A new approach for endoscopic neurolysis of the suprascapular nerve at the spinoglenoid notch: A preliminary cadaver study

Risk of suprascapular nerve injury in open Trillat procedure: an anatomical study

PURPOSE

The open Trillat Procedure described to treat recurrent shoulder instability, has a renewed interest with the advent of arthroscopy. The suprascapular nerve (SSN) is theoretically at risk during the drilling of the scapula near the spinoglenoid notch. The purpose of this study was to assess the relationship between the screw securing the coracoid transfer and the SSN during open Trillat Procedure and define a safe zone for the SSN.

METHODS

In this anatomical study, an open Trillat Procedure was performed on ten shoulders specimens. The coracoid was fixed by a screw after partial osteotomy and antero-posterior drilling of the scapular neck. The SSN was dissected with identification of the screw. We measured the distances SSN-screw (distance 1) and SSN-glenoid rim (distance 2). In axial plane, we measured the angles between the glenoid plane and the screw (α angle) and between the glenoid plane and the SSN (β angle).

RESULTS

The mean distance SSN-screw was 8.8 mm +/-5.4 (0-15). Mean α angle was 11°+/-2.4 (8-15). Mean β angle was 22°+/-6.7 (12-30). No macroscopic lesion of the SSN was recorded but in 20% (2 cases), the screw was in contact with the nerve. In both cases, the β angle was measured at 12°.

CONCLUSION

During the open Trillat Procedure, the SSN can be injured due to its anatomical location. Placement of the screw should be within 10° of the glenoid plane to minimize the risk of SSN injury and could require the use of a specific guide or arthroscopic-assisted surgery.

Arm Function After Arthroscopic Decompression of the Suprascapular Nerve at the Spinoglenoid Notch and Suprascapular Notch in Volleyball Players

Background

Suprascapular nerve (SSN) entrapment in volleyball players leads to infraspinatus (ISP) muscle atrophy and weakness of abduction and external rotation (ER) of the shoulder.

Purpose

To assess functional outcome after arthroscopic extended decompression of SSN in the spinoglenoid notch and suprascapular notch in a group of volleyball athletes.

Study Design

Case series; Level of evidence, 4.

Methods

Volleyballers who underwent arthroscopic SSN decompression were analyzed retrospectively. Assessment tools consisted of range of motion and ER strength on Lovett scale and postoperative ER strength measured by dynamometer, Constant-Murley score (CMS), and visual evaluation of ISP muscle recovery by assessing muscle bulk.

Results

The study included 10 patients (9 male and 1 female). The mean age was 25.9 years (range, 19-33) and mean follow-up was 77.9 months (range, 7-123). The mean range of postoperative ER at 90° of abduction (ER2) was 105.6° (88°-126°) and 108.5° (93°-124°) for the contralateral side, while ER2 strength was 8 ± 2.6 and 12.65 ± 2.8 kg (P < .01) respectively. Mean CMS was 89.9 (84-100). In 5 cases, there was complete recovery of ISP muscle atrophy whereas 2 patients had partial recovery and 3 had none.

Conclusion

Arthroscopic SSN decompression in volleyball players improves shoulder function, but results of ISP recovery and ER strength are variable.

The Evaluation and Management of Suprascapular Neuropathy

Suprascapular neuropathy is a potential source of shoulder pain and functional limitation that can present secondary to various etiologies including entrapment or compression. Cystic lesions arising from a labral or capsular tear can compress the nerve along its course over the scapula. Nerve traction is theorized to arise from chronic overhead athletics or due to a retracted rotator cuff tear. The diagnosis of suprascapular neuropathy is based on a combination of a detailed history, a comprehensive physical examination, imaging, and electrodiagnostic studies. Although the anatomic course and variations in bony constraint are well understood, the role of surgical treatment in cases of suprascapular neuropathy is less clear. Recent reviews on the topic have shed light on the outcomes after the treatment of suprascapular neuropathy because of compression, showing that surgical release can improve return to play in well-indicated patients. The incidence of compressive neuropathy is quite high in the overhead athletic cohort, but most patients do not show clinically relevant deficiencies in function. Surgical release is therefore not routinely recommended unless patients with pain or deficits in strength fail appropriate nonsurgical treatment.

Morphological measurements and classification of the spinoglenoid notch: A three-dimensional reconstruction of computed tomography in the Chinese population

BACKGROUND

The spinoglenoid notch (SGN) is the second most common location for suprascapular nerve (SN) entrapment; however, there are few relative morphological reports on this condition. Hence, the present morphological study mainly explored the anatomical structure and classification of the SGN and the relationship with entrapment of SN.

MATERIALS AND METHODS

Four hundred seventy-eight scapulae were analysed thoroughly and systematically in this study. Anatomical structure and classification of the SGN were observed and measured by a three-dimensional (3D) reconstruction of computed tomography (CT). The measurement results were then analysed and recorded.

RESULTS

Chinese scapulae were classified into three types at the SGN, and it was found that left scapulae had deeper SGN than right ones. Then, significant differences were also noted between sexes. Men had thicker, wider and deeper SGN than women. Type II (small U, 46.04%) was the most common. Type I (large U) was the widest (15.67±1.43mm) and deepest (13.71±2.39mm) compared with other types. Lastly, no significant differences in the above criteria were found in other measurements.

CONCLUSIONS

These morphological measurements of the SGN may help to improve the diagnosis and successful treatment rate of the surgery for the SN entrapment, but the relative clinical trial is necessary to support it.