An anomalous pseudoganglion associated with high division of sciatic nerve

Sciatic nerve (SN) is the thickest and longest nerve of the body. Deviations from the normal anatomical origin and level of bifurcation of SN have been frequently reported. In the present case, we are presenting a unique scenario of origin of terminal branches of the SN-tibial nerve (TN) and common peroneal nerve (CPN) in the pelvic region itself from divisions arising directly from the lumbosacral plexus. This variation was associated with origin of posterior femoral cutaneous nerve from the superior division of CPN with anomalous communicating branches between pudendal nerve and TN. The unique characteristics of the present case are the presence of 'pseudoganglion' found on the inferior division of TN. The present case stands out as the first of its kind to mention such pseudoganglion. Knowledge of some unusual findings like presence of pseudoganglion and intercommunications between nerves have clinical implications in anesthesiology, neurology, sports medicine, and surgery.

Origin, course, and distribution of the posterior femoral cutaneous nerve and the spatial relationship among its branches

This study aimed to elucidate the origin, course, and distribution of the branches of the posterior femoral cutaneous nerve, considering the segmental and dorsoventral compositions of the sacral plexus, including the pudendal nerve. The buttocks and thighs of five cadavers were analyzed bilaterally. The branches emerged from the sacral plexus, which was divided dorsally to ventrally into the superior gluteal, inferior gluteal, common peroneal, tibial, and pudendal nerves. It descended lateral to the ischial tuberosity and comprised the thigh, gluteal, and perineal branches. As for the thigh and gluteal branches, the dorsoventral order of those originating from the sacral plexus corresponded to the lateromedial order of their distribution. However, the dorsoventral boundary was displaced at the inferior margin of the gluteus maximus between the thigh and gluteal branches. The perineal branch originated from the ventral branch of the nerve roots. In addition, the pudendal nerve branches, which ran medially to the ischial tuberosity, were distributed in the medial part of the inferior gluteal region. These branches should be distinguished from the gluteal branches; the former should be classified as the medial inferior cluneal nerves and the latter as the lateral ones. Finally, the medial part of the inferior gluteal region was distributed by branches of the dorsal sacral rami, which may correspond to the medial cluneal nerves. Thus, the composition of the posterior femoral cutaneous nerve is considered necessary when considering the dorsoventral relationships of the sacral plexus and boundaries of the dorsal and ventral rami.

Diagnostic value of proximal cutaneous nerve biopsy in brachial and lumbosacral plexus pathologies

BACKGROUND

Brachial and lumbosacral plexopathies can result from numerous non-traumatic etiologies, including those of inflammatory, autoimmune, or neoplastic origin, that often require nerve biopsy for diagnosis. The purpose of this study was to evaluate the diagnostic efficacy of medial antebrachial cutaneous nerve (MABC) and posterior femoral cutaneous nerve (PFCN) nerve biopsies in proximal brachial and lumbosacral plexus pathology.

METHOD

Patients undergoing MABC or PFCN nerve biopsies at a single institution were reviewed. Patient demographics, clinical diagnosis, symptom duration, intraoperative findings, post-operative complications, and pathology results were recorded. Biopsy results were classified as diagnostic, inconclusive, or negative based on the final pathology.

RESULTS

Thirty patients undergoing MABC biopsies in the proximal arm or axilla and five patients with PFCN biopsies in the thigh or buttock were included. MABC biopsies were diagnostic in 70% of cases overall and 85% diagnostic in cases where pre-operative MRI also demonstrated abnormalities in the MABC. PFCN biopsies were diagnostic in 60% of cases overall and in 100% of patients with abnormal pre-operative MRIs. There were no biopsy-related post-operative complications in either group.

CONCLUSIONS

In diagnosing non-traumatic etiologies of brachial and lumbosacral plexopathies, proximal biopsies of the MABC and PFCN provide high diagnostic value with low donor morbidity.

An overlooked nerve in neuropathies associated with intragluteal injections: the posterior femoral cutaneous nerve

OBJECTIVE

The aim of this study was to investigate the frequency of posterior femoral cutaneous nerve (PFCN) lesions in patients referred to the electrophysiology laboratory with an initial diagnosis of sciatic nerve lesion following injection, and to create awareness that PFCN lesions can occur following intramuscular injections administered to the gluteal region.

METHODS

Fifty-seven patients who were referred to the electrophysiology laboratory because of injection neuropathy were identified from the hospital records. In addition to the routine electrophysiological examination, PFCN sensory conduction study was performed according to the technique of Dumitru and Nelson. The scores of the Hospital Anxiety and Depression Scale (HADS) and the Leeds Assessment of Neuropathic Symptoms and Signs Pain Scale were recorded for all participants.

RESULTS

Of the 21 participants who agreed to participate in the study, 2 patients were diagnosed with PFCN lesions, one of them had isolated complete PFCN lesion, and another had it accompanied by sciatic nerve lesion. Patients with PFCN lesions had a lower body mass index and a higher HADS score than patients with sciatic nerve lesions (p = 0.01, p = 0.04, respectively).

CONCLUSIONS

As correct diagnosis is the priority starting point for successful treatment, clinicians should plan examinations taking into consideration the fact that PFCN lesions can occur following gluteal region injection.

MRI-guided cryoablation of the posterior femoral cutaneous nerve for the treatment of neuropathy-mediated sitting pain

Neuropathy of the posterior femoral cutaneous nerve may manifest as pain and paresthesia in the skin over the inferior buttocks, posterior thigh, and popliteal region. Current treatment options include physical and oral pain therapy, perineural injections, and surgical neurectomy. Perineural steroid injections may provide short-term pain relief; however, to our knowledge, there is currently no minimally invasive denervation procedure for sustained pain relief that could serve as an alternative to surgical neurectomy. Percutaneous cryoablation of nerves is a minimally invasive technique that induces a sustained nerve conduction block through temporary freezing of the neural layers. It can result in long-lasting pain relief, but has not been described for the treatment of neuropathy-mediated PFCN pain. We report a technique of MR-guided cryoablation of the posterior femoral cutaneous nerve resulting in successful treatment of PFCN-mediated sitting pain. Cryoablation of the posterior femoral cutaneous nerve seems a promising, minimally invasive treatment option that deserves further investigation.