Correlation of suprascapular notch morphology with suprascapular nerve palsy: a 3D-computed tomography study

Keigo Honoki; Naoki Suenaga; Naomi Oizumi; Shintaro Yamane; Chika Yoshioka; Yukiyoshi Hisada; Tomoya Matsuhashi; Jun Kawamata; Yu Ito

doi:10.1016/j.jseint.2022.12.016

Correlation of suprascapular notch morphology with suprascapular nerve palsy: a 3D-computed tomography study

JSES Int. 2023 Jan 10;7(2):316-323. doi: 10.1016/j.jseint.2022.12.016. eCollection 2023 Mar.

Authors

Keigo Honoki^{1

2}, Naoki Suenaga¹, Naomi Oizumi¹, Shintaro Yamane¹, Chika Yoshioka¹, Yukiyoshi Hisada¹, Tomoya Matsuhashi¹, Jun Kawamata³, Yu Ito⁴

Affiliations

¹ Upper Extremity Center of Joint Replacement and Endoscopic Surgery, Hokushin Orthopaedic Hospital, Sapporo, Japan.
² Department of Orthopaedic Surgery, Teine Keijinkai Hospital, Sapporo, Japan.
³ Department of Orthopaedic Surgery, Kaisei Hospital, Obihiro, Japan.
⁴ Department of Rehabilitation, Orthopaedic Hokushin Hospital, Sapporo, Japan.

Abstract

Background: The morphology of the suprascapular (SS) notch is a very important factor in treatment of suprascapular nerve (SSN) palsy. Several studies have reported SS notch morphology in cadavers or using a three-dimensional computed tomography (3D-CT); however, none has reported the distribution of SS notch morphology according to the age group. In addition, the correlation between SS notch morphology and SSN palsy remains unclear. The purposes of this study were to investigate the morphological distribution of the SS notch by age group in a large population and to assess the relationship between SS notch morphology and SSN palsy.

Methods: We studied the 3D-CT images of 1063 shoulders in 1009 patients (mean age, 60.8 years; age range, 14-96 years). There were 53 shoulders with SSN palsy and 1010 shoulders without SSN palsy. Morphology of the SS notch was classified by Rengachary's classification (types I-VI). Shoulders with types I-IV were classified into the nonossified superior transverse scapular ligament (STSL) group (group N) and those with types V and VI into the ossified STSL group (group O).

Results: The Rengachary's classifications of the 1063 shoulders were as follows: type I: n = 113, 10.6%; type II: n = 313, 29.4%; type III: n = 383, 36.0%; type IV: n = 109, 10.3%; type V: n = 107, 10.0%; and type VI: n = 38, 3.6%. Mean age was significantly older in the ossified STSL group, and the age was <40 years for only two shoulders in this group. The Rengachary's classifications of the SSN palsy cases were as follows: type I: 7.5%, II: 24.5%, III: 34.0%, IV: 15.1%, V: 13.2%, and VI: 5.7%. There was no statistical difference in age and sex, Rengachary type, or ossification between SSN palsy and non-SSN palsy cases.

Conclusions: Ossification of the STSL was significantly more common in older patients, which suggests age-related change. In addition, no relation was identified between narrow notch or ossification of the STSL with the onset of SSN palsy.

Keywords: Morphology; Rengachary’s classification; Superior transverse scapular ligament; Suprascapular nerve palsy; Suprascapular notch; Three-dimensional CT.