Additive technologies in surgical treatment of spinal deformities

Abstract

Purpose of study: to summarize the experience in three-dimensional biomodeling and custom made metal constructions for surgical treatment of spinal deformities of different localization and etiology, evaluate its advantages, potentialities and efficacy. Patients and methods. During the period from 2011 to 2018 three-dimensional (3D) custom-made spinal models were used in 52 patients with different spinal deformities: congenital multilevel spinal deformity (n=20), upper cervical spine deformities (n=12), III-IV degree of spondylolisthesis (n=10), neurogenic scoliosis (n=8), neurofibromatosis (n=2). 3D models were created in scale 1:1 by stereolithographic technique on the basis of computer model designed by spiral CT results. In all cases 3D models were used for preoperative planning including the intended deformity correction, decompression and spine fixation. In 26 cases 3D spinal models were used to manufacture the custom made metal constructions for the deformity correction and spine fixation: plates for the upper cervical spine anterior fixation, cervicothoracic junction, plates and cages for lumbosacral fixation, and implants for spinopelvic fixation. Results. In all cases the use of spine bio models enabled to achieve important additional information at preoperative planning and intraoperatively. Long-term follow up made up 3 years. After neural structures decompression and deformity correction good clinical and roentgenologic results were observed in all patients. Use of custom made implants ensured stable spine fixation in all cases with the exception of 3 patients in whom the implants were removed due to infectious complication (n=1) and poor postoperative wood healing. Conclusion. In deformities of different etiology the full-scale spine models provide better assessment of the deformity pattern and preoperative planning. 3D models and computer modeling make possible the manufacture of individual metal constructions for spine fixation that is especially topical in severe deformities.