Ahmed Hammad1, André Wirries1, Johanna Eberl1, Florian Geiger2,3. 1. Spine and Scoliosis Center, Hessing Foundation, Augsburg, Germany. 2. Spine and Scoliosis Center, Hessing Foundation, Augsburg, Germany. florian.geiger@hessing-stiftung.de. 3. Spine Surgery Department, Orthopaedic University Hospital Friedrichsheim, Frankfurt, Germany. florian.geiger@hessing-stiftung.de.
Abstract
PURPOSE: We compared two techniques for thoracic apical derotation; one using conventional reduction screws (Single-Innie-SI) and one requiring special derotation screws that can be converted to monoaxial screws to enhance dorotation (Dual-Innie-DI) for coronal and sagittal correction and. METHODS: A total of 200 patients with thoracic AIS have been included. In the SI-Group (n = 127) the convex rod was applied first. Vertebral derotation was done by translation to the concave rod with the convex rod being in place and center of rotation (COR). In the DI-Group (n = 73) correction started with translation on the concave side as well but now followed by derotation around the concave rod using the DI-mechanism. RESULTS: The mean rotation according to Raimondi and coronal correction was not sig. affected (72 (± 12) % in the SI-Group versus 68 (± 15) % in the DI-Group), even when flexibility was respected (Cincinnati Correction Index CCI was 2.9 (± 4.9) versus 3.5 (± 4.4). (p < 0.01). The gain of kyphosis was sig greater (2.7°) in the SI-group, but not clinical relevant. CONCLUSION: The use of DI screws for apical derotation did not provide an advantage for coronal correction or derotation in thoracic curves. Presumably after translation is performed in the DI-group, there was too much tension and friction in the construct impeding further derotation. Simultaneous translation and derotation in the SI-group, with the convex rod being the COR, yielded similar correction with better kyphosis and was faster and more economic.
PURPOSE: We compared two techniques for thoracic apical derotation; one using conventional reduction screws (Single-Innie-SI) and one requiring special derotation screws that can be converted to monoaxial screws to enhance dorotation (Dual-Innie-DI) for coronal and sagittal correction and. METHODS: A total of 200 patients with thoracic AIS have been included. In the SI-Group (n = 127) the convex rod was applied first. Vertebral derotation was done by translation to the concave rod with the convex rod being in place and center of rotation (COR). In the DI-Group (n = 73) correction started with translation on the concave side as well but now followed by derotation around the concave rod using the DI-mechanism. RESULTS: The mean rotation according to Raimondi and coronal correction was not sig. affected (72 (± 12) % in the SI-Group versus 68 (± 15) % in the DI-Group), even when flexibility was respected (Cincinnati Correction Index CCI was 2.9 (± 4.9) versus 3.5 (± 4.4). (p < 0.01). The gain of kyphosis was sig greater (2.7°) in the SI-group, but not clinical relevant. CONCLUSION: The use of DI screws for apical derotation did not provide an advantage for coronal correction or derotation in thoracic curves. Presumably after translation is performed in the DI-group, there was too much tension and friction in the construct impeding further derotation. Simultaneous translation and derotation in the SI-group, with the convex rod being the COR, yielded similar correction with better kyphosis and was faster and more economic.
Authors: Aliasgar Dalal; Vidyadhar V Upasani; Tracey P Bastrom; Burt Yaszay; Suken A Shah; Harry L Shufflebarger; Peter O Newton Journal: J Spinal Disord Tech Date: 2011-06
Authors: Mario Di Silvestre; Francesco Lolli; Georgios Bakaloudis; Elena Maredi; Francesco Vommaro; Francesca Pastorelli Journal: Eur Spine J Date: 2012-08-07 Impact factor: 3.134