Surgical robot fitted with flexible detector to find lymph node

20 February 2018• PRESSRELEASE

Modern surgical robots increase the precision of surgery because of their flexible arms. However, not all surgical technology has developed at the same rate. Surgeons still use rigid detectors to find lymph nodes for instance, a procedure often used on cancer patients. Now, researchers of the Leiden University Medical Center (LUMC) and the Antoni van Leeuwenhoek hospital have developed a flexible detector which connects to the flexible arms of surgical robots. Last week the time had arrived for the acid test. For the first time the technology was used on a patient.

During a so-called sentinel lymph node procedure doctors use radioactivity and fluorescence to find lymph nodes to which tumour cells spread first. By removing and examining these nodes the doctor finds out whether the cancer has spread or not. Prior to the operation the doctor injects a radioactive and fluorescent fluid around the tumour, which accumulates in the sentinel lymph node. The most sensitive method to identify this node is by using a gamma probe. A gamma probe is a type of metal stick with a sensor at the end which beeps increasingly faster when it comes close to radioactivity. The fluorescence then serves to confirm the location of the node.

Long straight stick through small opening

Researcher Matthias van Oosterom of the LUMC: “With the arrival of laparoscopic robotic surgery where the instruments are inserted in the patient through tiny holes and the surgeon operates the robot from a console, rigid detection techniques are no longer the best solution. Because the gamma probe is a long straight stick which has to go through a narrow opening, it only has limited moving space in the patient’s body. Also, the operation assistant has to move the probe while the surgeon gives instructions from the console.”

During his master traineeship Van Oosterom developed together with Eurorad an alternative: the DROP-IN gamma probe. He disconnected the sensor from the stick. “As the name ‘drop-in’ implies, the assistant drops our probe in the patient via one of the openings also used for the surgical instruments. Next, the surgeon grabs it with the arm of the surgical robot. That arm has a wrist joint which gives the probe rotational freedom in all directions.”

Greater control

On Thursday 15 February the researchers tested their DROP-IN gamma probe for the first time on a patient during a prostate operation in the Antoni van Leeuwenhoek hospital. “We work closely together with urologist Henk van der Poel, who has a lot of experience with robotic surgery on patients suffering from prostate cancer. Despite thorough preclinical testing of the DROP-IN probe, it was an exciting moment”, according to Pip Meershoek, the LUMC PhD researcher who coordinates the clinical study. After the operation Van der Poel came to the following conclusion: “The DROP-IN gamma probe gives me a better node detection control. The clinical study has to show whether the new gamma probe will also improve the detection of lymph node metastasis."

The DROP-IN gammaprobe in action (English)

The clinical study is partly funded by surgical robot manufacturer Intuitive Surgical Inc. and carried out by the research group of Dr. Fijs van Leeuwen (Radiology department, LUMC) and the Urology department of the NKI-AvL.

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