Osteoporotic pedicle screw: Review of various types of pedicle screw and cement augmentation

Abstract

Osteoporosis is a major global health problem and its complication especially compression fracture of the spine has become a burden of physical function in postmenopausal women and elderly. Screw loosening and pulling out are still major issues in pedicle screw placement in osteoporotic bone. Various studies about pedicle screw have been investigated. Pedicle screw using expandable pedicle screw (EPS), cannulated pedicle and fenestrated pedicle screw with cement augmentation, and anchor type of pedicle screw show excellent outcomes in biomechanical studies (pull-out, insertional torque), micro-CT analysis, and histological analysis compared to conventional solid pedicle screw. There is no study comparing each type of these screws. PMMA cement augmentation is superior to cement-based augmentation, but it shows more complication than calcium based-cement. Hydroxyapatite (HA) have shown better pull-out force six times higher than solid screw without augmentation, but there is no comparative study between PMMA and HA. This work aims to investigate various types of pedicle screw and cement augmentation used in osteoporotic bone. It has been shown that fenestrated and cannulated pedicle screw with cement augmentation, expandable pedicle screw, and anchor type pedicle screw with various type of augmentation shows benefit in osteoporotic bone screw placement.