Steven W. Hwang, Ornella M. Dubaz, Robert Ames, Alex Rothkrug, Jeff S. Kimball and Amer F. Samdani
The thoracic rib hump, caused by axial rotation of the spine, is one of the most dissatisfying cosmetic features associated with adolescent idiopathic scoliosis (AIS). However, advances in instrumentation and surgical techniques, such as direct vertebral body derotation (DVBD), have allowed improved correction in the axial plane and the rib hump. In cases of thoracolumbar/lumbar curves (Lenke Type 5), the lumbar prominence can be equally disfiguring and is often associated with waist asymmetry, another cosmetic concern. Although DVBD has been evaluated in the thoracic spine, little is known about its impact on the lumbar spine. The authors investigated the outcomes of DVBD on the lumbar prominence.
A prospectively collected multicenter database was queried for pediatric patients with AIS and Lenke Type 5 curves. All patients who underwent thoracoplasty procedures were excluded. A total of 34 patients underwent surgical correction via a posterior-only approach using pedicle screw constructs. Nineteen patients underwent concurrent DVBD, and the remaining 15 patients served as a control group and did not undergo DVBD. All patients had a minimum of 2 years of follow-up.
The mean age of the entire cohort was 14.9 ± 2.3 years, and the majority of patients were female (88%). All patients had Lenke Type 5C curves with a mean major curve of 46.0° ± 8.7°, which corrected to 13.7° ± 7.2° (70% correction). A mean of 10.7 ± 3.0 levels were fused. Only thoracic kyphosis was significantly different between the groups preoperatively. Similarly, postoperative radiographic parameters were comparable between the groups, with equivalent percentages of correction. Although improvement in the thoracic rib hump was comparable between the groups, the DVBD group had 56.2% correction of the lumbar prominence, and the control group had 76% improvement (p = 0.05).
Although DVBD has been a valuable tool in the management of AIS, the authors' results suggest that its application for thoracolumbar curves may be limited. Further analysis with a larger cohort is required to better ascertain the impact of DVBD on thoracolumbar curves.
Steven W. Hwang, Amer F. Samdani, Ben Wormser, Hari Amin, Jeff S. Kimball, Robert J. Ames, Alexander S. Rothkrug and Patrick J. Cahill
Pedicle screw fixation has been theorized to provide better correction of scoliotic deformity, but controversy over the benefits of pedicle screw–only constructs remains, and the longer-term impact of pedicle screw fixation as compared with hybrid constructs is unclear. In this study, a retrospective review of a prospectively collected database was conducted to determine the longer-term impact of pedicle screw fixation as compared with hybrid constructs in patients with adolescent idiopathic scoliosis (AIS).
The authors retrospectively reviewed a multicenter database of pediatric patients (ages ≤ 18) from 1995 to 2006 and identified 127 patients with Lenke Type 1–4 AIS curves with a minimum 5 years of follow-up. Patients were divided into 2 cohorts based on whether they had undergone pedicle screw fixation or fixation with hybrid constructs.
The mean main thoracic curvature of 56.1° ± 13.0°, which corrected to 14.9° ± 9.3°, translated into a mean correction of 73% (p < 0.01). The curve was 19.4° ± 10.6° at 2-year follow-up and 20.5° ± 10.4° at 5 years. When comparing preoperative parameters between the groups, differences were noted in the magnitude of the main thoracic curve (p = 0.04), flexibility of the main thoracic curve (p = 0.02), coronal balance (p = 0.04), T2–12 kyphosis (p = 0.02), and sex (p = 0.02). The pedicle screw cohort had fewer spinal segments instrumented (p < 0.01), fewer anterior releases performed (p = 0.02), and fewer thoracoplasties performed (p < 0.01). By 5 years of follow-up, significant differences were apparent between the two cohorts with respect to upper thoracic curvature (p = 0.01), T2–12 (p = 0.02) and T5–12 (p = 0.02) kyphosis, lumbar lordosis (p < 0.01), and sagittal balance (p = 0.01).
Although some preoperative differences did exist, outcomes were comparable between hybrid and screw constructs at 2 and 5 years. However, hybrid constructs required more concurrent anterior releases and thoracoplasties to achieve similar results.
Presented at the 2013 Joint Spine Section Meeting
James T. Bennett, Jane S. Hoashi, Robert J. Ames, Jeff S. Kimball, Joshua M. Pahys and Amer F. Samdani
Several studies of the outcomes of patients with adolescent idiopathic scoliosis (AIS) with thoracolumbar and lumbar curves after treatment with posterior pedicle screws have been reported, but most of these studies reported only 2-year follow-up. The authors analyzed the radiographic and clinical outcomes of patients with thoracolumbar and lumbar curves treated with posterior pedicle screws after 5 years of follow-up.
A multicenter database was retrospectively queried to identify patients with AIS who underwent spinal fusion for Lenke 3C, 5C, and 6C curves. Radiographs from the following times were compared: preoperative, first follow-up visit, 1-year follow-up visit, 2-year follow-up visit, and 5-year follow-up visit. Chart review included scoliometer measurements, Scoliosis Research Society (SRS)–22 questionnaires, and complications requiring return to the operating room.
Among 26 patients with Lenke 3C, 5C, and 6C curves, the mean (± SD) age was 14.6 ± 2.1 years. From the time of the preoperative radiographs to the 5-year follow-up radiographs, there was a statistically significant improvement in the mean coronal lumbar Cobb angles (p < 0.0001), and from the time of the first postoperative radiographs to the 5-year follow-up radiographs, the lumbar curve remained stable (p = 0.14). From the time of the preoperative radiographs to the 5-year follow-up radiographs, there was a statistically significant improvement in the mean coronal thoracic Cobb angles (p < 0.0001), and from the time of the first postoperative radiographs to the 5-year follow-up radiographs, the thoracic curve remained stable (p = 0.10). From the first postoperative visit to the 5-year follow-up visit, the thoracic kyphosis (T5–12) remained stable (p = 0.10), and from the time of the preoperative radiographs to the 5-year follow-up radiographs, the lumbar lordosis (T-12 to top of sacrum) remained stable (p = 0.44). From the preoperative visit to the 5-year follow-up visit, the coronal balance improved significantly (p < 0.05) and remained stable from the first postoperative visit to the 5-year follow-up visit (p = 0.20). The SRS-22 total scores improved significantly from before surgery to 5 years after surgery (p < 0.0001). No patients required reoperation because of complications.
Correction of the coronal, sagittal, and axial planes in this cohort of patients was maintained from the first follow-up measurements to 5 years after surgery. In addition, at 5 years after surgery total SRS-22 scores and inclinometer readings were improved from preoperative scores and measurements.
Steven W. Hwang, Mina G. Safain, Joseph J. King, Jeff S. Kimball, Robert Ames, Randall R. Betz, Patrick J. Cahill and Amer F. Samdani
Almost all pediatric patients who incur a spinal cord injury (SCI) will develop scoliosis, and younger patients are at highest risk for curve progression requiring surgical intervention. Although the use of pedicle screws is increasing in popularity, their impact on SCI-related scoliosis has not been described. The authors retrospectively reviewed the radiographic outcomes of pedicle screw–only constructs in all patients who had undergone SCI-related scoliosis correction at a single institution.
Medical records and radiographs from Shriner's Hospital for Children–Philadelphia for the period between November 2004 and February 2011 were retrospectively reviewed.
Thirty-seven patients, whose mean age at the index surgery was 14.91 ± 3.29 years, were identified. The cohort had a mean follow-up of 33.2 ± 22.8 months. The mean preoperative coronal Cobb angle was 65.5° ± 25.7°, which corrected to 20.3° ± 14.4°, translating into a 69% correction (p < 0.05). The preoperative coronal balance was 24.4 ± 22.6 mm, with a postoperative measurement of 21.6 ± 20.7 mm (p = 1.00). Preoperative pelvic obliquity was 12.7° ± 8.7°, which corrected to 4.1° ± 3.8°, translating into a 68% correction (p < 0.05). Preoperative shoulder balance, as measured by the clavicle angle, was 8.2° ± 8.4°, which corrected to 2.7° ± 3.1° (67% correction, p < 0.05). Preoperatively, thoracic kyphosis measured 44.2° ± 23.7° and was 33.8° ± 11.5° postoperatively. Thoracolumbar kyphosis was 18.7° ± 12.1° preoperatively, reduced to 8.1° ± 7.7° postoperatively, and measured 26.8° ± 20.2° at the last follow-up (p < 0.05). Preoperatively, lumbar lordosis was 35.3° ± 22.0°, which remained stable at 35.6° ± 15.0° postoperatively.
Pedicle screw constructs appear to provide better correction of coronal parameters than historically reported and provide significant improvement of sagittal kyphosis as well. Although pedicle screws appear to provide good radiographic results, correlation with clinical outcomes is necessary to determine the true impact of pedicle screw constructs on SCI-related scoliosis correction.
Phoenix, Arizona • March 6–9, 2013