Dr. Marty Immerman won't get to take off early from work this New Year's Eve. The Edina ob/gyn is performing a tubal ligation on Dec. 31 for a patient who simply had to get in before the end of the year. He's not the only doctor who is busier than usual this holiday season.

Abbott Northwestern Hospital Minneapolis is doing a record number of surgeries. And doctors at Minnesota Gastroenterology are doing 14 percent more procedures -- mostly colonoscopies -- in November and December than at the same time a year ago.

What gives?

It's the Year-End Mini-Boom, a new phenomenon brought on by health insurance plans with deductibles. It appears to work like this: Early in the year, patients are more likely to hold off getting care because they are paying out of pocket. Later in the year, some have paid enough to reach their deductible and insurance kicks in.

At that point, insurance covers most medical services -- whether at 80 percent, 90 percent or completely -- until the deductible resets in the new plan year, Jan. 1 for most of them.

That's the time to cram in colonoscopies, hysterectomies, hernia surgeries and knee replacements.

It used to be just Medicare patients with deductibles clamoring to get in at year-end, said Mary Igo, chief executive of Minnesota Gastroenterology. "Now it's everybody."

At a time when the weak economy is hurting the industry, medical groups say they are grateful for the bump in business, however temporary. To cope with demand, doctors are adding hours and delaying vacations.

High-deductible plans with health savings accounts were introduced in 2004 and now cover about 10 percent of insured Minnesotans. At the same time, deductibles for traditional plans -- known as preferred provider organizations -- also have jumped, with a $1,000 deductible now the national norm, according to benefits consultant firm Mercer.

The deductibles have helped slow the growth of medical spending, as people think twice before seeking care.

Less predictably, they're also creating a year-end frenzy to get in to see the doctor.

To be sure, not all medical providers are enjoying a year-end boost.

At Minnesota Eye Consultants, a large eye care group, business usually is slow in winter as older patients fly to Florida or Arizona. That hasn't changed.

And at many hospitals, business is down because of the economy. Park Nicollet Health Services, which owns Methodist Hospital in St. Louis Park, said it is not seeing its typical year-end rush of patients.

Fourth quarter is the busiest

But at Paul Larson OB/Gyn Clinic in Edina, the fourth quarter now is the clinic's busiest. At Abbott Northwestern Hospital, December surgeries have surpassed all records, said Dr. Bob Wieland, vice president of medical affairs.

"The wave of last-minute surgeries rode on top of a busy acute illness period for us," he said. "Surgeons are operating later into the night."

Back in the fall, when the economy started tanking, Abbott noticed a drop in patients. Wieland thinks some people, not wanting to miss work at a time when their employers might be mulling job cuts, delayed elective procedures as long as they could.

Now "the rush is all compressed [into] December," he said.

Glitter and hard work

In a Coon Rapids medical building last week, there were shiny, gift-wrapped boxes on the walls and a Christmas tree in a corner. But the mood at Minnesota Gastroenterology was all business. The waiting room was full and four doctors were working that day, compared with the usual one or two.

Doctors at the practice's five locations started noticing a change in seasonal business two years ago.

In 2006, a rash of cancellations early in the year indicated that something was up. But the mysterious drop in demand didn't recur in early 2007.

Igo thinks patients whose health insurance had changed were figuring out their deductibles and what was covered and what wasn't.

(Colonoscopies often are covered as part of preventive care, although patients may not always know that. But if a physician finds something, it is then regarded by insurers as treatment and not prevention, and must be paid for out of pocket, counting toward a deductible.)

Then came the year-end rush. To cope, the practice added 15 extra physician days this year, or the equivalent of 225 extra procedures.

About half of Dr. Philip Lowry's patients who needed colonoscopies asked him to get them in before the end of the year. Lowry has been working an extra hour or two as needed to fit them in.

Another doctor, Dr. Neville Basman, postponed a family vacation to Israel to work three extra days last week, including Christmas Eve.

Chen May Yee • 612-673-7434