Use of computed tomography for maxillary nerve block in the treatment of trigeminal neuralgia.

BACKGROUND AND OBJECTIVES: Maxillary nerve block has traditionally been performed by using external anatomic landmarks. However, the classic approach to the nerve may be confounded because of anatomic variability. We describe a technique for the block using the suprazygomatic route guided by computed tomography (CT). CASE REPORT: A 90-year-old woman had a 30-year history of episodic pain in her right maxillary region. We attempted to block the maxillary nerve with classic technique, but we could not identify the nerve by eliciting paresthesia. In addition, bleeding was noted after repeated attempts. To minimize complications and confirm the correct position of the needle tip, we planned the block with a suprazygomatic approach using CT guidance. The needle was inserted without paresthesia. The CT scan showed the needle tip was placed at the entrance of the pterygopalatine fossa and the distribution of contrast medium spread appropriately around the pterygopalatine fossa. After confirming the clinical effect and lack of complications of the block using the local anesthetic, 0.5 mL of 7% phenol was injected. This technique resulted in complete sensory loss in the area innervated by the maxillary nerve, and did so without complications.
CONCLUSIONS: A maxillary nerve block guided by a CT imaging is an alternative to classic techniques.