Suboccipital neuralgia after C1 pedicle screw insertion: do we neglect atlantooccipital joint violation? - Case report and literature review

Abstract

Background: Occipital neuralgia is one of the postoperative complications of C1 lateral mass screw insertion, which was deemed to be related with the C2 nerve root dysfunction.

Case presentation: A 52-year-old female patient presented with gradually progressive numbness and weakness in her extremities for 6 months. X-ray and computed tomography (CT) scan revealed obvious anterior atlantoaxial dislocation (ADD), which was reducible on extensive view. Atlantoaxial pedicle screw fixation and bone graft was performed. Immediately after the operation, the neurological symptom significantly improved. The patient complained of restricted cervical rotation and suboccipital neuralgia which was exacerbated by rotation with an intensity of 7 on a visual analog scale (VAS) ranging from 0 to 10 at postoperative day 5. While a satisfactory reduction was detected in the postoperative CT, violation of the left atlantooccipital joint was observed in the left C1 screw. Nimesulide (daily dosage of 0.2 g) and bracing were recommended immediately. At the 2 month follow-up, both the neurological improvement and reduction were maintained. The VAS of suboccipital neuralgia is 3 and decreased to 1 at 6 months postoperative. Bony fusion of the left atlantooccipital joint was confirmed by CT scan at 6 months postoperative. The patient complained that the suboccipital neuralgia was tolerable without the assistance of braces or medications for pain. At the 18 month follow-up, only stiffness of head flexion and rotation was observed without suboccipital neuralgia.

Conclusion: Suboccipital neuralgia after atlantooccipital joint violation of C1 pedicle screw placement most likely results from C1 nerve root irritation. As the corresponding dermatome differs from the distributing region and aggravated factor of C2 nerve root dysfunction, neuralgia due to C1 irritation was only localized at suboccipital region and exacerbated by rotation.

Keywords: Atlantoaxial fixation; Atlantoaxial instability; Atlas screw; Complications; Lateral mass; Occipital neuralgia; Pedicle.

Fig. 1

X-ray revealed obvious anterior atlantoaxial dislocation (left), which was reducible on extension view (right)

Fig. 2

Computed tomography (CT) scan revealed obvious anterior atlantoaxial dislocation

Fig. 3

The left side of the posterior arch was revealed as the site of defect on CT 3-dimensional imaging

Fig. 4

While a satisfactory reduction was detected in the postoperative CT, violation of the left atlantooccipital joint was observed in the left C1 screw (arrow)

Fig. 5

Bony fusion of the left atlantooccipital joint was confirmed by CT scan at 6 months postoperativ

Fig. 6

The suboccipital nerve is the dorsal primary ramus of the first cervical nerve, which was highlighted by red color