With a dramatic assist from Sen. Edward Kennedy, Senate Democrats pushed through a long-delayed bill that prevents a 10.6 percent cut in fees for doctors serving Medicare patients.

Kennedy returned to the Senate chamber for the first time since critical surgery for a malignant brain tumor last month and cast a crucial vote this afternoon on a stalled Medicare bill opposed by the White House. The measure gained lopsided 355-59 approval in the House last month and now moves to the White House, where President George W. Bush has threatened a veto.

The measure finances the higher doctor payments by shaving $13 billion from Medicare Advantage insurance programs. It also includes benefits for mental health and low-income programs and boosts quality through national e-prescribing. It has been heavily lobbied by a coalition of health interest groups, including the American Medical Association and AARP.

The surprise appearance of the 76-year-old Massachusetts senator had been rumored. But when Kennedy actually entered the chamber, he was greeted by cheers and thunderous applause. His vote was part of a bipartisan, 69-vote majority that overcame a procedural hurdle. The measure was then approved on a voice vote.

AARP CEO Bill Novelli praised the Senate vote. “They say that life doesn’t give you second chances. The Senate got a big one this week, and AARP applauds the bipartisan majority of senators who voted to pass a bill that would protect and improve Medicare for the 44 million Americans who depend on it.

“We hope the president recognizes the overwhelming bipartisan support that passed this bill in both chambers of Congress and signs it into law.”

The bill stalled two weeks ago, before the Senate’s July 4th recess, when the Senate failed by one vote to break a Republican-led filibuster. Senate Majority Leader Harry Reid, D-Nev., warned Republicans then that “We’ll be back, and you’ll have another opportunity to vote for this. During the next 10 days, think about how you’re going to vote on this next time.”

During the days that followed, Senate offices were bombarded by constituent calls and e-mails urging them to pass the bill.

Some 600,000 doctors care for Medicare patients. Payment rates were set to drop by 10.6 percent on July 1 as a result of a formula that calls for cuts when spending exceeds established goals. Avoiding the cuts has become an annual event for Congress, but finding the money invariably requires trimming payments to other health care providers.

Democrats this year focused on taking the money from the Medicare Advantage program, which lets older and disabled people get their health benefits through a private insurer rather than through traditional Medicare.

Democratic lawmakers say the government’s payments to the insurers are overly generous, but the administration and supporters in Congress say they translate into lower monthly premiums for Medicare Advantage participants or extra services such as vision and dental care. Under the bill, insurers would lose $13 billion over five years.