THE CLINICAL AND RADIOLOGICAL OUTCOME OF A PROSPECTIVE RANDOMISED CONTROLLED TRIAL OF CIRCUMFERENTIAL LUMBAR SPINAL FUSION: FEMORAL RING ALLOGRAFT VERSUS TITANIUM CAGE

Abstract

Aim: The clinical and radiological outcomes of a prospective randomised controlled trial comparing Femoral Ring Allografts (FRA) to Titanium Cages (TC) for circumferential fusion are presented.

Methods: Eighty-three patients were recruited fulfilling strict entry requirements (> 6 months chronic discogenic Low Back Pain (LBP), failure of conservative treatment, one or two level discographically-proven discogenic pain). Five patients were excluded on technical infringements (unable to insert TC or FRA). From 78 patients randomised, 37 received FRA and 41 received TC. Posterior stabilisation was achieved with translaminar or pedicle screws. Patients completed the Oswestry Disability Index (ODI), Visual Analogue Scale (VAS) for back and leg pain, the Short-Form 36 (SF-36) pre-operatively and 6, 12 and 24 months post-operatively. Assessment of fusion was made by a panel of 6 individuals examining radiographs taken at the same specified time points.

Results: Clinical outcomes were available for all 83 patients (mean follow-up 28 months, range 24–75). Baseline demographic data showed no statistical difference between groups (p< 0.05). For patients receiving FRA, mean VAS (back pain) improved 2.0 points (p< 0.01), mean ODI improved 15 points (p=< 0.01), and mean SF-36 scores improved by > 11 points in 6 of 8 domains (p< 0.03). For patients receiving TC, mean VAS improved 1.1 points (p=0.004), mean ODI improved 6 points (p=0.01), and SF-36 improved significantly in only two of eight domains. Revision procedures and complications were similar in both groups. For the FRA group, 27 levels were fused from a total of 42 assessed (64.2%). For the TC group, 33 levels were fused from a total of 55 assessed (60%). This difference was not statistically significant p> 0.2.

Conclusion: The use of FRA in circumferential lumbar fusion was associated with superior clinical outcomes when compared to those observed following the use of TC. Both groups had similar fusion rates.