Innovative One-Hole Split Endoscopy for Posterior Atlantoaxial Lateral Mass Joint Fusion: Technical Details and Preliminary Clinical Application

<sec><title>Background</title> Posterior atlantoaxial arthrodesis is a cornerstone of atlantoaxial instability or dislocation. Open surgery entails extensive soft-tissue dissection, with intraoperative blood loss and postoperative axial pain. Experience from other spinal procedures suggests that one-hole split endoscopy may address these limitations; however, evidence at the craniovertebral junction is lacking. </sec><sec><title>Surgical Technique</title> This study introduces an innovative, minimally invasive technique for atlantoaxial fusion: one-hole split endoscopy for posterior atlantoaxial lateral mass joint fusion. By delineating the anatomic layers, safety boundaries, and technical points, the technique enables endoscopic lateral mass joint arthrodesis and atlantoaxial screw fixation. </sec><sec><title>Clinical Application</title> A 12-year-old boy with diagnosed atlantoaxial instability and os odontoideum underwent the one-hole split endoscopy for posterior atlantoaxial lateral mass joint fusion. Early postoperative imaging confirmed anatomic reduction of the joint with stable fixation. At 3 months, computed tomography revealed continuous bony bridging across the lateral mass joint space, indicating early osseous fusion. </sec><sec><title>Conclusion</title> This study describes the first clinical application of posterior atlantoaxial lateral mass joint fusion using one-hole split endoscopy, demonstrating clinical feasibility and enhanced visualization and suggesting a potential role for endoscopic fusion at the craniovertebral junction. </sec><sec><title>Clinical Relevance</title> This technique offers an innovative, minimally invasive option for posterior atlantoaxial fusion and supports the broader application of endoscopic procedures at the craniovertebral junction. </sec><sec><title>Level of Evidence</title> 4. </sec>