"You can also run into problems such as infection or extrusion, which happens when the silicone comes out through the skin," said Dr. Liza C. Wu, assistant professor in the Division of Plastic Surgery at the University of Pennsylvania.
Problems can arise from using the body's own tissue as well.
"This kind of reconstruction can be more complicated, and the biggest problem is failure," said Wu.
"There could be a problem with circulation into the flap, which is the tissue moved from one part of the body to the other," said Garfein. "When you plug the blood vessels from the other tissue into the neck, there could be a problem with the artery that brings blood in and out of the flap."
Cancer specialists say it's extremely rare for thyroid cancer to cause complications as serious as losing the voice or requiring reconstructive surgery.
"That's extreme to the point of being almost unheard of," said Dr. Robert Udelsman, chair of the Department of Surgery at the Yale University School of Medicine in New Haven, Conn. "It's possible to spread, but that's more than a little unusual."
Udelsman said the majority of people with thyroid cancer are cured. The most common type of thyroid cancer is papillary thyroid cancer, the type Ebert had.
"The papillary form probably accounts for about 75 percent of all thyroid cancers, and the vast majority are cured," he said.
Treatment often involves surgically removing the entire thyroid. Surgery can be tricky, Udelsman said, and occasionally the vocal cord nerves can be damaged.
Ebert had surgery to remove cancer from his salivary gland in 2003, but as he said in his journal, his surgery didn't go well.
"What happened was, cancer of the salivary gland spread to my right lower jaw. A segment of the mandible was removed. Two operations to replace the missing segment were unsuccessful, both leading to unanticipated bleeding," Ebert wrote.
According to the National Cancer Institute, cancer of the salivary gland is rare and treatment can include surgery, depending on the stage and aggressiveness of the cancer.
Ebert says he has no problem showing off his new look.
"I accept the way I look. Lord knows I paid the dues," he wrote.
ABC News' Lauren Cox and Ki Mae Heussner contributed to this report.