Pre-Operative Planning in Complex Deformities and Use of Patient-Specific UNiD™ Instrumentation

Study Design: Review of current literature and authors experience. Objective: Pre-operative planning is an integral part of complex spine surgery. With the advent of computer-assisted planning, multiple surgical plans can be evaluated utilizing alignment parameters, and the best plan for individual patients selected. However, the ability to evaluate and measure surgical correction goals intraoperatively are still limited. The use of patient-specific UNiD rods, created based on pre-operative plans, provided an initial tool for implementation of pre-operative plans in the operative setting. Methods: A literature review for the use of patient-specific UNiD rods in thoracolumbar spine complex surgery was performed. The articles were selected and reviewed for the initial experience/outcomes of these techniques. Further, the initial experience of the authors at The University of Colorado is described. Results: The use of UNiD patient-specific rods, in combination with pre-operative planning has been shown to provide a higher rate of patients with spinopelvic alignment parameters within currently accepted ranges. This includes improvement of sagittal vertical axis (SVA) < 50 mm and pelvic incidence (PI)-lumbar lordosis (LL) = +/- 10 degrees. Multiple authors have shown improvement in pelvic tilt to age adjusted values but note continued difficulties in obtaining correction goals. Conclusions: The use of pre-operative planning software and UNiD patient-specific rods has been shown to improve surgeon's ability to achieve spinopelvic alignment parameters, specifically SVA and PI-LL, along with other possible benefits. Further research is needed regarding long-term value of the technology.