Robotic surgery in pediatric otolaryngology—head and neck surgery

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 Video 60.1 , 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.