Expanded Endoscopic Endonasal Approach and Odontoidectomy for Atlantoaxial Synovial Cyst

Area of Science:

• Neurosurgery
• Minimally Invasive Spine Surgery
• Cervical Spine Pathology

Background:

• Synovial cysts of the atlantoaxial joint (AAJ) are rare and can lead to spinal cord compression and cervical myelopathy.
• Surgical treatment of retro-odontoid lesions is complex due to anatomical challenges and proximity to vital structures.
• Traditional surgical approaches carry significant risks and morbidity.

Purpose of the Study:

• To report the successful treatment of an isolated AAJ synovial cyst using an endoscopic endonasal approach (EEA).
• To highlight technical refinements in EEA for optimal access to the retro-odontoid space.
• To evaluate the efficacy and safety of EEA as a minimally invasive alternative for retro-odontoid pathologies.

Main Methods:

• A case report of a 48-year-old female patient with a symptomatic AAJ synovial cyst.
• Surgical intervention involved an endoscopic endonasal odontoidectomy and lesion resection.
• Technical modifications included posterior septectomy and targeted odontoid drilling to enhance surgical access.
• The procedure was followed by posterior occipitocervical fusion.

Main Results:

• Complete resection of the AAJ synovial cyst and effective decompression of the spinal cord were achieved.
• Histopathology confirmed the diagnosis of a synovial cyst.
• The EEA facilitated ventral decompression while minimizing oropharyngeal trauma and avoiding dural violation.

Conclusions:

• The endoscopic endonasal approach is a viable and minimally invasive option for managing AAJ synovial cysts.
• Strategic modifications can overcome the limitations of the endonasal corridor, improving surgical outcomes.
• EEA offers a reduced morbidity alternative to transoral and posterior transdural approaches for select retro-odontoid pathologies.