Piriformis syndrome.

Piriformis syndrome is a condition that is proposed to result from compression of the sciatic nerve, either in whole or in part, in the deep gluteal space by the piriformis muscle. The prevalence of piriformis syndrome depends upon the diagnostic criteria being used and the population studied but is estimated by some to be 5%-6% in all cases of low back, buttock, and leg pain and up to 17% of patients with chronic low back pain. While the sciatic nerve may pierce the piriformis muscle in about 16% of healthy individuals, this frequency is no different in those with the syndrome; thus, the relationship to this anatomic finding is unclear. The most common symptoms are buttock pain, external tenderness over the greater sciatic notch, and aggravation of the pain through sitting. Many clinical signs are reported for piriformis syndrome, but the sensitivity and specificity are unclear, in part because of the lack of a uniformly accepted case definition. In the majority of cases in the literature, it appears that the diagnosis is more ascribed to a myofascial condition rather than a focal neuropathy. Electrodiagnostic studies can be useful to exclude other causes of symptoms, but there is no well-accepted test to confirm the presence of piriformis syndrome. Ultrasound imaging may show thickening of the piriformis muscle, but further research is required to confirm that this is correlated with the clinical diagnosis. Magnetic resonance imaging and neurography may hold promise in the future, but there are not yet sufficient data to support adopting these methods as a standard diagnostic tool. The initial treatment of piriformis syndrome is typically conservative management with the general rehabilitation principles similar to other soft tissue musculoskeletal conditions. Local anesthetic, botulinum toxin, and/or corticosteroid injections have been reported by some to be beneficial for diagnostic or treatment purposes. Surgical interventions have also been used with variable success.

Postpolio syndrome and the late effects of poliomyelitis. Part 1. pathogenesis, biomechanical considerations, diagnosis, and investigations.

Postpolio syndrome (PPS) is characterized by new muscle weakness and/or muscle fatigability that occurs many years after the initial poliomyelitis illness. Many theories exist regarding the pathogenesis of PPS, which remains incompletely understood. In contrast, the late effects of poliomyelitis are often a consequence of biomechanical alterations that occur as a result of polio-related surgeries, musculoskeletal deformities, or weakness. Osteoporosis and fractures of the polio-involved limbs are common. A comprehensive clinical evaluation with appropriate investigations is essential to fulfilling the established PPS diagnostic criteria. PPS is a diagnosis of exclusion in which a key clinical feature required for the diagnosis is new muscle weakness and/or muscle fatigability that is persistent for at least 1 year. Electromyographic and muscle biopsy findings including evidence of ongoing denervation cannot reliably distinguish between patients with or without PPS. Muscle Nerve 58:751-759, 2018.

Post-polio syndrome and the late effects of poliomyelitis: Part 2. treatment, management, and prognosis.

Post-polio syndrome (PPS) is characterized by new muscle weakness and/or muscle fatigability that occurs many years after the initial poliomyelitis illness. An individualized approach to rehabilitation management is critical. Interventions may include rehabilitation management strategies, adaptive equipment, orthotic equipment, gait/mobility aids, and a variety of therapeutic exercises. The progression of muscle weakness in PPS is typically slow and gradual; however, there is also variability in both the natural history of weakness and functional prognosis. Further research is required to determine the effectiveness of selected medical treatment. Muscle Nerve 58:760-769, 2018.

Prospective evaluation of the clinical prediction of electrodiagnostic results in carpal tunnel syndrome.

OBJECTIVE: To develop a unique clinical prediction point-score system for the diagnosis of carpal tunnel syndrome (CTS) and to prospectively evaluate this clinical rule to determine its ability to predict electrodiagnostic results. DESIGN: Retrospective case control to develop the clinical point-score system and then prospective diagnostic study with blind comparison to electrodiagnostic results. SETTING: Community-based electrodiagnostic laboratory. PATIENTS: A total of 348 subjects referred to the electrodiagnostic laboratory with a clinical suspicion of CTS to develop the clinical point-score system and then a different population of 278 subjects referred to the electrodiagnostic laboratory over a 1-year period with a clinical suspicion of CTS to prospectively evaluate the ability of the clinical rule to predict electrodiagnostic results. MAIN OUTCOME MEASURES: Clinical point-score system results were compared with the electrodiagnostic results for CTS, which served as the primary outcome measure. RESULTS: A "weighted" point-score system was developed from 9 clinical variables including: gender, duration of symptoms, presence of wrist pain (negative predictor), presence of neck pain (negative predictor), nocturnal symptoms, presence of thenar atrophy, abductor pollicis brevis weakness, median sensory symptoms, and results of pinprick sensation examination. The prospective evaluation indicated that the clinical point-score rule, overall, performed moderately in predicting electrodiagnostic results (receiver operator characteristic curve = 0.80). The clinical point score was most predictive in a small subset of subjects with very high scores. However, in most subjects, the clinical point score could not accurately predict electrodiagnostic outcome in CTS, particularly in subjects with middle to low clinical point scores. CONCLUSIONS: The developed clinical point-score rule was most predictive in subjects with high point score; however, the majority of the referrals to the electrodiagnostic laboratory indicated that the electrodiagnostic studies provided additional, independent information beyond what could be obtained by the clinical point score.

Community-based referrals for electrodiagnostic studies in patients with possible carpal tunnel syndrome: what is the diagnosis?

OBJECTIVES: To determine what proportion of patients referred with a clinical suspicion of carpal tunnel syndrome (CTS) have negative electrodiagnostic studies and identify their clinical diagnoses and to identify clinical features that predict the outcome of electrodiagnostic testing in patients referred with suspected CTS. DESIGN: Retrospective review of patients consecutively referred to the electrodiagnostic center with suspected CTS over a 1-year period. SETTING: Community-based electrodiagnostic center. PARTICIPANTS: Three hundred forty-eight patients with suspected CTS. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: The diagnosis of CTS was based on the electrodiagnostic findings. RESULTS: Of the 348 patients enrolled, 179 (51.4%) had electrodiagnostic studies that were inconsistent with a diagnosis of CTS. Twenty-seven patients (15.1%) had other electrodiagnostic abnormalities (eg, ulnar neuropathy, cervical radiculopathy), whereas the remaining 152 (84.9%) patients had studies within normal limits. Seventy-one patients (46.7%) with normal studies were diagnosed with musculoskeletal disorders, with myofascial pain and musculotendinous strain being most common. By using a multiple logistic regression model, clinical variables that may predict the outcome of electrodiagnostic testing for CTS included gender, duration of symptoms, nocturnal symptoms, sensory symptoms, wrist pain, neck pain, pinprick sensation, abductor pollicis brevis strength, and thenar bulk. CONCLUSIONS: Many patients referred to an electrodiagnostic laboratory with a clinical suspicion of CTS have other diagnoses, most commonly musculoskeletal disorders. Because these various conditions may be mistaken for CTS, the electrodiagnostic evaluation is therefore an important diagnostic tool. Although traditional clinical findings including Tinel and Phalen sign were found to have limited clinical use, further validation of the groups of positive and negative clinical features may potentially enable the referring physician to identify more accurately patients who would benefit most from electrodiagnostic testing.