Neurolysis for meralgia paresthetica: an operative series of 45 cases

Clinical Insights and Optimization of Surgical Approach for Lateral Femoral Cutaneous Nerve Injury/Entrapment: A Comprehensive Analysis of 184 Cases

BACKGROUND

Entrapment or injury of the lateral femoral cutaneous nerve (LFCN) is being recognized with increasing frequency, often requiring a surgical approach to relieve symptoms. The presence of anatomic variations can lead to errors in diagnosis and intraoperative decision-making.

METHODS

This study presents the experience of a single surgeon (T.W.T.) in managing 184 patients referred with clinical issues related to the LFCN. A comprehensive review of these cases was conducted to develop a prospective surgical management algorithm. Data on the LFCN's anatomic course, pain relief outcomes, comorbidities, body mass index, and sex were extracted from patients' medical charts and operative notes. Pain relief was assessed subjectively, categorized into "excellent relief" for complete pain resolution, "good" for substantial pain reduction with some residual discomfort, and "failure" for cases with no pain relief necessitating reoperation.

RESULTS

The decision tree is dichotomized based on the mechanism of LFCN pathology: compression (requiring neurolysis) versus history of trauma, surgery, and/or obesity (requiring resection). Forty-seven percent of the patients in this series had an anatomic variation. It was found that failure to relieve symptoms of compression often indicated the presence of anatomic variation of the LFCN or intraneural changes consistent with a neuroma, even if adequate decompression was achieved. With respect to pain relief as the outcome measure, recognition of LFCN anatomic variability and use of this algorithm resulted in 75% excellent results, 10% good results, and 15% failures. Twenty-seven of the 36 failures originally had neurolysis as the surgical approach. Twelve of those failures had a second surgery, an LFCN neurectomy, resulting in 10 excellent, 1 good, and 1 persistent failure.

CONCLUSION

This article establishes an algorithm for the surgical treatment of MP, incorporating clinical experience and anatomical insights to guide treatment decisions. Criteria for considering neurectomy may include a history of trauma, prior local surgery, anatomical LFCN variations, and severe nerve damage due to chronic compression.

Right-sided meralgia paresthetica from lateral femoral cutaneous nerve neuroma

Meralgia Paresthetica (MP) causes outer thigh discomfort, numbness, and tingling. Compression or injury to the Lateral Femoral Cutaneous Nerve (LFCN), which gives sensory innervation to outer aspect of the thigh. It frequently gets impinged beneath the inguinal ligament resulting in in sensory impairment in the distribution of LFCN. Compression of the LFCN is a frequent cause of MP, whereas LFCN neuromas is a rare cause. This case report describes a unique case of Meralgia Paresthetica produced by a LFCN neuroma and enhances our knowledge of Meralgia Paresthetica.

Meralgia paresthetica

Meralgia paresthetica is a common but probably underrecognized syndrome caused by dysfunction of the lateral femoral cutaneous nerve. The diagnosis is based on the patient's description of sensory disturbance, often painful, on the anterolateral aspect of the thigh, with normal strength and reflexes. Sensory nerve conduction studies and somatosensory evoked potentials may be used to support the diagnosis, but both have technical limitations, with low specificity and sensitivity. Risk factors for meralgia paresthetica include obesity, tight clothing, and diabetes mellitus. Some cases are complications of hip or lumbar spine surgery. Most cases are self-limited, but a small proportion of patients remain with refractory and disabling symptoms. Treatment options include medications for neuropathic pain, neurolysis, neurectomy, and radioablation, but controlled trials to compare efficacy are lacking.

Treatment of idiopathic meralgia paresthetica – is there reliable evidence yet?

OBJECTIVE

Meralgia paresthetica is a common condition that is usually diagnosed by its classical clinical presentation and by exclusion of a spinal origin of pain, sensory loss, and/or paresthesias in the anterolateral thigh. Treatment modalities include conservative management, local injections, and surgical therapy. To date, no level 1 evidence exists about treatment options for idiopathic meralgia paresthetica. This review article aims to give a structured overview of epidemiology, history, anatomy, diagnostics, and treatment. It focuses on the existing literature and current developments in clinical management.

METHODS

A literature search on PubMed/MEDLINE was performed on 20 December 2021, yielding 1412 results. Abstracts were screened and classified in terms of epidemiology, anatomy, diagnostics, and treatment.

RESULTS

High-quality observational data that was included in recent meta-analyses showed satisfactory results for conservative management, injections, and surgical decompression or neurectomy, but there is some major methodological criticism. For idiopathic meralgia paresthetica, the results of surgical decompression have never been compared to those of neurectomy in a randomized setup. The only study protocol published so far does not consider any extended decompression techniques (dynamic, circumferent, proximal, and distal to the inguinal ligament). A multicenter, prospective design has never been proposed.

DISCUSSION

Reliable high-quality evidence on the treatment of idiopathic meralgia paresthetica is lacking at the current state, and challenges in clinical decision-making remain.

Meralgia Paresthetica

PURPOSE OF REVIEW

This review article summaries the epidemiology, etiology, clinical presentations, and latest treatment modalities of meralgia paresthetica, including the latest data about peripheral and spinal cord stimulation therapy. Meralgia paresthetica (MP) causes burning, stinging, or numbness in the anterolateral part of the thigh, usually due to compression of the lateral femoral cutaneous nerve (LFCN).

RECENT FINDINGS

There are emerging data regarding the benefit of interventional pain procedures, including steroid injection and radiofrequency ablation, and other interventions including spinal cord and peripheral nerve stimulation reserved for refractory cases. The strength of evidence for treatment choices in meralgia paraesthetica is weak. Some observational studies are comparing local injection of corticosteroid versus surgical interventions. However, more extensive studies are needed regarding the long-term benefit of peripheral and spinal cord stimulation therapy.

[Decompression of the lateral femoral cutaneous nerve of the thigh : Treatment of meralgia paresthetica]

OBJECTIVE

Treatment of non-responding pain to conservative treatment located at the anterolateral thigh with surgical decompression of the lateral femoral cutaneous nerve of the thigh (LFCN).

INDICATIONS

Compression syndrome of the LFCN; patients suffering from the following symptoms: pain (dysesthesia), numbness (paresthesia), hypersensibility to temperature (or temperature changes) along the course of the LFCN located at the anterolateral thigh.

CONTRAINDICATIONS

A new or recrudescent hernia with additional pain or recent laparoscopic hernia repair as a supposed iatrogenically induced compression of the LFCN.

SURGICAL TECHNIQUE

Dissection and release of the LFCN of connective tissue, scar tissue, bone rims, and retraction located along the passage underneath the inguinal ligament and distally.

POSTOPERATIVE MANAGEMENT

Suture removal after 10-14 days, no sports for 2 weeks. Physiotherapy if necessary. Neurography 4 months after surgery (obligatory if symptoms are persistent). The patient should be followed up for about 24 months.

RESULTS

Of the patients, 69% had a history of trauma or surgery, which were designated as the onset of pain. Of these patients, 78% had hip prostheses and 22% had previous falls. Postoperatively, a significant reduction of pain of 6.6 points on the numeric rating scale was observed. All other evaluated parameters also improved postoperatively. Patient satisfaction was high, with 86% reporting complete satisfaction, and 14% reporting partial satisfaction.

Meralgia paresthetica treated by injection, decompression, and neurectomy: a systematic review and meta-analysis of pain and operative outcomes

OBJECTIVE

Meralgia paresthetica is caused by entrapment of the lateral femoral cutaneous nerve (LFCN) and often presents with pain. Multiple treatment options targeting the LFCN can be pursued to treat the pain should conservative measures fail, with the most common options being injection, neurolysis, and neurectomy. However, their efficacy in causing pain relief and their clinical outcomes have yet to be directly compared. The aim of this study was to interrogate the contemporary literature and quantitatively define how these options compare.

METHODS

The electronic databases Ovid Embase, PubMed, SCOPUS, and the Cochrane Library were interrogated from inception to May 2020 following the PRISMA guidelines. Candidate articles were screened against prespecified criteria. Outcome data were abstracted and pooled by random-effects meta-analysis of proportions.

RESULTS

There were 25 articles that satisfied all criteria, reporting outcomes for a total of 670 meralgia paresthetica patients, with 78 (12%) treated by injection, 496 (74%) by neurolysis, and 96 (14%) by neurectomy. The incidence of complete pain relief was 85% (95% CI 71%-96%) after neurectomy, 63% (95% CI 56%-71%) after neurolysis, and 22% (95% CI 13%-33%) after injection, which were all statistically different (p < 0.01). The incidence of revision procedures was 12% (95% CI 4%-22%) after neurolysis and 0% (95% CI 0%-2%) after neurectomy, which were significantly lower than 81% (95% CI 64%-94%) after injection (p < 0.01). The incidences of treatment complications were statistically comparable across all three treatments, ranging from 0% to 5% (p = 0.34).

CONCLUSIONS

There are multiple treatment options to target pain in meralgia paresthetica. The incidence of complete pain relief appears to be the greatest among the 3 interventions after neurectomy, accompanied by the lowest incidence of revision procedures. These findings should help inform patient preference and expectations. Greater exploration of the anatomical rationale for incomplete pain relief after surgical intervention will assist in optimizing further surgical treatment for meralgia paresthetica.

Decompression and Neurolysis of the Lateral Femoral Cutaneous Nerve in the Surgical Treatment of Meralgia Paresthetica and the Results

Meralgia paresthetica (MP), also known as Bernhardt–Roth syndrome, is a peripheral neuropathy of the primary sensory lateral femoral cutaneous nerve (LFCN). Its diagnosis is challenging, because it can mimic other clinical conditions particularly associated with upper lumbar spine or pelvis. Patients present with pain and paresthesia over the anterolateral thigh. Diagnosis is usually based on clinical examination and is supported by sensory nerve conduction (SNC) studies. The initial treatment is always conservative. In limited number of patients who are refractory to conservative managements, surgical treatment via decompression/neurolysis or neurectomy is concerned. There is still no consensus on which surgical technique is the best and the first choice. We retrospectively analyzed the surgical outcomes of 12 nonobese patients who underwent decompression/neurolysis between the years 2013 and 2018. Bilateral SNC studies were performed in all cases which supported the diagnosis. We applied conservative treatments for 3 months in addition to the treatments previously applied in other centers. Surgery was recommended for the patients who were refractory to these treatments. Preoperative and postoperative pain levels during follow-up visits were evaluated with visual analogue scale (VAS). A retrospective analysis was performed on preoperative and postoperative 6th month VAS scores. The mean preoperative VAS value was 8.75 ± 0.62 and the postoperative VAS value at the sixth month was 1.17 ± 0.72. A significant reduction in the pain was shown (p < 0.05). Our surgical results showed that decompression/neurolysis of the LFCN should be concerned as the primary surgical approach to avoid negative outcomes of resection surgeries.

Fine architecture of the fascial planes around the lateral femoral cutaneous nerve at its pelvic exit: an epoxy sheet plastination and confocal microscopy study

OBJECTIVE

Meralgia paresthetica is commonly caused by mechanical entrapment of the lateral femoral cutaneous nerve (LFCN). The entrapment often occurs at the site where the nerve exits the pelvis. Its optimal surgical management remains to be established, partly because the fine architecture of the fascial planes around the LFCN has not been elucidated. The aim of this study was to define the fascial configuration around the LFCN at its pelvic exit.

METHODS

Thirty-six cadavers (18 female, 18 male; age range 38-97 years) were used for dissection (57 sides of 30 cadavers) and sheet plastination and confocal microscopy (2 transverse and 4 sagittal sets of slices from 6 cadavers). Thirty-four healthy volunteers (19 female, 15 male; age range 20-62 years) were examined with ultrasonography.

RESULTS

The LFCN exited the pelvis via a tendinous canal within the internal oblique-iliac fascia septum and then ran in an adipose compartment between the sartorius and iliolata ligaments inferior to the anterior superior iliac spine (ASIS). The iliolata ligaments newly defined and termed in this study were 2-3 curtain strip-like structures which attached to the ASIS superiorly, were interwoven with the fascia lata inferomedially, and continued laterally as skin ligaments anchoring to the skin. Between the sartorius and tensor fasciae latae, the LFCN ran in a longitudinal ligamental canal bordered by the iliolata ligaments.

CONCLUSIONS

This study demonstrated that 1) the pelvic exit of the LFCN is within the internal oblique aponeurosis and 2) the iliolata ligaments form the part of the fascia lata over the LFCN and upper sartorius. These results indicate that the internal oblique-iliac fascia septum and iliolata ligaments may make the LFCN susceptible to mechanical entrapment near the ASIS. To surgically decompress the LFCN, it may be necessary to incise the oblique aponeurosis and iliac fascia medial to the LFCN tendinous canal and to free the iliolata ligaments from the ASIS.

Dynamic decompression of the lateral femoral cutaneous nerve to treat meralgia paresthetica: technique and results

OBJECTIVE

The results of lateral femoral cutaneous nerve (LFCN) decompression to treat idiopathic meralgia paresthetica (iMP) vary widely. Techniques to decompress the LFCN differ, which may affect outcome, but in MP it is unknown to what extent. The authors present a new technique using dynamic decompression and discuss the outcomes.

METHODS

A retrospective cohort study was performed in a consecutive series of 19 cases. The goal of decompression was pain relief and recovery of sensation. The plane ventral to the LFCN was decompressed by cutting the fascia lata and the inferior aspect of the inguinal ligament. The plane dorsal to the LFCN was decompressed by cutting the fascia of the sartorius muscle. Subsequently, the thigh was brought in full range of flexion and extension/abduction. The authors identified and additionally cut fibers that tightened and caused compression at various locations of the LFCN during movement in all patients, referring to this technique as dynamic decompression. Postoperatively, an independent neurologist scored pain and sensation on a 4-point scale: completely resolved, improved, not changed, or worsened. Patients scored their remaining pain or sensory deficit as a percentage of the preoperative level. Statistical assessment was done using ANOVA to assess the association between outcome and duration of preoperative symptoms, BMI, and length of follow-up.

RESULTS

In 17 of the 19 cases (89%), the pain and/or paresthesia completely resolved. Patients in the remaining 2 cases (11%) experienced 70% and 80% reduction in pain. Sensation completely recovered in 13 of the 19 cases (69%). In 5 of the 19 cases (26%) sensation improved, but an area of hypesthesia remained. Four of these 5 patients indicated a sensory improvement of more than 75%, and the remaining patient had 50% improvement. Sensation remained unchanged in 1 case (5%) with persisting hypesthesia and mild hyperesthesia. There was no significant impact of preoperative symptom duration, BMI, and length of follow-up on postoperative outcome.

CONCLUSIONS

Dynamic decompression of the LFCN is an effective technique for the treatment of iMP. Most patients become completely pain free and sensation recovers considerably.

Transposition of the lateral femoral cutaneous nerve

OBJECTIVE

Meralgia paresthetica causes pain, burning, and loss of sensation in the anterolateral thigh. Surgical treatment traditionally involves neurolysis or neurectomy of the lateral femoral cutaneous nerve (LFCN). After studying and publishing data on the anatomical feasibility of LFCN transposition, the author presents here the first case series of patients who underwent LFCN transposition.

METHODS

Nineteen patients with meralgia paresthetica were treated in the Department of Neurological Surgery at University of Wisconsin between 2011 and 2016; 4 patients underwent simple decompression, 5 deep decompression, and 10 medial transposition. Data were collected prospectively and analyzed retrospectively. No randomization was performed. The groups were compared in terms of pain scores (based on a numeric rating scale) and reoperation rates.

RESULTS

The numeric rating scale scores dropped significantly in the deep-decompression (p = 0.148) and transposition (p < 0.0001) groups at both the 3- and 12-month follow-up. The reoperation rates were significantly lower in the deep-decompression and transposition groups (p = 0.0454) than in the medial transposition group.

CONCLUSIONS

Both deep decompression and transposition of the LFCN provide better results than simple decompression. Medial transposition confers the advantage of mobilizing the nerve away from the anterior superior iliac spine, giving it a straighter and more relaxed course in a softer muscle bed.

Surgical decompression of the lateral femoral cutaneous nerve (LFCN) for Meralgia paresthetica treatment: Experimental or state of the art? A single-center outcome analysis

Meralgia paresthetica (MP) is a rare lateral femoral cutaneous nerve-(LFCN)-mononeuropathy. Treatment for this disorder includes conservative and operative approaches; the latter is considered if conservative therapy fails. The most commonly used surgical approaches are decompression/neurolysis and avulsion/neurectomy. However, there are no definitive guidelines on the optimal surgical approach to be used. The purpose of this study was to evaluate the outcome of surgical decompression of the LFCN for the treatment of persistent MP with preservation of sensation along the distribution of the LFCN.We evaluated the outcomes of LFCN procedures performed between 2015 and 2016. A total of 16 surgical decompressions could be identified. Retrospective analysis of prospectively collected patient data was performed, as well as systematic evaluation of the postoperative course, with regular follow-up examinations based on a standardized protocol. Pain was analyzed using an NRS (numeric rating scale). Several postsurgical parameters, including temperature hypersensitivity and numbness in the LFCN region, were compared with the presurgical data.Sixty-nine percent of patients had histories of trauma or surgery, which were designated as the onset of pain. Of these patients, 78% had hip prostheses, 2 had previous falls. Postoperatively, a significant reduction of 6.6 points in the mean NRS pain value was observed. All other evaluated parameters also improved postoperatively. Patient satisfaction was high, with 86% reporting complete satisfaction, and 14% reporting partial satisfaction.Previous studies favor either avulsion/neurectomy as the preferred procedure for MP treatment, or provide no recommendation. Our findings instead confirm the decompression/neurolysis approach as the primary surgical procedure of choice for the treatment of MP, if conservative treatment fails.

Meralgia Paresthetica After Spine Surgery on the Jackson Table

Meralgia paresthetica is a non-life-threatening neurological disorder characterized by numbness, tingling, and burning pain over the anterolateral thigh due to impingement of the lateral femoral cutaneous nerve. This disorder has been seen in patients with diabetes mellitus and obesity, but has also been observed in patients after procedures such as posterior spine surgery, iliac crest bone grafts, lumbar disk surgery, hernia repair, appendectomies, and pelvic osteotomies that ultimately lead to compression or damage to the lateral femoral cutaneous nerve. Overall, permanent sequelae of meralgia paresthetica are rare, however, some cases do require intervention.

Evaluating the evidence: is neurolysis or neurectomy a better treatment for meralgia paresthetica?

BACKGROUND

Meralgia paresthetica is a mononeuropathy of the lateral femoral cutaneous nerve (LCFN). Surgical treatment involves transection or decompression of the LCFN. There is no clear consensus on the superiority of one technique over the other. We performed a systematic review of the literature to answer this question.

METHODS

Eligible studies included those that compared neurolysis versus neurectomy for the treatment of meralgia paresthetica after failure of conservative therapy. Our outcome of interest was resolution of symptoms. We performed a computerized search of MEDLINE (PubMed; all years) and of the Cochrane Central Register of Controlled Trials. Eligible studies had to include the words "meralgia paresthetica" and "surgery." All patients regardless of age were included, and there was no language restriction. We then reviewed the articles' titles and abstracts. All studies that compared neurolysis to neurectomy were included in the analysis.

RESULTS

Of the studies identified, none were randomized controlled trials. There were two German language articles that were translated by a third researcher. Each study was evaluated by two independent researchers who assigned a level of evidence according to American Association of Neurologist algorithm and also performed data extraction (neurolysis vs. neurectomy and resolution of pain symptoms). Each study was found to be level four evidence.

CONCLUSION

After reviewing the data, there was insufficient evidence to recommended one method of treatment over the other. This highlights the importance of keeping a national registry in order to compare outcomes between the two methods of treatment.

Technical feasibility of robot-assisted minimally-invasive neurolysis of the lateral cutaneous nerve of thigh: About a case

To limit the risk of iatrogenic neuroma and recurrence after surgical treatment of meralgia paresthetica, some authors have recently developed a technique of endoscopic neurolysis of the lateral cutaneous nerve of thigh (LCNT) below the level of the inguinal ligament. We report the case of a robot-assisted endoscopic technique underneath the inguinal ligament. A 62-year-old patient suffering of idiopathic meralgia paresthetica for the past 18 months received a Da Vinci robot-assisted minimally-invasive 10cm long neurolysis, of which 1/3 was situated above the level of the inguinal ligament and 2/3 below it. The patient was discharged the following day without complications. At 6-months follow-up the pain was rated 0/10 compared to 5/10 pre-operatively. Robot-assisted endoscopic neurolysis of the LCNT retains the advantages of conventional endoscopy and enables to approach the nerve in the most frequently compressed zone underneath the inguinal ligament. The three-dimensional view offered by robotic surgery facilitates the dissection. The superiority of this technique remains to be demonstrated by comparing it to conventional techniques.

Compression and entrapment neuropathies

Peripheral nerve entrapments are frequent. They usually appear in anatomical tunnels such as the carpal tunnel. Nerve compressions may be due to external pressure such as the fibular nerve at the fibular head. Malignant or benign tumors may also damage the nerve. For each nerve from the upper and lower limbs, detailed clinical, electrophysiological, imaging, and therapeutic aspects are described. In the upper limbs, carpal tunnel syndrome and ulnar neuropathy at the elbow are the most frequent manifestations; the radial nerve is less frequently involved. Other nerves may occasionally be damaged and these are described also. In the lower limbs, the fibular nerve is most frequently involved, usually at the fibular head by external compression. Other nerves may also be involved and are therefore described. The clinical and electrophysiological examination are very important for the diagnosis, but imaging is also of great use. Treatments available for each nerve disease are discussed.

Treatment for meralgia paraesthetica

BACKGROUND

Meralgia paraesthetica is a clinical syndrome for which a number of treatments are in common use, including conservative measures, injection of corticosteroid with local anaesthetic and surgery. We aimed to examine the evidence for the relative efficacy of these interventions. This review was first published in 2008. Searches were updated in 2010 and 2012.

OBJECTIVES

To assess the relative efficacy of commonly used treatments for meralgia paraesthetica.

SEARCH METHODS

We searched the Cochrane Neuromuscular Disease Group Specialized Register (1 October 2012), CENTRAL (2012, issue 9 in The Cochrane Library), MEDLINE (January 1966 to October 2012), EMBASE (January 1980 to October 2012) and CINAHL Plus (January 1937 to October 2012) for randomised controlled studies. Non-randomised studies were identified by searching MEDLINE (January 1966 to October 2012) and EMBASE (January 1980 to October 2012). We also inspected the reference lists of these studies.

SELECTION CRITERIA

We were unable to identify any randomised controlled trials (RCTs) or quasi-RCTs. We therefore looked for high quality observational studies meeting the following criteria: (1) At least five cases of meralgia paraesthetica. (2) Follow-up of at least three months after intervention (if any). (3) At least 80% of cases followed up.

DATA COLLECTION AND ANALYSIS

Three authors independently extracted relevant data from each study meeting the selection criteria and transferred into a data extraction form.

MAIN RESULTS

We found no RCTs or quasi-RCTs in the original review or updates in 20011 and 2012. Cure or improvement have been described in high quality observational studies: (1) A single study describes spontaneous improvement of meralgia paraesthetica in 20 (69%) of 29 cases. (2) Four studies evaluating the injection of corticosteroid and local anaesthetic found cure or improvement in 130 (83%) out of a combined total of 157 cases. (3) Surgical treatments have been found to be beneficial in 264 (88%) out of 300 cases treated with decompression (nine studies); and 45 (94%) out of 48 cases treated with neurectomy (three studies). (4) Ninety-nine (97%) out of 102 patients with iatrogenic meralgia paraesthetica recovered completely (three studies).

AUTHORS' CONCLUSIONS

In the absence of any published RCTs or quasi-RCTs, the objective evidence base for treatment choices in meralgia paraesthetica is weak. High quality observational studies report comparable high improvement rates for meralgia paraesthetica following local injection of corticosteroid and surgical interventions (either nerve decompression or neurectomy). However, a similar outcome has been reported without any intervention in a single natural history study.

Decision making in the surgical treatment of meralgia paresthetica: neurolysis versus neurectomy

BACKGROUND

Surgical treatment options for meralgia paresthetica include neurolysis and neurectomy procedures. Reported success rates for pain relief are generally higher after neurectomy, but an obvious disadvantage compared with neurolysis is the loss of sensation in the anterolateral part of the thigh. In this study we analyzed our results on pain relief after both procedures, and we determined the impact of loss of sensation with a questionnaire.

METHODS

Between 1999 and 2009, all patients with persistent symptoms of meralgia paresthetica who presented to our clinic after failure of conservative treatment were offered a neurectomy procedure. After this period, the surgical strategy was changed to first neurolysis followed by neurectomy in case of failure. We retrospectively analyzed our results for both strategies with a questionnaire that was focused on pain relief, numbness and the impact of numbness.

RESULTS

Ten patients underwent a neurolysis with a 60 % pain relief rate compared to 87.5 % of the eight patients that primarily underwent a neurectomy. Most neurectomy patients (62.5 %) were not hindered by the numbness, 25 % sometimes and only one patient was frequently bothered, but was still satisfied with the outcome. The failures of neurolysis were secondarily treated by neurectomy, which resulted in pain relief in three out of four patients.

CONCLUSIONS

This series confirms previous reports in the literature that have shown higher success rates for the neurectomy procedure. In addition, it shows that most patients are not bothered by the numbness following this procedure. These observations can be used in the surgical decision making for meralgia paresthetica.

Neurolysis for meralgia paresthetica

Objective

Meralgia paresthetica (MP) is a syndrome of pain and/or dysesthesia in the anterolateral thigh that is caused by an entrapment of the lateral femoral cutaneous nerve (LFCN) at its pelvic exit. Despite early accounts of MP, there is still no consensus concerning the effectiveness of neurolysis or transaction treatments in the long-term relief for medically refractory patients with MP. We retrospectively analyzed available long-term results of LFCN neurolysis for medically refractory MP in an effort to clarify this issue.

Methods

During the last 7 years, 11 patients who had neurolysis for MP were enrolled in this study. Nerve entrapment was confirmed preoperatively by electrophysiological studies or a positive response to local anesthetic injection. Decompression of the LFCN was performed at the level of the iliac fascia, inguinal ligament, and fascia of the thigh distally. The outcome of surgery was assessed 8 weeks after the procedure followed at regular intervals if symptoms persisted.

Results

Twelve decompression procedures were performed in 11 patients over a 7-year period. The average duration of symptoms was 8.5 months (range, 4-15 months). The average follow-up period was 33 months (range, 12-60 months). Complete and partial symptom improvement were noted in nine (81.8%) and two (18.2%) cases, respectively. No recurrence was reported.

Conclusion

Neurolysis of the LFCN can provide adequate pain relief with minimal complications for medically refractory MP. To achieve a good outcome in neurolysis for MP, an accurate diagnosis with careful examination and repeated blocks of the LFCN, along with electrodiagnosis seems to be essential. Possible variation in the course of the LFCN and thorough decompression along the course of the LFCN should be kept in mind in planning decompression surgery for MP.

Treatment of meralgia paresthetica with ultrasound-guided pulsed radiofrequency ablation of the lateral femoral cutaneous nerve

A 23-year-old female with an 18-month history of left anterolateral thigh paresthesias and burning pain consistent with meralgia paresthetica was referred to our clinic after failing trials of physical therapy, nonsteroidal anti-inflammatories, gabapentin, and amitriptyline. We performed 3 lateral femoral cutaneous nerve blocks with corticosteroid over a 4-month period; however, each block provided only temporary relief. As this pain was limiting the patient's ability to perform her functions as an active duty service member, we elected to perform a pulsed radiofrequency treatment of the lateral femoral cutaneous nerve with ultrasound guidance and nerve stimulation. After locating the lateral femoral cutaneous nerve with ultrasound and reproducing the patient's dysthesia with stimulation, pulsed radiofrequency treatment was performed at 42°C for 120 seconds. The needle was then rotated 180° and an additional cycle of pulsed radiofrequency treatment was performed followed by injection of 0.25% ropivacaine with 4 mg of dexamethasone. At 1.5 and 3 month follow-up visits, the patient reported excellent pain relief with activity and improved ability to perform her duties as an active duty service member. ▪

Meralgia paresthetica secondary to lipoma

Meralgia paresthetica (MP) consists of pain or dysthesia in the lateral thigh caused by entrapment of the lateral femoral cutaneous nerve (LFCN) underneath the inguinal ligament. The causes include iliac crest bone graft harvesting, seat belt injury associated with motor vehicle accident, diabetes mellitus, and trauma. The authors present the case of a 50-year-old woman who had a 1-year history of right-sided MP. The patient's history and the results of physical and radiological examinations were otherwise unremarkable except for the finding of a lipoma over the surface of the right sartorius muscle. Electrophysiological studies were interpreted as demonstrating peripheral neuropathy only. Conservative treatment, including heat or ice packing and local anesthetic and steroid injections, failed to control the patient's symptoms. Although sectioning or neurolysis of the LFCN appears to offer good-to-excellent results, the patient underwent excision of the lipoma. The symptoms resolved completely.

To the best of the authors' knowledge this is the first case of MP associated with compression caused by a lipoma. The authors conclude that lipoma compression can cause MP, and in such cases, total excision of the lipoma may resolve the condition.

Suprainguinal retroperitoneal approach for the successful surgical treatment of meralgia paresthetica

Object

Neurosurgical textbooks describe an infrainguinal approach as the standard or preferred option for the surgical treatment of meralgia paresthetica (MP), the most frequent entrapment neuropathy of the lower limb. However, inhomogeneous results led the authors to adopt a suprainguinal, retroperitoneal approach for decompression of the lateral femoral cutaneous nerve. In this paper the authors' aim was to study the outcome of patients harboring MP treated via this different surgical approach.

Methods

The outcome of 55 consecutive patients who underwent surgery for MP via the suprainguinal retroperitoneal approach during a 15-year period was ascertained through postal questionnaires (in 47 patients) and follow-up visits (in 8 patients). The male to female ratio was 1:0.67, and the mean patient age was 50 ± 12.9 years. The mean follow-up was 3.2 ± 3.3 years. Seven of the patients underwent bilateral surgery.

Results

Intraoperatively the lateral femoral cutaneous nerve was consistently found in close anatomical relationship to the anterior superior iliac spine, although some variations regarding the diameter, number of branches, and underlying pathological entity were observed. Eighty-seven percent of patients showed improvement (21 patients) or complete remission (27 patients) of painful dysesthesia in the anterolateral thigh, and 13% (7 patients) remained unchanged. In addition 82% had improvement (31 patients) or complete remission (14 patients) of hypesthesia, leaving 18% with unchanged (9 patients) or worsened (1 patient) hypesthesia. In the patient-evaluated group 66% (31 of 47) were completely satisfied with the outcome, 23% (11 of 47) were partially satisfied, and 11% (5 of 47) were not satisfied with the outcome. Two cases each of recurrence, seroma, wound infection, and 1 case of hematoma requiring revision were encountered as complications.

Conclusions

The suprainguinal retroperitoneal approach is a viable first-choice option for the surgical relief of MP.

High-resolution sonography of the palmar cutaneous branch of the median nerve

OBJECTIVE

The aim of this study was to describe the potential value of high-resolution sonography for evaluation of the palmar cutaneous branch of the median nerve (MN).

SUBJECTS AND METHODS

The volar wrists of 12 healthy volunteers and 22 consecutive patients with sensory deficit in the palmar triangle and thenar eminence suggesting neuropathy of the palmar cutaneous branch of the MN were examined with high-frequency sonography. Nine patients underwent carpal tunnel release, five had a history of penetrating trauma, six had symptoms suggesting concurrent carpal tunnel syndrome, one received surgery for palmaris tendon transfer, and one underwent resection of a ventral carpal ganglion cyst. Correlative 1.5-T MRI was performed in six patients.

RESULTS

In 83% of the healthy volunteers, 17-5-MHz sonography was able to identify the palmar cutaneous branch of the MN from its origin down to slightly distal to the wrist crease. In the patient group, sonography allowed detection of nerve abnormalities in 55% of the cases. Focal hypoechoic swelling of the nerve at the fascial crossing was observed in patients who had either concurrent carpal tunnel syndrome (four cases) or previous carpal tunnel release (three cases). Sonography performed after a penetrating trauma revealed nerve encasement by scar tissue (two cases) or complete transection of the nerve ending in a terminal neuroma (one case). Nerve transection secondary to resection of a ventral carpal ganglion cyst (one case) or to carpal tunnel release (one case) was also observed.

CONCLUSION

Sonography can identify the palmar cutaneous branch of the MN and characterize its abnormalities, providing unique information about this small nerve branch.

Treatment for meralgia paraesthetica

BACKGROUND

Meralgia paraesthetica is a clinical syndrome for which a number of treatments are in common use, including conservative measures, injection of corticosteroid with local anaesthetic and surgery. We aimed to examine the evidence for the relative efficacy of these interventions.

OBJECTIVES

To assess the relative efficacy of commonly used treatments.

SEARCH STRATEGY

We searched the Cochrane Neuromuscular Disease Group Trials Register (April 2008), MEDLINE (January 1 1966 to April 18 2008), EMBASE (January 1 1980 to May 12 2008) and CINAHL (January 1 1980 to May 12 2008) for randomised controlled studies. Non-randomised studies were identified by searching MEDLINE (January 1 1966 to April 18 2008) and EMBASE (January 1 1980 to May 12 2008). We also inspected the reference lists of these studies to identify further studies.

SELECTION CRITERIA

We were unable to identify any randomised controlled or quasi-randomised controlled trials. We therefore looked for high quality observational studies meeting the following criteria:(1) At least five cases of meralgia paraesthetica.(2) Follow-up of at least three months after intervention (if any).(3) At least 80% of cases followed up.

DATA COLLECTION AND ANALYSIS

Relevant data from each study meeting the selection criteria were extracted independently by all three authors and transferred into a data extraction form created for the review.

MAIN RESULTS

We found no randomised controlled or quasi-controlled trials. Cure or improvement have been described in high quality observational studies:(1) A single study describes spontaneous improvement of meralgia paraesthetica in 20 (69%) out of 29 cases.(2) Four studies evaluating the injection of corticosteroid and local anaesthetic found cure or improvement in 130 (83%) out of a combined total of 157 cases.(3) Surgical treatments have been found to be beneficial in 264 (88%) out of 300 cases treated with decompression (nine studies); and 45 (94%) out of 48 cases treated with neurectomy (three studies).(4) Ninety-nine (97%) out of 102 patients with iatrogenic meralgia paraesthetica recovered completely (three studies).

AUTHORS' CONCLUSIONS

In the absence of any published randomised controlled or quasi-randomised controlled trials, the objective evidence base for treatment choices in meralgia paraesthetica is weak. High quality observational studies report comparable high improvement rates for meralgia paraesthetica following local injection of corticosteroid and surgical interventions (either nerve decompression or neurectomy). However, a similar outcome has been reported without any intervention in a single natural history study.

Body mass index in meralgia paresthetica: a case-control study

OBJECTIVE

This case-control study explored the possibility of an association between body mass index (BMI) and meralgia paresthetica (MP).

PATIENTS AND METHODS

A total of 104 MP cases (33 women and 71 men, mean age 51.7 +/- 15.5 years) were matched for age and sex with 208 neurological and 208 dermatological controls. Differences between cases and controls were analyzed using the Wilcoxon and chi-squared tests. Odds ratio matched K controls (OR(MK)) and 95% confidence intervals (CI) were also calculated.

RESULTS

Mean BMIs were 28.0 +/- 4.9 for cases and 26.0 +/- 4.3 and 25.5 +/- 3.9 for neurological and dermatological controls, respectively. There were significant differences between absolute BMI of cases and neurological (P < 0.01) as well as dermatological controls (P < 0.001), and also significant associations between BMI categories and MP (P = 0.008 vs neurological controls and P = 0.004 vs dermatological controls). There were significant OR(MK) for obesity (BMI >or= 30) [OR(MK) vs neurological controls 2.04 (95% CI 1.13-3.67) and vs dermatological controls 2.5 (95% CI 1.4-4.5)].

CONCLUSION

High BMIs were associated with MP. Obesity doubled the risk of MP. MP may be related to increased pressure due to abdominal protrusion.

A novel approach to the diagnosis and management of meralgia paresthetica

OBJECTIVE

To review the results of conservative and surgical treatment of meralgia paresthetica (MP), with particular reference to the use of a simple clinical test for diagnosing this condition and the outcome of primary nerve decompression surgery.

METHODS

Records of all patients with a diagnosis of MP were reviewed. Information was obtained about clinical presentation and risk factors, diagnostic evaluation, management, and outcome. Actuarial analysis was used to determine the intervention-free interval after surgical decompression.

RESULTS

Between 2000 and 2005, MP was diagnosed in 45 patients. There were 27 men and 18 women, and the average age at presentation and duration of symptoms were 47 and 1.9 years, respectively. The pelvic compression test had a sensitivity of 95% and a specificity of 93.3% for this condition. Twenty-five patients were managed conservatively and 20 required operative intervention, which was bilateral in two patients. The average follow-up period was 25 months, and the actuarial 2- and 5-year intervention-free rates were 91 and 78%, respectively, with no specific risk factors for revision surgery.

CONCLUSION

The pelvic compression test is a sensitive and specific test for MP, helping to distinguish it from lumbosacral radicular pain. Most patients with this condition can be managed successfully with conservative measures, and those requiring surgery can be treated effectively with nerve decompression.

Meralgia paresthetica caused by hip-huggers in a patient with aberrant course of the lateral femoral cutaneous nerve

"Hip-huggers" may be a precipitating factor for meralgia paresthetica (MP), especially in thin persons with an aberrant pathway of the lateral femoral cutaneous nerve (LFCN). We describe a 25-year-old woman with a long-standing history of MP caused by an abnormal course of the LFCN and tight trousers, specifically hip-huggers. Ultrasonography was useful for detecting the lesion site and the abnormal pathway of the LFCN. After neurectomy of the LFCN, most of the symptoms of MP were relieved, but mild hypesthesia remained in the lateral thigh.

Meralgia paresthetica: A retrospective analysis of 79 patients evaluated and treated according to a standard algorithm

BACKGROUND

The efficacy of various treatment modalities in meralgia paresthetica (MP) is not established. We retrospectively evaluated the management of spontaneous MP (i.e. MP not secondary to trauma or surgery) according to a standard algorithm.

METHODS

Initial management included oral medications, rest, and reduction of aggravating factors. Non-responders underwent a diagnostic local anesthetic nerve block test. Patients who responded with transient symptomatic relief were treated by local infiltration of corticosteroids. Surgical intervention was reserved for patients with positive nerve block test, who did not respond to nonoperative measures.

RESULTS

A negative nerve block test ruled out the diagnosis of MP in 6/86 patients. Of 79 patients with MP, 21 responded to the initial nonoperative treatment and 48 patients responded to local corticosteroids. 3 of the remaining 10 patients underwent surgery (nerve transection 2, neurolysis 1). During an average of 3 (1-13) years of follow-up, symptoms consistent with MP did not recur in any of the 72 patients in whom symptoms had resolved after treatment.

INTERPRETATION

The algorithm used proved to be useful in the management of spontaneous meralgia paresthetica.

Meralgia paresthetica: Clinical and electrophysiological diagnosis in 120 cases

We report the results of clinical and electrophysiological examinations in 131 cases of meralgia paresthetica (MP) among 120 unselected patients, 69 men and 51 women, aged 15-81 years. All patients experienced permanent or intermittent pain, and all but one had permanent sensory impairment of the thigh. The lateral aspect of the thigh was solely involved in 88 cases and the anterior aspect was also or exclusively involved in 32 cases. The right thigh was involved 62 times and the left 58 times. Symptom duration varied from 2 weeks to 20 years. The initial diagnosis was meralgia paresthetica in 47 cases (39%), root disease in 35 cases, and osteoarthritis in 6 cases; no diagnosis was proposed in the 32 remaining cases. Two cases had undergone previous spine surgery for disk herniation, with no benefit. A precise cause could explain the lateral femoral cutaneous nerve (LFCN) lesion in 46 cases, the other 74 cases being considered idiopathic (25% of patients were obese). Only one case required surgery to relieve symptoms. LFCN conduction was studied orthodromically, distally from the anterior superior iliac spine. The side-to-side amplitude ratio (ssRatio) was greater than 2.3 in 118 of 120 patients (98.3%) and was a better index to confirm a lesion of the LFCN than SNAP amplitude, which was abnormal (less than 3 microV) in 88 cases (73.3%). Only two of the 11 bilateral cases had an ssRatio lower than 2.3 (they were both 2.0). An ssRatio of 2.3 or more and a SNAP amplitude lower than 3 microV provided a specificity of 98.75% or more. The mean axonal loss was 88%. These clinical and electrophysiological data highlight the central role the neurophysiologist should play in diagnosing MP by means of an LFCN conduction study.