Radiological and functional outcome after anterior lumbar interbody spinal fusion

Outcome after anterior spinal fusion has mainly been studied radiologically and reported fusion rates vary greatly. The aim of this study was to investigate radiological and long-term clinical outcome. The study comprised 120 consecutive patients, operated on during the period 1979-1987, with single-or two-level anterior interbody spinal fusion due to disc degeneration or isthmic spondylolisthesis with lumbar instability. In 64 patients a supplemental facet joint fusion was performed. Clinical outcome was evaluated 5-13 years after surgery using the patient-administered Dallas Pain Questionnaire (DPQ). Radiological outcome was determined on the basis of radiographs taken at a 2-year follow-up assessed by independent observers. The radiological follow-up rate was 98%. Complete fusion was found in 52%, questionable fusion in 24%, and definitive pseudoarthrosis in 24% of patients. Radiological results were poor in patients who had undergone previous spinal surgery (P < 0.05) and in those with two-level fusion (P < 0.05). The DPQ reply rate was 80%. Sixty-six patients claimed improvement in all functional groups. Patients with complete or questionable union had significantly better results than did those with non-union (P < 0.01). Poorer functional outcome was found in patients who had undergone previous spinal surgery (P < 0.01) or fusion at the L4/L5 level (P < 0.05), in those who had responded poorly to the preoperative test brace (P < 0.05), and in those above 45 years old at the time of surgery (P < 0.05). Radiological and functional outcome did not vary according to whether patients were treated postoperatively with a plaster jacket or with facet screw fixation. The study demonstrated a functional success rate of approximately 66% following anterior lumbar spinal fusion after a mean follow-up of 8 years. There was a clear tendency for poorer prognosis for patients who had undergone previous spinal surgery, those aged above 45 years, those operated at the L4/L5 level and those who had responded poorly to the preoperative test brace. DPQ scores correlated well with radiological outcome.