Extensive Axis Laminectomy and Atlantoaxial Stabilization for an Axial Intraspinal Extradural Ganglion Cyst in a Dog

Abstract We report the case of a 10-year-old male Pomeranian with an axial intraspinal extradural ganglion cyst who underwent extensive axis laminectomy, ganglion cyst excision, and atlantoaxial stabilization. The dog was examined due to acutely deteriorated tetraparesis. Upon neurological examination, the C1 to C5 segment was localized as the presumed impaired spinal cord. Magnetic resonance imaging (MRI) revealed a circumferential donut-like cystic lesion in the central axis of the epidural space. Axial hemilaminectomy was performed on the right side; however, the cyst was torn. A histopathological examination could not be performed. A significant initial improvement in clinical signs was followed by recurrence of the cystic lesions. During the second extensive laminectomy of the axis, partial ganglion cyst excision with atlantoaxial stabilization was performed. An intraspinal ganglion cyst was diagnosed based on MRI findings, the mucin-like cyst content, gross appearance, and histopathological examination results. The postoperative functional recovery was remarkable. At 25 months postoperatively, no neurological abnormalities were observed; absence of the ganglion cyst was confirmed on MRI. Surgical decompression involving extensive laminectomy, partial ganglion cyst excision, and atlantoaxial stabilization was successful in treating the extradural ganglion cyst. The clinical improvement was prompt; the long-term functional outcomes were satisfactory.