Anatomical considerations for safe scapular resection in snapping scapula syndrome

Abstract

The resection of the superomedial angle of the scapula in snapping scapula syndrome is associated with potential risk of injury to the suprascapular nerve. The aim of the present study was to determine the distance of site of resection on the upper border of the scapula from the suprascapular notch during arthroscopic resection of the superomedial angle using standard superior Bell's and medial portals at the middle of medial border. The study was conducted on 92 intact dry adult scapulae of unknown sex. The junction of the medial two-thirds and the lateral one-third of an imaginary line joining the superomedial angle and the lateral margin of the acromion was marked as superior Bell's portal. The middle of the medial border was considered as the arthroscopic resection target. The site of resection on the upper border was found out with the help of these two points and other relevant measurements were also taken. The distance between the suprascapular notch and the lateral edge of resection on the upper border of the scapula was more than 10mm in 85.9% cases and less than 10mm in 14.1%. A statistically significant positive correlation was found between this distance and the distance between the superior angle and acromion angle of the scapula. Our study suggests that during arthroscopic resection using superior Bell's portal and medial portal, suprascapular notch hence the suprascapular nerve would have safe margin of more than 10mm from the resection site on upper border in 85.9% cases and would be vulnerable to injury in 14% cases. The procedure would be safer in patients with a wider scapula.