The remaining medical obstacle to the departure of the deposed shah of Iran from the United States today apeared to have been removed by the successful extraction of a stone that had been blocking his bile duct.

The stone was crushed to permit the extraction of "several fragments" during a 45-minute non-surgical procedure conducted late Monday night, according to a statement released by New York Hospital-Cornell Medical Center, where the shah has been a patient since Oct. 22.

The shah, Mohammad Reza Pahlavi, who is suffering from cancer of the lymphatic system, has been reported by his aides to be eager to return to his Mexican exile home to help ease the crisis in U.s. iRan relations that began Nov. 4 when students seized the U.S. Embassy in Tehran. demanding that the shah be returned to Iran for trial.

Travel had been ruled out by the shah's doctors as long as the stone, which they had not reached during the Oct. 24 surgical removal of several other stones and his gallbladder, stayed lodged in the bile duct.

However, the hospital hedged on the question of when the shah would be able to leave, because a possibility remains that some pieces of the stone were not removed.

"Further studies will be conducted during the next few days to determine if any fragments of the stone or [any infection] recurs. The prognosis remains guarded," the statement said.

Hospital sources noted, however, that as far as his gallbladder removal and bile duct treatment were concerned -- and excluding consideration of his cancer -- the shah was in good condition.

The shah suffered from an infection of the bile duct and a fever of just under 104 over the weekend, but responded well to antibiotics and has no fever now doctors said.

Dr. H. Joachim Burhenne flew into New York from Vancouver, B. C., to extract the stone through a process he pioneered in 1973.

Burhene's procedures involves the insertion of a tiny wire basket through a long tube in the direction of the stone. the radiologist in charge monitors the progress of the tube on a fluoroscope and at the right moment pushes the basket out the end to grasp the stone.

The procedure is painless and is performed without anesthesia. In the shah's case, a channel for the procedure had been formed by a tube left behind during an earlier operation.

Burhenne could not be reached today, but he said before flying to New York that he had successfully performed the procedure 800 times. He claimed an 80 percent success rate for his technique, but added that it could not be attempted within five weeks of an operation to enable the channel to become firm for insertion of the tube. The shah's operation was performed five weeks ago Wednesday.

Burhenne, professor and head of the Department of Radiology at the University of British Columbia, was assisted by radiologists from New York Hospital and Cornell Medical Center.

The hospital statement said the shah's bile duct stone was found where expected. Apparently, however, it was too large to be extracted in one piece, and therefore had to be crushed while still in the duct.

The shah's radiation therapy for the lymphoma in his neck has been completed with only the expected side effects of soreness in his throat, the statement continued. His treatment was on Thanksgiving.

When the shah came to New York in October, his doctors said they wanted to treat his cancer over an extended period -- perhaps 18 months. However, chemotherapy, which seems to be the next indicated step in his recovery, could be administered elsewhere.