Phantom Neuro implants its under-the-skin muscle sensor for prosthetic arms in its first patients

Austin-based Phantom Neuro announced on October 20 that the first people with upper-limb loss have received its Phantom X implant, in the company’s CYBORG early feasibility study at Cabrini Health in Melbourne, Australia. IEEE Spectrum reports that two participants have been implanted so far. Plastic surgeon Michael Lo performed the procedures, which the company describes as outpatient operations of about an hour without general anesthesia; IEEE Spectrum notes the first took longer, with the second around 45 minutes.

How it works

Phantom X is a flexible strip, about 2 by 10 centimeters, placed under the skin over the muscles of the residual forearm. Two rows of electrodes pick up the electrical activity (EMG) that muscles produce when the person tries to move the fingers and wrist of the missing hand. An electronics unit at one end processes these signals and sends them wirelessly to a compatible prosthetic arm, and power is delivered from outside the body through a coil, similar to a cochlear implant.

Most myoelectric prostheses today read muscle signals with electrodes on the skin surface. These can shift, are affected by sweat and movement, and often need frequent recalibration. Phantom’s approach places the sensor under the skin without going into the brain or the nerves. Australian regulators approved the study in April, and the company told IEEE Spectrum it hopes for US approval in two to three years.

Why it matters

• It is a less invasive route to more reliable prosthesis control, aimed at the many people with limb loss who would not consider brain or nerve surgery.
• The study is small and early: it is assessing safety, performance and usability, and the device is investigational. The company says conclusions about safety and control will need further evaluation, and the implant cannot yet combine movements smoothly.

Learn more: EMG · Neuroprosthetics · Phantom Neuro in the Directory