Phantom Neuro implanted its subdermal prosthetic control device in the first human participants. The outpatient procedure took about an hour and required no general anesthesia.

Most upper-limb prosthetic systems today read muscle signals from the surface of the skin. That works well enough under controlled conditions. It works less well when a socket shifts, when the skin sweats, or when electrodes drift off the muscle belly they’re supposed to cover. Phantom Neuro is trying to fix the signal problem by going under the skin instead.

The company announced this week that the first participants in its CYBORG early feasibility study have received implants of its Phantom X device. The implants were placed at Cabrini Health in Melbourne, Australia, by Michael Lo, MD, a plastic and reconstructive surgeon. Each procedure was outpatient, took roughly an hour, and did not require general anesthesia. Prosthetic care, occupational therapy, and follow-up testing are being provided by ProMotion Prosthetics and Enable Rehab.

Phantom X is a sensor placed beneath the skin, over the muscles of the residual limb. When a person with upper-limb loss attempts to move their missing fingers or wrist, those muscles still contract and generate electrical signals. The device picks those signals up and transmits them wirelessly to a compatible prosthetic device, which then moves in the direction the person intended.

The functional principle is not new. Myoelectric prosthetics have worked on this principle since the 1960s, reading the same residual muscle signals with electrodes on the skin surface. The distinction Phantom Neuro is drawing is about signal quality and reliability. Surface electrodes are sensitive to how well the socket fits, how the skin sweats, and how the electrode holds position during activity. A subdermal sensor is physically closer to the signal source, enclosed, and not dependent on skin contact.

“Most people who have lost their limbs still have the ability to control their limbs, down to the individual fingers, in their mind’s eye,” said Connor Glass, MD, founder and CEO of Phantom Neuro. “Our goal is to capture signals associated with intended movements of that phantom limb and translate them into actual movements of a robotic limb.”

What the study is actually testing

CYBORG is an early feasibility study, the clinical stage that comes before pivotal trials and well before any regulatory approval or commercial use. The primary goal is to evaluate safety, performance, and usability in a small number of participants. Phantom Neuro has not reported efficacy data; the implantations are a procedural milestone, not a finding about how well the control works in practice. That data comes later.

Phantom X is investigational and not approved for commercial use. The announcement does not specify how many participants the study plans to enroll or what the follow-up timeline looks like.

“This study is an opportunity to evaluate everything from the surgical procedure to the technology itself and how these innovations can impact participants’ lives over time,” Lo said.

What this means for people using upper-limb prosthetics

A recurring reason for upper-limb prosthetic abandonment is unreliable control. A sensor that does not drop out when the socket moves or the arm sweats would address something real. Whether the subdermal approach actually delivers that is what CYBORG is designed to find out.

The surgical scale described here is less intensive than osseointegration, which anchors to bone, and considerably less intensive than intracortical brain-computer interfaces, which require surgery inside the skull. Outpatient, no general anesthesia, roughly an hour: that puts it closer to minor orthopedic procedures than to neurosurgery. Any implant still carries risks related to infection, device migration, and long-term biocompatibility, and those risks are part of what the feasibility study is assessing.

For people using prosthetics now: Phantom X is not available. The timeline to availability depends on the outcome of the feasibility study, followed by larger clinical trials. If the device performs as intended, the path from these first implants to clinical access is years, not months.

Phantom X is investigational and not approved for commercial use. This article describes an early research study and does not constitute medical advice. Talk with a certified prosthetist about prosthetic control options for your situation.