Objective: Precise and reproducible control of wedge resection remains challenging in osteotomy correction for ankylosing spondylitis–related rigid kyphosis, and reports of robotic stereotactic execution beyond pedicle screw placement are limited. This technical note describes the operative workflow of robot-assisted stereotactic osteotomy (RASO), focusing on quantitative wedge planning and stereotactic execution feasibility.
Methods: The RASO technique and operative workflow are described. Patients with type II ankylosing spondylitis-related thoracolumbar deformity who underwent single-level three-column RASO between May and November 2023 were analyzed. Preoperative planning was performed using Surgimap wedge simulation with ratio-of-closure–based prediction, and stereotactic osteotomy trajectories were executed using the Mazor X Stealth Edition system. Perioperative parameters and immediate postoperative radiographic findings were descriptively assessed to evaluate the feasibility and reliability of the proposed operative workflow.
Results: This technique was successfully implemented in 15 patients. The mean operative duration was 304.2 ± 51.4 min, and the mean intraoperative blood loss was 486.7 ± 229.5 mL. Planning–execution concordance demonstrated acceptable agreement, with a maximal ratio-of-closure–related deviation of ≤ 5.18° and a mean difference of 0.2° between planned and achieved osteotomy Cobb angles. The mean thoracolumbar kyphosis (TLK) improved from 50.2° to 13.2°, the chin-brow vertical angle (CBVA) improved from 36.7° to 15.1°, the PT improved from 35.6° to 26.6°, and the sagittal vertical axis (SVA) improved from 207.6 to 93.7 mm. Three intraoperative durotomies occurred during the decompression phase; one patient developed delayed cerebrospinal fluid leakage. No neurological deficits, hardware failure, or mortality were observed. All patients achieved osseous fusion and demonstrated improvements in health-related quality of life measures.
Conclusions: This technical note demonstrates the technical feasibility and workflow reliability of robot-assisted stereotactic osteotomy for rigid ankylosing spondylitis–related thoracolumbar kyphotic deformity. Quantitative wedge planning can be reproducibly translated into robotic stereotactic intraoperative execution. Further studies are required to define the broader clinical role and potential applications of this technique.Trial Registration: Chinese Clinical Trial Registry: 2400090375.
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