An in vitro study assessing the effect of mesh morphology and suture fixation on bacterial adherence.

PURPOSE: Prosthetic infections, although relatively uncommon in hernia surgery, are a source of considerable morbidity and cost. The aims of this experimental study were to assess the influence of the morphological properties of the mesh on bacterial adherence in vitro. The morphological properties assessed were the polymer type, filament type, filament diameter, mesh weight, mean pore size, and the addition of silver chlorhexidine and titanium coatings. In addition, the study assessed the effect on bacterial adherence of adding a commonly used suture to the mesh and compared adherence rates to self-gripping mesh that does not require suture fixation. METHODS: Eight commercially sourced flat hernia meshes with different material characteristics were included in the study. These were Prolene(®) (Ethicon(®)), DualMesh(®) (Gore(®)), DualMesh(®) Plus (Gore(®)), Parietex™ ProGrip (Covidien™), TiMesh(®) Light (GfE Medical), Bard(®) Soft Mesh (Bard(®)), Vypro(®) (Ethicon(®)), and Omyra(®) (Braun(®)). Individual meshes were inoculated with Staphylococcus epidermidis and Staphylococcus aureus with a bacterial inoculum of 10(2) bacteria. To assess the effect of suture material on bacterial adhesion, a sterile piece of commonly used monofilament suture material (2.0 Prolene(®), ZB370 Ethicon(®)) was sutured to selected meshes (chosen to represent different commonly used polymers and/or the presence of an antibacterial coating). Inoculated meshes were incubated for 18 h in tryptone soy broth and then analysed using scanning electron microscopy. A previously validated method for enumeration of bacteria using automated stage movement electron microscopy was used for direct bacterial counting. The final fraction of the bacteria adherent to the mesh was compared between the meshes and for each morphological variable. One-way analysis of variance (ANOVA) was performed on the bacterial counts. Tukey's test was used to determine the difference between the different biomaterials in the event the ANOVA was significant. RESULTS: Properties that significantly increased the mean bacterial adherence were the expanded polytetrafluoroethylene polymer (P < 0.001); multifilament meshes (P < 0.001); increased filament diameter (P < 0.001); increased mesh weight (P < 0.001); and smaller mean pore size (P < 0.001). In contrast, mesh coating with antibacterial silver chlorhexidine significantly reduced bacterial adhesion (S. epidermidis mean bacterial count 140.7 ± 19.1 SE with DualMesh(®) vs. 2.3 ± 1.2 SE with DualMesh(®) Plus, P < 0.001; S. aureus mean bacterial count 371.7 ± 22.7 SE with DualMesh(®) vs. 19.3 ± 4.7 SE with DualMesh(®) Plus, P = 0.002). The addition of 2.0 Prolene suture material significantly increased the mean number of adherent bacteria independent of the mesh polymer or mesh coating (P = 0.04 to <0.001). CONCLUSION: The present study demonstrates the significant influence of the prosthetic load on bacterial adherence. In patients at increased risk of infection, low prosthetic load materials, i.e., lightweight meshes with large pores, may be beneficial. Furthermore self-fixing meshes, which avoid increasing the prosthetic load and antibacterial impregnated meshes, may have an advantage in this setting.

Radioactive seed embolization to the lung following prostate brachytherapy.

Over the past decade, prostate brachytherapy has been increasingly utilized as definitive management for early stage carcinoma of the prostate gland. One risk of the procedure is pulmonary seed embolization. In this article we report the incidence and timing of seed migration. Pulmonary embolization of radioactive seeds occurs in approximately 20% of patients undergoing prostate brachytherapy. To date, no acute or delayed detrimental effects have been reported which are attributable to the pulmonary embolization of the seeds; nevertheless, it is imperative that patients and health care providers be cognizant of this possible event.

The role of urinary assessment scores in the nursing management of patients receiving prostate brachytherapy.

Nearly all patients experience some degree of urinary irritative or obstructive symptoms following brachytherapy for definitive treatment of early-stage prostate cancer. The American Urological Association (AUA) Symptom Index is a tool developed to measure urinary function and can be incorporated into postoperative nursing management. When this questionnaire is administered at regular intervals following surgery, the patient's urinary status can be assessed quickly and treatment changes made according to symptoms, with resultant improvement in comfort levels. The postoperative use of the AUA index is recommended for all nurses who care for patients undergoing prostate brachytherapy.

Dextran 70 in prophylaxis of postoperative venous thrombosis. A controlled trial.

A controlled prospective trial was carried out in a group of 80 women undergoing gynaecological surgery and thought to be at risk of developing postoperative venous thrombosis. The patients, who had been randomly allocated to prophylaxis with either dextran 70 or warfarin, were well matched in age, weight and other predisposing factors.In the warfarin group, 12 out of 40 patients developed deep vein thrombosis, six of these episodes being classified as major and six as minor. In the dextran 70 group, 4 out of 40 patients developed deep vein thrombosis, all of them minor. The protective effect of dextran 70 is significantly better than that of warfarin (P<0.01) as used in the present study.

Diagnostic accuracy in venous thrombosis.

A group of 111 surgical patients at high risk of venous thrombosis were studied after operation by independent clinical assessment and with (125)I-fibrinogen to detect venous thrombosis. Almost half of the patients developed venous thrombosis. Of these, two-thirds were not suspected clinically despite careful scrutiny. In the patients in whom a clinical diagnosis of venous thrombosis was made this diagnosis was falsely positive in a quarter. More than half of all thrombotic episodes were detectable on the day after operation.The prevalence of venous thrombosis, together with the difficulty in diagnosing it, strongly supports the argument that a reduction in the incidence of pulmonary embolism must depend on widespread adoption of effective prophylaxis, especially in the large number of patients at high risk of venous thrombosis. Prophylactic trials must be objectively assessed, and it is in this field that the (125)I-fibrinogen technique probably has the most to offer.