Commercial Quinolone Ear Drops Cause Perforations in Intact Rat Tympanic Membranes

Microbiome and Otic Quinolone Levels Following Tympanoplasty Assessed by Gelatin Sponge Analysis

OBJECTIVE

To determine if absorbable gelatin sponge (AGS) can be used to assess the posttympanoplasty microbiome and otic antibiotic exposure.

STUDY DESIGN

Prospective.

SETTING

Tertiary hospital.

METHODS

Patients undergoing tympanoplasty were prospectively enrolled. Intraoperatively, AGS was applied to the medial ear canal/tympanic membrane (TM) for 1 minute after canal incision, then saved for analysis. Ear canals were packed with AGS at the end of surgery. Otic ofloxacin was administered until the first postoperative visit, when AGS was collected. Microbial presence was assessed by culture. Ofloxacin levels were assessed by liquid-chromatography mass-spectrometry.

RESULTS

Fifty-three patients were included. AGS was collected in 92.9% of patients seen within 21 days compared to 70.8% of those seen at 22 to 35 days. At surgery, AGS yielded bacteria and fungi in 81% and 11%, respectively, including Staphylococcus species (55%) and Pseudomonas species (25%). Postoperatively, AGS yielded bacteria in 71% and fungi in 21% at the meatus, (staphylococci 57% and pseudomonas 25%). TM samples yielded bacteria in 69%, fungi in 6%, staphylococci in 53%, and pseudomonas in 19%. Ofloxacin concentration at the meatus was 248 μg/mL (95% confidence interval [CI]: 119-377) and at the TM was 126 μg/mL (95% CI: 58-194). Ofloxacin-resistant colonies were found in 75% of patients.

CONCLUSION

Analysis of AGS is a viable technique for noninvasively studying healing metrics posttympanoplasty, including the microbiome and otic antibiotic exposure. Despite exposure to a high concentration of quinolones, the tympanoplasty wound is far from sterile, which may impact healing outcomes.

Tympanoplasty Healing Outcomes With Use of Postoperative Otic Quinolones

OBJECTIVE

Tympanoplasty usually results in tympanic membrane perforation (TMP) closure, but healing may be suboptimal (e.g., excess scarring). Factors that have been linked to impaired TM healing have become widely adopted (especially, postoperative use of quinolone ear drops). The aim of this study is to assess the frequency of suboptimal tympanoplasty healing with the use of otic quinolones postoperatively.

STUDY DESIGN

Retrospective chart review.

SETTING

Tertiary care facility.

PATIENTS

One hundred patients undergoing tympanoplasty for TMP.

INTERVENTIONS

Tympanoplasty +/- canalplasty.

MAIN OUTCOME MEASURES

Healing complications (e.g., granulation tissue, TMP, myringitis, bone exposure, lateralization, anterior blunting, medial canal fibrosis, and canal stenosis) and hearing loss.

METHODS

Charts were reviewed for postoperative healing issues and hearing outcomes at 1 to 2 years postoperatively.

RESULTS

TMP closure was found in 93.2%, but 34.2% had healing issues at 1 to 2 years postoperatively, with 20.6% having adverse healing outcomes (perforation (6.9%), granulation tissue (6.9%), medial fibrosis (4.1%), and myringitis, bone exposure, and webbing (all 1.4%). Another 13.7% had notable postoperative issues, such as protracted otorrhea (11.0%), otitis externa (9.6%), otitis media (1.4%), and atelectasis (2.7%). No medical, surgical, or patient factors impacted outcomes. Average air-bone gap at 1 to 2 years did not differ between patients with and without healing issues and patients with other postoperative issues (p = 0.5).

CONCLUSIONS

Suboptimal healing is common after tympanoplasty. There may be significant opportunity to improve post-tympanoplasty healing beyond improving the TMP closure rate.

Structural Integrity of Absorbable Gelatin Sponges for Middle Ear Packing in Otologic Surgery

OBJECTIVE

This study investigates the physical properties upon immersion of two gelatin sponges commonly used in otologic surgery.

BACKGROUND

Absorbable gelatin sponges are often used in middle ear surgery to achieve hemostasis and, perhaps more importantly, to provide a "scaffolding" to support ossicular chain and/or tympanic membrane reconstructions. Their rate of dissolution may therefore affect the success of tympanic membrane closure.

METHODS

An in vitro study was conducted to quantify the material changes of two absorbable gelatin sponges, a standard-density sponge and one with fewer collagen cross-linkages (low-density sponge). Volume loss (%) in 0.9% saline, 0.3% ciprofloxacin, and/or 0.1% dexamethasone as single-agent otic drops in a combination formulation was measured at 15-minute intervals for the first hour and at days 1, 3, and 5 postimmersion. Secondary end points included compressibility, porosity under microscopy, and infrared spectroscopy analysis.

RESULTS

The low-density sponge immersed in any of the three otic solutions showed a statistically significant greater volume loss at all time points when compared with the standard-density sponge (27.2% ± 5.4% vs. 15.4% ± 6.0% at 15 minutes and 44.8% ± 5.1% vs. 34.6% ± 2.9% at 5 days, p < 0.001). Interestingly, both sponges immersed in normal saline had lost almost half of their original volume after 15 minutes when compared with samples immersed in an otic solution (48.3% ± 4.6% vs. 21.3% ± 8.3%, respectively, p < 0.001).

CONCLUSION

The standard-density sponge immersed in an otic solution of ciprofloxacin, dexamethasone, or a combination formulation best maintained its structural integrity. Ancillary in vivo studies are required to assess the hemostatic properties, surgical outcomes, and middle ear synechiae of the above study conditions.

LEVEL OF EVIDENCE

Foundational evidence.

Triangulation of pharmacoepidemiology and laboratory science to tackle otic quinolone safety

Background

The scientific method requires studies with high internal and external validity. Though both are necessary, they do not go hand‐in‐hand: The more controlled a study is to enhance internal validity, the less applicable to real‐world clinical care, and vice versa. In the many instances where evidence from clinical trials is not available, scientific inference must rely on more extreme approaches on this spectrum, such as mechanistic (limited generalizability/strong bias control) and real‐world evidence (RWE) studies (higher generalizability/lesser bias control).

Objectives

Illustrate how triangulating mechanistic and RWE studies can enhance scientific inference by delivering the supporting evidence for both.

Methods

We describe our research on an unexpected and highly unlikely drug safety issue: the risk of tympanic membrane (TM) perforations resulting from otic quinolone therapy. Tightly controlled laboratory studies using cell culture and rodent models were complemented with pharmacoepidemiological studies of real‐world data to translate mechanistic findings and corroborate RWE.

Results

We present a cascade of mechanistic and RWE studies investigating fibroblast cytotoxicity, delayed healing of perforated TMs, and spontaneous TM perforations after otic quinolone exposure, all suggesting local tissue toxicity.

Conclusion

Triangulation of mechanistic and RWE studies allowed incremental progress toward robust evidence on otic quinolone toxicity.

Does intraoperative ciprofloxacin-soaked gelfoam have adverse effects on graft success rate? A randomized, double-blind controlled trial

OBJECTIVES

The aim of this study was to evaluate whether intraoperative ciprofloxacin-soaked gelfoam is safe in tympanoplasty or not.

METHOD

In this randomized, double-blind controlled clinical study, we included 100 patients between 18 and 60 years old, having perforation ≥50% of the tympanic membrane and dry ear for at least 2 months who were a candidate for underlay tympanoplasty via postauricular approach. We used ciprofloxacin soaked gelfoam in the case group and betamethasone soaked gelfoam in the control group for packing the middle ear cavity and external auditory canal during their operation. The graft success rate and tympanogram after 6 months follow-up period was considered as the primary outcome. Also, we evaluated the postoperative hearing results 6 months after the surgery as the secondary outcomes.

RESULTS

Postoperative microscopic otoscopy showed a graft success rate of 100% (44/44) and 97.7% (42/43) in the case and control groups, respectively. The level of improvement between the two groups was not significant for air-bone gap (ciprofloxacin: 9.01 ± 7.89 dB, betamethasone 5.31 ± 10.53 dB, P = .160), and speech reception thresholds (SRT; ciprofloxacin: 10.23 ± 8.62 dB, betamethasone 7.33 ± 12.60 dB, P = .260). 93.2% of all the ears in the case group and 81.4% of those in the control group achieved postoperative air-bone gap within 20 dB, but the difference between them was not significant (P = .118).

CONCLUSIONS

We found that the application of ciprofloxacin impregnated gelfoam in the middle ear, and the external auditory canal had no adverse effect on the graft success rate in tympanoplasty.

LEVELS OF EVIDENCE

1b.

Effects of quinolone and poloxamer otic suspension on rat tympanic membranes

OBJECTIVES

Commercial quinolone ear drops (0.3%) delivered twice daily for 10 days cause tympanic membrane perforations (TMPs) in rats. We aimed to evaluate if a single application of 6% quinolone in poloxamer causes TMPs in rats.

METHODS

Rats were randomized to 5 groups (10/group), with one ear receiving a single otic instillation of 16% poloxamer 407 or 188 (as found in a commercial otic preparation and a wound dressing), or ofloxacin, ciprofloxacin, or neomycin at 6% in suspension with 16% poloxamer 407. The contralateral ear received saline. Rats were assessed over 42 days.

RESULTS

No TMPs were seen in ears treated with saline, poloxamer 407 or 188, or in ears treated with ofloxacin-, ciprofloxacin-, or neomycin-poloxamer suspension. White precipitates were observed on the canal or tympanic membrane of ciprofloxacin and ofloxacin-treated ears. Precipitates were more common in ciprofloxacin-treated ears until day 10 (p < 0.0001 to p = 0.0004). Tympanic membrane surface irregularities, were also observed mostly in the ciprofloxacin-treated ears from day 3-42 (p = 0.03 to p = 0.0033).

CONCLUSIONS

Quinolone in poloxamer otic preparations may be a safer therapeutic alternative to conventional quinolone ear drops in ears with intact TMs, particularly those felt to be at risk for developing TMPs.

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.

The Effects of Steroids on Survival of Mouse and Human Tympanic Membrane Fibroblasts

OBJECTIVE

Tympanic membrane (TM) fibroblast cytotoxicity of quinolone ear drops is enhanced by dexamethasone and fluocinolone. Hydrocortisone has not been evaluated. We aimed to assess the effects of these 3 steroids on mouse and human TM fibroblast survival.

STUDY DESIGN

In vitro.

SETTING

Academic laboratory.

SUBJECTS AND METHODS

Mouse and human TM fibroblasts were exposed to hydrocortisone, dexamethasone, or fluocinolone at concentrations in commercial ear drops (1%, 0.1%, or 0.025%, respectively) and at steroid potency equivalents (1%, 0.033%, or 0.0033%, respectively), or dilute ethanol (control), twice within 24 hours or 4 times within 48 hours for 2 hours each time. Cells were observed with phase-contrast microscopy until the cytotoxicity assay was performed.

RESULTS

Mouse and human TM fibroblasts treated with any of the steroids had lower survival after 24 and 48 hours compared to control (all P < .0001). After 24 hours, viability of mouse fibroblasts treated with the steroids was not different (P > .05), while treatment with hydrocortisone decreased human TM fibroblast viability (P < .0001). After 48 hours, at concentrations found in ear drops and at equivalent steroid potency, dexamethasone and fluocinolone had similar survival in mouse and human fibroblasts (all P > .05), but hydrocortisone had lower survival in both mouse (P = .02 and P < .0001) and human (P < .0001) fibroblasts. Phase-contrast images mirrored the cytotoxicity findings.

CONCLUSION

Steroids found in commercial ear drops reduce survival of mouse and human TM fibroblasts. Hydrocortisone appears to be more cytotoxic than the more potent steroids, dexamethasone and fluocinolone. These findings should be considered when assessing clinical outcomes of ototopical preparations.