Unsedated peroral wireless pH capsule placement vs. standard pH testing: a randomized study and cost analysis.

BACKGROUND: Wireless capsule pH-metry (WC) is better tolerated than standard nasal pH catheter (SC), but endoscopic placement is expensive. AIMS: to confirm that non-endoscopic peroral manometric placement of WC is as effective and better tolerated than SC and to perform a cost analysis of the available esophageal pH-metry methods. METHODS: Randomized trial at 2 centers. Patients referred for esophageal pH testing were randomly assigned to WC with unsedated peroral placement or SC after esophageal manometry (ESM). Primary outcome was overall discomfort with pH-metry. Costs of 3 different pH-metry strategies were analyzed: 1) ESM + SC, 2) ESM + WC and 3) endoscopically placed WC (EGD + WC) using publicly funded health care system perspective. RESULTS: 86 patients (mean age 51 ± 2 years, 71% female) were enrolled. Overall discomfort score was less in WC than in SC patients (26 ± 4 mm vs 39 ± 4 mm VAS, respectively, p = 0.012) but there were no significant group differences in throat, chest, or overall discomfort during placement. Overall failure rate was 7% in the SC group vs 12% in the WC group (p = 0.71). Per patient costs ($Canadian) were $1475 for EGD + WC, $1014 for ESM + WC, and $906 for ESM + SC. Decreasing the failure rate of ESM + WC from 12% to 5% decreased the cost of ESM + WC to $991. The ESM + SC and ESM + WC strategies became equivalent when the cost of the WC device was dropped from $292 to $193. CONCLUSIONS: Unsedated peroral WC insertion is better tolerated than SC pH-metry both overall and during placement. Although WC is more costly, the extra expense is partially offset when the higher patient and caregiver time costs of SC are considered. TRIAL REGISTRATION: Clinicaltrials.gov Identifier NCT01364610.

Percutaneous endoscopically assisted transenteric full-thickness gastric biopsy: initial experience in humans.

BACKGROUND: GI neuromuscular diseases (GINMD) can cause severe dysmotility and symptoms. Full-thickness biopsy specimens may help diagnose these disorders histologically. OBJECTIVE: To assess a novel percutaneous endoscopically assisted transenteric (PEATE) biopsy method for obtaining full-thickness gastric tissue in patients with suspected GINMD. DESIGN: Prospective proof-of-concept case series. SETTING: Tertiary care gastroenterology unit. PATIENTS: Ten patients (8 women, mean [standard deviation] age 43 [10] years) with gastroparesis-like symptoms (mean [standard deviation] gastroparesis cardinal symptom index 3.28 [1.46] out of 5) and/or clinical findings suggestive of a gastric GINMD. INTERVENTIONS: All patients underwent PEATE biopsy during standard gastroscopy as an outpatient procedure. Tissue was stained for histology and immunohistochemistry of gut wall elements. Interstitial cells of Cajal (ICC) counts were compared with archived normal gastric tissue from control gastrectomies. MAIN OUTCOME MEASUREMENTS: Biopsy success, complications, histopathological findings according to the London Classification of GINMD. RESULTS: Full-thickness antral tissue suitable for analysis was obtained in 9 in 10 patients (90%). PEATE biopsy was well tolerated by all patients without complications. Histology suggested GINMD in 4 of 9 cases (44%), with possible degenerative leiomyopathy in 2, probable inflammatory leiomyopathy in 1, and abnormal ICC networks (>50% reduction in ICC counts) in 1 patient. LIMITATIONS: PEATE biopsy specimen size is smaller than a standard laparoscopic full-thickness biopsy. CONCLUSIONS: PEATE full-thickness gastric biopsy is a simple and safe method of assessing histopathological abnormalities in gastric GINMD without the need for laparoscopy or general anesthesia.

A novel method of full-thickness gastric biopsy via a percutaneous, endoscopically assisted, transenteric approach.

BACKGROUND: Pathologic changes of the enteric nervous system of the stomach have been described in gastroparesis. Because the enteric nervous system lies within the myenteric plexus between the muscle layers of the stomach, it is not accessible by standard biopsy forceps. Thus, tissue must be obtained by laparoscopy or laparotomy. Obtaining full-thickness biopsies with a less-invasive method would be an ideal alternative. OBJECTIVE: To assess the safety and feasibility of a novel method of gastric, full-thickness biopsy by using a percutaneous, endoscopically assisted, transenteric approach. DESIGN: Experimental pilot study in 3 dogs, approved by the animal care committee. INTERVENTION: Under general anesthesia, dogs underwent gastroscopy, and a suitable biopsy area was chosen, based on indentation of the anterior stomach wall by external finger pressure on the abdominal skin and by endoscope transillumination. Using sterile technique, we made a 3-mm incision through the abdominal skin, and a spring-loaded, 14-gauge biopsy needle was used to take 4 separate antral biopsies from each dog, with no mucosal or abdominal closure intervention. MAIN OUTCOME MEASUREMENTS: Feasibility of obtaining enteric nervous system tissue; morbidity and mortality at 4 weeks; gross pathology at necropsy. RESULTS: The procedure was well tolerated by the dogs, with no morbidity or mortality at any time, up to 4 weeks after the procedure. Adequate tissue specimens were obtained for histologic analysis of all layers of the stomach, including enteric nervous system elements. LIMITATIONS: Biopsy size was smaller than a surgical biopsy size. CONCLUSION: The percutaneous, endoscopically assisted, transenteric approach, full-thickness biopsy technique is safe and obtains enteric nervous tissue in a simple, minimally invasive manner.

Parametric study of neural gastric electrical stimulation in acute canine models.

Manipulation of gastric motility by gastric electrical stimulation (GES) has been suggested as a minimally invasive alternative treatment of gastric motility disorders and obesity. However, only neural GES (NGES) has been successful in invoking gastric contractions. Nevertheless, the relationship between these contractions and the controlling NGES parameters has not been quantified. We aimed at determining the relationship between the electrical energy delivered to the tissue as a function of NGES parameters, and the strength and duration of the resulting invoked gastric contractions. Five healthy mongrel dogs underwent subserosal prepyloric implantation of two NGES electrode pairs. Gastric motility was captured by a force transducer implanted in the vicinity of the distal pair of stimulating electrodes. Custom-designed implantable stimulator delivered NGES with 8-16 V (peak-to-peak) amplitudes, and 60-100% duty cycles. Normalized motility index (MI) was utilized to quantify the contractions recorded from the force transducer. The MI increased with increasing voltage amplitudes. However, it remained remarkably constant across all duty cycles when voltage was held constant. Calculated motility generation efficiency indices (MGEI) indicated that highest energy efficiency for invoked motility was achieved at the lowest duty cycle. The parametric data obtained in the present study can be utilized to optimize the power efficiency of implantable gastric neurostimulators.

Implantable neural electrical stimulator for external control of gastrointestinal motility.

Functional electrical stimulation has been suggested as a possible avenue for treating a variety of gastrointestinal motility-related disorders such as gastroparesis, chronic constipation and morbid obesity. The aims of the present study were to design a radio-frequency controlled multi-channel implantable neural gastrointestinal electrical stimulator and test it in an acute canine model. The stimulation parameters can be reprogrammed after implantation, allowing the execution of parametric studies and the investigation of their efficacy in producing controlled gastrointestinal contractions. Bipolar pulse trains of 50Hz frequency, 8-16V(pp) amplitude, 10-100% duty cycle, 1-120s duration, and 2s to 1h pause between successive stimulation sessions were delivered to the stomachs of nine dogs. The resulting contractions were measured by force transducers and digitally recorded on a personal computer. The acute studies confirmed the effectiveness of electrical stimulation in producing invoked gastric contractile activity under the control of the implantable neurostimulator.

Pre-pyloric neural electrical stimulation produces cholinergically-mediated reverse peristalsis in the acute canine model of microprocessor-invoked gastric motility for the treatment of obesity.

BACKGROUND: Gastric Electrical Stimulation (GES) has been suggested as a new tool for the treatment of obesity. Among the known methods for GES, only Neural Gastric Electrical Stimulation (NGES) provides direct control of contractility without utilizing the spontaneously existing gastric electrical activity as an intermediary. However, only one of the established GES techniques, gastric pacing, has been described to produce retrograde peristalsis for delaying gastric emptying. The aim of this study was to explore the possibility of producing retrograde peristalsis using either single electrode set or dual electrode set NGES. METHODS: 8 anesthetized dogs underwent laparotomy and implantation of 2 circumferential electrode sets approximately 3 cm and 7 cm proximal to the pylorus, respectively. Single-set and dual-set NGES sessions were repeatedly administered using a custom-designed implantable neurostimulator. Gastric motility patterns were captured using 3 force transducers implanted on the anterior gastric wall along the gastric axis. Motility indices and velocities were employed to quantify the produced contractile patterns. RESULTS: Both single-set and dual-set NGES produced circumferential lumen-occluding contractions in the vicinity of the electrode sets. The invoked contractions propagated proximally in a retrograde fashion. The propagation scope was different depending on the number of electrode sets used. Different velocities of the invoked retrograde contractions associated with single- and dual-set NGES were observed and quantified. Contractility patterns reflected by the normalized motility indices were very similar regardless of the electrode stimulation technique. CONCLUSION: Pre-pyloric NGES can produce controlled retrograde peristalsis and serve as another avenue for the treatment of obesity.