Robot-assisted kidney transplant surgery

The New York Times journalist Tiff Fehr recounted a heart-warming story about how she donated her kidney to a fellow journalist Michelle Minkoff. It was a very generous and selfless act by Ms Fehr, and thankfully the whole operation went off without a hitch leading to a happy ending.

Along with the heart-warming story, what caught my attention. was that she mentioned that the kidney transplant surgery was robot-assisted. I have previously written about the increasing use of robots for certain surgical procedures. The article did not specify the type of robot, but a little sleuthing produced the most likely candidate: da Vinci by Intuitive Surgical.

The da Vinci surgical robot was approved by the FDA about 15 years ago (QH). It is "designed to facilitate complex surgery using a minimally invasive approach, and is controlled by a surgeon from a console. The system is commonly used for prostatectomies, and increasingly for cardiac valve repair and gynecologic surgical procedures" (i.e. hysterectomies). However, Da Vinci is more machine-aided surgery than robot surgery with a human operator controlling the action of 4 robotic arms. The value-added includes providing "surgeons with superior visualization, enhanced dexterity, greater precision and ergonomic comfort," but the autonomy is limited with a surgeon controlling the vast majority of movements.

Recently the da Vinci system has been applied to kidney transplant surgery (Robot-Assisted Kidney Transplant or RAKT) with some good results. A kidney transplant operation is not that complicated all things considered. It involves making an incision in the abdomen, inserting the donor kidney below the recipient's malfunctioning kidneys, fixing it in place, attaching the renal artery and vein to the appropriate blood vessels, and finally ligating the donor ureter to the recipient bladder (Figure 1). The hard steps are stitching together all the plumbing, i.e. blood vessels and ureter (Healthline):

"Once you’re asleep, your doctor makes an incision, or cut, in your abdomen and places the donor kidney inside. Your doctor then connects the arteries and veins from the kidney to your arteries and veins. This will cause blood to start flowing through the new kidney. The doctor will also attach the new kidney’s ureter to your bladder so that you’ll be able to urinate normally. The ureter is the tube that connects your kidney to your bladder."

The renal artery normally branches out from the aorta, and the the renal vein and the However it is done a bit below to keep the kidneys in place to limit the amount of trauma and lower down connecting to the illiac artery and vein instead of the aorta artery and inferior vena cava.

The da Vinci surgical robot (which is controlled by the surgeon) possesses certain advantages over a human surgeon operating manually. These include improved dexterity since the robotic "hands" (forceps) can be turned and twisted in any direction and they are smaller than human hands. In addition, there are 4 arms (not just 2), and the system possesses improved visibility by exploiting multiple camera perspectives instead of just two eyes. The reduced size, improved dexterity, and enhanced vision allows for a smaller abdominal incision.

In the video below (Video 1), you can see da Vinci in action during a kidney transplant operation. Three of the main steps in the procedure are performed by the surgeon-controlled robotic arms, including connecting the donated kidney renal artery, renal vein, and ureter to the appropriate structures in the recipient. The dexterity displayed during the suturing is very impressive.

Video 1. Robot-Assisted Kidney Transplant surgery (RAKT) performed by the da Vinci robot at the University of Illinois.

Remember that da Vinci's arms are still controlled by the surgeon (sort of but not quite like Doctor Octopus in Spider Man). Suturing is very much like sewing, which has been completely automated by sewing machines. Thus it is not surprising, as I have described in a previous post, that engineers have constructed a robot that could perform suturing in a semi-autonomous fashion without the direct control of a surgeon. The researchers tested their robot called Smart Tissue Autonomous Robot (STAR) on a task of intestinal anastomosis (i.e. a section of the intestines is surgically removed and the two remaining ends are sewn together) in the pig. The researchers found that their robot was superior in many respects to a human surgeon performing the same operation:

"Shademan et al. designed a “Smart Tissue Autonomous Robot,” or STAR, which consists of tools for suturing as well as fluorescent and 3D imaging, force sensing, and submillimeter positioning. With all of these components, the authors were able to use STAR for soft tissue surgery—a difficult task for a robot given tissue deformity and mobility. Surgeons tested STAR against manual surgery, laparoscopy, and robot-assisted surgery for porcine intestinal anastomosis, and found that the supervised autonomous surgery offered by the STAR system was superior."

In the near future, I expect the da Vinci system to be deployed more frequently for kidney transplant and other "routine" surgeries. In the not-so-distant future, one can expect that semi-autonomous robots such as STAR will be able to carry out key steps of the operation essentially on their own (under the supervision of surgeons). In the more distant future, robots will be able to complete most operations from start to finish on their own with high precision and safety.

Figure 1. Diagram of a kidney transplant which shows that the transplanted kidney is inserted below the two native (damaged) kidneys. The key connections must be made from the transplanted kidney to the recipient circulatory system and bladder. The kidney takes blood in through the renal artery, and then after certain waste components are removed, the blood exits via the renal vein. The waste products are sent down the ureter to the bladder where they are expelled in the urine.