To determine the cost-effectiveness of Lumbar Total Disc Replacement (LTDR) with circumferential spinal fusion surgery. Cost utility analysis. We prospectively reviewed a cohort of 32 consecutive patients who underwent LTDR between 2004 and 2008 with a mean follow-up for 3.75 years. Identical data was compared to a similar group of patients (n=37) who underwent fusion in our institution. Oswestry Disability Index, visual analogue scale, quality of life (SF-36) and NHS resource use. Cost-effectiveness was measured by the incremental cost per quality-adjusted life year (QALY) gained. QALY gains were estimated from SF-36 data using standard algorithms. There was no significant intergroup difference in the ODI, VAS and SF-36 pre and post-op. Both treatments produced statistically significant and equivalent improvements in mean health state utility at the 24-month follow-up (0.078 for LTDR, 0.087 for fusion). Costs were significantly lower with LTDR than with fusion due to a shorter mean procedure time (193.6 vs 377.4 minutes) and shorter length of stay (5.8 vs 7 days). The mean cost difference was £2,878 per patient. At 2 years, the cost per QALY gain of the lower-cost option (LTDR) was £48,892 although the cost effectiveness ratio would fall to below £30,000 if it is assumed that the patient benefits of LTDR last for at least 4 years. Both treatments led to significant improvements in patient outcomes which were sustained for at least 24 months. Costs were lower with LTDR which is effective and a more cost-effective alternative.
The footplate in the current available TDR is flat without any allowance for endplate concavity in the sagittal plane. To assess the morphology of the endplates of the lower lumbosacral in the sagittal plane, and to identify the frequently occurring shape patterns of the end plates at each level. Retrospective Study 200 consecutive magnetic reasonance imaging (MRI) scans of patients between the age of 30 and 60 years were analysed. In each endplate, the anteroposterior width, the height of concavity of the endplate, and the distance of the summit from the anterior vertebral body margin were noted. The shape of the endplate was noted as oblong (o) if the curve was uniform starting from the anterior margin and finishing at the posterior margin, eccentric (e) if the curve started after a flat portion at the anterior border and then curving backwards, and flat (f) if there is no curve in the sagittal plane. The shape of the end plate is mostly oblong at L3 IEP(59%), equally distributed between oblong and eccentric at L4 SEP (o=43.5%, e=46.5%), eccentric at L4 IEP (e=62.5%), eccentric at L5 SEP (e = 59.0%), eccentric at L5 IEP (e=94.0%), and flat at S1 SEP (f=82.5%). As there is a difference in the shape of the endplate at each level and they are not uniform, there is a need to focus on the sagittal shape of the footplate to avoid subsidence and mismatch of the footplate in cases of endplate concavity.
