Preoperative 3D surgical planning using Mimics significantly decreased the rate of internal fixation in cervical dumbbell tumor resection and improved the postoperative outcome: a single-center retrospective study

Compare preoperative Mimics 3D planning and conventional planning on internal fixation and perioperative outcomes in cervical dumbbell tumor resection.

We retrospectively analyzed 40 patients with cervical dumbbell tumors undergoing posterior resection (2017–2025). Subjects were split into two groups by preoperative planning: Mimics 3D (n = 20) or conventional (n = 20). The primary outcome was internal fixation rate. Secondary outcomes were defined as: operation time (minutes from incision to wound closure), estimated intraoperative blood loss (measured in milliliters), length of postoperative hospital stay (days from surgery to discharge), functional improvement (assessed using Japanese Orthopaedic Association [JOA] score and American Spinal Injury Association [ASIA] scale), and the rate of postoperative complications. Subgroup analyses were performed by tumor location (C4-C7, C2-C4&C7-T1).

Groups had similar baseline characteristics. In the Mimics group, surgeons used internal fixation in 45.0% of cases, compared with 95.0% in the control group. The absolute risk reduction was 50.0% (*p*<0.001). This trend held across spine regions: for C4-C7, surgeons used fixation in 33.3% (Mimics) vs. 87.5% (control) (*p*=0.015); for C2-C4 & C7-T1, they used it in 54.5% (Mimics) vs. 100.0% (control) (*p*=0.005; *p* for interaction = 0.196). Surgeons working with 3D planning operated more quickly (187 ± 22.0 min vs. 222 ± 32.1 min, *p*<0.001) and discharged patients sooner (5.5 ± 1.64 days vs. 8.5 ± 1.93 days, *p*<0.001). Patients in the Mimics group improved more in JOA scores (+ 3.70 ± 0.85 vs. +2.05 ± 0.82, *p*<0.001) and experienced fewer complications (15.0% vs. 50.0%, *p*=0.034).

Preoperative Mimics 3D planning reduces the need for internal fixation and enhances postoperative outcomes, underscoring its essential role in the management of cervical dumbbell tumors.