Clinical outcome of instrumented fusion for the treatment of failed back surgery syndrome: a case series of 100 patients

OBJECT: Failed back surgery syndrome is defined as persistent chronic low-back pain and/or leg pain lasting more than 1 year, despite of one or more surgical procedures. Instrumented spinal fusion has been offered by surgeons as a potential treatment to recover from pain and functional disability. Factors contributing to good outcome of instrumented spinal fusion have not been investigated extensively. This study evaluated the global perceived recovery and functional status of patients after instrumented fusion for the treatment of failed back surgery syndrome. METHODS: Between January 2004 and September 2007, 100 patients underwent instrumented spinal fusion because of persistent back and/or leg pain lasting more than 1 year despite of one or more previous spine surgeries. The global perceived recovery of the patients was documented on a seven-point Likert scale, in which good outcome was defined as “complete recovery” and “almost complete recovery”. Pain was evaluated by the 100-mm visual analogue scale (VAS) of back pain and leg pain, and functional disability measured by the Roland Disability Questionnaire for Sciatica (RDQ) and Oswestry Disability Index (ODI). The Hospital Anxiety and Depression Scale (HADS) evaluated psychological co-morbidity. All patients were sent questionnaires by mail. Pearson’s correlation coefficient was calculated between outcome measures and preoperative patient characteristics. RESULTS: Eighty-two patients (82% response rate) returned questionnaires that were useful for analysis. After a mean follow-up period of 15 months, 35% of the patients reported good outcome, whereas 65% had unsatisfactory outcome. The mean (± SD) score of VAS low-back pain and leg pain was 45.7 ± 29 and 37.9 ± 31.9, respectively. The mean (± SD) RDQ and ODI score was 11.8 ± 5.4 and 30.6 ± 20.3, respectively. HADS score indicated a possible anxiety disorder in 28% of the patients and in 30% a possible underlying depression. Of the patients’ baseline characteristics, there was only a significantly negative correlation between level of education and outcome. CONCLUSIONS: The present study showed disappointing outcome of instrumented fusion for the treatment of failed back surgery syndrome in terms of perceived recovery, functional disability and pain. Conservative management is probably more beneficial and, therefore, more selective and careful assessment should be done in order to prevent unnecessary surgery.