Initial Assessment of Mucosal Capture and Leak Pressure After Gastrointestinal Stapling in a Porcine Model.

BACKGROUND: Anastomotic leak is a leading cause of morbidity and mortality in gastrointestinal surgery. The serosal aspect of staple lines is commonly observed for integrity, but the mucosal surface and state of mucosa after firing is less often inspected. We sought to assess the degree of mucosal capture when using stapling devices and determine whether incomplete capture influences staple line integrity. METHODS: Porcine ileum was transected in vivo and staple lines were collected and rated for degree of mucosal capture on a 5-point scale from 1 (mucosa mainly captured on both sides) to 5 (majority of mucosa not captured). Mucosal capture was also assessed in ex vivo staple lines, and fluid leakage pressure and location of first leak was assessed. Stapling devices studied were Echelon Flex GST with 60-mm blue (GST60B) and green (GST60G) cartridges, and Medtronic EndoGIA Universal with Tri-Staple Technology™ with 60 mm medium (EGIA60AMT) reloads (purple). RESULTS: GST60B and GST60G staple lines produced significantly better mucosal capture scores than the EGIA60AMT staple lines (p < 0.001, in all tests). Compared to EGIA60AMT, leak pressures were 39% higher for GST60B (p < 0.001) and 23% higher for GST60G (p = 0.022). Initial staple line leak site was associated with incomplete mucosal capture 78% of the time. CONCLUSIONS: There are differences in degree of mucosal capture between commercial staplers, and the devices that produce better mucosal capture had significantly higher leak pressures. Further research is needed to determine the significance of these findings on staple line healing throughout the postoperative period.

Gastric plication: preclinical study of durability of serosa-to-serosa apposition.

BACKGROUND: Vertical gastric plication is a novel surgical approach for reducing the stomach capacity. Anterior surface plication and greater curvature plication are variations of vertical gastric plication that reduce the gastric capacity through infolding of the anterior surface or greater curvature of the stomach, respectively. These approaches have been tested, with positive results in a small number of preclinical and clinical trials. A key step toward greater investigation of vertical gastric plication as a viable bariatric procedure would be confirmation that the apposed serosal tissues can be securely and durably bonded. We compared the short-term durability of gastric plications and serosal bonds using a variety of fastening devices and techniques in a university hospital and private company setting. METHODS: A total of 30 anterior surface plication and 8 greater curvature plication procedures were performed using an open or a laparoscopic surgical technique in 38 hound dogs. The fastening devices used were T-tags, buttressed T-tags, 2 types of suture, and 4 types of staple-based fasteners. The density of the fastening devices was varied among the dogs. With 3 exceptions (2 in keeping with the study design and 1 due to complications), the dogs were followed up for 8 weeks. Histologic examinations and tensile testing were performed postmortem. RESULTS: All fastening devices created durable plication folds, except for 1 technique. The only technique that did not produce durable serosa-to-serosa adhesions was a staple/suture combination. Intentional abrasion of the apposed sites had no demonstrable effect on the bonds between the tissues in any group. Increasing the fastener density and number of rows increased the adhesions within the folds. CONCLUSION: Our findings have confirmed the short-term durability and development of dense fibrous appositions of the serosal folds for fastening approaches that create fixed serosal apposition. Additional studies are needed to identify the optimal fastening modality for anterior surface plication, greater curvature plication, and, ultimately, clinical applications of this procedure.

Sensitization to masked tones following notched-noise correlates with estimates of cochlear function using distortion product otoacoustic emissions.

Neuronal gain adaptation has been proposed as the underlying mechanism leading to the perception of phantom sounds such as Zwicker tones and tinnitus. In this gain-adaptation theory, cochlear compression plays a significant role with weaker compression leading to stronger phantom percepts. The specific aim of this study was to find a link between the strength of neuronal gain adaptation and cochlear compression. Compression was assessed using distortion product otoacoustic emissions (DPOAEs). Gain adaptation is hypothesized to manifest itself in the sensitization observed for the detection of masked tones when preceded by notched noise. Perceptual thresholds for pure tones in notched noise were measured at multiple frequencies following various priming signals. The observed sensitization was larger than expected from the combined effect of the various maskers. However, there was no link between sensitization and compression. Instead, across subjects, stronger sensitization correlated with stronger DPOAEs evoked by low-level primaries. In addition, growth of DPOAEs correlated reliably with perceptual thresholds across frequencies within subjects. Together, the data suggest that short-term dynamic adaptation leading to perceptual sensitization is the result of an active process mediated by the outer hair cells, which are thought to modulate the gain of the cochlear amplifier via efferent feedback.