167. Assessment of the efficacy of teriparatide (Forteo) in patients undergoing posterolateral lumbar spinal fusion: a double-blinded randomized pilot study

Abstract

BACKGROUND CONTEXT Lumbar spinal fusion is an increasingly common procedure for treating degenerative diseases of the lumbar spine. Non-solid fusion, or pseudarthrosis, at one year is a common complication associated with poor clinical outcomes and need for revision surgery. The risk of pseudarthrosis depends on the number of levels fused, the fusion material, and patient risk factors (osteoporosis, smoking, diabetes, etc.). Although there are multiple options for bone graft and osteoinductive materials, all have their benefits, side-effects and cost. Teriparatide is an injectable recombinant analog of parathyroid hormone that has been well-studied in its treatment of osteoporosis. However, no clinical studies of its effect on spinal fusion in humans have been published to date. PURPOSE To analyze the effect of teriparatide treatment on posterolateral spinal fusion in adults with degenerative diseases of the lumbar spine. STUDY DESIGN/SETTING Multicenter prospective double-blinded randomized study. PATIENT SAMPLE 60-90 year-olds with degenerative scoliosis, spondylolisthesis, or spondylosis at two medical centers undergoing instrumented posterolateral instrumented fusion >2levels. Use of BMP was excluded. OUTCOME MEASURES Pseudoarthrosis, screw loosening, PJK by CT. VAS, ODI, and Eq5D. METHODS Prospective randomized double-blind placebo-controlled pilot study performed at two large academic centers, UCSF and McGill University (Montreal). Included patients were aged 60-90 years with degenerative lumbar disease who were scheduled to undergo two-level or greater posterolateral lumbar spinal fusion. Patients were randomized in a 2:1 (Forteo:Placebo) manner. Patient were dosed 2 weeks pre-op and 10 weeks post-op. Patient derived outcomes were collected pre-op, 3, 6, 9, and 12 months. Fusions at 1 year were analyzed by helical CT. RESULTS A total of 36 patients completed the study. 58.3% (n=21) received teriparatide. 42.8% (n=9) reported an adverse event. Fusion rate of all patients was 47.2% (n=17); the remaining 52.8% (n=19) demonstrated pseudoarthrosis at 1 year. Fourty-seven percent of patients receiving teriparatide had a pseudoarthrosis, while 60% of placebo had a pseudoarthrosis. VAS, ODI, and Eq5D improved in all groups but no significant difference was found between groups. CONCLUSIONS Teriparatide appears to provide minimal benefit of avoiding pseudoarthroses in 60-90 year-olds undergoing thoracolumbar fusions. Teriparatide appears to have a fairly safe side effect profile. Further larger scale studies are warranted, possibly with the addition of BMP and/or bisphosphonates. FDA DEVICE/DRUG STATUS Unavailable from authors at time of publication.