RESUMO
The apical hypokyphosis of scoliotic patients is thought to lead to decreased lung capacity and cause shortness of breath. Additionally, concave rod curve reduction is a problem in the correction of apical hypokyphosis in posterior spinal fusion surgery in adolescent idiopathic scoliosis (AIS). We investigated the contributions of rod rotation (RR) with an outrigger device, followed by differential rod contouring (DRC) with the outrigger attached to the concave rod, designed to prevent concave rod curve-flattening. We analyzed and compared the results of segmental pedicle screw fixation without the outrigger in 41 AIS patients with thoracic curves (Lenke type I, 25; type II, 16) to those corrected using the outrigger in 36 patients (Lenke type I, 24; type II,12). The changes in the Cobb angle, apical kyphosis of five vertebrae, thoracic kyphosis (TK, T4-12), correction rate, correction angle of apical vertebral rotation, spinal penetration index (SPi), and rib hump index (RHi) before and after surgery were measured, and the contribution of the outrigger was analyzed. The mean scoliosis correction rates without and with the outrigger were 72.1° and 75.6°, respectively (p = 0.03). Kyphosis of the five apical vertebrae and TK were significantly greater in the surgery with the outrigger (p = 0.002). Significantly greater improvements in SPi and RHi were also noted in the surgery with the outrigger (p < 0.05). The use of concave RR and convex DRC with the outrigger appear to be advantageous for correcting apical hypokyphosis, followed by the subsequent formation of TK. As a result, breathing problems are less likely to occur during daily life because of improvements in SPi and RHi.
RESUMO
Direct vertebral rotation (DVR) is the most widespread method to correct axial vertebral rotation. Differential rod contouring (DRC) also includes derotation, but not to the same extent as DVR. DVR requires additional surgical effort with potential consequences, which are absent in DRC; moreover, the data concerning the clinical benefits of apical derotation are not convincing. In the present study, clinical and radiological outcomes were compared in patients who underwent surgery for adolescent idiopathic scoliosis (AIS), having DVR and DRC vs. DRC only. In total, 73 AIS patients with curves of 40-85°, consecutively operated on by one surgeon, participated in this study and were followed up over 2 years. Scores from the SRS-22 questionnaire were analysed, the angles of trunk rotation (ATR) were measured with an inclinometer and a radiographic assessment of coronal and sagittal spinal profiles was conducted. In 38 cases, only DRC was performed, and in 35 DRC was performed and followed by DVR; the groups did not differ from an epidemiological point of view. Total SRS-22 scores after 2 years were similar in both groups (4.23 (±0.33) in DRC vs. 4.06 (±0.33) in DRC/DVR, p = 0.1). In all components of SRS-22, the differences were minor, with p being way above 0.05. The mean ATR in the DRC/DVR group was slightly smaller (8 ± 4°) than that of the DRC group (10 ± 5°), p = 0.16. Radiographic analysis did not show significant differences. The coronal curve was corrected by 66 ± 12% for DRC and 63 ± 15% for DVR, p = 0.28. Thoracic kyphosis in the DRC/DVR group increased by 1°, whereas in the DRC group the average kyphosis increased by 5° with a p value of 0.07. The complication rates were similar in both groups. This investigation did not show any advantages of the combination of DRC and DVR in scoliosis correction over DRC only, both radiologically and clinically, yet it affected intraoperative parameters, extending the operation time with only a minor increase in blood loss.
RESUMO
BACKGROUND CONTEXT: Although direct vertebral rotation (DVR) is now used worldwide for the surgical treatment of adolescent idiopathic scoliosis (AIS), the benefit of DVR in reducing vertebral body rotation in these patients has not been determined. PURPOSE: We investigated a possible additive effect of DVR on further reduction of vertebral body rotation in the axial plane following intraoperative rod rotation or differential rod contouring in patients undergoing surgical treatment for AIS. STUDY DESIGN/SETTING: The study was a prospective computed tomography (CT) image analysis. PATIENT SAMPLE: We analyzed the results of the two intraoperative procedures in 30 consecutive patients undergoing surgery for AIS (Lenke type I or II: 15; Lenke type V: 15). OUTCOME MEASURES: The angle of reduction of vertebral body rotation taken by intraoperative CT scan was measured and analyzed. Pre- and postoperative responses to the Scoliosis Research Society 22 Questionnaire (SRS-22) were also analyzed. METHODS: To analyze the reduction of vertebral body rotation with rod rotation or DVR, intraoperative cone-beam CT scans of the three apical vertebrae of the major curve of the scoliosis (90 vertebrae) were taken pre-rod rotation (baseline), post-rod rotation with differential rod contouring, and post-DVR in all patients. The angle of vertebral body rotation in these apical vertebrae was measured and analyzed for statistical significance. Additionally, differences between thoracic curve scoliosis (Lenke type I or II; 45 vertebrae) and thoracolumbar or lumbar curve scoliosis (Lenke type V; 45 vertebrae) were analyzed. Pre- and postoperative SRS-22 scores were evaluated in all patients. RESULTS: The mean (90 vertebrae) vertebral body rotation angles at baseline, post-rod rotation or differential rod contouring, and post-rod rotation or differential rod contouring or post-DVR were 17.3°, 11.1°, and 6.9°, respectively. The mean reduction in vertebral body rotation with the rod rotation technique was 6.8° for thoracic curves and 5.7° for thoracolumbar or lumbar curves (p<.00005). The mean additional reduction in rotation with the DVR technique was 3.4° for thoracic curves and 4.9° for thoracolumbar or lumbar curves (p<.00005). Direct vertebral rotation displayed a slightly but significantly greater additive effect in reducing rotation following initial reduction with rod rotation or differential rod contouring in thoracolumbar or lumbar than in thoracic curves. In the SRS-22 results, postoperative self-image was significantly better than preoperative image in both groups. CONCLUSIONS: Direct vertebral rotation contributed an additional reduction in vertebral body rotation in thoracic and thoracolumbar or lumbar curves. The DVR technique is likely to be more useful in thoracolumbar or lumbar curve scoliosis than in thoracic curve scoliosis.