Purpose of study: The aim of this study was to evaluate patient-orientated outcome of spinal dynesys fixation used for low back pain and also the re-operation rate in a retrospective review of 25 cases with an average follow-up period of four years.

Materials and Methods: A total of 25 patients who had undergone semi-rigid fixation of the lumbar spine with the Dynesys system in the Chase Farm Spinal Unit between November 2001 and March 2003 were reviewed.

Results: Two patients required removal of implant and revision to solid fusion. Both were one year post Dynesys instrumentation. All other patients had their original Dynesys implant in situ at latest follow-up. Two patients were referred to a pain specialist for further management. The mean Oswestry score pre-operatively and 4.4 year post operatively were 57.2 and 37.52 respectively. The mean VAS pre op was 9.32 and post op it was 5.04.

Conclusion: Dynamic stabilisation certainly continues to remain an attractive alternative to rigid stabilisation and the few retrospective and laboratory studies that exist in the current literature reveal results which are comparable with rigid fixation.

Discussion: Though te results were promising we think a large multicentre prospective studies are required to truly enable us to evaluate the efficacy of dynamic stabilisation. This study contributes towards furthering our understanding of this complex subject.

Ethics approval: None

Interest Statement: None

Objective scoring techniques for back pain are increasingly being used both in the pre-operative selection of patients and as a post-operative outcome measure. Our aim was to determine the strength of correlation between three main scoring techniques used to quantify the severity of the back or leg pain on presentation to a chronic back pain clinic.

The Oswestry Disability Index (ODI), the Medical Outcomes Study 36 item Short Form Health Survey (SF36), and the Visual Analogue Scale (VAS) were competed by 130 patients between July and December 1999. There were 65 males and 65 females with the mean age of 49 years. The patients were divided into three groups: with back pain only, sciatic leg pain only, and those with both. The correlation was analysed using the Pearson correlation test.

There was a good correlation between the Oswestry Disability Index and Visual Analogue Scale for patients with back pain (r=0.641, p< 0.001) and with sciatic leg pain (r=0.469, p< .001). The physical component of the SF36 strongly correlates with the VAS in back pain (r=0.364) and sciatic leg pain (r=1). However there is a poor correlation between the ODI and VAS and all other components of the SF36.

We report a high rate of failure of the Ring polyethylene cementless cup caused largely by granulomatous osteolysis. We have reviewed 126 prostheses inserted from 1986 to 1992 at from 11 to 90 months after surgery. There was radiological evidence of osteolytic granulomas adjacent to the external surface of the cup in 32%, appearing on average at three years from operation. In a subgroup of 59 prostheses followed for at least four years the incidence of such changes was 54%. A total of 27 cups (22%) have required revision, 21 for granulomatous loosening at an average follow-up of five years. In the retrieved prostheses there was obvious polyethylene abrasion and histological examination confirmed the presence of polyethylene wear debris. We found no significant correlation of osteolysis with cup size, although smaller cups were predominant among those having revision.