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

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.

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.

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.

Treatment of meralgia paresthetica (Lateral Femoral Cutaneous Neuropathy): A meta-analysis of ultrasound-guided injection versus surgery

PURPOSE

To compare ultrasound (US)-guided injections and surgery for the treatment of meralgia paresthetica (lateral femoral cutaneous neuropathy).

METHODS

Two reviewers, independently, up to 10 October 2020 retrieved Studies that assessed the outcome of US-guided injections and surgery for the treatment of meralgia paresthetica from major medical libraries. Predefined inclusion and exclusion criteria were adopted.

RESULTS

399 studies were initially found, and the meta-analysis was conducted on 10 studies for a total of 149 patients. US-guided injections were done in three studies, surgery in seven studies. N = 38 % (57/149) of patients were treated with US-guided injection and 62 % (92/149) were treated with surgery. After US-guided injections, 85 % (49/57) of patients were treated successfully, whereas 80 % (74/92) were treated with surgery successfully from the clinical point of view. Differences were not statistically significant even with a slight heterogeneity of studies and outcome pooled on random-effect model. No comparative cohort study or RCT was conducted.

CONCLUSION

This meta-analysis showed that there was no statistically significant difference in treatment of meralgia paresthetica with ultrasound-guided injection or surgery. A RCT to compare a standardized US-guided approach versus surgery is essential to compare these techniques properly.

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.