Introduction: Posterolateral intertransverse lumbar fusion is a commonly performed procedure for stabilization of the degenerated lumbar spine. A typical clinical scenario for which such fusions are used is the stabilization of a degenerative spondylolisthesis after decompression. In a recent large series reported in the literature, this type of fusion was noted to have a pseudarthrosis rate of up to 45% (Fischgrund, Spine 1997).

Methods: A pilot study was designed to evaluate the safety and efficacy of osteoinductive protein-1 (OP-1, also known as recombinant human BMP-7) in lumbar posterolateral fusion. Thirty-six patients with the diagnosis of symptomatic spinal stenosis and single level degenerative spondylolisthesis in the lower lumbar spine (L3-S1) were enrolled. The patients were randomized to either the OP-1 group or the control group. The OP-1 group received 3.5 mg of OP-1 per side in a putty carrier. The control group received iliac crest autograft alone. Outcomes were measured clinically using the Oswestry score and radiographically using dynamic radiographs evaluated independently by two blinded radiologists using digital calipers. Patients were deemed a clinical success if they showed a > 20% improvement in Oswestry score and were deemed a radiographic success if they showed bridging bone and spinal stability on flexion/ extension films.

Results: At twelve months, 18/21 (85.7%) patients in the OP-1 group and 8/11 (72.7%) patients in the autograft group were considered clinical successes, while 13/18(72.2%) of patients in the OP-1 group and 6/10 (60%) patients in the autograft group were considered radiographic successes. No adverse events related to the use of OP-1 were noted.

Discussion: Despite the non-statistical number of patients enrolled in this pilot study, these preliminary results suggest that OP-1 appears to be a safe and effective replacement for iliac crest autograft in human posterolateral lumbar fusion. The OP-1 group had a higher radiographic fusion rate than the autograft group. This correlated well with the greater clinical success experienced by the OP-1 group, as measured by improvement in the Oswestry score. None of the previously reported device related complications related to the use of BMP’s in animal studies, such as exuberant bone growth with subsequent neural impingement, ectopic ossification, or spinal stenosis, were seen in the treatment group.

Conclusion: OP-1 appears to be a safe and effective replacement for iliac crest autograft in human posterolateral lumbar fusion. The dose, 3.5mg per side, and the carrier, a biodegradable putty, appear to provide a safe and effective means of delivering the bone morphogenetic protein OP-1 to the human lumbar spine.

INTRODUCTION: Posterolateral intertransverse lumbar fusion is a commonly performed procedure for stabilisation of the degenerated lumbar spine. A typical clinical scenario for which such fusions are used is the stabilisation of a degenerative spondylolisthesis after decompression. In a recent large series reported in the literature, this type of fusion was noted to have a pseudarthrosis rate of up to 45% (Fischgrund, Spine 1997).

METHODS: A pilot study was designed to evaluate the safety and efficacy of osteoinductive protein-1 (OP-1, also known as recombinant human BMP-7) in lumbar posterolateral fusion. Thirty-six patients with the diagnosis of symptomatic spinal stenosis and single level degenerative spondylolisthesis in the lower lumbar spine (L3–S1) were enrolled. The patients were randomised to either the OP-1 group or the control group. The OP-1 group received 3.5 mg of OP-1 per side in a putty carrier. The control group received iliac crest autograft alone. Outcomes were measured clinically using the Oswestry score and radiographically using dynamic radiographs evaluated independently by two blinded radiologists using digital calipers. Patients were deemed a clinical success if they showed a > 20% improvement in Oswestry score and were deemed a radiographic success if they showed bridging bone and spinal stability on flexion/ extension films.

RESULTS: At twelve months, 18/21 (85.7%) patients in the OP-1 group and 8/11 (72.7%) patients in the autograft group were considered clinical successes, while 13/18 (72.2%) of patients in the OP-1 group and 6/10 (60%) patients in the autograft group were considered radiographic successes. No adverse events related to the use of OP-1 were noted.

DISCUSSION: Despite the non-statistical number of patients enrolled in this pilot study, these preliminary results suggest that OP-1 appears to be a safe and effective replacement for iliac crest autograft in human pos-terolateral lumbar fusion. The OP-1 group had a higher radiographic fusion rate than the autograft group. This correlated well with the greater clinical success experienced by the OP-1 group, as measured by improvement in the Oswestry score. None of the previously reported device related complications related to the use of BMPs in animal studies, such as exuberant bone growth with subsequent neural impingement, ectopic ossification, or spinal stenosis, was seen in the treatment group.

CONCLUSION: OP-1 appears to be a safe and effective replacement for iliac crest autograft in human posterolateral lumbar fusion. The dose, 3.5 mg per side, and the carrier, a biodegradable putty, appear to provide a safe and effective means of delivering the bone morphogenetic protein OP-1 to the human lumbar spine.

We reviewed two comparable groups of patients who had been treated for lumbar disc herniation by chymopapain chemonucleolysis (145) or conventional surgical discectomy (91). They were reviewed 10 years after treatment by questionnaire, followed by a personal interview by an independent observer. The results of the surgically treated groups were slightly better than those treated with chymopapain. In particular, there was significantly better early relief of leg and low back pain, and fewer patients needed a second procedure. Complications were few in both groups.

Clinical localisation of a disc prolapse required dependable knowledge of the muscles supplied by the lumbosacral nerve roots. Localisation is most difficult in the 10 per cent of patients who have lumbosacral bony segmental anomalies. The lumbosacral plexus has been dissected in 11 cadavers with such anomalies and electrical stimulation studies carried out in 15 patients similarly afflicted. It is suggested that whatever the anomaly the "last fully mobile level" should be identified as the lowest level with a fully formed disc space, bilateral facet joints and two free transverse processes which do not articulate with the sacrum or pelvis. In three out of four patients with bony segmental anomalies the fifth lumbar root emerges at the last fully mobile level.

A prospective study of 480 patients who underwent enzymatic dissolution of the nucleus pulposus with chymopapain is reported. Seventy per cent of patients with the clincial criteria for a disc herniation had a favourable response to chemonucleolysis. The commonest cause of failure was persistent back pain. In patients with sequestered discs or lateral recess stenosis surgical intervention was not made more difficult by chemonucleolysis. Those with a previous operation, spinal stenosis or psychogenic components to the disability had very poor results. Complications were few and easily managed.