Neuralink Corp, the brain-implant company founded by Elon Musk, was set to implant its device in a second patient last Monday (June 24), but the surgery was halted due to the patient’s medical condition, said Michael Lawton, chief executive officer of the Barrow Neurological Institute.

The patient had health issues that made the person an unsuitable candidate for current participation in Neuralink’s study of its experimental device, Lawton said during a phone call. A replacement candidate will likely undergo the surgery next month at the Barrow facility.

"Selecting the right patient for a trial like this is important,” Lawton said. "Everybody involved, clinically and surgically, wants to get it right.”

Neuralink didn’t respond to an emailed request for comment.

The startup is in the early stages of clinical trials for its device, which is aimed at restoring function to paralysed patients. An Arizona man, Noland Arbaugh, recently became the first human patient to have the device implanted. A quadriplegic after a 2016 injury to his spinal cord, Arbaugh can now successfully play video games using his thoughts.

The patient whose surgery was cancelled this week has amyotrophic lateral sclerosis, also known as Lou Gehrig’s disease, which causes nerve cells in the spine and brain to degenerate. Ultimately, muscles become paralysed.

Patient privacy rules prevent the release of further information about the patient.

Testing the device on patients with different causes of motor impairment is useful, said Cristin Welle, an associate professor of neurosurgery at the University of Colorado and a former US Food and Drug Administration official.

"It can be valuable to know it works across different conditions,” Welle said. Plus, the Neuralink researchers have a wider pool of patients to recruit from.

Barrow was the site where Arbaugh underwent his surgery in January. Based in Phoenix, the facility treats patients with complex neurological conditions. Neuralink President DJ Seo praised Barrow in April as moving "with lightning speed to deliver quality care for their patients.”

 - Bloomberg