Reports of complications from robot-assisted surgery are rising, according to Massachusetts health officials who sent hospitals an “advisory” letter last week alerting them about their safety concerns.

In some cases, it appears that doctors have used the aggressively marketed robots to perform hysterectomies and colorectal operations that were too complex for the technology, or for the surgeons’ skill level in directing the robots’ actions.

During one hysterectomy, two surgeons failed to coordinate their movement of the remote-controlled robotic arms, damaging the patient’s bowel and causing excessive bleeding, according to the letter from the Quality and Patient Safety Division, part of the agency that licenses Massachusetts doctors.

In another hysterectomy, a woman was anesthetized and placed for nearly four hours in a steep head-down angle — a position often used during robotic operations. She suffered shoulder injuries. The advisory described a number of mishaps but did not identify the doctors or hospitals involved.

Robotic surgery — in which doctors sit at a video console and remotely move robotic arms holding surgical instruments and a tiny camera — has surged in popularity for prostate operations and other procedures. That’s partly because the manufacturer and hospitals heavily advertise the technology as reducing complications and speeding recovery.

Brigham and Women’s Hospital last fall allowed shoppers to “test drive” a robot outside Macy’s at the Natick Mall, by sitting at the console and manipulating the arms. Community hospitals have jumped on the bandwagon, too. St. Luke’s Hospital in New Bedford, Mass., invited the public to get behind the controls of its new robot in January, while others including Beth Israel Deaconess Hospital Milton have erected highway billboards.

The hospitals now say they are reviewing some of their marketing activities.

The patient safety division urged hospitals to make sure that surgeons are proficient in robotic surgery before allowing them to operate and that doctors carefully screen patients for risk factors. It also advised hospitals to establish multi-disciplinary committees to monitor results of the surgeries.

Patient injuries during robotic surgery have grown over the past two years, the division said, but it would not provide the data. The advisory comes amid a growing number of patient lawsuits nationally, some of which allege doctors inexperienced with the robot took so long to complete operations that patients suffered nerve and other injuries from the anesthesia or from the angle of the operating room table.

“The marketing is not based on any data,” said Dr. Peter Dunn, director of perioperative services at Massachusetts General Hospital. “This tool was brought to us — by the manufacturer — solely as a marketing device. The medical community didn’t do what it should have done — say, ‘Wait a minute, hold on.’”

Surgeons who are enthusiastic about the technology say it allows them to operate with more precision. The robotic arms move in more directions than the human wrist, and the machine’s software smooths out small hand tremors. Images on the video screen are also highly magnified, allowing the surgeon a better view of the patient’s anatomy. They also tend to be less invasive.

Still, proof that these advantages lead to better results has been elusive. In January, a national medical safety organization, the ECRI Institute in Pennsylvania, concluded based on an analysis of relevant studies that robotic surgery is booming despite limited evidence that it works better than standard operations.

Intuitive Surgical Inc. of California, the manufacturer of the da Vinci robot — the only surgical robot on the market — disputes that assertion.

“Numerous peer-reviewed studies including large population studies have demonstrated lower complication rates and mortality rates compared to open surgery,” company spokesman Geoff Curtis said in a written statement to the Boston Globe.

Curtis called the state advisory “balanced” and said the company “agrees with the report’s conclusions.”

“We think these key points align with our mission to improve surgical outcomes for patients.” he said.

Marketing changes

The state’s advisory recommended that hospitals pay attention to whether direct-topatient marketing changes how they select patients, given that such advertising has led patients to seek out the procedure from their doctors. It also cautions hospitals to make sure their websites include the risks as well as the benefits of robotic surgery. Few do, according to a Globe sampling.

The Brigham said it plans to change its website promotion of robotic surgery to reflect the recommendations, while Milton Hospital and Southcoast Health System, which includes St. Luke’s, are considering adding information on risks.

Dunn said that patients undergoing robotic surgery to remove cancerous prostates are surprised when they experience complications because hospitals have been so positive about the technology.

“It’s just that the complications are different” from those more common in traditional surgery, he said. “They’re idiosyncratic. For example, your instruments may be out of your field of view so you may injure another organ.”

Urologists urged Mass. General to buy a robot in 2007, Dunn said, because they were fielding calls from interested patients. The hospital purchased one but has decided not to advertise it, he said.

Dr. Jim Hu, a surgeon at UCLA Medical Center in Los Angeles who has researched robotic surgery, said the da Vinci has been used in prostate cancer surgery since 2000. Complications were high in the early days as surgeons learned how to use the robot, he said, but have since leveled. As surgeons expand their use of the robot to other surgeries, patient injuries may be rising again, he said.

In 2008, more than half of all robot-assisted surgeries were for prostate cancer. Now, hysterectomies are the fastest-growing type of robotic surgery, comprising about 40 percent of operations, according to ECRI.

Still, just because surgeons have more experience with robot-assisted prostatectomies does not mean patients necessarily experience better results than with traditional surgery.

In fact, a study Hu led while he was at the Brigham in 2009 found that cancer patients who underwent minimally invasive prostate removal with the robot were more than twice as likely to experience incontinence or impotence a year and a half after their operations than patients who had traditional surgery using an open incision, though the overall risk was still small in both cases.