Background: The Wallis Interspinous implant was developed as a minimally invasive and anatomically conserving procedure without recourse to rigid fusion procedures. The initial finite element analysis and cadaver biomechanical studies showed that the Wallis ligament improves stability in the degenerate lumbar motion segment. Unloading the disc and facet joints reduces intradiscal pressures at same and adjacent levels allowing for the potential of the disc to repair itself.

Aims & Methods: The purpose of this prospective study is to demonstrate the survivorship and clinical effectiveness of Wallis implant against low back pain and functional disability in patients with degenerative lumbar spine disease. Patients were assessed pre operatively and post operatively every 6 months by VAS pain score, Oswestry Disability Index, SF-36. All the patients had pre operative radiographs, MRI scans and followed up with interval radiographs. The results were assessed in three sub groups. Group-1 is decompression and stabilisation, group-2 is stabilisation alone, and group- 3 is “Topping off” a fusion.

Results: A total of 211 Wallis Ligaments were inserted in 203 patients between July 2003 and November 2006. In total 179 patients were reviewed with mean age of 54(24–85) were followed for an average 30 months (6–40). The most common level is L4/5 (59%) followed by L3/4. In all the subgroups pain scores and oswestry disability index improved by 50%. And similarly SF-36 scores improved. There is 75–80% good clinical outcome with a survivorship of 98–99%.

Low infection rate of 1.1%. Two cases of prolapsed discs at the same level requiring further discectomy and one case of iatrogenic L4 paraesthesia.

Conclusions: The Wallis ligament represents a successful non fusion alternative in treatment of degenerative lumbar spine disease with least soft tissue damage, quick rehabilitation, less morbidity and associated low complication rate.

The Wallis implant treats pain, preserves mobility, anatomy and stability while being fully reversible, therefore leaving all subsequent options open.

Background: The major problem achieving lumbar spinal fusion is developing pseudarthrosis. At present the gold standard in achieving fusion is the use of autograft from pelvis or posterior elements of the spine. However the potential limitations of insuffient quantity and donor site morbidity have led to search for bone graft alternatives like DBM which contains osteinductive BMPs.

Aims & Methods: A Prospective Randomized Control trial comparing the effectiveness of demineralised Bone Matrix (DBM Putty)/autograft composite with autograft in lumbar spinal fusion.

35 patients were included in the trial; they were randomized to have DBM and autograft on one side, and autograft alone on other side to side. Patients were followed up with interval radiographs for total of 24mons. To date 20 patients have completed minimum 12mons follow up. The mineralization of fusion mass lateral to the instrumentation on each side was graded Absent, Mild (< 50%), Moderate (> 50%) or Complete fusion (100%). The assessment was made by two orthopaedic consultants and a musculoskeletal radiologist who were blinded to graft assignment.

Results: The sex distribution was 11:9 male to females with a mean age of 55.2 (21–87 years) and an average follow up of 18mons (12–24mons). Nine patients had single level fusion and the remainder had more than one level fusion. At 12 months on the side of DBM, 15% (6 of 20) had complete fusion, 80% (16 of 20) had moderate fusion, and 5% had no fusion mass. During the same period on the other side, 25% did not show any sign of fusion. There was no correlation with number of levels, age or sex.

Conclusions: Osteoinductive properties of DBM would appear to help in achieving early and higher union rates in lumbar spinal fusion. DBM reduces the amount of harvested autograft graft and also minimises the morbidity of donor site complications.