Posterior lumbar interbody fusion is a well-described procedure for the treatment of back pain associated with degenerative disc disease and segmental instability. It allows decompression of the spinal canal and circumferential fusion through one posterior incision. The aim of this study is to assess fusion rate as well as long term outcome of this procedure.

Methods: Fifty-six consecutive patients who underwent posterior lumbar interbody fusion (PLIF) using carbon cages and pedicle fixation between 1993 and 2000 were recruited and contacted with postal survey. Clinical outcome was measured using changes in Oswestry Disability Index (before the surgery and at the time of the study) and patient questionnaire containing pain improvement, analgesic use, return to work and satisfaction with surgical outcome.

Fusion rate was assessed using standard X-rays with scoring system described by Brantigan and Steffee.

Results: The average age of the patients at the time of surgery was 43 years. The complication involved one misplaced pedicle screw, one dural tear, one deep infection, one displacement of the cage and one pulmonary embolism. The mean postoperative duration at the time of the study was 4.4 years. The response rate to the survey was 84%. Overall radiological fusion rate was 94%. There was a significant improvement in Oswestry Disability Index P< 0.001. Eighty five percent of the patients were satisfied with their surgical outcome and fifty eight percent of the work eligible patients had resumed their pre-disease activity level and full employment.

Conclusions: The combination of posterior lumbar inter-body fusion (PLIF) with posterolateral instrumented fusion is a safe and effective method of achieving circumferential segmental fusion. This procedure gives sustained long-term improvement in functional outcome and high satisfaction rate.