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Mechanisms of acid, weakly acidic and gas reflux after anti-reflux surgery
  1. Albert J Bredenoord (a.bredenoord{at}
  1. St Antonius Hospital, Netherlands
    1. Werner A Draaisma
    1. University Medical Center Utrecht, Netherlands
      1. Bas L.A.M. Weusten (b.weusten{at}
      1. St Antonius Hospital, Netherlands
        1. Hein G Gooszen
        1. University Medical Center Utrecht, Netherlands
          1. André J.P.M. Smout (a.smout{at}
          1. University Medical Center Utrecht, Netherlands


            Background/Aim Whereas it is well documented that fundoplication reduces acid reflux, the effects of the procedure on non-acid and gas reflux and the mechanisms through which this is achieved have not been fully elucidated.

            Methods: In 14 patients, reflux was measured with impedance-pH monitoring during a postprandial 90-min stationary recording period before and 3 months after fundoplication. Concomitantly, the occurrence of TLOSRs and morphology of the oesophagogastric junction were studied with high-resolution manometry. This was followed by 24-hr ambulatory impedance-pH monitoring.

            Results: Before fundoplication two separate high-pressure zones (hernia profile) were detected during 24.9 % of total time, during which there was a large increase in reflux rate. After fundoplication the hernia profile did not occur. Fundoplication decreased number of TLOSRs (from 10.5±1.2 to 4.5±0.7, p<0.01) and also percentage of TLOSRs associated with acidic or weakly acidic reflux (from 72.7 to 4.1 %, p<0.01). Nadir pressure during TLOSRs increased after surgery (from 0 (0-0) to 1.0 (1-2) kPa, p<0.05). In the ambulatory study, there was a large decrease in prevalence of both acid (-96%, from 47.0±5.9 to 1.8±0.5, p<0.01) and weakly acidic reflux (-92%, from 25.0±9.7 to 2.3±0.9, p<0.01). The decrease in gas reflux was less pronounced (-53%, from 24.2±4.9 to 11.3±3.0, p<0.01).

            Conclusions: Fundoplication greatly reduces both acid and weakly acidic liquid reflux, gas reflux is reduced to a lesser extent. Three mechanisms play a role: 1. abolition of the double high-pressure zone profile (hiatal hernia), 2. reduced incidence of TLOSRs and 3. decreased percentage of TLOSRs associated with reflux.

            • fundoplication
            • gastro-oesophageal reflux
            • impedance
            • oesophageal
            • transient lower oesophageal sphincter relaxation

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