Suprascapular Nerve Palsy G56.80 354.8

ICD-9	Classification / Treatment
Etiology / Natural History	Associated Injuries / Differential Diagnosis
Anatomy	Complications
Clinical Evaluation	Follow-up Care
Xray / Diagnositc Tests	Review References

synonyms: Spinoglenoid Notch Cyst,suprascapular nerve palsy, suprascapular neuropathy

Suprascapular Nerve Palsy ICD-10

Suprascapular Nerve Palsy ICD-9

Suprascapular Nerve Palsy Etiology / Epidemiology / Natural History

Rare.
More common in volleyball players (Fehrman DA, JBJS 1987;69A:260), baseballpitchers.
May result from stretch injury (overhead activites), repetitive microtrauma, direct compression of the nerve or indirect injury to the vascular supply to the nerve.
More common in men than women.
Natural history of ganglion cysts about the shoulder is unknown. May enlarge over time with progressive weakness and loss of function.

Suprascapular Nerve Palsy Anatomy

Paralabral ganglion cyst can cause compression on the transverse scapular ligament of the spinoglenoid notch.
Proximal compression of the suprascapular nerve (scapular notch) causes denervation of the supraspinatus and infraspinatus.
Distal compression (spinoglenoid notch) causes denervation of the infraspinatus only.
See also Suprascapular nerve anatomy.

Suprascapular Nerve Palsy Clinical Evaluation

Weakness and dull aching posterior shoulder pain. Supraspinatus denervation causes abduction weakness. Infraspinatus causes external rotation weakness.
Evaluate for infraspinatus and / or supraspinatus atrophy.
External Rotation lag signwill indicate infraspinatus weakness.
Jobe's testmay indicated supraspinatus weakness.
May have positive evaluation findings for SLAP Tear.

Suprascapular Nerve Palsy Xray / Diagnositc Tests

AP, scapular lateral and axillaryviews generally normal.
MRI: Paralbral cysts are generally located medial to the postersuperior glenoid within the spinoglenoid notch; appear as well-defined, smoothly marginated high signal intensity on T2 images. Chronic denervation is associated with infraspinatus and supraspinatus muscle atrophy. (Tirman PF, Radiology 1994;190:653), (Inokuchni W, JSES 1998;7:223).
EMG/NCV: indicated to confirm diagnosis. Demonstrates denervation potentials in the infraspinatus and/or supraspinatus muscles.

Suprascapular Nerve Palsy Classification / Treatment

Unidentifiable lesion: organized physical therapy. Pain and weakness may take > one year to reach maximum improvement. PT to maintain ROM, strengthen RTC, deltoid and periscapular muscles. (Martin SD, JBJS 1997;79A:1159).
Spinoglenoid notch cyst: arthroscopic decompression with repair of any labral injury to prevent recurrence. (Youm T, Arthroscopy 2006;22:548), (Fehrman DA, Arthroscopy 1995;11;727), (Moore TP, JSES 1997;5:455). Code as: 29823(arthroscopy shoulder; with extensive debridement) or 29807(arthroscopy shoulder with SLAP repair)
Supracapular notch compression: shoulder arthroscopy followed by open decompression and release of the hypertrophic transverse scapular ligament.
Ultrasound or CT guided aspiration has also been previously reported.

Open Spinoglenoid Notch Decompression Technique

Perform shoulder arthroscopy and repair any labral lesion first.
4-6cm longitudinal incision 3cm medial to the posterolateral corner of the acromion.
Dissect under 2.5x/3.5x loop magnification down to deltoid. Split deltoid fibers beginning at the scapular spine.
Retract superior edge of the infraspinatus inferiorly.
Identify suprascapular nerve, suprascapular artery and spinoglenoid notch cyst in the spinoglenoid notch.
Excise the cyst.
Irrigate.
Repair deltoid fascia.
Close in layers.

Suprascapular Nerve Palsy Associated Injuries / Differential Diagnosis

SLAP Tear/ Labral tears: >95% of spinoglenoid notch cysts are associated with posterior-superior labral tears.
Rotator Cuff Tear.

Suprascapular Nerve Palsy Complications

Suprascapular Nerve Palsy Follow-up Care

7-10 Days post-op: start PT. Avoid stress the superior labrum for 6 wks if concomitant SLAP/labral repair was done.
Supraspinatus and infraspinatus atrophy often persist, even after decompression of associated cysts.
Spinoglenoid notch cyst decompression generally resolves associated shoulder pain.
100% successful outcomes for arthroscopic labral repair without formal cyst excision (Youm T, Arthroscopy 2006;22:548) .

Suprascapular Nerve Palsy Review References