Robotic Thymectomy by Kemp H. Kernstine M.D., Ph.D. (with interview)
[editor’s note: In this interview, and his accompanying article, Dr. Kernstine commented on the use of the da Vinci surgical system in these sensitive myasthenia gravis cases.]
“Myasthenia gravis is an uncommon disease, which strikes young females in their 20s to 30s. In 10 to 15% of all cases, the patient will have a thymoma, which is a cancer of the thymus. In the past, the method of treatment has been a median sternotomy, although you can imagine that a young 20-year-old female being told they need to have this extensive surgery doesn’t sit very well,” said Dr. Kemp Kernstine, MD, PhD, director of the department of thoracic surgery and lung cancer and the thoracic oncology program at the City of Hope Medical Center in California.
The open surgery method requires extensive dissection from the diaphragm, all the way up to the thyroid, into the left and the right chest; in short, the surgeon has to completely remove all the mediastinal tissue in these patients.
As an alternative to the traditional open method for myasthenia gravis cases, Kernstine makes a selective use of the da Vinci surgical system.
“We use the robot selectively. If we feel this is going to be a curative, not a palliative procedure for this patient, we will typically choose robotics,” Kernstine said.
Myasthenia gravis can be a terribly debilitating disease in these patients, he added. “They have blurry vision, droopy eyelids, difficulty talking and swallowing, as well as muscle and respiratory weakness. They can wind up on a ventilator,” Kernstine said.
While Kernstine does not intentionally use robotic surgery to remove a thymus from a myasthenia gravis patient, the doctor did note his success so far with the operation.
“Where’s the cost effectiveness of adding robotics? I think it’s going to be in a wider, more complete resection, with less likelihood for local recurrence,” he said.
City of Hope’s large medical robotics program uses three of the original da Vinci models, he said. “We haven’t got the ‘S’ model yet, although I’ve gone up to Sunnyvale to examine it, and it has some features that may be more useful to the non-prostate, non-heart surgeon. The robotic arm chassis is a little lighter. The older system has these arms that stick out away from the patient’s abdomen or chest, and with the ‘S’-model, these arms are collapsible so they don’t hit against each other when they’re moving at extremes of robot,” Kernstine added.
Robotic Thymectomy
Kemp H. Kernstine M.D., Ph.D.
City of Hope Medical Center and Beckman Research Institute
Los Angeles, California
The thymus is vestigel organ that exists in the upper anterior mediastinum draped over the great vessels and superior aspect of the heart from the thyroid gland to the mid-heart level. Its function is largely in immunological development largely prior to birth. As its functional importance is lessened, it begins to atrophy, roughly at 6 to 9 months of age. By 20 years of age, the thymus is fairly small and in the majority of patients there is minimal tissue by 40 years of age. Several disease processes can occur within thymic tissue; including cancer, hyperplasia, the presence of foreign active tissues such as the thyroid, parathyroid and germ cell tissue, remnants stem or multipotent cells that may develop into defined tissues such as eye, bone, cartilage, hair etc.. The most common reason for removal of the thymus is to evaluate and diagnose masses or nodules within the thymic gland suspicious for cancer. Historically the thymus removal or thymectomy was performed in the same fashion as heart surgery, by median sternotomy or by thoracotomy, incisions in the midportion or on either side of the chest. As a result, patients would remain hospitalized for 5 to 10 days and would not return to work for 6 weeks, not being able to lift any more than 10 pounds for that period of time.
The presence of myasthenia gravis is another common reason for thymectomy. Since the early 1900s the correlation between thymic pathology and myasthenia symptoms, weakness with repetitive use, has been recognized. Basic science discoveries have found that the thymus is an important organ in the initiation and potentially perpetuation of the disease. The resultant development of antibodies directed against the post synaptic endplate acetylcholine receptors results in gradual and persistent destruction so that the clinical presentation of weakness continues to worsen until the patient is unable to breathe or perform any of the simple routine daily tasks. In any patient, this is a devastation, but the typical patient is female in their 20s to 40s, the prime of their lives. Numerous medications have been developed to control, but not arrest, the symptoms. Approximately 10% of patients will spontaneously go into remission regardless of the management.
The potential of surgical removal arresting the disease was theorized in the early 1900s, but it was not until the 1940s that the first series of thymectomies was reported. The video-assisted and transcervical techniques were later developed and in relatively small retrospective series, appear to provide a similar remission rate as the open technique, 30 to 60% by 5 to 8 years. Though, they do not appear to have the same rate of remission as the more surgically-aggressive extended thymectomy, and complete removal of the thymus and all peri-thymic tissue from diaphragm up to the thyroid gland and into both chests through a median sternotomy and additional neck incision, over 80% at 10 years. Unfortunately, these percentages are from retrospective reviews with nonstandard definitions of remission. As a result, many neurologists and their patients are reluctant to subject themselves to a major operation of which the majority are performed by a large midline sternal incisions and are associated with a relatively long recovery. Concerns have been raised about the less invasive approaches, the transcervical thymectomy and the video-assisted technique, as they may not remove all of the thymus or the remnant thymic tissue often found in the anterior mediastinal fat, potentially reducing the likelihood for remission.
Computer-assisted surgical systems or robotic surgery was approved by the Food and Drug Administration in the mid to lower 1990s. The first United States robotic chest procedures were performed in 2002. One of the first was thymectomy. Our own thymectomy series started in the Fall of 2002. Our earliest findings have found reduced pain with smaller incisions, earlier return to preoperative function, reduced cost of care and apparent reduced likelihood for postoperative myasthenic crisis. We have yet to demonstrate that the greater dexterity, visibility and likely ability to more precisely remove all thymic tissue will result in an improved remission rate. Perhaps, with this approach, it will be a potential therapy for patients earlier in the course of their disease, potentially increasing the rate of remission.
“Myasthenia gravis is an uncommon disease, which strikes young females in their 20s to 30s. In 10 to 15% of all cases, the patient will have a thymoma, which is a cancer of the thymus. In the past, the method of treatment has been a median sternotomy, although you can imagine that a young 20-year-old female being told they need to have this extensive surgery doesn’t sit very well,” said Dr. Kemp Kernstine, MD, PhD, director of the department of thoracic surgery and lung cancer and the thoracic oncology program at the City of Hope Medical Center in California.
The open surgery method requires extensive dissection from the diaphragm, all the way up to the thyroid, into the left and the right chest; in short, the surgeon has to completely remove all the mediastinal tissue in these patients.
As an alternative to the traditional open method for myasthenia gravis cases, Kernstine makes a selective use of the da Vinci surgical system.
“We use the robot selectively. If we feel this is going to be a curative, not a palliative procedure for this patient, we will typically choose robotics,” Kernstine said.
Myasthenia gravis can be a terribly debilitating disease in these patients, he added. “They have blurry vision, droopy eyelids, difficulty talking and swallowing, as well as muscle and respiratory weakness. They can wind up on a ventilator,” Kernstine said.
While Kernstine does not intentionally use robotic surgery to remove a thymus from a myasthenia gravis patient, the doctor did note his success so far with the operation.
“Where’s the cost effectiveness of adding robotics? I think it’s going to be in a wider, more complete resection, with less likelihood for local recurrence,” he said.
City of Hope’s large medical robotics program uses three of the original da Vinci models, he said. “We haven’t got the ‘S’ model yet, although I’ve gone up to Sunnyvale to examine it, and it has some features that may be more useful to the non-prostate, non-heart surgeon. The robotic arm chassis is a little lighter. The older system has these arms that stick out away from the patient’s abdomen or chest, and with the ‘S’-model, these arms are collapsible so they don’t hit against each other when they’re moving at extremes of robot,” Kernstine added.
Robotic Thymectomy
Kemp H. Kernstine M.D., Ph.D.
City of Hope Medical Center and Beckman Research Institute
Los Angeles, California
The thymus is vestigel organ that exists in the upper anterior mediastinum draped over the great vessels and superior aspect of the heart from the thyroid gland to the mid-heart level. Its function is largely in immunological development largely prior to birth. As its functional importance is lessened, it begins to atrophy, roughly at 6 to 9 months of age. By 20 years of age, the thymus is fairly small and in the majority of patients there is minimal tissue by 40 years of age. Several disease processes can occur within thymic tissue; including cancer, hyperplasia, the presence of foreign active tissues such as the thyroid, parathyroid and germ cell tissue, remnants stem or multipotent cells that may develop into defined tissues such as eye, bone, cartilage, hair etc.. The most common reason for removal of the thymus is to evaluate and diagnose masses or nodules within the thymic gland suspicious for cancer. Historically the thymus removal or thymectomy was performed in the same fashion as heart surgery, by median sternotomy or by thoracotomy, incisions in the midportion or on either side of the chest. As a result, patients would remain hospitalized for 5 to 10 days and would not return to work for 6 weeks, not being able to lift any more than 10 pounds for that period of time.
The presence of myasthenia gravis is another common reason for thymectomy. Since the early 1900s the correlation between thymic pathology and myasthenia symptoms, weakness with repetitive use, has been recognized. Basic science discoveries have found that the thymus is an important organ in the initiation and potentially perpetuation of the disease. The resultant development of antibodies directed against the post synaptic endplate acetylcholine receptors results in gradual and persistent destruction so that the clinical presentation of weakness continues to worsen until the patient is unable to breathe or perform any of the simple routine daily tasks. In any patient, this is a devastation, but the typical patient is female in their 20s to 40s, the prime of their lives. Numerous medications have been developed to control, but not arrest, the symptoms. Approximately 10% of patients will spontaneously go into remission regardless of the management.
The potential of surgical removal arresting the disease was theorized in the early 1900s, but it was not until the 1940s that the first series of thymectomies was reported. The video-assisted and transcervical techniques were later developed and in relatively small retrospective series, appear to provide a similar remission rate as the open technique, 30 to 60% by 5 to 8 years. Though, they do not appear to have the same rate of remission as the more surgically-aggressive extended thymectomy, and complete removal of the thymus and all peri-thymic tissue from diaphragm up to the thyroid gland and into both chests through a median sternotomy and additional neck incision, over 80% at 10 years. Unfortunately, these percentages are from retrospective reviews with nonstandard definitions of remission. As a result, many neurologists and their patients are reluctant to subject themselves to a major operation of which the majority are performed by a large midline sternal incisions and are associated with a relatively long recovery. Concerns have been raised about the less invasive approaches, the transcervical thymectomy and the video-assisted technique, as they may not remove all of the thymus or the remnant thymic tissue often found in the anterior mediastinal fat, potentially reducing the likelihood for remission.
Computer-assisted surgical systems or robotic surgery was approved by the Food and Drug Administration in the mid to lower 1990s. The first United States robotic chest procedures were performed in 2002. One of the first was thymectomy. Our own thymectomy series started in the Fall of 2002. Our earliest findings have found reduced pain with smaller incisions, earlier return to preoperative function, reduced cost of care and apparent reduced likelihood for postoperative myasthenic crisis. We have yet to demonstrate that the greater dexterity, visibility and likely ability to more precisely remove all thymic tissue will result in an improved remission rate. Perhaps, with this approach, it will be a potential therapy for patients earlier in the course of their disease, potentially increasing the rate of remission.
posted by John J. Otrompke | 12:24 PM
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