Single center experience with hourglass-like constriction neuropathy of suprascapular nerve.

Introduction/aims: Hourglass-like constriction (HGC) may occur in several peripheral nerves. However, data on the prognosis of motor weakness in patients with HGC of the suprascapular nerve (SSN) are limited compared with other nerves. Here, we aimed to describe the clinical and imaging features of HGC of the SSN.

Methods: We retrospectively reviewed patients diagnosed with suprascapular neuropathy using magnetic resonance imaging (MRI) or electrodiagnostic studies over 16 years. After excluding extrinsic causes, patients with HGC of the SSN detected using MRI were included.

Results: Fourteen patients with HGC of the SSN were identified. MRI revealed that all HGCs were located between the origin of the SSN from the upper trunk of the brachial plexus and the suprascapular notch. Seven patients exhibited HGC precisely at the origin of the SSN from the brachial plexus. Four patients showed T2 hyperintensity of the SSN extending to the upper trunk of the brachial plexus or the extraforaminal cervical root. The initial treatments included observation (n = 1), steroid therapy (n = 12), suprascapular notch release (n = 1). Of the 12 patients with a sufficient follow-up period, nine fully recovered from motor weakness of the SSN with non-operative treatments. Six of the nine patients who recovered fully experienced their first clinical improvement more than 6 months after onset.

Discussion: Treatment strategies for HGC differ depending on the affected nerve. For HGC of the SSN, due to the high spontaneous recovery rate observed in our study, conservative management for at least 6 months should be initially considered.