The Best of Both Worlds: Combining Freehand and Mobile Intraoperative CT-Navigated Instrumentation in Pediatric Deformity Corrections—A Retrospective Case Series of 31 Consecutive Patients

Background/Objectives: Image guidance improves pedicle screw accuracy in pediatric spinal deformity yet may increase operative time and radiation. We evaluated the feasibility and safety of a single-scan hybrid strategy using freehand screws below the deformity apex and CT-navigated screws at apical and upper thoracic levels. Methods: We retrospectively reviewed 31 patients (24 adolescent idiopathic and 7 syndromic/neuromuscular scoliosis) undergoing posterior instrumentation with intraoperative neuromonitoring (age, 16 ± 5 years; follow-up, 19 ± 10 months). Freehand screws were placed below the apex, followed by one CT to verify them and register navigation; apical/upper thoracic screws were navigated, with alignment assessed by biplanar fluoroscopy. The primary outcome was safety; secondary outcomes were freehand screw accuracy (Gertzbein–Robbins classification), radiation dose, coronal correction, and SRS-22r scores. Results: No neurological or implant-related complications occurred. Of 278 freehand screws, 95.0% were grade A or B; four unacceptable screws (1.4%) were immediately revised with navigation. One of 282 navigated screws (0.4%) was revised after detection on a second intraoperative CT obtained for neuromonitoring changes. Effective dose was 3.80 ± 1.66 mSv per patient. Coronal correction was maintained, and the mean SRS-22r score was 4.2 ± 1.0. Conclusions: The workflow was feasible and safe, with a per-patient radiation dose corresponding to a single scan—about half that of two-scan fully navigated workflows—and high freehand accuracy on intraoperative CT. However, navigated screw accuracy may be overestimated because definitive assessment used fluoroscopy rather than postoperative CT, and the uncontrolled design does not allow conclusions on operative time, warranting prospective comparative studies.