Gastroesophageal reflux disease (GERD) has a prevalence of 30% in North America (Richter
2018), where patients can present with reflux, heartburn, dysphagia, chest pain, or a
combination of symptoms. Those referred by their primary care physician to a specialist have
often already failed a trial of proton pump inhibitors (PPI), thus warranting further
investigation. Practice guidelines from the American College of Gastroenterologists (Katz
2013) recommend that patients undergo upper endoscopy, followed by esophageal manometry, and
reflux monitoring before any surgical intervention.
While these recommendations are well-founded, patient compliance with these tests remains
low, since esophageal manometry and 24-hour pH testing are generally poorly tolerated,
involving the placement of probes inserted nasogastrically. A qualitative study investigated
patient perceptions of 24-hour pH monitoring and manometry testing (Walamies 2002) and asked
92 patients to describe their experience with manometry. Of the 84 respondents, 52% reported
moderate-severe discomfort. It was shown that many patients are fearful and anxious about
these tests. Some may refuse them due to their invasiveness, especially if having already
undergone endoscopic evaluation. Undergoing surgery with an indeterminate diagnosis or in the
absence of a full motility assessment is contraindicated by current practice guidelines and
devastating consequences could occur. The lack of preoperative investigations could omit a
large subset of potential surgical candidates or even lead to anti-reflux surgery in patients
for the wrong diagnosis.
Once a patient is considered a surgical candidate, operative management aims to reestablish
the anti-reflux barrier by plicating the gastric fundus around the gastroesophageal junction
(GEJ), called fundoplication. Until now, there is no established objective measure to
determine how tight to make the fundoplication. Some surgeons use a bougie to estimate the
diameter of the GEJ (Patterson 2000), while some use an endoscope, and others rely on their
subjective judgement. A fundoplication that is too narrow can cause severe postoperative
dysphagia symptoms, whereas one that is too loose may cause recurrence or worsening of GERD
symptoms. A balance is required.
The EndoFLIP balloon catheter allows users to measure the cross-sectional area (CSA),
diameter, pressure and distensibility index (DI) of the GEJ. This can be done
intraoperatively to obtain objective measures of the tightness of the fundoplication. These
results may then be correlated with post-operative symptoms to determine the optimal CSA and
DI in fundoplication. Previous studies have sought to address this problem but were limited
by their lack of standardized EndoFLIP use (Su 2019). Symptom severity measurements were also
captured too early in the post-operative period before a new baseline was established
(Nwokedi 2020). This proposed study will have a defined EndoFLIP protocol that will be used
to obtain all measurements. In addition, our post-operative readings will be captured no
earlier than four months from the date of surgery. The investigators attempt to establish
objective measurements to guide future operative interventions, thereby improving
postoperative symptoms and overall patient satisfaction.
During the pre-operative workup, most patients with a clinical indication for 24-hour pH
monitoring and manometry testing will undergo an esophagogastroduodenoscopy (EGD). This is
much better tolerated, allowing for the administration of topical anesthetic and intravenous
sedating medications. EndoFLIP readings can be taken at the time of EGD, thereby decreasing
the number of investigations that may prolong preoperative workup. Clinicians may be able to
rely on these readings alone in select patients.
Prior studies investigating the use of this novel technique have compared preoperative and
post-operative CSA and DI values following a wide range of esophagogastric procedures [Attaar
2021, Ichkhanian 2020] and others have established a relationship with patient reported
outcomes [Su 2020, Nwokedi 2020]. Some have compared CSA and DI in patients with and without
achalasia [Carlson 2015]. Others have attempted to identify a correlation between EndoFLIP
readings and anorectal manometry [Zifan 2018, Leroi 2018], and with pyloric manometry [Snape
2016]. One group of investigators [Tucker 2013] attempted to validate EndoFLIP readings with
acid exposure time on pH testing and found no correlation between the two. That study was
limited by its small sample size and the retrospective nature of the data, resulting in
uncontrolled confounding. A true correlation between EndoFLIP measurements with 24-hour pH
monitoring and esophageal manometry has yet to be identified.
To summarise, a knowledge of the intra-operative EndoFLIP measurements that correlate with
acceptable post-operative symptom severity scores will be useful information for surgeons
performing a fundoplication (there currently is no gold standard for fundoplication
creation). Secondly, if pre-operative EndoFLIP measurements correlate well with pre-operative
24-hr pH studies and manometry testing, then there is a potential for EndoFLIP to replace
these invasive, uncomfortable, and poorly tolerated tests. This may result in increased
patient compliance and reduced costs of pre-operative testing.