The use of osteotech surface-activated cortical lordotic allograft in anterior cervical discectomy and fusion

The Osteotech Osteo Active cortical lordotic spacer is an allograft interbody graft that is surface demineralized to a standard depth to allow exposure of growth factors. The availability of growth factors on the surface of the allograft purportedly creates a biologically active surface capable of stimulating bone growth while preserving implant strength without adding any additional bone graft or osteoinductive agents (including demineralized bone matrix). However, no scientific articles exist demonstrating the fusion rate in anterior cervical discectomy and fusion (ACDF) procedures using this allograft. This study is a prospective, cohort study with 38 consecutive patients who underwent ACDF with Osteotech surface demineralized cortical, lordotic allograft, and anterior cervical plating via modified Smith-Robinson technique. Radiographic fusion was determined with plain radiographs and complications were assessed. Average follow-up was 29.6 months, with a minimum of 2-year follow-up (range, 24 to 46 mo). The average age was 51.3 years (range, 32 to 68 y) and the comorbidities included 13 smokers, I diabetic, and 8 patients with prior surgeries. Three frank nonunions with radiolucent lines and/or motion on flexion/extension radiographs were noted, and 3 additional levels were suspicious for delayed union with evidence of incomplete incorporation. The fusion rate was 92.3% (72/78) of levels.. including three 3-level fusions that had not gone to arthrodesis. Four out of 6 patients with nonunions or delayed unions were smokers. There was no evidence of graft fracture even in the face of surface treatment of the allograft with the demineralization process. Two patients who underwent revision ACDF for previous pseudarthrosis fused with the revision procedure using the Osteotech cortical allograft. There were no instances of hardware failure or reoperation for graft failure, pseudarthrosis. or nonunion. Two patients had plate subsidence with encroachment of the hardware on the adjacent level. Complications occurred in 3 patients (7.9%) with 2 urgent irrigation and debridements for evacuation of postoperative seroma/hematoma and I patient with significant dysphagia and dysphonia. The fusion rate and lack of reoperations in this prospective cohort study establishes that the surface activated allograft used in this study is an excellent interbody device. The surface activation of the cortical allograft allows incorporation in the anterior cervical interspace without additional demineralized bone graft or autograft. Future studies could elucidate if the rate of fusion may be hastened by the surface-activated graft due to the exposed demineralized bone matrix and resultant osteoinductivity.