A former Columbia University gynaecologist Robert Hadden has been sentenced to 20 years in prison after being convicted of sexually assaulting dozens of women out of his Manhattan medical offices.

The 64-year-old will serve the sentences concurrently, for a total of 20 years – rather than consecutively, which would have meant a total of 80 years in prison – followed by supervised release for the rest of his life.

“This case is like no other in my experience in terms of horrendous, beyond extraordinary, depraved sexual assault,” said Judge Richard M. Berman. “Unquestionably outside the guidelines of the sentencing range.” More than 200 patients received a cut of the more than $236 million in settlement funds for Hadden’s conduct.

Hadden, of Englewood, New Jersey, started abusing women soon after he started working in 1987 at Columbia-Presbyterian Medical Center in New York, which later became New York-Presbyterian Hospital.

Trial evidence proved Hadden committed anywhere from 167 to 310 acts of sexual abuse or assault on dozens of patients as he honed his abuse techniques so the assaults would go undetected for over 20 years, prosecutors wrote in a presentence submission.

Prosecutors said he sought sexual gratification when he asked victims “detailed, inappropriate, and medically unnecessary questions and provided unsolicited advice and commentary about their bodies, pubic hair, masturbation, sexual activity, sex toys, pornography, and sexual partners.”