Type II: Most common fracture subtype; greater than 3 mm translation, and greater than than 10 deg angulation; these frx are apparently caused by hyperflexion and are unstable; frx is manifested by pars frx, anterior displacement of C2 body, & disruption & asymmetric widening of C2-3 disc space as well as soft tissue swelling; C2-3 disk and posterior longitudinal ligament are disrupted; anterior longitudinal ligament usually remains intact; type II is typically rx'ed w/ halo vest for 3 months; type II injuries may be difficult to manage; following reduction, halovest trial is reasonable, but this device may not maintain alignment.

Type IIa: Flexion/distraction variant, unstable; fracture line is more oblique than vertical and there is more angulation vs translation; posterior C2-3 disc space widening (more w/ traction); type IIA, in addition to frx of type II, has widening of posterior part of C2-3 disk w/ traction, & should be rx'ed in halovest; this is also rx'ed w/ halo vest, but avoid overdistraction; halo traction may cause overdistraction of this frx;traction may cause further fracture displacement and is avoided.