Retro-Odontoid Intradural Synovial Cyst Decompression via Endoscopic-Assisted Far-Lateral Approach C1-C2 Hemilaminectomy Without Fusion: The Use of Intracranial Denticulate Ligament as Intraoperative Landmark

Abstract

Purely intradural retro-odontoid synovial cysts are rarely reported in neurosurgical literature, particularly in the absence of associated bony erosions. We present the case of a 57-year-old Native American male with a retro-odontoid synovial cyst and a history of chronic refractory neck pain that was adequately decompressed via an endoscopic-assisted far-lateral approach using a C1-2 hemilaminectomy, obviating the vertebral artery (VA) transposition, bony instability, and the need for instrumented bony fusion. The patient presented to our clinic with several months of refractory nuchal and cervical spine pain and crepitation affecting his activities of daily living (ADL). MRI findings revealed an intradural cyst at the level of C2 behind the odontoid process impinging on the medulla and causing early VA displacement. Both stereotactic neuronavigation and microsurgical visualization aided in the manipulation of the endoscope and attaining the caudocranial working trajectory. The patient remained neurologically non-lateralizing postoperatively, similar to his preoperative status. This article highlights a less invasive surgical exposure with an endoscopeassisted caudocranial trajectory obtained by a limited unilateral hemilaminectomy to achieve the desired outcome.

Management of rare atlantoaxial synovial cyst case with extension to the cerebellopontine angle: illustrative case

“…Forceful resection could lead to significant or permanent neurological complications given the proximity to critical structures. 13,14 Fortunately, in cases in which complete resection was not possible, significant improvement has been reported with partial resection/decompression and a low frequency of recurrence. 5,9,13 For our case, retromastoid craniectomy provided optimal exposure of the cyst.…”

“…Of 43 articles found on the topic from 1988 to 2023, only 30 cases were relevant to the atlantoaxial/atlantooccipital junction and only 13 of these cases were treated with craniotomy/craniectomy and/or involved cranial nerve palsy (Table 1). [2][3][4][5][6][7][8][9][10][11][12][13][14] Articles were excluded if pathology was found to be anything other than synovial cyst, if the cyst was at a subaxial cervical level, or if either full text was unavailable or the abstract did not provide sufficient information for the literature review.…”

Full-endoscopy with intraoperative O-arm navigation for cervicothoracic gas-containing hemorrhagic synovial cyst: A case report

“…In general, resection of the synovial cyst was using open or microsurgical surgery of hemilaminectomy or laminectomy with or without additional fusion. The majority of synovial cysts removal reported in the literature focused on the lumbar or cervicothoracic spine level [21] , [22] , [23] , [24] , [25] . As previous literature reports about the lumbar synovial cysts removal, the posterior endoscopic approach reduces the muscle denervation and decreases the risk of postoperative hematoma.…”

Atlantoaxial Intradural Synovial Cyst Mimicking an Extradural Lesion Adjacent to a Retro-odontoid Pseudotumor: A Case Report

“…To the best of our knowledge, only 13 cases of intradural synovial cysts or ganglion cysts in the spinal canal have been reported previously (Table 1). [8][9][10][11][12][13][14][15][16][17][18] Among these 13 cases, two were located at the lower lumber spine, whereas the other 11 occurred at the craniovertebral junction (CVJ). None of the previous literatures noted this high frequency of dural penetration at the CVJ.…”

“…Several case reports have been published on "intradural synovial cysts" (IDSCs). [8][9][10][11][12][13][14][15][16][17][18][19] A review of these reports showed that dural penetration of the extradural cyst most frequently occurs at the craniovertebral junction. Neurological symptoms had been caused by direct compression of the spinal cord, brain stem, or hypoglossal nerve.…”