Guided by Real-Time Ultrasound with Integrated CT Imaging: Neurofrequency Thermal Ablation for Treating Refractory Trigeminal Neuralgia
Update Date：2024/09/05，
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Trigeminal neuralgia is one of the most common causes of facial pain, with patients experiencing sensations such as sharp, explosive, burning, or tingling pain in the face, which can occur multiple times a day or even hundreds of times daily, causing significant distress.
For treating trigeminal neuralgia, initial management often involves stabilizing the trigeminal nerve with anticonvulsant medications. If medication proves ineffective, minimally invasive or surgical treatments may be considered. Compared to surgical options, minimally invasive treatments (such as localized nerve injections and neurofrequency thermal ablation) offer advantages like smaller incisions and quicker recovery times. However, these techniques heavily rely on imaging guidance to accurately position the needle tip at the nerve for treatment, requiring the operator to undergo rigorous training to avoid complications.
Traditionally, two imaging guidance techniques have been used for minimally invasive treatment of trigeminal neuralgia: fluoroscopic guidance and CT guidance. While both methods have become quite advanced, they still have limitations. Neither fluoroscopy nor CT allows for real-time visualization of vascular structures, which can lead to complications such as bleeding from punctured vessels, causing facial swelling that often worries patients.
With the advancement of ultrasound technology, integrating CT imaging with real-time ultrasound has become a trend in modern practices. Here’s a simple description of how this is achieved: First, a magnetic tracking device is attached to the patient’s head. Next, a CT scan of the cranial base is performed. The CT images are then transferred to the ultrasound machine. The ultrasound probe is placed on the patient’s face, and by pressing a synchronization button, the CT images appear on the ultrasound screen (Figure 1). As the ultrasound probe is moved, the CT images and ultrasound images adjust synchronously, providing real-time guidance.
Ultrasound is often criticized for its complexity, particularly with cranial base imaging. The challenge arises from the obscuration of the facial bones, making it difficult to accurately locate the nerve openings at the cranial base. With the integration of real-time CT imaging into ultrasound, however, this challenge is mitigated.
By marking the desired nerve openings on the CT images displayed on the ultrasound screen, corresponding markers appear on the real-time ultrasound images (Figure 1). This allows the needle tip to be precisely inserted into the marked points, achieving the crucial goal of "accurate imaging guidance" during the procedure.
We have successfully applied the "Real-Time Ultrasound with Integrated CT Imaging" guidance technique in several patients with refractory trigeminal neuralgia, performing neurofrequency thermal ablation and effectively reducing their trigeminal pain. This technique allows for clear visualization of the blood vessels along the puncture path, which helps avoid hematomas caused by punctured vessels and accurately guides the needle tip to the cranial base nerve openings of the trigeminal nerve, thereby enhancing the efficacy of the high-frequency thermal ablation (Figure 2). We believe that the precise use of this technology can significantly reduce patient anxiety and physician concerns, ultimately providing more effective treatment for a greater number of patients.
Dr. Hsu Yi-Chih from the Department of Radiology