Template guided versus freehand rod bending in spinal deformity surgery: a feasibility study

Spinal deformity correction relies on osteotomies and precisely contoured rods, which are critical for restoring sagittal alignment. Inaccurate rod bending may compromise alignment and increase the risk of junctional failure. This feasibility study compares the accuracy of template-guided versus freehand rod contouring in a simulated environment. Using SurgiMap^® software, 12 double-curved rods were designed from full-spine radiographs. Six surgeons from a tertiary spine centre bent rods freehand or using 2D paper templates. Two rod specifications were tested: ⌀4.0 mm stainless steel rods for cervicothoracic and ⌀6.0 mm cobalt-chromium rods for thoracolumbar models, representing the mechanical extremes of commonly used spinal implant configurations. Digitized rod contour angles (RCAs) were compared with planned contours using tangent-vector analysis. Template-guided bending significantly improved accuracy (mean RCA difference: 2.6° ± 1.3°, p < 0.01) and required fewer bends (4.1 ± 1.3, p < 0.01), without a significant time increase (p = 0.11). Subgroup analysis showed significant improvement only in less experienced surgeons. In conclusion, template-based rod bending improved sagittal contouring accuracy and efficiency in a simulated environment, with the greatest benefit for less experienced surgeons. Further clinical studies are necessary to confirm these results.