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Novel Technique for C1–2 Interlaminar Arthrodesis Utilizing a Modified Sonntag Loop-Suture Graft With Posterior C1–2 Fixation Robert M. Koffie, Alexandra M. Giantini Larsen, Benjamin L. Grannan, Muhamed Hadzipasic, Vijay Yanamadala, Laura Van Beaver, Ganesh M. Shankar, John H. Shin Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA Objective: Conventional techniques for atlantoaxial fixation and fusion typically pass cables or wires underneath C1 lamina to secure the bone graft between the posterior elements of C1–2, which leads to complications such as cerebrospinal fluid (CSF) leak and neurological injury. With the evolution of fixation hardware, we propose a novel C1–2 fixation technique that avoids the morbidity and complications associated with sublaminar cables and wires. Methods: This technique entails wedging and anchoring a structural iliac crest graft between C1 and C2 for interlaminar arthrodesis and securing it using a 0-Prolene suture at the time of C1 lateral mass and C2 pars interarticularis screw fixation. Results: We identified 32 patients who underwent surgery for atlantoaxial with our tech-nique. A 60% improvement in pain- related disability from preoperative baseline was dem-onstrated by Neck Disability Index (p < 0.001). There were no neurologic deficits. Compli-cations included 2 patients CSF leaks related to presenting trauma, 1 patient with surgical site infection, and 1 patient with transient dysphagia. The rate of radiographic atlantoaxial fusion was 96.8% at 6 months, with no evidence of instrumentation failure, graft dislodge-ment, or graft related complications. Conclusion: We demonstrate a novel technique for C1–2 arthrodesis that is a safe and effec-tive option for atlantoaxial fusion. Keywords: Arthrodesis, Atlantoaxial instability, Fusion, Interlaminar bone graft, Sublaminar INTRODUCTION Atlantoaxial instability due to cervical spine congenital mal- formations, inflammatory disease, benign and malignant neo- plasms, degeneration, and trauma is commonly encountered by spine surgeons. Instability in the cervical spine can lead to neck pain, cervical deformity, spinal cord injury, and disability. 1,2 Several surgical techniques for atlantoaxial fixation have been proposed over the years to treat patients with atlantoaxial insta- bility and innovative approaches continue to emerge. 3 Here, we report our technique that secures the bone graft at C1–2 in a safe and expedient manner, facilitating fusion while minimiz- ing complications associated with securing the bone graft. The earliest reported approach for treating atlantoaxial insta- bility was in 1910 when Mixter and Osgood 4 used stout braided silk to anchor the posterior arch of C1 to the spinous process of C2. Gallie 5 then expanded upon this approach in 1937 by using threaded steel wire in likewise fashion while adding an autolo- gous iliac bone graft secured by these wires within the posterior elements of C1 and C2. Brooks and Jenkins proposed a differ- ent approach by using sublaminar wires to secure bilateral iliac crest bone grafts, in an effort to promote more robust fusion. 6 This was followed by the Sonntag approach, which involves crimp- ing a sublaminar C1 wire to the notch in C2 process along with AUGUST 2021 | The Surgical Technologist | 351