Commentary: Subxiphoid thymectomy: Sometimes the middle of the road is best

Robert J. Cerfolio, MD, MBA

Central Message.

Innovation of surgical techniques is challenging but valuable. A subxiphoid approach for robotic thymectomy has great promise but will require further studies.

See Article page 368.

We congratulate Hashimoto and Sakamaki¹ on being innovative. Innovation can be challenging in medicine, especially when it comes to surgical techniques. We believe it is the only way to improve. We agree with the authors that performing a thymectomy from the middle provides the best view of all of the pertinent anatomy. This is why a median sternotomy was the optimal choice 15 years ago. In addition, it is why organizations such as ours that has an the XP robot (Intuitive Surgical, Sunnyvale, Calif) (a single-port robotic platform) believes that perhaps the greatest utilization of the XP robot in thoracic surgery will be for midline, subxiphoid thymectomy and probably not for pulmonary resections. However, that robotic system is not yet approved for this indication and thus is not ready for prime time. That leaves us, for now, with the thoughtful consideration of the advantages and disadvantages of this study, which applies a midline robotic thymectomy performed with Xi or Si robot.

We have actually performed 1 of these procedures more than 9 years ago. That patient developed a small incisional hernia postoperatively. He, like many Americans, was overweight (body mass index, 37). The experience halted our further adoption of this technique. And it brings us to some of our concerns and questions for the authors.

It appears that the main advantage of the midline approach is the ability to see both phrenic nerves. However, does this advantage, which is undoubtedly true (you can see more of both phrenic nerves from a camera placed subxiphoid then a camera placed on either side of the chest) have any true clinical significance? We can only relay our own experience with performing more than 336 thymectomies. We prefer the left side of the chest for almost all patients and for those with myasthenia gravis and for midline tumors. We only choose the right side if the mass is large (≥7 cm) and located almost exclusively in the right side of the chest and is in a patient without myasthenia gravis. Our outcomes are good: no known or documented injuries to either phrenic nerve, complete R0 resections of all patients' tumors (except those who have multifocal B-2 thymomas), no conversions, median blood loss of 20 cc (range, 10-70 cc), no transfusions, median operative time of 73 minutes, median length of stay of 1 day (range, 1-3 days), we do not use a chest tube allowing many to go home the day of the operation or the next morning, and no 30- or 90-day mortality. We and most surgeons can see enough of each nerve from a contralateral chest position to safely perform the operation and we do not place a camera in the contralateral chest. This avoids the patient from having any incisions in the opposite chest and we do not use a chest tube to close but rather a sucker to aspirate the air as the lung re-expands at the time of closure. Does the new technique add value to the results listed above that most of us—not just us here at NYU Langone—achieve regularly?

The provided video and operative conduct can be improved in several ways. First, the order and manner in which the ports are placed should be shown. Second, the dissection of the tissue near the phrenic nerves should be carried out closer to the phrenic nerves than is shown, especially on the left side. The authors have left too much tissue near the nerve that can harbor ectopic thymic tissue. Third, we routinely dissect out the tissue under the innominate vein even in patients without myasthenia gravis because some patients who present with thymoma who may not have myasthenia gravis at the time of presentation can develop myasthenia gravis later in life. Thus, they may benefit from a complete radical thymectomy up front. Because this is easy to do and offers no significant morbidity or risk, it is our default operation whenever possible. Fourth, all of the tissue should be removed off the entire pericardium from phrenic nerve to phrenic nerve, including the aortopulmonary tissue area. Fifth, the use of a bipolar in the surgeon's operating hand (in the provided video it is a right-handed surgeon) allows for better and closer nerve dissection than a vessel sealer. In addition, the vessel sealer is more expensive and avoids using 2 instruments instead of 1. We use only 1 instrument per port to reduce cost, variables, and instruments swapping—all of which lowers operative times, reduces cost, and improves value. However, it is true that the port placement for a left-sided thymectomy is tricky and the operation is not technically simple.

The disadvantages of the author's technique are:

• •It requires incisions in both sides of the chest, which may lead to more pain;
• •It may lead to a midline hernia in obese patients; and
• •It has a learning curve and adds the chance of a cardiac injury upon entry; although, to be fair, so does a left-sided approach.

The advantages, however, seem to be many:

• •One sees more of both phrenic nerves and this may lower the chance of phrenic nerve injury;
• •It may lower the chance of cardiac injury if the subxiphoid port is placed after the left side of the chest has been entered, a camera is placed, and carbon dioxide insufflated to push the heart away as the subxiphiod trocar is placed under direct vision;
• •It may cause less pain as the result of using an abdominal port that avoids the intercostal nerves;
• •It may be easier to teach than a unilateral chest approach that requires a few tricks to view the phrenic nerve in the opposite side of the chest;
• •It may be easier to bag via a midline approach and may allow larger tumors to be removed, as one could easily use a subcostal incision as well for extraction; and
• •It allows one to always see under the subinnominate vein zone on the left side and thus fully remove the ectopic thymic tissue that is commonly found in this area (this cannot be done from the right chest).

We congratulate Hashimoto and Sakamaki¹ on their desire to innovate and to improve patient care and outcomes. We love their spirits and the article's message is clear. In patients like those in the United States or other parts of the world where people are more likely to have a higher body mass index, the disadvantages of this technique have to be carefully considered and, pardon the pun, weighed.

Although nothing is proven in this study except feasibility it is important to note that leadership requires vision and often a P value is not available. The authors have inspired us—and we hope others—to retry the subxiphoid approach and assess its merits in appropriately selected patients. Vision is critical for innovation. Perhaps their suggested view from the middle of the road provides the optimal pathway for a new surgical technique.