Abstract
Transoral robotic surgery (TORS) allows resection of otherwise inaccessible pathology. It generates unique challenges to the airway management of the patient due to the shared location of the anaesthetist and the surgeon’s equipment. A close cooperation between the anaesthetic and surgical team is required, for the safe handling of the airway. The anaesthetist needs to be able to employ a variety of airway manoeuvres in order to ensure the airway patency throughout the perioperative and post-operative period. The airway of the TORS patient is characterised by its dynamic nature, as it changes due to the surgery, swelling and bleeding.
Introduction
Transoral robotic surgery (TORS) is becoming increasingly widespread. The use of a surgical robot allows access to surgical sites in the oropharynx, base of the tongue, laryngeal inlet and soft palate that would otherwise be inaccessible or require a mandibular split to obtain access. The surgery is performed through a rigid gag, and the arms of the surgical robot are controlled by the surgeon sitting at a remote console. The surgeon controls the robotic arms via hand controls and has a three-dimensional view of the surgical site, via optical lenses at the control station.
The robotic arms are manually guided to optimal positions and their relative positions are logged, the so-called docking procedure. Further movement of the robotic arms is done by the surgeon via the remote console. To remove the robotic arms from the oral cavity requires undocking of the robot and manually guided removal by the assistant. Renewed surgical access requires that the docking procedure is repeated. An assistant facilitates surgical access with retractors and camera positioning.
The surgeon can employ multiple surgical tools on the robotic arms, and the computer filters out involuntary motions of the surgeon’s hands, thus providing a steady movement of the tools. There is, however, no tactile feedback, and the surgeon is thus limited to the inputs he or she can see. In order to raise team situation awareness, the camera view can be broadcast to one or more screens in the operating theatre.
This kind of surgery poses unique challenges as the multiple surgical instruments share the same space as the airway placed by the anaesthetic team.
Preparation
Airway management of the TORS patient poses some of the same challenges as other patients with airway pathology. A thorough preoperative assessment of the airway, including a preoperative nasendoscopy, should be standard, and will identify most difficult airways prior to anaesthesia. No patient should be anaesthetised for TORS without having their cricothyroid membrane assessed. In case of difficulty palpating it, ultrasound assessment should be used to mark it prior to induction of anaesthesia (see Chapter 7).
The choice of airway route (nasal, oral or front of neck) should be discussed with the surgeon, as their surgical access can be affected by the anaesthetist’s choice of airway route.
Choice of Airway Equipment
Due to the nature of the surgery, only tracheal intubation or tracheostomy are valid airway solutions during the surgery.
Choosing the right tracheal tube for TORS is an act of balancing the requirements of the surgeon to the safety and comfort of the patient. The tube should be resistant to compression from the robotic arms, thus requiring a wire-reinforced tube. These tubes resist compression well, but if compressed above their resistance threshold they will buckle and then remain compressed.
If the surgeon uses laser during the procedure, the tube should also be laser resistant. Otherwise a plan for draping and protecting the tube should be formulated in close cooperation with the surgeon. Depending on the proximity of the surgical field to the tube, and the use of monopolar cautery equipment, there is also a risk of heat transfer to the tube, thus requiring the tube to be heat resistant.
If the patient is orally intubated, a floppy tube may require stitches to keep it out of the surgical field, introducing the risk of retained stitches at extubation.
A wire-reinforced, laser- and heat-resistant tube will often be able to stay out of the surgical field, but may cause bleeding and has an increased risk of submucosal placement, when introduced through the nose. Standard wire-reinforced tubes are gentler on the nasal cavity, but often lack the proper length to be placed nasally without risking pressure sores at the nares. Guide the nasal tube through the nose by threading it over a soft suction catheter to minimise the risk of submucosal placement.
If the surgery is near the laryngeal inlet, a double cuffed tube may be preferable, due to the risk of damage to the cuff (Figure 33.1).
