Surgical Outcomes of Osteoporotic Vertebral Collapse: A Retrospective Study of Anterior Spinal Fusion and Pedicle Subtraction Osteotomy

摘要

The purpose of this retrospective study was to demonstrate the surgical outcomes of anterior spinal fusion (ASF) and posterior subtraction osteotomy (PSO) for osteoporotic vertebral collapse (OVC). Forty patients who underwent surgery for OVC at the thoracolumbar junction with neurological deficits were included in this study. ASF was primarily chosen for patients without vertebral compression fracture at other levels, and PSO was chosen for patients with more severe kyphosis or with multiple vertebral fractures. ASF was performed in 26 patients and PSO was performed in 14 patients. We evaluated the pre- and postoperative clinical status consisting of pain, gait, paralysis, and bladder function analysis. Additionally, pre- and postoperative kyphosis, correction angle, correction loss, and upright balance were investigated radiologically. Improvements in pain level, gait, paralysis, and bladder function were obtained in both groups. Average correction angles in the ASF and PSO groups were 16 and 37, respectively. Average correction losses at the final follow-up in the ASF and PSO groups were 7 and 13, respectively. Newly developed postsurgical vertebral compression fracture adjacent to the level of instrumentation was observed in four patients (15%) in the ASF group and in 11 patients (79%) from the PSO group. ASF provided satisfactory outcomes for patients with thoracolumbar OVC, who have no vertebral compression fracture at other levels. Although PSO has benefits for the correction of kyphosis, several problems persist with this procedure, especially for patients with severe osteoporosis. Keywords: osteoporotic vertebral collapse, anterior spinal fusion, pedicle subtraction osteotomy, surgical outcome, thoracolumbar junction Osteoporotic vertebral fracture is a significant injury producing a functional loss in activities of daily living for an increasing elderly population. Osteoporotic vertebral compression fracture is conventionally treated conservatively with rest, immobilization, analgesics, brace therapy, and physical therapy. However, these compression fractures sometimes fail to heal, resulting in progressive collapse and/or pseudarthrosis. This situation has been defined as osteoporotic vertebral collapse (OVC). 1 2 Furthermore, OVC at the thoracolumbar junction often causes neurological deficits. Development of neurological deficits is typically associated with several factors, including direct neural compression from retropulsed bony fragments in the spinal canal, abnormal neural alignment subsequent to progressive kyphosis, and dynamic neural damage due to abnormal mobility at the fracture site. Decompression of the neural elements and restoration of spinal stability are essential in the surgical management for OVC. However, not only local factors but also general problems have to be considered when treating OVC. Patients with OVC have relatively severe osteoporosis and often possess multiple preexisting vertebral compression fractures, leading to technical difficulty in achieving spinal reconstruction. General spinal deformity is also a significant problem for these elderly patients such that local restoration of spinal alignment sometimes leads to adjacent spinal problems. 3 4 Surgical treatment for OVC is tailored for the individual patient presentation due to the multiple comorbidities in the osteoporetic population. We have selected two common surgical interventions for OVC at the thoracolumbar junction that have been in use since 1998: anterior spinal fusion (ASF) and pedicle subtraction osteotomy (PSO). The purpose of this retrospective study was to demonstrate surgical outcomes of these two separate procedures.