Medical Robotics Announces an Early Look at the Robotic Thyroidectomy Data of Prof. Woong Youn Chung

Da Vinci Thyroid Studies Suggest Advantages,  Disadvantages Compared to Endoscopic and Open Surgery

By John Otrompke

   Korean surgeons have now gained enough experience using the da Vinci surgical robot to perform operations for thyroid cancer that researchers are able to describe preliminary findings comparing robotic to endoscopic to conventional open procedures.

   To a significant extent, more lymph nodes are retrieved in robotic thyroidectomies than in conventional endoscopic procedures, research indicates. If compared to open surgery, however, the same number of lymph nodes were retrieved, according to a smaller, preliminary comparative study.

   The rate of transient hypocalcemia was significantly greater in robotic surgery than in endoscopic procedures, however, as was the rate of permanent recurrent laryngeal nerve palsy.

   Post-operative mean thyroglobulin level, used as a surrogate marker for remaining or recurring cancer, was lower in robotic procedures than in open procedures. Hyperesthesia or paresthesia was also diminished in patients who had robotic procedures in comparison with conventional open thyroidectomy, according to research which has yet to be published.

   “There are technically some limitations of robotic surgery compared to conventional open surgery for advanced thyroid surgery, such as trachea resection and reconstruction, as well as mediastinal lymph node dissection,” said Dr. Woong Youn Chung, surgeon at Yonsei University College of Medicine, in Seoul.

   “Compared to endoscopic surgery, however, we can applied robot surgery to more advanced thyroid cancer,” said Chung, who has been performing robotic surgeries since October of 2007.

   Robotic procedures may also offer the advantage of diminished scarring of the neck, he added.

   Chung had performed the robotic surgery in 200 consecutive patients in July 2008, and a paper describing the results, titled “Robot-Assisted Endoscopic Thyroidectomy for Thyroid Malignancies Using a Gasless Transaxillary Approach,” was published in 2009 in the Journal of the American College of Surgeons.

   Now, Chung is updating his data and comparing those patients who had robotic thyroidectomies with those who had endoscopic procedures, in a forthcoming article in the Annals of Surgery. Although mean follow-up time is relatively short at 9.5 months, by March of 2011, Chung and colleagues had performed more than 2,000 such cases, and C hung himself had performed about 1,400 of them. As of last year, a total of about 4,100 robotic thyroidectomies had been performed in Korea, Chung added.

   In a smaller group of 115 patients, Chung and colleague also have compared robotic thyroidectomy with open thyroidectomy, in research yet to be published.

An Interview with Dr. Woong Youn Chung

professor in the department of surgery and chief of the endocrine surgery division at Yonsei University College of Medicine, in Seoul, and past director of the Yonsei Robot and Minimally Invasive Surgery Center.



Medical Robotics: Is it just the learning curve that accounts for these differences?

 Chung: From a Korean multicenter comparative study of differences in the learning curve between endoscopic and robotic surgery, the time requirement for overcoming the learning curve was shorter in robotic group (it was 10 to 15 cases less in the robotic group). This suggests that robotic surgery is easier to learn, and also that a well-organized training program is very important.

MR: Does it take less time now for the preparation or set up of a robotic operation, or for the operation itself?

Chung: In the beginning period, the time requirement for flab dissection was about 50 minutes, docking time was more than 20 minutes, and console time more than 80 minutes. Currently, however, the time for flab dissection is about 30 minutes, docking time less than five minutes, and console time is about 50 minutes. Briefly speaking, the total operation time for a less-than-total thyroidectomy with central lymph node dissection is less than two hours, and for total thyroidectomy with central lymph node dissection, less than two-and-a-half hours.

MR: You said there were no recurrences in the study comparing robotic to endoscopic procedures?

Chung: Papillary thyroid cancer has a mild biological behavior and a favorable prognosis. Papillary thyroid carcinoma is the most common type of thyroid malignancy. It accounts for more than 90% of all thyroid cancers. Although the prognosis of thyroid cancer is excellent (on the basis of World Health Organization data, the 10-year survival rate is more than 90%) , there is a relatively limited indication for robotic thyroidectomy which means we exclude the highly advanced cancer patient as a candidate.

MR: Did physicians choose which patients had robotic surgery, and how?

Chung: I always explain three types of thyroid surgery (open, endoscopic and robotic surgeries) to patients. Robotic surgery is the most expensive procedure in Korea because it can not be covered by national health insurance. Patients choose.

MR: Could you tell us about your gasless approach to thyroid surgery? What is the gas used for?

Chung: We have done only the gasless trans-axillary approach. The bilateral axillo-breast approach requires the use of CO2 gas to maintaining a working space. The gasless trans-axillary approach doesn’t require the gas, because the working space can be maintained during the operation by my own Chung’s retractor.

Comparing Open with Robotic Surgery

              

   In a smaller study comparing robotic thyroidectomy with open procedures, levels of thyroglobulin (used as a surrogate marker for remnant tissue or recurring cancer) were smaller in the robotic group 0.36 nanograms per milliliter compared to 0.83, but the figure was not statistically significant, according to Chung.
   On the other hand, both procedures retrieved the same number of lymph nodes, he said.

   “If compared to open surgery, the operation cost is higher, and operation time is longer, in the robotic group. However, robotic surgery could provide more benefits to both patients and surgeons in terms of cosmesis, swallowing comfort, pain sensation and surgeon’s ergonomics,” according to Chung.

   The study, which is a prospective study in-progress, is destined for the Journal of Surgical Endoscopy, looks at 58 patients treated with open conventional thyroiedectomy, compared to 57 treated robotically.

   Preliminary results showed that although the number of lymph nodes retrieved was the same in both groups, rates of some injuries, such as trachea injury, were higher in the robotic group than in those treated with open surgery (1.8% compared to 0%).

   On the other hand, rates of some adverse events, such as hematoma, were higher in those treated with open surgery. Use of the robot was also associated with diminished hyperesthesia or paresthesia, a strange sensation of the skin in the anterior neck, according to Chung.

Comparing Endoscopic to Robotic Thyroid Surgery

   In a study which has been accepted for publication in the Annals of Surgery, Chung and colleagues compared 570 patients by conventional endoscopic thyroidectomy with 580 patients with the same condition treated with the da Vinci surgical system. The patients had papillary thyroid microcarcinoma (in which the tumor is smaller than a centimeter) without definite extrathyroidal tumor invasion ; those treated endoscopically were treated between November of 2001 and July of 2009, while those treated robotically were enrolled between October of 2007 and July of 2009.

   The number of retrieved central nodes was significantly greater in the robotic surgery group (4.3) compared to the endoscopic group (3.6).

   However, the rate of transient hypocalcemia was significantly more frequent in the robotic surgery group (37.8% versus 19.7%), as was the rate of permanent recurrent laryngeal nerve palsy (four patients in the robotic surgery group, or 0.7% of the total, compared to only one in the endoscopic group.
Postoperative hospital stays were not significantly different in either group, and there was no recurrence of the disease in either group, Chung said.

An Early Look at the Robotic Thyroidectomy Data of Prof. Woong Youn Chung

Preliminary Data from Two Journal Articles

An Interview with Dr. Woong Youn Chung

professor in the department of surgery and chief of the endocrine surgery division at Yonsei University College of Medicine, in Seoul, and past director of the Yonsei Robot and Minimally Invasive Surgery Center.


Medical Robotics: Is it just the learning curve that accounts for these differences?
Chung: From a Korean multicenter comparative study of differences in the learning curve between endoscopic and robotic surgery, the time requirement for overcoming the learning curve was shorter in robotic group (it was 10 to 15 cases less in the robotic group). This suggests that robotic surgery is easier to learn, and also that a well-organized training program is very important.
MR: Does it take less time now for the preparation or set up of a robotic operation, or for the operation itself?
Chung: In the beginning period, the time requirement for flab dissection was about 50 minutes, docking time was more than 20 minutes, and console time more than 80 minutes. Currently, however, the time for flab dissection is about 30 minutes, docking time less than five minutes, and console time is about 50 minutes. Briefly speaking, the total operation time for a less-than-total thyroidectomy with central lymph node dissection is less than two hours, and for total thyroidectomy with central lymph node dissection, less than two-and-a-half hours.
MR: You said there were no recurrences in the study comparing robotic to endoscopic procedures?
Chung: Papillary thyroid cancer has a mild biological behavior and a favorable prognosis. Papillary thyroid carcinoma is the most common type of thyroid malignancy. It accounts for more than 90% of all thyroid cancers.
Although the prognosis of thyroid cancer is excellent (on the basis of World Health Organization data, the 10-year survival rate is more than 90%) , there is a relatively limited indication for robotic thyroidectomy which means we exclude the highly advanced cancer patient as a candidate.
MR: Did physicians choose which patients had robotic surgery, and how?
Chung: I always explain three types of thyroid surgery (open, endoscopic and robotic surgeries) to patients. Robotic surgery is the most expensive procedure in Korea because it can not be covered by national health insurance. Patients choose.
MR: Could you tell us about your gasless approach to thyroid surgery? What is the gas used for?
Chung: We have done only the gasless trans-axillary approach. The bilateral axillo-breast approach requires the use of CO2 gas to maintaining a working space. The gasless trans-axillary approach doesn’t require the gas, because the working space can be maintained during the operation by my own Chung’s retractor.

All contents copyright 2011 John J. Otrompke, JD

New Products from Tekscan May Boost Robotic Innovation in the Medical Field

Sensors May Go Into Experimental "Laprobot" at UCLA

by John Otrompke

                A new engineering strategy on the part of a major manufacturer of robotic components may already be spurring changes in the reviving economy.

                New sensor kits and connection options made available at the of last year by Tekscan may be incorporated into a new surgical robot being worked on at the University of California- Los Angeles.

            “We were responding to demands from the market for more connection options,” said Elizabeth Hood, marketing specialist at Boston-based Tekscan. “We now offer alternate connection methods,” Hood explained. “Whereas our traditional connection method involves terminating our sensors with pins, we now also offer a single-sided connection method which lets customers use zero insertion force or low insertion force connections,” she said.

                The new products are proving popular. “We have seen a lot of interest among the robotic community in our standard sensors and in the starter kits,” Hood said. Tekscan sensors are already used in medical applications such as mammogram models, dental applications, and infusion pumps.

            The new robot under development would use the Tekscan sensors as part of a pneumatic balloon-based tacticity system, according to Dr. Martin Culjat, PhD, adjunct professor and research director at the Center for Advanced Surgical and Interventional Technology at UCLA.

                The Center, which is a customer of Tekscan and was founded in 2004, has already designed a haptic system for use in lower-limb prosthetics, using the sensors, Culjat said.  “We’ve been able to incorporate a sensor on the prosthetic feet of  amputees, which transmits the force to the limbs,” he explained.

“There aren’t many sensors that are very thin, and light-weight with appropriate pressure ranges  for tactile sensitivity. There are proposed solutions, but this is a really challenging problem,” he explained.

The haptic system under development at UCLA may be applicable to any surgical robot, although the researchers there are working specifically with the da Vinci. Furthermore, the Center is also building its own robot, called the Laprobot, Culjat added.

“We literally dice the sensors  up ourselves, and carefully place them on to the big grasper. Our actuator has six elements for a much better response to the human sensory system,” according to Culjat.

New One-Stop Flexiforce Kits from Tekscan Now Available On-line for Only $99!

“Our new starter kits are actually a new addition to our product line in response to customer demand.  We just added them at the end of 2010,” said Tekscan’s Elizabeth Hood.   

“Prior to this, we never sold the circuit components directly, so customers had to source the components themselves.  The kit contains all the components necessary to build any of our three recommended circuits, along with a detailed user manual and 2 free sample A201 sensors,” she added.

Prominent Engineer in the Field of Medical Robotics Joins Editorial Advisory Board

Professor Hsiao-Wei Tang, PhD, Joins the Board

   Medical Robotics Magazine welcomes the addition of Professor Hsiao-Wei Tang, PhD, to the editorial advisory board. Professor Tang is Director of the International Center of Excellence in Medical Robot, a part of Institut de Recherche contre les Cancers de l’Appareil Digestif/European Institute of TeleSurgery (IRCAD-EITS).



   Dr. Tang, also Adjunct Assistant Professor, National Cheng Kung University in Tainan City, Taiwan, previously designed the experimental VESALIUS Robot.


   “The new Center of Excellence is not intended to be limited to Taiwan only,” Tang said. “My idea is to make the Center of Excellence the meeting place of new surgical techniques and new engineering solutions.”