Nerve Lesions: Suprascapular, Axillary, Thoracic Outlet, and



Nerve Lesions: Suprascapular, Axillary, Thoracic Outlet, and




S. H. Kozin: Associate Professor, Department of Orthopaedic Surgery, Temple University and Hand Surgeon, Shriners Hospitals for Children, Philadelphia, Pennsylvania.











TABLE 33-1 SEDDON’S CLASSIFICATION OF NERVE INJURY



















Type


Definition


Outcome


Neuropraxia


Interruption of nerve conduction; some segmental demyelination; axon continuity intact


Reversible


Axonotmesis


Axon continuity disrupted; neural tube intact


Wallerian degeneration; incomplete recovery


Neurotmesis


Complete disruption of nerve continuity; loss of axons and neural tubes


No spontaneous recovery; surgery required







Figure 33-1 Suprascapular nerve passes below the transverse scapular ligament and around lateral margin of the scapular spine (spinoglenoid notch).







Figure 33-2 Classification of suprascapular notch morphology. In type I, the entire superior border of the scapula shows a depression (8% of specimens). In type II, there is a wide, blunted, V-shaped notch (31%). In type III, the notch is symmetrical and U-shaped (48%). In type IV, there is a very small V-shaped notch (3%). Type V is similar to type III but with partial ossification of the medial portion of the transverse scapular ligament (6%). In tye VI, the transverse scapular ligament is completely ossified, resulting in a foramen of variable size (4%). (Adapted from Rengachary SS, Burr D, Lucas S, et al. Suprascapular entrapment neuropathy: a clinical, anatomical, and comprehensive study. Part 2: anatomical study. Neurosurgery 1979;5:447.)








TABLE 33-2 CAUSE OF SUPRASCAPULAR NEUROPATHY


















Repetitive microtrauma


Overhead activities (e.g., volleyball, tennis, weight lifting)


Direct trauma


Glenohumeral dislocation, scapular fracture, proximal humerus fracture, iatrogenic injury (e.g., posterior shoulder surgery, distal clavicle resection, transglenoid arthroscopic shoulder stabilization, and rotator cuff surgery)


External compression


Patient positioning during spine surgery



Glenohumeral ganglion or cyst


Infection


Brachial neuritis (Parsonage-Turner syndrome)








Figure 33-3 Magnetic resonance imaging (MRI) of glenohumeral cyst emanating from the posterior-superior capsularlabrum junction and compressing the suprascapular nerve before innervation of the infraspinatus muscle.






Figure 33-4 A 30-year-old woman with right suprascapular notch neuropathy and diffuse atrophy of both the supraspinatus and infraspinatus muscles.







Figure 33-5 Superior trapezius-splitting approach for decompression of suprascapular notch neuropathy.






Figure 33-6 Posterior approach to the shoulder for isolation of the suprascapular nerve and excision of glenohumeral cyst.








Figure 33-7 Posterior view of quadrilateral space with axillary nerve and posterior humeral circumflex artery.








TABLE 33-3 CAUSE OF AXILLARY NEUROPATHY















Repetitive Microtrauma


Quadrilateral Space
Syndrome


Direct trauma


Glenohumeral fracture and/or dislocation


Iatrogenic injury (e.g., shoulder instability surgery, rotator cuff surgery, arthroscopy, and capsular shrinkage)


Penetrating trauma


Gunshot injury


Infection


Brachial neuritis (Parsonage-Turner syndrome)


External compression


Tumor or aneurysm

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Jul 15, 2016 | Posted by in ORTHOPEDIC | Comments Off on Nerve Lesions: Suprascapular, Axillary, Thoracic Outlet, and
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