Cost-effectiveness of confirmatory techniques for the placement of lumbar pedicle screws

There is considerable variation in the use of adjunctive technologies to confirm pedicle screw placement. Although there is literature to support the use of both neurophysiological monitoring and isocentric fluoroscopy to confirm pedicle screw positioning, there are no studies examining the cost-effectiveness of these technologies. This study compares the cost-effectiveness and efficacy of isocentric O-arm fluoroscopy, neurophysiological monitoring, and postoperative CT scanning after multilevel instrumented fusion for degenerative lumbar disease.

Retrospective data were collected from 4 spine surgeons who used 3 different strategies for monitoring of pedicle screw placement in multilevel lumbar degenerative disease. A decision analysis model was developed to analyze costs and outcomes of the 3 different monitoring strategies. A total of 448 surgeries performed between 2005 and 2010 were included, with 4 cases requiring repeat operation for malpositioned screws. A sample of 64 of these patients was chosen for structured interviews in which the EuroQol-5D questionnaire was used. Expected costs and quality-adjusted life years were calculated based on the incidence of repeat operation and its negative effect on quality of life and costs.

The decision analysis model demonstrated that the O-arm monitoring strategy is significantly (p < 0.001) less costly than the strategy of postoperative CT scanning following intraoperative uniplanar fluoroscopy, which in turn is significantly (p < 0.001) less costly than neurophysiological monitoring. The differences in effectiveness of the different monitoring strategies are not significant (p = 0.92).

Use of the O-arm for confirming pedicle screw placement is the least costly and therefore most cost-effective strategy of the 3 techniques analyzed.