In what is believed to be a world first, surgeons have removed a healthy kidney via a small incision in the back of the donor's vagina.

The operation, known as a transvaginal donor kidney extraction, was performed on a 48-year-old woman who was donating a kidney to her niece.

The surgery took place on Jan. 29 at Johns Hopkins Medicine in Baltimore, Md., and both patients are reported to be doing well.

For the procedure, surgeons send two wand-like tools through small incisions in the abdomen, while a third flexible tool with a camera is placed in the navel.

Video images from the camera guide the surgeons through the procedure. Once the kidney is cut from the abdominal wall, the surgeons place the kidney in a plastic bag that is inserted through an incision in the vaginal wall. The bag is then pulled through the vaginal opening by an attached string.

The surgery takes about three-and-a-half hours, which is about the same amount of time as a traditional kidney-removal procedure.

The operation has been done before to remove cancerous or non-functioning kidneys, but never for a healthy kidney donation.

The procedure is designed to avoid the 12 to 15 centimetre abdominal scar that kidney removal surgery leaves behind. The new operation left the donor will three pea-sized scars on her abdomen.

"(The large) incision is thought to significantly add to the patient's pain, hospitalization and convalescence," surgery team leader Dr. Robert Montgomery, chief of the transplant division at Johns Hopkins Medicine, said in a statement. "Removing the kidney through a natural opening should hasten the patient's recovery and provide a better cosmetic result."

Transvaginal kidney extraction is part of a new set of surgical procedures known as natural orifice translumenal endoscopic surgeries (NOTES), whereby surgeons use a natural orifice to remove organs and other tissues.

Since 2004, NOTES have included removing diseased gallbladders and appendixes through the mouth, and gallbladders, kidneys and appendixes through the vagina.

In addition to less pain and shorter recovery time, Montgomery said the surgical team hopes that the minimally invasive procedure will make people more willing to become organ donors.