Retrospective radiological outcome analysis following teriparatide use in elderly patients undergoing multilevel instrumented lumbar fusion surgery

Elderly patients with chronic nonresolving symptoms due to degenerative spine pathologies are prone to have poor surgical outcomes and hardware-related complications, especially following multilevel instrumented lumbar fusion surgeries. With intention of analyzing if teriparatide can be an effective adjunct therapy to surgical management, radiological outcomes are studied. Sixty-two elderly patients were divided into 2 similar groups. Group 1 (n=30; mean age=69.83 years; fusion levels=137; screws=269) had taken teriparatide (20 mcg SC injection, once daily) for a duration of 7.4±2.4 months following surgery and Group 2 (n=32; mean age=70.38 years; fusion levels=144; screws=283) did not take teriparatide. Radiological evaluation was done to determine the state of postero lateral fusion mass and to investigate the incidence of pedicle screw loosening at 1-year follow-up. Unilateral or bilateral bridging bone formation across the transverse process of adjacent vertebras showing continuous trabeculation suggestive of solid fusion was obtained in 66.7% patients in the teriparatide group and 50% patients in the control group (P=0.20). 13.4% of the total no. of screws showed signs of loosening in the teriparatide group, compared to 24.4% in the control group (P=0.001). Percentage of patients achieving solid fusion following teriparatide use was found to be more than that of the control group. This difference may have clinical importance but was not statistically significant. However, teriparatide use was more significantly influential in reducing the incidence of subsequent pedicle screw loosening.