Purpose of the Study: To ascertain the role of Dynesys system (Zimmer Spine, Minneapolis) in the surgical management of chronic low back pain

Methods: 55 patients with persistent low back pain despite conservative measures were treated with Dynesys over a period of two and a half years. Participants either underwent Dynesys procedure alone or in combination with fusion or decompression surgery. Oswestry Disability Index (ODI), Visual Analogue Scores (VAS) and SF-36 questionnaires were completed pre-operatively and at one and two years post-operatively. Pre-operative testing using the Distress and Risk Assessment Method (DRAM) identified psychological distress prior to surgery. Patient Oriented Outcome questionnaires were circulated retrospectively following surgery to obtain data regarding patient’s perceptions and expectations of their outcome.

Results: Overall, the mean ODI reduced by 10.23% after one year and 16.15% after two years following surgery. VAS improved by 12mm one year and by 17mm two years after operation. Patients with psychological distress pre-operatively showed less improvement in their ODI and VAS at two-year follow up. The results of fusion were similar to Dynesys alone, and patients who also had decompression had best results. 72.2% patients reported an improvement following their surgery and the same percentage would have the operation again in retrospect.

Conclusion: This is the first study exploring clinical outcomes following surgery using Dynesys dynamic stabilization system in patients with disabling low back pain. Previous studies have reported good outcome in the treatment of spinal stenosis. Over 70% patients in our study reported improvement following the procedure but more evidence is needed to determine if it is a viable alternative to spinal fusion.

The operative and anaesthesic technique for 44 patients undergoing posterior spinal fusion with Harrington rod instrumentation for idiopathic scoliosis is described. There were two groups of 21 and 23 patients, matched for diagnosis and status before operation. The management of both groups was similar but in one group anaesthesia with induced hypotension was employed, using a mixture of sodium nitroprusside and trimetaphan. The mean blood loss at operation and after operation in this group was significantly lower than in the other group, with a consequent reduction in the transfusion requirement. No adverse sequelae were observed. All patients showed a drop in haemoglobin concentration after operation, despite clinically adequate blood transfusion.