0016-5107/92/3806-0757$03.00GASTROINTESTINAL ENDOSCOPYCopyright © 1992 by the American Society for Gastrointestinal Endoscopy

Status evaluation: sphincter of Oddimanometry

In order to promote the appropriate use of new or emerg­ing endoscopic technologies, the A/S/G/E Technology As­sessment Committee has developed a series of status evalu­ation papers. By this process, relevant information aboutthese technologies may be presented to practicing physiciansfor the education and care of their patients. In many cases,data from randomized controlled trials are lacking and onlypreliminary clinical studies are available. Practitionersshould continue to monitor the medical literature for sub­sequent data about the efficacy, safety, and socioeconomicaspects of the technologies.

BACKGROUND

The sphincter of Oddi (SO) is a short muscularsegment located at the terminal end of the pancreaticduct and common bile duct, which acts to regulate theflow of bile and pancreatic secretions into the duo­denum. Structural or functional disorders of thesphincter (SO dysfunction) have been implicated inthe etiology of various abdominal pain syndromes andSO pressure recordings (SO manometry) have beenutilized to further define and characterize these dis­orders.1,2

Severe upper abdominal pain of an intermittentrecurrent type which lasts from one to several hours,usually associated with prior food intake and some­times accompanied by vomiting, is characteristic ofthe pain pattern found in patients with pancreatic orbiliary disease. When this same symptom complexoccurs in patients with a history of prior cholecystec­tomy, and in the absence of objective recurrent biliarydisease, it is commonly referred to as post- cholecys­tectomy syndrome and may be due to sphincter ofOddi dysfunction. Patients with intact gallbladdersmay present with a similar pain syndrome. Biliaryobstruction due to retained common bile duct stonesmust be excluded before the diagnosis of sphincter ofOddi dysfunction can be entertained in the post-cho­lecystectomy patient with abdominal pain. Even then,it may be difficult to distinguish partial anatomicalobstruction of the sphincter of Oddi segment due toinflammatory stricture or scarring from functional(dyskinesia) disorders of the sphincteric zone.

Patients with biliary type pain have been classifiedinto three groups based on laboratory and ERCPfindings. Biliary type I patients have biliary-like painand three objective findings for biliary obstruction:abnormal liver function tests, prolonged common bileduct drainage time at ERCP, and a dilated common

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bile duct greater than 12 mm. Biliary type II patientswith biliary-like pain have one or two of the above­mentioned objective findings. Biliary type III patientshave biliary-like pain without any objective evidencefor biliary disease.3 Sphincter of Oddi manometry hasbeen used to diagnose, categorize, and plan therapeuticstrategies for these patient groups. Manometry hasalso been used to further define patients with recur­rent idiopathic pancreatitis.

PHYSIOLOGY OF THE SPHINCTER OF 0001

The SO is a 6- to 10-mm long muscular segmentcontaining the distal portions of the bile and pan­creatic ducts at their confluence of entry into thedescending duodenum. The sphincter is composed ofseveral smaller muscles, the sphincter choledochuswhich surrounds the distal common bile duct, thesphincter pancreaticus, which surrounds the lower endof the pancreatic duct and the sphincter ampullaewhich surrounds the common channel or ampulla. TheSO is felt to represent a physiologic dam or gatekeeperto regulate secretory flow of hepatic bile and pan­creatic juice into the duodenum by alterations in basalsphincter of Oddi tone and wave propagation duringfasting and eating. The sustained or basal pressure ofthe SO is usually 15 to 20 mm Hg above duodenalpressure (4 to 5 mm above common bile duct pressure).Basal pressures can be separated into the biliary orpancreatic sphincter component, depending on selec­tive cannulation. Phasic sphincter contractions (meanrate 4/min) are superimposed on basal pressure andcan normally reach 150 mm Hg. These phasic con­tractions correlate with the migrating myoelectriccomplex as it passes through the duodenum and theyfrequently are simultaneous or propagate antegradetoward the duodenum.4

,5 Manometric tracings showsimilar pressure values in patients with or without agallbladder. Cholecystokinin acts to relax the SO incorrelation with gallbladder contraction. Other drugsthat relax the SO include nitroglycerin, atropine, glu­cagon, and calcium channel blockers while narcoticsand alcohol increase the sphincter tone. Sphincter ofOddi dysfunction can include: increased basal pres­sure, increased phasic contraction amplitude or rate,an increase in the proportion of retrograde phasiccontractions, and an abnormal response to provoca­tive tests (i.e., increased basal pressure with cholecys­tokinin). In clinical studies, basal pressures have been

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the principal measurement used for therapeutic deci­sion making.

TECHNICAL CONSIDERATIONS

SO manometry utilizes pressure recording equip­ment and infusion systems such as those used forobtaining esophageal motility studies but differs inseveral respects, including the infusion rates and thenecessity for bubble-free, sterile water infusion. Inaddition, before each use, the infusion system must bedisinfected using 2% glutaraldehyde according tomanufacturer's specifications. Pressure recordings areaccomplished using a triple-lumen polyethylene cath­eter specially calibrated for use in biliary and pan­creatic ducts. The most distal orifice is 5 mm from theend of the catheter and the three orifices are spaced 2mm apart. Concentric marks starting at the mostdistal orifice are etched on the catheter surface topermit direct observation of the depth of the catheterinsertion into the SO. An aspirating manometry cath­eter should be strongly considered when the pancreaticduct sphincter is being evaluated as this special cath­eter has been associated with a decreased frequencyof post-procedure pancreatitis.

The endoscopist performing SO manometry shouldbe an expert in performing diagnostic and therapeuticERCP and should have the assistance of someonehighly skilled in manometric techniques to record thepressure measurements. The manometric catheter isadvanced through the biopsy channel of the duoden­oscope and stationed in the duodenum to record duo­denal pressure. The catheter is advanced into thecommon bile duct for baseline measurements andthen, slowly, pulled out or stationed in the SO zone torecord basal pressure and phasic contractions. Thecommon bile duct is usually preferentially cannulatedin the hope of avoiding pancreatitis. The correct cath­eter locations may be determined by aspirating bileinto the catheter tip or by injecting a small amount ofcontrast and utilizing fluoroscopic guidance to locatethe catheter position. The catheter passage throughthe sphincter may be facilitated by guidewire place­ment.

SO manometry differs from standard ERCP as itnecessitates a two-team approach, one involved in thetechnical aspects of ERCP and the other involving thetechnical and interpretive aspects of the sphincterpressure recordings. These two teams must maintaina continuous dialogue during the pressure recordingperiod to coordinate the various technical aspects ofERCP, such as the location of the catheter in thesphincter zone, with the pressure recordings. Thus,SO manometry requires more personnel than are nec­essary for standard ERCP. The additional personnelshould be responsible only to obtain accurate pressurerecordings and not be responsible for nursing duties.SO manometry also requires a time commitment thatis separate or in addition to diagnostic and therapeutic

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ERCP. Patient compliance may be difficult becauseconscious sedation must be attained without the useof narcotics. The technical aspects of the proceduremay be further compromised by the inability to useatropine or glucagon to decrease duodenal motility.Because of problems with adequate sedation, technicaldifficulties, and possible sphincteric pathology, thefailure rate of SO manometry may be high. It shouldalso be noted that SO manometry during ERCP onlymeasures pressures for short periods of time (minutes)and may not be representative of overall motilitycompared with longer measurement times with. othertechniques.7 Interobserver variation in manometrictracing interpretation is an additional concern whichhas been noted.!

INDICATIONS AND EFFICACY

Available data suggests that SO dysfunction mayplay an etiologic role in certain patients with biliarytype pain or idiopathic pancreatitis.! The primaryindication for SO manometry is to evaluate patientswith these pain syndromes. A variety of SO mano­metric abnormalities have been described in such pa­tients and as many as 41% of patients with unex­plained abdominal pain after cholecystectomy haveabnormal sphincter motility studies.8 An elevatedbasal sphincter pressure appears to be the most con­sistent and reproducible abnormal manometric find­ing.9 Basal pressures greater than 40 mm Hg aregenerally considered to be abnormal. Abnormal motil­ity studies are more frequently found in patients withobjective findings of abnormal biliary emptying suchas delayed contrast drainage time (over 45 min) duringERCP.8

Clinical classifications incorporating SO manome­try results have been developed to try to determinediagnostic categories of patients that could benefitfrom specific therapeutic interventions such assphincterotomy. SO manometry has been applied tothe three previously described groups of patients withbiliary type pain and correlated with their therapeuticresponse to endoscopic sphincterotomy. The biliarytype I group has elevated basal sphincter pressures inup to 90% of patients3 and sphincterotomy appears tobe very effective in improving symptoms and otherobjective parameters. Thus, SO manometry is consid­ered optional and not mandatory for therapeutic de­cision making about patients in this group.

Abnormal basal sphincter pressures are noted inapproximately 50% of biliary type II patients. Patientsin this group who had an elevated basal SO pressuregreater than 40 mm Hg and underwent sphincterot­omy demonstrated significant improvement (91 %) insymptoms and objective findings at follow-up com­pared with a 25% rate of improvement in patientswith high basal pressure who had a sham sphincter­otomy. In patients with normal SO pressures, responseto sphincterotomy was also lower (42%) and similar

GASTROINTESTINAL ENDOSCOPY

to that after the sham procedure (33% ).10 In the biliarytype III group, manometric abnormalities have beenvariably found in 7 to 55% of patients who presumablyhave primary sphincter of Oddi dyskinesia as the basisfor their symptoms. Overall, in biliary type III pa­tients, SO dysfunction appears to be less common andthe response to various therapies has not been com­pletely delineated.

Thus, SO manometry would appear to be mostuseful to diagnose and select group II or III patientswho are most likely to respond to sphincterotomy.10. 11

Preliminary data suggest that SO manometry mayalso be helpful in defining a group of patients withidiopathic recurrent pancreatitis who may respond toendoscopic sphincterotomy or surgical sphinctero­plasty.12

SAFETY

SO manometry has the same potential for compli­cations as ERCP but pancreatitis appears to occur ata higher rate than for diagnostic ERCP.13 Factors thatmay improve safety include: limiting SO total perfu­sion/recording time to 1 to 2 min and studying onlythe biliary segment of the SO rather than the pan­creatic segment; if the pancreatic portion of thesphincter is to be evaluated, use of a modified aspir­ating catheter may be most desirable.14

FINANCIAL CONSIDERATIONS

The cost of equipment used in the performance ofSO manometry includes a multichannel recorder uti­lizing a hydraulic-capillary infusion system (approxi­mately $25,000 to 30,000). Perfusion catheters cost upto $150 per reusable catheter. Facility use fees may behigher than for standard ERCP because of the needfor more personnel and additional procedure time.CPT code 43263 is used for "pressure measurement ofSO motility."

DIAGNOSTIC ALTERNATIVES

The morphine-postigmine provocative test has beenutilized to diagnose SO dysfunction, but the criteriafor abnormality varies and the value of this test iscontroversial.15 Quantitative hepatobiliary scintigra­phy and fatty-meal sonography have been utilized asnon-invasive methods for evaluating patients withsuspected partial common bile duct obstruction, in­cluding patients with SO dysfunction. When thesetests have been used in combination they have showngood sensitivity and specificity but only limited dataabout them are thus far available.16

SUMMARY

SO manometry appears to be helpful in defining agroup of patients with biliary pain or idiopathic recur­rent pancreatitis who may benefit from endoscopic orsurgical treatment. It is a procedure that requires

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considerable time and endoscopic expertise along withknowledge of the manometric interpretation ofsphincter of Oddi dysfunction. The diagnostic accu­racy of SO manometry and criteria for basing thera­peutic decisions on manometric findings need furtherstudy and verification.

Prepared by:Technology Assessment Committee

David A. Gilbert, MD, ChairmanAnthony J. DiMarino, MD

Dennis M. Jensen, MDRonald Katon, MD

Michael B. Kimmey, MDLoren A. Laine, MD

Bruce V. MacFadyen, MDPatrice A. Michaletz-Onody, MD

Gary Zuckerman, DO

REFERENCES

1. Cattau E. Biliary and pancreatic manometry. In: Barkin JS,O'Phelan CA, eds. Advanced therapeutic endoscopy. New York:Raven Press, 1990:249-57.

2. Raddawl H, Geenen J, Hogan W, et al. Pressure measurementsfrom biliary and pancreatic segments of sphincter of Oddi:comparison between patients with functional abdominal pain,biliary or pancreatic disease. Dig Dis Sci 1991;36:71-4.

3. Geenen JE, Hogan WJ, Dodds WJ. SphincterofOddi. In: SivakMV Jr., ed. Gastroenterologic endoscopy. Philadelphia: WBSaunders, 1987:735-51.

4. Guelrud M, Mandoza S, Rossiter G, et al. Sphincter of Oddimanometry in healthy volunteers. Dig Dis Sci 1990;35:38-46.

5. Goff J. The human sphincter of Oddi. Physiology and patho­physiology. Arch Intern Med 1988;148:2673-7.

6. Albert M, Steinberg W, Irani S. Severe acute pancreatitiscomplicating sphincter of Oddi manometry. Gastrointest En­dosc 1988;34:342.

7. Akita Y, Nimura Y, Yasui A. Percutaneous transhepatic ma­nometry of sphincter of Oddi. Dig Dis Sci 1991;36:1410-7.

8. Meshkinpour H, MoUot M. Sphincter of Oddi dysfunction andunexplained abdominal pain: clinical and manometric study.Dig Dis Sci 1992;37:257-61.

9. Thune A, Scicchitano J, Roberts-Thomson I, et al. Reproduci­bility of endoscopic sphincter of Oddi manometry. Dig Dis Sci1991;36:1401-5.

10. Geenen J, Hogan W, Dodds W, et al. The efficacy of endoscopicsphincterotomy after cholecystectomy in patients with sphinc­ter of Oddi dysfunction. N Engl J Med 1989;320:82-7.

11. Sherman S, Lehman G, Silverman W, et al. Efficacy of endo­scopic sphincterotomy and surgical sphincteroplasty for pa­tients with sphincter of Oddi dysfunction: randomized prospec­tive study [Abstract]. Gastrointest Endosc 1991;37:249.

12. Venu R, Geenen J, Hogan W, et al. Idiopathic recurrent pan­creatitis. An approach to diagnosis and treatment. Dig Dis Sci1989;34:56-60.

13. King C, Kalvaria I, Sninsky C. Pancreatitis due to endoscopicbiliary manometry: proceed with caution. Gastroenterology1988;94:A227.

14. Lehman G. Endoscopic sphincter of Oddi manometry: a clinicalpractice and research tool. Gastrointest Endosc 1991;37:490-2.

15. Gregg J. Function and dysfunction of the sphincter of Oddi. In:Jacobson I, ed. Current topics in gastroenterology: ERCP, di­agnostic and therapeutic applications. New York: Elsevier1990:139-70.

16. Darweesh R, Dodds W, Hogan W, et al. Efficacy of quantitativehepatobiliary scintigraphy and fatty-meal sonography for eval­uating patients with suspected partial common duct obstruc­tion. Gastroenterology 1988;94:779-86.

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