110 - Comparison of RhBMP-2 with Allograft in Single-level Anterior Cervical...

#110 Comparison of RhBMP-2 with Allograft in Single-level Anterior Cervical Arthrodesis

Cervical Therapies and Outcomes

Poster Presented by: J.K. Burkus

Author(s):

J.K. Burkus (1)
R.F. Dryer (2)
P.M. Arnold (3)

(1) The Hughston Clinic, Columbus, GA, United States
(2) Central Texas Spine Institute, Austin, TX, United States
(3) University of Kansas Medical Center, Department of Neurosurgery, Kansas City, KS, United States

Abstract

Purpose: To determine the efficacy of rhBMP-2 in inducing fusion and improving arm pain and function in patients undergoing anterior cervical discectomy and fusion (ACDF) for single-level cervical degenerative disc disease, we compared ACDF using rhBMP-2 with a PEEK implant and plate with ACDF using allograft and plate in 710 patients with symptomatic single-level cervical degenerative disc disease in a prospective, multicenter, historically controlled trial.

Methods: Two hundred twenty-four patients were enrolled in a prospective Investigational Device Exemption clinical trial to evaluate rhBMP-2/ACS in ACDF (0.6 mg in 240 patients, 1.05 mg in 4 patients). Clinical outcomes in rhBMP-2 patients were compared with those in 486 historical control patients treated with allograft spacer and cervical plate from 2 contemporary IDE trials. A propensity score technique was used to minimize potential biases for the comparisons between these treatment groups. Assessments were completed preoperatively, at discharge, and during follow-up visits at 1.5, 3, 6, 12, and 24 months. Adverse events were recorded at every visit.

Results: At 24 months, mean Neck Disability Index score improvement was greater in the rhBMP-2 group (37.1 points) than in the allograft group (31.4 points, p=0.002). Mean arm pain improvement was 11.0 points in the rhBMP-2 group compared with 9.7 points in the allograft group (p=0.031). The overall neurological success rate was significantly higher in the rhBMP-2 group (p< 0.001). Neck pain and general health status (SF-36 PCS and MCS) were similar for both groups. The fusion rate in the rhBMP-2 group was 99.4% as determined by an independent radiology group. On reassessment of the allograft control patients, this same group found a fusion rate of 87.2% in contrast to the original fusion rate of 96%, which was assessed by a different radiology group.

Cumulative adverse event rates were similar in the two groups, and no statistical or clinical differences in serious adverse event rates were observed. However, higher rates of some early adverse events--dysphagia, local swelling, and neck pain--were observed in the rhBMP-2 group. Additionally, through 24 months, the rate of subjects with any heterotopic ossification, all located in the anterior region away from the spinal canal, was significantly higher in the rhBMP-2 group (p< 0.001).

Conclusions: RhBMP-2 was effective in inducing fusion and improving arm pain and function in patients undergoing ACDF for single-level cervical degenerative disc disease. Higher rates of certain adverse events and heterotopic ossification were observed in the rhBMP-2 group.