INTRAOPERATIVE ASSESSMENT OF ESOPHAGOGASTRIC JUNCTION DISTENSIBILITY DURING HELLER MYOTOMY WITH ENDOLUMINAL FUNCTIONAL LUMEN IMAGING PROBE DEVICE (EndoFLIP)

Reece K DeHaan, BA, Matthew J Frelich, MS, Matthew I Goldblatt, MD, Andrew S Kastenmeier, MD, Jon C Gould, MD. Medical College of Wisconsin

BACKGROUND: We sought to characterize the changes in EGJ distensibility at various intervals during Heller Myotomy with Dor fundoplication for the treatment of Achalasia. Intraoperative measurements were correlated with postoperative outcomes. Achalasia is a relatively rare esophageal motility disorder characterized by impaired relaxation of the lower esophageal sphincter, poor bolus clearance with swallowing and decreased distensibility in untreated patients.

METHODS AND PROCEDURES: This study is a retrospective review of prospectively maintained data. All patients underwent Heller myotomy for achalasia over a 10-month period. A novel functional luminal imaging probe, EndoFLIP®, utilizing impedance planimetry and a bag that can be filled with varying amounts of saline solution was used for intraoperative measurements. Minimum esophageal diameter (Dmin), cross-sectional areas (CSA) and EGJ distensibility index (DI) were measured at 30mL and 40mL distension volumes prior to abdominal insufflation, post myotomy, and after the completion of a Dor fundoplication using EndoFLIP. DI (CSA/Pressure) is defined as the narrowest CSA and the corresponding pressure expressed in mm2/mmHg. Symptomatic outcomes were assessed up to two months post-op using the validated Achalasia Severity Questionnaire (ASQ) and Eckhardt Score. A Wilcoxon-Signed rank test was performed to assess significance.

RESULTS: A total of 10 patients underwent Heller myotomy during the study interval. Mean age was 56±19 years. Mean BMI was 30.5±9.8 kg/m2. One patient underwent a takedown of a previous fundoplication followed by reoperative Heller Myotomy and one patient had a hiatal hernia. All measures except intrabag pressure increased significantly from pre-insufflation to post myotomy for both 30 and 40 mL distension volumes (Table). All measures except intrabag preassure and the 30 mL distensibility index also increased significantly from pre-insufflation to post-fundoplication for both volumes (Table). Mean ASQ score improved from 74.8 during the preoperative visit to 28.9 at 2 months postop while mean Eckhardt score improved from 8.8 to 3.0.

Measurement Dmin (mm) CSA (mm2) Intrabag Pressure (mmHg) DI (mm2/mmHg)
Pre-insufflation (30 mL) 5.8±1.2 26.6±12.0 24.3±14.8 1.43±0.90
Post myotomy (30 mL)

10.4±1.5*

88.1±24.8* 25.7±7.9 3.58±1.22*
Post fundoplication (30 mL)

7.2±1.6*

42.6±18.9* 24.5±8.0 1.71±0.44
Pre-insufflation (40 mL)

7.9±3.0

44.4±21.3 33.3±10.2 1.33±0.51
Post myotomy (40 mL) 13.3±1.9* 126.3±59.1* 29.5±8.6 4.97±1.48*
Post fundoplication (40 mL) 9.8±1.8* 78.4±28.1* 30.8±7.0 2.49±0.51*

Table: EndoFLIP® variables reported as mean (range). Significant differences from pre-insufflation are noted (*=p≤0.05).

CONCLUSIONS: Minimum esophageal diameter and EGJ distensibility increase significantly with Heller myotomy for achalasia. Symptom scores improved dramatically in all patients. Further study is necessary to determine if intraoperative EGJ distensibility testing can be used to identify patients at risk for inferior symptomatic outcomes following surgery and ultimately to allow surgeons to tailor the extent of the myotomy on an individual basis guided by EGJ distensibility metrics.

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