A Clinical Case Report on Transcranial Low-Intensity Focused Ultrasound Neuromodulation for Central Post-stroke Pain

Xiangjun Feng^1*Sijin He²Kaixuan Luo³Xiang Li⁴Jiajia Duan⁴Lei Ding⁵Moxian Chen³Xuan Xu³Xianghua Sun⁶Lijuan Ao³

• ¹Department of Rehabilitation, First Affiliated Hospital of Kunming Medical University, Kunming, China
• ²Department of Rehabilitation, Kunming Municipal Hospital of Traditional Chinese Medicine, Kunming, China
• ³School of Rehabilitation, Kunming Medical University, Kunming, China
• ⁴Department of Radiology, The Third People's Hospital of Kunming, Kunming, China
• ⁵The Third People's Hospital of Kunming, Kunming, China
• ⁶Department of Cadre Rehabilitation and Surgery, First Affiliated Hospital of Kunming Medical University, Kunming, China

Central post-stroke pain (CPSP) manifests as persistent or intermittent pain following cerebral infarction or hemorrhage, described as "one of the most agonizing, disabling, and refractory pain syndromes" and its treatment represents a significant clinical challenge. In this case, we attempted to use transcranial low-intensity focused ultrasound (tLIFU), an emerging noninvasive neuromodulation approach which is distinct from pharmacological as well as traditional neuromodulation methods to treat CPSP patient and achieved satisfactory outcomes. This may inspire new perspectives on innovative pain management. A 66-year-old male veteran suffered long-term CPSP with unsatisfactory pain relief from prior paregoric interventions including Transcranial Magnetic Stimulation (TMS). Blood Oxygenation Level Dependent functional Magnetic Resonance Imaging (BOLD-fMRI) revealed abnormal activity which can be modulated by analgesic medication adjustment in the region of interest (ROI), which was anatomically consistent with the cingulum bundle. Given this, we employed tLIFU to demonstrate deep stimulation of the ROI. Remarkable pain reduction was observed after one week of tLIFU neuromodulation and gabapentin dose was slightly tapered. The analgesic effects generated by tLIFU treatment sustained through 5-month follow-up without adverse events reported. Since the 120-day mark, the patient has remained off analgesic and the region of the ROIs exhibited normalized activity pattern as revealed by BOLD-fMRI at the 150-day follow-up. Additionally, significant clinical improvement was noted in the patient's emotional state. This case report highlights the potential of tLIFU technology to expand therapeutic options in clinical pain management. Exploratory researches on the clinical efficacy and mechanisms of tLIFU in pain treatment will contribute to a deeper understanding of pain pathogenesis and the development of novel therapeutic strategies.