Meralgia paresthetica (MP) is a mono-neuropathy result ing from the compression of the lateral femoral

cutaneous nerve (LFCN) as it crosses be-tween the anterior superior iliac spine (ASIS)and the inguinal ligament to enter the thigh(2). The nerve receives sensory input from theskin of the anterolateral thigh. Affectedpatients consequently experience a veryprominent painful dysesthesia and, less com-monly, vasomotor disturbance in the cuta-neous distribution of the nerve (5). This condi-tion can be confused with, and in a smallgroup of patients it can coexist with, lum-bosacral radicular pain. This can lead to diag-nostic difficulties in discerning the exact natureand cause of a patient’s symptoms which, inthe context of concurrent spinal stenosis, canlead to unnecessary spinal surgery being per-formed (10). Conversely, MP can arise de novoas a transient compression neuropathy result-

ing from patient positioning for spinal surgery(6). The apparent persistence of lower limbsymptoms in the early postoperative periodafter spinal surgery can be misconstrued bythe patient and the physician as a suboptimalsurgical outcome. As soon as it is suspected,MP can be diagnosed or excluded by electro-physiological studies of the LFCN (7).However, to our knowledge, there are no satis-factory, easy-to-apply clinical tests at present tohelp distinguish it from lumbosacral radicularpain to help direct the diagnostic effort.

Many patients can be managed conserva-tively with measures including avoidance oftightly fitting garments, analgesia, and physi-cal therapy (12). However, patients whosesymptoms persist despite maximal medicaltherapy require operative intervention. Atpresent, there is controversy regarding theoptimal treatment of this condition; two mainoperative approaches, primary nerve decom-

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CLINICAL STUDIES

S.A. Reza Nouraei, M.B.B.Chir.West London Neuroscience Centre,Charing Cross Hospital,London, United Kingdom

Bobby Anand, M.R.C.S.West London Neuroscience Centre,Charing Cross Hospital,London, United Kingdom

George Spink, M.R.C.S.West London Neuroscience Centre,Charing Cross Hospital,London, United Kingdom

Kevin S. O’Neill, F.R.C.S.(S.N.)West London Neuroscience Centre,Charing Cross Hospital,London, United Kingdom

Reprint requests:Kevin S. O’Neill, F.R.C.S.(S.N.),West London Neuroscience Centre,Charing Cross Hospital,London W6 8RF, United Kingdom.Email: koneill@hhnt.org

Received, June 7, 2006.

Accepted, December 5, 2006.

A NOVEL APPROACH TO THE DIAGNOSIS ANDMANAGEMENT OF MERALGIA PARESTHETICA

OBJECTIVE: To review the results of conservative and surgical treatment of meralgiaparesthetica (MP), with particular reference to the use of a simple clinical test for diag-nosing this condition and the outcome of primary nerve decompression surgery.METHODS: Records of all patients with a diagnosis of MP were reviewed. Informationwas obtained about clinical presentation and risk factors, diagnostic evaluation, man-agement, and outcome. Actuarial analysis was used to determine the intervention-freeinterval after surgical decompression.RESULTS: Between 2000 and 2005, MP was diagnosed in 45 patients. There were 27men and 18 women, and the average age at presentation and duration of symptomswere 47 and 1.9 years, respectively. The pelvic compression test had a sensitivity of95% and a specificity of 93.3% for this condition. Twenty-five patients were managedconservatively and 20 required operative intervention, which was bilateral in twopatients. The average follow-up period was 25 months, and the actuarial 2- and 5-yearintervention-free rates were 91 and 78%, respectively, with no specific risk factors forrevision surgery.CONCLUSION: The pelvic compression test is a sensitive and specific test for MP, help-ing to distinguish it from lumbosacral radicular pain. Most patients with this conditioncan be managed successfully with conservative measures, and those requiring surgerycan be treated effectively with nerve decompression.

KEY WORDS: Meralgia paresthetica, Nerve decompression, Peripheral neuropathy, Thigh pain

Neurosurgery 60:696–700, 2007 DOI: 10.1227/01.NEU.0000255392.69914.F7 www.neurosurgery-online.com

proximally with tenotomy scissors (Fig. 2). A 2.7-mm, 0-degreepediatric airway endoscope normally used for pediatric sinussurgery (Karl Storz, Tuttlingen, Germany) is sometimes used todemonstrate the nerve within the tunnel and ensure that thetunnel is fully decompressed. The nerve is then mobilized andthe fascial ridge between the ASIS and sartorius origin, overwhich the nerve bridges, is divided, decompressing the nerveposterolaterally. A probe is then introduced parallel to thenerve distally to identify any constricting distal aponeurotico-fascial tunnels. As soon as the nerve is fully decompressed, alimited neurolysis is performed, releasing any perifascicularconstrictions. The incision is then closed in the usual manner.

RESULTS

Clinical DataDuring the study period, MP was diagnosed in 45 patients.

The diagnosis was initially clinical; those patients who did notrespond to conservative treatment went on to undergo electro-physiological studies. There were 27 men and 18 women, andthe average age at presentation was 47 � 11 years (mean �standard deviation; range, 30–70 yr). Twenty-four patients hada significant history of lower back pain, 10 of whom had under-gone a previous spinal surgical procedure. Nine patients had alower abdominal procedure including appendicectomy or pre-vious acetabular surgery, and 10 patients had a body mass

pression or resection, have been advocated by different authors(11). In this study, we reviewed our experience with the man-agement of MP, with particular reference to the description andevaluation of a simple clinical test for diagnosing it in the clinic,and the long-term results of an operative approach aimed atpreserving thigh sensation.

PATIENTS AND METHODS

Details of all patients treated for MP by the senior author(KSO) were obtained from a prospectively collected database.Information about patient demographics, clinical presentation,diagnostic workup, conservative treatment, operative manage-ment, and postoperative complications were obtained. Infor-mation about symptom resolution, recurrence of symptoms,and any secondary surgical procedures were obtained fromfollow-up records. Data were presented either as means withstandard deviation or as percentages when appropriate. Thesymptom-free interval and time to reintervention were illus-trated using the Kaplan-Meier method, and the impact of dif-ferent preoperative variables on success or other outcomes ofthe operation was calculated with a multivariate Cox propor-tional hazards ratio model.

Pelvic Compression TestThe pelvic compression test is a simple and noninvasive test

for MP that, to our knowledge, has not been described previ-ously for this condition. It is based on the premise that as theLFCN is compressed by the inguinal ligament, relaxing the lig-ament should relieve pressure on the nerve and lead to a tempo-rary alleviation of symptoms. This can be achieved by laying thepatient on the examination couch in the lateral position on theirnonsymptomatic side. The patient is asked to focus on theirsymptoms and to place the ipsilateral hand on the symptomaticarea, which can enhance dysesthesia. The examiner then appliesa lateral compressive force on the pelvis as shown in Figure 1.This pressure is maintained for 45 seconds and the patient isasked to report any changes in the nature and severity of thesymptoms. Positive test results are considered as an improve-ment in patient symptoms. The sensitivity and specificity of thistest for MP was evaluated in a population of patients with elec-trophysiologically proven MP and in a second group of patientswith lumbosacral pain radiating to the lower limb.

Surgical Technique of LFCN DecompressionA 2- to 3-cm incision is placed inferomedial to the ASIS infe-

rior and along the line of the inguinal ligament. The investinglayer of fascia overlying the sartorius muscle is cleared andcarefully divided longitudinally (Fig. 2A). The subfascial planeis explored carefully to identify the nerve (Fig. 2B). The nerveis followed proximally to the inguinal ligament, and a bluntprobe is used to demonstrate the tunnel between ASIS, theinguinal ligament, and the origin of sartorius. Using an arteryclip, the inferior leaf of the inguinal ligament is lifted and, withthe nerve protected with a dissector, divided and splayed. Thisdecompresses the nerve anteromedially. This can be extended

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FIGURE 1. Illustrations demonstrating the pelvic compression test. A, thepatient is positioned on his or her side on an examination couch. B, down-ward pressure is applied and maintained for approximately 45 seconds.After 30 seconds, the patient is asked whether or not the symptoms haveeased. A positive response constitutes a positive test result.

A

B

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index of more than 30. The average duration of symptoms was1.9 � 2 years, and there were 24 and 18 right- and left-sidedlesions, respectively, and three patients with bilateral MP. Allpatients reported burning pain with varying degrees of numb-ness; 33 patients reported hypersensitivity in the distribution ofthe LFCN. Seven patients reported that their symptoms wereaffected by walking, but no other clear exacerbating or reliev-ing factors were identified in the remaining patients. Symptomsaffected sleep in 76% of all patients. The frequency of symp-toms between patients who were managed conservatively andthose who eventually required operation was compared withthe χ2 test and binary logistic regression There were no majordifferences between the two groups; however, patients whowere managed conservatively had a greater incidence of hyper-sensitivity as a predominant symptom. Conversely, patientswho required operative therapy were more likely to havesymptoms that significantly disturbed their sleep (Table 1).Figure 3 provides an overview of the management of patients,showing that, of the 45 patients who had MP at presentation, 22responded to conservative measures. The remaining 23 under-went electrophysiological confirmation of their diagnosisbefore further treatment. This consisted of therapeutic injec-tion of local anesthetic and steroids (bupivacaine and triamci-nolone acetate) in seven patients who had significant comor-bidity and 16 patients who underwent primary surgery.Therapeutic steroid and local anesthetic injection failed to

resolve symptoms in four patients, who then went on toundergo nerve decompressive surgery.

Pelvic Compression TestThe pelvic compression test was performed in all patients who

had abnormal nerve conduction studies and underwent surgeryfor MP as well as in 15 patients with sciatic pain in whom the

FIGURE 2. A, intraoperative photograph demonstrating that a constrictingaponeuroticofascial tunnel has been identified and elevated with a dissector. B,intraoperative photograph showing a constricting tunnel under the inguinalligament being divided with tenotomy scissors.

A

B

FIGURE 3. Flowchart demonstrating the management of MP in this series.

TABLE 1. Frequency of presenting symptomsa

Conservative Surgicalmanagement management

Age (yr � SD) 47 � 11 47 � 12Male sex (%) 64 50Duration of symptoms 1.9 � 1.4 2.2 � 1.8Chronic back pain (%) 56 48Sciatica 44 29Previous spinal surgery 16 30Clinical obesity 28 16Symptoms

Burning pain 84 100Hypersensitivity 96 65 (P � 0.02)Paresthesia 100 95

Aggravated by walking 32 21Affecting sleep 40 77 (P � 0.02)

aSD, standard deviation. All P values were greater than 0.05, except for those providedin the table.

diagnosis and management of this condition. It can frequentlycoexist with low back pain and radicular symptoms and can,therefore, present significant diagnostic and therapeutic chal-lenges (4). Our study demonstrates that the pelvic compressiontest is a useful and simple clinical test that can be used for screen-ing purposes and, as we have demonstrated, can be of particu-lar benefit in those patients in whom MP and low back paincoexist. The test is also useful in directing the initial diagnosticeffort and in the postoperative evaluation of patients who haveundergone spinal surgery. Given that patient positioning is arecognized risk factor for MP in a proportion of patients under-going spinal surgery (6), it is very important that this diagnosisbe considered when evaluating residual lower limb pain inpatients who have undergone spinal surgery. It is also useful forpatient selection purposes when nerve decompression surgery isconsidered. The test temporarily relieves compression at thelevel of the inguinal ligament, which surgery aims to achievepermanently. Therefore, it provides useful information aboutwhether or not nerve decompression is likely to be beneficial.

More than half of our patients were managed successfullywith conservative measures, including weight loss, avoidance oftightly fitting garments, and physiotherapy; a small groupderived lasting relief after local anesthetic and steroid injection.Patients who did not respond to these measures underwentnerve decompression surgery. There is a divergence of opinionin the literature about the optimal surgical management of thiscondition. Some authors advocate primary nerve decompres-sion as the optimal primary treatment for this condition,whereas others advocate primary nerve resection as the initialtherapy (11). We have found LFCN decompression to be aviable and successful first-line treatment, with a 2-year successrate of more than 90%, while allowing thigh sensation to bepreserved. It can be carried out successfully through a smallgroin incision; however, operative success depends both oncareful patient selection and adequate surgical decompressionof the nerve. Regarding patient selection, positive pelvic com-pression test results indicate that the nerve is likely to be com-pressed around its exit point into the thigh, and surgical decom-pression should, therefore, be of some benefit. In our practice,suspected nerve entrapment is electrophysiologically confirmedin all patients. Regarding surgical management, we find that thelateral femoral cutaneous nerve consistently courses within anaponeuroticofascial tunnel around its exit point into the thigh,an observation that is in keeping with anatomic studies of thecourse of the LFCN around its exit point (1, 2). We pay particu-lar attention to decompressing the nerve throughout the fulllength of this tunnel, as well as under the inguinal ligament,assisted by endoscopic vision when necessary. Using thisapproach, only three revisions needed to be performed, andonly one nerve needed to be transected. In those patients whorequired revision surgery, symptom relief was invariablyattained after the second procedure. This compares favorablywith the published literature, in which operative success rateshave been reported to range from 77 to 93% (3, 9, 11–13).

In conclusion, we recommend the use of the pelvic compres-sion test as a simple and noninvasive method of clinical screen-

diagnosis of MP was excluded electrophysiologically. The testresults were positive in 19 out of 20 patients with MP and nega-tive in 14 out of 15 patients with sciatic-type lower limb pain(P � 0.0001, χ2 test). This gave the test a sensitivity and speci-ficity of 95 and 93.3%, respectively. In calculating sensitivity andspecificity, we used only the population of patients who under-went surgical nerve decompression because these patients allhad electrophysiological confirmation of their diagnosis.

Surgical Treatment and OutcomeOf the patients treated operatively, all underwent LFCN

decompression surgery as described above in the Patients andMethods section. The average follow-up period was 25 months(range, 7–63 mo). There were two bilateral procedures, andthree revisions were required. Of these, two patients under-went a revision decompression, resulting in symptom resolu-tion in both patients; one patient required an LCFN transection,which again resolved his symptoms. All patients were dis-charged home the day after the procedure, and no immediatepostoperative complications were noted. We found no evidenceof wound infection or seroma formation in the early postoper-ative follow-up period. The actuarial likelihood of a patientremaining free of revision surgery at 2 and 5 years was 91 and79%, respectively (Fig. 4). A multivariate Cox proportional haz-ards ratio model could not identify any independent risk fac-tors for surgical reintervention. Variables used to construct theCox regression model were age and sex of the patient, presenceof back pain or previous spinal or groin surgery, side of thelesion, and the duration of symptoms.

DISCUSSION

MP is a compressive mononeuropathy of the lateral femoralcutaneous nerve of the thigh with a reported population inci-dence of 1 in 10,000 (8). It affects both sexes equally and typicallypresents with a burning pain and abnormal sensation over thedistribution of the nerve in the anterolateral compartment of thethigh (Fig. 1). In this study, we reviewed our experience with the

FIGURE 4. Line graph demonstrating the intervention-free interval aftersurgical decompression for MP (actuarial analysis).

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The authors describe a new clinical test, PCT, for the diagnosis ofMP. They report a sensitivity and specificity of 95 and 93%,

respectively for the PCT in establishing the diagnosis of MP. One ofthe authors’ major points is that the PCT is particularly valuable inhelping to distinguish MP from lumbar radiculopathy or other lum-bar spinal disorders. It seems to me that in its classic form, the symp-toms of MP are fairly stereotypical and the diagnosis should be fairlystraightforward for the astute clinician. Frankly, upper lumbarradiculopathy is relatively uncommon, and the characteristics ofradicular pain, its frequent association with lower back pain, and thepresence of other neurological findings should help distinguish thiscondition from MP in most cases.

Traditionally, the diagnosis of MP has been confirmed through elec-trophysiological testing. Side-to-side amplitude difference of the sen-sory nerve action potential of the lateral femoral cutaneous nerve hasbeen shown to be a more sensitive predictor of MP than the absoluteamplitude of the sensory nerve action potential. In fact, a side-to-sideamplitude ratio greater than 2.3 combined with a sensory nerve actionpotential amplitude of less than 3 microvolts has been shown to pro-vide a specificity in excess of 98% (1).

The authors’ series does reinforce the concept that most patientswith MP can be successfully managed with conservative therapy.However, patients who fail nonoperative measures should be con-sidered for surgical treatment. The major issue is whether or not toperform decompression with neurolysis or peripheral neurectomy.Indeed, there are proponents of both approaches. The authors’results of decompression and neurolysis are certainly impressive,and there are certainly other reports of excellent results with simpledecompression (2). In contrast, there are authors who have reportedsuperior results with nerve transaction (3). Most surgeons whoadvocate decompression cite the possibility of painful neuroma for-mation. However, in my experience, formation of a painful neu-roma is relatively rare in a pure sensory nerve that is surgicallytransected cleanly.

The authors seem to not place much emphasis on the use of diagnos-tic nerve blocks. However, it has been my experience that, if properlyperformed, repetitive diagnostic local anesthetic blockade of the lateralfemoral cutaneous nerve does carry some degree of prognostic valuefor surgical treatment, whether it be decompression or transection.

Richard K. OsenbachDurham, North Carolina

1. Seror P, Seror R: Meralgia paresthetica: Clinical and electrophysiological diag-nosis in 120 cases. Muscle Nerve 33:650–654, 2006.

2. Siu TL, Chandran KN: Neurolysis for meralgia paresthetica: An operativeseries of 45 cases. Surg Neurol 63:19–23, 2005.

3. van Eerten PV, Polder TW, Broere CA: Operative treatment of meralgia pares-thetica: Transection versus neurolysis. Neurosurgery 37:63–65, 1995.

Nouraei et al. have presented a large series of patients with MP.This is a large series that portrays the clinical presentation and sur-

gical management well. The use of the PCT, which is well described,seems to be a useful adjunct to diagnosis. The large clinical experienceand observations provided are a valuable addition to our literature.

Edward C. BenzelCleveland, Ohio

ing for meralgia paresthetica, and submit that surgical decom-pression of the nerve can be a highly successful first-linemethod of treatment in carefully selected patients.

REFERENCES1. de Ridder VA, de Lange S, Popta JV: Anatomical variations of the lateral

femoral cutaneous nerve and the consequences for surgery. J Orthop Trauma13:207–211, 1999.

2. Dias Filho LC, Valenca MM, Guimaraes Filho FA, Medeiros RC, Silva RA,Morais MG, Valente FP, Franca SM: Lateral femoral cutaneous neuralgia: Ananatomical insight. Clin Anat 16:309–316, 2003.

3. Ducic I, Dellon AL, Taylor NS: Decompression of the lateral femoral cuta-neous nerve in the treatment of meralgia paresthetica. J Reconstr Microsurg22:113–118, 2006.

4. Erbay H: Meralgia paresthetica in differential diagnosis of low-back pain.Clin J Pain 18:132–135, 2002.

5. Grossman MG, Ducey SA, Nadler SS, Levy AS: Meralgia paresthetica:Diagnosis and treatment. J Am Acad Orthop Surg 9:336–344, 2001.

6. Gupta A, Muzumdar D, Ramani PS: Meralgia paraesthetica following lumbarspine surgery: A study in 110 consecutive surgically treated cases. NeurolIndia 52:64–66, 2004.

7. Lagueny A, Deliac MM, Deliac P, Durandeau A: Diagnostic and prognosticvalue of electrophysiologic tests in meralgia paresthetica. Muscle Nerve14:51–56, 1991.

8. Latinovic R, Gulliford MC, Hughes RA: Incidence of common compressiveneuropathies in primary care. J Neurol Neurosurg Psychiatry 77:263–265,2006.

9. Nahabedian MY, Dellon AL: Meralgia paresthetica: Etiology, diagnosis, andoutcome of surgical decompression. Ann Plast Surg 35:590–594, 1995.

10. Seror P, Seror R: Meralgia paresthetica: Clinical and electrophysiological diag-nosis in 120 cases. Muscle Nerve 33:650–654, 2006.

11. van Eerten PV, Polder TW, Broere CA: Operative treatment of meralgia pares-thetica: Transection versus neurolysis. Neurosurgery 37:63–65, 1995.

12. Williams PH, Trzil KP: Management of meralgia paresthetica. J Neurosurg74:76–80, 1991.

13. Yang SH, Wu CC, Chen PQ: Postoperative meralgia paresthetica after poste-rior spine surgery: Incidence, risk factors, and clinical outcomes. Spine30:E547–E550, 2005.

COMMENTS

Reading this study dedicated to the diagnosis and treatment of mer-algia paraesthesica (MP), we appreciated that, for the first time, a

clinical test was introduced and applied to screen the patients indicatedfor surgical decompression. We remember the description of this pecu-liar clinical picture by Sigmund Freud at the beginning of the century(1). The father of psychoanalysis experienced pain within the anterolat-eral surface of the thigh owing to femorocutaneous nerve entrapment,but he could not demonstrate that his symptomatology was not a sortof psychogenic disease!

The pelvic compression test (PCT) proposed by the authors allows forthe true prediction of the outcome of nerve decompression as obtainedby the section of the inguinal ligament. If the causes of nerve compres-sion are different (i.e., ganglion cysts, posttraumatic fibrosis, etc.), thetest will also be negative in the presence of electromyographic signs ofnerve damage leading to more accurate diagnostic examinations andneuroimaging investigations. We will certainly perform this test in thenext patient we observe with pain in anterolateral surface of the thigh!

Angelo FranziniGiovanni BroggiMilan, Italy

1. Schiller F: Sigmund Freud’s meralgia paresthetica. Neurology 35:557–358, 1985.

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