Ultrasound guided percutaneous radiofrequency trigeminal rhizotomy
Blockade of the Gasserian ganglion or its branches is an effective analgesic procedure for trigeminal neuralgia, traditionally performed using fluoroscopy or CT imaging. Ultrasonography allows point of care and real-time visualization of needle placement within the surrounding anatomical structures. The use of ultrasonography with pulsed radiofrequency therapy for trigeminal neuralgia has been reported by Nader et al. 1).
The lateral pterygoid muscle and maxillary artery are key anatomical landmarks for ultrasound-guided trigeminal nerve block 2).
A 66-year-old male suffering from trigeminal neuralgia for 4 years that was refractory to pharmacologic therapy. Neurological examination was normal with no sensory deficit. Imaging showed no vascular compression or mass involving the trigeminal nerve. A diagnostic ultrasound-guided trigeminal nerve block via the pterygopalatine fossa with 4 mL of bupivacaine 0.25% and 4 mg dexamethasone provided immediate pain relief (100%) with sustained analgesia >50% at 2 weeks. Pain relief was not sustained at one month, with return to pretreatment symptoms. A series of injections were performed with similar intermittent analgesic effectiveness. The decision was made that the patient was a suitable candidate for pulsed radiofrequency application in the pterygopalatine fossa. We successfully used an alternative approach through the pterygopalatine fossa to treat trigeminal neuralgia using ultrasound guidance in an office setting. The case demonstrates the utility of ultrasound-guidance pulsed radiofrequency treatment in the pterygopalatine fossa as a potential alternative to other percutaneous techniques for patients with medical refractory trigeminal neuralgia 3).