Conjoined twins Jadon and Anias McDonald are doing better than expected after a 27-hour surgery last month to separate their skulls, the New York doctor treating the boys said Wednesday. The McDonald twins were joined at the head as craniopagus twins.

The lead neurosurgeon for their case told CNN that the children are progressing "right on target, if not ahead of schedule." Both boys have had their breathing tubes removed since the operation. 

"As a neurosurgeon, I guess it puts you in a happy mood," said Dr. James Goodrich, who led the operation at the Children's Hospital at Montefiore Medical Center in the Bronx.

Jadon suffered a partial paralysis of his left side after the surgery, but later regained full functionality. Anias suffered seizures after the surgery. Jadon's vitals remained stable during the surgery, but Anias struggled throughout the operation when his heart rate and blood pressure dropped significantly.

"I don't think that is going to be a long-term issue with him," Goodrich told CNN about Anias' seizures.

Goodrich also said that the twins are doing so well that he hopes that in the coming weeks, "we'll have them both out of here, off to rehab."

One-third of craniopagus twins die within 24 hours of birth. However, the boys were 13-month-old at the time of their surgery. Cases of twins born conjoined are reportedly rare, occurring one in every 200,000 births.

Late in October, the mother of the conjoined children, Nicole McDonald, was finally able to hold her son Jadon for the first time since the surgery. 

“I looked down at Jadon’s angelic face and saw him in a way I’d never seen him before. He whimpered for almost the whole two hours I held him because he had just been extubated, had the area under his scalp washed out and had been weaned from the good pain meds,” Nicole wrote in a Facebook post at the time.