BY LAUREN UZDIENSKI, JULY 22, 2009
This month JBJS published a review entitled “What’s New in Spine Surgery.” We’ve summarized some of the highlights below.
Positive Outcomes for Cervical Disc Arthroplasty
- In two recent studies, arthroplasty was associated with equal or greater pain relief and functional outcomes when compared to fusion and discectomy. Adverse events were similar in both groups, with fewer reoperations in the arthroplasty group. Satisfactory outcomes were maintained at four years in both the arthroplasty and fusion groups.
Biologics Show Promise, But Development is Slow
- BMPs: Results have been “inconsistent” in studies of DePuy’s GDF-5. BMP-7 (Stryker’s OP-1) is reportedly still under review by the FDA, and it has been suggested that the current concentration of the BMP may be insufficient for spinal fusion. BMP-2 (Medtronic’s Infuse) has performed well in studies, but concerns remain about adverse events, particularly in the cervical spine.
- Bone graft substitutes: Mesenchymal stem cells remain an area of interest, though the amount of cells needed to elicit a bone-healing response as well as what triggers need to be expressed by the cells is unknown.
- Disc degeneration: biologic treatments in this space are developing at a “slow pace,” though a human trial evaluating BMP delivery to discs to prevent degeneration is in development.
New Technologies, New Patients for Lumbar Spine Procedures
- SPORT: Compared to nonsurgical treatment, surgical treatment resulted in better outcomes for all patients in the study. Compared to patients with primary back pain, patients with primary leg pain improved more with surgical treatment.
- Surgery in the elderly: Higher complication rates are observed in this population, though one recent study demonstrated the “substantial benefits” associated with fusion in this group.
- New technology: In one study comparing Zimmer’s Dynesys, a pedicle-based dynamic stabilization system, with lumbar posterolateral fusion, the dynamic stabilization group reported a greater improvement in leg pain and back pain scores when compared to fusion, though overall results in both groups were comparable. A separate study evaluating Dynesys found that 20% of patients receiving the device required re-operation at two years. 39% of these cases were attributable to screw loosening, with additional complications including screw breakage and cephalad spinal stenosis.
