Spondylolytic spondylolisthesis is one of the common causes of mechanical low back pain in adults. Conservative treatment of such cases, particularly for the low grade slips, remains the mainstay of management. When patients’ symptoms are marked and not responsive to conservative therapy, the surgical option can be considered. Up to the time of writing this abstract [January 2003], arthrodesis of the affected motion segment with or without instrumentation is the standard surgical option for treating mechanical low back pain. Results of different types of arthrodesis for treating such condition had been reported in literature, including posterior fusion, posterolateral fusion, and posterior and anterior interbody fusion.

Between 1993 and 1998, seventy- five adult patients with grade I or II lytic spondylolisthesis were treated by in situ posterolateral fusion and segmental instrumentation using the Oswestry Pedicle Screw System, with or without extended Gill’s procedure. The indications for surgical intervention in these cases were significant reduction in the quality of life with persistent low back pain and/or leg pain after a minimum of six months conservative therapy. Confirmatory imaging studies consistent with the clinical data should also be obtained before deciding the surgical option. The average operative time was 2.5 hours [range 2–4 hours). The average blood loss was 850 mls (range 300–2300 mls)

After an average follow-up of 60.7 months (range 24–95 months) clinical results were excellent and good in 92%, and radiological union was achieved in 94% of patients. Complications included 2 cases with superficial wound infection, one case with deep wound infection, and four of the patients went to non-union.

In conclusion, with a careful patient selection, patients with instrumental insitu posterolateral fusion gained a satisfactory clinical and radiological outcome and the results were maintained for an adequate postoperative period.

Objectives: To evaluate the clinical and radiological outcome following anterior interbody fusion using a femoral cortical allograft packed in the centre with autogenous iliac graft combined with posterior pedicle fixation.

Design: A prospective study of 30 consecutive adult patients diagnosed with lumbar degenerative disc disease.

Summary of background data: Various fusion options have been described in the literature with various clinical and radiological outcomes. Narrowing of the disc space is thought to be the primary cause of all the potential secondary spondylotic changes; the ideal corrective surgery would be one that reconstitutes the disc space interval. A hybrid graft consisting of a femoral cortical allograft (FCA) ring packed in the centre with autogenous cancellous iliac graft seems to be an ideal option as one should capitalize on the mechanical strength of the cortical ring and the biological strength of the cancellous autogenous graft.

Methods: 15 patients with failed back surgery, 15 patients with primary degenerative disc disease. Mean age was 43 years. All patients had preoperative radiographs, MRI scanning, discography was not used in this study. All femoral allografts were processed by freeze drying and sterilized using ethylene oxide. The protocol for surgery consisted of:

* Left sided retroperitoneal muscle splitting approach

Results: There were no complications from using the allograft. Intraoperative and postoperative complications were seen in 3 patients. After a minimum follow up of 2 years good clinical outcome was achieved in 83 % using Ricciardi et al criteria, solid fusion was achieved in 98%.

Conclusion: The results in this study continue to support the efficacy of using hybrid interbody grafts to achieve a successful fusion, however there is discrepancy between the radiological and clinical outcome which merits additional investigations