Development of a patient-specific surgical drill guide for pedicle screw fixation in the lower cervical spine using rapid three-dimensional prototyping

Abstract

The canine vertebral surgical stabilization is indicated as treatment of several neurological disorders. This technique is challenging and the complications are imminent. So far, little specific instrumentation for implant application has been developed, unlike human neurosurgery, in which guide and navigation systems were remarkably created. Our objective is to evaluate the fixation accuracy of pedicle screws in the lower cervical vertebrae of dogs, through a surgical drill guide (which will be made from a patient-specific 3D printed virtual vertebral model). In order to achieve this goal, seven canine cadavers will be submitted to computed tomography (CT), the resulting images of the C5, C6 and C7 cervical vertebrae (in DICOM format) will be exported to a three-dimensional (3D) reconstruction software, that will allow the creation of a surgical drilling guide, based on the ideal angles of the vertebrae. After the virtual creation, the model will be exported to 3D printing with biocompatible and autoclavable material. Finally, the guides will be applied into the corpses and the postoperative CT images will be sent to a program, to evaluate and compare the following aspects: the entry points; the transverse angle; and the sagittal angle of the perforations between the ideal and real screws. This study results can aid in the dissemination of the use of patient-specific surgical guides in the veterinary neurosurgery. In addition, it can also allow a quick, more precise and effective technique (alternative to conventional freehand technique or those performed with fluoroscopy). (AU)