Phantom Neuro implanted its prosthetic control device in the first human participants. What the study is, and what it is not.

Phantom Neuro announced this week that the first participants in its CYBORG early feasibility study have received implants of Phantom X, a small sensor device placed beneath the skin in the residual limb. The device picks up electrical signals from residual muscles when a person attempts to move their missing hand or fingers, then sends wireless commands to a compatible prosthetic limb.

The procedures took place at Cabrini Health in Melbourne, Australia, performed by Michael Lo, MD, a plastic and reconstructive surgeon. Each procedure was outpatient, lasting roughly an hour, without general anesthesia. Prosthetic care, occupational therapy, and study testing are provided by ProMotion Prosthetics and Enable Rehab.

Phantom X is investigational. It is not approved for commercial use. The study is ongoing, and any conclusions about safety or effectiveness depend on further evaluation.

How the device works

Most upper-limb myoelectric prostheses in clinical use today rely on surface electrodes: sensors built into or pressed against the inside of the prosthetic socket that read electrical signals through the skin. The approach works, but signal quality can be affected by sweat, socket fit, skin condition, and residual limb volume changes across the day. A person has to wear the socket to use it.

Phantom X takes a different approach. The sensor sits under the skin, over the muscles in the residual limb, rather than on the surface. According to Phantom Neuro, when a person attempts to move their missing fingers or wrist, those remaining muscles still produce electrical signals. The implanted sensor detects those signals and relays them wirelessly to a compatible prosthetic device, without the prosthetic socket in the loop at the point of signal capture.

Connor Glass, MD, founder and CEO of Phantom Neuro, framed the concept this way: “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. This is what is colloquially known as a phantom limb. Our goal is to capture signals associated with intended movements of that phantom limb and translate them into actual movements of a robotic limb.”

Lo described the appeal in terms of reach: “What excites me most about this technology is the scale of impact that is possible due to the relative simplicity of the surgical procedure. Great technology that is safe and easy to implement can impact a lot of people’s lives.”

How this compares to other approaches

Researchers have pursued subcutaneous and implanted approaches to prosthetic control for years. Osseointegration attaches the prosthetic directly to the bone and can route electrodes through the implant. Targeted muscle reinnervation (TMR) reroutes residual nerves to create new, distinct muscle signal sources. The agonist-antagonist myoneural interface (AMI) preserves the paired muscle relationships that normally signal joint position and force.

Each of those requires more extensive surgery than what Phantom Neuro describes. The Phantom X procedure appears to occupy a different tier: subcutaneous placement without bone involvement, under local or regional anesthesia, in a roughly hour-long outpatient slot. Whether that tradeoff, less invasive but also potentially less signal richness than deeper interfaces, proves useful in practice is one of the things the CYBORG study is designed to answer.

What the study is not: it is not a randomized trial, not a pivotal study, and not evidence of approved clinical effectiveness. Early feasibility studies enroll small numbers of participants to evaluate whether a device can be placed safely and whether it does, in a preliminary way, what it is designed to do. Results from this phase will inform whether and how the company pursues further development.

What this means

If you have upper-limb loss and have found surface myoelectric control unreliable due to socket fit or skin factors, this research direction is worth following. No timeline exists for commercial availability, and the company has not named the prosthetic devices Phantom X currently integrates with.

The CYBORG study is ongoing. Phantom Neuro has not published results. When data from this study appear in peer-reviewed form, that will be the moment to assess whether the approach delivers on the premise.

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This article describes a clinical research study. Phantom X is an investigational device and is not available outside of clinical trials. Nothing here constitutes medical advice about prosthetic device selection. Speak with your prosthetist and physician about options appropriate for your specific situation.