Introduction
Robotic surgery provides enhanced visualization and maneuverability within the oropharynx and supraglottic larynx and enables a minimally invasive approach to lesions that would otherwise require conventional endoscopic or open transcervical resection. Advantages of transoral robotic surgery (TORS) include high-definition, magnified, three-dimensional (3D) visualization using 0 or 30-degree endoscopes and enhanced dexterity and surgical precision, potentiated by robotic EndoWrist instruments. Robotic instruments allow for maneuverability within a small space, reduce tremor, and have greater range of motion than the human hand. Notable drawbacks of the robotic system are lack of haptic feedback and distant positioning of the lead surgeon, which necessitates relying on the bedside assistant for maintaining patient safety and other important cues. Although use and indications are expanding, adoption of robotic techniques has been limited in pediatric otolaryngology due to perceived restrictions in oral access in younger, smaller pediatric patients and limitations in visualization of the larynx. Pilot studies for pediatric TORS emerged in 2007. , Since then, the limited literature on TORS in pediatric patients describes the common surgical indications, including lingual tonsillectomy for obstructive sleep apnea (OSA), benign oropharyngeal lesions, and laryngeal cleft repair. , Additional case reports describe TORS for oropharyngeal malignancy. , This small but growing body of literature establishes the safety and feasibility of pediatric TORS across multiple indications in patients as young as 0 to 3 months old. , , It should be noted that the use of TORS in children is not yet approved by the Food and Drug Administration, which should be addressed in the informed consent process.
In this chapter, and 
, the authors review indications and contraindications to help guide patient selection for beginning TORS surgeons, as well as to provide recommendations for anesthesia delivery, patient positioning, robotic docking, and surgical instrumentation. The goal of the authors is to further the adoption of safe robotic techniques and assist interested surgeons in developing a TORS program.
Transoral robotic surgery indications and contraindications
Robotic surgery was first described for transoral use in the early 2000s and was developed as a minimally invasive approach to oropharyngeal malignancies. Indications have since expanded to include benign and malignant pathologies of the upper aerodigestive tract both in adults and, more recently, in pediatric patients. Pediatric applications of TORS include lingual tonsillectomy for OSA (often after traditional adenotonsillectomy), excision of benign and malignant oropharyngeal and hypopharyngeal mass lesions, laryngeal cleft repair, and miscellaneous other pathologies in the head and neck.
The main contraindication to TORS is inadequate transoral exposure. Among pediatric patients, smaller size presents a challenge for TORS access. However, one advantage of pediatric anatomy is the more cephalad position of the pediatric larynx, which allows for easier reach of robotic instruments and exposure using standard oral retractors. Despite this advantage, an early study exploring feasibility of TORS among pediatric patients reported inadequate exposure for laryngeal cleft repair in three of five patients. Age has not been established as a contraindication, as multiple cases have been reported among patients younger than 3 months of age, with the youngest being 14 days old and the smallest weighing 2.5 kg. , , Among adults, attempts at predicting transoral exposure have included studies of anatomic biometric measures and cephalometric analysis of preoperative radiology; however, to date, no reliable predictors have been established. , Clinical experience and physical examination are used to predict feasibility. To date, no studies have been performed to predict exposure or other contraindications to TORS in pediatric patients.
Aberrant internal carotid artery anatomy is an important contraindication for oropharyngeal TORS procedures in adults. Though not directly relevant to the procedures listed in this chapter, this is an important consideration for future applications of TORS among pediatric patients, especially those with 22q11 deletion syndrome where medial position of the carotid arteries at the posterior pharyngeal wall can be encountered.
Anesthesia considerations
Prior to induction of general anesthesia, airway management should be discussed between the surgery and anesthesiology teams. Difficult airway status may be anticipated in the setting of obesity, oropharyngeal mass lesions, or anatomic factors including micro or retrognathia and macroglossia. Awake fiberoptic intubation may be considered in the setting of upper airway mass lesion though is rarely required for other benign pathology. Video laryngoscopy allows for clear visualization in most cases, even in the case of a difficult airway. Patients should be preoxygenated via mask inhalation prior to anesthesia induction. Patients with OSA or other causes of anatomic obstruction may require placement of a nasopharyngeal or oral airway to facilitate mask ventilation. Nasotracheal intubation is typically preferred for cases involving the tongue base, vallecula, and supraglottic larynx, while orotracheal intubation can be considered for accessing the posterior pharyngeal wall and posterior larynx. Nasal RAE tubes, taped and cushioned over the forehead, are preferred for unobstructed access to the oropharynx ( Fig. 60.1 ). Oral RAE tubes may be taped to the midline and positioned under the tongue blade, as is performed for tonsillectomy. Alternatively, a standard endotracheal tube may be used for orotracheal intubation and sutured laterally to the posterior oral tongue and retromolar trigone, allowing access to contralateral pathology. The endotracheal tube should be carefully secured prior to the patient being rotated 180 degrees from the anesthesiologist and introduction of robotic instrumentation.
Standard anesthetic monitoring is appropriate in most of the described cases, as all tend to be short (<4 hours) and have low expected blood loss. Invasive monitoring, including arterial line placement, is rarely needed. Preoperative type and screen is not routinely obtained by the authors. A fraction of inspired oxygen must be kept low (ideally below 30%) during the procedure to decrease the risk of airway fire during cautery. Intravenous corticosteroids and antiemetics are given at the start of the case to minimize airway edema and nausea. Glycopyrrolate may be used to decrease oral secretions. Paralysis facilitates optimal mouth opening and surgical site exposure. Short acting paralytics allow for rapid offset at the end of the procedure. Most patients can be safely extubated at the conclusion of the surgical procedure. Advantages of extubation in the operating room include avoidance of prolonged sedation and intubation and availability of equipment, personnel, and monitoring during extubation.
Patient positioning
Prior to turning the bed and robotic docking, the patient must be positioned for the duration of the case. A small shoulder roll may improve transoral exposure. Pressure points should be padded, arms are tucked to allow for docking of the robotic patient cart and placement of a mayo stand on each side of the bed, and a safety belt is placed across the hips. Eyes are taped shut and protected with goggles or shields. A molded tooth guard ( Fig. 60.2 ) is placed on the upper dentition (Aquaplast nasal splints, WFR/Aquaplast Corp., Avondale, PA). A figure of eight or mattress stitch is placed into the oral tongue for retraction. The tongue is retracted and mouth gag is placed (see Surgical Instrumentation below). The bed should be lowered to allow for adequate movement of the robotic arms. A patient warming device can draped over the patient prior to covering the patient with surgical drapes. Finally, a mayo stand is brought into place over the chest, and the mouth gag is suspended.
Robotic docking
Two robotic systems are currently in use in Otolaryngology—Head and Neck Surgery: da Vinci (Si, X, Xi, Sp; Intuitive Surgical Inc., Sunnyvale, CA) and the Flex Robotic System (Medrobotics Corporation, Raynham, MA). Both are FDA-approved for transoral use in adult patients. Use in pediatric otolaryngology is currently off-label. The da Vinci system is more widely used in otolaryngology and is thus the focus of this chapter. The single port (Sp) is the newest da Vinci system and was recently FDA-approved for transoral use in adults. Literature on use of this system in pediatric patients has not yet been published, and thus it is briefly mentioned in this chapter. The da Vinci system consists of the surgeon console, patient cart, and vision system. A secondary console may be used by trainees, enabling 3D visualization for both the surgeon and trainee and alternating control over the robotic arms.
To initiate docking, the robot arms should be raised to clear the patient on the operating table. The patient cart is driven to the bedside on the right or left side. The Si and X robots are parked at roughly a 15- to 30-degree angle from the base of the operating room table. Three arms are then manually extended to align with the mouth gag. A fourth arm can be moved aside. The middle arm is aligned with the midline of the oral cavity, and the right and left arms are positioned at approximately 30-degree angles to the sides ( Fig. 60.3 ). All three arms should be aligned parallel or cephalad to the tongue retractor. The Xi patient cart has a rotatable boom from which the arms are extended and thus can be parked with the base perpendicular to the bed. The boom can be manually positioned or automatically deployed (the authors use the preprogrammed “thoracic right” setting). After deploying the boom, the patient cart is driven toward the bedside so that the positioning laser is aimed at the open mouth. The arms are then extended and adjusted in the manner described for the Si robot. Once the arms are in place for all systems, cannulae and instruments can be inserted.
Once cannulae are inserted, the patient cart cannot be moved unless the instruments and cannulae are removed. The endoscope and two instruments are then inserted (see Surgical Instrumentation and Surgical Procedures below). The endoscope should be maximally advanced within the robotic arm cannula; the arm is then positioned with the endoscope almost touching the lesion. The endoscope is then withdrawn within the robotic arm to a working distance in the oral cavity. This technique allows for robotic arm placement as far from the patient as possible, maximizing working room for the instrument arms. The two instrument arms are placed with the cannula tip just outside of the mouth and the instruments are advanced until they are just inside the endoscope’s field of view. The operating room bed cannot be moved once instruments are in place within the mouth.
Surgical instrumentation
Instrumentation needed for pediatric TORS cases is listed in the box that follows. Selection of various retractors allows for exposure of the surgical site. The Crowe-Davis retractor is familiar to all pediatric otolaryngologists and may be used in most cases. The frame is open on one side, providing access for both the robotic arms and the assistant. The McIvor is less ideal as its closed frame limits access. The Dingman has a wider closed frame and includes cheek retractors and springs for suture securement. Flat tongue blades ( Fig. 60.4 ) allow for greater visualization and space, compared to blades with a groove to accommodate a midline endotracheal tube, and may be used with any of these retractors. Short blades allow access to the base of tongue, while longer blades improve access to the larynx. The authors typically use the Crowe-Davis retractor with flat Davis mouth gag blades (Integra ENT, Princeton, NJ). This blade has a gentle curvature that is ideal for approximating the curvature of the tongue and providing excellent exposure of the tongue base and vallecula ( Fig. 60.5 ). Flat blades are also made with dual suction ports (Davis-Meyer blades, Karl Storz, Tuttlingen, Germany). The Feyh-Kastenbauer (FK) (Gyrus Medical Inc., Tuttlingen, Germany) and Feyh-Kastenbauer-Weinstein-O’Malley (FKWO, Olympus) retractors are more complex regarding possible configurations, but allow for enhanced access to subsites including the hypopharynx and larynx, in addition to the base of tongue.
Patient safety
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Eye shields
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Moldable tooth guard
Mouth gags (all not necessary)
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Crowe Davis
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Davis Meyer tongue blades
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Davis mouth gag blade (Integra ENT)
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Dingman
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Feyh-Kastenbauer (FK)
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Feyh-Kastenbauer Weinstein-O’Malley (FKWO)
Robotic equipment
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0-degree endoscope
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30-degree endoscope (preferred for tongue base)
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Maryland forceps (± bipolar cautery)
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Permanent monopolar cautery spatula
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Large SutureCut needle driver
Assistant instrumentation
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Headlight
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Yankauer suction × 2
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Herd retractor
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Clip appliers as needed for hemostasis
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Long forceps
Suture
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2-0 Prolene on SH-1 taper needle (epiglottopexy)
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2-0 silk suture (tongue stitch)
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