Transoral robotic surgery (TORS) offers a minimally invasive approach to the pharynx with a magnified 3-dimensional view, wristed instruments with 7 degrees of freedom, and tremor filtration. TORS affords an excellent approach to benign lesions of the pharynx. This article is grouped into subsites of the nasopharynx, oropharynx, and hypopharynx, addressing patient setup, surgical technique, and postoperative management of each subsite. Although TORS has been described primarily for resection of malignant lesions of the pharynx, the setup, exposure, and anatomy described herein are identical for benign lesions, the difference being the magnitude of resection.
Key points
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TORS for benign pharyngeal lesions follows similar operative set-up and technique as for malignant lesions, often with less destruction of normal tissue.
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Placement of tracheotomy and gastrostomy tube are not expected.
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One much always consider the location of the dorsal lingual artery and carotid artery.
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Placement of a nasogastric feeding tube is recommended if a palatal split approach is utilized.
Introduction
The first robotic system, known as the Automated Endoscopic System for Optimal Positioning, was approved by the Food and Drug Administration (FDA) in 1993. It provided a robotically controlled arm to manipulate an endoscope for laparoscopic surgery. This system subsequently evolved to the development of the da Vinci Surgical System (Intuitive Surgical, Inc, Sunnyvale, CA, USA), which was FDA approved for abdominal laparoscopic surgery in 2000 and more recently for transoral otolaryngology surgical procedures restricted to T1 and T2 benign and malignant lesions in 2009.
The da Vinci robot consists of several key components: the surgeon console, the patient-side cart, the vision system, and the endowrist instruments. The surgeon console provides a 3-dimensional (3D), high-definition image of the operative field and the master controls for the robotic arms and video endoscope. It is positioned at a distance from the patient. The patient-side cart is positioned next to the patient and includes 3 or 4 robotic arms delivering the surgical instruments and video endoscope. This robot is a master-slave system and surgeon input is required for all robotic movement. The vision system includes a 3D high-definition 0° or 30° endoscope coupled to an image-processing tower and monitor for the operating room staff and assisting surgeon. The endowrist effector arms are articulating wristed instruments with 7 degrees of freedom in both 8-mm and 5-mm sizes. The operative table is typically rotated so the patient’s head is opposite from the anesthesia cart. The patient is appropriately relaxed to allow for the placement of a mouth gag and suspension. Dental protection is recommended. Three of the robotic arms (scope in the center flanked by right and left 5-mm effector arms) are advanced through the mouth. A 0° or 30° scope can be used for tonsil resections and a 30° scope affords optimal visualization of the tongue base and hypopharynx. The assisting surgeon sits at the head of the bed and uses an instrument (typically a suction, cautery, retractor, or clip device) in each hand. This configuration allows for 2 surgeons and 4 instruments working at the same time in the pharynx.
Transoral robotic surgery (TORS) provides the surgeon with a 3D, high-definition view of the operative field from the perspective of being inside the mouth of the patient. The maneuverable scope affords a wide field of vision. The wristed instruments with tremor-filtration, motion-scaling, and 7 degrees of freedom provide precise bimanual tissue manipulation in areas heretofore inaccessible through the mouth, allowing for en-bloc excision and complete visualization of large tumors through the mouth and obviating an external approach and cervical scar. A frequently cited limitation of the robot is the lack of haptic feedback, which many experts feel is compensated for by the superior 3D vision. For the purpose of this article, the use of TORS is examined in the treatment of benign lesions of the pharynx, subdivided into the nasopharynx, oropharynx, and hypopharynx.
Introduction
The first robotic system, known as the Automated Endoscopic System for Optimal Positioning, was approved by the Food and Drug Administration (FDA) in 1993. It provided a robotically controlled arm to manipulate an endoscope for laparoscopic surgery. This system subsequently evolved to the development of the da Vinci Surgical System (Intuitive Surgical, Inc, Sunnyvale, CA, USA), which was FDA approved for abdominal laparoscopic surgery in 2000 and more recently for transoral otolaryngology surgical procedures restricted to T1 and T2 benign and malignant lesions in 2009.
The da Vinci robot consists of several key components: the surgeon console, the patient-side cart, the vision system, and the endowrist instruments. The surgeon console provides a 3-dimensional (3D), high-definition image of the operative field and the master controls for the robotic arms and video endoscope. It is positioned at a distance from the patient. The patient-side cart is positioned next to the patient and includes 3 or 4 robotic arms delivering the surgical instruments and video endoscope. This robot is a master-slave system and surgeon input is required for all robotic movement. The vision system includes a 3D high-definition 0° or 30° endoscope coupled to an image-processing tower and monitor for the operating room staff and assisting surgeon. The endowrist effector arms are articulating wristed instruments with 7 degrees of freedom in both 8-mm and 5-mm sizes. The operative table is typically rotated so the patient’s head is opposite from the anesthesia cart. The patient is appropriately relaxed to allow for the placement of a mouth gag and suspension. Dental protection is recommended. Three of the robotic arms (scope in the center flanked by right and left 5-mm effector arms) are advanced through the mouth. A 0° or 30° scope can be used for tonsil resections and a 30° scope affords optimal visualization of the tongue base and hypopharynx. The assisting surgeon sits at the head of the bed and uses an instrument (typically a suction, cautery, retractor, or clip device) in each hand. This configuration allows for 2 surgeons and 4 instruments working at the same time in the pharynx.
Transoral robotic surgery (TORS) provides the surgeon with a 3D, high-definition view of the operative field from the perspective of being inside the mouth of the patient. The maneuverable scope affords a wide field of vision. The wristed instruments with tremor-filtration, motion-scaling, and 7 degrees of freedom provide precise bimanual tissue manipulation in areas heretofore inaccessible through the mouth, allowing for en-bloc excision and complete visualization of large tumors through the mouth and obviating an external approach and cervical scar. A frequently cited limitation of the robot is the lack of haptic feedback, which many experts feel is compensated for by the superior 3D vision. For the purpose of this article, the use of TORS is examined in the treatment of benign lesions of the pharynx, subdivided into the nasopharynx, oropharynx, and hypopharynx.
Preoperative imaging
Preoperative planning primarily involves using computed tomography (CT) and magnetic resonance imaging (MRI). CT with intravenous contrast provides information on the nasopharynx regarding the status of the skull base, clivus, and pterygoid plates and the relationship of the lesion to the internal carotid artery. In the oropharynx it provides information regarding the location, extent, and vascularity of the lesion in question. In the hypopharynx, CT imaging defines the status of the arytenoids, thyroid cartilage, and proximity to the common carotid artery. MRI provides more soft tissue detail and depth information of the lesions in the nasopharynx, oropharynx, and hypopharynx. In addition, the soft tissue characteristics may assist in the differentiation of a malignant from a benign lesion. Furthermore, CT or MRI may be used in cases whereby navigation is desired, such as described in a combined endoscopic and TORS approach to lesions in the nasopharynx.
Nasopharyngeal lesions
Patient Setup
The patient is placed supine on the operative table and intubated orally. A small endotracheal tube taped to the midline or off to the side affords the most room to work through the mouth. Dental protection with a thermoplastic splint is recommended. The head is kept midline with the neck extended. Muscle relaxation is necessary. A Crowe-Davis or Dingman retractors are most frequently used to open the mouth widely. It is the authors’ practice to administer antibiotics covering mixed pharyngeal flora as well as steroids intraoperatively, which is thought to reduce edema, postoperative pain, nausea, and vomiting. As most procedures last less than 2 hours, there is no need for placement of a urinary catheter unless additional procedures are performed or medical condition warrants.
The table is rotated 180° from anesthesia to maximize exposure to the patient’s head. The robot is docked from either the left or the right side at a 30° angle to the bed. The assistant sits at the head of the bed with a clear view into the mouth as well as to the video cart monitor, which shows the endoscopic view.
Surgical Technique
Nasopharyngeal dissection was initially described by Ozer and Waltonen, in which a Dingman retractor was used for transoral exposure. All 4 robotic arms were placed through the mouth with a 30° scope facing superiorly. The soft palate was incised lateral to midline and separated from the attachments to the hard palate and pharyngeal wall and the opposite soft palate and uvula were retracted with the fourth robot arm, allowing for adequate exposure of the nasopharynx. Similar to the above technique, Wei and Ho described adequate visualization and access to the nasopharynx between the 2 posterior crura of the eustachian tubes with a 0° camera. This technique uses a lateral palatal flap approach whereby an incision is carried from the incisive foramen to the greater palatine foramen contralateral to the tumor ( Fig. 1 ). The incision is carried onto the soft palate toward the superior pole of the tonsil 1 cm medial to the gingiva, which affords better access to the lateral nasopharynx and parapharyngeal space. Care must be taken not to injure the contralateral greater palatine vessels because they are the dependent supply of the palatal flap.
