Cervical discectomy and fusion with or without plate fixation. A randomized clinical and radiographic study on outcome and cost-utility

Abstract

The use of plate fixation in anterior cervical disc surgery has been popularized during the last decade despite incomplete knowledge regarding the efficacy of this treatment. This study was undertaken to evaluate the stabilizing effect of anterior cervical discectomy and fusion with and without plate fixation as well as the clinical outcome and the cost utility of these procedures.The study comprises 46 consecutive patients with neck pain, arm radiculopathy and with MRI verified herniated disc and/or spondylosis at one (27 patients) or two (19 patients) cervical disc levels. They were all on sick leave (mean 18 months) or had pension before surgery. 24 patients were randomized to plate fixation and 22 to surgery without internal fixation. The patients were followed-up after 2 years by an unbiased observer (neurologist). One patient was re-operated due to pseudarthrosis. At 2 years, 73% of the patients with a plate at one level were graded excellent/good with Odomís criteria compared to 67% of the patients without plate fixation. The corresponding numbers for two-level surgery were 89% with plate fixation and 70% without (n.s.). 41 patients were satisfied with their outcome of surgery and 30 patients returned to work within 2 years.Pre-operatively and after 2 years, the patients filled in three different questionnaires, the modified Million index, the Oswestry index and the Zung depression scale. A test-retest was performed for all three tests. The results of all tests correlated significantly to each other and also to the outcome according to Odomís criteria. Patients with an unsatisfying outcome with the Odomís criteria had a significantly higher Zung score (p= 0.024), Million score (p< 0.0005) and Oswestry index (p<0.0005) than those that had a good/excellent result after 2 years.In all patients but the first in the series, radiostereometric analysis (RSA) was used to evaluate the stability of the fusions. RSA examinations were done immediately postoperatively and after 2, 6 and 12 weeks and after 6, 12 and 24 months. In one level surgery the use of plate prevented deformation into kyphosis, but did not significantly affect the clinical outcome measured on visual analogue pain scale (VAS) for neck/arm pain, or the fusion rate. In two level surgery, the plate significantly prevented axial compression (p<0.01) and also deformation into kyphosis (p<0.01). These differences seemed to be clinically important because the patients with plate fixation had significantly lower arm pain (p=0.02) after 2 years. The outcome of surgery in the last 24 patients was further studied with another three health questionnaires, Euroqol, Hannover ADL and Von Korff pain scale. These questionnaires were administered preoperatively, and after 1 and 2 years. The costs of treatment were studied and the quality of life adjusted years gained (QUALY) was calculated. A subgroup of patients was identified, that did not improve with surgery. These patients related their symptoms to a whiplash like injury. The remaining group of patients improved significantly in all three scores at 2 years. The QUALY for these latter patients was estimated to 507 US$ provided that the improvement gained the first postoperative years would last during the patients remaining years