Nerve ultrasound findings in two cases of spinal accessory nerve palsy

Comparison of ultrasound with electrodiagnosis of scapular winging: A prospective case control study

OBJECTIVE

Compare high-resolution ultrasound (HRUS) and electrodiagnostic examination (EDX) in the diagnostic workup of patients with scapulae alatae.

METHODS

27 patients with scapulae alatae and 41 healthy subjects (HS) and underwent a standardized clinical examination (CEX), EDX and HRUS. We measured the thickness of the serratus anterior (SER), rhomboid major and trapezius muscles and the diameter of the long thoracic (LTN), dorsal scapular and spinal accessory nerves (SAN).

RESULTS

Twenty patients showed medial winging and six patients showed lateral winging on CEX. One patient had both lateral and medial winging. In patients with medial winging, the SER muscle was thinner and the LTN diameter was larger on the symptomatic side compared with the asymptomatic side and with the dominant side in HS. In this group, both EDX and HRUS detected abnormalities of SER muscle/ LTN with sensitivity of 65%, and with specificity of 100% and 57%, respectively. EDX and HRUS detected abnormalities of the trapezius muscle/ SAN with sensitivity of 60% and 40%, and specificity of 91%, and 86 % a, respectively. There was no significant difference between the two methods.

CONCLUSION

HRUS can contribute to the diagnostic workup of scapulae alatae by demonstrating atrophy of muscles and enlargement in nerve diameter.

SIGNIFICANCE

HRUS supplements EDX in the diagnostic workup of scapulae alatae.

Sonographic characteristics of the facial nerve in healthy volunteers

INTRODUCTION

Peripheral nerve ultrasound has become an effective imaging technique. However, imaging of cranial nerves, especially in healthy volunteers, has received minimal attention. The objectives of this study were to describe the sonographic characteristics of the facial nerve and to establish average values of its diameter.

METHODS

The extra-cranial part of the facial nerve was scanned bilaterally along its longitudinal axis inside the parotid gland using a 13-MHz probe in 50 healthy adults. The diameter was measured at the nerve's thickest region.

RESULTS

The facial nerve appeared as a thin, tubular, hypoechoic structure inside the parotid gland. The mean facial nerve diameter was 0.5 ± 0.1 mm, and the mean side-to-side difference in diameter was 0.1 ± 0.1 mm.

CONCLUSIONS

The average facial nerve diameter values may provide help with identification of nerve abnormalities using ultrasound.

Role of Sonography in Surgical Decision Making for Iatrogenic Spinal Accessory Nerve Injuries: A Paradigm Shift

The spinal accessory nerve (SAN) is susceptible to iatrogenic injury in the posterior cervical triangle. Early diagnosis and management of suspected SAN transection injuries are crucial in the restoration of shoulder stability and function. Although neurologic examination and electrodiagnostic testing can assess SAN function, they cannot assess nerve continuity. We report the use of sonography to prospectively evaluate the SAN in 6 patients with suspected iatrogenic SAN injury. Sonography directly visualized SAN transection in 4 cases, whereas sonographic findings were reported as "probable" transection in the fifth case and was nondiagnostic in the sixth case in the setting of extensive scarring.

Neuromuscular ultrasound of cranial nerves

Ultrasound of cranial nerves is a novel subdomain of neuromuscular ultrasound (NMUS) which may provide additional value in the assessment of cranial nerves in different neuromuscular disorders. Whilst NMUS of peripheral nerves has been studied, NMUS of cranial nerves is considered in its initial stage of research, thus, there is a need to summarize the research results achieved to date. Detailed scanning protocols, which assist in mastery of the techniques, are briefly mentioned in the few reference textbooks available in the field. This review article focuses on ultrasound scanning techniques of the 4 accessible cranial nerves: optic, facial, vagus and spinal accessory nerves. The relevant literatures and potential future applications are discussed.