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Final Program

1151 - Utilization of diagnostic neuromuscular ultrasound for pediatric scapular winging: A case of spinal accessory mononeuropathy in a 4-year-old

Friday, February 28, 2025
5:00 PM - 6:30 PM MST
Case Diagnosis: Right spinal accessory mononeuropathy 

Case Description: A 4-year-old female with a history of right tail of parotid and lymphadenectomy levels 1B –5 with partial sternocleidomastoid excision and reanastomosis of cranial nerve 11 presented to Pediatric Physical Medicine and Rehabilitation for right shoulder pain and dysfunction. Her parents noticed scapular winging and shoulder asymmetry 4 months postoperatively. Sedated electromyography (EMG) revealed ongoing denervation and large motor units in the right upper trapezius muscle, indicating a mild right spinal accessory mononeuropathy. The rhomboids, serratus anterior, and other portions of the trapezius muscle were not evaluated with needle EMG due to safety concerns. Neuromuscular ultrasound (NMUS) revealed significant asymmetry, atrophy, and hyperechogenicity in all portions of the trapezius muscle (upper, middle, and lower) with symmetric muscle echotexture and movement in the bilateral rhomboid and serratus anterior muscles, further demonstrating an even larger involvement of spinal accessory innervated musculature. In this case, ultrasound helped confirm diagnosis and direct therapeutic interventions.

Discussions: NMUS is a useful adjunctive technique to EMG for visualization and evaluation of peripheral nerve and muscle tissues. Sonographic changes have also demonstrated high accuracy with muscle pathology, including in scapular winging. This technique is becoming a more common tool in EMG laboratories and has been validated in children. EMG alone can be limited in pediatrics due to pain tolerance, ability to follow directions, and often need for sedation. Benefits to pediatric NMUS include dynamic imaging, painless performance, higher frequency with improved resolution compared to MRI, and no requirement for sedation. 

Conclusions: Pediatric NMUS contributes high diagnostic value with the ability to direct future therapeutic interventions and augments EMG and clinical examination in the pediatric population.