B-ENT, 2015, 11, Suppl. 24, 45-50 Transoral robotic surgery for base of tongue neoplasms I. Sayin, R. Fakhoury, V. M. N Prasad, M. Remacle and G. Lawson Department of Otolaryngology – Head and Neck Surgery, CHU Dinant Godinne, 5530 Yvoir, Belgium Key-words. Transoral robotic surgery; base of tongue; unknown primary; benign; malignant; neoplasm Abstract. Transoral robotic surgery for base of tongue neoplasms. Surgery to the base of tongue (BOT) in the presence of neoplasm is a challenging topic for head and neck surgeons. This area is difficult to access and includes important neurovascular structures such as the hypoglossal nerve and lingual artery. The pivotal role of the tongue base in swallowing makes planning the surgical approach more challenging. The surgical approaches vary from open neck/mandibulotomy to transoral laser surgery (TLS) which have significant disadvantages. After introduction of transoral robotic surgery (TORS) to otolaryngology practice with the da Vinci Surgical system, we have in our armamentarium a new approach to the BOT. The improved exposure with new retractors, 3-dimensional (3-D) visualization and magnification and advanced motion capacity allow for increased ease to perform surgery in this difficult area. In recent years, several articles published the data about safety and feasibility of TORS for various conditions. This article presents our approach to the BOT for neoplasms including malignant and benign lesions. Introduction years. In this review article, we aim to provide the current state of surgery using TORS in the Transoral robotic surgery (TORS) with the da Vinci management of BOT (base of tongue) neoplasms. Surgical System (Intuitive Surgical, Sunnyvale, CA) was first introduced in 2005. In 2009, the FDA Anesthetic and pre-operative considerations approved its use in benign and malignant diseases of the palatine tonsil, tongue, pharynx and larynx.1 It is generally accepted that subjects with low Transoral robotic surgery is a relatively novel anesthetic risk are good candidates for TORS. method to perform minimal invasive surgery. The Subjects who are in high risk have to be evaluated robotic da Vinci Surgical system includes a carefully and the decision have to be made on 540-degree motion capacity of robotic arms and an individual basis. A history of previous difficult excellent 3-dimensional (3-D) magnified view of intubation needs to be elicited. the operating field. The potential tremor of the What is critical in performing TORS is the need surgeon’s wrist is filtered by the robotic system. for adequate exposure of the target tissue. Both hands are used simultaneously and the robotic Maintaining exposure requires one of a variety of arms left in the surgical field. The two major devices that hold the mouth open and tongue problems with the system are the lack of tactile depressed. This can be achieved with either a feedback and relatively high cost. traditional type of mouth gag (e.g. Boyle-Davis) Transoral robotic surgery should be regarded as or with a more advanced device such as the an advanced modality of performing traditional Feyh-Kastenbauer (FK) retractor (Gyrus ACMI, transoral surgery which head and neck surgeons Southborough, MA) or LARS (Laryngeal advanced were familiar often with the use of lasers.2 Our long retractor system, Fentex, Tuttlingen, Germany). experience and familiarity with the laser in the oral Exposure using an FK retractor is found to be cavity and pharynx allowed us to adopt TORS in superior to traditional mouth gags especially for Ear Nose and Throat (ENT) practice quickly. We visualization of regions like the BOT. Correct performed mainly oncological procedures initially positioning of the retractor allows the surgeon to but over time began to perform non-oncological clearly see the epiglottis in the midline behind the ones. We believe that the future development of BOT along with either side of the valleculae. robotic systems and our understanding about their Inadequate visualization may lead to an increased capability will continue to evolve in the forthcoming risk to adjacent structures, inadequate tissue/tumor sayin-lawson-.indd 45 14/12/15 09:03 46 I. Sayin et al. removal, abandoning the procedure or conversion present, the surgeon is faced with a more difficult into an open procedure (1-5%) – all of which are appreciation of the important and laterally placed related with poor surgical outcomes. Limited mouth structures. Hence, tongue base surgery should be opening invariably affects visualization of the BOT performed carefully and in many cases, benefits and epiglottis. It is reported that TORS cannot be from good quality radiological support both in the performed in 7 to 26 percent of subjects due to type and quality of images and radiological report. inadequate exposure.3 Cephalometric analysis has All robotic procedures were performed under been advocated by some4 to decide on suitability general anesthesia. We did not perform a routine for TORS although in the main, the decision is tracheotomy. Trans-nasal intubation made with a made after a thorough physical examination. The laser-resistant tube (size 5.5-6) was performed in physical factors that may preclude accessibility for all subjects. The subject was supine with the TORS include prominent front teeth, rigid short anesthesiologist and ventilation equipment placed neck, wide neck circumference, peripheral soft at the patients ‘feet. The subject’s eyes were tissue and a retrognathic small mandible. Subjects protected with sterile drapes and the teeth were who have one or more risk factors need to be protected with a dental guard. evaluated carefully. It is recommended that an We preferred to protract the tongue with two inter-incisive distance of more than 1.5 cm is sutures passed through the anterior part of the preferable. tongue for better visualization of the BOT. The da Vinci Surgical system was set up thereafter. We Surgical Considerations used an FK or LARS (larynx advanced retractor When the BOT is the anatomical area of interest, system) retractor to expose the BOT. The LARS is the surgeon should be familiar with its complex better adapted to human anatomy as well as the anatomy and aware of the landmarks not only for features of the robotic arms and as such allows for open surgery but also for endoscopic approaches sufficient visualization of the tongue base and where important neurovascular structures are epiglottis. Specifically, this retractor is provided present. Vicini et al. had mentioned that based on with a large choice of blade shapes and thus allows their experience, the BOT possesses no safe to properly expose lateralized tongue base tumors. landmarks during dissection.5 They noted that the The da Vinci Surgical System’s manipulator unit rich vascular arterial network reaching the midline was set up on the left side of the patient. The 8-mm needs to be regarded as an “anatomical plane”. 30-degree da Vinci 3-D robotic camera and two Tongue base surgery performed in the midline is instrument arms were introduced into the oral traditionally regarded as safe. There are no major cavity. For BOT reduction, a 5-mm EndoWrist® neurovascular structures present in this area. The Schertel grasper was placed at the left arm console BOT is bounded anterosuperiorly by the while a 5-mm EndoWrist® monopolar cautery with circumvallate papilla and the posterior aspect of the a spatula tip or Maryland dissector was placed into oral cavity, inferoposteriorly by the vallecula and right. Grasping was thus achieved with the Schertel lingual surface of epiglottis, and laterally by the grasper; the dissection with the Maryland dissector glossoepiglottic folds. Tongue musculature or with the monopolar cautery tip that could also be includes both intrinsic and extrinsic muscles; since used for coagulation. The second surgeon who is the mucosa of the base of the tongue contains seated at the head of the patient provided suction squamous epithelium (along with small dorsal when necessary. Surgical resection can also be lingual arteries), minor salivary glands, and performed with a laser.7 A thulium-doped YAG lymphoid tissue (lingual tonsils), malignant laser system (Revolix; Lisa laser products) has been neoplasms may arise from these tissues. Deeper used and recommended for the da Vinci Surgical dissection in the midline leads to the hyoid bone. system. The main lingual artery is found laterally and under Visualization of the epiglottis is important for the hyoglossus muscle. Further lateral to the surgical orientation. The midline of the tongue base hyoglossus muscle lies the hypoglossal nerve with and its lateral aspects were identified. The resection its own vascular supply.6 Surgery performed in the commenced at the midline in a methodical manner midline is therefore safest for tongue base reduction. with special care paid to the intrinsic muscles and However when there is bulky lymphoid tissue bleeding. The resection was performed in a sayin-lawson-.indd 46 14/12/15 09:03 TORS in BOT neoplasms 47 triangular manner in which the apex of the triangle to disease free survival rates. Hence, with the is located at the BOT in the midline. If the tumor advantages derived from TORS in BOT happens to be located in the lateral aspect of the malignancies resection using this modality should BOT, care should be taken to carefully dissect and confer this success. In addition, complete resection identify the vessels coursing laterally in order to will reduce the need for additional CRT. O’Malley avoid major bleeding during tumor resection. et al. demonstrated their findings in 3 subjects after Frozen sections around the resection margins are having developed their familiarity with TORS on invariably sent. animal and cadaveric models.8 In the largest Hemostasis with clips and/or cautery was available series of TORS in BOT surgery by Chung instituted after completion of the surgical resection et al.,9 it was reported that of the 147 patients who and all frozen sections were deemed to be clear.