Introduction: Spinal pedicle screw placement remains a challenge in terms of accuracy and complications rate. Many of the techniques available today are highly expensive and therefore inaccessible in developing countries. Thus, the need for solutions combining precision and low costs in spine-surgery became urgent. Combining computed tomography, three-dimensional reconstruction and rapid prototyping has enabled the production of surgical guides that indicate the exact path for pedicle screw placement as defined by preoperative planning. The use of surgical guides (technique routinely used in dentistry) can optimize spine surgery as a whole by reducing costs, operative time and radiation exposure without putting aside accuracy.

Methods: 10 porcine lumbar spines were acquired and submitted to Volumetric CT acquisitions. Three-dimensional preoperative planning was performed using Eximius navigation software (ARTIS Technology, Brasilia, Brazil). Surgical guides were developed based on the preoperative planning and produced using rapid prototyping by layer deposition. Two neurosurgeons were chosen to simulate the pedicle screw placements. Operative time was regarded as the time required to implant a screw after completion of the dissection. Pedicle screw positioning was assessed using 3D MPR reconstruction in post-op CTs. Screw placement was classified as correct (graded 0 or 1) or incorrect (graded 2 or 3) based on the Youkilis et al. (2010) method.

Results: Out of 74 screws placed, 82,4% were correctly placed (78,4% grade 0 and 4% grade 1). It must be emphasized that most misplacements occurred in just two specimens (specimens 6 and 7) where half of the screws were misplaced. It remains the suspicion that a mistake has occurred. Average time for screw insertion was 60,1 seconds.

Conclusions: Overall, this study suggests that placement accuracy using surgical guides is comparable to preexisting techniques and could require a shorter screw insertion time. Further research is certainly needed to validate and compare this hypothesis.

Patient Care: We hope to improve patient care by providing a new alternative for spine surgery or at least provide a groundwork for future approaches

Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the importance of new techniques of spine arthrodesis in developing countries 2) Discuss the interchange between new engineering technologies and neurosurgery to improve patient care 3) Identify prototyped guides as a possible new technique in spine surgery in the upcoming years

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