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Biomedical subjects

A Wyman

Publications and source records attributed to A Wyman.

At least 19 recordsLinked to original sources
PubMed2001

Chromophore-enhanced 805 nm laser therapy for gastrointestinal neoplasia.

BACKGROUND: A new technique of 805 nm semiconductor diode laser-tissue interaction potentiation using indocyanine green (ICG) as an exogenous chromophore has been assessed for use in the palliation of advanced gastrointestinal malignancy. MATERIALS AND METHODS: The tissue effects of ICG potentiated 805 nm laser were assessed both in-vivo using rat stomach and colon, and in vitro using normal and neoplastic human gastric and colonic mucosa. RESULTS: Intravenous ICG did not potentiate the laser-tissue effects of the 805 nm laser in in-vivo studies. Local techniques of ICG application (submucosal injection +/- surface painting of 0.1% ICG solution) enhanced the total depth and diameter of laser induced thermal injury in all in-vitro tissues. Without ICG enhancement thermal tissue injury was minimal in normal gastric and colonic mucosa. CONCLUSION: Local techniques of ICG application enhance laser induced thermal injury in normal and neoplastic gastric and colonic mucosa. This may permit targeting of 805 nm laser-tissue effects with minimal collateral damage during endoscopic laser palliation of advanced gastrointestinal malignancy.

Colon↗
PubMed1996

Laparoscopic truncal vagotomy and gastroenterostomy for pyloric stenosis.

BACKGROUND: Gastric outlet obstruction secondary to chronic duodenal ulceration is an indication for surgery as conservative management with balloon dilatation frequently fails. The standard operation is truncal vagotomy and a drainage procedure. However, development of minimally invasive surgery has revolutionized the surgical approach to this clinical problem. METHODS: Twelve male patients with pyloric stenosis secondary to duodenal ulceration underwent laparoscopic truncal vagotomy and gastrojejunostomy. The perioperative and long term outcome of this group of patients were analyzed. RESULTS: The median operating time was 210 (range 180 to 240) minutes. Median postoperative stay was 6 (range 4 to 41) days. Conversion to laparotomy was necessary in one patient. Delayed gastric emptying occurred in two patients but resolved on conservative measures. At a median postoperative followup of 6 (range 1 to 12) months all patients had a good symptomatic outcome (Visick grades I or II). CONCLUSIONS: Laparoscopic truncal vagotomy and gastrojejunostomy is a feasible technique. Intermediate followup shows good symptomatic results when used for pyloric stenosis.

Adult↗
PubMed1996

Selective use of preoperative endoscopic retrograde cholangiopancreatography in laparoscopic cholecystectomy.

BACKGROUND: The management of possible common bile duct (CBD) stones in patients scheduled for laparoscopic cholecystectomy remains controversial. METHODS: Prospective evaluation of 609 patients who underwent laparoscopic cholecystectomy was carried out in relation to the use of selective preoperative ERCP for detection of common duct stones. Preoperative ERCP was performed if there is or has been (1) cholangitis, biliary pancreatitis, or jaundice; (2) abnormal serum liver tests or (3) ultrasonogram showing a dilated CBD or ductal stones. RESULTS: A total of 139 patients underwent preoperative ERCP, and cannulation of CBD was successful in 133 patients (96%). CBD stones were found in 60 patients (45%) and extracted after sphincterotomy. High prevalence of CBD stones was noted in patients with acute cholangitis and CBD stones on ultrasonogram. There were six endoscopic sphincterotomy-related complications (complication rate, 4.5%): bleeding (2), pancreatitis (3), retroduodenal perforation (1). No patient required surgery as the result of a complication. The prediction of the occurrence of ductal stones was further analyzed using stepwise logistic regression. Acute cholangitis and CBD stones on ultrasonogram were shown to be independent significant risk factors with odds ratios of 8.9 and 13.5, respectively. CONCLUSIONS: With selective preoperative ERCP, suspected CBD stones can be identified and removed prior to laparoscopic cholecystectomy.

Adult↗
PubMed1996

Thoracoscopic resection of oesophageal diverticulum: a case report.

The introduction of video-assisted surgery has revolutionized thoracic surgery. The main attraction is the avoidance of a large thoracotomy incision and its associated morbidity. We present the case of a 55-year-old woman with an oesophageal diverticulum presenting with troublesome dysphagia. A thoracoscopic assisted oesophageal diverticulectomy was performed. Post-operative recovery was uneventful, and only two doses of intramuscular opiate analgesic were required. The patient remained asymptomatic at a follow-up of 3 months.

Diverticulum, Esophageal↗
PubMed1993

Randomized trial of laser scalpel for modified radical mastectomy.

The efficacy of a contact neodymium yttrium-aluminium-garnet laser scalpel was assessed during breast surgery. Forty consecutive women undergoing modified radical mastectomy were randomized to operation performed with a conventional or laser scalpel. The laser scalpel was associated with a significant reduction in mean operative blood loss (149 versus 421 ml; 95 per cent confidence interval of difference 176-368 ml, P < 0.001), but the mean operating time was longer (105 versus 80 min; 95 per cent confidence interval of difference 16-34 min, P < 0.001). No significant differences were found in the volume of postoperative wound drainage, incidence of axillary seroma, postoperative pain score or time to return of shoulder mobility. Use of a laser scalpel in breast surgery cannot be recommended.

Adult↗
PubMed1993

Inflammatory pseudotumour of the liver.

Inflammatory pseudotumours of the liver are uncommon, usually mistaken for malignant lesions and resected. This report describes the presentation of an inflammatory pseudotumour of the liver in a 28-year-old male which was demonstrated on C.T. scanning and diagnosed by percutaneous needle biopsy. This case was treated conservatively and spontaneously resolved within four months, emphasising the need to consider this lesion in the differential diagnosis of an intrahepatic mass.

Adult↗
PubMed1992

Effect of tissue pressure on contact laser insults.

The effect of variations in tissue pressure transmitted through contact laser probes during tissue ablation has been investigated. Weights of 10 and 50 g were transmitted through the tip of the probes onto the gastric and colorectal wall. At all laser energies the depth of tissue vaporization was significantly greater at the higher tissue pressure with perforation of the viscus occurring at laser energies above 10 J. The lateral zones of thermal tissue necrosis were not influenced by tissue pressure. Deformation of the wall of the viscus under the pressure of the probe was identified as a sign of excessive tissue pressure likely to result in perforation of any tissue of similar thickness to the normal gastric or colorectal wall.

Humans↗
PubMed1992

Preliminary evaluation of a new high power diode laser.

A high-powered semiconductor diode laser (805 nm) has recently been developed for medical use. The laser-tissue interactions of this wavelength have been compared with Nd:YAG (1064 nm). When used in the contact mode, the extent of tissue vaporization and zones of thermal necrosis produced by these two lasers were similar. The diode laser was also an effective and haemostatic laser scalpel. This compact laser unit has potential advantages over existing Nd:YAG lasers.

Animals↗
PubMed1992

Radical breast surgery with a contact Nd:YAG laser scalpel.

The use of a contact Nd:YAG laser scalpel during radical and modified radical mastectomy was evaluated in 18 patients with carcinoma of the breast. The laser scalpel performed well as a haemostatic tool, the associated mean blood loss for modified radical mastectomy being 132 ml. Operating time, operative blood loss, laser energy required and postoperative wound drainage were all related to patient obesity, correlating significantly with body weight and/or breast weight. The incidence of axillary seroma was not reduced by laser surgery and occurred in 53% of patients undergoing modified radical mastectomy. The Nd:YAG laser scalpel is an excellent haemostatic tool but it does not appear to have any other advantages over conventional surgery for mastectomy.

Adult↗
PubMed1991

Partial meniscectomy using the neodymium:YAG laser. An in vitro study.

We have evaluated, in an in-vitro study, the thermal effects of the neodymium:YAG (Nd:YAG) contact laser on meniscal tissue. There was no significant difference with regard to time taken to divide the meniscus or depth of necrosis between the two power settings used (25 and 30 W). A significantly greater (p less than 0.005) amount of energy, however, was expended at the higher power setting. The heat from the laser probe dissipated rapidly into the surrounding water without causing significant lateral thermal tissue damage. The Nd:YAG contact laser has features such as the ability to be transmitted through aqueous solutions, fiberoptic delivery, precise thermal tissue effects, and tactile feedback that would be beneficial in arthroscopic surgery. Although experimental, we suggest further clinical evaluation of its potential.

Humans↗
PubMed1991

Management of generalized faecal peritonitis--can we do better?

Generalized faecal peritonitis is associated with a mortality of over 50% in most series of cases. Despite great improvements in the standards of intensive care the morbidity and mortality associated with this condition have not improved, in part due to recurrent intra-abdominal sepsis. This preliminary study investigated the role of laparotomy, repeated abdominal lavage and debridement to determine whether such a policy might lead to an improvement in outcome. Of six cases studied three had perforated diverticular disease, two had Crohn's disease. Twenty lavages were performed on these six patients who had a mean ICU stay of 8 days. Five out of the six patients left hospital and remain well, one patient died of septicaemia and pre-existing renal failure. This study found that laparotomy, repeated abdominal lavage and debridement may be effective in reducing the morbidity and mortality of generalized faecal peritonitis and further study of this technique is appropriate.

Adult↗