Date of Award

January 2011

Document Type

Thesis

Degree Name

Medical Doctor (MD)

Department

Medicine

First Advisor

Gary Friedlaender

Second Advisor

Joseph M. Lane

Subject Area(s)

Medicine

Abstract

Fusion of the spine requires de novo bone formation and remodeling, processes that rely heavily upon the action of the osteoblast and the osteoclast. Therapies for osteoporosis act upon the osteoblast/osteoclast complex in order to increase bone mineral density. Prior studies have demonstrated the ability of these medication to modify fracture healing, a process that is biologically similar to spine fusion. The goal of this systematic review is to evaluate the available evidence on the potential impact of bisphosphonates and parathyroid hormone on fusion rate and fusion quality in spinal arthrodesis.

A systematic review of the MEDLINE, EMBASE, and BIOSIS databases was performed. Exclusion criteria were then applied to the search results in order to capture only controlled studies evaluating the effect of either bisphosphonates or parathyroid hormone on fusion rate or fusion quality (defined as the histological, microstructural, or biomechanical characteristics of the fusion mass). The results of included studies were then aggregated and examined for consensus on the effect of these medications on spine fusion. Studies were also evaluated for statistical power and their ability to model the clinical scenario of interest.

The literature contained only animal studies relating to the study question. The available data suggests that bisphosphonates may decrease the fusion rate and result in less histologically mature and biomechanically weaker fusion masses. Parathyroid

hormone appears to improve the fusion rate and improve fusion mass microstructure, but data on its effect on fusion mass biomechanics is lacking. Future studies in humans are

needed to guide the medical management of patients with osteoporosis who are undergoing spine fusion.

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