Background: Traditionally, the workflow for cortical bone trajectory (CBT) screws has included tapping either line-to-line or under tapping by 1 mm. To our knowledge, no reports describe a ...non-tapping, 2-step workflow for CBT screw placement. We sought to compare the safety profile and time savings, if any, in this no-tap (2-step) versus tap (3-step) workflow. Methods: Patients undergoing robotic-assisted (RA) 1- to 3-level posterior spine fusion with CBT screws for degenerative conditions were identified. Patients were separated into either no-tap or tap workflow. Numbers of total screws, screwr-elated complications, screws malpositioned, aborted or converted, other complications, estimated blood loss (EBL), operating room (OR) time, robotic time and return to OR were analyzed. Results: We identified 179 RA-CBT patients with 91 patients undergoing 2-step (458 screws) and 88 undergoing 3-step (466 screws) workflow. There was no difference in age, sex, body mass index, revisions status, smoking, American Society of Anesthesiologists (ASA) score, approach (posterior only v. anterior-posterior), number of levels fused or diagnosis between the cohorts. Total robotic time was decreased from 30.3 (tap) to 26.7 (no tap) minutes (p = 0.05), while OR time (181.4 tap v. 169.9 no tap min) was decreased as well but not significantly (p = 0.24). No patient in either cohort was returned to OR for malpositioned screws. There was no difference in malpositioned screws identified intraoperatively (6 v. 10, p = 0.43), screws converted to freehand (3 v. 3, p = 0.69) or screws abandoned (2 v. 3, p = 1.00). No pedicle fracture or fixation failure was identified in the no-tap cohort with 1 in the tapping cohort (p = 1.00). Conclusion: The no-tap (2-step) screw insertion workflow for RA-CBT reduced robotic time without increased complications. In both cohorts, no patients were returned to the OR for malpositioned screws and no pedicle fractures or fixation-related complications were identified in the no-tap (2-step) workflow. The no-tap workflow is safe and improves efficiency in RA-CBT screw insertion.
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