Two cases of glossopharyngeal neuralgia successfully treated with pulsed radiofrequency treatment.

Dear Editor, Glossopharyngeal neuralgia (GPN) is an uncommon cause of facial pain with a crude incidence rate estimated to be 0.7 per 100,000 yearly.1 GPN incidence is only 0.2% to 1.3% that of the more known facial pain entity trigeminal neuralgia.2 The character and distribution of pain is often diagnostic; shooting from the pharynx, tonsil, and posterior base of tongue upwards to the Eustachian tube and inner ear or to the mandibular angle.3 GPN can be categorised as either primary or secondary GPN.3 Surgical treatment has traditionally been described to be more successful than nonsurgical treatment, but is unfortunately reported with higher rates of mortality and morbidity.3,4 Pulsed radiofrequency application (PRF) is a nondestructive neuromodulatory method that can be used to treat neuropathic pain.5 Short pulses of radiofrequency energy, delivered at a constant temperature, produce central and peripheral neuromodulatory effects.6,7 Pulsed radiofrequency application (PRF) for secondary glossopharyngeal neuralgia had only been previously described by Shah et al8 in 2003. We present our experience with 2 patients with secondary glossopharyngeal neuralgia satisfactorily treated by PRF treatment of the glossopharyngeal nerve. All patients presenting to our hospital with refractory facial neuralgias receive a multidisciplinary assessment, with complete neurological evaluation and magnetic resonance imaging. Written consent for glossopharyngeal nerve PRF was obtained after the diagnosis of GPN was made. PRF treatment of the glossopharyngeal nerve was performed under fl uoroscopic guidance. After skin preparation and local anesthetic infi ltration, a 22G 45 mm insulated radiofrequency needle with 5 mm active tip was advanced in a medial direction (C-arm in lateral orientation) until bony contact with the styloid process was made. The needle was then walked off the posterior portion of the styloid process and advanced another 0.5 cm medially (Fig. 1). An antero-posterior check view shows the tip of the needle just medial to the styloid process. Figure 2 gives a pictorial representation of how the technique was performed. Sensory stimulation at 50 Hz up to 0.5 V was used to reproduce concordant pain at the base of the tongue, pharynx, and tonsils. Motor stimulation up to 1.0 V at 2 Hz was negative. Contractions of the muscles innervated by the phrenic and spinal accessory nerves were absent. Both patients remained haemodynamically stable without any bradycardic or hypotensive episodes. Pulsed radiofrequency application was then initiated at 45 V, 4 Hz and 10 milliseconds for 6 min after positive sensory stimulation. We do not routinely give local anaesthetic or steroid solutions at the fi nal needle tip position because of