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Page 4 of 8 Creden et al. Mini-invasive Surg 2024;8:21 https://dx.doi.org/10.20517/2574-1225.2024.19

COMMON TECHNIQUES FOR PYLORIC DRAINAGE DURING ROBOTIC-ASSISTED
MINIMALLY INVASIVE ESOPHAGECTOMY
Robotic-assisted laparoscopic pyloroplasty
When performed robotically, a Heineke-Mikulicz pyloroplasty should follow the same principles as when
[23]
the operation is performed via an open approach . After placing stay sutures through the pyloric ring
superiorly and inferiorly, a longitudinal incision is made to expose and divide the pyloric ring completely;
we prefer to use monopolar cautery. Though running closures have been described, we prefer to use an
interrupted 2-0 braided polyester suture, taking care to take separate bites of the serosa and mucosa on the
gastric side of the pylorus. We cover the completed closure with a loose tongue of omentum. Whereas
pyloric drainage has been touted by some to have greater technical difficulty with a conventional
[24]
laparoscopic approach , robotic assistance arguably re-simplifies surgical pyloromyotomy and
pyloroplasty to a degree of technical complexity comparable to the traditional open approach; indeed, the
additional degrees of motion and dexterity afforded by robotic instrumentation decrease operative times for
[25]
a surgical pyloroplasty as compared with those of traditional laparoscopy . The primary limitations of
robotic pyloroplasty include the limited availability of robotic surgical systems in some hospitals and the
cost of the platform and disposable equipment.

Pyloric chemodenervation
Chemodenervation, a temporary method of pyloric drainage, is performed by injecting a small aliquot of
onabotulinum toxin into the subserosal space of the pylorus. The most frequently described dose and
technique is 100 units of toxin diluted in 5cc saline injected into each quadrant of the pylorus,
approximately 20-25 units per quadrant. This is accomplished via either an external approach (i.e.,
intraoperatively, using a 22G spinal needle) or an endoscopic approach (e.g., with a 26G injection needle).
The toxin facilitates pyloric drainage by decreasing pyloric smooth muscle contractility both directly and via
inhibition of acetylcholine release at the neuromuscular junction , and its pharmacologic duration is
[26]
approximately 90 to 120 days. Cerfolio et al. reported favorable results with this technique: patients who
underwent chemodenervation at the time of esophagectomy experienced lower rates of radiographic
delayed gastric emptying (59%, vs. rates surpassing 90% for patients who underwent surgical pyloric
drainage or no intervention) . Importantly, patients who underwent pyloric chemodenervation had lower
[2]
rates of biliary reflux symptoms (6%) than those treated with pyloroplasty, which carries a rate of bile reflux
up to 20% to 38%.

A recently published large single-center retrospective analysis by Saeed et al. demonstrated the overall safety
and efficacy of chemodenervation, with several important caveats . Patients who underwent
[27]
chemodenervation at the time of esophagectomy had similar rates of anastomotic leak (approximately 17%-
19%) as those who underwent surgical pyloric drainage (pyloroplasty or pyloromyotomy). While the
chemodenervation group had a shorter length of hospital stay (9.8 vs. 12.1 days), this came at the expense of
a greater rate of delayed gastric emptying (15.9% vs. 9.3%). However, the authors note that this effect is
largely driven by a low rate of delayed gastric emptying among the subset of surgical drainage patients who
specifically underwent pyloroplasty as opposed to pyloromyotomy. Chemodenervation was also associated
with a lower rate of bile reflux (0.4% vs. 2.8%) and postoperative weight loss (9.8 vs. 11.4 kg after six months)
than pyloroplasty. Crucially, the chemodenervation group was more likely to have undergone
esophagectomy via a fully robotic-assisted Ivor Lewis approach, whereas the surgical pyloric drainage group
was more likely to have undergone a hybrid laparotomy/robotic-assisted thoracoscopic approach.

Endoscopic pyloromyotomy
Gastric peroral endoscopic myotomy (G-POEM) [also known as per oral pyloromyotomy (POP)] was first
described as a novel therapeutic technique for refractory gastroparesis, but has since garnered attention as a