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
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
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
- 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
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
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
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
Identify transverse ligament
- identify SSN passing under
- divide TSL with scissors from posterior ACJ portal
- whilst retracting SS artery with probe from SSN portal