Clinical and Health Affairs
Robotic Surgery for Head and Neck Cancer
By Eric J. Moore, M.D., and Daniel L. Price, M.D.
■ During the last decade, robotic surgery has evolved from a novelty to the preferred surgical method for urologic, gynecologic, thoracic, cardiothoracic, and gastrointestinal procedures. The use of robotics in head and neck surgery grew out of the success of other transoral surgical modalities used to remove head and neck tumors. This article reviews the evolution of head and neck surgery, the current capabilities of surgical robots, and anticipated future applications of this technology.
Treating patients with head and neck cancers involves controlling the tumor and preserving the form and function of the anatomy. With the recognition that traditional “open” surgical techniques sacrificed function in exchange for exposure, head and neck surgery evolved in several directions. Microvascular surgery attempted to preserve function by reconstructing surgical defects with healthy transplanted tissue. Other protocols attempted to avoid radical removal of tissue by replacing surgical resection with chemoradiation. As these methods were being developed, some surgeons began using minimally invasive techniques that took advantage of the body’s natural orifices and required only small-port incisions. They used endoscopes, coupled with high-definition cameras or microscopes, to visualize the surgical field and specially designed endoscopic instruments for retraction, cutting, and hemostasis. They also used lasers to cut tissue and seal vessels without having to lay hands on the tissue. The motivation behind the search for less-invasive ways to surgically treat head and neck cancers has been to minimize trauma and scarring and to facilitate recovery and achieve more rapid return to activity.
Endoscopic laser surgery and transoral laser microsurgery were developed by Jako and Strong in the early 1970s as a way to ablate and remove malignant tissue in the larynx without external incisions.1 These techniques became proven methods for removing tumors of the larynx and aerodigestive tract that could be accessed through laryngoscopes and transoral retractors.2,3 Although these surgeries minimized tissue trauma and facilitated recovery, they also introduced unique challenges. One limitation of transoral endoscopic surgery was the fact that the microscope lens and means of laser delivery hindered the surgeon’s ability to see and manipulate tumors “around a corner.” In addition, endoscopic laser surgery and transoral laser microsurgery required surgeons to use instruments that did not allow for wrist articulation, eliminated tactile feedback, and complicated two-handed surgery.
Robotic surgery has evolved as an adjunct to endoscopic and transoral surgery. Surgeons have found that having the ability to control the robot’s dual camera system and tubular endoscopic arms through a single console restores some of the fundamentals that were lost in conventional transoral surgery. Specifically, the surgical robot provides a magnified three-dimensional field of view, allows for tremor-free movement of graspers, cutting instruments, and needle-drivers with untiring action, and restores the ability to perform two-handed surgery.
History of Robotic Surgery
The term “robot” was introduced to the public by Czech author Karel Capek as a name for artificial people in his 1920 play “R.U.R.” (“Rossum’s Universal Robots”).4 Capek originally considered the term “labori” for his fabricated workers, but he settled on “robot,” which had its origins in the Czech words for “hard labor” and “drudgery.” Throughout the history of machines, people have conceived of “robots” either as automated instruments that relieve mankind of drudgery or machines that improve the quality of work. The evolution of surgical robots has followed a similar pattern.
The National Aeronautical and Space Administration (NASA) began development of a remote surgeon for orbiting astronauts in 1972. Researchers at the Stanford Research Institute furthered that work in an effort to improve minimally invasive surgery (rather than to perform remote surgery). The Defense Advanced Research Projects Administration (DARPA) expanded on the Stanford researchers’ work to develop a remote telesurgery unit that enabled surgical procedures to be performed on wounded soldiers in the battlefield. In 1995, Intuitive Surgical Inc. was formed to design a robot that could improve the surgeon’s capability. By the late 1990s, three surgical robotic systems were being used in academic institutions: the daVinci Surgical System made by Intuitive Surgical, and the Aesop endoscope robotic control system and Zeus robotic system made by Computer Motion. The first robotic surgery—a beating-heart coronary artery bypass graft procedure—was performed in the late 1990s using the Zeus system at the University of Pittsburgh. Today, Intuitive Surgical’s daVinci system is the only commercially available surgical robot.
The da Vinci robotic surgical aid has three components: a remote console, an instrument cart, and a wired vision cart. The surgeon sits at the remote console, where he or she manipulates the master controllers to move a binocular 0-degree or 30-degree camera and instruments. The instruments have 540 degrees of wrested rotation. The surgical instruments are attached to a cart that is positioned adjacent to the patient; they are placed in the surgical field by the surgeon before the procedure begins. The three-dimensional surgical view is recreated at the wired vision cart, where computer processing links the image seen by the surgeon on a monitor and the spatial relationships of the instruments in a virtual surgical field (Figure). Computerized motion scaling eliminates hand tremors and fatigue, and improves the surgeon’s ability to precisely position the instruments.
Although this system was not specifically designed for transoral procedures, it has proved useful and has advantages over other transoral techniques. In 2005, Hockstein et al. conducted a thoughtful and careful investigation proving the safety and feasibility of the daVinci surgical system for transoral access of the tongue base and supraglottic larynx.5-7 Weinstein and O’Malley later demonstrated that transoral robotic surgery (TORS) could be used both safely and effectively for removal of tumors of the base of the tongue and larynx, which had been done primarily by transoral laser microsurgery (TLMS).8,9 Since then, a number of other investigators have used TORS to remove head and neck tumors and achieve outcomes that rival those of traditional transoral surgical techniques.10,11
Although squamous cell carcinoma has been the primary target of robotic head and neck surgery, surgeons have also tested its efficacy for treating thyroid tumors, obstructive sleep apnea, parapharyngeal space tumors, and laryngeal pathology.
Robotic Surgery for Head and Neck Cancers
The current literature on use of the surgical robot in head and neck procedures is summarized in the table on page 39. The research includes case reports, studies of functional outcomes of surgery, and reports on oncologic data. The following is a brief look at how robotic surgery is currently being used to treat cancers of the head and neck.
■ Oropharynx
Since Hockstein reported on the technical feasibility of operating through the oral cavity with the da Vinci surgical system,5 the majority of cases that have used this approach have involved the oropharynx. Researchers have demonstrated that this approach is both feasible and has specific benefits. For example, Weinstein et al. demonstrated high local and regional control of squamous cell carcinoma using TORS, neck dissection, and adjuvant therapy in 31 patients.12 White et al. demonstrated similar disease control rates in a multi-institutional review of TORS for oropharyngeal (OP) squamous cell carcinoma.11 Important in these surgeries is the relatively high preservation of function, as more than 95% of patients were able to maintain an oral diet after completing treatment.10,12
■ Larynx
In 2005, the first case report of the da Vinci system being used in head and neck surgery described the excision of a vallecular cyst.13 Since then, surgeons have used TORS to remove lesions of the supraglottis, larynx, and hypopharynx.14-16 TORS has been used in these areas more than others because they are not easily exposed using oral retractors. As the surgeon goes beyond the base of tongue into the supraglottis, larynx, and hypopharynx, access becomes more difficult. As cameras and instruments become smaller, surgical robots likely will facilitate access to the inferior portion of the upper aerodigestive tract as well.
■ Parapharynx and Skull Base
Transoral robotic surgery has been used to excise benign lesions in the parapharyngeal space. Most of these lesions are prestyloid encapsulated benign salivary tumors. An article published in 2010 by O’Malley and colleagues describing a series of these surgeries reported that in seven of 10 cases, lesions were removed intact using this approach; two lesions demonstrated capsule dehiscence, and one patient was converted to an open approach.17 The authors concluded that the complication rate with this approach was comparable or superior to that of open procedures for removing parapharyngeal space tumors. They suggested that after further investigation, TORS might become the standard approach for treating tumors of the parapharyngeal space.
Lack of available rongeur and drill instruments limit the use of TORS to soft-tissue manipulation. The ability to control a camera and use two hands in the surgical field make the use of TORS for endoscopic skull-base surgery enticing. As new instruments are developed, the use of robotics for endoscopic skull-base surgery will likely increase.
■ Thyroid
Endoscopic thyroidectomy has seen varied acceptance at different institutions including Mayo Clinic Rochester, the M.D. Anderson Cancer Center, and the Medical College of Georgia. The motivation for using this approach is to minimize the surgical scar or to make the incisision in an area where a scar will not be visible. In 2009, Kang et al. demonstrated the feasibility, and, ultimately, the advantages of transaxillary robotic thyroidectomy in the treatment of well-differentiated thyroid cancer.18 Since then, other surgeons have applied this approach using Kang’s transaxillary method or other novel incisions.19,20
Robotic thyroidectomy currently takes longer than conventional thyroidectomy, even in the hands of experienced surgeons, and use of the procedure is limited by the size of the tumor, the gland, and the patient. Use of the procedure is expected to increase as surgeons become more experienced with the technology and as more and smaller instruments that can attach to robotic arms are developed.
■ Neck Dissection and Reconstruction
As robotic surgery has been applied to treatment of malignancies, differences in practice have arisen as to the management of the neck during resection of metastatic disease. When performing two different surgeries, some surgeons managed the neck after doing the first procedure in order to minimize communication of the pharynx and neck.8 Others have managed the neck while they are doing robotic pharyngectomy and have minimized the complications of communication with primary pharyngeal closure and drain management.21 Still others have used the robot to perform simultaneous local flap or microvascular flap reconstruction to eliminate pharyngeal-neck communication.22
An obvious extension of the current uses of robotic surgery would be minimally invasive robotic surgery of the neck. The feasibility of this has been demonstrated for the management of lateral neck metastasis from thyroid cancer;23 but to date, no one has published on using this technique for the management of squamous cell carcinoma.
The conclusion we can draw from these studies is that TORS is appropriate for managing select benign and malignant head and neck tumors. The advantages of TORS are similar to those of transoral laser microsurgery: less-frequent use of tracheostomy, shorter hospital stays, and decreased need for prolonged enteral feeding.10 Limitations are related to exposure of the tumor transorally and the type of patient who is eligible (eg, patients who are not obese). As the T-stage of the tumor increases, the applicability of this modality becomes more limited.
We have also learned that robotic surgery can be done through remote and hidden incisions that result in better cosmetic outcomes. This is especially important for patients undergoing thyroidectomy and neck dissection, which have traditionally been performed through incisions in the front of the neck. The safety and feasibility, oncologic outcomes, and functional outcomes of this surgery need further investigation.
Future Applications
There is no question robots have helped surgeons overcome the limitations of endoscopic surgery, improving their ability to see the structures of the head and neck and offering them a means to perform two-handed manipulations. Yet robotic head and neck surgery is still in the developmental stage. The size of current robotic surgical equipment hampers its use in the narrow confines of the head and neck. Its use is also limited by its instrumentation, as there are no fine cutting instruments or means to gently ablate tissue with a CO2 laser. The lack of instruments to drill or rongeur bone also limits its use in the paranasal sinuses and at the base of skull. Also, minimal-access surgery can be disorienting, as most head and neck surgeons are accustomed to having a wide visual field and the ability to see and manipulate the major neurovascular structures. With the integration of image-guidance, the development of haptic feedback, and the implementation of different lighting and tissue fluorescence capabilities—all of which are anticipated—the utility of the surgical robot in the operating theater will continue to grow.
Conclusion
Robotic surgery has advanced the capabilities of head and neck surgeons in a very short time period. As with other technologies, robotic surgery has gone from being used by a few earlier adopters to being used by many in daily practice. What is still needed is a balanced investigation with rigorous data analysis that fully explores the advantages and limitations of these robots. This will come as a result of multinational and multi-institutional clinical trials and data registries that ultimately will expand our knowledge and benefit our patients. MM
Eric Moore and Daniel Price are in the department of otolaryngology/head and neck surgery at Mayo Clinic.
References
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