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Page 6 of 16 Hasson et al. Mini-invasive Surg 2020;4:46 I http://dx.doi.org/10.20517/2574-1225.2020.10

robotic McKeown three-field esophagectomy 1 year later. It included both the thoracic and abdominal phases
[41]
[39]
followed by cervical anastomosis described for the MIE with differing port placements . Dunn et al.
were the first to describe their longer-term outcomes reporting on their 3-year experience performing
THE, and others have more recently described the robotic IL esophagectomy. Today, similar to MIE, there
are several additional combinations of thoracic and abdominal phases including VATS/mini-thoracotomy/
thoracotomy and laparoscopy/mini-laparotomy/handport or traditional laparotomy (also known as the
hybrid robotic esophagectomy, Table 1, Items 10-13).

The use of computer-assisted technology (also known as robotics) provides several advantages including
10-fold magnification and three-dimensional visualization [27,38,42] . The endowrist provides seven degrees of
freedom and works to simulate normal wrist movements, while it employs a motion filter up to 60 Hz that
works to reduce tremor [38,42] . Most importantly, for most uses, the fulcrum of the instrument lies inside the
[42]
body instead resting on the body wall, which helps to decrease postoperative pain . Although the depth of
the benefits cannot be denied, there are some important disadvantages. Access to robotic platforms can be
limited depending on the resources of the host institution. Given the expense attached to their use, specific
departments must often be able to establish need to justify the cost, which can prove difficult for smaller
centers. Surgeon comfort can be a challenging hurdle to overcome given unfamiliarity with the use of this
platform in the aging surgeon population, and lack of training in new graduates. Most importantly, the lack
of haptic feedback makes the use of robotic surgery challenging once it is incorporated in one’s practice,
which can increase the rate of devastating and life-threatening complications in novice users.

Learning curve of minimally invasive and robotic esophagectomy
As stated above, performing minimally invasive or robotic-assisted procedures is technically complex
[43]
and they have significant learning curves. Decker et al. specifically reviewed the relationship between
surgical experience and minimally invasive esophagectomy outcomes and found centers performing 50 or
[27]
more cases had lower morbidity and mortality rates than centers with less expertise . They also had more
experience performing more complex lymph node dissections. Early estimates of cases needed to obtain
proficiency resided around 35-40 operations, with 25 cases used as a benchmark required for competent
performance of a lymphadenectomy [27,43] . Today, the precise number of procedures needed to determine if
[44]
a surgeon is proficient has still not been definitely established, as Claassen et al. described in their recent
review. However, parameters such as estimated blood loss, operative time, the number of lymph nodes
retrieved, anastomotic leak rate, duration of hospital stay, and overall complication and mortality rates can
serve as benchmarks.

Regarding robotic esophagectomy, the reports have been somewhat varied and recent articles estimate
the optimal number to range between 20-80 cases depending on the outcome parameter surveyed [45-47] .
[45]
Park et al. retrospectively reviewed 33 patients divided into two groups, the first 20 cases and the
subsequent 13. While the operative time, robotic console time, lymph node dissections, and blood loss
were similar between the two groups, the incidence of vocal cord palsy was significantly lower in Group
[45]
[46]
2 . Zhang et al. demonstrated that 26 cases were required to gain proficiency of robotic-assisted
McKeown esophagectomy for surgeons experienced in open and thoraco-laparoscopic esophagectomy.
More specifically related to the learning curve, they estimated robotic-assisted esophagus dissection would
[46]
require operations on 26 patients with stomach mobilization requiring 14 operations . The bedside
assistant would need at least nine cases to achieve an optimal technical level of thoracic docking, and 16
[47]
[46]
cases for abdominal docking . Park et al. had a more varied range, demonstrating that the number of
harvested lymph nodes increased from 25 before 30 cases to 45 after, and vocal cord palsy decreased from
36% before 60 cases to 17% after. Total operative time decreased from 496 to 431 min, rate of anastomotic
[47]
leakage decreased from 15% to 2%, and the length of stay decreased from 24 to 14 days after 80 cases .
Clearly, the use of robotics adds a level of complexity to the case and requires many hours of training and
multiple cases for a surgeon to perfect their technique to decrease the risk to the patient.