He was one of the first doctors to employ endoscopy in gynecological practice, in which a small optical instrument called an endoscope is used to examine areas tucked deep into the body.
[2] One of Neuwirth's greatest priorities was lessening the need for hysterectomy, a common gynecological surgical procedure that removes the uterus while often posing significant risks of infection and other severe complications.
The surgical discipline of gynecological endoscopy, which Neuwirth pioneered, utilizes optical instruments to help diagnose common female-specific disorders and pathologies, including but not limited to infertility and vaginal hemorrhaging.
Neuwirth is credited as the first doctor to introduce laparoscopy to the United States in 1968, authoring several research articles on laparoscopic sterilization and ovarian biopsies.
In 1992, Neuwirth authored the first report on long-term outcome of menstrual function following hysteroscopic endometrial ablation, a treatment for abnormal uterine bleeding.