OAKLAND, Calif. - An Oakland judge Monday appointed a Stanford doctor independently evaluate the brain activity of a teenager who has been on life support since complications developed during a tonsillectomy.

Superior Court Judge Evelio Grillo appointed Dr. Paul Fisher -- the Chief of Pediatric Neurology at Stanford Children’s Hospital – to carry out the independent review of the case.

Grillo also extended the temporary restraining order requiring Children Hospital Oakland to keep 13-year-old Jahi McMath on life support.

“We are sorry that Jahi McMath suffered tragic complications from her complex surgery. Our hearts go out to the grieving family and community about this sad situation,” said Dr. David Durand, Chief of Pediatrics at Children’s Hospital, in a prepared statement. “We look forward to the independent expert’s evaluation of the patient. The Chief of Pediatric Neurology at Stanford Children’s Hospital, Dr. Paul Fisher, is a known expert on brain death and has performed many such examinations.”

“Both the State Department of Public Health and the hospital are investigating this matter,” he continued. “ The hospital is committed to learning what led to this catastrophic outcome.”

But Durand also said he did not want to give the family false hope.

“We have the deepest sympathy for Jahi's mother who wishes her daughter was alive; but the ventilator cannot reverse the brain death that has occurred and it would be wrong to give false hope that Jahi will ever come back to life,” he said in the statement.

The family said the girl bled profusely after a routine tonsillectomy. She then went into cardiac arrest before being declared brain dead Dec. 12.

The teen's mother, Nailah Winkfield, over the weekend pleaded for prayers for her daughter.

"Despite what they say, she is alive. I can touch her, she is warm. She responds to my touch," Winkfield said in an open letter Saturday. "Given time I know (God) will spark her brain awake."

Winkfield said her daughter bled profusely and went into cardiac arrest after undergoing a "simple procedure" to remove her tonsil to help with her sleep apnea.