The first application of robotics in otolaryngology was reported at Stanford University in 2003, where a group performed robotic assisted salivary gland surgery and neck dissection in a porcine model. The surgeons described the elimination of hand tremor and superior visualization as significant advantages of robotic surgery. Robot set-up time did not significantly slow down the operation; on average the required set-up time was 12.5 minutes. This group also observed that the normal lack of tactile sensation was compensated for by superior optics, which provided clearer views of the tissue planes.
The concept of TORS was established at the University of Pennsylvania, when Hockstein et al demonstrated wide access to the laryngopharynx using mouth gag retractors in an airway mannequin and cadaver. Weinstein et al later performed a supraglottic laryngectomy in a canine model. He demonstrated increased exposure with the mouth gag, with adjustable visualization of the larynx to facilitate the resection, a technique not possible with conventional TLM.[27,28] Additional series from this institution in canine and cadaver models provided information regarding use of five-mm instruments and other mouth retractors, which established a foundation to begin live human patient operations.
The first supraglottic laryngectomy in a single patient using robotic assistance with a CO2 laser was reported by a group from the Cleveland Clinic in 2007. While they showed the ability to incorporate the CO2 laser with the robotic arm, they also demonstrated the importance of evaluating variable patient factors such as oral opening and neck extension; failure to adequately evaluate these factors led to aborting two attempted robotic laryngeal resections in their series.
The first case series of patients undergoing TORS for OPSCC was reported from the University of Pennsylvania. Three patients with early stage, base of tongue squamous cell carcinomas (2 T2, 1 T1) had complete en bloc resection of their tumors with negative margins. No immediate complications were noted and patients were able to return to a full diet within six weeks of surgery. With the feasibility of TORS established in OPSCC, institutions have begun recruiting patients for clinical trials to compare efficacy with traditional TLM and radiation therapy with or without chemotherapy.
Oncologic and Functional Outcomes
Long-term oncologic outcomes of TORS are not possible at this point because of the relative infancy of the procedure. However, several institutions have published short-term data from small series, and this data is promising.
Surgeons at the University of Pennsylvania reported a phase I study of 27 patients with early-stage tonsillar squamous cell carcinoma undergoing TORS in 2007. Negative margins were attained in 25 of 27 patients and the two patients with positive margins were later cleared. Local control was achieved in all patients at six months follow-up. One patient developed distant metastasis.
Three other institutions have also reported their data on the efficacy of TORS for OPSCC. These institutions reported achieving negative margins of resection in patient series ranging from 20 to 45 patients.[33-35] In the Mayo Clinic series, 12 of 45 patients (27%) were able to avoid adjuvant radiation, and at one-year follow-up in this series, no local recurrences were detected.
Functional evaluation of organ-preserving minimally invasive techniques involves the preservation of swallowing and airway function without long-term dependence of enteral feedings and tracheotomies. The University of Alabama at Birmingham evaluated functional outcomes in 54 patients undergoing TORS. They found only five of 54 patients needed temporary tracheotomy, with decannulation occurring at a mean of eight days. 69% of patients initiated an oral diet after TORS and did not require enteral feedings. Only nine patients required a gastrostomy tube at the end of the study period and a statistically significant association was found with T4 stage primary site disease and primary disease located in the oropharynx or larynx.
Similar functional data was seen in the series reported by Moore, et al at the Mayo Clinic. His group reported tracheotomies in 31% (14 of 45) of patients, with average time to decannulation seven days. 48% (22 of 45) of the patients had feeding tubes and all but five patients had their tubes out within 20 days. The other five patients had their feeding tubes removed by four months after surgery.
These early evaluations of the oncological and functional outcomes of TORS illustrate a minimally invasive technique that permits resection of the tumor en bloc while preserving patients’ swallowing ability. The promising results of the data from these multiple institutions led to FDA approval of TORS for use in selected benign and malignant tumors of the head and neck in December 2009. Using transoral techniques, a mandibulotomy and/or pharyngotomy is avoided. As additional information regarding HPV status in patients undergoing primary surgical therapy emerges, TORS may play a significant role in the application of surgery as the first and possibly only treatment for select patients with OPSCC.
At institutions where robotic surgery has only recently been introduced, skeptics point to the significant costs associated with performing robotic-assisted cases. The console itself costs approximately 1.5 million dollars and requires at least one hundred thousand dollars in annual maintenance fees. Disposable equipment such as graspers, cautery arms, and other surgical instruments total approximately two hundred dollars per case.[10, 15] A recent cost analysis at a single institution showed that a hospital will lose money if fewer than 78 robotic prostatectomies are performed annually.
Implementation of a robotic program solely for TORS is unlikely at any institution because of the low volume of existing cases. However, at higher volume centers where the robot console is used primarily for urology and general surgery, a head and neck surgeon may add to the value of the robot by performing additional procedures each year.
With the popularity of robotic surgery growing and more patients demanding robotic surgery as part of their treatment, practitioners are seeking out training and certification in this area. Currently, Intuitive Surgical provides a training curriculum on their website that details a curriculum involving didactic lectures on the daVinci console, cadaver dissections, and live case observation. Representatives for the company will also provide surgeon proctoring during a practitioner’s initial procedures.
As more and more training programs perform robotic surgery, the implementation of a standardized curriculum into residency and fellowship education will be vital. The University of Medicine and Dentistry at New Jersey recently published a robotic training module for its otolaryngology residents. The authors found that performing simple tasks such as grasping inanimate objects and suturing on latex introduces residents to basic robotic surgical skills, easing their transition to live patient cases. As a result, many training programs now provide cadaver dissection courses using the robot as part of their training.
With the knowledge that TORS is a safe, efficacious procedure to use in head and neck oncologic surgery, attempts at using TORS in innovative ways and in other areas in the head and neck are now being reported. For example, as finer, more flexible instrumentation is developed, transoral robotic-assisted surgery on the glottic larynx can be more easily accomplished. Current instrumentation is too bulky to access the narrow space of the glottis.
Another intriguing and increasingly popular area of application for robots is in transaxillary thyroidectomy. Avoiding an incision in such an aesthetically important area as the neck while still being able to safely and fully remove the thyroid gland is an attractive alternative to many patients. In Korea, Dr. Chung popularized this procedure, with his report of over 300 patients. After assessing its feasibility in cadavers, we have also adopted this procedure at our institution. The success of this procedure may revolutionize minimally invasive neck surgery, especially as surgeons attempt to transition this technique to cervical lymphadenectomy.
Another application for robotics is in the field of skull base surgery, which requires precise motions with a steady hand, an advantage of robotic arms. Surgeons at the University of Pennsylvania illustrated an approach to the midline and anterior skull base using two trocars inserted transcervically and placing the camera head in the oral cavity. They were able to successfully perform dissections of the skull base in canine and cadaver models. At M.D. Anderson, the regions of the anterior skull base and sella were accessed and dissected via bilateral Caldwell Luc incisions and maxillary antrostomies. Both groups found precision dissection with improved dural repairs without a natural tremor.
A more recent trend in robotic-assisted surgery is in microvascular free tissue transfer. Microvascular anastomosis with non-tremulous arms has been shown to be faster and more effective. Introduction of a free flap into a large oropharyngeal defect provides improved functional recovery and avoids the need for long-term healing by secondary intention of the oropharyngeal defect.[43,44] The flexibility of the robotic arms also allows suture placement transorally in areas of decreased visibility using traditional open methods.
Robotic surgery in head and neck oncology is an exciting innovation that provides significant advantages. Patients have an en bloc removal of their tumors via a minimally invasive surgery without a cervical incision, while preserving function and potentially avoiding adjuvant radiation and its long-term sequelae. While long-term oncologic and functional data are needed to fully validate its use, early results are promising.
Financial Disclosure: The authors have no significant financial interest or other relationship with the manufacturers of any products or providers of any service mentioned in this article.