More complex and expensive surgeries in January helped St. John’s Medical Center continue its positive financial trend.

The hospital posted a 12 percent gain in gross revenue compared to the same month last year.

St. John’s revenue increased despite a decrease in the number of surgery patients and the amount of time they spent under the scalpel.

Hospital Chief Financial Officer John Kren pointed to the involvement of the cases as the reason for the strong financial showing.

“The types of cases that we did this January as compared to last January just so happened to be more complicated, meaning highly acute, inpatient cases,” Kren said.

Procedures related to spines, shoulders and hips, for example, tend to be more costly, he said.

Patient days were on par with last year’s totals, but the number of people who stayed overnight in the intensive care unit nearly doubled.

Admissions to the ICU increased 85 percent, from 13 to 24.

Patients are also continuing to stay in town for orthopedic surgeries rather than traveling to Idaho or Utah, hospital officials have said. That trend continued last month.

“There was a year over year increase in the number of orthopedic surgeries which contributed to an increased usage of costly implant materials,” Kren wrote in the monthly finance report.

St. John’s logged 105 orthopedic surgeries in January of 2012 and 120 this year.

The financial success of the tax-subsidized hospital continues a positive trend that has persisted since last spring.

January’s haul pushed St. John’s to $74.4 million in gross revenue thus far through the fiscal year, up from the budgeted amount of $64.4 million and last year’s total of $60.7 million.

The biggest hike continues to be in inpatient money, which came in 39 percent ahead of budget for the month and now totals $32.2 million on the year, compared with a projected $26.4 million.

Operating income has reached $5.2 million so far. St. John’s finished the last fiscal year, which ended in June 2012, with $3.7 million.

But hospital officials have warned that the positive trends may not last, especially in light of the uncertainties brought on by the Patient Protection and Affordable Care Act and, specifically, reductions in Medicare reimbursements.

Chief Executive Lou Hochheiser said at a board meeting last week that sequestration could lead to a slower summer.