The da Vinci cart is positioned in the contralateral side, while the robotic arms extend over the patient. The three arms and the camera are inserted through the axillary incision and along the working space (ProGrasp forceps, harmonic shears, and Maryland dissector). The correct alignment of the robotic arms within the tunnel is crucial to avoid collision of the robotic arms inside the working space, during the console time. The recommended alignment of the robotic arms is with the forceps used for retraction at the top of the working space, the Harmonic scalpel (Harmonic ACE^® curved shears) on the inferior cephalad side, the dissector on the inferior caudal, and the camera in the middle inferior of the surgical field. The assistant may further retract the strap muscles using the suction catheter.

The thyroidectomy is performed in the classical order: first, dissecting the superior pole off the cricothyroid muscle, using the harmonic shears, and safely transecting the superior thyroid vessels close to the gland as to avoid external branch of SLN injury; second, the thyroid lobe is retracted medially in order to expose the parathyroid glands and the recurrent laryngeal nerve (RLN). After ligating the inferior thyroid vessels and identifying the trachea, further mobilization is achieved, and further medial dissection is carried out while carefully preserving the RLN. The lobe is carefully dissected from Berry’s ligament and extracted through the axillary incision. Saline irrigations may assist in preventing thermal injury to the RLN from the harmonic shears. A clip demonstrating the robotic hemithyroidectomy is attached.

A total thyroidectomy is performed via the same axillary incision used for the ipsilateral lobe. The decision regarding which lobe to dissect first should not differ from the cervical approach where the surgeon would usually favor resecting the larger lobe or nodule side first. The axillary incision should be performed ipsilateral to that lobe, and the resection should be carried out in the same fashion detailed above, before attempting to resect the contralateral lobe. After the extraction of the ipsilateral lobe, the assistant should retract the trachea downward, while the superior pole of the contralateral lobe is retracted upward using the ProGrasp forceps. The deep aspect of the lobe is then dissected away from the trachea using the harmonic shears. It should be noted that the contralateral RLN is not easily visible as is the ipsilateral one so care must be taken to avoid injury.

Some surgeons advocate removing the thyroid with an endo-bag as to avoid any tissue spillage. Lastly, a drain is placed in the thyroid bed [12, 15].

The most considerable advantage of RATS over conventional cervical thyroidectomy is that it avoids any cervical incision. This cosmetic aspect makes RATS appealing especially to young female patients, which is the majority of the patient population, and those with a tendency toward keloid or hypertrophic scar formation. An example of an axillary scar can be seen in Fig. 10.3.

The RATS has some major technical advantages. First, the robotic camera provides three-dimensional high-resolution visualization, which enables an easier identification of the RLN and parathyroid glands compared to the cervical approach; second, the robotic arms eliminate the natural surgeon tremor; and, third, it provides a wider range of motion through the robot’s EndoWrist and the articulations of the arms. In addition, the improved visualization and surgical ergonomics have been reported to reduce musculoskeletal discomfort to the surgeon compared with open or endoscopic surgery [7].

Lastly, with regard to patients’ quality of life, RATS was found to yield better patient outcomes, including reduced pain and increased cosmetic satisfaction, as well as lower rates of paresthesia over the neck, postoperative voice change, and swallowing discomfort [16, 17].

This relative new approach to the thyroid gland, in terms of the surrounding anatomy and the loss of tactile sensation, may expose the patient to potential new complications such as tracheal, esophageal, or brachial plexus injury. Very few studies accounted for such complications, with minimal attention to the conversion rate to open thyroidectomy. Due to the ipsilateral arm position, there is a risk of brachial plexus neuropathy. This risk can be reduced by placing the arm in a flexed overhead 90° position, thereby reducing the chance of stretching the nerves. Care must be taken to avoid local pressure from the robotic arm. Intraoperative neurophysiological monitoring of the ulnar, radial, and median nerves may further reduce the possibility of brachial plexus injury, by identification of any impending damage to these nerves and enabling the patient to be repositioned as needed [18]. Intraoperative monitoring has shown to decrease rates of hypoesthesia and pain and improve shoulder movement, as well as higher quality of life, in the early postoperative period [19]. Despite the benefits of intraoperative monitoring, it is not obligatory in RATS.

Another disadvantage of RATS is the longer operative time mainly due to the extra time needed for the creation of the working space and the robot docking. In different studies, it is assessed as 1.5–3 times compared to the cervical approach. However, several studies have examined the learning curves of the RT and have shown that increased experience led to decreased total operative time [1]. RATS involves a relatively challenging learning curve, compared to the conventional approach. However, it has been demonstrated that RT required 35–40 procedures, much lower compared to the endoscopic approach [7]. Park et al. examined the learning curves of surgeons with little or no experience, performing transaxillary RT on 125 patients. They showed excellent results compared to those in a larger series of more experienced surgeons and, specifically, that the operation times gradually decreased, reaching a plateau after 20 procedures [20]. Another disadvantage of RATS is the limitation in the body habitus and BMI. With RATS, the working space dissection is relatively more challenging in obese patients (BMI >30). However, it has been demonstrated, and per the authors’ experience, that in skilled hands, the body habitus limitation is irrelevant [21, 22].

In terms of economic considerations, RT is a more expensive procedure compared to open thyroidectomy, primarily due to the cost of the equipment (da Vinci robot itself and periodic maintenance of the robotic arms), staff training, and longer operative time. However, RT actually eliminates the need for an additional surgical assistant, and, combined with the potentially shorter hospital stay and the expected decrease in the maintenance cost of the robot, this may lower the costs of the procedure.

RATS is being practiced mainly in South Korea and Asia and, to a smaller extent, in Europe and North America. With the rising popularity of RT, several meta-analyses were conducted in order to examine both the surgical and oncological safety of RT compared to conventional and endoscopic approaches.

In 2015, Kandil et al. summarized 18 studies, including 4878 patients, and concluded that RT was associated with longer total operative time (mean difference 43 min) and had similar risks of total postoperative complications and similar oncological results [23].

Another meta-analysis published in 2014 by Jackson et al. [1] summarized a total of nine studies with 2881 patients, 1122 of whom underwent RT. They conclude that RT is as effective as endoscopic and open thyroidectomy, with equivalent postoperative results, shorter hospitalization, and higher patient satisfaction. Several other meta-analyses with overall 1000–3000 patients demonstrated similar results, in addition to lower blood loss and lower level of swallowing impairment [16, 24–26].

Lee et al. have also published their experience with 2014 patients who underwent RATS, with a low complication rate of 1% for major complications (e.g., permanent RLN or brachial injury, conversion to open thyroidectomy) and 19% for minor ones (transient hypocalcemia, seroma, etc.). Interestingly, this group also found that in terms of the surgeon’s musculoskeletal ergonomic parameters, RATS resulted in less neck and back discomfort than did the endoscopic or open thyroidectomy [7].

One of the relative contraindications of RATS is Graves’ disease, due to the usually large-volume thyroid glands and hypervascularity. However, some surgeons have already reported their successful experience with Graves’ patients showing similar complication rates, blood loss, and hospital stay [27, 28]. The largest European experience from Paris, France, with over 350 robotic thyroidectomies and neck dissections, is also very promising with low complication rates. Interestingly, almost 60% of their RT involved large-volume thyroid glands (over 20 mL) [29]. It should be noted that all patients received potassium iodide preoperatively.

In skillful hands, RATS can be feasible and safe for patients with large-volume thyroid glands such as Graves’ and MNG patients.