"The future of surgery is not about blood and guts; the future of surgery is about bits and bytes.”
/Dr. Richard Satava/

Sunday, March 29, 2009

Robotic surgery in space I.

Human space flights have always been cost demanding due to the increased safety measures required to protect the astronauts. Throughout the missions on board of Skylab, the Russian MIR or the International Space Station (ISS), numerous health risks have been identified. In the case of long duration space missions beyond Earth orbit–such as the scheduled Mars mission
or the permanent Moon base–there is an increased health hazard. Several medical problems may arise involving the bone system, the gall bladder, the pancreas, the appendix, the urinal system or the blood circulation. No matter how thoroughly the astronauts are monitored beforehand, the chance of sudden illness or injury cannot be excluded. Patients have to be treated (including surgical procedures) not to endanger the success of the whole mission.
Along this idea NASA and DARPA have sponsored various research projects to develop a light-weight and universal robotic tool for space missions.
The BioRobotics Lab at University of Washington have developed a portable surgical robot that can be a compromised solution to install on spacecrafts with its 22 kg overall mass. The robot–called Raven–has two articulated arms, each holding a stainless steel shaft for different surgical tools. It can easily be assembled even by non-engineers, and its communication links have been designed for long distance remote-control. Besides the possibility of haptic feedback, additional sensors are mounted on the robot, to provide more information to the surgeon and to avoid any critical failure due to communication delay. Throughout the entire development, compactness was handled as priority, the creators optimized the robot’s dimensions and motion by computer, minimizing the space it occupies without compromising on manipulation capabilities.
Realizing the importance of a light, but stiff structure, SRI International in Menlo Park, California started to develop the M7 in 1998, another portable and deployable light-weight surgical robot (Figure 3.). The system weights only 15 kg, but able to exert significant forces compared to its size. The system consists of two 7DOF arms, and is equipped with motion scaling (1:10), tremor filtering and haptic feedback. The effectors used by the robot can be changed very rapidly, and even laser tissue welding tool can be fixed on it. The controller has been designed to operate under extremely different atmospheric conditions, and for this purpose the robot only contains solid-state memory drives. The software of the M7 has been updated lately to better suit the requirements of teleoperation and communication via Ethernet cable.
The German Aerospace Center (DLR) has already built several generations of light-weight robotic arms for ground and space application. Their 7DOF surgical robot is called KineMedic, and as one arm is only 10 kg and capably of handling 30 N payload with high accuracy, it is considered for space use as well. Its industrial version is equipped with a dexterous 4-finger artificial hand, and has already won several awards. The most recent development is called the MIRO that is capable of performing da Vinci-style MIS operations.
Engineers at the University of Nebraska together with the physicians of the local Medical Center had detached from the classic manipulator design, and developed a special mobile in-vivo wheeled robot for biopsy. Equipped with a camera, the coin-sized robot can enter the abdominal cavity through one small incision and move teleoperated around the organs. The robot is able to traverse the abdominal organs without causing any damage, therefore reduces the patient trauma. The lead-screw linkage system actuating the graspers enables relatively large force production. The revolutionary robot project evolved into a new direction, dealing with self-assembling micro-manipulators with magnetic anchoring.

Monday, March 23, 2009

2nd Hungarian NOTES Congress

The 2nd Hungarian NOTES Congress was held on the last Saturday of February, at the 1st Dept. Of Surgery of the Semmelweis University in Budapest. (A Hungarian report can be found here.) The organizers, the Hungarian Invasive Flexible Endoscopy Association has been promoting the Natural Orifice Translumenal Endoscopic Surgery (NOTES) for a couple of years, and managed to bring together around 200 professionals and observers for the congress. The first half of the program consisted of 15 min lectures, presenting the state of the art of NOTES techniques and devices. Then, Hungarian clinics presented their results in NOTES: the Dept. of Surgical Research and Techniques at Pécs University performed the first animal trial in October 2008. Also, animal trails were performed at the Semmelweis University in December, experimenting with newly developed flexible endoscopes and magnetic camera anchoring system.
I was given a chance to present the most recent advancements in robotic NOTES, providing a snapshot to the most advanced automated tools and devices. The organizers also invited skeptic professionals, presenting their doubts and fears in connection with the new operational techniques.
In the coffee breaks, invited manufacturers presented their endoscopic equipment. The Immersion Medical brought two laparoscopic trainers, and Balazs Lengyel demoed with his training box. In the afternoon, a special hands-on training session was organized, including transgastric abdominal explorative flexible endoscopy, invasive endoscopy and submucosus dissection on biosynthetic model. Altogether, it was a great event bringing together the potent people of the field, and giving hope to see significant development on the NOTES area even in Hungary.

Friday, March 6, 2009

Da Vinci procedures III

No doubt about it, the da Vinci became a success story. According to Intuitive’s site, there have been 1,111 unit shipments (825 in the US, 194 in Europe and 92 in the rest of the world), as of December 2008. This large number of deployed robots also means an exponential rise in the amount of procedures performed. In total, it’s above 300,000 by now.
Despite the large number, the reported device failure and complication rate is still relatively low.
Patel (2007) reports 4.7% complication ratio (based on 900 cases). Bodnera (2005) observed 2% conversion to laparoscopy and 3% conversion to open surgery (128 cases). Olthof (2007) reports 2.27% conversion (400 cases). For Robot-Assisted Laparoscopic Radical Prostatectomy (RLRP) the numbers are even lower: Borden (2007) found 2.6% technical problems(350 RLRP), while Zorn 2007 observed 0.4% conversion to laparoscopy and 0.5% conversion to open surgery (850 RLRP). These are well under the average ratio in the case of classic laparoscopy. In addition, Koliakos (2008) reports 1% software failure and 1 case of broken EndoWrist from O.L.V. Clinic, Belgium (520 cases).
According to Borden (2007) the main mechanical issues with the da Vinci are:
  • Mechanic failure of wrist
  • Mechanic failure of arm
  • Power supply
  • Loss of 3D display
  • Camera error
  • Breakage of master device
  • Failure of slave device
  • Software errors
There has only been one serious case in 2002, in St. Joseph's Hospital Tampa, FL. During a robotic nephrectomy, two renal arteries have been cut accidentally, and the bleeding stayed unnoticed until the end of the procedure, when it was too late to save the patient. No technical failure of the robot was found.
In the past years, the da Vinci had received FDA approval for a dozen operations, but the system has been used with more than 100 procedures, out of which a couple showed significant clinical advantage over the classic methods.
Yet, prostatectomy stays the killer application of the da Vinci, and app. 70% of all radical prostate procedures were performed with the da Vinci robot last year in the US.
A new field of application for the da Vinci is the R-NOTES, the Robotic Natural Orifice Translumenal Endoscopic Surgery. There have been reported thoracic, transrectal and transumbilical procedures, mostly on animals. More interesting that da Vinci was demonstrated to be an effective help even in origami.

Image credit: Box et al (2008)