Expandable pedicle screw instrumentation plus cement augmentation in surgery for severely os-teoporoic sin

吳子祥(Wu Zixiang，Dept Spine Surg，Xijing Hosp，4th Mil Med Univ，Xi’an 710032)…∥Chin J Orthop Trauma.－2011，13(2).－114～118

Expandable pedicle screw instrumentation plus cement augmentation in surgery for severely os-teoporoic sin

吳子祥(Wu Zixiang，Dept Spine Surg，Xijing Hosp，4th Mil Med Univ，Xi’an 710032)…∥Chin J Orthop Trauma.－2011，13(2).－114～118

ObjectiveTo evaluate short-teerm clinical and radiographic results of a novel expandable pedicle screw instrumentation combined with cement augmentation in surgery for severely osteoporotic spine.MethodsFrom October 2006 to October 2008，20 patients suffering from spinal diseases and severe osteoporosis were included in this clinical trial.They were 9 men and 11 women，with an average age of 59 years(range，43 to 73 years).The preoperative bone mineral density(BMD)scan revealed a mean BMD decrease of 3.2 ± 0.4.At one week，3 months，6 months and 12 months after surgery，plain radiography and three-dimensional CT scan were conducted to evaluate the spinal fusion and effectiveness of the instrumentation combined with cement augmentation，as well as the cement leakage.Functions were evaluated preoperatively and 3 months post-operatively with Japanese Orthopaedic Associatio(JOA)and visual analog scores(VAS).ResultsAltogether 168 expandable pedicle screws were implanted.The mean follow-up period was 26 months(range，12 to 38 months).The mean JOA and VAS improved respectively from 11.4 ± 2.6 and 7.0 ±1.4 before operation to 24.9 ± 1.6 and 2.1 ± 1.3 at 3 months after operation(P ＜0.05).The three-dimensional CT scan observed cement leakage anteriolaterally to the fractured vertebral body(2 cases)and to the adjacent disc(3 cases)without clinical sequelae.No cement leaked into the spinal canal.The spatial distribution of cement was satisfactory.There were no instances of loosening or pullout of the expandable pedicle screws.The screw-cement interface and cement-bone interface were excellent radiologically.Posterolateral radiologic fusion and bone healing around screws were achieved within 6 to 12 months after operation.ConclusionIn surgery for severely osteoporotic spine，excellent bone-screw interface and fixation strength can be achieved by expandable pedicle screw instrucmentation combined with cement augmentation，a feasible novel fixation alternative for orthopaedic surgeons.19 refs，1 fig，1 tab.

(Authors)