Neurovascular Anatomic Locations and Surgical Safe Zones When Approaching the Posterior Glenoid and Scapula: A Quantitative and Qualitative Cadaveric Anatomy Study.

Purpose: To characterize the qualitative anatomy of posterior scapula structures encountered with the Judet approach and to perform a quantitative evaluation of these structures' anatomic locations, including their relationships to osseus landmarks to identify safe zones. Methods: Twelve fresh-frozen cadaveric shoulders (mean age, 55.2 years; range 41-64 years; 5 left, 7 right) were dissected. A coordinate measuring machine was used to collect the coordinates of anatomic landmarks, structures at risk during surgical approach to the posterior scapula, and the footprints of muscle attachments on the posterior scapula. These coordinates were analyzed for their relationships with clinically relevant anatomy. Results: The suprascapular nerve was a mean of 20.3 mm (18.9-21.7 mm) medial to the glenoid 9-o'clock position. The posterior circumflex artery and vein were a mean of 100.0 mm (92.2-107.7 mm) lateral to along the lateral border of the scapula from the inferior angle of the scapula and a mean of 41 mm (34.2-47.9 mm) medial along the lateral scapular border from the 6-o'clock position on the glenoid rim. The long head of the triceps covers a mean of 132 mm2, and it was found to be contiguous with the glenoid capsule at the 6-o'clock position. Conclusions: A safe zone exists 19 mm medially from the glenoid 9-o'clock position to the suprascapular nerve and a minimum of 34.2 mm medially along the lateral scapular border from the glenoid 6 o'clock to the posterior circumflex scapular artery. Clinical Relevance: The modified Judet approach is a minimally invasive surgery that reduces surgical trauma but necessitates precise knowledge of scapular neurovascular anatomy. Surgeons should be aware of these intervals to help avoid these structures when working near the posterior shoulder. This study may allow us to define neurovascular safe zones when this approach is used.