Arthroscopic Suprascapular Nerve Decompression: A Technique Video

Abstract

Background:

Suprascapular neuropathy is an uncommon but treatable cause of shoulder pain and dysfunction. The tortuous course of the suprascapular nerve puts it at risk for entrapment, particularly at the suprascapular and spinoglenoid notches. This video presents a reproducible method for suprascapular nerve decompression at the suprascapular notch.

Indications:

Massive rotator cuff tears, compressive masses, or ligament hypertrophy warrants prompt intervention to prevent subsequent denervation in the face of suprascapular neuropathy. In the absence of these pathologies, a trial of conservative management is advised. Patients who have unsuccessful conservative management and evidence of worsening weakness, atrophy, and denervation by electromyography are indicated for surgical intervention.

Technique Description:

Standard posterior, anterior, lateral, and anterolateral portals are established. The subdeltoid space is dissected following the coracoacromial (CA) ligament to the base of the coracoid to identify the transverse scapular ligament. In the presented case, the CA ligament has been debrided from a previous surgery, so an intra-articular approach was employed, opening the rotator interval to reach the base of the coracoid. A Neviaser portal is made for blunt dissection around the suprascapular notch, with care taken to protect the neurovasculature. A second medial Neviaser portal is used to pass a Kerrison to release the transverse scapular ligament. Nerve adhesions are then gently released with a probe.

Results:

A systematic review of 276 suprascapular nerve decompressions demonstrated good outcomes in terms of pain relief and function, and all athletes in the review returned to sport. A case series of 112 arthroscopic decompressions at the suprascapular notch found that patients achieved significant improvement in pain and strength, and none resulted in serious complications. These outcome studies support a level 4 video publication level of evidence.

Discussion/Conclusion:

The presented arthroscopic decompression technique treats suprascapular nerve entrapment at the suprascapular notch. Patients can expect to achieve a satisfactory outcome.

Patient Consent Disclosure Statement:

The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Graphical Abstract

This is a visual representation of the abstract.

Video Transcript

Background

We present our technique for arthroscopic suprascapular nerve decompression. The authors have no relevant disclosures for this presentation. This is an overview of our presentation.

Suprascapular neuropathy, while not common, is a notable source of shoulder pain and dysfunction. Nerve injury typically occurs due to focal entrapment, traction, or trauma. ⁵

The tortuous course of the suprascapular nerve puts it at risk for entrapment, particularly at the suprascapular and spinoglenoid notches, where its movement is limited by bone and ligamentous structures. ⁷ The presence or absence of supraspinatus muscle pathology aids in localizing the nerve lesion.^7,9

Initially, conservative management is recommended in the absence of trauma or compressive mass. Surgery should be considered in cases of a failure of conservative measures and evidence of worsening function, muscle atrophy, and impaired nerve conduction. If electromyography findings are inconclusive, ultrasound-guided diagnostic injection can aid in the diagnosis of suprascapular neuropathy.^7,9

Indications

We present a case of a 28-year-old woman who is an avid weightlifter. She has had persistent left shoulder weakness 1 year following superior labral anterior and posterior (SLAP) debridement, acromioplasty, distal clavicle excision, and biceps tenodesis. She reports functioning at 70% of normal despite a year of physical therapy. Previous imaging and diagnostic studies demonstrated normal rotator cuff muscle bulk on magnetic resonance imaging (MRI) and normal nerve conduction tests.

Physical examination was notable for weakness with supraspinatus, infraspinatus, and hornblower testing, as well as positive Neer and Hawkin impingement tests.

Shoulder anteroposterior (AP) and scapular Y view radiographs were unremarkable. MRI showed increased signals and a loss of muscle bulk of the supra- and infraspinatus muscle bellies. There were no abnormal focal masses or cystic changes along the course of the suprascapular nerve.

The change in signal and muscle bulk is clearly visible compared to the MRI 1 year ago before her SLAP debridement, acromioplasty, and distal clavicle excision. This change is classically seen in the setting of suprascapular nerve compression. ¹⁰ Nerve conduction studies revealed severe neuropathy involving both the supraspinatus and infraspinatus.

Involvement of both muscles localized the lesion proximal to the supraspinatus branch-off. With evidence of worsening atrophy and neuropathy, we recommended surgical intervention. ⁷

Technique Description

We prefer to perform this procedure in the beach-chair position with the arm controlled by a pneumatic limb positioner. The surgeon for this procedure was right-hand dominant.

We started with a diagnostic arthroscopy with a 30° arthroscope. Intra-articular pathology is addressed through a standard anterior portal 1 to 2 cm lateral to the coracoid. We then entered the subacromial space through a standard posterior portal and made an anterolateral working portal. Subacromial bursal tissue is debrided to aid in visualization through an anterolateral portal. We then switched from a posterior to a lateral viewing portal. The subdeltoid space is opened with use of a radiofrequency wand and shaver. We typically follow the coracoacromial (CA) ligament to identify the coracoid, ⁸ but in this case, the CA ligament was debrided at the time of the previous subacromial decompression. It can be challenging to identify the coracoid from the subacromial space without the aid of the CA ligament, so in these settings, we reenter the glenohumeral joint and open the rotator interval to identify the coracoid. We released the rotator interval back to the base of the coracoid, which allows for easier identification from the subacromial space. We then made a Neviaser portal while viewing intra-articularly and introduced a switching stick.

The arthroscope is then moved back to the lateral portal to view from the subacromial space. Once the coracoid is identified in the subacromial space, we release any adhesions along the leading edge of the supraspinatus posteriorly with the coracoid anteroinferior as we move medially toward the suprascapular notch. We use a switching stick through our Neviaser portal to retract the supraspinatus posteriorly. We then made a second portal 2 cm medial to our Neviaser portal to place a second switching stick to bluntly dissect the transverse scapular ligament, ³ with the suprascapular artery running over the top of the ligament and the suprascapular nerve running underneath. We used a shaver to gently debride any tissue that may impede visualization once we have identified the neurovascular structures. Next, we utilized a Kerrison through our medial Neviaser portal to release the ligament. With a probe, we mobilize the nerve to ensure all adhesions have been released and to confirm that there are no other sources of compression.

Pearls of this technique include following the CA ligament from subacromial (SA) space to reach the coracoid. ⁸ If the CA ligament is absent, the rotator interval can be exposed from an intra-articular approach. This allows for easier identification of the base of the coracoid and the adjacent suprascapular notch. We use a switching stick through the Neviaser portal to retract the supraspinatus muscle belly. The switching stick can also reflect the supraspinatus nerve away from where the ligament is being cut. We then establish an accessory portal, just medially, ³ to release the transverse scapular ligament with a Kerrison.^1,4 This approach facilitates access to the ligament. The switching stick assists with the blunt dissection of adhesions surrounding the suprascapular nerve.

Results and Discussion

Pitfalls: We do not recommend performing a notchplasty with a bur, as this can elicit scarring and subsequent nerve compression. ⁴ Furthermore, avoid sharp dissection around the nerve.

Patients are fitted with a sling postoperatively. Physical therapy initially focuses on passive and active assisted range of motion. By 4 weeks, patients have begun light isometrics and passive stretching. Resistance training commences at 8 weeks, and return to sport is expected by 3 months postoperatively based on return of muscle strength.

Momaya et al ⁶ published a systematic review studying outcomes of 276 suprascapular nerve decompressions, at least one-fourth of which were decompressions at the suprascapular notch. Patients achieved good outcomes in terms of pain and function, and all athletes in this review returned to their respective sport.

Davis et al ² published a case series of 112 arthroscopic decompressions at the suprascapular notch. Patients achieved significant improvement in pain and strength, and none resulted in serious complications. The most common complication was sympathetic dystrophy, which occurred in 12% of patients. These patients were effectively treated with stellate ganglion blocks.

In summary, suprascapular neuropathy is an uncommon but significant cause of shoulder pain and dysfunction. Although arthroscopic decompression can be technically challenging, patients can be expected to achieve satisfactory outcomes.

These are our references. Thank you for taking the time to watch our video.