Comparison Of Surgical Outcomes Of Anterior Instrumention For Lenke5 AIS Between The Left And Right Curve And The Sagittal Spino-pelvic Alignment In Non-dvstrophic Thoracic Scoliosis Secondary To NF-1

Part one:Surgical outcomes of anterior instrumentation and fusion for Lenke5 AIS: A comparison between the left and right curveObjective To investigate the influence of curve direction on surgical outcomes of anterior single-rod instrumentation and fusion for Lenke5 adolescent idiopathic scoliosis (AIS).Methods A retrospective review was performed on 52 patients who underwent surgery for LenkeS AIS at our clinic between January 2005 and December 2009. According to the direction of thoracolumbar/ lumbar (TL/L) curve, patients were divided into the left-sided group (group L, n=38) and the right-sided group (group R, n=14). The following preoperative and follow-up radiographic measurements were compared between the two groups using the Student’s t test:curve magnitude, coronal balance, thoracic kyphosis, thoracolumbar junctional angle, lumbar lordosis, sagittal vertical axial, and so on.Results Preoperative Cobb angles of the TL/L and thoracic curves as well as the number of levels in TL/L curve were comparable between the two groups. Duration of follow-up for groups L and R averaged 3.1±0.9 years and 2.7±0.8 years, respectively. Compared with group L, operative time and intraoperative blood loss were both found to be higher in group R though not reaching statistical significance (208.8±41.4 min Vs.225.6±39.6 min, P=0.132; 236.5±159.6 ml Vs.284.4±164.7 ml, P=0.345). The average TL/L curve correction was 66.7% in group L and 64.4% in group R (P=0.808), and at the last follow-up, loss of the TL/L curve correction averaged 4.6% and 5.1%, respectively (P=0.992). With respect to the thoracic curve, the average correction and correction loss at final follow-up were found to be similar between the two groups (P=0.886 and P=0.759, respectively). Complications occurred in 4 of the patients, with one proximal junctional kyphosis and two distal adding-on presenting in group L, as well as one proximal adding-on in group R. There were no neurologic complications, vascular injury or implant failure till the last follow-up.Conclusion Anterior single-rod instrumentation remains an effective surgical treatment for Lenke type 5 AIS, and there was no statistically significant difference comparing the left and the right TL/L curves.Part two:Sagittal spino-pelvic alignment in non-dystrophic thoracic scoliosis secondary to NF-1:a comparison with AIS and normal controlObjective To compare sagittal spino-pelvic alignment in neurofibromatosis type-1 (NF-1) associated with non-dystrophic thoracic scoliosis, adolescent idiopathic scoliosis (AIS), and normal control.Materials and Methods Fifteen NF-1 patients with non-dystrophic thoracic scoliosis (group NF-1) less than 70 degrees were reviewed. Fifteen AIS patients (group AIS) matched for age, gender, curve pattern and Cobb angle were selected for comparison. In addition, age-and gender-matched healthy adolescents were recruited as control (group CTL, n=30). On standing full-spine lateral X-rays, the following parameters were measured: thoracic kyphosis (TK), thoracolumbar junctional angle (TLJ), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), spinal tilt (ST) and spinal-sacral angle (SSA).Results For the NF-1 group, the TK of 13 patients was within the normal range (10°-40°) with hyperhyphosis and hypohyphosis presenting in 1 each. The average TK of the NF-1 group was significant larger than that in the AIS group (5.6°± 7.6° versus 16.5°± 5.4°, P<0.05), and significant difference was found between the two groups in LL (-53.8°versus-47.8°, P<0.05). However, no significant differences were noted between the NF-1 and the CTL group in all eight sagittal parameters.Conclusion The sagittal profile in non-dystrophic thoracic scoliosis secondary to NF-1 is similar to that in age- and gender-matched healthy adolescents, that is, either significant hypohyphosis, an obvious characteristic in AIS patients, or obvious hyperhyphosis occurs in NF-1 group. The postoperative sagittal decompensation might not be related to the preoperative sagittal alignment in NF-1 patients with non-dystrophic thoracic scoliosis.