ClinicalTrials.gg
RecruitingNCT04144972Updated Jul 31, 2026

Closed-Loop Deep Brain Stimulation for Refractory Chronic Pain

An interventional study of Medtronic Summit RC+S or Percept RC in Spinal Cord Injuries, Nerve Injury and Pain, Postoperative, sponsored by University of California, San Francisco. Recruiting at 1 site in United States. Open to participants aged 22 Years to 80 Years. Per ClinicalTrials.gov, last updated 2026-07-31.

Sponsored by University of California, San Francisco · Not applicable, Interventional, and Treatment

From the registry’s dates

  • Started Oct 2019; still recruiting 7 years later.
Phase
Not applicable
Study type
Interventional
Enrollment
12
Allocation
Randomized
Ages
22 Years to 80 Years
Sex
All
01

Study summary

Chronic pain affects 1 in 4 US adults, and many cases are resistant to almost any treatment. Deep brain stimulation (DBS) holds promise as a new option for patients suffering from treatment-resistant chronic pain, but traditional approaches target only brain regions involved in one aspect of the pain experience and provide continuous 24/7 brain stimulation which may lose effect over time. By developing new technology that targets multiple, complimentary brain regions in an adaptive fashion, the investigators will test a new therapy for chronic pain that has potential for better, more enduring analgesia.

Read the detailed description

A diverse array of chronic pain syndromes are refractory to almost all treatment but involve pathological activity in similar brain regions. This suggests therapeutic potential for deep brain stimulation (DBS) for refractory pain disorders, but despite early promise, long-term efficacy is lacking. Current DBS devices are limited in anatomical reach, targeting only a subset of the distinct brain regions known to be important. Further, DBS therapy is bluntly applied in an "open-loop," continuous fashion without regard to underlying physiology. As a result of these shortcomings, DBS for pain is often ineffective or shows diminished effect over time. Loss of therapeutic effect may be due to nervous system adaptation or a failure of stimulation to accommodate patient- specific dynamics of pain processing. DBS could be significantly improved by seeking individually optimized brain targets or by using neural biomarkers of pain to selectively control stimulation when it is needed ("closed-loop" DBS). Better brain targets would also address the different dimensions of pain such as somatosensory (location, intensity and duration), affective (mood and motivation) and cognitive (attention and memory). The main goal of this study is to test the feasibility of personalized targeting of brain regions that support multiple pain dimensions and to develop new technology for "closed-loop" DBS for pain. The study team will develop data-driven stimulation control algorithms to treat chronic pain using a novel device (Medtronic Summit RC+S or Percept RC) that allows longitudinal intracranial signal recording in an ambulatory setting. By building this technology in an implanted device, chronic pain DBS is tailored to each patient and will advance precision methods for DBS more generally.

Beginning with an inpatient trial period, subjects with various refractory chronic pain syndromes will undergo bilateral surgical implant of temporary electrodes in the thalamus, anterior cingulate, prefrontal cortex, insula and amygdala. These regions have been implicated in the multiple dimensions of pain. The goal of the trial period is to identify candidate biomarkers of pain and optimal stimulation parameters for each individual, and to select subjects who show likelihood to benefit from the trial. A subgroup of 6 such patients will then proceed to chronic implantation of up to 3 "optimal" brain regions for long-term recording and stimulation. The invstigators will first validate biomarkers of low- and high-pain states to define neural signals for pain prediction in individuals (Aim 1). The investigators will then use these pain biomarkers to develop personalized closed-loop algorithms for DBS and test the feasibility of performing closed-loop DBS for chronic pain in weekly blocks (Aim 2). Finally, the investigators will assess efficacy of closed-loop DBS algorithms against sham (placebo) in a double-blinded crossover trial (Aim 3) and measure mechanisms of DBS tolerance. Our main outcome measures will be a combination of pain, mood and functional scores together with quantitative sensory testing. Successful completion of this study would result in the first algorithms to predict real-time fluctuations in chronic pain states and development of a new therapy for currently untreatable diseases.

02

Conditions studied

  • Spinal Cord Injuries
  • Nerve Injury
  • Pain, Postoperative
  • Post Herpetic Neuralgia
  • Complex Regional Pain Syndromes
  • Post-Stroke Pain
  • Post Radiation Brain Injury
  • Post Radiation Plexopathy
  • Nerve Root Avulsion

Keywords

  • Chronic Pain
03

In context

Spinal Cord Injuries

2,025 studies on the registry are indexed under Spinal Cord Injuries; 537 are open to participants now.

This study's planned enrollment of 12 is below the median of 24 across 1,633 interventional studies indexed under Spinal Cord Injuries.

Browse Spinal Cord Injuries studies →

Lead sponsor

University of California, San Francisco is the lead sponsor of 2,169 studies on the registry; 372 are open to participants now.

Of its 267 completed or terminated interventional studies of FDA-regulated products, 202 (76%) have results posted.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
22 Years to 80 Years
Sexes eligible
All
Accepts healthy volunteers
No

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  1. Age 22-80 years old
  2. Clinical diagnosis of a chronic pain syndrome including

    1. post-traumatic pain syndromes (e.g. root avulsions, nerve crush injuries, spinal cord injury)
    2. postsurgical pain syndromes (e.g., postmastectomy syndrome, post-thoracotomy syndrome, phantom limb pain, post-surgical spinal pain)
    3. postherpetic neuralgia
    4. complex regional pain syndrome
    5. atypical facial pain
    6. central pain syndromes (e.g. post-stroke pain, multiple sclerosis pain, post-radiation pain)
    7. post-radiation plexopathy
  3. Two or more years or more of medically refractory severe pain
  4. Average daily pain for the past 30 days reported as >6 on a 0-10 numeric rating scale (NRS)
  5. Pain that fluctuates over a range of at least 3 points on the NRS
  6. Patient has failed at least two pain medications from different classes as determined by a neurologist or pain management specialist with stable doses of medications for 30 days prior to baseline visit.
  7. Lack of a surgically correctible etiology for the pain as determined by 2 independent surgeons
  8. Ability to speak / read English
  9. Capable of understanding and providing
  10. Absence of significant cognitive impairment - score of 25 or greater on the (MoCA)
  11. Successful detection of pain biomarkers or positive symptomatic response to inpatient stimulation trial period if performed.

Exclusion criteria

Exclusion Criteria:

  1. Major medical co-morbidities increasing the risk of surgery including uncontrolled hypertension, coagulopathy, severe diabetes, major organ system failure, active infection or history of implant related infections, state or with \< 5 years
  2. Presence of cardiac pacemakers/defibrillators, implanted medication pumps, intra-cardiac lines, any intracranial implants (e.g., aneurysm clip, shunt, cochlear implant, electrodes) or other implanted stimulators not compatible with RC+S system
  3. Pregnancy or breast feeding: all women of child bearing potential will have a negative urine pregnancy test prior to undergoing their surgical procedure.
  4. Active depression (BDI > 20), Suicide attempt \</= 12 months or imminent suicide risk, or other untreated or uncontrolled psychiatric illness that evaluating psychiatrist would recommend exclusion of patient after neuropsychiatric evaluation.
  5. History of substance abuse in past 3 years
  6. Inability to stop anticoagulation or anti-aggregation therapy for surgery and recovery.
  7. Implantable hardware not compatible with MRI or with the study.
  8. MR abnormalities that suggest an alternative diagnosis or contraindicate surgery
  9. Previous cranial ablative surgery.
  10. Previous deep brain stimulation surgery using an RC+S incompatible system
  11. Major neurological disorder other than the one that led to the chronic pain including epilepsy or a neurodegenerative condition including inability to recharge the device.
  12. Requires diathermy, electroconvulsive therapy (ECT) or transcranial magnetic stimulation (TMS)
  13. Allergies or known to materials in the Summit RC+S system
  14. Patients may be excluded from enrollment due to a condition that, in the judgment of the PI, significantly increases risk or reduces significantly the likelihood of benefit from DBS.
Terms in these criteria, in plain language(8)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

Relapsed and refractory

Relapsed: the illness came back after treatment had worked. Refractory: it did not respond to treatment, or stopped responding while still on it.

Informed consent

Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.

You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.

MMSE and MoCA

Short tests of memory and thinking, each scored out of 30. Lower scores suggest more difficulty; criteria give a range, either to include people with memory problems or to leave them out.

Immunosuppression

A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.

Read whether the line is about a condition or about medicines, and which medicines and doses it means.

Cancer (malignancy)

Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.

Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.

Life expectancy

The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.

Platelets

Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.

Hypersensitivity

An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.

05

Study design

Phase
Not applicable
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Crossover assignment
Masking
Single (Participant)
Enrollment
12 participants (estimated)

Study arms

  • Active comparator
    Active DBS

    Chronic brain recordings and stimulation with bilateral implantations in pain-related brain regions. All participants will participate in active DBS, blinded to the participant.

    Device: Medtronic Summit RC+S or Percept RC

  • Sham comparator
    Inactive DBS

    Non-active chronic brain stimulation in pain-related brain regions. brain recordings will remain active during this period. All participants will participate in inactive DBS, blinded to the participant.

    Device: Medtronic Summit RC+S or Percept RC

Interventions

  • DeviceMedtronic Summit RC+S or Percept RC

    The investigators will perform DBS versus sham (randomized) to evaluate efficacy of stimulation for analgesia. Closed-loop DBS will be compared to open-loop DBS in a patient blinded, randomized fashion after initial, efficacy evaluation.

06

What researchers measure

Primary outcomes

  1. Feasibility of identifying personalized physiological biomarkers and an optimal stimulation site during the temporary (externalized) trial stage

    Identifying biomarkers in machine learning models that exceed chance and stimulation sites that provide clinically meaningful reductions in chronic pain during a temporary brain stimulation and recording period in hospital

    Time frame: 60 days

  2. Feasibility of implementing individualized closed-loop DBS for chronic pain

    Time frame: 2 years

Secondary outcomes

  1. Safety and Rate of Adverse Events

    Quantifying the rate and category of all adverse events

    Time frame: 2 years

Other outcomes

  1. Pain Numerical Rating Scale Improvement - Exploratory

    Quantifying percent improvement and absolute improvement on Numerical Rating Scale (NRS) 0-10 scale of pain severity,

    Time frame: 2 years

  2. Pain Visual Analog Scale improvement - Exploratory

    Quantifying percent improvement and absolute improvement on Visual Analog Scale (VAS) 0-100 scale of pain severity

    Time frame: 2 years

  3. McGill Pain Questionnaire Improvement - Exploratory

    Quantifying percent improvement and absolute improvement on McGill Pain Questionnaire (short form - version 2)

    Time frame: 2 years

  4. Health related quality of life

    Quantifying change in multiple quality-of-life measures with the short form 36, including physical, emotional, and pain-related sub-scores from baseline to long-term follow-up.

    Time frame: 2 years

  5. Becks Anxiety Inventory

    The Becks Anxiety Inventory is commonly used assessment tools to quantify and track anxious mood state over time.Its a single value outcome measurement ranging from 0 to 63, with 63 the most anxious.

    Time frame: 2 years

  6. Becks Depression Inventory

    The Becks Depression Inventory is commonly used assessment tools to quantify and track depression mood state over time. Its a single value outcome measurement ranging from 0 to 63, with 63 being the most depressed.

    Time frame: 2 years

  7. Activity Tracker (Fitbit) - Activity (Steps)

    Each patient will be given a fitbit activity monitor which can record steps taken, flights of stairs climbed, heart rate and sleep quality. These measures will be used to infer functional improvement over time. Steps will be recorded as steps per hour or day and evaluated against changes in pain level reported in the VAS or NRS.

    Time frame: 2 years

07

Study locations

1 of 1 sites recruiting
08

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Jul 31, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
09

Registry details

Key details

Study ID
NCT04144972
Responsible party
Prasad Shirvalkar, MD, PhD (Associate Professor of Anesthesia, University of California, San Francisco) — Principal investigator
First posted
Oct 30, 2019
Start date
Oct 24, 2019
Primary completion
Oct 24, 2029 (estimated)
Completion
Oct 24, 2030 (estimated)
Last update
Jul 31, 2026

Study contacts

Catherine Borror
Contact
chronicpain@ucsf.edu
‪(415) 353-3494
Prasad Shirvalkar, M.D., Ph.D
Contact
Prasad.Shirvalkar@ucsf.edu
‪(415) 691-7587‬
Prasad Shirvalkar, M.D., Ph.D
principal investigator · University of California, San Francisco
Edward Chang, M.D.
principal investigator · University of California, San Francisco
Philip Starr, M.D., Ph.D.
principal investigator · University of California, San Francisco

Oversight

Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
Yes
View the source record on ClinicalTrials.gov ↗

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