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<ul><li> 1. Abstracts from: The 1st International Congress on Early Onset Scoliosis and Growing Spine November 2-3, 2007 Madrid, Spain Chairman: Behrooz A. Akbarnia, M.D. Free Papers Paper #1 The Effect of Early Anterior Fusion on Spinal Canal Size: An Immature Porcine Model Muharrem Yazici, M.D., Guney Yilmaz, M.D., Murat Pekmezci, M.D., Kenan Daglioglu, M.D., FC Oner, M.D. Introduction Neurocentral cartilage (NCC) is located at the posterior 2/3 of vertebrae and responsible for the growth of the pedicles and posterior vertebral body. The aim of this study is to evaluate the effect of anterior spinal instrumentation and fusion on the development of vertebral body in porcine model. Materials &amp; Methods Twelve 8 week-old domestic pigs had CT scans preoperatively and underwent anterior circumferential discectomy of the L3-L4 and L4-L5 discs. Anterior spinal instrumentation was performed between L3 and L5 (L4 skipped). After 6 months their vertebrae were evaluated with CT scan for the presence of anterior fusion and vertebral canal size. The area of vertebral segments adjacent to proximal and distal instrumented segments was used as control level area (AC), average area of L3 and L5 was used as area change in instrumented levels (AI), and area of L4 was used as area change at arthrodesis level (AA). The percent increases in the canal area and total canal area were compared. Results All subjects had documented anterior fusion. There was no difference in the canal diameters of three groups preoperatively(AA: 0.70cm2, AI: 0.70cm2, AC: 0.68cm2; p0.05). At the end of 6 months average canal diameter was significantly lower than control group in the arthrodesis and instrumentation groups (AA: 1.20cm2, AI:1.24cm2 , AC:1.41cm2; p0.001). The average canal diameters of the arthrodesis and instrumentation groups were similar (AA: 1.20 cm2, AI: 1.24 cm2; p0.05). The average percent increase in the canal area was significantly lower than the control levels in the arthrodesis and the instrumented segments (AA: 72.6%, AI: 77.1%, AC: 110.1%; p0.001). The percent increase in the canal area between the arthodesis and instrumented segment was similar (AA: 72.6%, AI: 77.1%; p0.05). Conclusion This study demonstrated that anterior spinal arthrodesis or instrumentation in the immature spine may result in iatrogenic spinal stenosis. </li></ul> <p> 2. Paper #2 Growing Rod Instrumentation and Vertebral Body Growth: A Radiological Investigation in Immature Pigs Guney Yilmaz, M.D., Muharrem Yazici, M.D., Gokhan Demirkiran, M.D., Kenan Daglioglu, M.D., Cenk Ozkan, M.D. Introduction Distraction forces applied on growth plate of appendicular skeleton stimulate longitudinal growth. However the effect of distraction forces on axial skeletal growth has not been fully investigated yet. The aim of this study is to evaluate the vertebral body growth under distraction forces in immature pigs treated with growing rod technique. Materials &amp; Methods Eight 8-week-old domestic pigs were used in this experimental model to simulate growing rod instrumentation technique. Cranially T12-L1 and caudally L4-L5 vertebrae were instrumented by pedicle screws bilaterally, while L2 and L3 were skipped. Distraction between pedicle screws was applied at index surgery. The rods were then lengthened twice in a month interval. All subjects were evaluated with lateral spinal X- ray preoperatively, postoperatively and at the final follow-up. The vertebral body heights of distracted segments (HD= L2 and L3) and control segments (HC= T9, T10 and T11) were measured. Average vertebral body heights and the percent increase in the vertebral body heights were compared among control segments (n=11) and distracted segments (n=8). Results Four subjects were lost during the immediate postoperative period. The preoperative vertebral body height was similar in two groups (HC:10.97mm, HD:11.27mm, p0.05). At the final follow-up, the average vertebral body height in distraction group was significantly higher than the control group (HC:16.92mm HD:18.56mm, p0.05). The percent increase in vertebral body height was higher in distracted segments but there was no statistically significant difference between the two groups (HC:54.1%, HD:64.4%, p0.05). Postoperative average vertebral body height in distraction group was significantly longer than preoperative measurements (HDpreop: 10.55mm, HDpostop: 17.49mm, p0.05). Conclusion The vertebral growth continues during growing rod instrumentation. Distraction forces might stimulate also apophyseal growth of axial skeleton. 3. Paper #3 Results of Three Classes of Surgical Treatment for Congenital Scoliosis due to Hemivertebrae: A Multicenter Retrospective Review Michael O'Brien, M.D., Peter Newton, M.D., Randy Betz, M.D., Harry Shufflebarger, M.D., Angel Macagno, M.D., Baron Lonner, M.D., Lynn Letko, M.D., Jurgen Harms, M.D., Alvin Crawford, M.D., Suken Shah, M.D., Paul Sponseller, M.D., Michelle Marks, PT MA Summary 42 patients with hemivertebrae (HV) and congenital scoliosis were compared based on one of three surgical treatments. HV resections with posterior instrumentation results in reduced surgical time, shorter fusions, less blood loss, and improved % correction but slightly higher rates of instrumentation and neurologic complications. Introduction We compare the outcomes of 3 surgical treatments for congenital deformities due to a focal hemivertbra (HV). Methods A retrospective multi-center database was compiled from 8 centers to evaluate patients treated surgically for congenital spinal deformity due to 1 or 2 level HV. The surgical treatment were: Group 1, fusion without correction (hemi-epiphysiodesis or in-situ fusion), Group 2, correction without HV resection (with or without anterior or posterior release) and posterior instrumentation, and Group 3, correction with HV resection (anterior and/or posterior) and posterior instrumentation. Results Forty-two patients, with two-year follow-up, were treated between 1991 and 2004. The congenital anomalies were: fully segmented, non incarcerated HV (n=32, 76.2%), incarcerated HV (n=1, 2.4%), and semi-segmented HV (n=9, 21.4%). The distribution of surgical treatments were: Group 1: n=10(24%), Group 2: n=9 (21%), Group 3: n=23 (55%). Pre-operative curve sizes were statistically different: Group 1, 37 and Group 3, 34 were significantly smaller than Group 2, 55 (p=0.04 and p</p>