Comment on: “Pulsed radiofrequency treatment for the management of trigeminal neuropathic pain”

Dear Editor,

We read with interest the case report by Hassan et al.[1] on pulsed radiofrequency (PRF) treatment for the management of post-traumatic neuropathic pain (PTNP) following tooth extraction involving the trigeminal nerve. We congratulate the authors and would like to present our views.

First, Hassan et al.[1] reported a case of PTNP with continuous severe pain, hyperalgesia, and allodynia treated with PRF of trigeminal ganglion (TG). They also state that PRF of TG is more advantageous than CRF due to fewer complications. Nevertheless, the conventional radiofrequency ablation (CRF) of TG is the established modality for neuropathic pain of trigeminal origin. CRF is more effective in immediate and long-term pain relief than PRF with pain relief of almost 85–90% compared to 75% of immediate pain relief of PRF.[2,3] Moreover, serious complications of CRF are very rare, and the most common complications like facial numbness and masseter weakness are mild, temporary, and resolve spontaneously.[4] With proper preprocedure counseling, patients accept these complications as a meager price for achieving satisfactory pain relief.

Second, the involved nerve was the mandibular division (V3 division) of the trigeminal nerve in that case report.[1] In such cases, CRF of the peripheral nerve (V3 division) is equally effective as CRF of TG with less complication rate and pain relief is superior to PRF.[5] Hassan et al.[1] did not mention the signs and symptoms suggestive of the sympathetic nervous system involvement, which is possible due to traumatic neuropathy and symptoms of long duration. In such cases, radiofrequency ablation (RFA) of TG can be combined with RFA of sphenopalatine ganglion after a successful diagnostic block.

Third, Hassan et al.[1] did PRF of TG at 42 degrees Celsius for 180 seconds, but the voltage used was not mentioned. We presume that it was a standard voltage PRF which resulted in 50% pain relief. The use of high-voltage PRF gives better analgesia than standard-voltage PRF without increasing side effects.[6]

Last, we would like to point out the misinterpretation of the results of a study by Erdine et al.[3] quoted as reference number 19 by Hassan et al.[1] Hassan et al.[1] mention that the study by Erdine et al.[3] concluded that usage of PRF for the management of trigeminal neuropathic pain resulted in a good response compared to the conventional radiofrequency (CRF) techniques with fewer side effects and complications.[1] However, Erdine et al.[3] concluded that PRF was not an effective method for idiopathic trigeminal pain control and all the patients recruited in the PRF group received CRF after 3 months due to persistent intractable pain even after PRF.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.