Hyperspectral Imaging (HSI) in Acute Mesenteric Ischemia to Detect Intestinal Perfusion Deficits.

BACKGROUND: Acute mesenteric ischemia is a life-threatening acute condition, which requires an interdisciplinary approach, including vascular recanalization and surgical treatment. Visual evaluation of intestinal perfusion might be misleading, and therefore, additional tools are necessary to reliably be able to resect the ischemic intestine. Hyperspectral imaging (HSI) has been shown to be feasible and safe for real-time assessment of tissue perfusion in visceral surgery but has never been used in cases of acute mesenteric ischemia. Therefore, we applied HSI in acute mesenteric ischemia to evaluate it for potential aid in the objectively discriminating ischemic and well-perfused intestine during explorative laparotomy. METHODS: We recorded HSI measurements in 11 cases of acute mesenteric ischemia during explorative laparotomy. We evaluated the recorded images for macroscopic visual perfusion quality and divided it into three groups. Of those three groups, we calculated and compared the HSI indexes of tissue saturation, near-infrared perfusion index, organ hemoglobin index, and tissue water index, as well as the reflectance spectra. RESULTS: We found significant differences in tissue saturation (0.7% versus 0.45%; P = 0.002) and near-infrared perfusion index (0.58 versus 0.23; P < 0.001) in poorly perfused intestinal segments compared with the viable intestine. Furthermore, we could detect an increasing peak at 630 nm of the reflectance spectra in less viable tissues, indicating a maximum in necrotic tissues. We attributed this peak to an increase in met-hemoglobin content in necrotic tissues, which is supported by the increase in the HSI organ hemoglobin index. CONCLUSIONS: HSI is able to discriminate tissue perfusion in acute mesenteric ischemia reliably and therefore might be helpful for resection. In addition, HSI gives information on tissue viability via reflectance spectra.

Before and after Esophageal Surgery: Which Information Is Needed from the Functional Laboratory?

BACKGROUND: Indications for benign esophageal surgery and postoperative follow-up need to be highly elaborated with differentiated and structured algorithms, based on objective functional workup in the esophageal laboratory. Functional outcome is of utmost interest and has to be driven by the need for comprehensive but purposeful diagnostic methods. METHODS: Preoperative diagnostic workup procedures by the functional laboratory include 24-h pH-monitoring, impedance testing, and high-resolution manometry (HRM) - in addition to upper gastrointestinal endoscopy and barium swallow/timed barium esophagogram. RESULTS: The most frequent indications for benign esophageal surgery are gastroesophageal reflux disease and achalasia; quite rare indications are esophageal diverticula and benign tumors. Esophageal motility testing in addition to 24-h pH-monitoring is crucial before antireflux surgery (ARS) in order to rule out ineffective esophageal motility and to tailor the wrap. With respect to achalasia surgery, the exact type of achalasia (I-III) has to be labeled according to the Chicago classification, and other motility disorders have to be excluded. The postoperative functional evaluation in the early phase (6 months) after either ARS or Heller's myotomy serves as the new baseline motility testing in case of later occurring disturbances in the follow-up. CONCLUSION: A complete and proper preoperative esophageal function assessment is crucial in order to rule out a primary motility disorder and to avoid postoperative functional complications.