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.

Seven years of preoperative BTA abdominal wall preparation and the Macquarie system for surgical management of complex ventral hernia.

PURPOSE: To assess 7-year outcomes after complex ventral hernia (CVH) repair using pre-operative Botulinum toxin A (BTA) injection and the Macquarie System of management. METHODS: Clinical examination and functional non-contrast abdominal CT scans were used to assess complications and recurrences encountered in a prospective series of 88 consecutive CVH repairs using pre-operative BTA injection (200 or 300 units) between November 2012 and December 2019. Pre-operative progressive pneumoperitoneum (PPP) and/or component separation (CS) were also used in some cases. RESULTS: All hernia defects (mean transverse width 12.9 ± 5.2 cm) were successfully closed using either laparoscopic or laparoscopic-assisted open techniques facilitated by pre-operative BTA injection. The mean pre-operative post-BTA lateral oblique length gain was 4.7 ± 2.2 cm/side (p < 0.001). In 43 patients with defects < 12 cm wide, closure was achieved using BTA-only in 33 (76.7%), BTA + PPP in 2 (4.7%), BTA + CS in 5 (11.6%) and BTA + PPP + CS in 3 (7.0%). In the remaining 45 patients with defects [Formula: see text] 12 cm wide, closure was achieved using BTA-only in 9 (20.0%), BTA + PPP in 11 (24.4%), BTA + CS in 5 (11.1%) and BTA + PPP + CS in 20 (44.4%). There was a significant correlation between increasing defect size and the need for 2 or more CVH closure procedures (χ2 = 25.28, p < 0.0005). There were no BTA complications. Two patients developed midline hernia recurrences. CONCLUSION: Pre-operative BTA injection of the abdominal wall is a safe procedure that facilitates hernia defect closure and reduces the need for CS, especially when defect size is less than 12 cm. BTA may also decrease the rate of hernia recurrence.

Selective muscle botulinum toxin A component paralysis in complex ventral hernia repair.

INTRODUCTION: Repair of complex ventral hernia presents a significant challenge plagued by high morbidity and recurrence. Recent studies have demonstrated significant benefits achievable with preoperative Botulinum Toxin A (BTA) chemical component paralysis to the abdominal wall muscles, facilitating primary closure of complex ventral hernia defects. However, transversus abdominis is known to play an integral role in truncal stability, and its paralysis can result in unwanted physiological changes. This is the first study to report on selective administration of preoperative BTA to internal and external oblique muscles only, thus sparing transversus abdominis from paralysis. METHODS: This is a prospective observational study of 46 patients who underwent either selective two-layer or standard three-layer abdominal wall muscle BTA injection prior to elective laparoscopic ventral hernia repair. Serial abdominal CT imaging was performed to compare defect size and length of the lateral abdominal musculature. RESULTS: 46 patients received preoperative BTA injections (23 in each group). A comparison of gains achieved from chemical component paralysis demonstrated no statistically significant difference between the two groups. Fascial closure was achieved in all cases, with no post-operative sequelae of abdominal hypertension. There are no hernia recurrences to date. CONCLUSION: Preoperative selective muscle chemical component paralysis is an effective technique to counteract the chronic muscle retraction observed in large ventral hernias. Transversus abdominis plays a significant role in truncal and spinal stability, and sparing it from paralysis preserves an important component of abdominal wall physiology and does not detract from the ability to primarily close complex defects.

The macquarie system for comprehensive management of complex ventral hernia.

BACKGROUND: Despite recent advances in the operative management of complex ventral hernia (CVH), significant challenges remain. Closure of large defects can have serious pathophysiological consequences due to chronic contraction and retraction of the lateral abdominal wall muscles. Certain features of CVH make repair technically demanding and time consuming, such as massive fascial defects, unusual hernia locations, involvement of other abdominal wall structures and previous tissue trauma. METHODS: Preoperative assessment with three-dimensional volume rendered CT (3DVR-CT) imaging and an illustrative series of clinical cases is introduced for repair of CVH using laparoscopic approach. RESULTS: CVH presented here include traumatic hernias involving extensive tissue trauma, massive ventral hernias with defects > 20 cm in width, hernias requiring additional procedures such as wiring of ribs, and hernias in difficult locations such as suprapubic and flank hernias. Specific techniques such as individually tailoring mesh and size, transfascial mesh straps fixation and transcutaneous defect closure will be discussed. All hernias in this series have been repaired laparoscopically (Lap) or laparoscopic-open-laparoscopic (LOL) technique with transcutaneous fascial closure. After hernia closure the mesh is placed in either an intra-peritoneal onlay mesh (IPOM) placement or modified Rives-Stoppa technique with pre-peritoneal mesh placement. CONCLUSION: CVH repair requires multidisciplinary planning with management tailored to each patient's clinical and surgical requirements. The surgeon must have a variety of surgical skills and strategies to address the multiple and/or atypical defects that affect these patients.

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.

Laparoscopic repair of complex ventral hernia facilitated by pre-operative chemical component relaxation using Botulinum Toxin A.

PURPOSE: The operative management of complex ventral hernia poses a formidable challenge, despite recent advances in surgical techniques. Recurrence rates after complex ventral hernia repair remain high, and increase with each failed attempt. This study examines the effect of pre-operative abdominal wall chemical component relaxation using Botulinum Toxin A (BTA) to induce temporary flaccid paralysis in order to facilitate laparoscopic repair of large complex ventral hernia. METHODS: This is a prospective evaluation of 27 patients from January 2013 to August 2015 who underwent ultrasound guided BTA injections to the lateral abdominal wall muscles prior to elective complex ventral hernia repair. Non-contrast serial CT imaging was obtained pre- and post-BTA injection to measure change in fascial defect size and abdominal wall muscle thickness and length. Fascial defects were closed and hernias repaired using laparoscopic or laparoscopic-assisted intra-peritoneal onlay mesh (IPOM) techniques. RESULTS: 27 patients received pre-operative BTA injections which were well tolerated with no complications. Comparison of pre-BTA and post-BTA CT imaging demonstrated a significant increase in mean length of the lateral abdominal wall from 15.7 cm pre-BTA to 19.9 cm post-BTA (p < 0.0001), with mean unstretched length gain of 4.2 cm/side (range 0-11.7 cm/side). All hernias were surgically reduced and repaired with mesh, with no early recurrences. CONCLUSION: Pre-operative administration of BTA is a safe and effective technique in the pre-operative preparation of patients undergoing elective complex ventral hernia repair. This technique lengthens and relaxes the laterally retracted abdominal muscles and enables laparoscopic closure of large complex ventral hernia.

Intensive care unit environmental surfaces are contaminated by multidrug-resistant bacteria in biofilms: combined results of conventional culture, pyrosequencing, scanning electron microscopy, and confocal laser microscopy.

BACKGROUND: Hospital-associated infections cause considerable morbidity and mortality, and are expensive to treat. Organisms causing these infections can be sourced from the inanimate environment around a patient. Could the difficulty in eradicating these organisms from the environment be because they reside in dry surface biofilms? AIM: The intensive care unit (ICU) of a tertiary referral hospital was decommissioned and the opportunity to destructively sample clinical surfaces was taken in order to investigate whether multidrug-resistant organisms (MDROs) had survived the decommissioning process and whether they were present in biofilms. METHODS: The ICU had two 'terminal cleans' with 500 ppm free chlorine solution; items from bedding, surrounds, and furnishings were then sampled with cutting implements. Sections were sonicated in tryptone soya broth and inoculated on to chromogenic plates to demonstrate MDROs, which were confirmed with the Vitek2 system. Genomic DNA was extracted directly from ICU samples, and subjected to polymerase chain reaction (PCR) for femA to detect Staphylococcus aureus and the microbiome by bacterial tag-encoded FLX amplicon pyrosequencing. Confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) were performed on environmental samples. FINDINGS: Multidrug-resistant bacteria were cultured from 52% (23/44) of samples cultured. S. aureus PCR was positive in 50%. Biofilm was demonstrated in 93% (41/44) of samples by CLSM and/or SEM. Pyrosequencing demonstrated that the biofilms were polymicrobial and contained species that had multidrug-resistant strains. CONCLUSION: Dry surface biofilms containing MDROs are found on ICU surfaces despite terminal cleaning with chlorine solution. How these arise and how they might be removed requires further study.

Assessment of the selection process for myocutaneous flap repair and surgical complications in pelvic exenteration surgery.

BACKGROUND: This study aimed to explore and quantify the selection process to guide the decision on closure type (myocutaneous flap repair (MFR) or primary closure) for people undergoing pelvic exenteration. METHODS: This was a retrospective analysis of a prospectively maintained database with review of hospital records for verification and capture of missing data. Associations between four risk factors (previous radiotherapy, previous abdominoperineal resection, need for total exenteration, need for sacrectomy) were assessed individually and collectively as predictors of closure type and wound complications. RESULTS: A total of 203 pelvic exenteration procedures were reviewed (75 primary and 122 recurrent cancers). Thirty-nine patients (19·2 per cent) had MFR and 164 (80·8 per cent) primary closure. Patients who had MFR were significantly more likely to exhibit each risk factor, confirming the selective decision process. MFR had higher rates of complications across all four risk factors, individually and combined. In the primary closure group, there was a significant correlation between the number of risk factors and the proportion of patients with a complication (r = 0·25, P = 0·008). In contrast, no such relationship was found for the MFR group (r = 0·01, P = 0·973). Among patients who had any complication, the primary closure group had significantly lower rates of any wound dehiscence (15 of 64 versus 17 of 28; P < 0·001) and total infection (16 of 64 versus 14 of 28; P = 0·019) compared with the MFR group. CONCLUSION: Rates of wound and septic complications after pelvic exenteration were low in patients with fewer than two risk factors who had a primary closure. MFR had significantly higher complication rates, and should be reserved for patients with two or more risk factors or extensive skin involvement.

Presence of biofilm containing viable multiresistant organisms despite terminal cleaning on clinical surfaces in an intensive care unit.

BACKGROUND: Despite recent attention to surface cleaning and hand hygiene programmes, multiresistant organisms (MROs) continue to be isolated from the hospital environment. Biofilms, consisting of bacteria embedded in exopolymeric substances (EPS) are difficult to remove due to their increased resistance to detergents and disinfectants, and periodically release free-swimming planktonic bacteria back into the environment which may may act as an infection source. AIM: To establish whether reservoirs of MROs exist in the environment as biofilms. METHODS: Following terminal cleaning, equipment and furnishings were removed aseptically from an intensive care unit (ICU) and subjected to culture and scanning electron microscopy (SEM). Samples were placed in 5 mL of tryptone soya broth, sonicated for 5 min before plate culture on horse blood agar, Brillance MRSA and Brilliance VRE agar plates. Samples for SEM were fixed in 3% glutaraldehyde and hexamethyldisilizane (HMDS) prior to sputter-coating with gold and examination in an electron microscope. FINDINGS: Biofilm was demonstrated visually on the sterile supply bucket, the opaque plastic door, the venetian blind cord, and the sink rubber, whereas EPS alone was seen on the curtain. Viable bacteria were grown from three samples, including MRSA from the venetian blind cord and the curtain. CONCLUSION: Biofilm containing MROs persist on clinical surfaces from an ICU despite terminal cleaning, suggesting that current cleaning practices are inadequate to control biofilm development. The presence of MROs being protected within these biofilms may be the mechanism by which MROs persist within the hospital environment.

Pancreatic trauma in children.

BACKGROUND/PURPOSE: The aim of this study was to determine the etiology, associated injuries, and outcome of children with pancreatic injuries. METHODS: A retrospective review was conducted of children under 16 years with pancreatic trauma admitted to the Children's Hospital at Westmead (CHW) from January 1983 to September 2002. Deaths were reported to the New South Wales Paediatric Trauma Death Registry (State Registry) from January 1988 to September 2002. RESULTS: Sixty-five cases were identified: 46 patients were admitted to CHW, and 22 deaths were reported to the State Registry (including 3 deaths at CHW). The median age was 6 years (range, 1 to 14 years). Boys accounted for 60% (n = 40) of cases, decreasing to 50% (n = 11) of those that died. Motor vehicle injuries (MVI) were the most common mechanism, accounting for 40% of survivors and 77% of those who died. Children were restrained incorrectly in 48% of all cases and in 67% of those who died. Significantly more children who died had head, chest, and abdominal visceral injuries, compared with those who survived. Death occurred as a result of head injuries in 68%, with only 3 deaths directly attributed to pancreatico-duodenal injuries. CONCLUSIONS: Pancreatic injuries remain uncommon in children. The most frequent mechanism was MVI, with incorrect use of passenger restraints an important contributing factor. Whereas mortality was mainly caused by other injuries, 3 deaths were directly attributable to pancreato-duodenal trauma.

Single nucleotide primer extension (SNuPE) analysis of the G6PD gene in somatic cells and oocytes of a kangaroo (Macropus robustus).

cDNA sequence analysis of the X-linked glucose-6-phosphate dehydrogenase (G6PD) gene has shown a base difference between two subspecies of the kangaroo, Macropus robustus robustus (wallaroo) and M. r. erubescens (euro). A thymine residue in the wallaroo at position 358 in exon 5 has been replaced by a cytosine residue in the euro, which accounts for the previously reported electrophoretic difference between the two subspecies. This base difference allowed use of the Single Nucleotide Primer Extension (SNuPE) technique to study allele-specific expression of G6PD at the transcriptional level. We began by examining G6PD expression in somatic cells and observed complete paternal X inactivation in all somatic tissues of adult female heterozygotes, whereas we found partial paternal allele activity in cultured fibroblasts, thus confirming previous allozyme electrophoresis studies. In late dictyate oocytes from an adult heterozygote, the assay also detected expression of both the maternal and paternal alleles at the G6PD locus, with the maternal allele showing preferential expression. Thus reactivation of the inactive paternally derived X chromosome occurs during oogenesis in M. robustus, although the exact timing of reactivation remains to be determined.

Maternal caffeine consumption during pregnancy does not affect preimplantation development but delays early postimplantation growth in rat embryos.

Models for studying prenatal drug-induced intrauterine growth retardation (IUGR) have, without exception, measured growth-related factors in the postimplantation embryo, fetus or neonate. Therefore, it is not known whether effects of drug exposure on growth and metabolism begin early in the preimplantation embryo, or whether IUGR is exclusively a postimplantation phenomenon. The present study investigates whether caffeine, a drug known to induce a dose-dependent fetal IUGR, affects embryo development before and/or after implantation or is exclusively a fetal phenomenon. Preimplantation embryo assessment (with treatment from Days 2 to 4 of pregnancy) included glucose utilization, cell number evaluation and stage of development (morula to hatched blastocyst); whereas, postimplantation embryo assessment (treatment from Days 2 to 10, 10.5 or 11 of pregnancy) included somite number evaluation and extent of neural tube closure, as seen using scanning electron microscopy. Comparing control preimplantation embryos with those exposed to 30 and 60 mg kg(-1) caffeine did not reveal any effects of caffeine exposure, as assessed on Day 5 of gestation. However, postimplantation embryo development assessed on Day 12 of gestation revealed that caffeine exposure of 15 and 30 mg kg(-1) significantly reduced, at both dosage levels, somite number and the extent of neural tube closure. In addition, comparisons of control and experimental groups revealed that in the high-dose caffeine group the forebrain cavity was significantly enlarged and bounded by a reduced, irregularly aligned neuroepithelium. The findings suggest that IUGR is a phenomenon first identifiable during late postimplantation embryogenesis and continues in fetal life.