Strategies for Vertebral Augmentation and Increasing Pedicle Screw Purchase in the Osteoporotic Spine Surgery

Kim, Jin Hwan

Abstract

The surgical treatment of osteoporotic bone is remarkably increasing with aged population. The problem of osteoporotic bone surgery is bone-implant failure such as screw pullout or cutout due to poor bone quality. In the osteoporotic spine. pedicle screw fixation is highly correlated with the bone mineral density. In order to enhance the fixation stability at osteoporotic spine surgery, we need a systematic approach with meticulous preoperative planning, careful intraoperative procedure and detail postoperative management. A couple of principle to reduce stress on bone implant interface are extensive release for the deformity, avoiding forceful reduction, adding anterior structural graft, good sagittal balance and avoiding to increase strain at spinal transition zone. Meticulous insertion technique such as preservation of dorsal cortex at hole, untapping of hole, anterior cortex penetration and proper screw trajectory are important. The pedicle screw design and augmentation can also affect the fixation stability. The screw with larger diameter and expandable shape have some advantage for pullout strength. The most common method for vertebral body augmentation is adding with bone cement. The other techniques for augmentation are multiple point fixations with bone graft, additional laminar hook or sublaminar wire and additional polyethylene tape. Postoperative management with brace and medication can enhance the bone union.