Trigeminal radiofrequency ablation

Trigeminal radiofrequency ablation, also known as trigeminal radiofrequency rhizotomy, is a percutaneous interventional procedure used to treat trigeminal neuralgia. It is the most popular technique for trigeminal ablation.

Indications

• trigeminal neuralgia resistant to traditional medical treatment but with an excellent response to trigeminal nerve ganglion block

Contraindications

• local infection
• increased intracranial pressure

Procedure

Trigeminal radiofrequency ablation utilizes the thermal energy produced by the radiofrequency waves to create an area of nerve tissue destruction to alleviate the pain sensations transmitted by this nerve ¹.

Technique

The procedure is done with the patient in a supine position with the head extended under the guidance of fluoroscopy and follows a series of steps ²:

1. C-arm is manipulated until an oblique submental view visualizing the foramen ovale is obtained
2. patient is consciously sedated to increase comfort and reduce anxiety
3. local anesthesia is administered at approximately 2 cm lateral to the commisura labialis of the affected side
4. a 22 gauge, 10 cm radiofrequency cannula with a 5 mm active tip is inserted and advanced in a coaxial manner towards the foramen ovale
5. after reaching the foramen ovale, the cannula is advanced approximately 2-4 mm further until the tip of the electrode is at the junction of the petrous ridge and the clivus
6. the stylet is removed, and aspiration is performed to confirm that the dura has not been penetrated (contrast injection can help confirm this)
7. trigeminal nerve test stimulations are then done to further confirm location (stimulation of the nerve roots with 2 Hz should cause contraction of the lower jaw)
8. ablation of the trigeminal nerve ganglion is done at 60 degrees Celsius for 60 seconds

Complications

Common

• post-procedural discomfort ¹
• bleeding ¹
• neuropathic pain ¹

Rare

• diminished corneal reflex ²
• masseter weakness and paralysis ²
• dysesthesia ²

Extremely rare

• anesthesia dolorosa ²
• keratitis ²
• transient paralysis of CN 3 and CN 6 ²
• CSF leakage ²
• permanent CN 6 palsy ²

Outcomes

Compared to other ablative techniques (gamma knife surgery, balloon compression, or glycerol rhizolysis), radiofrequency ablation has the highest rate of complete pain relief ¹. Initial relief is achieved in 98% of patients with recurrence of pain at 12 months from 15-20% of patients ².