RADIOFREQUENCY ABLATION FOR TRIGEMINAL NEURALGIA

A 53 years old female came to pain clinic with complaints of pain in left cheek for nearly 6years, starting from left ear radiating to her jaw, electric shock like unbearable pain, only for a minute or two , but frequency is 50-60times a day disturbing her daily activities like speaking, eating and yawning but not disturbing her sleep. It was triggered by innocuous stimuli like breeze of wind, touching of some points in cheek. For the above problem, she consulted many specialists and was given medications which gave her some relief but didn’t long lasted .

On examination, she was found to have classic trigeminal neuralgia (TGN) fitting into International classification of headaches (ICHD-3-TGN). According to this, classic TGN has

1. Recurrent Paroxysms of Electric shock like pain in the distribution of one or more divisions of Trigeminal nerve, with no radiation beyond and fulfilling the criteria b&c
2. Pain has all the following characteristics lasting from a fraction of seconds to two minutes, severe intensity, electric shock like shooting, stabbing or sharp in nature
3. Perpetuated by innocuous stimuli within the affected trigeminal distribution

Her Clinical features fit into the above criteria, though she was previously diagnosed to have dental pain, SUNCT, Hemicrania continua , Paroxysmal Hemicrania which are some of the D/Ds for TGN.

MRI is a imaging modality of choice and it shows aberrant vessel comprising the nerve roots in this case.

Treatment modalities includes Medical management where Carbamazepine is the drug of choice but in this case even after increasing the dose to maximal tolerable dose, patient was not having reasonable pain relief . Next options are interventions in the form of Glycerol Neurolysis (which becomes a history nowadays) , RF ablation of TGN and Balloon compression . Surgical management includes microvascular decompression (JANETTA Procedure ).

Patient was having pain only in V2 and V3 area and not willing or surgery, RF ablation was chosen for pain relief. Consent obtained after explaining the procedure in detail and complications that can occur, side effects like numbness and dysesthesia.

Procedure: With C-Arm image guidance (we prefer Cath Lab, For DSA purpose), Left Foramen Ovale is identified. Liberal Local infiltration was given in the entry point which 3cms away from the left angle of mouth. 10mm tip RF needle introduced with sequential lateral, anterior and oblique images to guide the needle to enter into the foramen ovale, where the 3main branches of trigeminal nerve are exiting. Usually they exit in the same order V1,V2V3 from medial to lateral. So the needle tip is kept at centre of foramen ovale and sensory and motor stimuli are tested . When needle touches V2 ,Patient complaints her usual pain in that territory . No motor stimuli confirms that needle is not on V3. Now 4 lesioning done at 60, 65,70◦C ,each for 120 seconds. Needle rotated laterally and again motor and sensory responses tested to confirm the needle tip on V3 . V3 being motor also, we get a response of Jaw movements . Again 4 lesioning done at the same temperature, each for 120 seconds . Needle removed and compression given at the puncture site.

Advantage of this procedure is, patient can be discharged on the same day after an observation for 2-3hours for any bleeding or undue side effects.

Usually, RF ablation gives a good pain relief for a minimum of one year. This patient also had a relief for nearly one year.

Conclusion: RF ablation of TGN is the most selective percutaneous procedure for classical TGN.