There is substantial experimental and anatomic evidence suggesting that the human lower esophageal sphincter is not a muscular ring but has its correlate in the arrangement of the so-called muscular clasps and oblique sling fibers at the gastroesophageal junction. We assessed the mode of action of these distinct muscle units in a mechanical model. The arrangement of the clasp and sling fibers at the gastroesophageal junction was simulated with two elastic bands placed perpendicularly around the gastroesophageal junction of four pig specimens. Rapid pullback manometry with four radially oriented pressure transducers was performed in each specimen. The opening pressure was determined, and three-dimensional pressure images were constructed based on the manometric readings. The elastic bands established a competent high-pressure zone at the level of the gastroesophageal junction. The three-dimensional pressure images matched those usually observed in vivo in normal human volunteers. The vector volume of the high-pressure zone correlated with the opening pressure while individual resting pressure values and length of the high-pressure zone were not sufficient to estimate the competence of the gastroesophageal junction in the model. This model supports the contention that the combined action of the clasp and sling fibers establishes the manometric lower esophageal sphincter in humans.
We report a retrospective analysis of 71 patients, operated for primary small bowel tumors (SBT): 47 malignant (66.2%) and 24 benign (33.8%) tumors. Of the malignant tumors, adenocarcinomas predominated (38.3%), followed by neuroendocrine tumors (31.9%), Non-Hodgkin lymphomas (NHL) (12.8%), leiomyosarcomas (10.6%) and other rare entities (6.4%). Morbidity of surgical treatment was 16.9%, 30-day mortality 7%. The estimated 5-year survival rate in malignant lesions was 31.8%. Univariate analysis identified the presence of distant metastasis and the resection status (R status) as prognostic factors (p = 0.034 and p = 0.001). There was no influence of T, N status or grading on survival. A complete macroscopic and microscopic tumor resection has to be the aim of any curative surgical approach in patients with SBT.
Tracheo-bronchial lesions with air leak are rare but a catastrophic complications of esophageal resections. We analyzed the management and outcome of 31 patients who developed a non-malignant lesion of the trachea or main stem bronchus after esophagectomy for esophageal cancer. All patients initially required endotracheal intubation to control respiratory distress. A modified respiratory therapy with a reduced tidal volume and high respiratory rate markedly decreased the air leakage from 2.8 to 1.1/min (P < 0.001). Early extubation was possible in 23 patients with a complete healing or decrease of the fistula size. Jet ventilation, endoluminal stenting of the fistula, bronchoscopic fibrin sealing of the fistula, and surgical closure of the fistula with a muscular pedicle flap were attempted with variable success in patients with otherwise not manageable air leaks. Ten of the 31 patients (33%) died during the postoperative course, in eight out of 10 patients, postoperative mortality resulted from an unhealed lesions at the bifurcation or in the left main stem bronchus. These data show that reduction of airway pressure and spontaneous breathing are the key to closure of the airway leak. The entire armamentarium of respiratory, bronchoscopic, and surgical techniques must be available for a successful management of these patients.
The Angelchik prosthesis appears to be effective in preventing gastroesophageal reflux, although its precise mechanism of action remains controversial. In a unique in vitro model, 10 freshly harvested canine esophagogastric specimens were tested for their ability to remain competent against challenges of intragastric pressure under controlled conditions of intra-abdominal pressure, longitudinal esophageal tension, lower esophageal sphincter pressure and overall length and circumference of the cardia (measure of gastric dilatation). Competency of the specimen was assessed by stepwise variation in the overall length of the sphincter, while keeping constant intraabdominal pressure (20 cm H2O), intragastric pressure (20 cm H2O), esophageal tension (physiologic), lower esophageal sphincter pressure (15 cm H2O) and degree of gastric dilatation (3 cm). With each specimen serving as its own control, the effect produced by the application of an Angelchik prosthesis was evaluated. Results consistently demonstrated that at any lower esophageal sphincter length the percent of competency was increased when the prosthesis was applied (P < 0.01). The findings indicate that the Angelchik prosthesis controls reflux by preventing unfolding of the lower esophageal sphincter when challenged by intragastric pressure.
CorrespondenceThis mechanism may result in more veins regaining competence, thereby improving venous function. Neither of our studies addressed the question of whether small-sized veins (1-2 mm in diameter) are restored to competence by external compression, a mechanism that we suggested may explain the plethysmographic findings of some authors who have shown improved venous function following application of compression hosiery. Finally, Mr Payne and colleagues also mention that the application of compression hosiery reduced the peak reflux velocity. This may be due simply to the fact that stockings raise the interstitial tissue pressure, resulting in a reduced pressure gradient in the veins along the limb, or alternatively that external compression does indeed restore competence in small-sized veins. Our own feelings are that, while compression hosiery may act by restoring competence in large veins, it is unlikely to explain the overall efficacy of compression therapy, and we have turned our attention to investigating the effect on the microcirculation of the skin. This part of the circulation seems to be much more directly influenced by local compression than d o the large veins.
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