Effect of povidone iodine and hydrogen peroxide on fracture healing: a histomorphometric study on rats

A Preliminary Exploration of the Efficacy of Gentamicin Sponges in the Prevention and Treatment of Wound Infections

Purpose

This study aimed to construct drug-loading and drug-releasing quantitative equations for gentamicin sponges in addition to realizing a gentamicin sponge for wound infection prevention and treatment.

Methods

Sterile sponges were cut into pieces of 1×1 × 0.5 cm and immersed in 40, 16, 8, 4, 1.6, 0.8, or 0 mg/mL of gentamicin solution for 12, 24, 48, 96, or 120 h to evaluate their gentamicin loading. The sponges were subsequently immersed in the gentamicin solution of different concentrations for 48 h, air-dried, and then immersed in 10 mL of 0.9% physiological saline to evaluate the gentamicin release. Methicillin-sensitive Staphylococcus aureus (MSSA) and Pseudomonas aeruginosa were used to explore the sponges’ infection prevention scheme. In addition, a rat femur fracture with wound infection model was used to assess the infection treatment scheme.

Results

The antibacterial zone sizes of the sponges immersed in 40, 16, 8, 4, 1.6, and 0.8 mg/mL of the gentamicin solution were larger than those of the 0 mg/mL air-dried sponge, and the difference was statistically significant (p < 0.01, p < 0.01, p < 0.01, p < 0.01, p < 0.01, and p < 0.01, respectively). The rats in the 40, 16, and 8 mg/mL air-dried sponge groups had no wound suppuration in either the MSSA or P. aeruginosa rat infection models.

Conclusion

A quantified equation for the sponges’ gentamicin loading and release was achieved with high accuracy. Furthermore, we recommend the 40, 16, or 8 mg/mL air-dried sponge for the treatment of wounds with antibiotic-sensitive bacterial infections.

Immediate replacement of bone flap after craniotomy for empyema in children

PURPOSE

Optimal management of the bone flap after craniotomy for intracranial infection has not been well defined in the pediatric population. This study reviewed the outcomes of a single Canadian center where immediate replacement of the bone flap was standard practice.

METHODS

This is a retrospective study of all patients who underwent craniotomies for evacuation of epidural or subdural empyema at a single center from 1982 to 2018. Patients were identified using the prospective surgical database maintained by the Division of Pediatric Neurosurgery at BC Children's Hospital. Primary outcome was treatment failure, defined as reoperation at the site of initial surgery for removal of an infected bone flap or repeat drainage of empyema under the replaced bone flap. Secondary outcome was any reoperation for recurrent infection at any site.

RESULTS

Twenty-four patients met the inclusion criteria with a minimum of 3-month follow-up from the index intervention. Treatment failure occurred in four patients (17%), all of whom required repeat surgery for further drainage of pus underlying the bone flap. Mean time to repeat surgery was 13 days. Any reoperation for recurrent infection at any site occurred in three patients. Seven out of 24 patients required a second surgery to evacuate empyema (29.2%). Age, sex, epidural or subdural location, osteomyelitis, and bone flap wash were not associated with the primary outcome of treatment failure.

CONCLUSION

Immediate replacement of the bone flap in the surgical management of pediatric subdural or epidural empyema is reasonable. Replacing the flap at the time of first surgery avoids the morbidity and costs of a subsequent reconstructive operation.

The effect of different irrigation solutions on fracture healing in a rat femur fracture model

Objectives

This study aims to evaluate and compare radiological, biomechanical, histopathological, histomorphometric and immunohistochemical effects of povidone iodine (PVP-I), hydrogen peroxide (HPO) and chlorhexidine gluconate (CHG) on fracture healing in their minimum cytotoxic and most efficient concentrations.

Materials and methods

This experimental animal study, conducted between April 2018 and January 2019, included 48 male Sprague Dawley® rats (weighing 356 g; aging 9 weeks) which were randomly divided into four groups: control (saline), HPO, PVP-I and CHG. Rat model of femoral fracture was established and intramedullary fixation was applied. Solutions were applied to fracture region in determined concentration and time, and all subjects were sacrificed on Day 28. Extracted femurs were investigated radiologically by micro-computed tomography. Then, all groups were divided into two random groups to be evaluated biomechanically, histopathologically, histomorphometrically and immunohistochemically.

Results

In histopathological evaluation, inflammation score of CHG group was significantly lower than other groups, and inflammation score of PVP-I group was significantly lower than control and HPO groups (p<0.05). Biomechanically, flexural strength (σbend) (megapascal) values of CHG and control groups showed similar results, but there was no significant difference between all groups (p>0.05). In immunohistochemical localization of bone morphogenic protein (BMP)-4, osteoblast and chondroblast histoscores (H-scores) of HPO group were significantly lower than other groups, and chondroblast H-score in CHG group was lower than control and PVP-I groups (p<0.05). In immunohistochemical localization of BMP-7, osteoblast H-score was significantly higher in CHG group than other groups (p<0.05).

Conclusion

We determined that CHG 0.05% solution had no negative effect on the fourth week of fracture healing histopathologically, immunohistochemically and biomechanically, and is an alternative irrigative to normal saline.

The Use of Antiseptic Solutions in the Prevention and Management of Penile Prosthesis Infections: A Review of the Cytotoxic and Microbiological Effects of Common Irrigation Solutions

INTRODUCTION

The Mulcahy salvage fundamentally altered the management of penile prosthesis infections (PPI). Central to this procedure is a sequence of antiseptic irrigations that aims to remove and eradicate pathogenic microflora from the infected field, thus preparing for immediate reimplantation. The antiseptic solutions and their respective concentrations, however, have never been evaluated for efficacy.

AIM

This review critically examines 3 commonly used antiseptic irrigation solutions (povidone-iodine [PVI], hydrogen peroxide [H₂O₂], and chlorhexidine gluconate [CHG]) in terms of their antimicrobial activity, cytotoxicity, and clinical use.

METHODS

A PubMed literature review was performed on articles published between 2003 and 2018. Both preclinical as well as clinical studies from various surgical disciplines were included in this review.

MAIN OUTCOME MEASURE

The original salvage protocol selected for irrigation solutions at concentrations that are likely detrimental to native tissue.

RESULTS

All 3 agents demonstrate in vitro cytotoxic effects at subclinical concentrations, but H₂O₂ is associated with the most significant deleterious properties. It does not seem to broaden antimicrobial coverage beyond what is covered by PVI. Dilute PVI (0.35-3.5% with exposure time of at least 3 minutes) possesses the most robust clinical evidence as an intraoperative adjunct, reducing the incidence of postoperative infectious complications. chlorhexidine gluconate is a promising new agent but lacks clinical data.

CLINICAL IMPLICATION

Improvements in the salvage protocol are warranted based on current evidence. Careful selection of lavage solution and usage of the lowest necessary concentration will help achieve desired antimicrobial activity while avoiding native tissue cytotoxicity. Strength and limitation: The study is limited by its retrospective nature, and the heterogeneity of literature reviewed precluded a formal meta-analysis. Furthermore, future studies will need to address the roles of normal saline and antibiotic irrigations as intraoperative adjuncts for infection prevention.

CONCLUSION

Diluted PVI (0.35-3.5% for 3 minutes) may be beneficial in the prevention of PPI. Evidence supports its use both in the setting of primary implantation as well as salvage of infected hardware. An improved, evidence-based protocol may increase positive outcomes of urologic prosthetic surgery. Pan S, Rodriguez D, Thirumavalavan N, et al. The Use of Antiseptic Solutions in the Prevention and Management of Penile Prosthesis Infections: A Review of the Cytotoxic and Microbiological Effects of Common Irrigation Solutions. J Sex Med 2019;16:781-790.