Enhanced cephalomedullary nail lag screw placement and intraoperative tip-apex distance measurement with a novel computer assisted surgery system.

OBJECTIVE: The goal of this study was to evaluate the ability of a novel computer assisted surgery system to guide ideal placement of a lag screw during cephalomedullary nailing and then accurately measure the tip-apex distance (TAD) measurement intraoperatively.

DESIGN: Retrospective case review.

SETTING: Level II trauma hospital.

PATIENTS: The initial 98 consecutive clinical cases treated with a cephalomedullary nail in conjunction with a novel computer assisted surgery system were retrospectively reviewed.

INTERVENTION: A novel computer assisted surgery system was utilized to enhance lag screw placement during cephalomedullary nailing procedures. The computer assisted surgery system calculates the TAD intraoperatively after final lag screw placement.

MAIN OUTCOME MEASURES: The ideal TAD was considered to be within a range of 5mm-20mm. The ability of the computer assisted surgery system (CASS) to assist in placement of a lag screw within the ideal TAD was evaluated. Intraoperative TAD measurements provided by the computer assisted surgery system were then compared to standard postoperative TAD measurements on PACS (picture archiving and communication system) images to determine whether these measurements are equivalent.

RESULTS: 79 cases (80.6%) were available with complete information for a retrospective review. All cases had CASS TAD and PACS TAD measurements >5mm and<20mm. In addition, no significant difference could be detected between the intraoperative CASS TAD and the postoperative PACS TAD (p=0.374, Wilcoxon Test; p=0.174, paired T-Test). A cut-out rate of 0% was observed in all patients who were treated with CASS in this case series (95% CI: 0 - 3.01%).

CONCLUSIONS: The novel computer assisted surgery system tested here is an effective and reliable adjunct that can be utilized for optimal lag screw placement in cephalomedullary nailing procedures. The computer assisted surgery system provides an accurate intraoperative TAD measurement that is equivalent to the standard postoperative measurement utilizing PACS images.

LEVEL OF EVIDENCE: Therapeutic Level IV.