Combined anterior/posterior (A/P) spinal fusion with instrumentation has been used for many years in the treatment of adult thoracolumbar and lumbar (TL/L) scoliosis. However, the risk factors for complications and poor clinical outcomes with this procedure are not well known.
To assess the risk factors for poor clinical outcomes in a series of adult lumbar or scoliosis patients undergoing combined A/P-instrumented spinal fusion.
This study was a retrospective case series of surgically treated adult lumbar or thoracolumbar scoliosis patients.
From 1998 to 2006, 57 patients with diagnoses of adult idiopathic scoliosis or degenerative TL/L scoliosis underwent combined A/P spinal instrumentation and fusion at 1 institution, performed by 1 senior author.
The preoperative and postoperative outcome measurements included self-report measurements, physiological measurements, and functional measurements.
Materials and Methods:
A retrospective review of this patient group was performed to evaluate patient satisfaction, functional outcomes, pain, curve progression, and complications. Radiographic measurements included coronal balance, sagittal vertical axis, Cobb angle, thoracic kyphosis, lumbar lordosis, and pelvic incidence preoperatively, immediately postoperatively, and during follow-up. In terms of risk factors, bone mineral density, body mass index, age, kyphosis, and fusion to the sacrum were reviewed. Postoperative Scoliosis Research Society Patient Questionnaire outcome scores, Oswestry Disability Index (ODI), and anterior surgical site pain (ASSP) were also evaluated. Means were compared with the Student t test and the χ2 test. Logistic regression analyses were used to predict the probabilities and the odds ratios (ORs) of the risk factors for poor clinical outcomes. A P-value of <0.05 with a confidence interval of 95% was considered significant.
Fifty patients had adult idiopathic scoliosis, and 7 patients had degenerative scoliosis. The average age at surgery was 53.8 years (34–74 y), and the average follow-up was 4.8 years (2–11 y). Coronal correction for thoracic, thoracolumbar, and lumbosacral curves improved significantly. The degree of sagittal curve and coronal and sagittal balance were not significantly changed after surgery or at the final follow-up. ODI, the pain intensity domain of the ODI, and ASSP were significantly worse in obese and overweight patients, whereas OR time, estimated blood loss, and number of fused vertebrae were not different in the entire group (P=0.03 for ODI, P=0.002 for pain domain of ODI, and P=0.003 for ASSP). Logistic regression analyses for the risk factors of poor clinical outcomes indicated obesity and overweight as risk factors for poor clinical outcomes (OR=6.25 for ODI and 5.88 for ODI pain intensity score). A significantly higher rate of major complications occurred in this group compared to the entire group (30.4%, P=0.04). Low bone mineral density, old age, kyphosis, and fusion to the sacrum were not risk factors for poor clinical outcomes.
Despite the good function scores and acceptable pain levels in most patients, the ODI scores of obese and overweight patients were worse compared to the rest of the patients in this study. Significantly worse scores on the pain intensity domain of the ODI and ASSP differences were likely caused by extensive dissection of the abdominal wall and psoas muscles and the technical difficulty of achieving an anterior approach to the thoracolumbar spine. Radiographs revealed no progression of the TL/L curves. This study indicates that obesity and overweight are potential risk factors for combined A/P-instrumented spinal fusion in patients with adult TL/L scoliosis, perhaps due to the technical difficulty of achieving an anterior approach to the thoracolumbar spine.