High Cervical Lateral Approach to Safely Remove the Cystic Retro-odontoid Pseudotumor: Technical Note

Abstract

Surgery for neoplastic or vascular lesions at the craniovertebral junction remains one of the major challenges for neurosurgeons, because of issues such as the complex functional anatomy and vascular structures. We present three cases in which the high cervical lateral approach was used to safely remove the cystic retro-odontoid pseudotumor, not associated with rheumatoid arthritis, severely compressing the spinal cord. The mean age of patients was 74.7 years (range, 73-77 years). Neurological condition was assessed based on the neurosurgical cervical spine scale. A high cervical lateral approach was applied to remove the pseudotumor safely. Mean duration of follow-up after surgery was 21.3 months (range, 18-24 months). Mean recovery rate was 77.8%. All patients showed acceptable or satisfactory functional recovery, although one patient (Case 2) developed mild paralysis of the facial and spinal accessory nerve on the surgical approach side, but that completely recovered within about 1 month after surgery. Postoperative assessment at the recent follow-up suggested no significant aggravation of neck movement. This technical note suggests that the high cervical lateral approach can be considered as a surgical option for cystic retro-odontoid pseudotumor, not associated with rheumatoid arthritis, severely compressing the spinal cord. Safe management of the vertebral artery is one of the key considerations.

Keywords: atlantoaxial instability; high cervical lateral approach; retro-odontoid pseudotumor; spinal accessory nerve; vertebral artery.

Fig. 1

Surgical technique for the high cervical lateral approach. (A) Patient position. (B) Retroauricular curved skin incision. Please note the imaginary point of the transverse process of C1 (X). (C and D) Schematic drawings showing the surgical steps for minimal but sufficient exposure of the lateral part of the high cervical spine. The vertebral artery is located within the suboccipital triangle. Please note the transverse process of C1 (*).

Fig. 2

Intraoperative photographs showing the removal of cystic retro-odontoid pseudotumor compressing the spinal cord severely at C2. Intraoperative photographs (B–D) correspond to the boxed area in the spine model (A). (B) The lateral part of C1 and C2 laminae was resected to expose the cystic retro-odontoid pseudotumor in the ventral extradural area. (C) The cystic retro-odontoid pseudotumor was removed piece-by-piece. (D) Satisfactory decompression of the dural tube was obtained.

Fig. 3

Illustrative case (Case 1). (A and B) T2-weighted MR images before surgery showing the cystic retro-odontoid pseudotumor compressing the spinal cord severely at C2. Please note the paramedian location of cystic retro-odontoid pseudotumor. (C) T2-weighted MR images early after surgery showing the satisfactory decompression. (D) Axial CT images early after surgery showing the partial laminectomy of C1. Please note the approach direction (white arrow). (E and F) T2-weighted MR images 2 years after surgery showing no recurrence.