Transoral robotic surgery to resect skull base tumors via transpalatal and lateral pharyngeal approaches

Abstract

Robot-assisted surgery in the field of head and neck has been gaining popularity due to appeal in using minimally invasive approaches, obtaining excellent visualization, and overall low risk. Reports among multiple different specialties have also shown reduction in surgery duration, recovery time in the intensive care unit, and overall time of hospitalization stays when compared to classic open procedures.1 Techniques for resecting skull base cancers are traditionally performed through large incisions and require mobilization of large amounts of tissue. Transoral robotic surgery (TORS) may provide a more accurate means to treat head and neck and skull base cancer, while allowing for decreased levels of morbidity and decreased levels of adjuvant radiation and chemotherapy. Reports on the development of the TORS application to anterior skull base masses have previously been described in small case descriptions in preclinical, experimental, canine and cadaver models using transcervical or suprahyoid ports.2-4 Subsequently, TORS was applied to a small case series and feasible in nine of 10 patients with parapharyngeal space tumors with no carotid encasement or bone erosion.5 The objective of this study is to discuss feasible approaches using transoral robotic surgery (TORS) to access the anterior and lateral skull base and describe a novel approach for nodal dissection in the retropharyngeal space. The da Vinci surgical robot (Intuitive Surgical, Inc., Sunnyvale, CA) was used on four patients for complete resection of skull base tumors. The da Vinci surgical robot has been approved by the US Food and Drug Administration for resection of T1 and T2 oropharyngeal cancers. We applied robotic technology for off-label use to resect skull base tumors. The pathologic diagnosis was two pleomorphic adenomas in the parapharyngeal space, one pleomorphic adenoma in the infratemporal fossa, and one metastatic papillary thyroid cancer node in the high retropharyngeal node basin. Details on patients included in the study are shown in Table I. A transpalatal approach was used to access the infratemporal fossa (n = 1) and retropharynx (n = 1). Lateral pharyngotomies were performed to access parapharyngeal spaces (n = 2). All mucosal incisions were closed primarily. TORS was performed on four dentate patients (3 male; mean age, 51 years; age range, 36–78 years) who had an anterior and lateral skull base lesion (Table I). All patients were place in the supine position with a shoulder roll and underwent general endotracheal anesthesia. The reinforced endotracheal tube was secured laterally in the oral cavity, depending on the site of mass. The operating table was rotated 180 degrees away from the anesthesiologist's field. Prior to TORS, all patients were examined under direct rigid laryngoscopy using a McIvor mouth gag for adequate exposure. Once the site of the mass was identified, the da Vinci surgical robot was introduced in the surgical field. The articulating robotic arms were positioned intraorally, along with the 0° or 30° endoscope. With robotic control, the endoscope was manipulated to provide visualization of the oral cavity and pharynx. To obtain adequate access to the anterior and lateral skull base spaces, either a Bovie cautery or CO2 laser was used to dissect tissue in the posterior oral cavity or oropharynx. Two patients with pleomorphic adenomas in the lateral parapharyngeal space required lateral pharyngectomies. Partial pharyngectomies were performed with the aid of the robot. The patient with a pleomorphic adenoma in the infratemporal fossa and the patient with a metastatic papillary thyroid cancer node in the retropharynx required a lateral transpalatal approach. Palate resection with dissection of the soft palate to the level of the lateral glossopharyngeal fold was accomplished with the aid of the robot, as well as manual aid from the bedside assistant. Adequate exposure was obtained throughout the case, and the internal carotid