Background: Trigeminal neuralgia (TN) is the most common excruciating cranial neuralgia in the elderly population. Radiofrequency thermocoagulation (RFT) of the trigeminal ganglion is an alternative treatment for medically intractable patients with TN. RFT cannula tip position is an important issue since it is related to treatment outcome and patient safety.
Objectives: The purpose of this study was to evaluate the fluoroscopic position of a cannula tip when a maximal stimulation-induced paresthesia was obtained and the treatment outcome using a Barrow Neurological Institute (BNI) pain scale.
Study design: Retrospective analysis.
Setting: An interventional pain management practice in South Korea.
Methods: The final cannula tip position obtained under maximal electrical stimulation of the face was analyzed using previously saved fluoroscopic images.
Results: The cannula tip was located exactly in the clival line in 10 patients (29.4%) with maxillary division (V2) TN. There were 24 patients of V2 TN (70.5% ) in whom the cannula tip was located below the clival line. Over 50% of cannula tips were located at -11 mm to -15 mm below the clival line in mandibular division (V3) TN. Forty-four patients (83%) who received RFT in the trigeminal ganglion demonstrated BNI I or II.
Limitations: The number of patients with V3 TN was smaller than that of V2 TN. Only short-term efficacy was evaluated, but not long-term efficacy or recurrence rate of facial pain.
Conclusions: Nearly 70% of patients in V2 TN and all patients in V3 TN, the cannula tip was positioned below the clival line. RFT of the trigeminal ganglion showed a successful treatment outcome with BNI I or II in 83% of patients.
Keywords: clival line; fluoroscopic position; pain scale; radiofrequency; stimulation-induced paresthesia; Cannula tip.