Pediatric sciatic neuropathy: Clinical presentation and long term follow up. / Neuropatía ciática en pediatría: Presentación clínica y seguimiento a largo plazo.

INTRODUCTION: Sciatic neuropathy is rare and difficult to diagnose in pediatrics, and its long-term course has not been completely understood. OBJECTIVE: To analyze the clinical presentation and evolution of a group of pediatric patients with sciatic neuropathy. PATIENTS AND METHOD: Retrospective anal ysis of the clinical characteristics of pediatric patients with sciatic neuropathy treated in two hospitals of Santiago between 2014 and 2018. Locomotor examination, muscle trophism, deep tendon reflexes, gait, sensation, and pain were assessed. Sciatic nerve conduction study and electromyography (EMG) were performed, and magnetic resonance imaging (MRI) in three patients. RESULTS: Six patients were included with an average age of 11.8 years. The etiologies were traumatic (N = 2), by compression (N = 2), vascular (N = 1), and tumor (N = 1). All of the 6 patients presented foot drop and Achilles tendon hyporeflexia/areflexia, and 5 patients presented severe neuropathic pain. The EMG showed involvement of the sciatic nerve rami and dependent muscles. In two patients, a pelvic girdle and lower limbs MRI was performed, showing selective muscle involvement in sciatic territory. One patient underwent a lumbosacral plexus MRI, and subsequently histological study showing a benign neural tumor. Out of the three patients who were followed-up longer than one year presented motor sequelae and gait disorder. CONCLUSION: Sciatic neuropathy in the study group was secondary to different causes, predominantly traumatic and compressive etiologies. The three patients that were ina long-term follow-up presented significant motor sequelae. In most of the cases, neural injury wasassoci- ated with preventable causes, such as accidents and positioning in unconscious children, which is crucial in the prevention of a pathology with a high sequelae degree.

Visualizing neuroinflammation with fluorescence and luminescent lanthanide-based in situ hybridization.

BACKGROUND: Neurokine signaling via the release of neurally active cytokines arises from glial reactivity and is mechanistically implicated in central nervous system (CNS) pathologies such as chronic pain, trauma, neurodegenerative diseases, and complex psychiatric illnesses. Despite significant advancements in the methodologies used to conjugate, incorporate, and visualize fluorescent molecules, imaging of rare yet high potency events within the CNS is restricted by the low signal to noise ratio experienced within the CNS. The brain and spinal cord have high cellular autofluorescence, making the imaging of critical neurokine signaling and permissive transcriptional cellular events unreliable and difficult in many cases. METHODS: In this manuscript, we developed a method for background-free imaging of the transcriptional events that precede neurokine signaling using targeted mRNA transcripts labeled with luminescent lanthanide chelates and imaged via time-gated microscopy. To provide examples of the usefulness this method can offer to the field, the mRNA expression of toll-like receptor 4 (TLR4) was visualized with traditional fluorescent in situ hybridization (FISH) or luminescent lanthanide chelate-based in situ hybridization (LISH) in mouse BV2 microglia or J774 macrophage phenotype cells following lipopolysaccharide stimulation. TLR4 mRNA staining using LISH- and FISH-based methods was also visualized in fixed spinal cord tissues from BALB/c mice with a chronic constriction model of neuropathic pain or a surgical sham model in order to demonstrate the application of this new methodology in CNS tissue samples. RESULTS: Significant increases in TLR4 mRNA expression and autofluorescence were visualized over time in mouse BV2 microglia or mouse J774 macrophage phenotype cells following lipopolysaccharide (LPS) stimulation. When imaged in a background-free environment with LISH-based detection and time-gated microscopy, increased TLR4 mRNA was observed in BV2 microglia cells 4 h following LPS stimulation, which returned to near baseline levels by 24 h. Background-free imaging of mouse spinal cord tissues with LISH-based detection and time-gated microscopy demonstrated a high degree of regional TLR4 mRNA expression in BALB/c mice with a chronic constriction model of neuropathic pain compared to the surgical sham model. CONCLUSIONS: Advantages offered by adopting this novel methodology for visualizing neurokine signaling with time-gated microscopy compared to traditional fluorescent microscopy are provided.

Clinical and Electrodiagnostic Features Of Nontraumatic Sciatic Neuropathy.

INTRODUCTION: In this study we sought to characterize etiologies and features of sciatic neuropathy unrelated to penetrating nerve trauma. METHODS: This investigation was a retrospective review of 109 patients with electrodiagnostically confirmed sciatic neuropathies. RESULTS: Hip replacement surgery represented the most common (34.9%) etiology, whereas inflammatory sciatic neuropathy was seen in 7.3%. Electrodiagnostic testing revealed an axonal neuropathy in 95.4% and a demyelinating neuropathy in 4.6%. Predominant involvement of the peroneal division was seen in 39.4% and was tibial in 5.5%. Nine of 31 (29.0%) patients who had MRI or neuromuscular ultrasound study showed abnormalities within the sciatic nerve. At the final visit, 46.4% of patients required assistance for ambulation. Young age, lack of severe initial weakness, and presence of tibial compound muscle action potential or sural sensory nerve action potential were predictors of favorable outcome. DISCUSSION: Sciatic neuropathies are usually axonal on electrodiagnostic testing, affect preferentially the peroneal division, and are commonly associated with incomplete recovery. Muscle Nerve 59:309-314, 2019.

Delayed sciatic nerve compression following hamstring injury.

A 47-year-old man presented three months post-hamstring injury with posterior thigh and buttock pain, paraesthesia over the lateral part of the leg and dorsum of the foot and a foot drop. MRI identified a hamstring muscle injury with a lesion surrounding 20 cm of the proximal sciatic nerve consistent with an extensive haematoma. Surgical debridement and release was planned; however, his signs spontaneously resolved with rest, physiotherapy and splintage prior to surgery. There have been no other reports of a sciatic nerve lesion with neurological signs resolving without surgical exploration.

Sciatic neuropathy due to popliteal fossa nerve block.

INTRODUCTION: Sciatic neuropathy after popliteal nerve block (PNB) for regional anesthesia is considered uncommon but has been increasingly recognized in the literature. We identified a case of sciatic neuropathy that occurred after bunionectomy during which a PNB had been performed. METHODS: To understand the frequency of PNB-related sciatic neuropathy, we performed a retrospective review of sciatic neuropathies at our center over a 5-year period. RESULTS: Forty-five cases of sciatic neuropathy were reviewed. Similar to earlier reports, common etiologies of sciatic neuropathy, including compression, trauma, fractures, and hip arthroplasty, were noted in the majority of our cases (60%, n = 27). Unexpectedly, PNB was the third most common etiology (16%, n = 7). CONCLUSIONS: Our results suggest PNB is a relatively common etiology of sciatic neuropathy and is an important consideration in the differential diagnosis. These findings should urge electromyographers to assess history of PNB in sciatic neuropathies, particularly with onset after surgery. Muscle Nerve 56: 822-824, 2017.

Multimodal nerve monitoring during periacetabular osteotomy identifies surgical steps associated with risk of injury.

PURPOSE: Sciatic nerve palsy after periacetabular osteotomy (PAO) is a serious complication. The purpose of this study was to determine whether a multimodal sciatic monitoring technique allows for identification of surgical steps that place the sciatic nerve at risk. METHODS: Transcranial electrical motor evoked potentials (TcMEPs), somatosensory evoked potentials (SSEPs), and spontaneous electromyography (EMG) were monitored in a consecutive series of 34 patients (40 hips) who underwent PAO for the treatment of symptomatic hip dysplasia between January 2012 and November 2014. There were 29 females (85%) and five males (15%) with an average age of 19 years (range, 12-36 years) at the time of surgery. RESULTS: We detected eight temporary sciatic nerve monitoring alerts in six patients (incidence of 15%). The events included decrease in amplitude of the TcMEPs related to the position of the hip during incomplete ischium osteotomy and placement of a retractor in the sciatic notch during the posterior column osteotomy (N = 3), generalized bilateral decrease in TcMEPs during fragment manipulation and fixation in association with acute blood loss (N = 2), and a change in SSEPs during a superior pubic osteotomy and supra-acetabular osteotomy (N = 1). At the end of the procedure, TcMEPs and SSEPs were at baseline and there was no abnormal pattern on EMG in all patients. Post-operatively, at two, six, 12 weeks, and six and 12 months, no motor weakness or sensory deficits were noted. CONCLUSION: Multimodal neuromonitoring allowed for identification of intra-operative steps and maneuvers that potentially place the sciatic nerve at higher risk of injury.

A case of infected schwannoma mimicking malignant tumor.

BACKGROUND: Infected schwannoma has been reported, this being one of the four cases published in the literature. Infected schwannoma has proven to be a tough diagnostic challenge to the treating tumor surgeon, mimicking infectious entities and most essentially, a malignant tumor. CASE PRESENTATION: The authors report the case of a 64-year-old male with a soft tissue mass in his right gluteal area that presented initially with right leg pain, then later with signs of inflammation on the tumor area. Magnetic resonance imaging (MRI), computed tomography (CT), and thallium-201 scintigraphy studies confirm the presence of soft tissue mass which had continuity with sciatic nerve, with subsequent serial MRI findings suggesting tumor enlargement with cystic degeneration. Increased level of C-reactive protein (CRP) was observed before surgery. During an open biopsy upon tissue sampling, exudates with necrotic tissue were seen. Increased level of CRP and necrotic change suggested the possibility of malignant tumor. Histopathological diagnosis was schwannoma, and group B Streptococcus was detected by culture. After the confirmation of infected schwannoma, enucleation of the tumor was performed. CONCLUSIONS: The report concludes that establishment of a benign pathology is essential when presented with similar clinical findings prior to definitive enucleation of an infected schwannoma.

4.7-T diffusion tensor imaging of acute traumatic peripheral nerve injury.

Diagnosis and management of peripheral nerve injury is complicated by the inability to assess microstructural features of injured nerve fibers via clinical examination and electrophysiology. Diffusion tensor imaging (DTI) has been shown to accurately detect nerve injury and regeneration in crush models of peripheral nerve injury, but no prior studies have been conducted on nerve transection, a surgical emergency that can lead to permanent weakness or paralysis. Acute sciatic nerve injuries were performed microsurgically to produce multiple grades of nerve transection in rats that were harvested 1 hour after surgery. High-resolution diffusion tensor images from ex vivo sciatic nerves were obtained using diffusion-weighted spin-echo acquisitions at 4.7 T. Fractional anisotropy was significantly reduced at the injury sites of transected rats compared with sham rats. Additionally, minor eigenvalues and radial diffusivity were profoundly elevated at all injury sites and were negatively correlated to the degree of injury. Diffusion tensor tractography showed discontinuities at all injury sites and significantly reduced continuous tract counts. These findings demonstrate that high-resolution DTI is a promising tool for acute diagnosis and grading of traumatic peripheral nerve injuries.

Sciatic nerve compression by neurogenic heterotopic ossification: use of CT to determine surgical indications.

OBJECTIVE: To describe the characteristics of neurogenic heterotopic ossification (NHO) based on clinical tests, electroneuromyography (ENMG) and CT in a database of patients with lesions of the central nervous system who required sciatic nerve neurolysis along with posterior hip NHO resection, and to determine the respective roles of ENMG and CT in the management of posterior hip NHOs in patients who are unable to communicate or express pain. METHODS: The consistency of the ENMG results with clinical findings, CT results and macroscopic signs of lesions was retrospectively assessed after sciatic nerve neurolysis and ablation of 55 posterior hip NHOs. RESULTS: Sciatic nerve neurolysis was necessary in 55 cases (47.4%; 55 out of 116). CT showed contact of the NHO with the nerve in all cases: 5 in contact with no deflection, 3 in contact with deflection, 21 moulded into a gutter and 26 entrapped in the NHO. There were clinical signs of sciatic nerve lesion in 21.8% of cases (12 out of 55). ENMG showed signs of sciatic nerve lesions in only 55.6% (10 out of 18), only 4 of whom presented with clinical signs of a nerve lesion. No significant relationship was found between clinical symptoms and ENMG findings of sciatic nerve compression (n = 13, p = 0.77). CONCLUSION: Nerve compression by NHO is likely an underdiagnosed condition, particularly in patients who are unable to communicate. Diagnosis of sciatic compression by NHO should be based on regular clinical examinations and CT. ENMG is not sufficiently sensitive to be used alone for surgical decision-making.

Post-injection sciatic neuropathy in a cynomolgus macaque (Macaca fascicularis).

BACKGROUND: Intramuscular injection is a common route parenteral used in primates. METHODS: A cynomolgus macaque was evaluated for acute lameness and atrophy of the left leg with no evidence of trauma. RESULTS: History revealed ketamine injection 12 days prior. CONCLUSIONS: Histologic examination supported traumatic injection neuropathy due to intramuscular injection.

Novel use of perineural pregabalin infusion for analgesia in a rat neuropathic pain model.

BACKGROUND: The anticonvulsant drugs pregabalin and gabapentin are often used systemically to treat some forms of chronic neuropathic pain. However, many patients report side effects serious enough to cause discontinuation of the drug. Here we present evidence that pregabalin may block neuropathic pain when applied to the site of nerve injury in a rat neuropathic pain model. METHODS: Forty male Sprague Dawley rats were randomized into 4 groups: sciatic nerve crush injury with perineural pregabalin treatment (treatment), crush injury with perineural saline treatment (saline control), crush injury with subcutaneous pregabalin treatment (systemic drug control), and sham surgery (sham surgery control). Animals received either continuous infusions of 1% pregabalin for 7 days (treatment and systemic control) or saline (saline control) and were tested for pain behaviors using incapacitance meter, guarding scores, and radiant heat withdrawal latency (Hargreaves method). Nerves were studied using histology and immunohistochemistry for α(2)δ-1 receptors thought to mediate the central analgesic action of pregabalin. RESULTS: Treatment rats had significantly better guarding scores than systemic drug controls or saline controls (P < 0.0001) and had significantly better incapacitance scores than systemic drug controls and saline controls (P ≤ 0.001). Hargreaves method data showed hypoalgesia in all injured animals with no difference among injured groups (P = 0.80). Qualitatively, immunohistochemistry likely showed equivalent expression of the α(2)δ-1 calcium channel at the injured nerve site in all nerve-injured animals. CONCLUSIONS: Perineural pregabalin administration produced superior analgesia compared with that of systemic pregabalin in this neuropathic pain model. Perineural pregabalin treatment may provide a useful alternative to systemic pregabalin treatment for neuropathic pain.

Neuromuscular choristoma of the sciatic nerve and lumbosacral plexus: an association with nerve-territory undergrowth in the pelvis affecting soft tissue and bone.

BACKGROUND: Neuromuscular choristomas (NMC) are rare congenital lesions with differentiated muscle found within peripheral nerves. Patients often present with progressive neuropathy, undergrowth of the affected limb, and limb length discrepancy. In the sciatic nerve (the most common location of NMC), this may lead to specific manifestations in the distal limb, including progressive neuropathy, a shortened atrophic limb and a cavus foot. We hypothesized that the presence of NMC of the sciatic nerve (proximal to the sciatic notch) extending to the lumbosacral plexus could lead to abnormalities in proximal nerve territories (i.e., nerve, muscle and bone) within the hemipelvis. METHODS: A retrospective review of all cases of sciatic nerve NMCs diagnosed at the Mayo Clinic was performed. RESULTS: Seven patients were identified with sciatic nerve NMCs extending proximal and distal to the sciatic notch. Four patients with NMCs had denervation of muscles within the pelvis and ipsilateral undergrowth of bone which resulted in three cases of hip dysplasia. To our knowledge, the finding of proximal nerve-territory soft tissue and bony undergrowth (including hip dysplasia) in patients with NMCs involving the sciatic nerve and lumbosacral plexus has not previously been recognized. CONCLUSION: This finding will aid in both the diagnosis of the disease and an understanding of associated conditions.

Symptoms of nerve dysfunction after hip arthroscopy: an under-reported complication?

PURPOSE: The primary purpose of this study was to analyze the rate, pattern, and severity of symptoms of nerve dysfunction after hip arthroscopy (HA) by reviewing prospectively collected data. The secondary purpose was to study whether symptoms of nerve dysfunction were related to traction time. METHODS: From March to October 2010, 52 consecutive patients-27 male patients (mean age, 40 years; range, 21 to 63 years) and 25 female patients (mean age, 37 years; range, 15 to 60 years), underwent HA with labral repair, rim trimming, and osteoplasty. The patients received a follow-up questionnaire 1 year after HA concerning symptoms of nerve dysfunction, possible localization, and erectile dysfunction. Fifty patients participated and returned fully completed questionnaires. Patients reporting symptoms of nerve dysfunction 1 year after HA were re-examined. RESULTS: Twenty-three of 50 patients (46%) reported symptoms of nerve dysfunction during the first week after HA; this was reduced to 14 patients (28%) after 6 weeks, 11 patients (22%) after 26 weeks, and 9 patients (18%) after 1 year. One patient experienced temporary erectile dysfunction. No difference in traction time between patients with symptoms of nerve dysfunction (n = 23) and patients without (n = 27) was found (98 minutes v 100 minutes; P = .88). CONCLUSIONS: Forty-six percent of patients undergoing HA reported symptoms of nerve dysfunction within the first 6 weeks after surgery. One year postoperatively, these symptoms remained in only 18% of all patients. Traction time during surgery was not different in patients with and those without symptoms of nerve dysfunction. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Long-term prognosis of nerve palsy after total hip arthroplasty: results of two-year-follow-ups and long-term results after a mean time of 8 years.

INTRODUCTION: Nerve damage is a rare but serious complication after THA. There exist only little data about the outcome of these patients particularly regarding the long-term results later than 2 years postoperatively. Aim of this study is to answer the following questions: Is the recovery to be expected for light nerve lesions different from the severe ones? Is there a possibility of nerve recovery more than 2 years after THA? Is the potential of nerve recovery depending on the affected nerve? MATERIALS AND METHODS: This study investigates 2,255 primary THA as well as revision surgeries performed from 1988 to 2003 relating to iatrogenic nerve lesion. We classified the nerve lesion according to the core muscle strength in severe (M0-M2) and light (M3-M4) nerve damage and differentiated between femoral, sciatic and superior gluteal nerve, according to the electromyography. RESULTS: We found 34 cases of iatrogenic nerve damage representing an incidence of 1.5 %. 17 of 34 (50 %) patients showed a complete recovery after 2 years. Out of the remaining 17 patients, six out of seven patients with a final examination after a median time of 93 months achieved further improvement. The different nerves showed no significant different potential of recovery. CONCLUSIONS: In contrast to the literature, an improvement beyond the limit of 2 years is probable and independent of the nerve affected.

Sciatic and tibial neuropathies.

The sciatic nerve is the body's largest peripheral nerve. Along with their two terminal divisions (tibial and fibular), their anatomic location makes them particularly vulnerable to trauma and iatrogenic injuries. A thorough understanding of the functional anatomy is required to adequately localize lesions in this lengthy neural pathway. Proximal disorders of the nerve can be challenging to precisely localize among a range of possibilities including lumbosacral pathology, radiculopathy, or piriformis syndrome. A correct diagnosis is based upon a thorough history and physical examination, which will then appropriately direct adjunctive investigations such as imaging and electrodiagnostic testing. Disorders of the sciatic nerve and its terminal branches are disabling for patients, and expert assessment by rehabilitation professionals is important in limiting their impact. Applying techniques established in the upper extremity, surgical reconstruction of lower extremity nerve dysfunction is rapidly improving and evolving. These new techniques, such as nerve transfers, require electrodiagnostic assessment of both the injured nerve(s) as well as healthy, potential donor nerves as part of a complete neurophysiological examination.

Traumatic and iatrogenic sciatic nerve injury in 38 dogs and 10 cats: Clinical and electrodiagnostic findings.

BACKGROUND: Reports describing sciatic nerve injuries (SNI) and their outcome are scarce in veterinary medicine. HYPOTHESIS: Describe the causes of traumatic and iatrogenic SNI and evaluate which clinical and electrodiagnostic findings predict outcome. ANIMALS: Thirty-eight dogs and 10 cats with confirmed SNI referred for neurologic and electrodiagnostic evaluation. METHODS: Clinical and electrodiagnostic examination results, including electromyography (EMG), motor nerve conduction studies, muscle-evoked potential (MEP), F-waves, sensory nerve conduction studies, and cord dorsum potential (CDP), were retrospectively evaluated. Quality of life (QoL) was assessed based on owner interviews. RESULTS: Surgery (42%) and trauma (33%) were the most common causes of SNI; in dogs, 24% were caused by bites from wild boars. Ability to flex and extend the tarsus was significantly associated with positive outcome in dogs. Mean time from onset of clinical signs until electrodiagnostic evaluation was 67 ± 65 (range, 7-300) days and 65 ± 108 (range, 7-365) days for dogs and cats, respectively. A cut-off amplitude of 1.45 mV for compound motor action potentials (CMAP) was predictive of positive outcome in dogs (P = .01), with sensitivity of 58% and specificity of 100%. CONCLUSIONS AND CLINICAL IMPORTANCE: Clinical motor function predicts recovery better than sensory function. Electrodiagnostic findings also may play a role in predicting the outcome of SNI. Application of the proposed CMAP cut-off amplitude may assist clinicians in shortening the time to reassessment or for earlier suggestion of salvage procedures. Owners perceived a good quality of life (QoL), even in cases of hindlimb amputation.

Lipomatosis of the sciatic nerve secondary to compression by a desmoid tumor.

Lipomatosis of nerve is a rare benign tumor-like process characterized by infiltration of the epineurium by adipose and fibrous tissue leading to nerve enlargement. We describe a case of lipomatosis of the sciatic nerve compressed by an adjacent desmoid tumor. This case supports the hypothesis that lipomatosis of nerve may form as a result of irritation or compression by adjacent structures.