Index level mobility after total lumbar disc replacement: is it beneficial or detrimental?

Analysis of segmental and total lumbar range of motion (ROM) before and after total lumbar disc replacement.

To examine the relationship between absolute segmental and total lumbar ROM and evolution of ROM on clinical outcome.

At the moment, data are scarce with regard to the evolution of total lumbar ROM (t-ROM) and segmental ROM (s-ROM) after total lumbar disc replacement. Moreover, the influence of ROM on clinical outcome still is unclear and remains a matter of controversial debate. METHODS.: Forty patients operated on for mono- or bisegmental symptomatic degenerative disc disease with a total of 45 artificial discs (ProDisc-L, Synthes) were analyzed. Pre- and postoperative s-ROM and t-ROM were measured on flexion/extension radiographs. The Oswestry Low Back Pain Disability Questionnaire and the Short Form 36 Health Survey were obtained pre- and postoperatively with a minimum follow-up of 3 years (37-64 months).

Neither the s-ROM (pre-/postoperatively: 6.9 degrees/7.3 degrees) nor the t-ROM (pre-/postoperatively: 34.9 degrees/35.8 degrees) did change significantly after implantation of an artificial disc. Postoperatively, there was an increase of s-ROM (t-ROM) in 40% (40%), a decrease in 35% (30%), and no change in 25% (30%) of the patients. A significant inferior clinical outcome only was observed in patients with decreased t-ROM. The resulting postoperatively s-ROM had no significant impact on outcome.

Neither the absolute s-ROM nor the evolution of s-ROM (increase, decrease, unchanged) was positively correlated with better clinical outcome. Although a positive correlation was observed with regard to t-ROM.