Posterior cervical fusion failure in three morbidly obese patients following circumferential surgery

The stability of multilevel anterior corpectomy with fusion (ACF) is often enhanced by simultaneous posterior fusion (PF) which provides a "posterior tension band." Three morbidly obese patients undergoing circumferential surgery had posterior fusions performed without autogenous iliac crest graft to avoid donor site morbidity.

Three morbidly obese patients (300-350 lbs.), averaging 48 years of age, presented with rapidly progressive moderate/severe myelopathies. Magnetic resonance imaging (MRI) and computed tomography (CT) studies demonstrated severe ventral ossification of the posterior longitudinal ligament. Two to four level plated ACFs were performed utilizing fibula strut allograft and plates. Posterior spinous process wiring/fusion from C2-T1 were completed with braided titanium cables, fibula strut allografts, Inductive Conductive Matrix (a form of demineralized bone matrix), and allograft bone to avoid iliac crest donor site morbidity in such morbidly obese patients. Halo devices were utilized until fusion was documented on postoperative X-ray and 2D-CT studies subsequently obtained 3, 6, and up to 12 months postoperatively. Patients were followed an average of 3 years.

Postoperatively, all 3 patients demonstrated mild residual myelopathy (Nurick Grade 0-I). Nevertheless, all 3 exhibited posterior pseudarthroses accompanied by anterior strut/plate extrusion (1 patient), partial anterior graft pseudarthrosis (1 patient), and a delayed strut fracture (1 patient). The first 2 patients required secondary posterior fusions performed with autogenous iliac crest graft, while the third fused with 6 months of additional bracing.

Following circumferential cervical procedures, posterior fusions failed in 3 morbidly obese patients where iliac crest autograft was omitted in an attempt to avoid donor site morbidity.