Commentary on Tailored Fundoplication for GERD With Impedance Planimetry (EndoFLIP™)

Since it was first performed over 100 years ago, a number of techniques have been developed in the pursuit of optimal patient outcomes following anti-reflux surgery (ARS) for gastroesophageal reflux disease (GERD). Most recently, EndoFLIP™ has emerged as a highly effective tool that can measure gastroesophageal junction (GEJ) physiology in real time and has been utilized to predict post-operative outcomes following ARS.^1,2 This is an important new frontier in ARS. Clinicians are now able to improve outcomes for their patients by providing optimal symptomatic control while reducing procedure-related side-effects. In “Tailored Fundoplication for GERD with Impedance Planimetry (EndoFLIP™),” Wu et al ³ describe their experience using intraoperative measurements of the GEJ distensibility index (DI, mm²/mmHg) measured by EndoFLIP™ to alter their choice of fundoplication (Nissen vs Toupet) in patients undergoing ARS. This is a novel first step in creating a methodical technique of obtaining real-time feedback for surgeons and clinicians.

In those patients younger than 70 years-old who had an adequately-sized gastric fundus, Wu et al ³ performed a Nissen fundoplication on patients whose DI was >7 mm²/mmHg after hiatal dissection. In those whose DI after hiatal dissection was ≤7 mm²/mmHg, or in those with a small fundus, a Toupet fundoplication was performed. This approach led to significantly less gas bloat symptoms at 2 years after ARS, significant improvement in reflux-related outcomes, and could be performed with minimal morbidity. ³

The lower esophageal sphincter (LES) at the GEJ is comprised of the paraesophageal ligament, intrinsic semicircular smooth muscle, the extrinsic muscle of the crural diaphragm, and the sling-like fibers of the gastric muscle in the cardia. ⁴ Disruption of any component of the aforementioned will therefor affect LES physiology. To this extent, hiatal hernias, whereby the contribution of the extrinsic muscle of the crural diaphragm is minimized, are known to increase the DI of the GEJ; ARS consistently results in overall decreases of the DI at the GEJ.^1,5

Throughout ARS, crural closure following hiatal dissection has been reported to contribute approximately 80% to the overall change in the DI of the GEJ, whereas the fundoplication itself (both Nissen and Toupet) contributes 20%. ⁵ One must therefore question whether tailoring the choice of fundoplication based on data obtained when the contribution of the crural diaphragm is at its nadir—that is, following hiatal dissection but prior to crural re-approximation—represents the ideal intra-operative time point for surgical decision-making. Rather, DI measurements obtained following crural closure may potentially serve as a better reference points to tailor the choice of fundoplication given the disproportionate contribution of the crural closure to changes in DI. ⁵

Wu et al ³ mainly conclude that incorporating EndoFLIP™ into operative decision-making during ARS may result in less gas bloat at 2 years post-operatively. However, pre-operative gas bloat is likely under-appreciated in patients presenting for ARS, but in our experience is present in up to 20% of patients and may be in excess of 70%.^2,5,6 Unfortunately, the prevalence of pre-operative bloat was not reported by Wu et al, ³ nor was the operative management of these patients fully delineated. Was the algorithm applied to patients with known pre-operative bloat? Did patients who had known gas bloat but a post-hiatal dissection DI >7 mm²/mmHg still undergo a Nissen fundoplication? These omissions make it difficult to properly frame the reported findings. Further, if the gas bloat was directly related to the choice of fundoplication, one may expect to see a difference establishing itself prior to the 2-year mark. A larger proportion of patients at >2-years post-operatively in the non-FLIP group may be contribute to these findings.

The study “Tailored Fundoplication for GERD with Impedance Planimetry (EndoFLIP™)” is clearly a novel and important first step in allowing clinicians to better assess in real-time management algorithms for improving patient outcomes while mitigating side-effects from ARS. ³ It does highlight the importance of creating a standardized protocol on which intra-operative decision-making consistently hinges and represents a major advance in ARS. Due to immediate feedback provided by EndoFLIP™, foregut surgeons performing ARS now have an additional tool—a “smart bougie”—that helps guide their operation. More data is needed to delineate the optimal approach and methods of tailoring surgery. EndoFLIP™ will be an essential component of these advances. Reaching consensus on the optimal intra-operative time and physiologic parameter to base this decision making will come in time.