Biomedical subjects
Publications and source records attributed to G J Maddern.
Evidence on topical negative pressure from randomised controlled trials, non-randomised comparative studies and case studies is considered. This is the first systematic review on this therapy to consider results by wound type.
BACKGROUND: Palliation of pancreatic cancer remains the only option for the majority of patients. Palliative techniques such as surgical bypass and endoscopic retrograde cholangiopancreatography (ERCP) with stenting are not ideal. The 'ideal' palliative technique would combine the efficacy of surgery with the minimal complications of an endoscopic procedure. Endoscopically delivered perductal electrolytic ablation of pancreatic lesions has the potential to meet these criteria. METHODS: Fifteen pigs were used. The pancreatic duct was cannulated with an electrolysis catheter. Animals were randomised to either: controls, treatment 2-week survivor or treatment 8-week survivor. An electrolytic dose was administered to the treatment animals. Post-operatively, serum amylase and leucocyte count were assessed. Pancreata were histologically examined to detect evidence of acute pancreatitis. RESULTS: Electrolysis was well tolerated. There was no difference in post-operative hyperamylasaemia and leucocyte count between the groups. Histological examination showed inflammation at the ablation site at 2 weeks, by 8 weeks this was replaced by scarring. CONCLUSION: The results of this study suggest that endoscopic perductal electrolytic ablation of the pancreas is feasible and safe. Biochemical and histological findings indicate self-limiting localised inflammation of the pancreas. This technique may have a role in the palliation of pancreatic cancer and warrants further investigation.
It is well documented that pigs frequently die from postoperative acute gastric dilatation, and proximal gastric 'stress' ulceration. Three cases of gastric mucosal 'de-gloving' are reported. This was secondary to acute gastric dilatation and resulted in death from acute haemorrhage. All animals had undergone major abdominal surgery. Histology confirmed that the proximal gastric mucosa had been 'de-gloved', or torn from the gastro-oesophageal junction, leaving exposed muscle fibres. This syndrome has not been reported previously. The postmortem appearances of this mechanical injury could easily be mistaken for extensive oesophago-gastric peptic ulceration. This has major implications for prevention.
BACKGROUND: Pancreatic cancer has a dismal prognosis. Few patients are suitable for surgical resection, leaving the majority requiring symptom palliation. Current palliative techniques such as surgical bypass and endoscopic retrograde cholangiopancreatography (ERCP) are imperfect. A novel palliative therapy combining the symptom control of surgical bypass with the minimally invasive nature of ERCP is required. METHODS: Perductal electrolytic ablation of pancreatic tissue, in a porcine model, was performed. There were two survival groups of 2 weeks (n = 4) and 8 weeks (n = 4). Postoperatively, serum biochemistry, amylase and C-reactive protein (CRP) were assessed. Histological examination of the pancreas, lungs, and kidneys was performed to determine the presence of acute pancreatitis or systemic inflammatory response. RESULTS: An immediate transient increase in both amylase and CRP was seen. Although pancreatic histology demonstrated localised necrosis at the electrolytic site at 2 weeks, there was no evidence of generalized pancreatitis or a systemic inflammatory response at either 2 or 8 weeks. CONCLUSIONS: This study suggests that, although there is localized pancreatic necrosis and transient hyperamylasemia, perductal pancreatic electrolytic ablation is safe, with neither generalized pancreatitis nor a systemic inflammatory response, in the medium and long term. Although performed in normal porcine pancreas, because of the absence of a large-animal model of pancreatic cancer, this study suggests that electrolytic pancreatic ablation is safe. This technique may have a role in the palliation of pancreatic cancer, especially if delivered via a minimally, invasive approach, and warrants further investigation.
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BACKGROUND: Local ablation has been proposed for treatment of liver tumours. Cryoshock, a variant of the systemic inflammatory response syndrome (SIRS), is a potentially fatal complication of cryoablation caused by systemic release of necrotic breakdown products from ablated liver. The proinflammatory cytokines tissue necrosis factor (TNF) alpha and interleukin (IL) 1 are important mediators of this response. This study assessed the risk of SIRS complicating electrolytic liver ablation by measuring circulating levels of inflammatory cytokines, other inflammatory markers and clinical markers of organ function. METHODS: Electrolytic liver ablation was performed in 16 pigs and four pigs served as controls. Platelet count, and serum levels of urea, creatinine, liver enzymes, C-reactive protein (CRP), TNF-alpha and IL-1beta were measured before treatment and for 72 h after the procedure. RESULTS: There were significant dose-related increases in CRP and alanine aminotransferase levels with liver electrolysis. There was no significant derangement in renal function or platelet count following ablation. A rise in serum TNF-alpha and IL-1beta levels was not associated with liver electrolysis. CONCLUSION: There was no evidence of organ failure or significantly raised levels of proinflammatory cytokines as a result of liver electrolysis, suggesting that this is a safe procedure for liver ablation.
BACKGROUND: The aim was to determine the safety and effectiveness of the implantation of an artificial bowel sphincter for the treatment of severe faecal incontinence. METHOD: Medical bibliographic databases, the internet and reference lists were searched from January 1966 to January 2003. Only the lowest level of evidence was available for inclusion in this systematic review. Case series and case reports were selected to assess safety, whereas only case series were selected to assess effectiveness. RESULTS: Fourteen studies met the inclusion criteria. A number of safety issues were reported, including high explantation rates, and rates of adverse events owing to infection, device malfunction, ulceration and pain. Results in published reports were not analysed on an intention-to-treat basis. Continence, quality of life and manometry scores were reported for patients with a functioning device at the end of follow-up. These patients experienced a significant improvement in their level of continence. As no outcome data were presented for those with a non-functioning or explanted device, it is possible that such patients may have a worsened degree of incontinence or decreased quality of life. CONCLUSION: Implantation of an artificial bowel sphincter is of uncertain benefit and may possibly harm many patients. Patient selection is therefore critical and should be enhanced by higher-quality research.
BACKGROUND: In-depth knowledge of pig liver anatomy allows potential research into segmental liver resections and hepatic regeneration, as well as liver transplantation techniques. The segmental anatomy, however, remains largely unknown. This study aimed to delineate the segmental anatomy of the porcine liver in comparison with that of the human. METHODS: The segmental anatomy of the porcine liver was determined using acrylic injection casting of ex vivo pig livers, allowing the arterial, venous and biliary supply to be visualized directly. This was correlated using multi-slice computed tomography (CT) and three-dimensional reconstructions. RESULTS: Although the external morphology of the porcine liver differs from that of the human, the segmental anatomy is remarkably similar in term of its vascularity and biliary tree. CONCLUSION: Acrylic casting of the porcine liver accurately delineates the vascular and biliary anatomy, and is a useful tool for performing experimental liver surgery. The similarities between porcine and human segmental anatomy allow domestic swine to be used as a comparable model. Three-dimensional CT reconstructions can also accurately visualize the anatomy and may be used to perform virtual surgery, or to assess segmental volumes.
BACKGROUND: A systematic review was conducted to determine which of the methods of obtaining peritoneal access and establishing pneumoperitoneum is the safest and most effective. METHODS: Studies that met the inclusion criteria were identified from six bibliographic databases up to May 2002, the internet, hand-searches and reference lists. They were critically appraised using a validated checklist and data were extracted using standardized protocols. RESULTS: Meta-analysis of prospective, non-randomized studies of open versus closed (needle/trocar) access indicated a trend during open access towards a reduced risk of major complications (pooled relative risk (RR(p)) 0.30, 95 per cent confidence interval (c.i.) 0.09 to 1.03). Open access was also associated with a trend towards a reduced risk of access-site herniation (RR(p) 0.21, 95 per cent c.i. 0.04 to 1.03) and, in non-obese patients, a 57 per cent reduced risk of minor complications (RR(p) 0.43, 95 per cent c.i. 0.20 to 0.92) and a trend for fewer conversions to laparotomy (RR(p) 0.21, 95 per cent c.i. 0.04 to 1.17). Data on major complications in studies of direct trocar versus needle/trocar access were inconclusive. Minor complications in randomized controlled trials were fewer with direct trocar access (RR(p) 0.19, 95 per cent c.i. 0.09 to 0.40), predominantly owing to a reduction in extraperitoneal insufflation. CONCLUSION: The evidence on the comparative safety and effectiveness of the different access methods was not definitive, but there were trends in the data that merit further exploration.
A spigelian hernia is an uncommon entity. The diagnosis and location of this disorder often is difficult. We present a case in which the hernia could not be located at the time of operation, despite exploration. Laparoscopy performed subsequently enabled location and repair of the hernia under direct visualization, with good results. Laparoscopy is advocated as an adjunct to the diagnosis and treatment of spigelian hernia.
BACKGROUND: Inoperable pancreatic cancer has a dismal prognosis. Palliation involves either stenting or surgical bypass. Stenting does not relieve gastric outlet obstruction, and surgical bypass is a major procedure. A minimally invasive procedure is needed that relieves both gastric outlet and biliary obstruction, with the potential for relieving pain. METHODS: In an experimental model, pancreatic electrolysis was investigated. The pancreatic duct was cannulated via a transduodenal approach with an electrode catheter. In 6 animals an electrolytic "lesion" was created using a direct current generator. Six animals were controls. The local and systemic effects of electrolysis were assessed using histological and biochemical parameters. RESULTS: The pancreatic duct was cannulated in all animals and treatment was uneventful. Electrolytic lesions comprised a central area of necrosis with a sharp demarcation between necrotic and viable pancreas. All animals developed transient hyperamylasemia after electrolysis. There was no significant difference between treatment and controls. Importantly, no animal had clinical, biochemical, or histological evidence of pancreatitis. CONCLUSIONS: This experimental study suggested that electrolytic palliation of inoperable pancreatic cancer via the gastrointestinal tract is potentially safe. In patients, this treatment could be performed during endoscopic retrograde cholangiopancreatography and may have therapeutic advantages when compared to stenting or biliary bypass.
Incisional hernias are a recognized complication of all abdominal surgery, including laparoscopic surgery. Although most cases of laparoscopic port incisional hernias are seen in the midline, particularly around the umbilicus, there are several reports of herniation at laterally placed ports. Accepted surgical practice is to close the deep fascial layers at midline laparoscopic ports. However, the deep layers at the lateral ports are not usually closed. Two near-identical cases are reported in which incisional hernias have developed at the site where laterally placed 10-mm ports have pierced the spigelian fascia. Hernia development at an iatrogenic defect in an area that is already potentially weak, and therefore prone to herniation, has implications for lateral 10-mm port site closure. The closure of the deep layers of all lateral laparoscopic ports is advocated, especially if the spigelian fascia is pierced.
HYPOTHESIS: Use of circular stapled hemorrhoidectomy will result in the same or improved safety and efficacy outcomes as those of the conventional methods for hemorrhoidectomy in patients with hemorrhoids. DATA SOURCES: Studies on stapled hemorrhoidectomy were identified using PREMEDLINE and MEDLINE (June 1966-June 2001), EMBASE (January 1980-June 2001), Current Contents (June 1993-June 2001), Ovid HEALTHSTAR (January 1975-June 2001), the National Institutes of Health Clinical Trials database (searched June 13, 2001), and The National Coordinating Centre for Health Technology Assessment database (searched June 14, 2001). The search terms were as follows: haemorrhoid* and (stapl* or convent*) or hemorrhoid* and (stapl* or convent*). The Cochrane Library (2001, issue 2) was searched using the search terms haemorrhoid* or hemorrhoid*. STUDY SELECTION: Articles detailing randomized controlled trials were included if they compared circular stapled with conventional hemorrhoidectomy and provided relevant safety and efficacy outcome information. DATA EXTRACTION: Data from all included studies were extracted using standardized data extraction tables that were developed a priori. In addition, the randomized controlled trials were examined with respect to the adequacy of allocation concealment, handling of those unavailable for follow-up, and any other aspect of the study design or execution that may have introduced bias. DATA SYNTHESIS: Seven randomized controlled trials met the inclusion criteria. A meta-analysis was conducted when the studies had comparable outcomes, inclusion criteria, and follow-up. There was reasonably clear evidence in favor of the stapled procedure for bleeding at 2 weeks (relative risk, 0.55; 95% confidence interval, 0.37-0.82) and length of hospital stay (weighted mean difference, -0.89 days; 95% confidence interval, -1.42 to -0.36). Other less robust results in favor of the stapled hemorrhoidectomy related to pain, bleeding, anal discharge, wound healing, tenderness to per rectal examination, incontinence scores, earlier return of bowel function, analgesic requirement, and resumption of normal activities. One trial showed that prolapse occurred at significantly higher rates in the stapled hemorrhoidectomy group. However, the outcomes were poorly reported and generally showed statistically significant heterogeneity. CONCLUSIONS: Stapled hemorrhoidectomy may be at least as safe as conventional hemorrhoidal surgical techniques. However, the efficacy of the stapled procedure compared with the conventional techniques could not be determined. More rigorous studies with longer follow-up periods and larger sample sizes need to be conducted.
A number of different materials are available for incisional hernia repair. Benefits of the various types are controversial and are partly dependent on the anatomical placement of the mesh. Composite mesh has been introduced to provide tissue ingrowth for strength and a non-adherent side to protect the bowel, these layers being laminated together. This report is on the separation of layers in an infected mesh and adherence of the expanded polytetrafluoroethylene layer to the small bowel.
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The safety and efficacy of off-pump coronary artery bypass surgery with the aid of the Octopus Tissue Stabilizer (Octopus OPCAB), in comparison to conventional on-pump coronary artery bypass surgery (CPB-CABG), was examined by a systematic assessment of the peer-reviewed literature. The limited comparative data suggested that there was no difference in safety outcomes between Octopus OPCAB and CPB-CABG. The paucity of efficacy data reported in the higher level comparative studies meant that it was impossible to assess whether Octopus OPCAB was more efficacious than CPB-CABG. The evidence base for the procedure was deemed inadequate and an audit of the procedure was recommended.
BACKGROUND: The aim of this systematic review was to compare the safety and efficacy of dynamic graciloplasty with colostomy for the treatment of faecal incontinence. METHODS: Two search strategies were devised to retrieve literature from the Medline, Current Contents, Embase and Cochrane Library databases up until November 1999. Inclusion of papers depended on a predetermined protocol, independent assessments by two reviewers and a final consensus decision. English language papers were selected. Acceptable study designs included randomized controlled trials, controlled clinical trials and case series. Forty papers met the inclusion criteria. They were tabulated and critically appraised in terms of methodology and design, outcomes, and the possible influence of bias, confounding and chance. RESULTS: No high-level evidence was available and there were no comparative studies. Mortality rates were around 2 per cent for both graciloplasty and colostomy. Morbidity rates reported for graciloplasty appear to be higher than those for colostomy. Dynamic graciloplasty was clearly effective at restoring continence in between 42 and 85 per cent of patients, whereas colostomy is, by its design, incapable of restoring continence. However, dynamic graciloplasty is associated with a significant risk of reoperation. CONCLUSION: While dynamic graciloplasty appears to be associated with a higher rate of complications than colostomy, it is clearly a superior intervention for restoring continence in some patients. It is recommended that a comparative, but non-randomized, study be undertaken to evaluate the safety of dynamic graciloplasty in comparison to colostomy, and that the procedure should be performed only in centres where it is carried out routinely.