Object The authors report the results of a prospective randomized multicenter study in which the results of cervical disc arthroplasty were compared with anterior cervical discectomy and fusion (ACDF) in patients treated for symptomatic single-level cervical degenerative disc disease (DDD). Methods Five hundred forty-one patients with single-level cervical DDD and radiculopathy were enrolled at 32 sites and randomly assigned to one of two treatment groups: 276 patients in the investigational group underwent anterior cervical discectomy and decompression and arthroplasty with the PRESTIGE ST Cervical Disc System (Medtronic Sofamor Danek); 265 patients in the control group underwent decompressive ACDF. Eighty percent of the arthroplasty-treated patients (223 of 276) and 75% of the control patients (198 of 265) completed clinical and radiographic follow-up examinations at routine intervals for 2 years after surgery. Analysis of all currently available postoperative 12- and 24-month data indicated a two-point greater improvement in the neck disability index score in the investigational group than the control group. The arthroplasty group also had a statistically significant higher rate of neurological success (p = 0.005) as well as a lower rate of secondary revision surgeries (p = 0.0277) and supplemental fixation (p = 0.0031). The mean improvement in the 36-Item Short Form Health Survey Physical Component Summary scores was greater in the investigational group at 12 and 24 months, as was relief of neck pain. The patients in the investigational group returned to work 16 days sooner than those in the control group, and the rate of adjacent-segment reoperation was significantly lower in the investigational group as well (p = 0.0492, log-rank test). The cervical disc implant maintained segmental sagittal angular motion averaging more than 7°. In the investigational group, there were no cases of implant failure or migration. Conclusions The PRESTIGE ST Cervical Disc System maintained physiological segmental motion at 24 months after implantation and was associated with improved neurological success, improved clinical outcomes, and a reduced rate of secondary surgeries compared with ACDF.

In a multicenter, prospective, randomized, nonblinded, 2-year study, 279 patients with degenerative lumbar disc disease were randomly divided into two groups that underwent interbody fusion using two tapered threaded fusion cages. The investigational group (143 patients) received rhBMP-2 on an absorbable collagen sponge, and a control group (136 patients) received autogenous iliac crest bone graft. Plain radiographs and computed tomographic scans were used to evaluate fusion at 6, 12, and 24 months after surgery. Mean operative time (1.6 hours) and blood loss (109.8 mL) were less in the investigational rhBMP-2 group than in the autograft control group (2.0 hours and 153.1 mL). At 24 months the investigational group's fusion rate (94.5%) remained higher than that of the control group (88.7%). New bone formation occurred in all investigational patients. At all intervals, mean postoperative Oswestry, back pain, and leg pain scores and neurologic status improved in both treatment groups with similar outcomes. In the control group, eight adverse events related to the iliac crest graft harvest occurred (5.9%), and at 24 months 32% of patients reported graft site discomfort and 16% were bothered by its appearance. Lumbar fusion using rhBMP-2 and a tapered titanium fusion cage can yield a solid union and eliminate the need for harvesting iliac crest bone graft.

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Multicenter human clinical studies of patients undergoing anterior lumbar fusion have been conducted using recombinant bone morphogenetic protein or rhBMP-2 on an absorbable collagen sponge, marketed as INFUSE Bone Graft, or autograft implanted in the LT-CAGE Lumbar Tapered Fusion device. An integrated analysis of multiple clinical studies was performed using an analysis of covariance to adjust for preoperative variables in a total of 679 patients. Of these patients, 277 had their cages implanted with rhBMP-2 on an absorbable collagen sponge and 402 received autograft transferred from the iliac crest. The patients treated with rhBMP-2 had statistically superior outcomes with regard to length of surgery, blood loss, hospital stay, reoperation rate, median time to return to work, and fusion rates at 6, 12, and 24 months. Oswestry Disability Index scores and the Physical Component Scores and Pain Index of the SF-36 scale at 3, 6, 12, and 24 months showed statistically superior outcomes in the rhBMP-2 group.