Multilevel anterior cervical fusion using a collagen-hydroxyapatite matrix with iliac crest bone marrow aspirate: an 18-month follow-up study

The pseudarthrosis rate after multisegment anterior cervical fusion is directly related to the number of levels surgically fused. The advent of osteobiological adjuvants offers an opportunity to reduce both the likelihood of failed arthrodesis and the need for posterior instrumentation. Collagen-hydroxyapatite matrix is osteoconductive and has been used with autogenous bone marrow aspirate (BMA) to promote fusion. We report our results of using collagen-hydroxyapatite matrix with BMA for multilevel anterior cervical discectomy and fusion and anterior cervical corpectomy and fusion (ACCF). Sixty-six consecutively treated patients underwent a multilevel anterior cervical discectomy and fusion and/or ACCF during a period of 16 months. In all cases, a Smith-Robinson decompression was performed followed by allograft fibula strut grafting filled with collagen-hydroxyapatite matrix and BMA, and anterior semiconstrained cervical plating. A vacuum chamber was used to draw the BMA slowly through the collagen-hydroxyapatite sponges. No patient underwent simultaneous posterior instrumentation. Clinical outcome was determined by an independent observer who evaluated patients on the basis of symptom and neurological examination results. Radiographic fusion was determined by dynamic x-rays and computed tomographic scanning during an 18-month follow-up period. With the inclusion of discectomies performed in ACCF procedures, patients were fused between two and five disc levels (mean, 3.1 levels). Seventeen patients underwent one to four-level corpectomies (mean, two levels). Clinical improvement was observed in 49 patients. Conditions in nine patients remained unchanged, and two patients had radicular palsies. In all, 60 patients were followed and analyzed for radiographic fusion. All but two patients demonstrated successful radiographic fusion. Collagen-hydroxyapatite matrix with BMA can be a safe, effective adjuvant for promoting fusion in multilevel anterior cervical discectomy and fusion and ACCF. Although randomized, controlled studies are necessary to determine whether or not the fusion rates are superior to those obtained from using allograft alone, these results compare favorably to historical data in the literature.