American Society for Peripheral Nerve

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Histopathologic analysis of the lateral femoral cutaneous nerve in patients with persistent symptoms of meralgia paresthetica
Godard C.W. de Ruiter, MD, PhD1; Joann Lim, Bsc1; Sjoerd G van Duinen, MD PhD2; (1)Haaglanden Medisch Centrum, The Hague, Netherlands, (2)Leiden University Medical Center, Leiden, Netherlands

Background

Decompression or neurolysis of the lateral femoral cutaneous nerve (LFCN) frequently is the surgical treatment of choice in patients with persistent symptoms of meralgia paresthetica. If neurolysis fails to relieve symptoms a neurectomy can be performed. At present it is not clear why decompression sometimes fails to alleviate pain symptoms. One explanation could be that chronic compression has led to irreversible changes within the nerve. The goal of the present study was to investigate if histopathologic changes can be identified in the resected LFCN from patients that underwent a neurectomy procedure. Potential correlations with the duration of symptoms and the patientís body mass index (BMI) were also investigated.

Methods

In 39 patients that underwent a neurectomy procedure the resected LFCN was analyzed at three levels: proximal, at and distal to the previous site of compression. In 10 patients the procedure was performed after failed neurolysis, in 29 patients as a primary procedure, either because the patient preferred this procedure (n= 23) or because the patient randomized for neurectomy in the STOMP trial (n= 6) *. Longitudinal sections, stained with H&E and Alcian blue, were analyzed for the presence of (1) a thickened perineurium, (2) fibrous nodules and (3) mucoid dispositions. The results were correlated with the duration of symptoms and the BMI.

Results

Intraneural changes occurred in various degrees in all patients. There were no significant differences in the occurrence between the different patient groups (either primary or secondary procedures). The intraneural changes also occurred equally at all three levels. There was a weak positive correlation between the occurrence of these changes and the duration of symptoms, particularly for patients with a BMI <30. The ratio of collagen was also higher in the latter group, while percentages mucoid depositions were larger in patients with a BMI >30.

Conclusions

Histopathological analysis of the resected LFCN in patients that underwent a neurectomy procedure showed changes in the perineurium thickness, the presence of fibrous nodules and mucoid depositions. Interestingly, different intraneural changes were found for patients with BMI < and >30, suggesting a difference in pathogenesis. Clinical results from the STOMP trial are needed to further investigate potential influences of duration of symptoms and BMI on the chance of failure of neurolysis.

* STOMP trial (Surgical Treatment Options for Meralgia Paresthetica) compares the effectiveness of the neurolysis and neurectomy procedure


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