Suprascapular nerve compression

 

Suprascapular nerve

 

C5, 6 from upper trunk

 

Suprascapular notch

- under superior transverse scapular ligament

- suprascapular artery and vein run over this ligament

- supplies supraspinatus after passing under ligament

 

Spinoglenoid notch

- lateral border spinous process

- under spinoglenoid ligament

- supplies infraspinatus

 

Suprascapular Ganglion Coronal MRISuprascapular Nerve Sagittal MRI 1Suprascapular Nerve Sagittal MRI 2

 

Sites of Compression / Injury

 

Suprascapular notch

- weakness and wasting of both supraspinatus & infraspinatus

- trauma most common cause - direct blow / clavicle fracture / scapula fracture

- athletes / repetitive overhead motion

 

Spinoglenoid notch

- weakness and wasting of infraspinatus

- spinoglenoid cyst - superior labral tear / posterosuperior labral tear

- acts as one way valve

 

History

 

Posterior shoulder pain

Weakness

 

Examination

 

Weakness

Atrophy supraspinatus / infraspinatus

 

MRI 

 

Spinoglenoid cyst + labral tear

 

Spinoglenoid cyst Coronal MRISpinoglenoid Cyst Sagittal MRI

Spinoglenoid cyst

 

Spinoglenoid Cyst MRI Axialslap

Spinoglenoid cyst with SLAP tear and posterosuperior labral tear

 

EMG 

 

Demonstrate denervation SS/IS or IS alone

 

Spinoglenoid Cyst

 

Causes

 

Posterosuperior labral tears

SLAP tears

 

Options

 

Cyst decompression + labral repair

Labral repair alone

 

Results

 

Posterosuperior labral tears

 

Schroder et al JBJS Am 2008

- 42 patients with posterosuperior labral tear and spinoglenoid cyst

- posterior labral repair without cyst decompression

- cyst resolved in 88% on MRI and smaller in remainder

- all patients satisfied with outcome

 

SLAP tears

 

Schroeder et al Arthroscopy 2018

- systematic review of 160 SLAP tears with spinoglenoid cyst

- no difference in outcome between decompression + labral repair versus labral repair alone

 

Cyst decompression

 

Options

 

Through labral tear

Glenohumeral approach - posterior capsulotomy above IGHL

Subacromial approach - between supraspinatus and infraspinatus 

 

Glenohumeral joint approach

 

Arthroscopy techniques spinoglenoid cyst decompression

 

Vumedi spinoglenoid cyst decompression video

 

Posterior Shoulder Capsulotomy to decompress cyst

 

Subacromial space approach

 

Ghodadra et al Arthroscopy 2009

- subacromial space

- identify spine of scapula

- dissect between infraspinatous and supraspinatous

- accessory posterior portal, retract IS and nerve

- decompress with shaver

 

Shoulder Subacromial Space Spinous ProcessSubacromial Spinous Process 1

 

Suprascapular Notch Impingement / Division of Suprascapular ligament 

 

Indication

 

Weakness atrophy of supraspinatus / infraspinatus without cuff tear

- massive irreparable cuff tear with intractable pain

 

Options

 

Open / arthroscopic

 

Results

 

Lafosse et al Arthroscopy 2007

- 10 patients with clinical and EMG evidence of suprascapular nerve compression

- no complications

- good clinical outcome in all patients

 

Open Technique

- incision along spine of scapular

- sharply elevate trapezius off spine off scapula

- SS reflected inferiorly to expose notch

- preserve superior NV bundle

- suprascapular artery lies above ligament, (branch of Subclavian Artery)

- divide ligament

 

Arthroscopic Technique

 

Vumedi suprascapular nerve decompression video

 

Standard posterior portal

- subacromial portal to debride cuff and identify base of coracoid as landmark

- find coracoid by following CAL to it

- feel hard bony prominence

 

Anterolateral working portal

- need to be able to work lateral to medial along anterior aspect of humeral head

 

Dissection

- clear space medial to coracoid along subscapularis

- identify the conoid ligament attaching to the base of the coronoid

- medial to this is fatty area with THL

 

SSN Release CoracoidSSN Release Coracoid and CHL

 

Suprascapular portal / accessory Nevasier

- 7cm from posterior edge of acromion

- insert blunt instruments posteriorly from suprascapular portal

- pass under clavicle

- elevates supraspinous muscle

- use blunt trochar to dissect area

 

Anatomy

- will usually see the artery passing over the top of the THL 

- be careful as this runs from subclavian

- can get torrential bleeding

 

Conoid Ligament  SSA over THLSuprascapular artery and transverse scapula ligament

 

Identify transverse ligament

- identify SSN passing under

- divide TSL with scissors from posterior ACJ portal

- whilst retracting SS artery with probe from SSN portal

 

SSN release Divided THLSSN Release Divided TSL