:91–100.

This study examined the effects of cannabinoid agonists on hy-peralgesia in a model of neuropathic pain in the rat and inves-tigated the possible sites of action. The antihyperalgesic activ-ity of the cannabinoids was compared with their ability toelicit behavioral effects characteristic of central cannabinoidactivity. WIN55, 212-2 (0.3–10 mg/kg

�

1

), CP-55, 940 (0.03–1mg/kg

�

1

), and HU-210 (0.001–0.03 mg/kg

�

1

) were all activein a “tetrad” of tests consisting of tail-flick, catalepsy, rotarod,and hypothermia following subcutaneous administration, witha rank order of potency in each of HU-210

CP-55, 940

WIN55, 212-2. The effects of WIN55, 212-2 in each assay wereblocked by the Cannabinoid

1

(CB

1

) antagonist SR141716A. Inthe partial sciatic ligation model if neuropathic pain WIN55,212-2, CP-55, 940, and HU-210 produced complete reversalof mechanical hyperalgesia within 3 hours of subcutaneous ad-ministration with D

50

values of 0.52, 0.08, and 0.005 mg/kg

�

1

,respectively. In this model WIN55, 212-2 was also effectiveagainst thermal hyperalgesia and mechanical allodynia. WIN55,212-2 produced pronounced reversal of mechanical hyperal-gesia following intrathecal administration that was blockedby the CB

1

antagonist SR141716A. Following intraplantar ad-

376

•

multidisciplinary abstracts

ministration into the ipsilateral hindpaw, WIN55, 212-2 pro-duced up to 70% reversal of mechanical hyperalgesia, althoughactivity was also observed at high doses following injectioninto contralateral paw. The antihyperalgesic effect of WIN55,212-2 injected into the ipsilateral paw was blocked by subcu-taneously administered SR141716A, but was not affected byintrathecally administered SR141716A. Conclude that can-nabinoids are highly potent and efficacious antihyperalgesicagents in a model of neuropathic pain. This activity is likely tobe mediated via action in both the CNS and in the periphery.

Comment

by Leland Lou, M.D.Rat study that looked at the potential of cannabinoids in

the management of neuropathic pain. The data seem to indi-cate the presence of peripheral cannabinoid receptors forsuppression of neuropathic pain. Historically, a central mech-anism of action for cannabinoid’s analgesic and antihyperalge-sic properties is thought to be responsible. Unfortunately, thisreport only confirms previous studies finding a peripheralmechanism of action.

Basic Science (19)

Volker Limmroth, Zaza Katsarava, Bernd Liedert, HansGuehring, Kerstin Schmitz, Hans-Christoph Diener, Martin C.Michel:

An in vivo rat model to study calcitonin gene relatedpeptide release following activation of the trigeminal vascularsystem. (Department of Neurology, University of Essen, Essen,Germany) Pain. 2001;92:101–106.

This report described a new rat model, which allowed thestudy of calcitonin gene related peptide (CGRP) release fromthe meninges into venous blood following activation of thetrigeminal vascular system. The effects of classical and new an-timigraine drugs as acetylsalicylic acid (ASA), sumatriptan andthe new high efficacy 5-HT1B/1D agonist donitriptan (4-[4-[2-(2-aminoethyl)-1H-indol-5-yloxyl]acetyl]piperazinyl-1-yl]benzonitrile) were evaluated in comparison with the estab-lished model of neurogenic inflammation in the meninges.Sumatriptan and donitriptan inhibited CGRP release as well asneurogenic inflammation. ASA, however, attenuated neuro-genic inflammation, but not CGRP release, confirming the con-cept of prejunctional inhibition of CGRP release by 5-HT1B/1Dreceptors. This new model allows the further study of prejunc-tional pharmacology and mechanisms of neuropeptide releasein the trigeminal vascular system, which might be crucial forthe further development of potent, more effective anti-migrainedrugs.

Comment by Leland LouBasic migraine headache research report with the goal of

establishing trigeminal stimulation in rats as an equivalentsubstitute for the cat model and superior sagittal sinus stimula-tion is discussed. The 5-HT receptor agonists appeared to bemore efficacious than inflammation suppression with NSAIDsalone. Within the 5-HT receptor agonists group, donitriptanhad a statistical benefit greater than sumitriptan. In summarythe rat model results are similar to the cat migraine model with

an increase in calcitonin gene related peptide levels and neuro-genic inflammation.

Basic Science (20)

Elizabeth A. Matthews, Anthony H. Dickenson: Effects of spi-nally delivered N- and P-type voltage-dependent calcium chan-nel antagonists on dorsal horn neuronal responses in a ratmodel for neuropathy. (Department of Pharmacology, Univer-sity College London, London, United Kingdom) Pain. 2001;92:233–246.

Neuropathic pain, due to peripheral nerve damage, can in-clude allodynia (perception of innocuous stimuli as being pain-ful), hyperalgesia (increased sensitivity to noxious stimuli) andspontaneous pain, often accompanied by sensory deficits. Plas-ticity in transmission and modulatory systems are implicatedin the underlying mechanisms. The Kin and Chung rodentmodel of neuropathy employed involved unilateral tight liga-tion of 2 (L5 and L6) of the 3 (L4, L5, and L6) spinal nerves ofthe sciatic nerve and reproducibly induced mechanical andcold allodynia in the ipsilateral hindpaw over the 14 day post-operative period. In vivo electrophysiological techniques havethen been used to record the response of dorsal horn neuronesto innocuous and noxious electrical and natural (mechanicaland thermal) stimuli after spinal nerve ligation (SNL). Activa-tion of voltage-dependent calcium channels (VDCCs) is criti-cal for neurotransmitter release and neuronal excitability, andantagonists can be antinociceptive. Here, for the first time, theeffect of N-type and P-type VDCC antagonists (�-conotoxin-GVIA and �-agatoxin-IVA, respectively) on the evoked dorsalhorn neuronal responses after neuropathy have been investi-gated. Conclude both presynaptic and postsynaptic VDCCsappear to be important.

Basic Science (21)

Keishi Hashimoto, Karl F. Hampl, Yuji Nakamura, AndrewW. Bollen, John Feiner, Kenneth Drasner: Epinephrine increasesthe neurotoxic potential of intrathecally administeredlidocaine in the rat. (Department of Anesthesia and Preopera-tive Care, University of California, San Francisco, CA) Anes-thesiology. 2001;94:876–881.

This study investigated whether adding epinephrine increasesfunctional impairment or histologic damage induced by spinaladministration of lidocaine in the rat. Eighty rats were dividedinto 4 groups to receive an intrathecal injection of normal sa-line containing 5% lidocaine, 5% lidocaine with 0.2 mg/mL ofepinephrine, 0.2 mg/mL of epinephrine, or normal saline alone.Animals were assessed for persistent sensory impairment usingthe tail-flick test administered 4 to 7 days after infusion. Ani-mals were then killed, and the spinal cord and nerve rootswere prepared for neuropathologic evaluation. Rats given 5%lidocaine developed persistent sensory impairment and histo-logic damage, and the addition of epinephrine resulted in afurther significant increase in injury. Sensory function in ani-mals given epinephrine without anesthetic was similar to base-

Multidisciplinary Abstracts • 377

line and did not differ from saline. Histologic changes in ani-mals treated with epinephrine alone did not differ significantlyfrom saline controls. Conclude the neurotoxicity of intrathe-cally administered lidocaine is increased by the addition of epi-nephrine. When making clinical recommendations for maxi-mum safe intrathecal dose of this anesthetic, one may need toconsider whether the solution contains epinephrine.

Comment by Octavio Calvillo, M.D., Ph.D.The authors studied the neurotoxicity of epinephrine added

to lidocaine injected intrathecally in rats. The animals were al-located to four groups of 20 rats each, receiving: normal salinealone, normal saline and 5% lidocaine, 5% lidocaine with epi-nephrine [0.2 mg/ml] in saline or epinephrine 0.2 mgml in sa-line. The animals were assessed for sensory deficits 4 and 7days after infusion and then sacrificed. The spinal cords andnerve roots were prepared for neuropathological evaluation.Sections obtained from animals treated with lidocaine, lido-caine with epinephrine. Rats given 5% lidocaine developedpersistent sensory impairment and histological evidence ofdamage, the addition of epinephrine, resulted in further dam-age. Histological changes in animals treated with epinephrinealone did not differ significantly from saline controls. The au-thors concluded that the neurotoxicity of intrathecally-admin-istered lidocaine is increased by the addition of epinephrine.They raised the possibility that the neurotoxicity of commer-cially available epinephrine may be due to the bisulfite con-tained therein, this chemical has been associated with neuro-toxicity.

Basic Science (22)

Serge Perrot, Gisèle Guilbaud, Valérie Kayser: Differential be-havioral effects of peripheral and systemic morphine and na-loxone in a rat model of repeated acute inflammation. (Unitéde Physiopharmacologie du Système Nerveux, Paris, France)Anesthesiology. 2001;94:870–875.

This study compared the behavioral effects of intraplantar andintravenous morphine and naloxone in a rat model of repeatedacute carrageenan-induced inflammation in which enhancedresponse to noxious stimuli result from sensitization in periph-eral tissues or central sensitization. After the first carrageenaninjection, intraplantar and intravenous morphine producedsignificant increase of vocalization thresholds to paw pressurein inflamed, but not in noninflamed paws. After the secondcarrageenan injection, the antinociceptive effects of intraplan-tar morphine were significantly reduced compared with thoseobtained after the first carrageenan injection, whereas effectsof intravenous morphine were significantly enhanced andpresent in both hind paws. Intravenous naloxone demon-strated similar pronociceptive patterns after the first and sec-ond carrageenan injection. Intraplantar naloxone methiodideproduced pronociceptive effects in inflamed hind paw thatwere significantly enhanced after the second carrageenan in-jection. Conclude that when the inflammation is enhanced byrecurrent stimulations, the antinociceptive effects of systemicmorphine are enhanced. This increase is more likely related to

central than peripheral sites of action, beyond endogenousopioid system activation.

Comment by Octavio Calvillo, M.D., Ph.D.There is evidence that opioid antinociception is enhanced in

the presence of inflammation. In fact, there is evidence that opi-oids produce analgesia through peripheral opioid receptorswithin inflamed tissue. Primary afferent neurons are known tocontain opioid receptors. It remains unclear whether the anti-nociceptive effects of opioids are related predominantly to cen-tral, peripheral sites of action or both. The authors comparedthe effects of intraplantar and intravenous morphine and na-loxone in a rat model of carrageenan-induced inflammation. Inthis model, hyperalgesia is due probably to both peripheral andcentral sensitization. The antinociceptive effects of intraplantarmorphine, intravenous morphine, intraplantar naloxone, andintravenous naloxone were assessed on the vocalization thresh-olds to noxious pressure 3 hours after carrageenan plantar injec-tions. Intraplantar and intravenous morphine increased the vo-calization thresholds after carrageenan injection in inflamed butnot on noninflamed paws. The antinociceptive effects of intra-plantar morphine were reduced compared to the first responsewhereas the effects of intravenous morphine were significantlyenhanced and present on both inflamed and noninflamed paws.Intravenous naloxone demonstrated similar pronociceptivepatterns after the first and second carrageenan injection. Intra-plantar naloxone produced pronociceptive effects in inflamedhind paws that were significantly enhanced after the second car-rageenan injection. The authors concluded that when inflamma-tion is enhanced by recurrent stimulation the antinociceptive ef-fects of systemic morphine are enhanced. This is more probablyrelated to central than to peripheral sites of action.

Basic Science (23)

Seiji Ohtori, Kazuhisa Takahashi, Tanemichi Chiba, Masat-sune Yamagata, Hiroaki Sameda, Hideshige Moriya: Pheno-typic inflammation switch in rats shown by calcitonin gene-related peptide immunoreactive dorsal root ganglion neuronsinnervating the lumbar facet joints. (School of Medicine,Chiba University, Chiba, Japan) Spine. 2001;26:1009–1013.

This study’s objective was to determine by inflammatory stim-ulation the changes in calcitonin gene-related peptide-immu-noreactive dorsal root ganglion neurons innervating the L5-L6facet. Retrograde transport of fluorogold was used in 20 rats:10 in the control group and 10 in the inflammatory group. Us-ing the dorsal approach, fluorogold crystals were injected intothe left L5-L6 facet joint. Then 5 days after application, com-plete Freund’s adjuvant (50 injected �g Mycobacterium bu-tyricum in oil saline emulsion) was injected into the sameL5-L6 facet joint (inflammatory group). Of the total fluo-rogold-labeled dorsal root ganglion neurons from T13-L6, thenumber and cross-sectional area of the cell profiles of fluo-rogold-labeled, calcitonin gene-related peptide-immunoreac-tive neurons in the bilateral dorsal root ganglia of both groupswere evaluated. Fluorogold-labeled neurons were distributedthroughout the ipsilateral dorsal root ganglia from L1-L5 in

378 • multidisciplinary abstracts

both groups. Of the fluorogold-labeled neurons, the ratios ofthe calcitonin gene-related peptide-immunoreactive L1, L2,L3, L4, and L5 dorsal root ganglion neurons, respectively,were 17%, 24%, 44%, 56%, and 50% in the control groupand 50%, 39%, 51%, 61%, and 56% in the inflammatorygroup. The ratios of the calcitonin gene-related peptide-immu-noreactive L1 and L2 dorsal root ganglion neurons labeled byfluorogold were significantly higher in the inflammatorygroup than in the control group (P 0.05). The mean cross-sectional area of fluorogold-labeled, calcitonin gene-relatedpeptide-immunoreactive cells from the L1-L5 dorsal root gan-glia increased from 621 � 64 �m2 to 893 � 63 �m2 in the in-flammatory group (P 0.01).

Comment by Octavio Calvillo, M.D., Ph.D.This is a bench research study that demonstrated sympa-

thetic activation of dorsal root ganglia distal to the pain re-sponse. The authors sought to establish the degree of innerva-tion of the L5-6 facet joint of the rat from sympathetic fibers ofL1 and 2 and to adjacent L3-5 segmental fibers. From histo-logical analysis, they found that inflammation increased theproduction of CGRP-Ir in the dorsal root ganglion of L1 andL2. Additionally, the nerve fibers were noted to increase in sizewith the inflammation. These findings lend support for upperlumbar dorsal root blockade for non-segmental levels of in-flammation.

Basic Science (24)

Hiroaki Sameda, Yuzuru Takahashi, Kazuhisa Takahashi,Tanemichi Chiba, Seiji Ohtori, Hideshige Moriya: Primarysensory neurons with dichotomizing axons projecting to thefacet joint and sciatic nerve in rats. (School of Medicine, ChibaUniversity, Chiba, Japan) Spine. 2001;26:1105–1109.

The object of this study was to clarify the existence of dorsalroot ganglion (DRG) neurons with dichotomizing axons pro-jecting to the lumbar facet joint and to the sciatic nerve in rats.Two kinds of neurotracers (Dil and FG) were used in thestudy. Dil crystals were placed in the left F5-F6 facet joint, andFG was applied to the ipsilateral sciatic nerve or along themidline of the F% dermatome. Bilateral DRGs T13-S1 wereobserved by fluorescence microscope. DRG neurons double la-beled with Dil and FG were recognized only in the ipsilateralDRGs from L3-L6 levels. Approximately 3% of DRG neuronsinnervating the L5-L6 facet joint had other axons to the sciaticnerve. By contrast, no double-labeled neurons were observedafter FG was applied to the L5 dermatome. Conclude that inrats approximately 3% of DRG neurons innervating the lum-bar facet joints have dichotomized axons projecting to the sci-atic nerve.

Clinical Science (25)

David Casarett, Jason Karlawish, Pamela Sankar, Karen B.Hirschman, David A. Asch: Obtaining informed consent forclinical pain research: patients’ concerns and informational

needs. (University of Pennsylvania Center for Bioethics, Phila-delphia, PA) Pain. 2001;92:71–79.

Investigators who conduct pain research are required to obtainvoluntary informed consent from patients. However, little isknown about what information patients expect when they de-cide whether to enroll in such studies. It is important that theinvestigators understand the need for information so that theycan effectively and clearly describe the research risks and po-tential benefits that matter to the potential subjects. This studywas designed to define information needs that patients havewhen they decide whether to participate in clinical pain re-search and identified clinical and demographic variables asso-ciate with specific needs.

Neurology (26)

Kenneth Schmader: Herpes zoster in older adults. (Duke Uni-versity Medical Center, Durham, NC) Clinical Infectious Dis-eases. 2001;32:1481–1486.

Herpes zoster (HZ) strikes millions of older adults annuallyworldwide and disables a substantial number of them via post-herpetic neuralgia (PHN). Key aged-related clinical, epidemio-logical, and treatment features of zoster and PHN are re-viewed in this article. HZ is caused by renewed replication andspread of the varicella-zoster virus (VZV) in sensory gangliaand afferent peripheral nerves in the setting of age-related, dis-ease-related, and drug-related decline in cellular immunity toVZV. VZV-induced neuronal destruction and inflammationcauses the principal problems of pain, interference with activi-ties in daily living, and reduced quality of life in elderly pa-tients. Recently, attempts to reduce or eliminate HZ pain havebeen bolstered by the findings of clinical trials that antiviralagents and corticosteroids are effective treatment for HZ andthat tricyclic antidepressants, topical lidocaine, gabapentin,and opiates are effective treatment for PHN. Although theseadvances have helped, PHN remains a difficult condition toprevent and treat in many elderly patients.

Comment by Miles Day, M.D.This article reviews the epidemiology clinical features diag-

nosis and treatment of acute herpes zoster. It also describes thetreatment of postherpetic neuralgia. While this is a good re-view for the primary care physician, the discussion for thetreatment for both acute herpes zoster and postherpetic neu-ralgia do not mention invasive therapy. It is well documentedin pain literature that sympathetic blocks with local anestheticand steroid as well as subcutaneous infiltration of active zosterlesions not only facilitate the healing of acute herpes zoster butalso prevents or helps decrease the incidence of postherpeticneuralgia. All patients who present to the primary care physi-cian with acute herpes zoster should have an immediate refer-ral to a pain management physician for invasive therapy.

The treatment of postherpetic neuralgia is a challenging ex-perience both for the patient and the physician. While thetreatments that have been discussed in this article are impor-tant, other treatments are also available. Regional nerve

Multidisciplinary Abstracts • 379

blocks including intercostal nerve blocks, root sleeve injec-tions, and sympathetic blocks have been used in the past totreat postherpetic neuralgia. If these blocks are helpful, onecan proceed with doing crynourlysis of the affected nerves oralso radio-frequency lesioning. Spinal cord stimulation hasalso been used for those patients who are refractory to nonin-vasive and invasive therapy. While intrathecal methylpred-nisolone was shown to be effective in the study quoted in thisarticle one must be cautious not to do multiple intrathecal ste-roid injections in these patients. Multilple intrathecal steroidinjections can lead to archnoiditis secondary to the accumula-tion of the steroid on the nerve roots and in turn causing wors-ening pain.

Neurology (27)

Michael Bennett: The LANSS Pain Scale: the Leeds assessmentof neuropathic symptoms and signs. (St. Gemma’s Hospice,Leeds, United Kingdom) Pain. 2001;92:147–157.

This study described the development and validation of anovel tool for identifying patients in whom neuropathic mech-anisms dominate their pain experience. The Leeds assessmentof neuropathic symptoms and signs (LANSS) Pain Scale isbased on analysis of sensory description and bedside examina-tion of sensory dysfunction, and provides immediate informa-tion in clinical settings. It was developed in 2 populations ofchronic pain patients. In the first, the use of sensory descrip-tors and questions were compared in patients with nociceptiveand neuropathic pain, combined with an assessment of sen-sory function. This data was used to derive a 7-item pain scale,consisting of grouped sensory description and sensory exami-nation with a simple scoring system. The LANSS Pain Scalewas validated in a second group of patients by assessing dis-criminant ability, internal consistency, and agreement by inde-pendent raters. Clinical and research applications of the LANSSPain Scale are discussed.

Neurology (28)

Anne Louise Oaklander: The density of remaining nerve end-ings in human skin with and without postherpetic neuralgia af-ter shingles. (Massachusetts General Hospital, Harvard Medi-cal School, Boston, MA) Pain. 2001;92:139–145.

Postherpetic neuralgia (PHN), which occurs in some patientsafter shingles, was used to investigate the neural determinantsof chronic pain. Skin biopsies were obtained from 38 adultswith or without PHN at least 3 months after healing of shin-gles on the torso. Vertical sections were immunolabeled againstPGP9.5, a pan-axonal marker, to measure the density of theremaining nerve endings in skin previously affected by shin-gles. Of 19 subjects without PHN, 17 had more than 670 neu-rites/mm2 skin surface area, and 18 of 19 subjects with PHNhad 640 or fewer neurites/mm2. PHN may be a “phantom-skin” pain associated with loss of nociceptors. The study im-plies that the absence of pain after shingles may require thepreservation of a minimum density of primary nociceptive

neurons, and that the density of epidermal innervation mayprovide an objective correlate for the presence or absence ofPHN pain.

Comment by Miles Day, M.D.This is a good article addressing one of the most difficult

chronic pain syndromes to treat. As you know postherpeticneuralgia can be devastating to the patients secondary to theongoing and sometimes incapacitating pain. This study doesnot attempt to explain the cause of postherpetic neuralgia. In-stead it establishes objective criteria that implies the absence ofpain after shingles may require preservation of a minimumdensity of primary nociceptor neurons and that this densitymay provide an objective correlate for the presence or absenceof postherpetic neuralgia pain. If the implication made by thestudy is true, it raises a question as to whether or not skin bi-opsy should be preformed on all patients who have just experi-enced a case of herpes zoster to determine whether or not theyare at risk for developing postherpetic neuralgia. Anotherquestion that may arise is whether or not we should empiri-cally treat certain patients for potential postherpetic neuralgiaif there neurite density falls below a certain established level.While the information from this study should not be used as asole factor in determining whether or not a patient with a pre-vious herpes zoster infection will develop postherpetic neural-gia it does add objective data to our armamentarium that canbe used to try to prevent or treat the devastating pain causedby postherpetic neuralgia.

Neurology (29)

M. Empl, S. Renaud, B. Erne, P. Fuhr, A. Straube, N.Schaeren-Wiemers, A. J. Steck: TNF-alpha expression in pain-ful and nonpainful neuropathies. (University Hospital, Basel,Switzerland) Neurology. 2001;56:1371–1377.

The objective of this study was to determine whether the cyto-kine tumor necrosis factor � (TNF-�) acts as a pain mediatorin neuropathic pain in humans. Patients with painful neurop-athies showed a stronger TNF-� immunoreactivity in myeli-nating Schwann cells relative to the epineurial backgroundstaining compared with patients with nonpainful neuropathy.Although there was no difference in sTNF-RI levels betweenpainful and nonpainful neuropathies, patients with a mechani-cal allodynia had elevated serums sTNF-RI as compared to pa-tients without allodynia. Conclude that TNF-� expression ofhuman Schwann cells may be up-regulated in painful neuropa-thies. The elevation of sTNF-RI in patients with centrally me-diated mechanical allodynia suggests that systemic sTNF-RIlevels may influence central pain processing mechanisms.

Neurology (30)

Leslie Foster, Larry Clapp, Marleigh Erickson, Bahman Jab-bari: Botulinum toxin A and chronic back pain: a randomized,double-blinded study. (Walter Reed Army Medical Center,Washington, DC) Neurology. 2001;56:1290–1293.

380 • multidisciplinary abstracts

This study investigated the efficacy of botulinum toxin A inchronic low back pain and associated disabilities. Thirty-oneconsecutive patients with chronic low back pain who met theinclusion criteria were studied. Each patient’s baseline level ofpain and degree of disability was documented using the visualanalogue scale (VAS) and the Oswestry Low Back Pain Ques-tionnaire (OLBPQ). The authors reevaluated the patients at 3and 8 weeks (VAS) and 8 weeks (OLBPQ). At 3 weeks, 11 ofthe 15 patients who received botulinum toxin (73.3%) had50% pain relief versus 4 of 16 in the saline group. At weeks,9 of 15 in the botulinum toxin group and 2 of 16 in the salinegroup had relief. Repeat OLPBPQ at 8 weeks showed im-provement in 10 of 15 in the botulinum toxin group versus 3of 16 in the saline group. No patient experienced side effects.Conclude that paravertebral administration of botulinumtoxin A in patients with chronic low back pain relieved painand improved function at 3 and 8 weeks after treatment.

Comment by Miles Day, M.D.This study evaluates the use of botulinum toxin A in the

treatment of myofascial pain in patients with chronic low backpain. It’s conclusion is “Paravertebral administration of botu-linum toxin A in patients with chronic low back pain relievedpain and impoved function at 3 and 8 weeks after treatment”.While the results of this study are promising I agree with theauthors that the conclusion should be regarded with cautionbecause the sample size of patients studied was small. Mymain criticism is in the selection criteria the authors use in thiscriteria. As stated in the study six of the patients had a historyof disc disease and three had had discectomies five to eighteenyears prior to the study. As we in the pain field know, continu-ing pain after previous surgery can be secondary to multiplecauses including disc disease, epidural scaring, myofascialpain, and facet disease. These patients sometime have a hardtime delineating the amount of pain that is being generatedfrom each one of these potential causes of ongoing pain. Theresults of this study may have been better if the inclusion crite-ria eliminated patients with multiple pain generators and onlyincluded patients with myofacial pain.

Neurology (31)

Albert J. Tahmoush, R. J. Schwartzman, J. L. Hopp, J. R.Grothusen: Quantitative sensory studies in complex regionalpain syndrome type 1/RSD. (MCP Hahnemann University,Philadelphia, PA) Clin J Pain. 2000;16:340–344.

This study measured the warm, cold, heat-evoked pain thresh-old and the cold-evoked pain threshold in the affected area of16 control patients and patients with complex regional painsyndrome type 1/RSD (CRPSD1) to test the hypothesis that al-lodynia results from an abnormality in sensory physiology.The cold-evoked pain threshold in patients with CRPSD1/RSDwas significantly decreased when compared with the thresh-olds in control patients (ie, a smaller decrease in temperaturewas necessary to elicit cold-pain in patients with CRPSD1/RSD than in control patients). The heat-evoked pain thresholdin patients with CRPSD1/RSD was decreased significantly when

compared with thresholds in control patients. The warm-detec-tion and cold-detection thresholds in patients with CRPS1/RSD were similar to the thresholds in control patients. Con-clude that the study suggests that thermal allodynia in patientswith CRPS1/RSD resulted from decreased cold-evoked andheat-evoked pain thresholds. The thermal pain thresholds arereset so that non-noxious thermal stimuli are perceived to bepain (allodynia).

Neurology (32)

Matthias Schürmann, Georg Gradl, Ingrid Wizgal, MichaelaTutic, Christian Moser, Shanaz Azad, Antje Beyer: Clinicaland physiologic evaluation of stellate ganglion blockade forcomplex regional pain syndrome type I. (Ludwig-Maximilians-University, Munich, Germany) Clin J Pain. 2001;17:94–100.

Stellate ganglion blockade with local anesthetics was carriedout via an anterior paratracheal approach in 33 patients suf-fering from complex regional pain syndrome type I. Twenty-three (70%) of the 33 patients developed an increased in tem-perature difference between the treated hand and the con-tralateral hand of more than 1.5°C after the procedure, whichis a clinical sign of sympathicolysis. In 48% of these patients,the sympathetic function test showed an undisturbed sympa-thetic nervous function. In 10 patients, no significant increasein temperature difference was observed. Only 7 patients withpain relief revealed both clinical sympathicolysis and extin-guished sympathetic nerve function and qualified for sympa-thetically maintained pain. Conclude that clinical investigationis not reliable in the assessment of stellate ganglion blockade.Proof of sympathetically maintained pain based on pain reliefafter stellate ganglion blockade is not conclusive.

Neurology (33)

Gerald M. Ribbers, Henk J. Stam: Complex regional pain syn-drome type I treated with topical capsaicin: a case report.(Erasmus University Medical Center, Rotterdam, The Nether-lands) Arch Phys Med Rehabil. 2001;82:851–852.

This report described the case of a multitrauma patient whounderwent an amputation of the left arm and had a compli-cated left crural fracture with a delayed union. He was treatedin an inpatient setting for preprosthetic training for a myoelec-tric prosthesis and to regain walking abilities. After consolida-tion of the crural fracture, complex regional pain syndrometype I (CRPS I) developed in the left foreleg, which hinderedmobilization. Topical capsaicin 0.075% was prescribed and astress-loading mobilization schema was instituted. No othertreatment modalities directed at CRPS I were added. After 6weeks, no signs or symptoms of CRPS I were present and cap-saicin was discontinued. Capsaicin is a well-accepted and doc-umented treatment modality in neuropathic pain states such aspostherpetic neuralgia. However, it has rarely been describedin CRPS I. Capsaicin is discussed within the framework of re-cent insights in the neurobiology of nociception, and it is con-cluded that it may provide a theory-driven treatment for CRPS I,

Multidisciplinary Abstracts • 381

especially in the acute stage, which facilitates physical therapyand prevents peripheral and spinal sensitization.

Neurology (34)

J. J. Van Hilten, W. J. T. Van de Beek, A. A. Vein, J. G. VanDijk, H. A. M. Middelkoop: Clinical aspects of multifocal orgeneralized tonic dystonia in reflex sympathetic dystrophy.(Leiden University Medical Center, Leiden, The Netherlands)Neurology. 2001;56:1762–1765.

The authors of this article described 10 patients with reflex sym-pathetic dystrophy that progressed to a multifocal or general-ized tonic dystonia. The neuropsychologic profile was similar tothat of other patients with chronic pain, irrespective of its cause.The distribution pattern of dystonia, the stretch reflex abnor-malities, and the worsening of dystonia after tactile and audi-tory stimuli suggest impairment of interneuronal circuits at thebrainstem or spinal level. Antibody titers for glutamic acid de-carboxylase, tetanus, and Sjögren antigens were all normal.

Neurology (35)

Pere Domingo, Olga H. Torres, Josep Ris, Guillermo Vazquez:Herpes zoster as an immune reconstitution disease after initia-tion of combination antiretroviral therapy in patients with hu-man immunodeficiency virus type-1 infection. (Hospital de laSanta Creu I Sant Pau, Universitat Autònoma de Barcelona,Barcelona, Spain) Am J Med. 2001;110:605–609.

Of the 316 patients who initiated combination antiretroviraltherapy, 24 were treated for herpes zoster within 17 weeks ofstarting therapy. The characteristics of these cases were com-pared with those of a control group of 96 human immunodefi-ciency virus type-1 (HIV-1) infected patients, who were matchedby age, sex, plasma, HIV-1 RNA concentration and CD4 cellcounts, and length of follow-up. The incidence of herpes zosterassociated with combination antiretroviral therapy was 9 epi-sodes per 100 patient years. There were no significant differ-ences between cases and controls in age, sex, years of HIV in-fection, history of herpes zoster, previous acquired immunedeficiency syndrome, or baseline mean CD4 and CD8 cellcounts before beginning combination antiretroviral therapy.However, patients who developed herpes zoster had a signifi-cantly greater mean increase in the number of CD8 cells thandid controls. Conclude that the initiation of combination anti-retroviral therapy in HIV-1 infected patients was often associ-ated with the development of herpes zoster especially in thosewhom the number of CD8 cells increased after therapy.

Neurology (36)

Christian Chidiac, Jean Bruxelle, Jean-Pierre Daures, ThanhHoang-Xuan, Patrice Morel, Alain Leplège, Abdelkader ElHasnaoui, Cécile de Labareyre: Characteristics of patients withherpes zoster on presentation to practitioners in France. (Uni-versity Claude Bernard, Lyon, France) Clin Infectious Dis.2001;33:62–69.

There have been many epidemiological studies of chickenpox,but only a few of herpes zoster. We report data from an obser-vational study, conducted in France during a 1-year period, of9038 patients who presented with acute herpes zoster (n �8103) or postherpetic neuralgia (PHN) at the office practicesof 4635 general practitioners or dermatologists. The incidenceof herpes zoster in France was found to be similar to that in theliterature: from 1.4 to 4.8 cases per 1000 population per year.The patient profiles and clinical patterns delineated as well asthe management decisions made according to the type of treat-ing physician. The impact of herpes zoster on quality of lifewas evaluated on the basis of the Medical Outcome StudyShort Form 36 (MOS SF 36 scale, which is widely used for as-sessing quality of life in the field of health. This study providedreference data on the substantial deterioration in quality of lifeassociated with herpes zoster and PHN.

Neurology (37)

Helge Kasch, Kristian Stengaard-Pedersen, Lars Arendt-Nielsen,Troels Staehelin Jensen: Headache, neck pain, and neck mo-bility after acute whiplash injury: a prospective study. (AarhusUniversity Hospital, Denmark) Spine. 1994;26:1246–1251.

This article discussed a 6-month prospective study of neck mo-bility in patients with acute whiplash injury and a controlgroup with acute ankle distortion. The results of this study in-dicated that patients with whiplash injury had significantly re-duced flexion, extension, lateral flexion, and rotation of theneck as compared with patients with ankle distortion injury.Neck mobility, however, was similar in the 2 groups after 3months. Conclude that neck mobility is reduced immediatelyafter, but not 3 months after, a whiplash trauma. Headacheand neck mobility are related inversely and neck pain and neckmobility are related inversely during the first 6 months afteracute whiplash injury.

Neurosurgery (38)

M Sindou, P. Mertens, M. Wael: Microsurgical DREZotomy forpain due to spinal cord and/or cauda equina injuries: long-term results in a series of 44 patients. (University of Lyon,Lyon, France) Pain. 2001;92:159–171.

This article reported on the long-term results of the microsur-gical approach to the dorsal root entry zone (DREZotomy) ina series of 44 patients suffering from unbearable neuropathicpain secondary to spine injury. The follow-up ranged from 1to 20 years. The series included 25 cases with conus med-ullaris, 12 with thoracic cord, 4 with cauda equina and 3 withcervical cord injuries. Surgery was performed in 37 cases at thepathological spinal cord levels that corresponded to the terri-tory of the so-called “segmental pain,” and in 7 cases, on thespinal cord levels below the lesion for “infralesional pain,”syndromes. Regarding pain characteristics, a good result wasobtained in 88% of the cases with predominately paroxysmalpain as compared with 26% with continuous pain. There wereno perioperative mortalities. Morbidity included cerebrospinal

382 • multidisciplinary abstracts

fluid leak (3 patients), wound infection (2 patients), subcuta-neous hematoma (1 patient), and bacteremia (1 patient). Con-clude that the inclusion of DREZ-lesioning surgery in the neu-rosurgical armamentarium for treating “segmental” pain dueto spinal cord injuries is justified.

Comment by Ron Pawl, M.D., FACThis is a seminal report, because it provides long-term

(greater than 1 year, 71 months average) outcome from thedorsal root entry zone lesioning, at the site of and one levelabove and below the site of injury, for pain after spinal cord in-jury. This procedure was performed using a microsurgical opentechnique. Results were good (greater than 75% relief) in pa-tients with regional pain syndromes, in the body segments re-lated to the site of cord injury, that was paroxysmal pain, andafter conus medullaris lesions, which were the greatest numberof cases treated. Continuous pain, burning pain, and infrale-sional pain syndromes, below the site of the cord injury, werenot significantly benefited. Unfortunately, the authors did notreport on the psychological make-up of the patients, whichmight provide some insight into good versus bad outcome.

Neurosurgery (39)

Madjid Samii, Steffani Bear-Henney, Wolf Lüdemann, Mar-cos Tatagiba, Ulrike Blömer: Treatment of refractory pain af-ter brachial plexus avulsion with dorsal root entry zone lesions.(Medical School Hannover, Hannover, Germany) Neurosur-gery. 2001;48:1269–1275.

Forty-seven patients with intractable pain after traumatic cer-vical root avulsions were treated with dorsal root entry zonecoagulation between 1980 and 1998. The dorsal root entryzone coagulation procedure was performed 4 months to 12years after the trauma, and patients were monitored for up to18 years. Immediately after surgery, 75% of the patients expe-rienced significant pain reduction; this value was reduced to63% during long-term follow-up monitoring. Nine patientsexperienced major complications including subdural hemato-mas and motor weakness of the lower limb. Improved coagu-lation electrodes with thermistors that could produce smallerand more accurate lesion sizes, which were introduced in1989, significantly reduced the number of complications. Con-clude that long-term follow-up monitoring of patients who un-derwent the dorsal root entry zone coagulation procedure inthe cervical cord indicated that long-lasting satisfactory reliefis possible for the majority of individuals with acceptable mor-bidity rates.

Comment by Ron Pawl, M.D.This paper is important for several reasons. It provides a

long-term follow-up on patients suffering intractable pain af-ter cervical nerve root avulsion from the cord, and results ofdorsal root entry zone lesioning using the thermocoagulationtechnique, where lesions are made at 1 mm intervals coveringthe length of the cord and one level above and one below thelevels of the roots involved. Thirty-nine of 47 patients had63% reduction of pain in follow-up of 2 to 18 years (14 year

average). The authors also reported that 9 patients experi-enced major complications including subdural hematomas andlower extremity weakness, which they attribute to the elec-trodes used to make the lesions prior to 1989. Using an im-proved electrode since that time, they report fewer complica-tions. Also, the authors note no correlation between theduration of the pain, the time between the trauma and the sur-gery, and the time of onset of the pain after trauma with theoutcome of the surgery, indicating the procedure is effective,even when carried out years after the onset of the pain. Thislast concept puts a damper on the idea of centralized painmemory as the mechanism for the chronic pain.

Neurosurgery (40)

Volker M. Tronnier, Dirk Rasche, Jürgen Hamer, Anna-LenaKienle, Stefan Kunze: Treatment of idiopathic trigeminal neu-ralgia: comparison of long-term outcome after radiofrequencyrhizotomy and microvascular decompression. (Heidelberg Col-lege of Medicine, Heidelberg, Germany) Neurosurgery. 2001;48:1261–1267.

The purpose of this study was to evaluate the long-term out-come of patients after either percutaneous trigeminal rhizot-omy or microvascular decompression (MVD) for idiopathictrigeminal neuralgia at a single institution. Overall, the resultsof the study showed that there was a 50% risk of recurrence ofpain 2 years after percutaneous radiofrequency rhizotomy.Conversely, 64% of the patients who underwent MVD re-mained completely pain free 20 years postoperatively. Patientswithout sensory impairment after MVD were pain free signifi-cantly longer than patients who experienced postoperativelyhypesthesia or partial rhizotomy. Conclude that because it iscurative and nondestructive, MVD is considered the treatmentof choice for trigeminal neuralgia in otherwise healthy people.In this study, it was proved to be a more effective and long-lasting procedure for patients with typical trigeminal neuralgiathan radiofrequency rhizotomy. Patients without postopera-tive sensory deficit remained pain free significantly longer,which is a strong argument against the “trauma” hypothesis ofthis procedure.

Comment by Ron Pawl, M.D.This paper is noteworthy in that comparing the follow-up

on 225 of 378 patients who underwent microvascular decom-pression (MVD) with 206 of 316 who underwent radiofre-quency thermocoagulation (RFT), the RFT group stood a50% risk of recurrent pain by 2 years after the procedure,whereas 64% of those undergoing MVD were pain-free after20 years. Furthermore, after MVD, those patients with nopostoperative sensory deficit, measured with von Frey hairs,remained pain-free longer than those with a sensory deficit.This latter finding flies in the face of the concept that to be ef-fective, surgery for trigeminal neuralgia must damage thenerve. The whole concept of RF lesioning of the nerve is todamage it enough to deaden the trigger zone of the affectednerve branch. However, in this study it is noted that postoper-ative hypesthesia was only temporary after RF lesioning, which

Multidisciplinary Abstracts • 383

might well explain the high rate of pain recurrence in this se-ries. Although the long-term pain relief in the MVD group isexcellent, it must be weighed against the complications. In theMVD group, there were 3 mortalities, diminished hearing in5%, loss of hearing in 2.6%, facial paralysis in 4 patients, andtinnitus in 4 patients, none of which occurred in the RF group.

Oncology (41)

Edzard Ernst: Complementary therapies in palliative cancercare. (University of Exeter, Exeter, United Kingdom) Cancer.2001;91:2181–2185.

In this article several complementary therapies were identifiedas particularly relevant to palliative cancer care. Exemplarystudies were discussed. Although it was found that somepromising results for treatment existed, the article concludedthat there is a great deal of potential for complementary medi-cine in palliative care. The article also discussed the need formore rigorous research into the value of such treatments inpalliative and supportive cancer care.

Orthopedics (42)

Christopher J. Colloca, Tony S. Keller: Electromyographic re-flex responses to mechanical force, manually assisted spinalmanipulative therapy. (Logan College of Chiropractic, St.Louis, MO) Spine. 2001;26:1117–1124.

This is the first study demonstrating neuromuscular reflex re-sponses associated with mechanical force, manually assisted(MFMA) spinal manipulative therapy in patients with lowback pain. Noteworthy was the finding that such mechanicalstimulation of both the paraspinal musculature stimulationand spinous processes produced consistent generalized sEMGresponses. Identification of neuromuscular characteristics, to-gether with a comprehensive assessment of patient clinical sta-tus, may provide for clarification of the significance of spinalmanipulative therapy in eliciting putative conservative thera-peutic benefits in patients with pain of musculoskeletal origin.

Opthalmology (43)

Leonard Pek-Kiang Ang, Kah-Guan Au Eong, Su-Guan Ong:Herpes zoster ophthalmicus. (Singapore National Eye Center,Singapore) J Pediatric Ophthalmology Strabismus. 2001;38:174–176.

This case report discussed 2 children with herpes zoster oph-thalmicus as the first manifestation of varicella-zoster virus in-fection. Both children’s mothers had varicella while they werepregnant, but the children did not have a history of clinicalvaricella following birth. The authors concluded that the chil-dren were infected transplacentally with complete resolutionof the features of the disease at the time of delivery. Such casesof childhood herpes zoster without a history of clinical vari-cella infection are rare in literature.

Pharmacology (44)

Thomas P. Enggaard, Lars Poulsen, Lars Arndt-Nielsen, SteenHonoré Hansen, Inga Bjørnsdottir, Lars F. Gram, Søren H.Sindrup: The analgesic effect of codeine as compared to imip-ramine in different human experimental pain models. (Univer-sity of Southern Denmark, Odense, Denmark) Pain. 2001;92:277–282.

The hypoalgesic effect of single oral does of 100 mg imip-ramine and 125 mg codeineWas evaluated in this randomized,placebo-controlled experiment that included 18 healthy volun-teers. Pain tests were performed before and 90, 180, 270, 360,and 450 min after medication. The tests included determina-tion of pain tolerance thresholds to pressure, single electricalsural nerve stimulation, and to repetitive sural nerve stimula-tion. Codeine significantly increased pressure pain tolerance, paindetection and pain tolerance thresholds. It was concluded thatboth imipramine and codeine inhibit temporal pain summation,whereas only codeine reduces cold pressor pain. Pain summa-tion may be a key mechanism in neuropathic pain. Imipraminehas a documented effect on such pain conditions on temporalsummation. In addition, this study showed that codeine alsoinhibits temporal summation, which is in line with the clinicalobservations indicating that opioids relieve neuropathic pain.

Pharmacology (45)

M. M. Heinricher, J. C. Schouten, E. E. Jobst: Activation of brain-stem N-methyl-D-aspartate receptors is required for the analge-sic actions of morphine given systemically. (Oregon Health Sci-ences University, Portland, OR) Pain. 2001;92:129–138.

This study was designed to characterize the contribution ofN-methyl-D-aspartate (NMDA) and non-NMDA-mediated ex-citatory transmission within the rostral ventromedial medulla(RVM) to activation of brainstem inhibitory output neuronsand analgesia produced by systemic morphine administration.The results highlight 2 important aspects of RVM pain modu-latory circuits. First, morphine given systemically produces itanalgesic effect at least in part by recruiting an NMDA-medi-ated excitatory process to activate off-cells within the RVM.This excitatory process plays a role in the analgesic synergyproduced by simultaneous �-opioid activation at different lev-els of the neuraxis. Second, reflex-related activation of on-cellsis medicated by a non-NMDA receptor, and this activationdoes not appear to play a significant role in regulating reflexresponses to acute noxious stimuli. Excitatory amino acid-mediated excitation, thus, has 2 distinct roles within the RVM,activating off-cells and on-cells under different conditions.

Physical Medicine and Rehabilitation (46)

Debra L. Braverman, Curtis W. Slipman, David A. Lenrow:Using gabapentin to treat failed back surgery syndrome causedby epidural fibrosis: A report of 2 cases. (University of Penn-sylvania Health System, School of Medicine, Pennsylvania,PA). Arch Phys Med Rehabil. 2001;82:691–693.

384 • multidisciplinary abstracts

Failed back surgery syndrome (FBSS) is a long-lasting often dis-abling, and relatively frequent (5% to 10%) complication oflumdosacral spine surgery. Epidural fibrosis is among the mostcommon causes of FBSS, and it is often recalcitrant to treat-ment. Repeated surgery for fibrosis has only a 30% to 35% suc-cess rate, whereas 15% to 20% of patients report worsening oftheir symptoms. Long-term outcome studies focusing on phar-macologic management of chronic back pain secondary to epi-dural fibrosis are lacking in the literature. This report presented2 cases of severe epidural fibrosis managed successfully withgabapentin monotherapy. In both cases, functional status im-proved markedly and pain was significantly diminished. Gaba-pentin has an established, favorable safety profile and has beenshown to be effective in various animal models and human stud-ies of chronic neuropathic pain. Conclude clinicians should con-sider gabapentin as a pharmacological treatment alternative inthe management of FBSS caused by epidural fibrosis.

Physical Medicine and Rehabilitation (47)

Duk Hyun Sung, Tai Ryoon Han, Won-Hah Park, Heui JeBang, Jong-Moon Kim, Seung-Hyun Chung, Eung-Je Woo:Phenol block of peripheral nerve condition: titrating for opti-mum effect. (Sungkyunkwan University of Medicine, Seoul,Korea). Arch Phys Med Rehabil. 2001;82:671–676.

This experimental study was conducted to verify the dose-response relationship in phenol nerve block and to determinethe concentration and volume of phenol injectate required foreffective nerve conduction block. The test group consisted of71 New Zealand white rabbits. Group I (n � 48) received tib-ial nerve block by perineural injection (phenol, n � 40; saline,n � 8), Group II (n � 21) by submerging the nerve in phenolsolution. The 6 subgroups of Group I each received differentconcentrations (3%, 4%, 5%) and volumes (0.1 mL, 0.2 mL,0.3 mL). Compound muscle action potential (CMAP) and ten-sion of triceps surae muscles by electric stimulation of the sci-atic nerve were measured preintervention and at day 1, andweeks 1, 2, 4, and 8 postblock. Histologic studies were per-formed on 2 animals from group I. Two rabbits in Group Idied before results were obtained. In the remaining animals,CMAP amplitude reduced significantly as the volume of 5%phenol solution increased from 0.1 mL, 0.2 mL, to 0.3 mL. Ahigh concentration of phenol produced a more pronouncedconduction block; however, no significant difference existedamong the 3 concentrations. Submerged tibial nerve had agreater degree of conduction block than perineurally injectednerve. Depth of the degeneration area in nerve fascicle variedwith distance from the injection point. Conclude that the nerveblock effect of phenol can be titrated by adjusting the concen-tration and volume of phenol solution if the technique of ap-plication and localization of a block site are standardized.

Physical Medicine and Rehabilitation (48)

J. D. Rompe, C. Riedel, U. Betz, C. Fink: Chronic lateral epi-condylitis of the elbow: a prospective study of low-energyshockwave therapy and low-energy shockwave therapy plus

manual therapy of the cervical spine. (Johannes GutenbergUniversity School of Medicine, Mainz, Germany). Arch PhysMed Rehabil. 2001;82:578–582.

This prospective, matched single-blinded control trial com-pared the effects of extracorporeal shockwave therapy (ESWT)alone with a combination of ESWT and manual therapy of thecervical spine in treating chronic tennis elbow. Thirty patientswith unilateral chronic tennis elbow, an unsuccessful conser-vative therapy during the 6 months before referral, and clinicalsigns of cervical dysfunction were studied. Three times atweekly intervals all patients received 1000 shockwave im-pulses of an energy flux density of 0.16J/mm2 at the lateral el-bow. Additionally, they underwent manual therapy of the cer-vical spine and the cervicothoracic junction 10 times (GroupI). For each patient, a control matched by age and gender atfirst conservative treatment was drawn at random from 127patients who had undergone low-energy shockwave therapy inthe same unit in the past 3 years (Group II). Follow-up exami-nations took place at 12 weeks and at 12 months. Neithergroup differed statistically before the study, with a poor ratingfor all patients. At 12 months, there was still no significant dif-ference, with the outcome being excellent or good in 56% inGroup I and 60% in Group II. Each group showed significantimprovement compared with the respective prestudy evalua-tion. Conclude ESWT may be an effective conservative treat-ment method for unilateral chronic tennis elbow. The efficacyof additional cervical manual therapy for lateral epicondylitisremains questionable.

Physical Medicine and Rehabilitation (49)

Jaro Karppinen, Antii Malmivaara, Mauno Kurunlahti, EeroKyllönen, Tuomo Pienimäki, Pentti Nieminen, Arto Ohinmaa,Osmo Tervonen, Heikki Vanharanta: Periradicular infiltra-tion for sciatica: a randomized controlled trial. (UniversityHospital of Oulu, Helsinki, Finland). Spine. 2001;26:1059–1067.

In this study, 160 consecutive, eligible patients with sciaticawho had unilateral symptoms of 1 to 6 months duration, andwho never underwent surgery were randomized for a double-blinded injection with methylprednisolone bupivacaine combi-nation or saline. Objective and self-reported outcome parame-ters and costs were recorded at baseline, at 2 and 4 weeks, at 3and 6 months, and at 1 year. Recovery was better in the ste-roid group at 2 weeks for leg pain, straight leg raising, lumbarflexion, and patient satisfaction. Back pain was significantlylower in the saline group at 3 and 6 months. Sick leave andmedical costs were similar for both treatments, except for costof therapy visits and drugs at 4 weeks, which were in favor ofthe steroid injection. By 1 year, 18 patients in the steroid groupand 15 in the saline group underwent surgery. Conclude im-provement during the follow-up was found in both the methyl-prednisolone and saline groups. The combination of methyl-prednisolone and bupivacaine seems to have a short-termeffect, but at 3 and 6 months, the steroid group seems to expe-rience a “re-bound” phenomenon.

Multidisciplinary Abstracts • 385

Psychiatry (50)

Richard D. Jones: Depression and anxiety in oncology: the on-cologist’s perspective. (Beatson Oncology Center, Glasgow,United Kingdom). J Clin Psychiatry. 2001;62:52–55.

Depression and anxiety frequently occur in oncology patientsand have a significant impact on patient quality of life, healthcare utilization, and even disease outcome. Depression andanxiety are eminently treatable and, therefore, psychiatric as-sessment and appropriate intervention should form an integralcomponent of management strategy in patients with cancer. It

is essential that patients are recognized at an early stage, sothat resources can be targeted effectively at those most at riskof developing psychiatric morbidity. Evaluation techniquesthat can identify signs or symptoms of depression and anxietyand can be incorporated into the program of a busy oncologyclinic or in the primary care setting are, therefore, needed. Di-agnosis of depression and anxiety may be facilitated by usingprimary screening tools, such as family psychiatric history, lev-els of family support, and degrees of pain suffered by the pa-tient. This article considered the issues surrounding diagnosisof depression and anxiety in cancer patients and the benefits ofearly intervention from the point of view of the oncologist.