Selective surgery and adjuvant therapy based on risk classifications of well-differentiated thyroid cancer.

BACKGROUND: The prognosis of well-differentiated thyroid cancer has been stratified into low- and high-risk groups. These risk groups can be used to predict prognosis and to guide treatment. METHODS: Retrospective study of 962 patients with well-differentiated thyroid cancer treated from 1940 to 1998. Stratification into low- and high-risk groups based on age, metastases, extent, and size (AMES). Effects on survival of surgery, lymph node dissection, and radiation therapy were examined. RESULTS: Seven hundred twenty-eight cases were papillary and 234 were follicular carcinoma. Seven hundred-fifty cases were low risk and 207 high risk. Twenty-year survival was 97.4% in the low-risk patients and 54.0% in high-risk patients (P < 0.001); it was 63.2% in the younger high-risk group and 41.0% in the older high-risk group (P < 0.001). Older high-risk patients had a survival advantage with bilateral thyroidectomy. Extent of surgery did not change survival in either the younger high-risk group or the low-risk group. Lymph node dissection and radioactive iodine ablation did not have an impact on survival. DISCUSSION: Well-differentiated thyroid cancer in low-risk patients has a favorable outcome regardless of treatment. Low-risk patients can be safely treated with unilateral thyroidectomy alone. Risk stratification with a modification of the AMES criteria can be used to guide treatment.

Peritoneal pH during laparoscopy is dependent on ambient gas environment: helium and nitrous oxide do not cause peritoneal acidosis.

BACKGROUND: Little is know about the effects of different insufflation gases on peritoneal pH during laparoscopy. However, these changes may influence the intracellular signalling system, resulting in altered cell growth or adhesiveness. The aim of this study was to determine the effects of carbon dioxide (CO(2)), nitrous oxide (N(2)O), and helium (He) on parietal and visceral peritoneal pH. The effect of different intraabdominal pressures on parietal and visceral peritoneal pH was also examined. METHODS: We conducted both an ambient gas study and a pressure study. For the ambient gas study, 20 pigs were divided into the following four groups: (a) CO(2), (b) He, (c) N(2)O, and (d) abdominal wall lift (Lift) laparoscopy. Parietal and visceral peritoneal pH were measured at 15 min intervals for 180 min. For the pressure study, 15 pigs were divided into the following three groups: (a) CO(2), (b) He, (c) N(2)O laparoscopy. Baseline values were established for parietal and visceral peritoneal pH. Intraabdominal pressure was then increased stepwise at 1-mmHg intervals to 15 mmHg. After pressure was maintained for 15 min at each setting, parietal and visceral peritoneal pH were measured. RESULTS: Ambient gas environment was the major determinant of parietal peritoneal pH. Carbon dioxide caused parietal peritoneal acidosis. Helium, N(2)O, and Lift caused alkalotic parietal peritoneal pH. Intraabdominal pressure had a minor effect on parietal peritoneal pH. At higher intraabdominal pressure (12-15 vs 5-8 mmHg), CO(2) caused a slight decrease in parietal peritoneal pH, whereas N(2)O and He caused a slight increase in parietal peritoneal pH. Visceral peritoneal pH remained relatively unaffected during all studies. CONCLUSIONS: Parietal peritoneal pH during laparoscopy was highly dependent on the ambient gas environment. The effect of intraabdominal pressure on parietal peritoneal pH was of minor significance. Carbon dioxide caused a slight worsening of parietal peritoneal acidosis at higher intraabdominal pressure, whereas, N(2)O, He, and Lift did not cause parietal peritoneal acidosis.

Carbon dioxide pneumoperitoneum causes severe peritoneal acidosis, unaltered by heating, humidification, or bicarbonate in a porcine model.

BACKGROUND: Carbon dioxide (CO(2)) is the most common gas used for insufflation in laparoscopy, but its effects on peritoneal physiology are poorly understood. This study looks at the changes in peritoneal and bowel serosal pH during CO(2) pneumoperitoneum, and whether heating and humidification with or without bicarbonate alters the outcomes. METHODS: Twenty-one pigs divided into four groups as follows: (1) standard (STD) laparoscopy (n = 5); (2) heated and humidified (HH) laparoscopy (n = 6); (3) heated and humidified with bicarbonate (HHBI) laparoscopy (n = 5); and (4) laparotomy (n = 5). Peritoneal pH, bowel serosal pH, and arterial blood gas (ABG) were obtained at 15-min intervals for 3 h. RESULTS: Severe peritoneal acidosis (pH range 6.59-6.74) was observed in all laparoscopy groups, and this was unaltered by heating and humidification or the addition of bicarbonate. Bowel serosal acidosis was observed in all laparoscopy groups with onset of pneumoperitoneum, but it recovered after 45 minutes. No significant changes in peritoneal or bowel serosal pH were observed in the laparotomy group. CONCLUSION: CO(2) pneumoperitoneum resulted in severe peritoneal acidosis that was unaltered by heating and humidification with or without bicarbonate. Alteration in peritoneal pH may conceivably be responsible for providing an environment favorable for tumor-cell implantation during laparoscopy.

Gastric outlet obstruction secondary to pancreatic cancer: surgical vs endoscopic palliation.

BACKGROUND: Gastric outlet obstruction in patients with pancreatic cancer has a grim prognosis. Open surgical bypass is associated with high morbidity, whereas endoscopic duodenal stenting appears to provide better palliation. METHODS: We reviewed the medical records of patients with gastric outlet obstruction secondary to pancreatic carcinoma who were admitted to our clinic between 1 October 1988, and 30 September 1998. The data included stage of disease, American Society of Anesthesiologists (ASA) class, surgical interventions, complications, and survival. RESULTS: A total of 250 patients with pancreatic cancer were identified. Twenty-five of them (10%) had gastric outlet obstruction. Of these 25, 17 were treated with gastrojejunostomy, six had duodenal stenting (Wallstent), and two were resectable. There was no significant difference between the gastrojejunostomy group and the duodenal stenting group in ASA class or stage of disease. For the gastrojejunostomy group, median survival was 64 days (range, 15-167) and postoperative stay in hospital was 15 days (range, 8-39). For the duodenal stenting group, median survival was 110.5 days (range, 42-212) and postoperative stay was 4 days (range, 2-6). Ten patients (58.8%) in the gastrojejunostomy group had delayed gastric emptying. All of the patients in the duodenal stenting group were able to tolerate a soft diet the day after stent placement. Thirty-day mortality in the gastrojejunostomy group was 17.64%; in the duodenal stenting group, it was 0. CONCLUSION: In pancreatic carcinoma patients with gastric outlet obstruction, duodenal stenting results in an earlier discharge from hospital and possibly improved survival.

The use of laparoscopic ultrasonography in staging abdominal malignancy.

The merit of intraoperative ultrasonography in abdominal surgery has been recognized for several decades and has been well documented in the literature. With the proliferation of laparoscopic abdominal surgery, laparoscopic ultrasonographic technology rapidly developed and studies have confirmed its value in staging intra-abdominal malignancy. The combination of diagnostic laparoscopy and laparoscopic ultrasonography has been shown to be consistently superior to other preoperative imaging modalities in the staging of abdominal malignancy. Consequently there has been an improvement in the management of patients with abdominal malignancy, demonstrated by reductions in nontherapeutic laparotomies, improved resectability rates, and optimization of palliation.

Laparoscopic repair of traumatic gastric perforation using a gasless technique.

Laparoscopy has been used in the evaluation of injuries secondary to blunt and penetrating trauma. In this case report, we describe the use of a new gasless laparoscopic technique using conventional instruments to successfully evaluate and repair a traumatic gastric perforation.

Gasless laparoscopy and conventional instruments. The next phase of minimally invasive surgery.

OBJECTIVE: To assess the capability of a retractor system that permits laparoscopic surgery without pneumoperitoneum and to determine if the system facilitates the use of conventional surgical instruments during minimally invasive surgery. DESIGN: Prospective evaluation and data collection with review. SETTING: University-affiliated county hospital. PATIENTS: Twenty-nine male and 29 female subjects evaluated prospectively via 27 trauma-related and 31 elective procedures. METHODS: Fifty-eight laparoscopic procedures were performed between July 1992 and February 1993 with a system consisting of an intra-abdominal fan retractor and an electrically powered mechanical arm using conventional surgical and laparoscopic instruments. RESULTS: Gasless laparoscopy was used in the evaluation of 27 patients with abdominal trauma (11 gunshot wounds, 11 stab wounds, and five blunt injuries). The need for celiotomy was obviated in 20 (74%) of 27 cases. Three enterotomies, two diaphragmatic lacerations, and one gastric perforation were repaired with conventional instruments. Gasless laparoscopic techniques were also used in cholecystectomy (n = 26), diagnostic laparoscopy (n = 3), and appendectomy (n = 2). Exposure similar to that obtained by pneumoperitoneum was obtained in 30 (97%) of 31 cases. One major (trocar tip enterotomy) and two superficial wound infections occurred in this group. The ability to use conventional surgical instruments was advantageous in several cases. CONCLUSIONS: Comparable exposure was achieved in this cohort of patients with gasless laparoscopy. The use of conventional surgical instruments provides an advantage with this technique. Further improvements in abdominal wall lift systems and modification of existing surgical instruments may expand the role of gasless laparoscopy.

Multivariate analysis of morbidity and mortality from the initial surgical management of obstructing carcinoma of the colon.

Eighty consecutive patients presenting with complete large intestinal obstruction from primary carcinoma were evaluated. A multivariate analysis was performed to evaluate perioperative morbidity and mortality. There were five deaths in the immediate postoperative period (30 days). Extensive and lesser complications occurred in eight and 11 patients, respectively. There were 25 lesions of the right colon, whereas in 55 patients, the lesion was located distal to the left branch of the middle colic artery. Females were more likely to present with obstructed carcinomas of the left colon than males. Patients with an obstruction of the left colon more frequently presented with dehydration than those with a tumor of the right colon (p less than 0.05). Most carcinomas of the right colon were resected, whereas lesions of the left colon were managed with diverting colostomy in 33 patients and by primary resection in 22. Thirteen patients with carcinomas of the left colon had an immediate anastomosis without mortality. Preoperative severe cardiopulmonary disease, Acute Physiology and Chronic Health Evaluation score and advanced carcinoma (Dukes' C or D) were statistically related to early hospital morbidity and mortality, while individual physiologic parameters, site of lesion or operation performed were not. Primary resection may be performed safely in selected patients. Multivariate assessment and clinical staging may allow for appropriate patient selection and improve immediate outcome.