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Biomedical subjects

D I Watson

Publications and source records attributed to D I Watson.

At least 55 records · Page 3Linked to original sources
PubMed2000

Laparoscopic antireflux surgery in the treatment of gastroesophageal reflux in patients with Barrett esophagus.

BACKGROUND: Patients with gastroesophageal reflux and Barrett esophagus may represent a group of patients with poorer postoperative outcomes. It has been suggested that such patients should undergo open rather than laparoscopic antireflux surgery. HYPOTHESIS: The laparoscopic approach to antireflux surgery is appropriate treatment for patients with Barrett esophagus who have symptomatic gastroesophageal reflux disease. METHODS: The outcome of 757 patients undergoing laparoscopic surgery for gastroesophageal reflux disease from January 1, 1992, through December 31, 1998, was prospectively examined. Barrett esophagus was present in 81 (10.7%) of these patients (58 men and 23 women). The outcome for this group of patients was compared with that of patients undergoing surgery who did not have Barrett esophagus. RESULTS: The types of operation performed were similar for the 2 patient groups. The mean +/- SD length of columnar mucosa was 47.4 +/- 43.6 mm. The average +/- SD operation time was 79.0 +/- 33.4 minutes. Conversion to open surgery occurred in 6 patients. Postoperative outcomes were as follows. Esophageal manometry and 24-hour pH studies before and after laparoscopic fundoplication demonstrated a significant increase in lower esophageal sphincter resting and residual relaxation pressures and a significant decrease in distal esophageal acid exposure. Four patients have developed high-grade dysplasia or invasive cancer within 4 years of their antireflux surgery, and all of these have subsequently undergone esophageal resection. CONCLUSIONS: The outcome of laparoscopic antireflux surgery is similar for patients with Barrett esophagus compared with other patients with gastroesophageal reflux disease. This suggests that laparoscopic surgery is appropriate treatment for this patient group.

Barrett Esophagus↗
PubMed2000

Influence of gases on intraperitoneal immunity during laparoscopy in tumor-bearing rats.

Laparoscopy has been associated with metastases to abdominal wall wounds. In addition, many recent experimental studies suggest that laparoscopy is associated with increased tumor dissemination. It is possible that immune or metabolic disturbances due to the use of a pneumoperitoneum could contribute to this problem. To investigate this possibility, we studied the effect of two insufflation gases and gasless laparoscopy on in vivo peritoneal macrophage function and intraperitoneal pH in an experimental model. A carcinoma was implanted into the flank of 32 experimental rats that underwent laparoscopic surgery in one of four treatment groups: anesthesia alone, gasless laparoscopy, helium insufflation, and CO2 insufflation. Intraperitoneal pH was monitored during surgery, and peritoneal macrophage function was determined 3 days after surgery by harvesting peritoneal macrophages and then examining their ability to produce tumour necrosis factor-alpha (TNF-alpha). CO2 insufflation was associated with a consistent fall in intraperitoneal pH and a significant reduction in TNFalpha production. These findings did not occur in the other study groups. The results of this study demonstrate that CO2 insufflation results in depressed intraperitoneal macrophage activity. It is possible that it is mediated by pH changes. In addition, it could be a contributing factor to the development of port-site metastases. Further studies are needed to determine whether the factors identified act during clinical surgery.

Animals↗
PubMed2000

The effect of immune enhancement and suppression on the development of laparoscopic port site metastases.

BACKGROUND: Recent clinical case reports and experimental studies have suggested that laparoscopic cancer surgery is associated with an increased risk of tumor spread to abdominal wall wounds. While the etiology of this problem was initially believed to be related to mechanical contamination of wounds, it is now recognized that there are other contributory factors, including disturbed immune function within the peritoneal cavity. To investigate this question further, we evaluated the effect of immune modulation within an established laparoscopic cancer model. METHODS: Eighteen immune-competent syngeneic rats underwent modulation of their immune system, followed 18 h later by laparoscopy with the introduction of a suspension of adenocarcinoma cells into the peritoneal cavity. Rats were randomly allocated to receive either systemic cyclosporin (immune suppressor), intraperitoneal endotoxin (immune enhancer), or no agent (controls). Seven days later, all rats were killed and their peritoneal cavity was inspected for tumor implantation and port site metastases. RESULTS: Cyclosporin did not influence the study outcome, but tumor growth (p = 0.008) and port site metastases (p < 0.0001) were less common following the administration of intraperitoneal endotoxin. CONCLUSION: The results of this study suggest that the immune system plays a role in the genesis of port site metastases. A preventive role for endotoxin in patients undergoing laparoscopic cancer surgery, however, remains speculative.

Abdominal Muscles↗
PubMed2000

Efficacy of a 90 degree anterior fundoplication vs a total fundoplication in an experimental model.

BACKGROUND: The surgical treatment of gastroesophageal reflux disease (GERD) has improved greatly, so that excellent long-term control of symptoms can now be achieved. At present, the gold standard for treatment is the Nissen fundoplication. However, this procedure produces side effects in some patients, including persistent dysphagia, epigastric bloating, and excessive flatulence. As a result, some surgeons who have recommended the use of a partial fundoplication to lessen the occurrence of these side effects. The aim of this study was to determine the efficacy of a laparoscopically constructed 90 degree anterior fundoplication and to compare this method with the Nissen fundoplication. METHODS: Twelve domestic white pigs underwent initial esophageal myotomy to ensure an incompetent lower esophageal sphincter. These animals were then randomized to undergo either a total fundoplication or a 90 degree wrap. All procedures were completed laparoscopically. Resting lower esophageal sphincter pressures were measured immediately and at 2 weeks postoperatively with a water-perfused esophageal manometry catheter incorporating a Dent sleeve. The efficacy of the antireflux barrier was determined at 2 weeks after surgery by fundoplication yield studies. RESULTS: Both the total fundoplication and the 90 degree wrap produced an increase in resting lower esophageal sphincter pressure and restored adequate competence to the gastroesophageal junction in the early postoperative period. CONCLUSION: A laparoscopically completed 90 degree anterior fundoplication restores lower esophageal sphincter competence in the early postoperative period. Clinical studies examining the long-term results and significant side effects of this procedure are required to establish the place for this procedure in the antireflux surgery armamentarium.

Animals↗
PubMed2000

Early reoperation following laparoscopic antireflux surgery.

PURPOSE: To assess the outcome for patients undergoing early reoperation following laparoscopic antireflux surgery. METHODS: The outcome was prospectively determined for 28 patients who underwent 30 reoperative procedures within 4 weeks of their initial laparoscopic fundoplication between 1992 and 1998. Follow-up ranged from 3 months to 4 years (median 2 years). Before mid 1994, patients were assessed and managed based on clinical findings (first 192 patients in overall series), whereas subsequently (for the most recent 530 patients) all patients underwent routine early postoperative barium swallow radiography, and laparoscopic exploration during the first postoperative week if problems were suspected. RESULTS: The reoperations were performed for acute paraoesophageal hiatus hernia (8 patients), tight oesophageal hiatus (7), postoperative haemorrhage (3), tight Nissen fundoplication (8), early recurrent reflux (1), and coeliac/superior mesenteric artery thrombosis (1). Two patients required a second operation for persistent dysphagia due to a tight hiatus. Both patients initially underwent loosening of their fundoplication. Before mid 1994, reoperations were usually undertaken by an open approach, whereas subsequently a laparoscopic approach has usually been successful. Laparoscopic reintervention was easily achieved within 7 days of the first procedure whereas subsequent surgery was more difficult and often required open surgery. The change in protocol was associated with an improvement in overall patient satisfaction and dysphagia in the latter part of this experience. CONCLUSIONS: Routine early contrast radiology following laparoscopic fundoplication and a low threshold for laparoscopic reexploration facilitates early identification of postoperative problems at a time when laparoscopic correction is easily achieved. This may result in an improved overall outcome for patients requiring early reintervention following laparoscopic antireflux surgery.

Barium Sulfate↗
PubMed2000

The influence of esophageal length on outcomes after laparoscopic fundoplication.

BACKGROUND: It has been suggested that laparoscopic antireflux surgery has been associated with an increased incidence of postoperative paraesophageal hiatus herniation, and that this comes (at least in part) from not performing an esophageal lengthening procedure in patients with preoperative esophageal shortening. This study was undertaken to determine whether patients with esophageal shortening have an increased risk of reoperation after laparoscopic antireflux surgery. STUDY DESIGN: All patients who underwent a laparoscopic fundoplication between December 1991 and March 1999, and who had undergone preoperative esophageal manometry in our department were included in this study. Preoperative, operative, and followup data were collected prospectively, and original manometry recordings were reviewed to determine the length of the esophagus (the distance between the midpoints of the upper and lower esophageal sphincters). An index of esophageal length versus height was also calculated by dividing esophageal length by height. Esophageal length and the index were then compared with clinical outcomes. In addition, outcomes for the 50 patients with the shortest index was compared with outcomes of the 50 patients with the longest index. RESULTS: This study included 484 patients from an overall experience of 774 laparoscopic antireflux procedures. Postoperative followup ranged from 3 months to 5 years (median 2 years). Mean esophageal length was 23 cm (range 14 to 30 cm). There was a significant correlation between height and esophageal length (r = 0.44, p < 0.0001). Although patients with large hiatus hernias tended to have a shorter esophagus, preoperative endoscopic esophagitis grading did not influence length. Esophageal length did not influence the overall requirement for further surgical reintervention, although an analysis of esophageal length in patients who developed specific complications demonstrated that postoperative paraesophageal herniation was more likely in patients with a shorter esophagus, and reoperation for a tight esophageal hiatus was less likely in patients with a short esophagus. The incidence of paraesophageal hernia in the 50 patients with the shortest index was 8% versus 2% in the 50 patients with the longest index (p = 0.36). CONCLUSIONS: Although the overall reoperation rate after laparoscopic fundoplication was not influenced by esophageal length, this study did demonstrate an association between esophageal shortening and postoperative paraesophageal herniation. But the increased risk of this problem is small, and for this reason a case cannot be made for patients with a manometrically short esophagus to routinely undergo an esophageal lengthening procedure.

Adolescent↗
PubMed2000

Changing patterns in the management of gastric volvulus over 14 years.

BACKGROUND: Gastric volvulus is an uncommon condition, which can be difficult to diagnose and treat. This study represents a large series of patients with the condition. METHODS: All patients presenting with gastric volvulus over a 14-year period were reviewed. RESULTS: Some 36 patients (median age 75 years) were identified. Volvulus, usually secondary to a hiatus hernia, presented acutely in 29 patients. The major symptoms were abdominal pain, vomiting and upper gastrointestinal haemorrhage. The most useful investigations were barium contrast studies and upper gastrointestinal endoscopy, which were helpful in 21 of 25 and 11 of 18 patients respectively. Treatment was conservative in five patients, by open surgery in 13 and laparoscopic repair in 18 (three converted to open operation). There were no major complications and no deaths. Median hospital stay was shorter in patients treated by laparoscopic rather than open surgery (6 (range 4-36) versus 14 (7-50) days; P < 0.05). CONCLUSION: Acute and chronic gastric volvulus can be treated successfully by either open or laparoscopic surgery. However, laparoscopic surgery now represents a safe and acceptable approach, with minimal morbidity and a significantly shorter hospital stay. This is likely to be of considerable benefit for the treatment of a predominantly elderly population, often with significant co-morbidity.

Adult↗
PubMed2000

Detection of bile reflux: in vivo validation of the Bilitec fibreoptic system.

The Bilitec ambulatory bile reflux monitor is advocated for the assessment of bile reflux. However, it has only been validated by bench top (in vitro) studies. This in vivo study used controlled 'iatrogenic' episodes of bile reflux to determine the ability of the Bilitec system to detect bile acids in the oesophageal lumen. At least 10 ml of fluid was aspirated from the stomach of each of 32 patients, and analysed quantitatively for total bile acids (TBA) and total bilirubin (TB). An in vitro assessment of this fluid with the Bilitec probe was performed initially. The Bilitec probe was then sited in the distal oesophagus, and the gastric fluid was introduced into the mid-oesophagus, through a naso-oesophageal tube, as a series of 10-ml volumes of varying dilutions (1:8, 1:4, 1:2, undiluted) to simulate gastro-oesophageal reflux events. Intraoesophageal bilirubin absorbance was compared with TBA and TB for each dilution. Both TBA and TB values correlated strongly with bilirubin absorbance in vitro (r = 0.83, p < 0.0001 and r = 0.82, p < 0.0001 respectively). However, this relationship was weaker in vivo (r = 0.64, p = 0.0001 and r = 0.68, p < 0.0001 respectively). Of the dilutions which contained potentially injurious concentrations of bile acid (>1 mmol/L), 77% were associated with absorbance >0.14 (currently accepted absorbance threshold for oesophageal bile reflux). Although in vitro sensitivity of the Bilitec probe to bile acids was excellent, in vivo sensitivity was less reliable, and 23% of significant 'bile reflux' episodes did not exceed the currently recommended Bilitec absorbance threshold for bile reflux. In contrast, false-positive results were unlikely. These findings suggest that the overall accuracy of the Bilitec system is probably sufficient for clinical use, although this method is not sufficiently reliable to be regarded as the gold standard for the evaluation of duodeno-oesophageal reflux.

Adult↗
PubMed2000

Risk factor analysis of post-operative mortality in oesophagectomy.

Oesophagectomy for cancer is associated with a significant incidence of post-operative complications and death, and so this study sought to determine objective criteria which could better predict operative risk. Clinical risk factors for oesophagectomy and the results of objective investigations were assessed prospectively by independent surgical and intensive care specialists and a multivariate analysis was used to develop a scoring system for predicting operative risk. From September 1994 to June 1997, 32 patients from an overall experience of 70 oesophagectomy procedures for cancer at the Royal Adelaide Hospital were entered into this study. Hypertension, a history of previous cigarette smoking and FEV1/FVC were identified as independent predictors of the post-operative outcome. Age and FEV1/FVC were also significantly associated with the occurrence of cardiovascular and pulmonary complications respectively. The average risk score was 4.8 +/- 4.5 (mean +/- SD) for patients who died, 2.9 +/- 2.9 for patients who developed post-operative complications and 2.6 +/- 2.1 for patients who had an uncomplicated recovery. The likelihood of post-operative mortality and morbidity was highest in patients with a score of 5 or more. Mortality rates of different patient groups undergoing oesophagectomy by the same surgeons during the same time period were also compared, showing greatly different mortality rates. Important risk factors can be identified preoperatively, and a scoring system can be used to provide objective criteria which can be used to identify patients at an increased risk of post-operative complications and death. A prospective study of this scoring system is now needed to determine whether it proves useful in rejecting patients for surgery who would otherwise have undergone oesophagectomy.

Adult↗
PubMed2000

Experimental study of effect of embolism of different laparoscopy insufflation gases.

BACKGROUND AND PURPOSE: Whilst carbon dioxide is the gas generally used for insufflation during laparoscopy, several studies have reported adverse effects specifically associated with its use. These effects may be attributable to chemical, metabolic, or immunologic effects specific to CO2. Because helium is chemically, physiologically, and pharmacologically inert, it has been suggested as a possible substitute insufflation gas. However, there has been concern about the potential implications of venous gas embolism during helium insufflation. The aim of this study was to examine the physiological effect of the intravenous injection of He and CO2 in an experimental model. MATERIALS AND METHODS: Eleven domestic white pigs were randomly allocated to receive multiple intravenous injections of increasing volumes of either CO2 or He gas. Cardiorespiratory function was measured, and the intravenous volumes of gas that resulted in cardiac arrest were determined. RESULT: Cardiorespiratory functional measures returned to normal quicker after CO2 than after He injection. Helium injection quickly overwhelmed the animal's ability to compensate and resulted in death at a lower volume than did CO2 injection. CONCLUSIONS: Gas embolism during He insufflation is more likely to be lethal than is CO2 embolism. This scenario is most likely following Veress needle insertion into a large vein. Therefore, if He is to be used for insufflation during clinical laparoscopy, the possibility of venous injection should be minimized by avoiding Veress needle use. Further investigation of the safety of He insufflation is warranted before a role during clinical laparoscopy can be recommended.

Animals↗
PubMed2000

Laparoscopic repair of a hernia of Morgagni using a suture technique.

Morgagni's hernia is a rare cause of a diaphragmatic hernia. The defect tends to be small and asymptomatic. When symptomatic, a trans-thoracic or trans-abdominal repair has been carried out. We report asymptomatic case, presenting in an elderly patient, repaired successfully using a laparoscopic approach and discuss various aspects of technique.

Aged↗
PubMed1999

Importance of dissection of the hernial sac in laparoscopic surgery for large hiatal hernias.

HYPOTHESIS: Laparoscopic repair of large hiatal hernia is an appropriate management strategy. DESIGN: A prospective patient series. SETTING: A university teaching hospital. PATIENTS: All patients with hiatal hernias 10 cm or greater in diameter repaired laparoscopically between February 1, 1992, and September 30, 1998. INTERVENTIONS: Two operative strategies were used for laparoscopic repair: the first, which was used until early 1996, entailed initial esophageal dissection while leaving the sac in the mediastinum. The second involved preliminary dissection of the hernial sac from the mediastinum before dissecting the esophagus. MAIN OUTCOME MEASURES: Successful completion of the procedure using a laparoscopic technique, postoperative complication rate, reoperation rate, and clinical outcome. RESULTS: Eighty-six patients with a large hiatal hernia underwent attempted repair using laparoscopic methods. The median age was 63 years (range, 30-91 years), and 45 patients (52%) were women. There were 30 sliding, 10 rolling, and 46 mixed hiatal hernias. Operating times ranged from 48 to 240 minutes (median, 90 minutes), and 20 procedures (23%) were converted to an open operation. Conversion was significantly more common in the first half of our experience (16 [40%] of 40 patients vs 4 [9%] of 46 patients) before the operative strategy was changed. Esophageal-lengthening procedures were not carried out for any patient. At follow-up of a median of 2 years, 1 patient has moderate dysphagia, 4 patients have reflux symptoms, and 1 patient has undergone further surgery for a recurrent paraesophageal hernia. An overall satisfactory outcome was achieved in 81 patients (94%). CONCLUSIONS: Large hiatal hernias can be treated effectively laparoscopically. Dissecting the sac fully from the mediastinum before dissecting the esophagus helps to safely mobilize the esophagus, and we think changing to this strategy is the main reason for the improved laparoscopic success rate reported in the latter half of this series.

Adult↗
PubMed1999

Influence of cytotoxic agents on intraperitoneal tumor implantation after laparoscopy.

PURPOSE: Recent experimental studies suggest that laparoscopic surgery for abdominal malignancy may be associated with increased tumor implantation. This study investigated the influence of cytotoxic agents (administered intraperitoneally or intramuscularly) on implantation of a tumor cell suspension after laparoscopic surgery in an experimental model. METHODS: Thirty-three Dark Agouti rats underwent laparoscopy with CO2 insufflation and instillation of a tumor cell suspension into the abdominal cavity. Rats were randomly allocated to one of the following study groups (9 rats in the control group, 6 rats in all other groups): 1) control (no intraperitoneal instillation); 2) intraperitoneal normal saline (0.9 percent); 3) intraperitoneal povidone-iodine (Betadine to normal saline 1:10 dilution); 4) intraperitoneal methotrexate (2 doses of 0.125 mg/kg body weight in normal saline administered 24 hours apart); 5) intramuscular injection of 2 doses of 0.125 mg/kg body weight administered 24 hours apart (no intraperitoneal agent). Rats were killed 7 days after the procedure, and the peritoneal cavity and port sites were examined for the presence of tumor. RESULTS: A significant reduction in tumor implantation and port-site metastases was observed in all treatment groups (povidone-iodine and intramuscular and intraperitoneal methotrexate). CONCLUSIONS: This study suggests that tumor implantation after laparoscopic surgery and port-site metastases might be prevented by the intraperitoneal or systemic administration of cytotoxic agents. Further studies are needed to determine whether these findings can be applied to clinical practice.

Animals↗