FDA Investigates Robotic Surgery System After Adverse Event Spike

April 30, 2013

A spike in the number of adverse event reports (AERs) associated with the da Vinci Surgical System (Intuitive Surgical) last year has prompted the US Food and Drug Administration (FDA) to survey surgeons about their experience with this technology for robot-assisted surgery.

Some of the AERs on file with the FDA pertain to equipment malfunctions that resulted in no harm to patients during operations that ranged from hysterectomies to coronary artery bypass graft surgery. Other reports describe injuries and deaths, although they are not necessarily blamed on an equipment problem. In some cases, surgeons who operated robotic arms and the various tools attached to them punctured bladders, severed nerves and blood vessels, and otherwise appeared responsible for the mishaps.

In other cases, the da Vinci surgical robot seemed to have a life of its own, at times inexplicably cauterizing a fallopian tube, damaging heart tissue, or refusing to let go of a patient's tissue with its grasper. "We had to do a total system shutdown to get the grasper to open its jaws," stated one report, noting that the patient was not injured.

The number of AERs for the da Vinci Surgical System filed with the FDA's Manufacturer and User Facility Experience (MAUDE) database increased 34%, going from 211 in 2011 to 282 in 2012. During that period, the number of procedures performed with the da Vinci system in the United States increased 26%, going from 292,000 to 367,000, according to a quarterly report that Intuitive Surgical filed earlier this month with the US Securities and Exchange Commission (SEC).

Through the first 3 months of 2013, MAUDE received 62 reports, putting the robot-assisted surgery technology on track to amass 248 AERs this year. Many AERs are filed by the manufacturer itself. Other reports come from hospitals, clinicians, and patients.

Table. Spike in AERs on the da Vinci Surgical System

Year No. of da Vinci Procedures in the United States Change No. of AERs Filed With FDA Change
2012 367,000 26% 282 34%
2011 292,000 28% 211 −2%

Source: Intuitive Surgical SEC filing; FDA MAUDE database

In January 2013, the FDA asked surgeons whose hospitals belong to the agency's Medical Product Safety Network to participate in a 10-question telephone survey about the da Vinci Surgical System. Surgeons were asked, among other things, about user training, common equipment repairs, patient selection, the complications they saw and how they compared with those seen in conventional surgeries, and what procedures are the best and least suited for the da Vinci technology.

FDA spokesperson Synim Rivers told Medscape Medical News that the FDA conducted the survey "after we observed an increase in the number of reports we received about the da Vinci Surgical System." An upward trend in AERs, Rivers said, does not necessarily mean that a medical device is faulty. Sometimes, upswings occur because more clinicians are using the device.

Increased publicity sparked by lawsuits or product recalls also can boost the number of AERs, "but this does not necessarily indicate a true rise in event occurrence," said Rivers. In addition, the reports may contain false, incomplete, or duplicative information. Accordingly, they cannot be construed to "establish or compare rates of event occurrence."

"Since it is difficult to know why the reports have increased, FDA has elected to talk with surgeons," said Rivers. Such a survey is "a routine part of [medical device] surveillance."

"Excellent Safety Record," Manufacturer Says

Geoff Curtis, a spokesperson for Intuitive Surgical, also told Medscape Medical News that the survey of surgeons is part of the FDA's routine and ongoing monitoring of approved products.

Asked about the increase in AERs filed with the FDA, Curtis reiterated a point made last month in a company press release — that an increase in AERs submitted by Intuitive Surgical reflects a change in reporting practices, not a change in product performance.

In September 2012, the company began reporting certain device malfunctions — such as cable breaks — that had not been submitted before, said Curtis. "None of these involved reportable injuries or deaths."

According to the MAUDE database, the rate of AE reporting about the da Vinci Surgical System slowed down during the last 4 months of 2012. During the first 8 months of the year, 204 AERs were filed, or 25.5 per month. Seventy-eight reports followed from September through December, for a monthly rate of 19.5. Curtis said it is possible that the database has not been updated yet to reflect the increase in company-submitted AERs.

Overall, Curtis said, the da Vinci technology "has an excellent safety record, with more than 1.5 million surgeries performed globally, and total adverse events have remained low and in line with historical trends."

The company, he said, has investigated all the AERs, including those that describe involuntary movement of robotic arms and surgical instruments. "To date, there have been no confirmed incidents where the computer went out of control to produce an unintended motion," Curtis said.

Second Thoughts About Robot-Assisted Surgery

Robot-assisted surgery is similar to traditional laparoscopic surgery except that surgeons do not wield the tools of their trade inside a keyhole incision with their hands. Instead, they use hand and foot controls to manipulate instruments attached to robotic arms.

Intuitive Surgical touts "da Vinci surgery" on its Web site as combining the benefits of minimally invasive laparoscopic surgery with "the 'look and feel' of open surgery." With a robot assistant, the company says, surgeons now can take a minimally invasive approach to procedures such as mitral valve repair and prostatectomy that are deemed too complex for ordinary laparoscopic surgery.

A da Vinci Surgical System costs between $1 million and $2.3 million, depending on its configuration and the local market, according to Intuitive Surgical. As of March 31, a total of 1957 da Vinci Surgical Systems were installed in the United States compared with 1091 at that time in 2010, according to company reports filed with the SEC.

The FDA survey on the da Vinci Surgical System comes at a time of second thoughts about the value of robot-assisted surgery in general. A study published in February in JAMA reported that robot-assisted hysterectomy posted complication rates similar to those for laparoscopic hysterectomy but cost almost $2200 more per procedure.

In March, the American College of Obstetricians and Gynecologists (ACOG) issued a statement declaring that "robotic surgery is not the only or the best minimally invasive approach for hysterectomy. Nor it is it the most cost-efficient." If technically feasible, vaginal hysterectomy remains the procedure of choice because it is the "least invasive and least expensive option," the college stated. "When this approach is not possible, laparoscopic hysterectomy is the second least invasive and costly option for patients."

ACOG advised clinicians to reserve robot-assisted hysterectomy "for unusual and complex clinical conditions in which improved outcomes over standard minimally invasive approaches have been demonstrated."

That same month, the Massachusetts Board of Registration in Medicine issued an advisory on robot-assisted surgery in response to what it called a growing number of reported patient complications. The state medical board recommended that healthcare facilities take greater pains to credential surgeons, train surgical support staff, select appropriate patients, and explain the risks to them.

"Patients should be advised on the experience of the surgeon in performing the recommended robotic procedure," the board said.

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