Strategies of spinal fusion on osteoporotic spine

Abstract

The prevalence of osteoporosis has been increasing globally. Recently surgical indications for elderly patients with osteoporosis have been increasing. However, only few strategies are available for osteoporotic patients who need spinal fusion. Osteoporosis is a result of negative bone remodeling from enhanced function of the osteoclasts. Because bone formation is the result of coupling between osteoblasts and osteoclasts, anti-resorptive agents that induce osteoclast apoptosis may not be effective in spinal fusion surgery, necessitating new bone formation. Therefore, anabolic agents may be more suitable for osteoporotic patients who undergo spinal fusion surgery. The instrumentations and techniques with increased pullout strength may increase fusion rate through rigid fixation. Studies on new osteoinductive materials, methods to increase osteogenic cells, strengthened and biocompatible osteoconductive scaffolds are necessary to enable osteoporotic patients to undergo spinal fusion. When osteoporotic patients undergo spinal fusion, surgeons should consider appropriate osteoporosis medication, instrumentation and technique.

Keywords: Fusion; Osteoblast; Osteoclast; Osteoporosis; Spine.

Fig. 1

This scheme shows the basic mutilcellular units (BMU) in resorption cavity. After the lining cells prepare the damaged bone surface, osteoclasts as fused cell preosteoclasts absorb the bone in a BMU and release several growth factors that promote osteoblasts.

Fig. 2

The scheme shows the different ossifications in center posterolateral fusion. VB : vertebral body, TP : transverse process, BG : bone graft.