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Suprascapular Nerve Injury

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Other Names

  • Suprascapular Neuropathy
  • Suprascapular Neuropraxia
  • SSN

Background

Epidemiology

  • Prevalence, incidence large unknown
  • Zehetgruber et al: 88 cases in the literature from 1959 to 2001[1]
  • Prevalence estimated to be between 12-33% in athletes, 8-100% in patients with rotator cuff tears[2]

Posterior view of the scapula

Pathophysiology

  • Challenging diagnostic entity due to vague symptoms, co-existence of other conditions[3]

Compressive

Noncompressive

  • Generally considered idiopathic
  • Sports with repetitive overhead activities (volleyball)
    • Up to 30% of volleyball players have asymptomatic infraspinatus atrophy, weakness[4]
  • Typically affects infraspinatous
  • Good prognosis

Pathoanatomy

Associated Conditions


Risk Factors

  • Sports
    • Volleyball
    • Baseball
    • Tennis
    • Basketball
    • Swimming

Differential Diagnosis


Clinical Features

  • General: Physical Exam Shoulder
  • History
    • Deep, dull and aching chronic pain in the superior-posterior-lateral aspect of the shoulder
    • Pain is worse with adduction, internal rotation
    • Subjective weakness, fatigue
  • Physical
    • Observe for atrophy of the supraspinatus, infraspinatus muscles
    • Compression at suprascapular notch: weakness in abduction, external rotation[5]
    • Compression at spinoglenoid notch: weakness in external rotation can be compensated by Deltoid, Teres Minor
    • Atrophy
  • Special Tests
    • Jobe Test: Shoulder abducted to 90°, forward flexion to 30°, internal rotation against resistance
    • Drop Arm Test: Abduct arm to 90° and lower slowly

Evaluation

Radiographs

CT Scan

  • Useful to evaluate for anatomic variants of either notch
  • Can add arthrography

MRI

  • Best overall diagnostic imaging study
  • Ideally with arthrogram to evaluate labrum, paralabral cysts

Ultrasound

  • Can be useful to evaluate rotator cuff
  • Role in suprascapular nerve injury not clearly defined
  • Can be used to guide diagnostic nerve block to suprascapular nerve notch[6]
    • Ultrasound reduced risk of neurovascular injuries as well

EMG/NCS

  • Gold standard for diagnosis
  • Sensitivity 74-91%[7]

Classification

  • Compressive
  • Non-compressive

Management

  • Most management and treatment guidelines driven by case series and retrospective reviews

Nonoperative

  • Generally first line therapy
  • Indications
    • Non-compressive or dynamic causes
    • Absence of space occupying lesion
  • Approach

Operative

  • Indications
    • Failure of conservative management
    • Presence of space occupying lesion
  • Technique
    • Percutaneus drainage (high failure rate)
    • Surgical decompression
    • Repair of underlying injuries (i.e. labral tear, rotator cuff tear, etc)

Rehab and Return to Play

Rehabilitation

  • Emphasis
    • Rotator Cuff
    • Deltoid
    • Periscapular muscles
    • Scapular stabilization

Return to Play

  • Needs to be updated

Complications

  • Weakness
  • Inability to return to sport

See Also


References

  1. Zehetgruber H, Noske H, Lang T, Wurnig C. Suprascapular nerve entrapment. A meta-analysis. Int Orthop 2002;26:339-43.
  2. Shah, Anup A., et al. "Clinical outcomes of suprascapular nerve decompression." Journal of shoulder and elbow surgery 20.6 (2011): 975-982.
  3. Moen, Todd C., et al. "Suprascapular neuropathy: what does the literature show?." Journal of shoulder and elbow surgery 21.6 (2012): 835-846.
  4. Lajtai G, Pfirrmann CW, Aitzetmuller G, Pirkl C, Gerber C, Jost B. The shoulders of professional beach volleyball players: high prevalence of infraspinatus muscle atrophy. Am J Sports Med 2009;37: 1375-83
  5. Gerber C, Blumenthal S, Curt A, Werner CML. Effect of selective experimental suprascapular nerve block on abduction and external rotation strength of the shoulder. J Shoulder Elbow Surg 2007;16: 815-20
  6. Gorthi, Venkat, Young Lae Moon, and Jeong Hoon Kang. "The effectiveness of ultrasonography-guided suprascapular nerve block for perishoulder pain." Orthopedics 33.4 (2010).
  7. Atroshi I, Johnsson R. Evaluation of portable nerve conduction testing in the diagnosis of carpal tunnel syndrome. J Hand Surg Am 1996;21:651-4
Created by:
John Kiel on 14 June 2019 08:35:03
Authors:
Last edited:
13 November 2020 14:07:27
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