Anterior gastropexy prevents gastrostomy-induced gastroesophageal reflux: an experimental study in piglets

Effects of Stamm Gastrostomy on Gastric Emptying Rate in Rats

AIM

Although frequency of gastroesophageal reflux (GER) increases after gastrostomy, the role of gastric emptying in GER has not been evaluated. In this study, we examined the effects of Stamm gastrostomy on gastric emptying rate in rats and whether Stamm gastrostomy induces GER or not.

METHODS

Sprague-Dawley rats were divided into three groups. Stamm gastrostomy was done in the first group (SG). Sham operation was carried out in group 2 and the 3rd group served as control. Gastric emptying was assessed using both liquid and solid meals in each group at postoperative 14th day. For solid meal emptying, after fasting of 16 h, the rats were fed for 3 h and gastric emptying rate was measured at the fifth hour. Methylcellulose was used for emptying of liquids and it was given after the animals were fasted for 16 h and gastric emptying rate was measured 30 min later. Histological evaluation for GER was performed in all groups.

RESULTS

GER was observed pathophysiologically in 5 of the 7 rats in SG group. Gastric emptying rates of liquid and solid meals were found to be similar in control, SG or sham groups.

CONCLUSION

Surgical gastrostomy does not affect the gastric emptying of solid and liquid meals in rats. Other mechanisms should be considered in the development of GER observed following gastrostomy.

Ambulatory long-term pH monitoring in pigs

BACKGROUND

pH monitoring has been established as the "gold standard" in the diagnosis of gastroesophageal reflux. Evaluation of experimental antireflux therapy should therefore also include this technique, but a suitable technique in an experimental model did not exist so far. The aim of our study was to establish a reliable method for the evaluation of an experimental reflux model in pigs.

METHODS

A total of 33 German Landrace pigs with an average body weight of 56 (50.2-67.2) kg were included. pH monitoring was performed before and after open cardiomyotomy in each animal. All manipulations were performed under general anesthesia. After manometric localization of the gastroesophageal high-pressure zone, a standard pH probe was inserted into the pharynx through a small needle-punctured canal on the side of the animal's snout and placed under endoscopic guidance with the proximal sensor 3 cm above the lower esophageal sphincter (LES) and the distal sensor in the stomach for reference. The harness to carry the pH recorder on the animal's back consisted of a modified belly strap that enabled the animal to move around without limitation. For analysis the same threshold levels were defined as in humans. Gastroesophageal reflux was induced by cardiomyotomy.

RESULTS

The placement of the standard pH probe was possible in all cases. Inserting the probe on the side of the snout left the animals free to nuzzle, which complies with the normal habits of pigs, without breaking the probes and without being compromised in their natural behavior. Repeated punctures for multiple measurements were easily feasible. We performed up to three examinations in each individual animal. Recording was performed for 48 h. A mean number of 67.3 (+/-9.7) acidic refluxes were registered. The mean number of long acidic refluxes was 3.2 (+/-0.75). For an average total time of 75.5 (+/-14.3) min the pH was below 4 accounting for a fraction time pH below 4 of 3.5% (+/-0.68%). Following cardiomyotomy the number of acidic refluxes increased significantly to 166.1 (+/-21.8) and the number of long refluxes to 17.74 (+/-3.35). The total time of pH below 4 increased to 371.3 (+/-62) min so that the fraction time pH below 4 was 14.5% ( p = 0.0006).

CONCLUSION

pH monitoring should be mandatory in any investigation of antireflux therapy. Our method is easy and secure to perform. It is suitable for other gastrointestinal investigations (Bilitec, long-term manometry) that could be carried out using the same technique. The described data represent the basis for other investigations of experimental antireflux therapy.

Esophageal Acid clearance: more volume-dependent than motility-dependent in healthy piglets

BACKGROUND/AIMS

The present study investigates manometrically in healthy piglets whether esophageal clearance after distension with different volumes of acid is volume-dependent.

METHODS

Sedated, non-intubated piglets (n = 22) underwent stationary manometry of the esophagus with a 4-probe perfused assembly after successive injection of 1, 2, and 3 mL of saline and acid. Simultaneous pH metering allowed assessment of acid clearance. Wave features and clearance times after saline and acid were compared by paired non-parametric tests and Friedman analysis of variance. The linearity of the relationships between the clearance times and the volumes of acid infused were tested after square root transformations by one-way ANOVA repeated measures. The significance level was set at < 0.05.

RESULTS

The motor response was identical after distension with saline and acid except for the largest amount of acid used, which elicited more waves during the first 5 minutes after infusion. Time elapsed until regaining pH4 was longer after higher amounts of acid, but not significantly, whereas that necessary to regain baseline pH was significantly longer after such challenge. Esophageal motility was practically identical after 1 and 2 mL of acid, but it was slightly less effective in the first minute after the 3 mL challenge. There was a linear correlation between clearance times and volumes of acid infused.

CONCLUSIONS

Up to a certain volume, the motor responses of the healthy esophagus to distension with neutral or acid fluids were similar. Acid clearance was more a function of the amount of acid present than of the motor response elicited by its presence. Only when the amount of acid was large, esophageal motor response was worse than that elicited after equivalent volumes of neutral fluid. The present evidence suggests that long episodes of reflux in pH tracings might reflect large volumes of refluxate as well as disturbed motor function.

Individual inactivation of the sphincteric component of the gastroesophageal barrier causes reflux esophagitis in piglets

BACKGROUND/PURPOSE

The lower esophageal sphincter and the diaphragmatic crural sling form the gastroesophageal barrier. This work shows that division of the sphincteric component alone suffices to induce reflux esophagitis in piglets.

METHODS

Male piglets underwent either sham operation (n = 7) or extramucosal myotomy of the gastroesophageal junction (n = 8). Before and 1 week after the operation, pull-through manometry was performed under sedation. Pressures taken on the 4 quadrants at 20 1-mm intervals on both time endpoints were compared by pairwise Wilcoxon tests. The distal esophagus was studied histologically after 8 weeks.

RESULTS

The pressure profiles did not change after sham operation. In contrast, they were significantly flattened in the distal half of the high-pressure zone after myotomy reflecting disappearance of the sphincteric component of the barrier. Esophagitis was seen in all myotomized piglets but in none from the sham group.

CONCLUSIONS

Lower esophageal sphincter myotomy alone with preservation of the crural sling induces reflux esophagitis in piglets. This animal, widely available and not too costly, is an excellent model for gastroesophageal research.

Complications of percutaneous endoscopic gastrostomy with or without concomitant antireflux surgery in 96 children

BACKGROUND/PURPOSE

A study was conducted of the complications of percutaneous endoscopic gastrostomy (PEG) with or without antireflux surgery (ARS).

METHODS

A retrospective review was conducted of all patients, receiving a PEG in the period January 1993 through December 1997. Patients' characteristics including underlying disease, indications, results of preoperative screening, and complications were recorded. PEG placement was performed with the Seldinger technique and, in some cases, under laparoscopic control. In the event of a pathologic pH study during preoperative screening, laparoscopic antireflux surgery (ARS) was added.

RESULTS

Mean age was 5 years and 10 months. The majority of the children were mentally retarded. The main indications for PEG were vomiting, food refusal, inability to swallow, and aspiration. Fifty-nine patients had PEG without ARS. Nineteen of these patients had concomitant laparoscopy. Thirty-seven patients had PEG with ARS. One patient died postoperatively of gastric leakage. PEG-related complications occurred in 31% of the patients. There was a significant higher incidence of complications in the group of patients that underwent ARS together with PEG compared with PEG placement without ARS. Roughly half of the complications were peristomal infection related to the use of T-fasteners and the other half gastroduodenal obstruction caused by the balloon of the gastrostomy catheter, both preventable complications. Preoperative vomiting without a positive pH-study disappeared in most cases after PEG placement. Although the pH study normalized in 34 of 37 patients after concomitant ARS, vomiting persisted in 7 of 17 patients. PEG improved the nutritional status in 75% of the children.

CONCLUSIONS

PEG improved the nutritional status in the majority of the children. However, PEG placement can lead to a considerable amount of complications, especially when combined with ARS. ARS together with PEG is successful in treating GER but does not necessarily cure preexistent vomiting. PEG alone cures vomiting in 80% of the patients and rarely leads to vomiting. There seems no good reason for combining PEG with ARS. Only if symptoms progress after PEG, ARS should be considered. Caretakers and patients should be well informed before placement.

Physiological outcome following laparoscopic highly selective vagotomy. A controlled study in a pig model

Open highly selective vagotomy (HSV) has withstood the rigors of objective evaluation to become the optimal surgical treatment for chronic duodenal ulcer refractory to medical therapy in many centers. Laparoscopic HSV has not been subjected to the same scrutiny before entering clinical practice. A controlled animal study was conducted to demonstrate the physiological validity of laparoscopic HSV. Experimental groups underwent laparoscopic and open highly selective vagotomies, and control groups underwent a sham laparoscopic gastric mobilization or no operative procedure. Gastric acid output was measured by an aspiration technique, liquid gastric emptying was calculated by the double sampling technique of George, and gastroesophageal reflux was assessed by 8-h ambulatory pH monitoring. Laparoscopic HSV was as effective as its open counterpart in reducing basal acid output, and laparoscopic HSV did not interfere with liquid gastric emptying in contrast to open HSV. Neither open nor laparoscopic HSV was observed to precipitate gastroesophageal reflux. These data suggested that the continued use of laparoscopic HSV in clinical practice is appropriate.

Risks and benefits of antireflux operations in neurologically impaired children

Gastro-oesophageal reflux (GER) in neurologically impaired children often causes feeding problems and complications of oesophagitis and is frequently resistant to medical treatment. Fifty neurologically impaired children underwent anterior gastropexy as anti-reflux operation, combined with gastrostomy in 23, between 1976 and 1992. There was no operative mortality. There were 25 early complications in 14 patients and 9 late complications in 9 patients. Twelve patients needed 17 re-operations for delayed gastric emptying [4], intestinal obstruction [3], para-oesophageal hernia [3], oesophageal stenosis [4], and recurrent GER, revision of gastrostomy, subphrenic abscess (one each). Nine patients died during the follow up period. Death in two children was related to the operation (incarcerated para-oesophageal hernia and blow-out of the stomach). Out of 41 survivors, the operation was judged successful in 35. It is concluded that antireflux operations in neurologically impaired children carry a high risk of complications. Preoperative identification of risk factors is not possible. The improvements in the quality of life achieved in the majority of patients outweigh the risks.

Current surgical considerations in gastroesophageal reflux disease in infancy and childhood

An understanding of gastroesophageal reflux disease in infants and children by the clinician requires a working knowledge of 18- to 24-hour esophageal pH monitoring and the motility disorders of the esophagus and stomach that may be associated with gastroesophageal reflux disease. The results of surgical therapy for childhood gastroesophageal reflux disease cannot be assessed accurately without this knowledge. Antireflux operations can be tailored to the child's situation, which includes a combination of clinical symptoms and findings on objective tests for reflux and associated alimentary-tract motility disorders. The presence of severe complications from gastroesophageal reflux disease in "asymptomatic" infants and children is a troublesome and not yet fully defined problem. Special areas include the documentation of gastroesophageal reflux disease as a cause of SIDS, the increased reporting of Barrett's esophagus and adenocarcinoma of the esophagus in childhood, and the effect of associated alimentary-tract motility disorders in children with CNS disease who have gastroesophageal reflux disease requiring surgical intervention.