Introduction: Lumbar spine fusion is now an evidence based treatment principle of low back pain. However, much controversy still exists on the choice of surgical technique. Since the source of pain may be located in the intervertebral disc, a disc removal seems logical. Instrumented and non-instrumented fusion as well as PLIF have failed to restore lumbar lordosis.

Aim: The aim of the present study was to study fusion rates, functional outcome, lumbar lordosis and complications in a RCT design using radiolucent cages and titanium instrumentation.

Materials and methods: 148 patients were bloc randomised to either PLF (72) or ALIF + PLF (76) from April 1996 to February 2000. Inclusion criteria were disc degeneration or spondylolisthesis groups 1 and 2; Age> 20 years and < 65 years. Life quality was assessed pre-operatively, one and two years post-operatively by Dallas Pain Questionnaires and by Back and Leg Pain rating scales from 0 to 10.

Results and discussion: A preliminary follow-up at one year post-op of 56 patients in each group showed no difference in admission or blood loss (921/1008 ml) and peroperative morbidity, although the operation time was significantly longer in the ALIF+ group (mean 219/344 minutes). Sagittal lordosis was restored and maintained in the ALIF+ group (p< 0.01), in contrast to the PLF group. There was no difference in functional outcome. Average back pain lasting 14 days scored 4.5 in each group, and leg pain 3.2 in the ALIF+ group versus 4 in the PLF group (NS). The re-operation rate was significantly higher in PLF after both one and two years with 9% refusion versus no refusion in the ALIF+ group. Global patient satisfaction was equal in both groups: 78% versus 76% at one year and at two years 75% versus 80% in PLF and ALIF+ groups.

Conclusion: ALIF+ fusion demands higher operative resources compared to PLF, however ALIF+ restores lordosis and provides the highest union rate and significantly fewer reoperations. A cost/effectiveness analysis after long-term follow-up may also favour the ALIF+ treatment due to improved lordosis and perhaps less degeneration of adjacent motion segments.