A Modified Posterior Approach for Decompression of a Multiloculated Atlanto-axial Cyst With Myelopathy.

Abstract

Case report. To describe a modified posterior approach for decompression and excision of a multiloculated atlanto-axial cyst. Atlanto-axial cyst with myelopathy is rare. A direct decompression through anterior approach or an indirect decompression through posterior approach has been proposed. We report a rare multiloculated large C1-C2 cyst extending down to C3 body with myelopathy that created a dilemma in choice of approach. A modified posterior approach was adopted for decompression. A 72-year-old lady, known case of Rheumatoid arthritis, presented with cervical myelopathy which was rapidly progressive since 2 months being her to wheel chair bound. She had clumsiness of gait and bilateral grip weakness. Both upper and lower extremities had nonfunctional power (medical research council scale grade 2). Deep tendon reflexes were exaggerated. Sensation was reduced in trunk and both extremities. Magnetic resonance imaging and computed tomography scan showed a large multiloculated cyst compressing spinal cord. Here author used modified posterior approach from the right side to access the cyst. The C2 ganglion excision, vertebral artery isolation, and resection of the pars allowed an approach similar to transforaminal decompression in the lumbar spine. A large antero-lateral epidural part of the cyst was excised. The retro-dental cyst was decompressed by puncturing cyst. Biopsy confirmed a synovial cyst. The patient showed rapid neurological recovery after surgery. Postoperative magnetic resonance imaging at 3 months showed complete resolution of cyst. At 2-year follow-up, there was a complete neurological recovery with residual spasticity. A customized posterior approach allowed near total excision of a rare multiloculated large C1-2 cyst extending to the C3 body. This allowed visualisation anterior to the spinal cord without undue retraction that saved an additional anterior decompression. 5.