Comparison of Isolated Sciatic Nerve and Sacral Nerve Root Endometriosis: A Review of the Literature.

OBJECTIVE: This review aimed to compare isolated sciatic and sacral nerve root endometriosis in terms of anatomic distribution, patients' symptoms and history, diagnostics, treatments, and outcomes. DATA SOURCE: We searched PubMed, MEDLINE, Web of Science, and Embase from inception to October 2021 using a combination of keywords including "sciatic nerve endometriosis," "sacral nerve root endometriosis," and associated Medical Subject Headings. Relevant publications and references were also checked for further articles. METHODS OF STUDY SELECTION: Two independent researchers performed the study selection. We included all original research articles, case reports, and case series in English that reported on the isolated sciatic nerve and sacral nerve root endometriosis. TABULATION, INTEGRATION, AND RESULTS: The initial search identified 92 articles, and 40 articles, mostly case reports and case series, were included. The review included 362 patients: with 256 and 106 patients in the sacral and the sciatic groups, respectively. In both groups, most patients had right-sided endometriosis. In the sciatic group, most of the patients presented with foot drop, leg motor weakness, and sciatic dermatome hypoesthesia. The frequencies of all these symptoms were significantly higher in the sciatic group (all p <.001). By contrast, in the sacral group, most of patients presented with pudendal neuralgia (p <.001). Intraoperative, early, late, and 1-year postoperative complications did not differ significantly between the 2 groups. CONCLUSION: This study indicated that isolated sciatic and sacral nerve root endometrioses were more common on the right side. Laparoscopic surgery was more commonly performed over traditional open or transgluteal surgery techniques. Sacral nerve root endometriosis is often accompanied by deep infiltrating endometriosis. Magnetic resonance imaging and myelography may be useful diagnostic tools in the preoperative workup. There was usually no significant improvement after surgery in cases of isolated sciatic nerve endometriosis presenting with foot drop.

Foot drop as the initial symptom caused by thoracic disc herniation.

BACKGROUND: Foot drop is a syndrome resulting from weakness or paralysis of the tibialis anterior muscle. Some patients with thoracic disc herniation seek medical help complain of foot drop as the initial symptom. The study investigated the clinical characteristics of these patients and clarified the clinical efficacy after treatment. METHODS: A total of 13 patients with foot drop as the initial symptom arising from thoracic disc herniation were collected from January 2015 to December 2020. The average follow-up period was 20.5 months. We recorded neurological functions, the tibialis anterior muscle strength, Japanese Orthopedic Association score (JOA), location of the lesion, and occupation rate of herniation in the spinal canal preoperatively and at the final follow-up. RESULTS: None pathological reflex was found in the patients. Surgical treatment was performed in 12 of the 13 patients, and tibialis anterior functional recovery was observed in 83.4% (10/12) of the cases, with an average recovery rate of 52.8 ± 18.5%. The mean JOA score increased from 6.8 ± 1.9 points preoperatively to 8.9 ± 1.3 points postoperatively (p < 0.05), achieving a mean recovery rate of 52.3 ± 13.1%. The MRI showed the conus medullaris was obviously compressed at the level of T11-L1, and the occupation rate of herniation was more than 40% in all patients, with an average of 65.4 ± 16.3%. CT indicated that 84.6% of the cases had calcification in intervertebral discs. CONCLUSION: Foot drop can be the initial symptom caused by thoracic disc herniation at the T11-L1 level, especially for the calcified disc herniation. A satisfactory recovery rate can be achieved by surgical decompression with fixation.

Ganglion Cysts of the Proximal Tibiofibular Joint: Low Risk of Recurrence After Total Cyst Excision.

BACKGROUND: Peroneal nerve neuropathy due to compression from tumors or tumor-like lesions such as ganglion cysts is rare. Few case series have been published and reported local recurrence rates are high, while secondary procedures are frequently employed. QUESTIONS/PURPOSES: (1) What are the demographics of patients with ganglion cysts of the proximal tibiofibular joint, and what proportion of them present with intraneural cysts and peroneal nerve palsy? (2) What Musculoskeletal Tumor Society (MSTS) scores do patients with this condition achieve after decompression surgery with removal of the ganglion cyst, but no arthrodesis of the tibiofibular joint? (3) What proportion of patients experience local recurrence after surgery? METHODS: Between 2009 to 2018, 30 patients (29 primary cases) were treated for chronic peroneal palsy or neuropathy due to ganglion cysts of the proximal tibiofibular joint at two tertiary orthopaedic medical centers with total resection of the cystic lesion. MRI with contrast and electromyography (EMG) were performed preoperatively in all patients. The minimum follow-up for this series was 1 year (median 48 months, range 13 to 120); 14% (4 of 29) were lost to follow-up before that time. The MSTS score was recorded preoperatively, at 6 weeks postoperatively, and at most-recent follow-up. RESULTS: A total of 90% of the patients were male (26 of 29 patients) and the median age was 67 years (range 20 to 76). In all, 17% (5 of 29) were treated due to intraneural ganglia. Twenty-eight percent (8 of 29) presented with complete peroneal palsy (foot drop). The mean MSTS score improved from 67 ± 12% before surgery to 89 ± 12% at 6 weeks postoperative (p < 0.001) and to 92 ± 9% at final follow up (p = 0.003, comparison with 6 weeks postop). All patients improved their scores. A total of 8% (2 of 25 patients) experienced local recurrence after surgery. CONCLUSION: Ganglion cysts of the proximal tibiofibular joint occurred more often as extraneural lesions in older male patients in this small series. Total excision was associated with improved functional outcome and low risk of neurologic damage and local recurrence, and we did not use any more complex reconstructive procedures. Tendon transfers may be performed simultaneously in older patients to stabilize the ankle joint, while younger patients may recover after decompression alone, although larger randomized studies are needed to confirm our preliminary observations. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Acute bilateral foot drop with or without cauda equina syndrome-a case series.

INTRODUCTION: Isolated acute bilateral foot drop due to degenerative spine disease is an extremely rare neurosurgical presentation, whilst the literature is rich with accounts of chronic bilateral foot drop occurring as a sequela of systemic illnesses. We present, to our knowledge, the largest case series of acute bilateral foot drop, with trauma and relevant systemic illness excluded. METHODS: Data from three different centres had been collected at the time of historic treatment, and records were subsequently reviewed retrospectively, documenting the clinical presentation, radiological level of compression, timing of surgery, and degree of neurological recovery. RESULTS: Seven patients are presented. The mean age at presentation was 52.1 years (range 41-66). All patients but one were male. All had a painful radiculopathic presentation. Relevant discopathy was observed from L2/3 to L5/S1, the commonest level being L3/4. Five were treated within 24 h of presentation, and two within 48 h. Three had concomitant cauda equina syndrome; of these, the first two made a full motor recovery, one by 6 weeks follow-up and the second on the same-day post-op evaluation. Overall, five out of seven cases had full resolution of their ankle dorsiflexion pareses. One patient with 1/5 power has not improved. Another with 1/5 weakness improved to normal on the one side and to 3/5 on the other. CONCLUSION: When bilateral foot drop occurs acutely, we encourage the consideration of degenerative spinal disease. Relevant discopathy was observed from L2/3 to L5/S1; aberrant innervation may be at play. Cauda equina syndrome is not necessarily associated with acute bilateral foot drop. The prognosis seems to be pretty good with respect to recovery of the foot drop, especially if partial at presentation and if treated within 48 h.

Skin Lesions, Foot Drop, and Hand Contractures.

A previously healthy individual in his 20s had 3 months of annular skin lesions, with numbness and paresthesia in the affected areas. Physical examination revealed multiple tattoos, bilateral palpable thickened auricular and ulnar nerves, and claw-hand deformity; test results for rapid plasma reagin, antinuclear antibodies, rheumatoid factor, acid-fast bacilli, mycobacteria, and fungi were negative, and biopsy did not identify Mycobacterium leprae. What is the diagnosis and what would you do next?

Recognition of peroneal intraneural ganglia in an historical cohort with "negative" MRIs.

BACKGROUND: The objective of this study was to review an historical cohort of patients with peroneal neuropathy and magnetic resonance imaging (MRI) read as negative for mass or cyst to determine if occult peroneal intraneural ganglion cysts can be identified on subsequent imaging review and to use this as an estimation of how under-recognized this pathologic entity is. METHOD: The patient cohort utilized in this study was a previously published control cohort of 11 patients with peroneal neuropathy and MRI read as negative for mass or cyst. Clinical history, neurologic examination, and MRI studies of the knee were reviewed for each of the included patients. The primary outcome of interest was the presence of peroneal intraneural ganglion cyst on MRI. RESULTS: Overall, 7 of 11 (64%) patients in this historical "normal" cohort had evidence of a peroneal intraneural ganglion cyst on subsequent review of imaging. Deep peroneal-predominant weakness, knee pain, and tibialis anterior-predominant denervation/atrophy were seen more commonly in patients in whom an intraneural cyst was identified. CONCLUSIONS: This retrospective cohort study provides evidence that peroneal intraneural ganglion cysts are an historically under-recognized cause of peroneal neuropathy, with 64% of this historical "negative" cohort having evidence of a cyst on subsequent imaging review. Larger studies are needed to determine the treatment ramifications of identifying small cysts and to determine the clinical features suggestive of an intraneural ganglion cyst.

Motor neuropathies and lower motor neuron syndromes.

Motor or motor-predominant neuropathies may arise from disease processes affecting the motor axon and/or its surrounding myelin. Lower motor neuron syndrome (LMNS) arises from a disease process affecting the spinal motor neuron itself. The term LMNS is more generally used, rather than motor neuronopathy, although both entities are clinically similar. Common features are muscle weakness (distal or proximal) with atrophy and hyporeflexia, but no sensory involvement. They can be acquired or hereditary. Immune-mediated neuropathies (multifocal motor neuropathy, motor-predominant chronic inflammatory demyelinating polyneuropathy) are important to identify, as effective treatments are available. Other acquired neuropathies, such as infectious, paraneoplastic and radiation-induced neuropathies are also well known. Focal LMNS is an amyotrophic lateral sclerosis (ALS)-mimicking syndrome especially affecting young adults. The main hereditary LMNSs in adulthood are Kennedy's disease, late-onset spinal muscular atrophy and distal hereditary motor neuropathies. Motor neuropathies and LMNS are all clinical entities that should be better known, despite being rare diseases. They can sometimes be difficult to differentially diagnose from other diseases, particularly from the more frequent ALS in its pure LMN form. Nevertheless, correct identification of these syndromes is important because their treatment and prognoses are definitely different.

Correlation between muscle electrophysiology and strength after fibular nerve injury.

Muscle strength measurement is important when evaluating the degree of impairment in patients with nerve injury. However, accurate and objective evaluation may be difficult in patients with severe pain or those who intentionally try to avoid full exertion. We investigated the usefulness of the affected-to-unaffected side electrophysiological parameter ratios as a measure of objective ankle dorsiflexion (ADF) strength in patients with unilateral fibular nerve injury (FNI). ADF strength was measured in patients with FNI via handheld dynamometer and manual muscle test (MMT). Fibular nerve compound muscle action potential (CMAP) amplitude and latency and ADF strength of the affected side were presented as ratios to the corresponding measurements of the unaffected side. We analysed the correlation of the CMAP ratio with the ADF strength ratio using a dynamometer and compared the CMAP ratios according to MMT grade. Fifty-two patients with FNI were enrolled. The mean CMAP latency ratio did not differ between MMT groups (p = 0.573). The CMAP amplitude ratio proportionally increased with the quantified ADF strength ratio via dynamometer increase (ρ = 0.790; p < 0.001), but the CMAP latency ratio and the quantified ADF strength ratio did not significantly correlate (ρ = 0.052; p = 0.713). The average CMAP amplitude ratio significantly differed between MMT groups (p < 0.001), and post hoc tests showed significant differences in all paired comparisons except of Fair and Good grades (p = 0.064). Electrophysiological parameter ratio, such as the affected-to-unaffected side CMAP amplitude ratio, might be sensitive parameters for ADF power estimation after FNI.

Traumatic neuroma of the superficial peroneal nerve in a patient: a case report and review of the literature.

BACKGROUND: Traumatic neuromas are rare benign tumors, which are common in trauma or post-operation and accompanied with obvious symptoms of pain. This study will show the superficial peroneal nerve neuroma occurring after resection of hemangioma. CASE PRESENTATION: A 44-year-old male had an operation of the right leg cavernous hemangioma resection in 1995. Half a year after the operation, pain around the wound appeared and gradually aggravated. The patient had the lesion exploration resection in 2013, and the pathological result showed traumatic neuroma. Within half a year of the second operation, severe pain showed up again, so neuroma resection proceeded in May 2015. The postoperative pathological and immunohistochemical results showed traumatic neuroma. According to the postoperative follow-up, there were no symptoms of pain appearing again. LITERATURE REVIEW: The pain is obvious, and B ultrasonography is the most efficient way to find neuromas. Both conservative and operative therapy have their advantages and disadvantages. CONCLUSIONS: There remain many unanswered questions in relation to the treatment of traumatic neuromas, and further research is required, although we have already had adequate understanding of traumatic neuromas.

Postsynaptic potentiation of corticospinal projecting neurons in the anterior cingulate cortex after nerve injury.

Long-term potentiation (LTP) is the key cellular mechanism for physiological learning and pathological chronic pain. In the anterior cingulate cortex (ACC), postsynaptic recruitment or modification of AMPA receptor (AMPAR) GluA1 contribute to the expression of LTP. Here we report that pyramidal cells in the deep layers of the ACC send direct descending projecting terminals to the dorsal horn of the spinal cord (lamina I-III). After peripheral nerve injury, these projection cells are activated, and postsynaptic excitatory responses of these descending projecting neurons were significantly enhanced. Newly recruited AMPARs contribute to the potentiated synaptic transmission of cingulate neurons. PKA-dependent phosphorylation of GluA1 is important, since enhanced synaptic transmission was abolished in GluA1 phosphorylation site serine-845 mutant mice. Our findings provide strong evidence that peripheral nerve injury induce long-term enhancement of cortical-spinal projecting cells in the ACC. Direct top-down projection system provides rapid and profound modulation of spinal sensory transmission, including painful information. Inhibiting cortical top-down descending facilitation may serve as a novel target for treating neuropathic pain.

Successful delayed reconstruction of common peroneal neuroma-in-continuity using sural nerve graft.

Injuries of the common peroneal nerve (CPN) are frequent and associated with poor motor outcomes. So far, the opinion is held, that nerve reconstruction is reasonable and indicated up to 6 months after injury. We describe successful sural nerve interposition grafting in a patient with neuroma-in-continuity formation of the CPN, presenting with foot drop, 13 months after injury. Due to this positive result, we think nerve grafting in neuroma-in-continuity lesions of the CPN should be contemplated in patients with foot drop even more than one year after injury.

Influence of a fabella in the gastrocnemius muscle on the common fibular nerve in Japanese subjects.

The fabella is a sesamoid bone located in the proximal tendon of the gastrocnemius muscle. In rare cases, its presence may lead to a variety of clinical problems, including fabella syndrome and common fibular (CF) nerve palsy. The purpose of this study was to analyze the morphology of the fabella and CF nerve and discuss the influence of any existing fabellae on the size of the CF nerve. The morphology of the fabella and CF nerve in the popliteal region of the lateral head of the gastrocnemius muscle was investigated in 102 knees of 51 Japanese cadavers. The maximum circumference of the thigh, knee, and calf and the frequency, position, and size of the fabella were measured. In addition, the CF nerve width and thickness were measured proximal to the fabellar region and again as the CF nerve passed posterior, lateral, or medial to the region. A fabella was observed in 70 knees (68.6%). The CF nerve adjacent to the fabella was significantly wider and thinner than in the region proximal to the fabella (P < 0.001). In cases in which a bony fabella was present, there was a significant relationship between the thickness of the CF nerve and the circumference of the thigh and knee. The following factors were observed to contribute to the presence of a fabella causing alterations in the size of the CF nerve: a bony fabella, a CF nerve path posterior or lateral to the fabella, and subjects with a thin physique and bony fabella.

High-resolution 3-T MR neurography of peroneal neuropathy.

The common peroneal nerve (CPN), a major terminal branch of the sciatic nerve, can be subject to a variety of pathologies, which may affect the nerve at any level from the lumbar plexus to its distal branches. Although the diagnosis of peripheral neuropathy is traditionally based on a patient's clinical findings and electrodiagnostic tests, magnetic resonance neurography (MRN) is gaining an increasing role in the definition of the type, site, and extent of peripheral nerve disorders. Current high-field MR scanners enable high-resolution and excellent soft-tissue contrast imaging of peripheral nerves. In the lower extremities, MR neurography has been employed in the demonstration of the anatomy and pathology of the CPN, as well as in the detection of associated secondary muscle denervation changes. This article reviews the normal appearance of the CPN as well as typical pathologies and abnormal findings at 3.0-T MR neurography of the lower extremity.

Ischaemic monomelic neuropathy: A rare cause of unilateral foot drop.

Ischaemic neuropathy is a rare phenomenon given the rich arterial collateral supply afforded to peripheral nerves by the vasa nervorum. We report an unusual case of unilateral foot drop secondary to long-segment popliteal artery occlusion. Without expedient vessel imaging and revascularisation of the occluded artery, this reversible cause of neurological deficit would likely have resulted in a poor functional outcome for our patient.

Behavioural and anatomical analysis of selective tibial nerve branch transfer to the deep peroneal nerve in the rat.

Nerve transfer procedures involving the repair of a distal denervated nerve element with that of a foreign proximal nerve have become increasingly popular for clinical nerve repair as a surgical alternative to autologous nerve grafting. However, the functional outcomes and the central plasticity for these procedures remain poorly defined, particularly for a clinically relevant rodent model of hindlimb nerve transfer. We therefore evaluated the effect of selective tibial branch nerve transfer on behavioural recovery in animals following acute transection of the deep peroneal nerve. The results indicate that not only can hindlimb nerve transfers be successfully accomplished in a rat model but that these animals display a return of skilled locomotor function on a par with animals that underwent direct deep peroneal nerve repair (the current gold standard). At 2 months, ground reaction force analysis demonstrated that partial restoration of braking forces occurred in the nerve transfer group, whereas the direct repair group had fully restored these forces to similar to baseline levels. Ankle kinematic analysis revealed that only animals in the direct repair group significantly recovered flexion during the step cycle, indicating a recovery of surgically induced foot drop. Terminal electrophysiological and myological assessments demonstrated similar levels of reinnervation, whereas retrograde labelling studies confirmed that the peroneal nerve-innervated muscles were innervated by neurons from the tibial nerve pool in the nerve transfer group. Our results demonstrate a task-dependent recovery process, where skilled locomotor recovery is similar between nerve transfer and direct repair animals, whereas flat surface locomotion is significantly better in direct repair animals.

Compression peroneal neuropathy following a bicycle injury in a child.

BACKGROUND: The spectrum of bicycle riding injuries is extremely wide. However, compression peroneal neuropathy complicating a bicycle injury has not been previously reported. CASE REPORT: An 11-year-old girl with common peroneal neuropathy is presented. Her knee was caught in between the chain stay and the crank arm on the left side of her bicycle and was jammed. Clinical examination indicated a motor paralysis producing foot drop and a sensory deficit over the lateral calf and the dorsum of the foot. Magnetic resonance imaging (MRI), although not diagnostic, provided useful information regarding soft tissue injury in relation to the common peroneal nerve's course in the popliteal fossa. An electrodiagnostic (EDX) study was indicative of a common peroneal neuropathy. Complete recovery of the peroneal nerve was noted 7 months post-injury. CONCLUSIONS: Compression peroneal neuropathy may be included in traumatic bicycle-related injuries, while the space between the chain stay and the crank arm on the left side of the bicycle may be recognized as potentially hazardous to entrap the rider's leg.

Entrapment neuropathies III: lower limb.

Clinicians frequently encounter compressive neuropathies of the lower extremity. The clinical history and physical examination, along with electrodiagnostic testing and imaging studies, lead to the correct diagnosis. The imaging characteristics of the compression neuropathies can include acute and chronic changes in the nerves and the muscles they innervate. We provide a detailed review of compression neuropathies of the lower extremity with an emphasis on magnetic resonance (MR) imaging characteristics. We discuss the clinical presentation, etiology, anatomical location, and MR imaging appearance of these neuropathies, including the piriformis syndrome, iliacus syndrome, saphenous neuropathy, obturator neuropathy, lateral femoral cutaneous neuropathy (meralgia paresthetica), proximal tibial neuropathy, common peroneal neuropathy, deep peroneal neuropathy, superficial peroneal neuropathy, tarsal tunnel syndrome, Baxter's neuropathy, jogger's foot, sural neuropathy, and Morton's neuroma.

Synovial cyst that compressed the peroneal nerve: case report.

We report a case of synovial cyst that induced the compression of the peroneal nerve. The patient presented with foot drop and impossibility to stand on his right heel associated with numbness of anterolateral surfaces of the right shin and the dorsal surface of the foot within a 1-month period. Based on the clinical examination and electroneuromyography data, the compression of nerve by soft elastic mass was confirmed. We treated the patient by total microsurgical excision of the soft elastic mass adherent to the right peroneal nerve at the top third of the patient's shin. Histological study revealed the cyst of synovial membrane. During the postoperative period, a force in extensors of the right foot was restored. On the seventh day, the patient began to step on his right heel, while the zone of tenderness and temperature hypoesthesia in the area of the peroneal nerve innervation remained.

A Cadaveric Study of the Distal Biceps Femoris Muscle in relation to the Normal and Variant Course of the Common Peroneal Nerve: A Possible Cause of Common Peroneal Entrapment Neuropathy.

The most frequent mononeuropathy in the lower extremity has been reported as the common peroneal nerve entrapment neuropathy (CPNe) around the head and neck of the fibula, although the mechanism of the neuropathy in this area cannot be fully explained. Therefore, the aim of this cadaveric study was to evaluate the relationship between morphologic variations of the distal biceps femoris muscle (BFM) and the course of the common peroneal nerve (CPN) and to investigate the incidence and morphological characteristics of anatomical variations in the BFM associated with CPNe. The popliteal region and the thigh were dissected in 115 formalin-fixed lower limbs. We evaluated consensus for (1) normal anatomy of the distal BFM, (2) anatomic variations of this muscle, and (3) the relationship of the muscle to the CPN. Measurements of the distal extents of the short and long heads of the BFM from insertion (fibular head) were performed. Two anatomic patterns were seen. First, in 93 knees (80.8%), the CPN ran obliquely along the lateral side of the BFM and then superficial to the lateral head of the gastrocnemius muscle. Second, in 22 cases (19.2%), the CPN coursed within a tunnel between the biceps femoris and lateral head of the gastrocnemius muscle (LGCM). There was a positive correlation between the distal extents of the short heads of the biceps femoris muscle (SHBFM) and the presence of the tunnel. The "popliteal intermuscular tunnel" in which the CPN travels can be produced between the more distal extension variant of the SHBFM and the LGCM. This anatomical variation of BFM may have a clinical significance as an entrapment area of the CPN in the patients in which the mechanism of CPNe around the fibula head and neck is not understood.

Diagnostic and management considerations in incidental common peroneal intraneural haemangioma.

Intraneural haemangiomas are rare tumours that can affect peripheral nerves. We describe a case of a 10-year-old female with an incidental finding of a common peroneal nerve lesion following knee injury. MRI demonstrated avid heterogeneous enhancement and peri-lesional oedema, and an open biopsy was performed revealing haemangioma on histopathological analysis. The patient was managed with observation and remains intact at 24-month follow-up.