An Anatomic Study of Inferior Glenohumeral Recess Portals: Comparative Anatomy at Risk

Abstract

The purpose of this study was to describe the musculotendinous relations and neurologic structures at risk during establishment of posterior portals for access to the inferior glenohumeral recess (IGHR). Three 18-gauge spinal needles were used to establish 2 posteroinferior portals and 1 axillary pouch portal in 14 embalmed cadaveric shoulders, without joint distention and arthroscopic visualization. At dissection, musculotendinous structures traversed by the needles were recorded, and distances from the (1) axillary nerve (at the deltoid undersurface, quadrangular space, and capsule), (2) nerve to teres minor (at the inferior border of the teres minor muscle and at the capsule), and (3) suprascapular nerve were measured. Additional parameters studied included the vertical distances between the acromion and IGHR and between the acromion and axillary nerve. Statistical analysis (multiple comparisons procedure) was performed to compare relative portal safety. The mean distance of the axillary pouch portal to the 3 nerves, at each level, was greater than that of the posteroinferior portals. In 1 specimen (7.1%), the posteroinferior portal tracts were in close proximity (within 2 mm) to the axillary nerve and its branch to the teres minor. The distance of the axillary pouch portal to the nerves was significantly greater (P < .05) at every level, except at the deltoid undersurface. Our study suggests that posterior portal techniques described for access to the IGHR are safe; the risk of axillary nerve injury with posteroinferior portals is low, though possible. The axillary pouch portal is relatively farther away from the neurologic structures and provides safer access to the same region. Arthroscopic procedures that require access to the IGHR can be safely performed with posteroinferior and axillary pouch portals. The axillary pouch portal may be used preferentially for this access because it is placed farthest from the neurologic structures.