Sonographic measures and sensory threshold of the normal sciatic nerve and hamstring muscles.

PURPOSE: The sciatic nerve innervates the hamstring muscles. Occasionally, the sciatic nerve is injured along with a hamstring muscle. Detailed biomechanical and sensory thresholds of these structures are not well-characterized. Therefore, we designed a prospective study that explored high-resolution ultrasound (US) at multiple sites to evaluate properties of the sciatic nerve, including cross-sectional area (CSA) and shear-wave elastography (SWE). We also assessed SWE of each hamstring muscle at multiple sites. Mechanical algometry was obtained from the sciatic nerve and hamstring muscles to assess multi-site pressure pain threshold (PPT). METHODS: Seventy-nine asymptomatic sciatic nerves and 147 hamstring muscles (25 males, 24 females) aged 18-50 years were evaluated. One chiropractic radiologist with 4.5 years of US experience performed the evaluations. Sciatic nerves were sampled along the posterior thigh at four sites obtaining CSA, SWE, and algometry. All three hamstring muscles were sampled at two sites utilizing SWE and algometry. Descriptive statistics, two-way ANOVA, and rater reliability were assessed for data analysis with p ≤ 0.05. RESULTS: A significant decrease in sciatic CSA from proximal to distal was correlated with increasing BMI (p < 0.001). Intra-rater and inter-rater reliability for CSA was moderate and poor, respectively. Elastographic values significantly increased from proximal to distal with significant differences in gender and BMI (p = 0.002). Sciatic PPT significantly decreased between sites 1 and 2, 1 and 3, and 1 and 4. Significant correlation between gender and PPT was noted as well as BMI (p < 0.001). Hamstring muscle elastographic values significantly differed between biceps femoris and semitendinosus (p < 0.001) and biceps femoris and semimembranosus (p < 0.001). All three hamstring muscles demonstrated increased PPT in males compared to females (p < 0.001). In addition, PPT of the biceps femoris correlated with BMI (p = 0.02). CONCLUSION: High-resolution US provided useful metrics of sciatic nerve size and biomechanical properties. PPT for the normal sciatic nerve and hamstring muscles was obtained for future clinical application.

Sonoelastography of the trunk and lower extremity muscles in a case of Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) is a rare genetic disorder typically presenting with muscle weakness and reduced tone of trunk and lower extremities. The sonoelastographic properties of DMD are poorly understood. We describe sonoelastographic characteristics of a patient's trunk and lower extremity musculature. An 8-year-old male presented with a 5-year history of DMD. Sonoelastographic measures of the gluteus maximus and medius, lumbar erector spinae, rectus abdominis, rectus femoris, biceps femoris, tibialis anterior, medial and lateral gastrocnemius muscles were obtained. Sonoelastography demonstrated increased elasticity by elevated kiloPascals (kPa) across all muscles, except the lumbar erector spinae. Patient values were compared to an age-matched healthy control. These abnormal sonoelastographic findings reflected the pathological mechanical properties of DMD. Sonoelastography was valuable for characterizing the mechanical properties of normal and abnormal muscle tissue. There is limited information on the sonoelastography application to DMD. Sonoelastography may serve as a useful measure for diagnosis and monitoring clinical outcomes for DMD.

Rectus abdominis muscle tear diagnosed with sonography and its conservative management.

PURPOSE: This is a rare case of a post-traumatic rectus abdominis muscle tear in an adolescent female diagnosed by ultrasonography (US). Conservative management is also described. METHODS: A 14-year-old female presented to a chiropractic clinic with extreme pain and tenderness in the right lower quadrant (RLQ) after post-plyometric power kneel box jumps. Movement aggravated her pain and she demonstrated active abdominal guarding with RLQ palpation. Ultrasonography revealed a subacute Grade 2 right rectus abdominis muscle tear, without evidence of hyperemia or a hematoma. Following the diagnosis of a right rectus abdominis muscle tear, she was treated with spinal manipulation and a course of musculoskeletal rehabilitation directed at truncal stabilization. RESULTS: After treatment, the patient was able to return to play 5 week post-injury without any pain or discomfort. A follow-up US at 3 months provided evidence of muscle healing without complications. CONCLUSION: This case demonstrates the diagnosis of a rare rectus abdominis muscle tear managed conservatively. To our knowledge, less than a dozen cases are reported using US in the evaluation and diagnosis of a rectus abdominis tear.

Neural Arch Bone Marrow Edema and Spondylolysis in Adolescent Cheerleaders: A Case Series.

OBJECTIVE: Spondylolysis is 1 of the most common sources of low back pain in children and adolescents; however, there is still a great deal of confusion in regard to etiology, clinical presentation, and diagnostic imaging findings. It is imperative for clinicians to recognize that persistent low back pain is strongly indicative of spondylolysis, especially in high-performance athletes. This case series demonstrates a comprehensive diagnostic spectrum of spondylolysis and its treatment in 2 competitive adolescent cheerleaders. CLINICAL FEATURES: In case 1, a 12-year-old female competitive cheerleader presented with a gradual onset of subacute low back pain. Comprehensive clinical examination indicated imaging studies that identified bilateral L5 grade 1 stress reaction, consisting of neural arch bone marrow edema (BME). Treatment included spinal adjustments, rehabilitation, and myofascial therapy. In case 2, 15-year-old female competitive cheerleader presented with insidious chronic low back pain that was provocative with extension. Magnetic resonance imaging revealed a left L5 grade 1 pars interarticularis stress reaction. Computed tomography demonstrated right L5 pars grade 3 and left L5 healing spondylolysis. Treatment included spinal adjustments and rehabilitation exercises. She was also seen by a physical therapist who prescribed a lumbar spine flexion brace. INTERVENTION AND OUTCOME: Diagnosis of BME and spondylolysis led to temporary cessation of cheerleading activities in cases 1 and 2. The individual in case 1 self-discharged with a list of rehabilitation exercises and was lost to follow-up. The individual in case 2 was able to return to sport pain free approximately 5 weeks after seeking treatment. CONCLUSION: Spondylolysis is common in adolescent athletes, and the presence of BME precedes spondylolysis. Primary spine providers could consider this diagnosis in any adolescent, especially an athlete, who has persistent low back pain. Timely diagnosis will optimize treatment outcomes.