B-ENT, 2015, 11, Suppl. 24, 45-50 Transoral robotic surgery for base of 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 , tongue, and .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 (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 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

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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 (), 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

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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. We were treated with this modality between 2010 and routinely use fibrin glue on the wound bed to help 2011, there was a significant reduction in mean with hemostasis and reduction of granulation tissue. hospital stay (4.8 days versus 7.2 days), average We routinely extubate patients immediately after cost to patients and the need for a tracheostomy surgery; they are subsequently either sent at the when compared to patients undergoing other types post-anesthesia care unit (PACU) for observation of surgery (n = 747). The need for a gastrostomy during one night or at the ward, depending on tube was however increased in subjects who several factors such as the length of surgery, underwent TORS reduction. A major limitation of patient’s anatomical features, post-operative edema this study was the lack of data on the resection and risk of bleeding. All patients are administered margin. Previously published work had shown that broad-spectrum antibiotics and pain relief. Oral positive margins can be seen in 0-7% of cases. The intake is commenced the next day and patients lack of tactile feedback may contribute to difficulty discharged shortly thereafter. in assessing adequacy of the resection margin. Postoperative complications including death, peri­ operative hemorrhage, inpatient blood transfusion, Tongue base malignant neoplasms aspiration pneumonia, wound breakdown, fistula, The majority of BOT malignancies are squamous re-intubation and dysphagia were similar between cell carcinomas (SCCs) and are thereafter followed open surgery and TORS. However respiratory in frequency by minor tumors. events such as respiratory failure/insufficiency and According to the US National Cancer Database, the respiratory arrest were significantly higher in the majority of subjects between 1985 and 1996 TORS group. underwent open surgical resection for BOT Tongue base surgery with TORS does provide neoplasms. However, despite cases where local some challenges too. The need to secure the airway control was achieved, the subsequent effects on the varies according to the practice of each center. quality-of-life and functional outcome were poor. Mercante et al.2 performed 13 such cases for both In these subjects, long-term tracheostomy and benign and malignant conditions. All patients were gastrostomy tube placement was routinely used tracheotomised prior to performing TORS (for 6 which resulted in significant speech and swallowing days in total) and all resection margins were clear. problems. After 2001, the focus on organ This policy was felt to be safe and avoided any preservation with the hope of function preservation risks to the airway in the peri-operative period. were felt to be superior using chemoradiotherapy There was also an opinion that the lack of any (CRT). Although the use of CRT has been shown to anesthetic tube around the operative field improved achieve good local control and low distant visualization and hence success of resection metastases rates, toxicity has become the major margins. On the other hand, many other surgeons problem. Toxicity from CRT is becoming more do not routinely perform ‘tracheostomies’ and elect evident over time.2 In addition, speech and for overnight to 48 hours post-operative intubation swallowing were also affected by CRT with higher instead. incidences of permanent tracheostomy or The need to perform a neck dissection is also gastrostomy. controversial. Mercante et al. performed a neck The published literature confirms that surgical dissection in the same sitting in 7 out of 13 subjects.2 resection with negative margins is directly related In 79 patients who underwent TORS for a variety

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of oropharyngeal malignancies, Richmon et al. cohort of 22 patients, the primary site was found to reported no causative relationship between a be the palatine tonsil in 59.1% of the subjects and concurrent neck dissection and the length of stay or BOT in 18.1%. They reported that utilizing TORS postoperative complications.10 Indeed it was of their in treatment and diagnosis of CUP could increase practice that a neck dissection can be performed at the diagnostic ability of standard modalities by as the same time. much as 18.1%. An additional advantage cited was In the postoperative period, swallowing function that the excision biopsy for CUP often was also the needs to be evaluated carefully. Pain management definitive therapy for the BOT malignancy. and early introduction to oral feeding should be Patel et al.15 performed TORS tonsillectomy and instituted. Hemorrhage after surgery has been BOT surgery in 18 patients out of a cohort of an reported up to even 14 days later necessitating the original 47 with CUP. This group of 18 patients, need for close monitoring of these patients. despite having been thoroughly investigated with Besides SCCs, TORS has been used to resect all established diagnostic modalities failed to other tumor types such as minor salivary gland demonstrate the site of the primary. Thirteen of tumors, cribriform adenocarcinomas and adenoid these patients were found to have a primary cystic carcinomas.11,12 thereafter (7-BOT, 5-tonsil, 1-both BOT and tonsil). Chung et al. also discussed the relative ease of Byrd et al.16 evaluated the cost effectiveness of TORS in BOT surgery compared to anterior tongue robotic surgery on 22 subjects who underwent neoplasms. They could not demonstrate the TORS for an unknown primary. In 16 out of advantages of TORS in easily accessible areas 22 subjects, the primary was found in the tongue using traditional surgical methods.9 base and in 3 out of 22 subjects the primary was found in the tonsil. The diagnostic success rate of Carcinoma of Unknown Primary (CUP) TORS was reported as 86.4%. The authors Tongue base surgery using TORS has also been suggested the use of TORS in subjects in whom the found to help in the evaluation of patients with an examination under general anesthesia and unknown head and neck primary. tonsillectomy did not demonstrate the primary. If Despite the use of positron emission tomography the examination under general anesthesia and with computer tomography (PET-CT) and TORS resection were performed in the same session panendoscopy with directed biopsies under general as an initial diagnostic tool, the procedure increased anesthesia (e.g. nasopharynx, tonsil, BOT, piriform the incremental cost effectiveness ratio of US$8619 sinus), the percentage of unknown primaries can be per procedure.16 as high as 45% to 63% of subjects. The identification of the occult primary in CUP can increase survival Benign lesions of BOT rates from 58% to 100%.13 Another benefit of Transoral robotic surgery for the BOT has also detecting the site of the primary is to focus been used successfully in other conditions including radiotherapy and in so doing protecting surrounding several successful reports of thyroglossal duct cyst structures from unnecessary toxicity. (TGDC) excision both in infants and in adults. The vast majority of unknown primaries are Kayhan et al.17 reported a 2-year old infant who found in the tonsil and tongue base. Visual underwent complete removal of the cyst located examination of oropharyngeal region under close to the BOT and vallecula. Kimple et al. also magnified 3-D vision may facilitate the detection of reported a TGDC resected with TORS on a 45 year a malignant lesion in covert areas.14 Mehta et al.13 old women.18 Transoral robotic surgery has been reported 10 patients with CUP in whom traditional used successfully to resect small vascular lesions of diagnostic modalities (ENT examination, PET-CT the BOT with minimal morbidity.19 and directed biopsies including bilateral palatine tonsillectomy) had failed to demonstrate the Important considerations primary. All 10 subjects underwent BOT resection with TORS. In 9 out of 10 subjects the primary was Transoral robotic surgery BOT reduction is found in the BOT with a mean diameter of 0.9cm.13 performed for several different indications. Careful Durmus et al.14 used TORS in both tonsillectomy patient selection is essential for achieving success. and BOT resection for the diagnosis of CUP. In the Oncological procedures were generally performed

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on early stage cancers, namely T1 and T2. As fortnight later, a risk the patient should be described before, a detailed history, physical adequately warned about. examination, diagnostic assessment and The average length of stay (LOS) varies understanding the need for adequate access for the according to the institution. In general the factors robot within the oropharynx make TORS less likely that affect the length of stay are the surgeons’ to fail. Patients should be provided the pros and preference, the patency of the airway, the subjects’ cons of TORS and other treatment modalities to be oral nutrition status, pain status and drain able to make a proper informed choice and consent. management. Most institutions prefer a hospital Transoral robotic surgery is performed from inside stay that ranges from 2 to 7 days. However Richmon to outside. In that regard, the surgeon who is adept et al.10 reported a 1.5 day LOS and reported that at operating in open conditions needs to be familiar early discharge did not affect postoperative with an anatomy that is reversed. The recognition complication rates. In their report the LOS was of important landmarks and neurovascular unaffected by the nature of the lesion (benign structures takes time and this learning curve benefits versus malignant), the subjects’ age or concurrent from cadaveric, animal and supervised proctorship neck dissection. in live subjects. The TORS approach is different Transoral robotic surgery brings some additional from the other transoral approaches in that the costs. Recent publications have started to system does not provide tactile feedback and demonstrate that it can be a cost effective technique.9 therefore the surgery is intuitive. When resecting Cost effectiveness is a multifactorial issue with the BOT, it is prudent to start in the midline (if the obvious and less tangible costs such as the surgeon’s tumor is in such location) where there are no comfort, the ease and accessibility of the system to important neurovascular structures and be more hidden areas decreasing surgical time, conservative in the scope of resection to avoid minimizing the need for additional therapy and complications; however, as previously emphasized, patient satisfaction. if the tumor happens to be located in the lateral aspect of the BOT, care should be taken to carefully Conclusion dissect and identify the vessels coursing laterally in order to avoid major bleeding during tumor resection. In addition, the extent of resection should Transoral robotic surgery with the da Vinci surgical be weighed up against the important role of the system offers a new way to perform base of tongue BOT in the second phase of swallowing.5 surgery. This modality is relatively new with only a Transoral robotic surgery for the BOT is an 5-year history. Inıtial publications have shown its evolving modality. Opinions in management vary feasibility and safety for various indications according to practices and resources. Tracheotomy­ including both benign and malignant BOT insertion for instance is debatable and as described conditions. This technique does also have some earlier has its advocates and detractors. The disadvantages that need to weighed-up objectively. approach to surgery for neoplasms and sleep apnea Further prospective studies, multi-center collabo­ differs in several ways. The goal in oncological ration with long-term follow-up of quality of life, surgery is to achieve negative surgical margins. function and objective outcome measures will The introduction of oral intake differs from one provide a better understanding of the benefits this institution to another and may vary from 1 to 10 exciting surgical modality may provide. days. Early re-start was postulated as a predisposing factor for postoperative complications such as References aspiration, fistula and bleeding. However, Richmon et al. did not report that early feeding was as a 1. Friedman M, Hamilton C, Samuelson CG, Kelley K, potential contributor to postoperative complica­ Taylor D, Pearson-Chauhan K, Maley A, Taylor R, tions.9 Venkatesan TK. Transoral robotic glossectomy for the treatment of obstructive sleep apnea-hypopnea syndrome. In general, postoperative complication rates for Otolaryngol Head Neck Surg. 2012;146(5):854-862. TORS range form 13% to 31%. The overall 2. Mercante G, Ruscito P, Pellini R, Cristalli G, Spriano G. bleeding rates differed range from 0.5% to 10.4%.7 Transoral robotic surgery (TORS) for tongue base tumours. Hemorrhage postoperatively can be seen up to a Acta Otorhinolaryngol Ital. 2013;33(4):230-235.

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