Are late hernia mesh complications linked to Staphylococci biofilms?

PURPOSE: The purpose of this study was to investigate the link between bacterial biofilms and negative outcomes of hernia repair surgery. As biofilms are known to play a role in mesh-related infections, we investigated the presence of biofilms on hernia meshes, which had to be explanted due to mesh failure without showing signs of bacterial infection. METHODS: In this retrospective observational study, 20 paraffin-embedded tissue sections from explanted groin hernia meshes were analysed. Meshes have been removed due to chronic pain, hernia recurrence or mesh shrinkage. The presence and bacterial composition of biofilms were determined. First, specimens were stained with fluorescence in situ hybridisation (FISH) probes, specific for Staphylococcus aureus and coagulase-negative staphylococci, and visualised by confocal laser scanning microscopy. Second, DNA was extracted from tissue and identified by S. aureus and S. epidermidis specific PCR. RESULTS: Confocal microscopy showed evidence of bacterial biofilms on meshes in 15/20 (75.0%) samples, of which 3 were positive for S. aureus, 3 for coagulase-negative staphylococci and 9 for both species. PCR analysis identified biofilms in 17/20 (85.0%) samples, of which 4 were positive for S. aureus, 4 for S. epidermidis and 9 for both species. Combined results from FISH/microscopy and PCR identified staphylococci biofilms in 19/20 (95.0%) mesh samples. Only 1 (5.0%) mesh sample was negative for bacterial biofilm by both techniques. CONCLUSION: Results suggest that staphylococci biofilms may be associated with hernia repair failure. A silent, undetected biofilm infection could contribute to mesh complications, chronic pain and exacerbation of disease.

Biofilms and effective porosity of hernia mesh: are they silent assassins?

PURPOSE: The purpose of this paper is to communicate two new concepts with the potential to cause major morbidity in hernia repair, effective porosity and biofilm. These 2 concepts are interrelated and have the potential to result in mesh-related complications. Effective porosity is a term well described in the textile industry. It is best defined as the changes to pore morphology after implantation of mesh in situ. It is heavily dependent on mesh construct and repair technique and has the potential to impact hernia repair by reducing mesh tissue integration and promoting fibrosis. Bacterial biofilm is a well-described condition affecting prosthesis in breast and join replacement surgery with catastrophic consequences. There is a paucity of information on bacterial biofilm in mesh hernia repair. We speculate that bacterial biofilm has the potential to reduce the effective porosity of mesh, resulting in non-suppurative mesh-related complications as well as the potential for late suppurative infections. We describe the aetiology, pathogenesis, diagnosis, treatment and preventative measures to address bacterial biofilm in mesh hernia surgery. Hernia surgeons should be familiar with these two new concepts which have the potential to cause major morbidity in hernia repair and know how to address them. METHODS: Ovid Medline and PubMed were searched for communications on "effective porosity" and "bacterial biofilm". RESULTS: There is a paucity of information in the literature of these conditions and their impact on outcomes following mesh hernia repair. CONCLUSIONS: We discuss the two concepts of effective porosity and biofilm and propose potential measures to reduce mesh-related complications. This includes choosing mesh with superior mesh construct and technical nuances in implanting mesh to improve effective porosity. Furthermore, measures to reduce bacterial biofilm and its consequences are suggested.

Effect of preoperative two-dimensional animation information on perioperative anxiety and knowledge retention in patients undergoing bowel surgery: a randomized pilot study.

AIM: The use of multimedia information provided preoperatively can potentially reduce anxiety in patients and improve the hospital experience. However, the use of two-dimensional (2D) animation (cartoon) to provide information to patients undergoing colorectal surgery has not been investigated. This study investigated the effect of preoperative 2D information on anxiety and knowledge retention in patients undergoing bowel surgery. METHOD: Patients were randomized to one of two groups; the video group watched a 13-min cartoon animation whereas the nonvideo group did not. Anxiety levels were measured at the preadmission clinic, postvideo, on the day of admission for surgery, within 24-h after surgery and before discharge using the Spielberger state-trait anxiety inventory and visual analogue scale. Both groups completed a knowledge retention questionnaire and the video group completed a feedback questionnaire about the animation. RESULTS: Thirty-one patients (16 video, 15 nonvideo) participated in the study. There was no significant difference in baseline anxiety score between two groups. An immediate reduction (P = 0.03) in anxiety score was observed in the video group after watching the video compared with baseline. There was a significant reduction in anxiety score in the video group at discharge compared with the nonvideo group (P = 0.03). There was no significant difference in knowledge retention between two groups. Eighty-eight per cent of patients who watched the video found it beneficial. CONCLUSION: 2D animation is an effective medium for delivering information to patients undergoing bowel surgery and can potentially reduce anxiety related to surgery and improve the hospital experience.

Hypothermia induced by laparoscopic insufflation. A randomized study in a pig model.

Hypothermia is a common postsurgical problem, yet information documenting the impact of laparoscopy on perioperative heat balance is scarce. This paper quantifies the changes in core temperature over a 3-h period of high-flow CO2 insufflation in a randomized, controlled trial of six pigs. Each animal was anesthetized and studied on three occasions under standardized conditions, acting as its own control via insufflation with no gas compared with insufflation by cold gas and warmed gas. Insufflation of CO2 gas at high-flow rates over a prolonged period of time results in a significant fall in core temperature. The provision of warmed rather than cold insufflated gas confers no protection against changes in core temperature during laparoscopic surgery due to the small amount of heat required to warm the gas to body temperature. A much greater effect is the latent heat required to saturate the insufflated gas. Most of the hypothermic effect is due to this, and could be minimized by humidifying the flow.

Intestinal ischaemia associated with carcinoid tumour: a case report with review of the pathogenesis.

A case of ischaemic ileal perforation associated with a macroscopically unapparent ileal carcinoid is described. The mesenteric vessels were non-pulsatile at operation but were anatomically patent when examined by the pathologist. The characteristic elastic perivascular sclerosis of mesenteric vessels, which probably caused a functional vascular obstruction, was only discovered after the histological sections were reviewed. The true incidence of this rare condition may be higher than previously suspected because the perivascular sclerosis can easily be overlooked. Awareness of the association between carcinoid tumour and mesenteric ischaemia may lead to early surgery and an improved outcome.

Intestinal passage of the PEG end-piece: is it safe?

Two rare but life-threatening complications of percutaneous endoscopic gastrostomy (PEG) are reported: small bowel perforation and obstruction. Both resulted from impaction of the PEG end-piece after separation at skin level. Review of the literature revealed very few complications from intestinal passage of PEG end-pieces. The free intragastric PEG end-piece routinely passes through the gastrointestinal tract in most cases. One of these two cases was drawn from a series of 100 patients with intentional intestinal passage of PEG end-pieces to give a severe complication rate of 1%. A case can be made for routine endoscopic per-oral removal of PEG end-pieces in the elective setting, but this is more costly and not without hazard. Previous laparotomy and/or known adhesions is a relative indication for endoscopic retrieval of the PEG end-piece. Oesophageal disease or intolerance of endoscopy is a relative indication for intestinal passage. Close clinical follow up is recommended to ensure that the PEG end-piece has passed per-rectum. If the PEG end-piece has not passed and is shown in the small bowel on plain X-ray at approximately 3 weeks after separation then lodgement has probably occurred and early operative intervention is warranted.

The relationship between regional blood flow and absorption of lignocaine.

With the increasing application of certain surgical procedures to 'day surgery' cases, there has been greater utilization of local anaesthetic agents. Such procedures are undertaken using single infiltration dosage recommendations for lignocaine, both with and without adrenaline. The present paper describes results obtained from a sheep model that considers the role of the regional blood flow of the injected site as a determinant of lignocaine absorption and resultant pharmacokinetics. The peak concentration of lignocaine in plasma following administration to two selected sites of different vascularity (as determined by a technetium99 washout method), as well as the effect of concomitant adrenaline administration, was shown to correlate with the regional blood flow to the site (rs = 0.73, P = 0.008). Extrapolating these animal data to the clinical situation suggests that larger dosages of lignocaine could be used safely for infiltration anaesthesia in regions of poor regional blood flow without posing a threat of lignocaine-induced toxicity, and that the current dosage recommendations could be modified in respect of the regional blood flow of the particular site to be infiltrated.

Regional blood flow as a determinant of drug absorption description of an animal model.

Factors that influence recommended dosage guidelines for intramuscularly and subcutaneously injected drugs include a spectrum of variables, including therapeutic objective(s), the drug's therapeutic index, the inclusion of concomitant vasoconstrictors, and so on. However, little account is taken of the likely influence of regional blood flow at the injection site. This may vary according to the site of injection, the age and medical condition of the patient with the potential to markedly affect the rate of drug absorption and the resultant therapeutic and toxicity outcomes. An animal model is described for simultaneously quantifying the drug's pharmacokinetic profile and the regional blood flow (using technetium99 elution) at sites of differing vascularity so that the potential relationship can be ascertained. An application to lignocaine absorption is provided, however, the model would be applicable to a range of drug applications and could serve as a means of investigating differences both within a drug class (e.g., members with differing lipophilicity) as well as across drug classes (e.g., local anesthetics, opiates, insulin preparations, etc.).

Evaluation of the safety of inguinal hernia repair in the elderly using lignocaine infiltration anaesthesia.

Repair of inguinal hernia using local anaesthesia is becoming increasingly popular as it avoids many of the systemic side effects associated with general or spinal/epidural anaesthesia and provides excellent early postoperative pain relief. Dosages of local anaesthetic approaching the recommended maximum are frequently required for adequate anaesthesia of the inguinal region. The present study describes the disposition and safety of lignocaine with adrenaline in 14 elderly patients to ascertain its safety with a view to more widespread application of the technique in more complicated hernia repairs. Serial plasma lignocaine concentrations were determined for up to 24 h following doses approaching the recommended maximum for infiltration (7 mg/kg). Peak lignocaine concentrations (normalized to 7 mg/kg) ranged from 0.23 to 0.90 mg/L (mean of 0.54 mg/L); that is, the maximum recorded concentration was less than one-fifth the toxicity threshold for lignocaine of 5 mg/L. The study suggested that the majority of patients tolerated the local anaesthetic approach very well and that the wide safety margin allowed ample scope to develop the local anaesthetic approach for the repair of more complex hernia repairs (e.g. large, bilateral or strangulated herniae, or those in obese patients) without risk of exposing patients to lignocaine concentrations which may cause toxic side effects.

A safe, new approach to establishing a pneumoperitoneum at laparoscopy.

The traditional method of establishing a pneumoperitoneum before laparoscopic surgery is via a Verres needle inserted in the midline below the umbilicus while tenting the abdominal wall with the hand. A new approach is described in which preliminary surgical exposure and tenting of the linea alba immediately above the umbilicus is achieved before needle insertion through the superior margin of the umbilical ring. The advantages of this new technique over the conventional method are discussed. Further technical features important in the safe formation of the pneumoperitoneum are emphasized.

Review of pyogenic liver abscess at the Royal Adelaide Hospital 1980-1987.

Pyogenic liver abscess is an uncommon condition which carries substantial morbidity and mortality if untreated. A review was undertaken of 31 patients who were admitted to the Royal Adelaide Hospital (RAH) between January 1980 and December 1987 and who were diagnosed as having pyogenic liver abscess. The aims of the study were to review the aetiology, current methods of investigation and treatment of the disease, and to formulate a management plan based on the findings. Hypoalbuminaemia, leukocytosis and elevated alkaline phosphatase were the most common findings. Hyperbilirubinaemia was not a usual feature. Computerised tomography (CT) scanning and ultrasound were the most useful imaging modalities in identification of the abscess. The sensitivity of CT scanning in evaluating the size of abscesses was lower than anticipated and this may lead to a higher than necessary rate of surgical drainage. A case is presented to illustrate this. Most abscesses were secondary and frequently due to extension of infection from biliary structures. Diseases causing diminished resistance to bacterial infection had a significant role in the pathogenesis. The overall mortality rate was 25%. Risk factors increasing mortality included advanced age, multiplicity of abscesses, depressed immune status and the presence of complications due to the abscess. Of patients who survived, four were treated with antibiotics alone, eleven with percutaneous drainage and antibiotics, and eight with surgery and antibiotics. We conclude that patients with hepatic abscesses should be managed initially by CT or ultrasound-guided aspiration. If pus is obtained a percutaneous drain should be inserted into the cavity and systemic antibiotics administered.(ABSTRACT TRUNCATED AT 250 WORDS)