Characterisation of post-fundoplication gastric dysfunction using Gastric Alimetry

Background Adverse gastric symptoms persist in up to 20% of fundoplication surgeries completed for gastroesophageal reflux disease, causing significant morbidity, and driving the need for revisional procedures. Non-invasive techniques to assess the mechanisms of persistent postoperative symptoms are lacking. We aimed to investigate gastric myoelectrical abnormalities and symptoms in patients after fundoplication using a novel non-invasive body surface gastric mapping (BSGM) device. Methods Patients with previous fundoplication surgery and ongoing significant gastroduodenal symptoms, and matched controls were included. BSGM using Gastric Alimetry (Alimetry, New Zealand) was employed, consisting of a high resolution 64-channel array, validated symptom-logging App, and wearable reader. Results 16 patients with significant chronic symptoms post-fundoplication were recruited, with 16 matched controls. Overall, 6/16 (37.5%) patients showed significant spectral abnormalities defined by unstable gastric myoelectrical activity (n = 2), abnormally high gastric frequencies (n = 3) or high gastric amplitudes (n = 1). Those with spectral abnormalities had higher Patient Assessment of Upper Gastrointestinal Disorders-Symptom Severity Index scores (3.2 [2.8 to 3.6] vs 2.3 [2.2 to 2.8]; p =0.024). 7/16 patients (43.8%) had Gastric Alimetry tests suggestive of gut-brain axis contributions, and without myoelectrical dysfunction. Increasing Principal Gastric Frequency deviation, and decreasing Rhythm Index were associated with symptom severity (r>0.40, p<0.05). Conclusion A significant number of patients with persistent post-fundoplication symptoms display abnormal gastric function on Gastric Alimetry testing, which correlates with symptom severity. These findings advance the pathophysiological understanding of post-fundoplication disorders which may inform diagnosis and patient selection for medical therapy and revisional surgery. ### Competing Interest Statement Professor Greg O'Grady, holds grants and intellectual property in the field of gastrointestinal electrophysiology and is a co-founder and Director in University spin-out companies: The Insides Company Ltd and Alimetry Ltd. Dr Gharibans holds grants and intellectual property in the field of gastrointestinal electrophysiology and is a co-founder and Director of Alimetry Ltd. Dr Calder, Dr Schamberg, and Dr Daker, are members of Alimetry Ltd. The remaining authors have no conflicts of interest to declare. ### Funding Statement This project was supported by the Health Research Council of New Zealand, the NIH (R56 DK126935) and the John Mitchell Crouch Fellowship from the Royal Australasian College of Surgeons. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethical approval for reporting was obtained from the Auckland Health Ethics Research Ethics Committee and Western Sydney Human Research Ethics Committee (ref: AH1130, H15157). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors