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Biomedical subjects

T G John

Publications and source records attributed to T G John.

At least 19 recordsLinked to original sources
PubMed2006

Repeat hepatic resection for recurrent colorectal liver metastases is associated with favourable long-term survival.

BACKGROUND: The management of patients with recurrent colorectal liver metastases (RCLM) remains controversial. This study aimed to determine whether repeat liver resection for RCLM could be performed with acceptable morbidity, mortality and long-term survival. METHODS: Of 1121 consecutive liver resections performed and prospectively analysed between 1987 and 2005, 852 'curative' resections were performed on patients with colorectal liver metastases. Single liver resection was performed in 718 patients, and 71 repeat hepatic resections for RCLM were performed in 66 patients. RESULTS: There were no postoperative deaths following repeat hepatic resection compared with a postoperative mortality rate of 1.4 per cent after single hepatic resection. Postoperative morbidity was comparable following single and repeat hepatectomy (26.1 versus 18 per cent; P = 0.172), although median blood loss was greater during repeat resection (450 versus 350 ml; P = 0.006). Actuarial 1-, 3- and 5-year survival rates were 94, 68 and 44 per cent after repeat hepatic resection for RCLM, compared with 89.3, 51.7 and 29.5 per cent respectively following single hepatectomy. CONCLUSION: The beneficial outcomes observed after repeat liver resection in selected patients with RCLM confirm the experience of others and support its status as the preferred choice of treatment for such patients.

Adult↗
PubMed2005

Hepatic resection for malignant melanoma.

INTRODUCTION: Patients with metastatic melanoma have a poor prognosis with a median survival of approximately 6 months. There is a paucity of data regarding the natural history of the disease in the small subset of patients who are suitable for hepatic resection for metastatic disease confined to the liver. PATIENTS AND METHODS: Five patients were identified from a prospectively collected database of over 1000 liver resections performed in Basingstoke between 1986 and 2004. Clinical details and survival were analysed. RESULTS: Two patients died within 12 months of resection from extrahepatic disease. The other three patients are alive and disease-free at 76, 92 and 147 months, respectively. DISCUSSION: In carefully selected cases, hepatic resection for metastatic melanoma to the liver can result in long-term survival. Criteria for selection of patients as suitable for resection remain unclear.

Aged↗
PubMed2005

Biopsy of resectable colorectal liver metastases causes tumour dissemination and adversely affects survival after liver resection.

BACKGROUND: Liver resection is increasingly being performed for metastatic colorectal cancer. This study assessed the need for preoperative biopsy of suspected metastases and whether biopsy has any effect on long-term survival. METHODS: Prospectively collected data on patients who underwent liver resection for colorectal metastases between 1986 and 2003 were reviewed retrospectively. The endpoints of morbidity, operative mortality and long-term survival were compared between patients who had biopsy before referral (group 1) and those who did not (group 2). RESULTS: Patient demographics and disease distribution were similar for 90 patients in group 1 and 508 in group 2. Seventeen patients (19 per cent) who had undergone biopsy either at the time of colorectal resection or radiologically had evidence of needle-track deposits. Operative mortality and morbidity rates in the two groups were similar. The 4-year survival rate after liver resection was 32.5 (s.e. 5.5) per cent in group 1, compared with 46.7 (2.8) per cent in group 2 (P = 0.008). CONCLUSION: Needle-track deposits are common after biopsy of suspected colorectal liver metastases. Biopsy of metastases confers poorer long-term survival on patients after liver resection and cannot be justified in patients with potentially resectable disease.

Biopsy, Needle↗
PubMed1999

Laparoscopy with laparoscopic ultrasonography in the TNM staging of pancreatic carcinoma.

A prospective study was performed comparing laparoscopy with laparoscopic ultrasonography (LapUS), transabdominal ultrasonography (USS), computed tomography (CT), and selective visceral angiography with portal phase venography (SVA) for the assessment of resectability in 50 patients with pancreatic or periampullary cancer. The results were stratified by TNM stages. Tumor unresectability was demonstrated in 36 patients (72%). The sensitivity of LapUS for demonstrating the index lesion was 96%. Laparoscopic ultrasonography failed to predict factors precluding resection by T stage in six patients, and there were no significant differences in the ability of any modality to predict local resectability (predictive value 58-73%). Laparoscopic ultrasonography did not overestimate T stage and was significantly more specific for assessing unresectability compared with USS (100% vs. 64%, p<0.05) and CT (100% vs. 47%, p<0.005). No imaging investigation was able to assess the N stage accurately. Metastases were confirmed in 16 patients (32%), with LapUS proving significantly more sensitive than USS (94% vs. 29%, p<0.001) and CT (94% vs. 33%, p<0.005). The addition of LapUS to the laparoscopic examination did not change the M stage in any patient, as all metastases were superficially located. Laparoscopy with LapUS was the most reliable method for assessing overall tumour resectability and was significantly more predictive than CT (97% vs. 79%, p<0.005). These results confirm that laparoscopy is indispensable for detecting occult intraabdominal metastases. LapUS reliably predicts tumor unresectability, offsetting the tendency of USS and CT to overestimate T stage. Methods of accurate N staging remain elusive, and the use of routine SVA is not justified.

Adult↗
PubMed1999

Role of laparoscopic ultrasonography in the management of patients with oesophagogastric cancer.

BACKGROUND: Laparoscopy and laparoscopic ultrasonography (lapUS) have been shown to improve the staging of patients with oesophagogastric cancer but there remains doubt as to whether most benefit follows laparoscopy alone and how much is contributed by the addition of lapUS. METHODS: The role of lapUS in surgical decision making was evaluated prospectively in a consecutive series of patients with oesophagogastric cancer following conventional radiological assessment. The results of the lapUS findings over and above the laparoscopic findings were documented in order to identify the additional benefit of lapUS. RESULTS: After initial conventional assessment 41 patients were considered unsuitable for surgery and treated by palliation, with a further 25 patients proceeding to surgery without laparoscopy. Of the 93 patients who underwent laparoscopy, 18 were shown to have irresectable disease and avoided further surgery; a further seven avoided inappropriate surgery by the addition of lapUS. The open-close laparotomy rate was reduced from five of 25 in patients who did not undergo laparoscopy to nine (12 per cent) of 75 by the introduction of laparoscopy and to two (3 per cent) of 68 with the addition of lapUS. CONCLUSION: Laparoscopy alone prevented unnecessary surgery in 18 (19 per cent) of 93 patients with oesophagogastric cancer and the addition of lapUS identified a further seven patients (8 per cent) in whom unnecessary surgery was avoided.

Adenocarcinoma↗
PubMed1998

Contractile response of isolated human hepatic arteries to alpha-adrenoceptor agonists is not impaired in patients with cirrhosis.

1. Impaired vasoconstriction in animals with cirrhosis is maintained in isolated vessels in vitro, indicating an intrinsic alteration in function or structure of the cells in the vascular wall. This may be due to receptor down-regulation, a defect in post-receptor signal transduction or overproduction of vasodilator compounds. This investigation examined the role of these mechanisms in modulating alpha-adrenoceptor-mediated contraction in hepatic arteries from patients with advanced cirrhosis. 2. Hepatic arteries were obtained from subjects with and without cirrhosis for functional investigation in vitro. Endothelial cell function was assessed using endothelium-dependent (acetylcholine) and independent (3'-morpholinosydnonimine) vasodilators. alpha-Adrenoceptor-mediated contraction was assessed by constructing cumulative concentration-response curves to the alpha1-selective agonist phenylephrine, the non-selective adrenoceptor agonist noradrenaline and the receptor-independent vasoconstrictor potassium chloride. 3. None of the vessels used in this study had an intact endothelium but endothelium-independent relaxation was not different in arteries from subject with (79.5+/-10.16%; n=23) and without (84.45+/-18%; n=20) cirrhosis. Phenylephrine, noradrenaline and potassium chloride produced contractions that were of similar size (P>0.05) in arteries from subjects with (10.10+/-0.97 g, 8.85+/-1.03 g and 8.56+/-0.65 g respectively) and without (10.42+/-1.23 g, 9.58+/-1.39 g and 8. 62+/-0.98 g respectively) cirrhosis. The sensitivities (pD2) of the responses to these agonists were also similar (P<0.05) in arteries from patients with cirrhosis (5.45+/-0.10, 5.60+/-0.12 and 1.57+/-0. 03 respectively) and those from non-cirrhotic donors (5.58+/-0.11, 5. 67+/-0.11 and 1.54+/-0.05 respectively).4. Contraction of the denuded hepatic artery was unaffected by cirrhosis indicating that vascular abnormalities in this condition in man are not due to an intrinsic alteration of smooth muscle cell function in hepatic conduit arteries.

Adrenergic alpha-Agonists↗
PubMed1997

Laparoscopic ultrasonography for staging gastroesophageal cancer.

BACKGROUND: TNM staging of gastroesophageal cancer is improved by the use of laparoscopy for the detection of occult metastases and endoscopic ultrasonography for T and possibly N staging. Laparoscopic ultrasonography may combine the strengths of both of these techniques. The purpose of this study was to compare TNM staging by means of laparoscopic ultrasonography (Lap US), laparoscopy, and conventional computed tomography (CT). METHODS: TNM stage was determined by using Lap US, laparoscopy, and CT scanning in 26 surgical candidates with gastric or esophageal cancer in a blinded fashion. CT scans were also reviewed separately by an expert radiologist. Validation of findings was by means of final pathologic examination. RESULTS: Resectability for potential cure was determined by means of Lap US with a sensitivity of 100% and a specificity of 91% versus 100% and 73% for laparoscopy and 75% and 60% for CT, respectively. Overall TNM staging was 82% accurate for Lap US versus 67% for laparoscopy and 47% for CT (chi-squared, 8.64, p < 0.005, and 10.4, p < 0.005, respectively). Accuracies for Lap US versus laparoscopy versus CT for N stage were 92% versus 84% versus 70%, respectively, for T stage were 92% versus 42% versus 60%, respectively, and for M stage were 89% versus 44% versus 62%, respectively. CONCLUSIONS: T and N staging by Lap US were comparable to published results for endoscopic ultrasonography, and overall TNM staging was better. Lap US may provide the optimal preoperative staging for gastric cancer and has the potential to complement endoscopic ultrasonography in staging esophageal cancer.

Adult↗
PubMed1996

Comparison of manual and ultrasonographic evaluation of bladder size in patients prior to laparoscopy.

BACKGROUND: Catheterization of the bladder may reduce laparoscopic complications although an enlarged bladder may be impalpable in overweight patients or following previous lower abdominal surgery. METHODS: This study assessed bladder size by manual examination and transcutaneous ultrasound (US). Consecutive patients (n = 90; median age 55 years [20-85]; 61 females) undergoing laparoscopy were studied prospectively. All patients voided preoperatively and catheterization was performed if estimated US bladder volumes exceeded 300 ml. RESULTS: Manual assessment failed to detect bladder enlargement in any patients (sensitivity: 0%; specificity: 4.4%), whereas ultrasound identified four patients at risk of bladder injury due to unsuspected enlargement (4.4%). Three of these patients were either overweight or obese and one patient had previous lower abdominal surgery. Of 12 patients (13%) catheterized, three had or developed urinary tract infections. CONCLUSIONS: Preoperative voiding does not guarantee bladder emptying. Manual examination does not detect bladder enlargement reliably in the obese patient. Ultrasonography may improve patient selection for catheterization.

Adult↗
PubMed1996

Transjugular intrahepatic portosystemic stent-shunt (TIPSS) insertion as a prelude to orthotopic liver transplantation in patients with severe portal hypertension.

OBJECTIVE: To investigate the impact of preoperative transjugular intrahepatic portosystemic stent-shunt (TIPSS) on patients undergoing liver transplantation. DESIGN: A retrospective non-randomized comparative clinical study. SETTING: Tertiary referral institution. PATIENTS, PARTICIPANTS: Twenty-four patients with liver cirrhosis, portal hypertension and gastro-oesophageal varices who underwent liver transplantation. INTERVENTIONS: TIPSS insertion had been performed preoperatively in 12 patients. MAIN OUTCOME MEASURES: Operative dissection times and blood transfusion requirements during liver transplantation. Postoperative complication rate. Cumulative patient and graft survival. RESULTS: There were no significant differences in outcome measures between patients with and without previous TIPSS insertion with respect to recipient hepatectomy times (mean 192 min (126-280) versus 196 min (145-254)), total operating time (mean 484 min (330-690) versus 486 min (370-580)), intraoperative blood transfusion (mean 11 units (2-29) versus 12 units (2-30)), intraoperative fresh frozen plasma transfusion (mean 9 units (1-16) versus 11 (2-23) units), patient survival (83% versus 92% cumulative 1-year survival), graft survival (80% versus 83% cumulative 1-year survival), or postoperative complication rates. CONCLUSION: TIPSS insertion is feasible and relatively safe as a 'bridge to transplantation' in patients who have had a variceal haemorrhage. There is little evidence that preoperative TIPSS insertion directly affects the performance of liver transplantation as TIPSS neither, hinders nor facilitates surgery or post operative survival. Although it is important that the potential hazards of TIPSS extension into the inferior vena cava or superior mesenteric vein be recognized, liver transplant surgeons need not be unduly concerned about the overall impact of TIPSS as it becomes more universally available in the management of variceal haemorrhage.

Blood Loss, Surgical↗
PubMed1995

Carcinoma of the pancreatic head and periampullary region. Tumor staging with laparoscopy and laparoscopic ultrasonography.

OBJECTIVE: The authors performed a prospective evaluation of staging laparoscopy with laparoscopic ultrasonography in predicting surgical resectability in patients with carcinomas of the pancreatic head and periampullary region. SUMMARY BACKGROUND DATA: Pancreatic resection with curative intent is possible in a select minority of patients who have carcinomas of the pancreatic head and periampullary region. Patient selection is important to plan appropriate therapy and avoid unnecessary laparotomy in patients with unresectable disease. Laparoscopic ultrasonography is a novel technique that combines the proven benefits of staging laparoscopy with high resolution intraoperative ultrasound of the liver and pancreas, but which has yet to be evaluated critically in the staging of pancreatic malignancy. METHODS: A cohort of 40 consecutive patients referred to a tertiary referral center and with a diagnosis of potentially resectable pancreatic or periampullary cancer underwent staging laparoscopy with laparoscopic ultrasonography. The diagnostic accuracy of staging laparoscopy alone and in conjunction with laparoscopic ultrasonography was evaluated in predicting tumor resectability (absence of peritoneal or liver metastases; absence of malignant regional lymphadenopathy; tumor confined to pancreatic head or periampullary region). RESULTS: "Occult" metastatic lesions were demonstrated by staging laparoscopy in 14 patients (35%). Laparoscopic ultrasonography demonstrated factors confirming unresectable tumor in 23 patients (59%), provided staging information in addition to that of laparoscopy alone in 20 patients (53%), and changed the decision regarding tumor resectability in 10 patients (25%). Staging laparoscopy with laparoscopic ultrasonography was more specific and accurate in predicting tumor resectability than laparoscopy alone (88% and 89% versus 50% and 65%, respectively). CONCLUSIONS: Staging laparoscopy is indispensable in the detection of "occult" intra-abdominal metastases. Laparoscopic ultrasonography improves the accuracy of laparoscopic staging in patients with potentially resectable pancreatic and periampullary carcinomas.

Adenocarcinoma↗
PubMed1995

Case report: inferior vena caval thrombosis following severe liver trauma and perihepatic packing--early detection by intraoperative ultrasonography enabling treatment by percutaneous mechanical thrombectomy.

Patients with severe liver trauma present a major challenge in management. We report the successful treatment of a patient presenting with a severe liver injury. The detection of major inferior vena caval thrombosis by intraoperative ultrasonography enabled the use of a percutaneous thrombectomy device to facilitate dissolution of the thrombus.

Adult↗
PubMed1995

A comparative study of emergency transjugular intrahepatic portosystemic stent-shunt and esophageal transection in the management of uncontrolled variceal hemorrhage.

OBJECTIVES: Transjugular intrahepatic portosystemic stent-shunts (TIPSS) have been shown to reduce portal hypertension consistently and have recently been reported to arrest active variceal hemorrhage. This retrospective and nonrandomized study compares the results of TIPSS with esophageal transection (ET) and devascularization in patients with uncontrolled variceal hemorrhage admitted to a single center with an interest in variceal bleeding. PATIENTS AND METHODS: Two hundred and sixty cirrhotic patients have been referred with variceal bleeding over the past 7 yr. In 41 patients (15.8%), hemorrhage was uncontrolled despite two treatments with sclerotherapy. Thirty-eight patients were eligible for analysis. Nineteen were considered for ET and 19 for TIPSS. Patients in the two groups were well matched for age, sex, etiology of liver disease, and its severity and complications. They have been followed for 13 patient years (TIPSS-7, longest 20 months; ET-6, longest 23 months). Data for survival and rebleeding were analyzed by the Kaplan-Meier method on an intention-to-treat basis. RESULTS: Seven of the 19 were considered unfit for surgery, and 12 underwent esophageal transection and devascularization. TIPSS was undertaken successfully in 17 patients, the Palmaz stent being used in 4 and the Wallstent in 13. Successful TIPSS reduced the mean portal pressure gradient from 22.2 (SE 1.2) to 9.7 (SE 0.7) mm Hg (p < 0.001). Mortality within 30 days of the initial bleed was 42% in the TIPSS group compared with 79% in the ET group (p < 0.05). Rebleeding occurred in 15.6% patients with TIPSS, compared with 26.2% in the ET group. Encephalopathy in the two groups of patients was not significantly different (TIPSS 25% and ET 22%). TIPSS was followed by active infection in 20% compared with 36% after ET. CONCLUSIONS: This study shows that the overall mortality in this group of patients is high whatever the type of treatment used. TIPSS can be performed successfully on these patients who are often not suitable for surgery. Mortality rates were significantly lower in patients treated by TIPSS. Compared with ET, TIPSS should be regarded as the preferred mode of treatment for uncontrolled variceal hemorrhage in patients with cirrhosis.

Case-Control Studies↗