In this story:

• Donor was a brain-dead patient
• New drugs aided operation

LYON, France (CNN) -- An international team of surgeons is optimistic about an experimental hand-and-forearm transplant operation performed on a man whose own arm was amputated 14 years ago.

The 48-year-old businessman, Clint Hallam, underwent Wednesday's delicate 13.5-hour surgery at the Edouard Herriot hospital in Lyon in central France. Hallam lost his hand in a circular-saw accident in 1984.

Doctors say there's a 50-50 chance that the transplanted limb will not be rejected by his body, partly because of new drugs that are better able to control the body's immune system, which rejects foreign cells.

The surgical breakthrough "gives hope to millions of victims of workplace and domestic accidents, survivors of war or land mines and individuals born with hereditary deformities," said Dr. Jean-Michel Dubernard, who led the surgical team.

Hallam told doctors he was "over the moon," Dubernard told French television LCI. Hallam lives in Perth, Australia.

"He is in excellent shape," Dubernard said. "A day after the surgery, the grafted hand is warm and has taken on color."

Donor was a brain-dead patient

The doctors followed the same procedures routinely used for reattaching a patient's own limb. Hospital officials said the donor was a brain-dead patient.

The complex operation required the setting of two bones in the arm followed by painstaking attachments of a half dozen blood vessels and nerves, and nearly two dozen tendons that control movement of the wrist, fingers and thumb.

Plastic surgery is required to combine muscle and stitch together the several layers of skin.

Dr. Xavier Martin said the next month will be critical in determining whether the transplant will survive or be rejected by Hallam's immune system.

New drugs aided operation

If the transplanted hand does survive, doctors say it'll be 12 months to 18 months before Hallam regains sensation and control. They expect him to be able to grasp with the hand, but are less sure about fine movements of the fingers.

Doctors said the technical skills required to carry out the procedure have been in place for years. But the operation never was tried before, because of the danger the body would reject the graft.

The medical team included experts in microsurgery, orthopedics and transplant surgery from France, Australia, Britain and Italy.

Led by Dubernard of Lyon and Earl Owen of Sydney, Australia, the team also included Briton Nadey Hakim, Italian Marco Lanzetta, Australian Hari Kapila and Frenchmen Guillaume Herzberg, Marwan Dawahra and Martin.