Systematic review of ototoxic pre-surgical antiseptic preparations - what is the evidence?

Surgical site antiseptic preparations for otolaryngology - Head and neck surgery: A current review

OBJECTIVE

To review current literature and guidelines on antiseptic surgical site preparations for preventing surgical site infections with consideration of contraindications specific to head and neck surgery.

DATA SOURCES

PubMed/MEDLINE, clinicaltrials.gov, accessdata.fda.gov, Manufacturer websites.

REVIEW METHODS

A scoping review on the literature and clinical studies comparing the efficacy of different surgical site preparations. Studies were included if they were a randomized controlled trial (RCT) comparing at least two commonly used and available antiseptic preparations. Additionally, a compilation of warnings and contraindications from manufacturer labels and articles are included. Due to the lack of randomized controlled trials concerning antiseptic preparation use in head and neck surgery specifically, an additional search was executed for articles not limited to randomized controlled trials that compared different antiseptic preparation used in surgeries concerning the head and neck.

RESULTS

Of 56,983 resulting abstracts and 3798 of them being screened, 25 RCTs were included. These RCTs included a variety of surgeries including gastrointestinal, obstetric, gynecologic, orthopedic, and vascular procedures. When searching for abstracts concerning head and neck surgeries, 9 studies were found and included.

CONCLUSIONS

To reduce surgical site infections and avoid application in situations with contraindications, practicing surgeons need to be familiar with the existing literature regarding different surgical preparations and what warnings manufacturers have listed on the products. Optimal surgical site preparation for head and neck surgery is challenging as proximity to oxygen contraindicates newer alcohol-based options that are potentially flammable. We summarize evidence-based surgical site preparation for head and neck surgery.

Surgery for Otitis Media with Effusion: A Survey of Otolaryngologists Who Treat Children in Brazil

Introduction Myringotomy and ear tube placement (MTP) is the surgical treatment for otitis media with effusion (OME), and it is the most common surgery performed in children. Several guidelines have been developed to assist in the care of patients who become candidates for MTP.

Objectives To evaluate the practice of Brazilian otorhinolarynogologists when performing MTP according to the years of clinical experience. Secondarily, we also want to assess if their practice regarding MTP varied according to the percentage of children treated and the location of their practice.

Methods A 30-question survey was sent to otolaryngologists affiliated with the Brazilian Academy of Pediatric Otorhinolaryngology (Academia Brasileira de Otorrinolaringologia Pediátrica, ABOPe, in Portuguese) and/or the Scientific Department of Otorhinolaryngology of the Brazilian Society of Pediatrics (Sociedade Brasileira de Pediatria, SBP, in Portuguese). The questions included were carefully chosen to provide a profile about the practices adopted in the pre-, peri- and postoperative periods of MTP.

Results The questionnaire was sent to 208 otolaryngologists, and there were 124 (59.6%) respondents. Of those, 59.7% use antiseptics before surgery. Only 54 otolaryngologists, less than half of the subjects in this study (43.5%), always place a tube during the procedure. More physicians who practice in small cities recommend water precautions after MTP when compared to other physicians (p < 0.001).

Conclusion The present study reveals that many respondents do not follow some of the recommendations of the current guidelines of the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) on OME, either perioperatively and postoperatively, or regarding the option of placing a ventilation tube. This part of the care also varied depending on the respondents' work location and experience in the medical practice.

Does Hypochlorous Acid Cause Ototoxicity? An Experimental Study

AIM

Hypochlorous acid (HOCl) is a weak acid that ionizes in water. It is an effective antiseptic exhibiting low toxicity on living tissues. We aimed to investigate the ototoxic effects of HOCl on an animal model by using electrophysiological and histological methods.

MATERIALS AND METHODS

The study comprised 32 Sprague-Dawley rats, which were separated into four groups: control group (A), saline solution group (B), 70% isopropyl alcohol + 2% chlorhexidine group (C), and HOCl group (D). After recording the auditory brainstem response (ABR) for basal hearing thresholds (8, 16, 24, and 32 kHz), 0.03 ml of the aforementioned materials was injected intratympanically three times every 2 days in groups B, C, and D. ABR measurements were repeated on the 7th and 21st days. All animals were sacrificed, and temporal bones were prepared for examinations of cochlear histology and vascular endothelial growth factor immunohistochemistry.

RESULTS

Basal hearing levels were normal across all frequencies and groups, with no statistical differentiation. On the 7th and 21st days after the ABR test, all other groups demonstrated a significant deterioration in hearing levels compared with group A. When the results from 7th and 21st days were compared within group D, a partial recovery was observed. In histopathology, groups C and D demonstrated moderate and severe cochlear degeneration, along with decreased immunoreactivity in the organ of Corti, stria vascularis, and spiral ligament.

CONCLUSION

This is the first study to evaluate the safety of using HOCl in otology. Although HOCI is less ototoxic than the disinfectant used, it may have a toxic effect on cochlea.Level of Evidence: Animal Research.

Povidone-Iodine Fails to Eradicate Chronic Suppurative Otitis Media and Demonstrates Ototoxic Risk in Mice

HYPOTHESIS

Commercially available povidone-iodine solution can eliminate biofilms and persister cells rapidly in in vivo achievable concentrations without inducing ototoxicity.

BACKGROUND

Chronic suppurative otitis media (CSOM) is a substantial global problem. Current treatment options often induce a temporary remission without leading to a permanent cessation of symptoms secondary to the treatments' inability to eliminate persister cells. Povidone-iodine has been shown to be able to clear biofilm and planktonic cells in in vitro assays, but there are reports of ototoxic effects limiting its clinical utility.

METHODS

Bacterial and biofilm growth with quantification by spectrophotomer, murine auditory brainstem response (ABR), and distortion product otoacoustic emissions, immunohistochemistry, in vivo povidone-iodine treatment of murine CSOM, persister cell assay.

RESULTS

Commercially available 10% povidone-iodine solution is able to completely eradicate multiple clinical strains of Pseudomonas aeruginosa and Staphylococcus aureus in vitro with 10 minutes of exposure. Mice that have received a transtympanic injection of 1% povidone-iodine solution did not have significantly different auditory brainstem response or distortion product otoacoustic emission results compared with the control. Mice that received a povidone-iodine scrub or 10% povidone-iodine solution had significantly worsened hearing (25- and 13-dB increase in threshold, respectively; p < 0.05). In vivo CSOM infection recurred in all mice after the completion of treatment with 10% povidone-iodine solution, and there was no improvement in the bacterial load after treatment, indicating in vivo failure of therapy.

CONCLUSION

Povidone-iodine solution is effective at eliminating biofilm and persister cells in vitro at in vivo achievable concentrations but fails in vivo most likely because of kinetics of distribution in vivo. Even if drug distribution could be improved, the therapeutic window is likely to be too small given that the diluted solution does not have ototoxic potential, whereas while the scrub variant, which contains detergents, and the undiluted solution are ototoxic after a single treatment.

Topical Therapy Failure in Chronic Suppurative Otitis Media is Due to Persister Cells in Biofilms

OBJECTIVE

Chronic suppurative otitis media (CSOM) is characterized by a chronically draining middle ear. CSOM is typically treated with multiple courses of antibiotics or antiseptics which are successful in achieving quiescence; however, the disease is prone to relapse. Understanding why these treatment failures occur is essential.

STUDY DESIGN

The minimum inhibitory concentration (MIC), minimal biofilm eradication concentration, and the inhibitory zone were determined for ototopicals and ofloxacin for the laboratory strains and CSOM-derived isolates. The percentage of persister cells and bacterial biofilm formation were measured. Disease eradication was tested in a validated in-vivo model of CSOM after treatment with ofloxacin.

SETTING

Microbiology Laboratory.

METHODS

Basic science experiments were performed to measure the effectiveness of a number of compounds against CSOM bacteria in a number of distinct settings.

RESULTS

The minimal biofilm eradication concentration is higher than is physiologically achievable with commercial preparations, except for povo-iodine. Clincial isolates of CSOM have equivalent biofilm-forming ability but increased proportions of persister cells. Ofloxacin can convert to inactive disease temporarily but fails to eradicate disease in an in-vivo model.

CONCLUSIONS

Higher percentages of persister cells in clinical CSOM isolates are associated with resistance to ototopicals. Current ototopicals, except povo-iodine, have limited clinical effectiveness; however, it is unknown what the maximum achievable concentration is and there are ototoxicity concerns. Fluoroquinolones, while successful in producing inactive disease in the short term, have the potential to encourage antimicrobial resistance and disease recalcitrance and do not achieve a permanent remission. Given these limitations, clinicians should consider surgery earlier or use of clinically safe concentrations of povo-iodine earlier into the treatment algorithm.

The safety of povidone-iodine solution in tympanoplasty: a randomised, triple-blind, placebo-controlled study

Objective

Nowadays, povidone-iodine is commonly used as a disinfectant in head and neck procedures. The present study investigated the effect of povidone-iodine, which is used as a disinfectant solution in tympanoplasty, on patients’ hearing.

Methods

A povidone-iodine solution was used as disinfection in chronic otitis media patients undergoing tympanoplasty. In the intervention group, 5% povidone-iodine, was applied to the external auditory canal and remained there for 10 minutes. In the control group, povidone-iodine was used but not allowed to enter the external auditory canal by inserting cotton wool into the canal. To evaluate the adverse effect of povidone-iodine on hearing, the bone conduction level was compared between groups at baseline and one month after exposure.

Results

Bone conduction levels at frequencies 500 Hz, 1 kHz, 2 kHz, 3 kHz, 4 kHz and 8 kHz and mean of bone conduction level in 500 Hz, 1 kHz and 2 kHz were measured and compared respectively between intervention and control group. No significant difference was seen between bone conduction levels of above frequencies and mean frequencies before and one month after surgery. (P-value = 0.321, 0.432, 0.219, 0.489, 0.61, 0.112, 0.324 respectively)

Conclusions

According to the present study, currently available 5% povidone-iodine did not affect hearing and therefore, can be comfortably used for preparation and disinfection in otologic surgeries.

Drug-Induced Ototoxicity: A Comprehensive Review and Reference Guide

OBJECTIVE

In an era of increasing polypharmacy, adverse drug effects such as ototoxicity have significant public health implications. Despite the availability of evidence, many health care professionals may not know the risk of ototoxicity in common medications. Therefore, the aim of this review is to provide a comprehensive, easy to use, ototoxic profile of medications with an assessment of supporting evidence.

METHODS

Medications of interest were identified through adverse drug reaction reports derived from Micromedex (IBM), Lexicomp (Wolters Kluwer), and the textbook, Drug Induced Diseases: Prevention, Detection, and Management. Additional evidence was identified though a query of PubMed and the Cochrane database. Evidence of causality was graded according to the following: A (randomized, controlled clinical trials), B (nonrandomized clinical trials, prospective observational studies, cohort studies, retrospective studies, case-controlled studies, and/or postmarketing surveillance studies), and C (case reports/case series).

RESULTS

A total of 194 systemically administered medications associated with ototoxicity were identified, most commonly antimicrobials (53), psychotropics (21), antihypertensive/antiarrhythmics (19), nonsteroidal antiinflammatory drugs (18), and antineoplastics (16). There was evidence of cochleotoxicity in 165 medications (evidence grading A [22], B [77], C [69]), vestibulotoxicity in 100 medications (evidence grading A [23], B [47], and C [30]), and dizziness in 142 medications (evidence grading A [50], B [76], and C [16]). In addition, a review of the evidence of ototoxicity in ototopical medications is also reviewed.

CONCLUSION

The effect and severity of ototoxicity can vary immensely depending on pharmacological and individual patient risk factors. The intent of this comprehensive review was to help health care providers of all sectors obtain a deeper knowledge of drug-induced ototoxicity to make more informed management decisions for their patients.

Potential Ototopical Antiseptics for the Treatment of Active Chronic Otitis Media: An In Vitro Evaluation

OBJECTIVES

Primary: to compare, in vitro, the antimicrobial activity of different antiseptic agents versus quinolone drops, against the common organisms of chronic otitis media.Secondary: to examine the possible role of pH on the antimicrobial activity of the antiseptic solutions.

METHODS

Three antiseptic powders (boric acid; iodine; and a 1:1 combination of these two) and four solutions (2% boric acid; 2% acetic acid; 3.25% aluminum acetate; and 5% povidone iodine) were tested against five bacteria and two fungi common in chronic otitis media, using both agar plates and the modified broth dilution method. These results were compared with the antimicrobial activity of quinolone drops.The potential role of pH of solutions was tested by reducing the acidity of the agents and repeating the broth dilution.

RESULTS

Of the powders, iodine, and iodine/boric acid combined, are very effective against all organisms. Boric acid powder showed moderate effectiveness against all organisms. All solutions performed poorly on the agar plates. 5% povidone iodine has good effectivity when tested with the broth dilution method. 3.25% aluminum acetate had the best activity against Pseudomonas aeruginosa.

CONCLUSION

Boric acid powder and 5% povidone iodine solution show promise for clinical use. Boric acid powder has proven clinical effectiveness. 5% povidone iodine requires further clinical research. Although very effective in vitro, iodine powder is toxic to tissues and cannot be recommended for clinical use. The pH of solutions does not seem to play a significant role in their antimicrobial activity in vitro.

Comparing Surgeon Adherence with World Health Organization Antiseptic Guidelines for Surgical Site Preparation in the United Kingdom and India

Background: Skin preparation with an antiseptic solution aims to reduce surgical site infection rates. Surgical site infections (SSIs) create a high burden on healthcare systems with impacts on morbidity, mortality, and cost. In 2016, The World Health Organization (WHO) conducted an extensive systematic review and meta-analysis of the existing evidence. From this, they recommended the use of "alcohol based antiseptic solutions based on CHG for surgical site skin preparation in patients undergoing surgical procedures." This study aimed to assess surgeon compliance with this guidance in the United Kingdom and India. Methods: A multiple-choice questionnaire was developed to assess surgeon preferences for antiseptic use in their surgical site preparation. The end point of data collection was defined after 50 responses in each region. Results: The majority of respondents in each center was general surgeons (n = 24, 48% United Kingdom; n = 21, 45% India), and registrars (n = 22, 44% United Kingdom; n = 23, 49% India). No surgeon preferred the use of any aqueous preparation. Chlorhexidine gluconate (CHG) was the preparation used most commonly in both centers (n = 30, 64% India; n = 24, 48% United Kingdom). In India, this represented a statistically significant difference (p = 0.0008), however, this was not observed in the United Kingdom (p = 0.22). There were no statistically significant differences between surgeon's reasons between the United Kingdom and India, other than "easier to see" (p = 0.016). Conclusions: This data show a reduced compliance of U.K. surgeons with WHO guidance for antiseptic use compared with Indian surgeons. Although the WHO has attempted to summarize the existing data to minimize the previous uncertainty surrounding antiseptic choices, the use of CHG continues to not be adopted widely. To draw robust conclusions to provide the foundations of further guidelines, future research should focus on prospective randomized controlled trials with large numbers across multiple surgical specialties.

Topical preparations to reduce SARS-CoV-2 aerosolization in head and neck mucosal surgery

AIM

The COVID-19 pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has put health care workers at risk when exposed to aerosolized viral particles during upper airway mucosal surgery. The objective of this review was to discuss topical preparations that could be utilized preoperatively to help to decrease viral load and potentially reduce the risks of viral transmission.

METHODS

A PubMed/MEDLINE database review of articles was performed querying topical preparations with virucidal activity against coronaviruses.

RESULTS

Povidone-iodine (PVP-I) solutions ranging from 0.23% to 7% have been found to demonstrate highly effective virucidal activity against a broad range of viruses including several coronaviruses responsible for recent epidemics including SARS-CoV-1 and MERS-CoV.

CONCLUSIONS

While specific evidence regarding SARS-CoV-2 is lacking, PVP-I-based preparations have been successfully demonstrated to reduce viral loads of coronaviruses. They are relatively safe to use in the upper airway and may reduce risk of SARS-CoV-2 aerosolization during upper airway mucosal surgery.

Mohs Micrographic Surgery at Challenging Anatomical Sites

BACKGROUND

Mohs micrographic surgery (MMS) is often the treatment of choice for skin cancer removal as it maximizes normal tissue sparing and can be paired with a reconstructive approach that optimizes function and cosmesis. Many tumors on the eyelid, nose, ear, and genitals are particularly well suited for MMS but can be challenging for the dermatologic surgeon.

OBJECTIVE

To review the complex anatomy, as well as the authors' approach to executing and interpreting Mohs layers, at each of these anatomical sites.

METHODS

A review of the literature on MMS of the eyelid, nose, ear, and genitals was performed using the PubMed database and relevant search terms.

CONCLUSION

These sites present potential pitfalls for tumor resection and reconstruction, but with the proper technique, the dermatologic surgeon can minimize tumor recurrence and MMS complications. Warning signs for potentially difficult tumor resection can signify when an interdisciplinary approach is warranted.

Efficacy of common reagents for killing ticks in the ear canal

Objective

To determine if widely available solutions can effectively kill ticks that may be found in the human ear canal.

Methods

This study was prospective, controlled and blinded animal study. Lone star ticks (Amblyomma americanum), both nymphal and adult, were submerged in one of four preparations (acetone, isopropyl alcohol 70%, ethanol 95%, or 4% lidocaine) in test tubes (n = 20 per group) for 20 minutes. Ticks were agitated by intermittent probing. Activity of the nymphal ticks was directly observed while those of the adult ticks was video‐recorded during the exposure period. Two blinded investigators viewed the videos of adult ticks and during the exposure period to determine the time until death (ie, movement cessation). Mortality was assessed immediately after exposure, and confirmed 24 and 48 hours after exposure.

Results

Acetone killed ticks most rapidly (nymph mean time = 185.1 s; adult mean time = 562.9 s). Isopropyl alcohol 70% (nymphs, 328.9 s; adults, 1128.4 s) and ethanol 95% (nymphs, 294 s; adults, 1129.4 s) took longer to kill the ticks. All ticks treated with 4% lidocaine survived. These differences were significant (nymphs, P < .0001; adults, P < .0001).

Conclusions

Acetone was the fastest acting and most effective reagent, followed by ethanol and isopropyl alcohol. These solutions may prove useful in otoacariasis with an intact tympanic membrane.

Level of Evidence

N/A