Low-Energy Transcranial Navigation-Guided Focused Ultrasound for Neuropathic Pain: An Exploratory Study
Dong Hoon Shin, Seong Son, Eun Young Kim
Brain Sciences 2023, 13, 1433 · 10.3390/brainsci13101433
Abstract
Neuromodulation using high-energy focused ultrasound (FUS) has recently been developed for various neurological disorders, including tremors, epilepsy, and neuropathic pain. We investigated the safety and efficacy of low-energy FUS for patients with chronic neuropathic pain. We conducted a prospective single-arm trial with 3-month follow-up using new transcranial, navigation-guided, focused ultrasound (tcNgFUS) technology to stimulate the anterior cingulate cortex. Eleven patients underwent FUS with a frequency of 250 kHz and spatial-peak temporal-average intensity of 0.72 W/cm 2 . A clinical survey based on the visual analog scale of pain and a brief pain inventory (BPI) was performed during the study period. The average age was 60.55 ± 13.18 years-old with a male-to-female ratio of 6:5. The median current pain decreased from 10.0 to 7.0 ( p = 0.021), median average pain decreased from 8.5 to 6.0 ( p = 0.027), and median maximum pain decreased from 10.0 to 8.0 ( p = 0.008) at 4 weeks after treatment. Additionally, the sum of daily life interference based on BPI was improved from 59.00 ± 11.66 to 51.91 ± 9.18 ( p = 0.021). There were no side effects such as burns, headaches, or seizures, and no significant changes in follow-up brain magnetic resonance imaging. Low-energy tcNgFUS could be a safe and noninvasive neuromodulation technique for the treatment of chronic neuropathic pain.
Abstract via europepmc.
Exposures
Exposure 1: tcNgFUS to bilateral anterior cingulate cortex (Brodmann area 24, dorsal ACC)
Target: dorsal anterior cingulate cortex — “bilateral anterior cingulate cortex (Brodmann area 24, dorsal ACC)”
Device: Neurosona · Neurosona Corporation · NS-US100 ✓
| Waveform | pulsed | |
|---|---|---|
| Fundamental frequency (kHz) | 250 | ✓✓✓ |
| Pulse duration (ms) | 5, 10swept | ✓✓✓ |
| Pulse repetition frequency (Hz) | not reported | ⚑ |
| Duty cycle (%) | 50, 70swept | ✓✓✓ |
| Sonication duration (s) | not reported |
| Free-field pressure (kPa) | not reported | |
|---|---|---|
| Free-field Isppa (W/cm²) | not reported | |
| Free-field Ispta (W/cm²) | not reported | |
| In-situ estimate | not reported | |
| In-situ pressure (kPa) | not reported | |
| In-situ Isppa (W/cm²) | not reported | |
| In-situ Ispta (W/cm²) | not reported | |
| Ispta, domain unspecified (W/cm²) | 0.72 | ✓✓✓⚑ |
Low-energy FUS had a frequency of 250 kHz, spatial-peak temporal-average intensity of less than 0.72 W/cm2, and tone burst duration of 5–10 ms. Stimulation was performed with a 50–70% duty cycle (the rate occupied by an ultrasonic donation per second). The total stimulation time, including the rest period, did not exceed 30 min in all patients. Additionally, the device was used within a range that does not exceed a Mechanical Index of 1.9 (in situ peak rarefaction pressure less than 0.95 MPa according to the Food and Drug Administration safety standards for ultrasonic imaging devices). Treatment was carried out three times a week for 2 weeks.
Flags from extraction
n_subjects— 12 patients enrolled/recruited; 1 withdrew consent during follow-up leaving 11 in the final analysis. n_subjects reported here is the enrolled/treated total (12); flagged because analysed n=11.n_sessions_per_subject— Paper states frequency (3x/week for 2 weeks) rather than a single total session count; 6 is derived by simple multiplication of the stated schedule.exposures[0].timing.pulse_repetition_frequency_hz— PRF is not numerically stated; only tone-burst duration and duty cycle are given, and duty-cycle/PRF cannot be used to resolve pulse duration since pulse duration is already directly stated as a range.exposures[0].unspecified_domain.pressure_kpa— Paper states the device was operated 'within a range that does not exceed... in situ peak rarefaction pressure less than 0.95 MPa' – this is a stated safety ceiling/compliance limit, not necessarily the actual delivered pressure, so no specific pressure value was recorded.exposures[0].unspecified_domain.ispta_w_cm2— Intensity of 0.72 W/cm2 (abstract) / 'less than 0.72 W/cm2' (Methods) is not explicitly assigned to a free-field or in-situ domain.