2026 Poster Presentations
P073: ENDOSCOPIC ENDONASAL ODONTOIDECTOMY FOR ATLANTOAXIAL SYNOVIAL CYST
Paarth Patel, BSA; Jonathan Espinosa, MD; Thomas Tyler Patterson, MD; Erin Lopez, MD; Cristian Gragnaniello, MD, PhD; UT Health San Antonio
Introduction: Synovial cysts at the atlantoaxial joint (AAJ) are a rare pathological entity that can cause spinal cord compression, necessitating surgical intervention. Retro-odontoid lesions present significant surgical challenges due to the complex anatomy and proximity to critical structures. Traditional approaches, such as the transoral (TO) and posterior transdural (TD) routes, are associated with morbidity, including pharyngeal palsy or cerebrospinal fluid leakage. The endoscopic endonasal approach (EEA) offers a minimally invasive alternative, providing direct access to the retro-odontoid space while reducing complications. This report presents the first known case of an AAJ synovial cyst resected solely via an EEA.
Clinical Presentation: A 48-year-old female with a history of prior C4 corpectomy and C3-C7 anterior fusion presented with worsening neck pain, cervicalgia, and cervical myelopathy due to a retro-odontoid cystic lesion with cord compression (Figure 1). She underwent an anterior removal of the lesion with an EEA approach and a posterior cervical fusion. A posterior septectomy optimized access, and the odontoid process was drilled down to expose the retro-odontoid space (Figure 2). The lesion was carefully excised, adequately decompressing the spinal cord; subsequent pathology was consistent with synovial cyst.
Figure 1. Preoperative sagittal (A) and axial (B) T2-weighted MRI depicting retro-odontoid synovial cyst (red arrow) compressing the cervical spinal cord.
Figure 2. Endoscope view of retro-odontoid space before (A) and after (B) excision of the synovial cyst. The clivus (C), drilled portions of the C1 anterior arch (C1), synovial cyst (SC), and anterior dura (D) after synovial cyst excision are all labeled.
Conclusion: The EEA minimizes morbidity by preserving oral pharyngeal structures and avoiding dural violations required in posterior transdural approaches. Optimizations to increase surgical maneuverability and the use of angled endoscopes can decrease the limitations found in an EEA to this area. By enabling safe and effective decompression while minimizing trauma to pharyngeal and oral tissues, the EEA represents a viable, minimally invasive alternative for addressing AAJ synovial cysts and other retro-odontoid pathology.