Three-Dimensional Morphological Analysis of the Suprascapular Notch in Patients with Arthroscopic Rotator Cuff Repair

The morphology of the suprascapular notch (SSN) and the ossification of the superior transverse suprascapular ligament (STSL) are risk factors for injury of the suprascapular nerve (SN) during arthroscopic shoulder procedures. The purpose of the current study was to compare preoperative clinical and radiologic characteristics between patients with and without STSL ossification and to evaluate SSN morphology in patients who underwent arthroscopic rotator cuff repair using a 3-dimensional (3D) reconstructed model.

Patients who underwent arthroscopic rotator cuff repair and were given a computed tomography (CT) scan from March 2018 to August 2019 were included in this study. Patients were divided into 2 groups: those without STSL ossification (group I) and those with STSL ossification (group II). Tear size of the rotator cuff and fatty infiltration of rotator cuff muscles were assessed in preoperative magnetic resonance imaging. The morphology of the SSN was classified following Rengachary's classification. The transverse and vertical diameters of the SSN and the distances from anatomical landmarks to the STSL were measured. All measurements were completed using a 3D CT reconstructed scapula model.

A total of 200 patients were included in this study. One hundred seventy-eight patients (89.0%) without STSL ossification were included in group I, and 22 patients (11.0%) with STSL ossification were included in group II. Group II showed a significantly advanced age (61.0 ± 7.4 vs. 71.0 ± 7.3 years, p < 0.001) and a shorter transverse diameter of SSN (10.7 ± 3.1 mm vs. 6.1 ± 3.7 mm, p < 0.001) than group I. In the logistic regression analysis, age was an independent prognostic factor for STSL ossification (odds ratio, 1.201; 95% confidence interval, 1.112-1.296; p < 0.001). Patients in type VI showed significantly shorter transverse diameters than other types (p < 0.001). The patient with type I showed a significantly shorter distance from the articular surface of the glenoid to the SSN than those with other types (p < 0.001).

In the 3D morphological analysis, age was the independent factor associated with STSL ossification in patients who underwent arthroscopic rotator cuff repair. Type VI showed significantly shorter transverse diameters than other types. Type I showed a significantly shorter distance from the articular surface of the glenoid to the SSN than other types.