The role of mucosal impedance in the assessment of the reflux barrier after Nissen fundoplication.

BACKGROUND

Mucosal impedance (MI) is a novel diagnostic tool that quantifies esophageal mucosal integrity by measuring tissue conductivity. Previous studies have demonstrated that healthy individuals exhibit high, stable MI values throughout the esophagus and that those with gastroesophageal reflux disease (GERD) exhibit low distal MI values and a steep axial gradient. The role of MI in the postoperative setting has not been evaluated, and it is unknown whether antireflux surgery (ARS) restores mucosal integrity to normal levels. This study aimed to determine whether MI differentiates between intact and failed Nissen fundoplication and objectively assesses reflux barrier function after ARS.

METHODS

Patients who underwent Nissen fundoplication and had either intact or failed (slipped, disrupted, or herniated) fundoplication on endoscopy at ≥1 year were offered MI testing. In addition, a non-GERD control group (n = 10) with no previous foregut surgery and normal endoscopy and pH monitoring underwent MI testing. MI was measured at 1-cm intervals along the distal esophagus. Axial MI patterns were compared between the groups.

RESULTS

The study included 25 post fundoplication patients (60% female, mean age of 61.3 ± 13.7 years, and mean body mass index of 28.2 ± 4.7 kg/m), 11 with intact fundoplication and 14 with anatomical failure. Patients with intact fundoplication had significantly higher MI values at 1 (P =.0326), 2 (P =.005), 3 (P <.05), and 5 (P =.018) cm above the squamocolumnar junction (SCJ). All MI values and patterns in patients with intact fundoplication were comparable with those of non-GERD controls (P >.05). Patients with failed fundoplication had a steeper axial MI gradient than those with intact fundoplication (251 vs 23 Ω/cm, respectively; P <.05). In addition, the distal MI value was significantly lower in patients with failed fundoplication than in those with intact fundoplication (2706 vs 4921 Ω, respectively; P <.05).

CONCLUSION

MI demonstrates that an intact Nissen fundoplication restores mucosal integrity to levels comparable to those of individuals without GERD. Failed fundoplications exhibit persistent GERD-like MI patterns. Therefore, MI provides an objective physiologic marker of surgical success and may aid in postoperative management.