rhBMP-2 (Recombinant Human Bone Morphogenetic Protein-2) in real world spine surgery. A phase IV, National, multicentre, retrospective study collecting data from patient medical files in French spinal centres.

BACKGROUND: This is a Phase IV, national, multicentre, retrospective study to observe the real-world use of rhBMP-2 in France. HYPOTHESIS: There was no statistical hypothesis, the statistical analyses were descriptive in nature. PATIENTS AND METHODS: Data was collected from patient medical files in 10 French spinal centres. Primary objectives were to understand which patients were treated with rhBMP-2, commercialised in Europe as InductOs™ and how rhBMP-2 was used during spinal fusion surgery in France between 2011 and 2012. RESULTS: Four hundred patients (634 levels) treated with rhBMP-2 were included in the analysis. The most frequent primary diagnostic indication for rhBMP-2 use was degenerative disc disease (DDD; 129/400; 32.3% of patients) followed by spondylolisthesis (119/400; 29.8%), deformity (59/400; 14.8%) and pseudoarthrosis (29/400; 7.3%). The most frequently treated level was L4-L5 (33.8% of levels in 53.5% of patients); followed by L5-S1 (29.8%, 47.3%), L3-L4 (16.7%, 26.5%), and L2-L3 (7.3%, 11.5%), all other levels (less than 5% of patients). No interbody fusion device was used in 42.7% of levels. Wetted matrix of rhBMP-2 was placed in the interbody space in 58.4% of levels (370/634). The most common procedure for rhBMP-2 treatment was posterior lumbar fusion (PLF) (221/634; 34.9% of levels), followed by anterior lumbar interbody fusion (ALIF) (188/634; 29.7%), posterior lumbar interbody fusion (PLIF) (111/634; 17.5%), lateral lumbar interbody fusion (LLIF) (106/634; 16.7%), transforaminal lumbar interbody fusion (TLIF) (4/634; 0.6%) and 'other' (4/634; 0.6%). Thirty-one adverse events of Interest (AEI) were recorded in 27 patients. One AEI was considered related to rhBMP-2. Unplanned secondary spine interventions at index level treated with rhBMP-2 were required in 4 patients. DISCUSSION: In years 2011 and 2012 when the surgeries captured in this retrospective study were done, rhBMP-2 was indicated for single level (L4-S1) anterior lumbar spine fusion as a substitute for autogenous bone graft in adults with DDD. The most common procedure for the treatment with rhBMP-2 was PLF (off-label use), followed by ALIF (on-label use). The safety findings confirm a predictable and manageable safety profile. LEVEL OF EVIDENCE: IV.

Posterior dynamic stabilization systems: DYNESYS.

Posterior dynamic stabilization systems have to neutralize injurious forces and restore painless function of the spine segments and protect the adjacent segments. Because degenerative disc disease has many clinical manifestations, pedicular screw systems and interspinous implants have their indications. A dynamic stabilization device has to provide stability throughout its lifetime, unless it activates or allows reparative processes with a reversal of the degenerative changes. Anchorage to the bone is crucial, at least for pedicular systems. This is a great demand on spinal implants and assumes rest and motion going together. Our experience with DYNESYS has shown that this method has limitations in elderly patients with osteoporotic bone or in patients with a severe segmental macro-instability combined with degenerative olisthesis and advanced disc degeneration. Such cases have an increased risk of failure. Only future randomized evaluations will be able to address the potential reduction of accelerated adjacent segment degeneration. The few posterior dynamic stabilization systems that have had clinical applications so far have produced clinical outcomes comparable with fusion. No severe adverse events caused by these implants have been reported. Long-term follow-up data and controlled prospective randomized studies are not available for most of the cited implants but are essential to prove the safety, efficacy, appropriateness, and economic viability of these methods.

The dynamic neutralization system for the spine: a multi-center study of a novel non-fusion system.

Various forms of lumbar instability require a surgical stabilization. As an alternative to fusion, a mobile, dynamic stabilization restricting segmental motion would be advantageous in various indications, allowing greater physiological function and reducing the inherent disadvantages of rigid instrumentation and fusion. The dynamic neutralization system for the spine (Dynesys) is a pedicle screw system for mobile stabilization, consisting of titanium alloy screws connected by an elastic synthetic compound, controlling motion in any plane (non-fusion system). This prospective, multi-center study evaluated the safety and efficacy of Dynesys in the treatment of lumbar instability conditions, evaluating pre- and post-operative pain, function, and radiological data on a consecutive series of 83 patients. Indications consisted of unstable segmental conditions, mainly combined with spinal stenosis (60.2%) and with degenerative discopathy (24.1%), in some cases with disc herniation (8.4%), and with revision surgery (6.0%). Thirty-nine patients additionally had degenerative spondylolisthesis, and 30 patients had undergone previous lumbar surgery. In 56 patients instrumentation was combined with direct decompression. The mean age at operation was 58.2 (range 26.8-85.3) years; the mean follow-up time was 38.1 months (range 11.2-79.1 months). There were nine complications unrelated to the implant, and one due to a screw malplacement. Four of them required an early surgical reintervention. Additional lumbar surgery in the follow-up period included: implant removal and conversion into spinal fusion with rigid instrumentation for persisting pain in three cases, laminectomy of an index segment in one case and screw removal due to loosening in one case. In seven cases, radiological signs of screw loosening were observed. In seven cases, adjacent segment degeneration necessitated further surgery. Mean pain and function scores improved significantly from baseline to follow-up, as follows: back pain scale from 7.4 to 3.1, leg pain scale from 6.9 to 2.4, and Oswestry Disability Index from 55.4% to 22.9%. These study results compare well with those obtained by conventional procedures; in addition to which, mobile stabilization is less invasive than fusion. Long-term screw fixation is dependent on correct screw dimension and proper screw positioning. The natural course of polysegmental disease in some cases necessitates further surgery as the disease progresses. Dynamic neutralization proved to be a safe and effective alternative in the treatment of unstable lumbar conditions.