The short version
- After spinal cord surgery, doctors can’t see how blood is flowing around the injury once the wound is closed, and a Johns Hopkins team built a small ultrasound implant to let them.
- In pigs and human cadavers the device imaged the cord on demand and tracked bleeding and blood flow, and in healthy pigs focused ultrasound from the same device changed blood-flow speed.
- It is still a preclinical device with no published numbers on safety or benefit, though the FDA gave it Breakthrough Device designation in 2023.
A Johns Hopkins team has built an ultrasound device that sits on the spinal cord after surgery and reports back on the injury. It is described in Science Advances, published November 4. So far it has been tested only in pigs, human cadavers and lab models.
The problem it is meant to solve
After an acute spinal cord injury, surgeons often operate to take pressure off the cord. The days after that surgery are a critical window. Swelling, bleeding or a drop in blood flow around the injury can make the damage worse.
Once the wound is closed, though, no one can see the injured spot. The paper’s authors point out that care in those days rests mostly on whole-body measures. The team’s hope is that an implant could cut down on scans that mean moving a patient who may not be able to move. About 18,000 people in the US have a spinal cord injury each year, according to the university, most often in vehicle crashes.
The device
It is called MUSIC, for Multimodal Ultrasound System for Injury Care. It is about the size of a small bandage. The surgeon places it in the epidural space, over the cord at the injury site, during the standard decompression operation, and it is meant to come out later. The team calls it a “mobile MRI.”
It does three jobs. It takes ordinary ultrasound images of the cord’s anatomy. It uses Doppler ultrasound to measure blood flow in the small vessels near the injury. And it can deliver focused ultrasound, the beam-steering technique we have covered for Parkinson’s and schizophrenia, here aimed at changing how blood moves rather than at destroying tissue.
“When the biology of spinal cord injury is local, our devices should also be able to track and treat local physiology,” said Amir Manbachi, the principal investigator.
What the study did
The 43-author team, led by Manbachi and the neurosurgeon Nicholas Theodore, worked up from computer simulations and benchtop tests to human cadavers and then pigs. According to the abstract, the implant let them image the cord on demand, follow a collection of blood (a haematoma) over time, and track the flow pattern around a region fed by a sulcal artery, one of the small vessels supplying the cord’s centre.
The treatment arm is the earliest part. In healthy pigs, focused ultrasound from the device changed the speed of blood flow in the cord. The abstract calls this proof of concept. It does not say the treatment was tried in injured animals.
What is not yet known
A lot. The abstract gives no numbers: no count of pigs or cadavers, no ultrasound settings, no size of the blood-flow change and no safety findings. We could read the abstract and the university’s release, but not the full paper, which sits behind a subscription. The release describes the implant as feasible and safe in animals, with no figures.
Nothing in this study shows that patients would recover better. The authors call it an early midpoint in a longer programme, and the release says the treatment uses need more work. Two of the authors work for Sonic Concepts, a company that makes ultrasound transducers. The funding is not listed in the record we read.
The FDA gave the device Breakthrough Device designation in 2023. That designation is not evidence that it works.
Why it matters
Most of what we write about focused ultrasound happens from outside the skull. MUSIC goes the other way. It puts the transducer right on the tissue, where it can listen and act every day of the recovery window.
“Timing is critical for recovery,” Theodore said. If a device can flag falling blood flow in time to treat it, that would change intensive care after spinal injury. Whether it can is still an open question.
What to watch: the team’s next preclinical studies, especially any that test the blood-flow treatment in injured animals, and a first-in-human study, for which no date has been given.
