CHICAGO -- The biggest thing in operating rooms these days is a million-dollar, multiarmed robot named da Vinci, used in nearly 400,000 surgeries nationwide last year -- triple the number just four years earlier.But now the high-tech helper is under scrutiny over reports of problems, including several deaths that may be linked with it, and the high cost of using the robotic system.There also have been a few disturbing, freak incidents: a robotic hand that wouldn't let go of tissue grasped during surgery and a robotic arm hitting a patient in the face as she lay on the operating table.Is it time to curb the robot enthusiasm?Some doctors say yes, concerned that the "wow" factor and heavy marketing are behind the boost in use. They argue that there is not enough robust research showing that robotic surgery is at least as good or better than conventional surgeries.Many U.S. hospitals promote robotic surgery, partly to attract business that helps pay for the costly robot.Almost 1,400 U.S. hospitals -- nearly 1 out of 4 -- have at least one da Vinci system. Each one costs about $1.45 million, plus $100,000 or more a year in service agreements.The da Vinci is used for operations that include removing prostates, gallbladders and wombs, repairing heart valves, shrinking stomachs and transplanting organs. Its use has grown worldwide, but the system is most popular in the United States."We are at the tip of the iceberg. What we thought was impossible 10 years ago is now commonplace," said Dr. Michael Stifelman, robotic surgery chief at New York University's Langone Medical Center.For surgeons, who control the robot while sitting at a computer screen, these operations can be less tiring. Plus robot hands don't shake. Advocates say patients sometimes have less bleeding and often are sent home sooner than with conventional laparoscopic surgeries and operations involving large incisions.But the Food and Drug Administration is looking into a spike in reported problems. Earlier this year, the FDA began surveying surgeons using the robotic system. The agency conducts such surveys of device use routinely, but FDA spokeswoman Synim Rivers said the reason for it now "is the increase in number of reports received" about da Vinci.Reports filed since early last year include at least five deaths.