Instrumentation of the osteoporotic spine: biomechanical and clinical considerations

BACKGROUND CONTEXT: Osteoporosis is a major health-care problem that is increasing in magnitude with the aging population. Such patients are more prone to develop painful and debilitating spinal deformities but are difficult to treat. Currently, no definitive treatment algorithm has been established. PURPOSE: To review the failure modes of instrumentation and novel surgical treatments of spinal deformities in patients with osteoporosis with the goal of improving surgical care. STUDY DESIGN/SETTING: Review article. METHODS: We systematically searched PubMed for articles regarding instrumentation failure modes and surgical treatments of spinal deformities in patients with osteoporosis and summarized current treatment options. RESULTS: The surgical treatment options are severely limited because of the tendency for instrument failure secondary to pullout and subsidence, leading to revision procedures; multiple levels and multiple fixation points are recommended to minimize the risk. The literature supports the use of vertebroplasty in conjunction with pedicle screw-based instrumentation for treating more severe spinal deformities. Other techniques and modifications with evidence of reduced failure risk are bicortical screws, hydroxyapatite coatings, double screws, and expandable screws. Anterior approaches may provide another avenue of treatment, but only a few studies have been conducted on these implants in patients with osteoporosis. CONCLUSIONS: Spinal deformities in patients with osteoporosis are difficult to treat because of their debilitating and progressive nature. Novel surgical approaches and instruments have been designed to decrease construct failures in this patient population by reducing implant pullout, subsidence, and incidence of revision surgery. The success of these techniques depends on integrating biomaterial, biologic, and biomechanical aspects with clinical considerations. Synthesizing this myriad of aspects will lead to improved treatment options for patients with osteoporosis who are suffering from spinal deformities. (C) 2011 Elsevier Inc. All rights reserved.