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Angle-assisted instrumentation of the spine

Research Project
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01.08.2013
 - 31.12.2014

Successful implantation of screws in the spine depends on choosing correct starting points and insertion angles. Although modern intraoperative navigation facilitates instrumentation of the spine, the equipment is costly and availability is limited. Intraoperative fluoroscopy is the most widely available tool to guide implantation of screws but it usually shows only one plane at a time and repetitive imaging may be required which raises concerns of radiation exposure. Thus the surgeon's understanding of spinal anatomy and the familiarity with the technique of implanting screws "bridge" the missing information of monoplanar fluoroscopy. For instance, a laterally positioned fluoroscope will display the depth of the screw and if it is oriented more towards the head or feet (sagittal angulation), but not the latero-medial (axial) angulation. To assist the surgeon in adjusting the screw into the correct orientation, we have developed a prototype device (called AngleGuide ) which measures angular tilt in the sagittal and axial plane. The technology is based on a microelectromechanic system as it is used in smartphones to orient the screen according to how the user holds the device. The AngleGuide can be used to align the surgical instruments to predefined angles that were measured on preoperative computed tomography (CT). We hypothesize that the AngleGuide can be used to maintain a safe trajectory when implanting screws in the spine while minimizing radiation exposure to the patient and surgical staff. We will implant more than 250 screws in seven cadaveric human thoracic and lumbar spines and compare accuracy of AngleGuide -assisted implantation of screws versus accuracy of non- AngleGuide -assisted implantation. A preoperative CT scan will be used for planning of the surgery and a postoperative CT scan will be used for analysis of the screw trajectories. Given successful implementation of the AngleGuide prototype, this technology could be developed for clinical use and become an affordable tool to ensure proper implantation of screws with minimal radiation exposure to the patient and staff.

Publications

Jost, Gregory F. et al. (2016) ‘A novel approach to navigated implantation of S2 alar iliac screws using inertial measurement units’, Journal of Neurosurgery. Spine, 24(3), pp. 447–453. Available at: https://doi.org/10.3171/2015.6.spine1594.

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Walti, Jonas, Jost, Gregory and Cattin, Philippe C. (2014) ‘A new cost-effective approach to pedicular screw placement’, in Linte, CA; Yaniv, Z; Fallavollita, P; Abolmaesumi, P; Holmes, DR (ed.) Augmented Environments for Computer-Assisted Interventions : 9th International Workshop, AE-CAI 2014, held in conjunction with MICCAI 2014, Boston, MA, USA, September 14, 2014 ; Proceedings. Heidelberg: Springer (Augmented Environments for Computer-Assisted Interventions : 9th International Workshop, AE-CAI 2014, held in conjunction with MICCAI 2014, Boston, MA, USA, September 14, 2014 ; Proceedings), p. S. 90–97. Available at: https://doi.org/10.1007/978-3-319-10437-9_10.

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Jost, Gregory F, Bisson, Erica F and Schmidt, Meic H (2013) ‘iPod Touch-Assisted Instrumentation of the Spine: A Technical Report’, Neurosurgery, 73(2 Suppl Operative), p. ons233–7; discussion ons237. Available at: https://doi.org/10.1227/neu.0000000000000023.

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Members (2)

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Philippe Claude Cattin

Principal Investigator
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Magdalena Müller-Gerbl

Co-Investigator