Development and Clinical Feasibility of a Computer-Assisted Shape Design and Bending System for Spinal Fixation Rods

BACKGROUND Spinal pedicle screw-rod fixation is widely used, but manual rod bending is time-consuming and prone to contour inconsistencies. Although computer-assisted technologies have been explored, existing systems remain limited by cost, complexity, and insufficient precision. This study evaluated a novel computer-assisted rod design and bending system, with the goal of testing whether computer-assisted rod bending reduces bending plus installation time vs manual bending in unilateral paired cases and to evaluate safety, feasibility, and rod-screw fitting accuracy. MATERIAL AND METHODS A prospective trial enrolled 26 patients (18-75 years) undergoing spinal pedicle screw-rod fixation (≥4 segments) for fractures or degenerative diseases. Twenty patients received unilateral computer-assisted bending (contralateral manual for comparison) and 6 received bilateral assisted bending. The primary outcome was bending plus installation time; secondary outcomes included complications and fitting accuracy. Wilcoxon signed-rank test was used (P<0.05). RESULTS No instrument-related complications were observed (n=26; median age 60.5 years). For 20 unilateral cases, computer-assisted bending (183.3±70.8 seconds) was significantly shorter than manual bending (236.1±119.1 s; mean reduction 52.75 seconds, P=0.017). Subgroup analyses indicated signals of greater time savings in more than 4 segments (93.9 seconds, P=0.039) and BMI of 25 kg/m2 or higher (95.3 seconds, P=0.005), although these were exploratory and not adjusted for multiplicity. CONCLUSIONS The computer-assisted system reduced bending plus installation time vs manual bending, with no instrument-related complications. Subgroup findings were exploratory and require further validation.