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

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.

[A diagnostic algorithm for tunnel mononeuropathies management (consensus of experts)]

The expert consensus is aimed to develop an algorithm for the diagnosis and treatment of mononeuropathies for outpatient neurologists. Leading experts in the field of neurology have suggested workup options for certain types of tunnel mononeuropathies based on current data on the effectiveness and safety of various types of conservative and surgical treatment.

Meralgia Paresthetica: Relevance, Diagnosis, and Treatment

BACKGROUND

Pain and sensory disturbance in the distribution of the lateral femoral cutaneous nerve in the ventrolateral portion of the thigh is called meralgia paresthetica (MP). The incidence of MP has risen along with the increasing prevalence of obesity and diabetes mellitus and was recently estimated at 32 new cases per 100 000 persons per year. In this review, we provide an overview of current standards and developments in the diagnosis and treatment of MP.

METHODS

This review is based on publications retrieved by a selective literature search, with special attention to meta-analyses, systematic reviews, randomized and controlled trials (RCTs), and prospective observational studies.

RESULTS

The diagnosis is mainly based on typical symptoms combined with a positive response to an infiltration procedure. In atypical cases, electrophysiological testing, neurosonography, and magnetic resonance imaging can be helpful in establishing the diagnosis. The literature search did not reveal any studies of high quality. Four prospective observational studies with small case numbers and partly inconsistent results are available. In a meta-analysis of 149 cases, pain relief was described after infiltration in 85% of cases and after surgery in 80%, with 1-38 months of follow-up. In another meta-analysis of 670 cases, there was pain relief after infiltration in 22% of cases, after surgical decompression in 63%, and after neurectomy in 85%. Hardly any data are available on more recent treatment options, such as radiofrequency therapy, spinal cord stimulation, or peripheral nerve stimulation.

CONCLUSION

The state of the evidence is limited in both quantity and quality, corresponding to evidence level 2a for surgical and non-surgical methods. Advances in imaging and neurophysiological testing have made the diagnosis easier to establish. When intervention is needed, good success rates have been achieved with surgery (decompression, neurectomy), and variable success rates with infiltration.

Unusual causes for meralgia paresthetica: systematic review of the literature and single center experience

Meralgia paresthetica is often idiopathic, but sometimes symptoms may be caused by traumatic injury to the lateral femoral cutaneous nerve (LFCN) or compression of this nerve by a mass lesion. In this article the literature is reviewed on unusual causes for meralgia paresthetica, including different types of traumatic injury and compression of the LFCN by mass lesions. In addition, the experience from our center with the surgical treatment of unusual causes of meralgia paresthetica is presented. A PubMed search was performed on unusual causes for meralgia paresthetica. Specific attention was paid to factors that may have predisposed to LFCN injury and clues that may have pointed at a mass lesion. Moreover, our own database on all surgically treated cases of meralgia paresthetica between April 2014 and September 2022 was reviewed to identify unusual causes for meralgia paresthetica. A total of 66 articles was identified that reported results on unusual causes for meralgia paresthetica: 37 on traumatic injuries of the LFCN and 29 on compression of the LFCN by mass lesions. Most frequent cause of traumatic injury in the literature was iatrogenic, including different procedures around the anterior superior iliac spine, intra-abdominal procedures and positioning for surgery. In our own surgical database of 187 cases, there were 14 cases of traumatic LFCN injury and 4 cases in which symptoms were related to a mass lesion. It is important to consider traumatic causes or compression by a mass lesion in patients that present with meralgia paresthetica.

Meralgia Paresthetica Review: Update on Presentation, Pathophysiology, and Treatment

Purpose of Review

Meralgia paresthetica (MP) is a condition characterized by paresthesias, neuropathic pain, and alterations in sensorium of the anterolateral thigh secondary to impingement of the lateral femoral cutaneous nerve (LFCN). MP is generally diagnosed by clinical history and is often a diagnosis of exclusion. When diagnosis remains a challenge, diagnostic modalities such as ultrasound, MRI, electromyography, and nerve conduction studies have been utilized as an adjunct. This review summarizes the most recent medical literature regarding MP, its pathophysiology, presentation, and current treatment options.

Recent Findings

Treatment options for patients with MP range from lifestyle modifications and conservative management to surgical procedures. Initial management is often conservative with symptoms managed with medications. When conservative management fails, the next step is regional blocks followed by surgical management. The conflicting data for treatment options for MP highlight how the evidence available does not point to a single approach that's universally effective for treating all patients with MP.

Summary

Despite the apparent success at treating MP with regional blocks and surgical interventions, much remains to be known about the dosing, frequency, and optimal interventions due to the inconclusive results of current studies. Further research including randomized controlled trials are needed to better understand the most optimal treatment options for MP including studies with a larger number of participants.

Diagnosis and treatment of meralgia paresthetica between 2005 and 2018: a national cohort study

The prevalence of meralgia paresthetica (MP), which is caused by compression of the lateral femoral cutaneous nerve (LFCN), has been increasing over recent decades. Since guidelines and large-scale studies are lacking, there are substantial regional differences in diagnostics and management in MP care. Our study aims to report on current diagnostic and therapeutic strategies as well as time trends in clinical MP management in Germany. Patients hospitalized in Germany between January 1, 2005, and December 31, 2018, with MP as their primary diagnosis were identified using the International Classification of Disease (ICD-10) code G57.1 and standardized operations and procedures codes (OPS). A total of 5828 patients with MP were included. The rate of imaging studies increased from 44% in 2005 to 79% in 2018 (p < 0.001) and that of non-imaging diagnostic studies from 70 to 93% (p < 0.001). Among non-imaging diagnostics, the rates of evoked potentials and neurography increased from 20%/16% in 2005 to 36%/23% in 2018 (p < 0.001, respectively). Rates of surgical procedures for MP decreased from 53 to 37% (p < 0.001), while rates of non-surgical procedures increased from 23 to 30% (p < 0.001). The most frequent surgical interventions were decompressive procedures at a mean annual rate of 29% (± 5) throughout the study period, compared to a mean annual rate of 5% (± 2) for nerve transection procedures. Between 2005 and 2018, in-hospital MP care in Germany underwent significant changes. The rates of imaging, evoked potentials, neurography, and non-surgical management increased. The decompression of the LFCN was substantially more frequent than that of the LFCN transection, yet both types of intervention showed a substantial decrease in in-hospital prevalence over time.

Targeted dorsal root entry zone stimulation alleviates pain due to meralgia paresthetica

Objective.Meralgia paresthetica (MP) is a mononeuropathy of the exclusively sensory lateral femoral cutaneous nerve (LFCN) that is difficult to treat with conservative treatments. Afferents from the LFCN enter the spinal cord through the dorsal root entry zones (DREZs) innervating L2 and L3 spinal segments. We previously showed that epidural electrical stimulation of the spinal cord can be configured to steer electrical currents laterally in order to target afferents within individual DREZs. Therefore, we hypothesized that this neuromodulation strategy is suitable to target the L2 and L3 DREZs that convey afferents from the painful territory, and thus alleviates MP related pain.Approach.A patient in her mid-30s presented with a four year history of dysesthesia and burning pain in the anterolateral aspect of the left thigh due to MP that was refractory to medical treatments. We combined neuroimaging and intraoperative neuromonitoring to guide the surgical placement of a paddle lead over the left DREZs innervating L2 and L3 spinal segments.Main results.Optimized electrode configurations targeting the left L2 and L3 DREZs mediated immediate and sustained alleviation of pain. The patient ceased all other medical management, reported improved quality of life, and resumed recreational physical activities.Significance.We introduced a new treatment option to alleviate pain due to MP, and demonstrated how neuromodulation strategies targeting specific DREZs is effective to reduce pain confined to specific regions of the body while avoiding disconfort.

Successful application of spinal cord stimulation in a patient with refractory bilateral meralgia paresthetica

We present a 38-year-old morbidly obese male who presented with functionally limiting bilateral anterior thigh pain consistent with meralgia paresthetica. His symptoms had been unresponsive to conservative measures which included physical therapy, oral medications and multiple nerve blocks. Patient underwent a trial of spinal cord stimulation (SCS), experiencing 70% of pain relief. He then underwent permanent SCS implant. At subsequent follow-ups 3 and 6 months later, he continued to report 70% improvement of his pain, as well as improved function and quality of life. To our knowledge, this is only the second reported case of successful treatment of meralgia paresthetica with SCS, and the first in a morbidly obese patient.