Resolution of trigeminal neuralgia following minimal coil embolization of a primitive trigeminal artery associated with a cerebellar arteriovenous malformation

Abstract

Dear Editor, Trigeminal neuralgia (TN) is most often caused by the superior cerebellar artery (SCA), and microvascular decompression (MVD) is the first treatment option for uncontrollable TN by medication [2]. We report a case of TN caused by a primitive trigeminal artery (PTA) as a cerebellar arteriovenous malformation (AVM) feeder. Because the middle portion of the PTA involved perforating arteries, we occluded only the distal portion of the PTA with coils, and succeeded in relieving the pain. This minimal embolization of an offending artery with coils may be a treatment option for selected cases of TN. A 53-year-old man suffered from left-sided TN. Imagings showed a 6.3-cm AVM in the left hemispheric cerebellum associated with the left PTA (Fig. 1a, b). The Spetzler– Martin grade was V. We first treated the patient with antiTN medication. The pain became worse, and the patient had difficulty in eating. A diagnostic angiogram was performed. The PTAwas a feeder of the AVM (Fig. 1d). Detailed threedimensional analysis showed that the middle portion of the PTA (attached to the trigeminal nerve) was likely to be responsible for TN (Fig. 1c). We planned to perform endovascular treatment because MVD was technically difficult owing to the large AVM. We occluded only the distal portion of the PTA with coils expecting a collapse of the middle portion of the PTA and relief of the pain (Fig. 1e). Although we could not achieve occlusion or flow stagnation of the middle potion of the PTA, we finished the procedure because small branches at the middle portion appeared after occlusion of the distal portion of the PTA and they might have supplied normal brain parenchyma. There were no periprocedural complications. The pain was completely resolved in 1 month. Angiographic follow-up 10 months after the operation showed that the middle portion of the PTAwas narrowed and string-like, and that the distal portion of the PTAwas occluded (Fig. 1F). This narrowing suggested that contact of the PTA and the trigeminal nerve had been released. The patient remained pain-free for 12 months after the operation. Our patient had two rare conditions, which involved TN associated with both a PTA and a cerebellar AVM. To the best of our knowledge, this is the first report of these rare conditions. There are 21 cases previously reported to have TN associated with a PTA [3, 4, 7–9]. In 18 out of the 21 cases, MVD was performed, and the pain was relieved. In the remaining three cases, medication was sufficient. Considering these results, MVD would be the first option for TN associated with a PTAwhen medical treatment fails. However, in our patient, MVD was technically difficult because of the large cerebellar AVM. Lesley reviewed the literature and summarized 59 cases of TN associated with AVM [5]. Most of them were surgically treated. Only four cases of TN have been treated with endovascular surgery, and they were all associated with AVM, but not with a PTA [1, 5, 6, 10]. One of these patients [1] was treated with coils, and the other three [5, 6, 10] were treated with ethylene-vinyl alcohol copolymer (Onyx; eV3, Neurovascular, Irvine, CA, USA). In all of these four patients, the pain was relieved. Our treatment strategy was K. Kono (*) : T. Terada Department of Neurosurgery, Wakayama Rosai Hospital, 93-1 Kinomoto, Wakayama 640-8505, Japan e-mail: vyr01450@gmail.com