Histologic analysis of the effects of three different support materials within rat middle ear

A Post-marketing Surveillance, Single-Centric Study to Evaluate the Safety and Tolerability of VELNEZ as a Space-Occupying Dressing Pack After Ear Surgery

PURPOSE

The purpose of this study was to evaluate the safety and tolerability of VELNEZ (Datt Mediproducts Pvt. Ltd., New Delhi, India) as a space-occupying dressing for controlling hemorrhage after ear surgery.

METHOD

A total of 21 patients were included in an open-label, interventional, single-arm post-marketing surveillance study to investigate the safety and efficacy of the VELNEZ ear pack. The patients were questioned for collecting data related to the subject's safety and comfort, adverse events, site assessment, and otoscopic examination from discharge day to last follow-up (eight follow-up visits) at regular intervals. The standardized questionnaires for VELNEZ tolerability (pain/pressure effect, infection, and general satisfaction) were used after ear surgery.

RESULTS

 The average hemorrhage control time was 1.08 ± 0.16 minutes. None of the subjects reported moderate pain at any of the study visits following surgery. This biodegradable ear pack had an average disintegration time of 25.4 days in the ear cavity. No postoperative adverse events or serious adverse events were observed.

CONCLUSION

VELNEZ is safe and effective as a space-occupying dressing pack after ear surgery and is well-tolerated by patients.

Comparison of endoscopic over-underlay technique with and without packing for repairing chronic perforation

OBJECTIVE

This study was performed to compare the efficacy of the endoscopic modified cartilage over-underlay technique with and without packing for repairing chronic tympanic membrane (TM) perforations.

METHODS

A total of 70 cases of chronic TM perforation were randomly allocated to endoscopic modified cartilage over-underlay myringoplasty groups with (n = 35) and without (n = 35) packing. The graft success rate and hearing outcomes were compared between the two groups. In addition, neovascularization scores were subjectively obtained.

RESULTS

At 12 months postoperatively, the difference in graft success rate between the packing and no-packing groups was not significant (94.3% vs. 100.0%, P = 0.473). In addition, there were no significant differences between the two groups in the pre- or postoperative air-bone gap (ABG) (15.18 ± 2.73 vs. 15.07 ± 4.02, P = 0.623 and 8.63 ± 3.03 vs. 8.52 ± 4.50, P = 0.591) or mean ABG gain (6.56 ± 3.23 vs. 6.54 ± 2.83, P = 0.751). However, the average operating times were 43.6 ± 7.1 and 32.7 ± 2.1 min in the packing and no-packing groups, respectively (P < 0.001).

CONCLUSIONS

Surgical and hearing outcomes were comparable between patients with chronic TM perforation treated using the endoscopic modified over-underlay technique with and without packing. However, without packing, the procedure was less invasive and had a shorter operating time.

Is no de-squamatization of the TM reliable for cartilage over-underlay myringoplasty without external auditory canal packing?

OBJECTIVE

We evaluated the graft and hearing outcomes of patients with chronic perforations treated via the cartilage-perichondrium over-underlay technique without de-squamatization of the TM and external auditory canal (EAC) packing.

MATERIALS AND METHODS

Thirty-nine patients with chronic perforations and residual tympanic membranes around the perforation margins were treated using the cartilage-perichondrium over-underlay technique without de-squamatization of the TM and EAC packing. Patients were followed-up for 6 months.

RESULTS

For all 39 patients with unilateral perforations, the graft success rate was 100% (39/39) at 6 months after surgery. The mean air-bone gap significantly (P < 0.05) improved from 13.41 ± 8.34 dB preoperatively to 7.45 ± 3.81 dB postoperatively in patients with small and medium perforations; the mean air-bone gap significantly improved from 20.57 ± 9.41 dB preoperatively to 9.84 ± 2.41 dB postoperatively in patients with large perforations. The lateral perichondrium gradually became necrotic and crust at postoperative 2-3 months and migrated into the EAC in all patients.

CONCLUSIONS

The cartilage-perichondrium over-underlay myringoplasty without de-squamatization of the TM and EAC packing is feasible, affording a high graft success rate and good hearing improvement. The lateral perichondrium may gradually become necrotic and crusted, and migrate along the EAC over time.

Is gelfoam sealing necessary in stapes surgery?

BACKGROUND

Sealing the oval window around the piston after fenestration with Gelfoam^® is a common practice in stapes surgery for otosclerosis.

OBJECTIVES

To analyse the effect of using or not using Gelfoam^® as a sealing material.

METHODS

A retrospective study was performed on 418 patients who underwent stapes surgery from 2013 until 2019. Data were collected from medical records in a tertiary centre. 215 cases in the Gelfoam group and 203 cases in the control group without sealing were included. The main comparisons were made between these two groups in terms of vestibular (primary outcome) and audiological outcomes and complications.

RESULTS

The patients' mean age was 47 years with a mean follow up of 50 months and a female predominance (65.6%, p = .049). There was no significant difference in terms of postoperative vertigo (11.6% vs 8.4%) or audiological outcomes in between Gelfoam and control group respectively. The average postoperative air-bone gap in the Gelfoam group was 4.6 dB vs. 5.3 dB in the control group (p = .634).

CONCLUSION AND SIGNIFICANCE

No difference were identified in vestibular or audiological outcomes during stapes surgery when using or not using Gelfoam^® in the middle ear.

Endoscopic full-thickness cartilage-perichondrium double graft myringoplasty in adhesive perforation: retrospective case series

BACKGROUND

The adhesive perforation could be the sequela of adhesive otitis media, that partial tympanic membrane remnant is bound completely to the medial wall of the middle ear by fibrous adhesions. However, few studies have reported on the repairing of adhesive perforation.

OBJECTIVES

To evaluate the long-term outcome of endoscopic full-thickness cartilage-perichondrium double graft myringoplasty for adhesive perforation.

MATERIALS AND METHODS

In total, 26 patients with unilateral adhesive perforation associated with chronic otitis media who underwent full-thickness cartilage-perichondrium double graft myringoplasty were included. Outcomes were evaluated in terms of the hearing gain and graft success rate at 12 and 24 months.

RESULTS

The graft success rate was 96.15% (25/26) at 12 months and 88.46% (23/26) at 24 months. The neovascularization and epithelium covering the lateral surface of the cartilage graft were seen at preoperative 4 weeks, the superficial cartilage graft got complete epithelialization within 4-6 months. CT revealed the well-pneumatized middle ear and mastoid cells at postoperative 24th months in all the patients, no middle ear cholesteatoma formation and keratin pearls were found during the period of follow up.

CONCLUSIONS

Endoscopic full-thickness cartilage-perichondrium double graft myringoplasty without the tympanomeatal flap elevation is a feasible method for repairing adhesive perforations, with a higher graft success rate and satisfactory hearing results.

Effect of middle ear gelfoam on hearing and healing process after tympanoplasty: A prospective randomized case-control study

PURPOSE

This prospective randomized case-control study was performed to compare the surgical outcomes of our swing-door overlay tympanoplasty with or without absorbable gelatine sponge (AGS, gelfoam) packing in the middle ear cavity, according to the surgical procedure.

METHODS

Fifty-seven patients who underwent swing-door overlay tympanoplasty by a single surgeon were enrolled in the study. The data of 30 patients of the gelfoam-packing group (GPG) and 27 patients of the non-gelfoam-packing group (NGPG) were prospectively collected and compared.

RESULTS

Closure of the tympanic membrane was found to be successful in all patients at postoperative 3 months evaluation. NGPG showed a statistically better healing process compared to GPG; earlier epithelialization and less fascia edema in NGPG than in GPG (P < 0.05). The air-bone gap (ABG) measured at postoperative 1 and 2 months was smaller in NGPG than GPG, although there were no statistical differences.

CONCLUSION

This study revealed earlier healing process and faster recovery of ABG in NGPG, thereby indicating that the gelfoam in the middle ear may interfere with both hearing recovery and the healing process of neodrum.

The Effect of External Auditory Canal Packing Duration on Healing After Endoscopic Cartilage Myringoplasty

INTRODUCTION

The external auditory canal (EAC) packing is widely used in otosurgery and is considered to promote hemostasis and to support tympanic membrane grafts. However, few studies have investigated the effects of packing removal time on healing.

OBJECTIVE

We investigated the effect of EAC packing duration on healing after endoscopic cartilage myringoplasty in patients with chronic tympanic membrane perforations (TMPs).

MATERIALS AND METHODS

Patients with chronic TMPs who underwent endoscopic "push-through" cartilage myringoplasty were divided into early and late groups based on the length of time before EAC packing was removed. The graft success rate, eardrum appearance, and hearing gain were assessed 3 months after surgery.

RESULTS

The study included 137 patients. Three months after surgery, the graft success rate was 83.5% (66/79) in the early group and 94.8% (55/58) in the late group (P = .042). The graft was displaced in 8 (10.1%) patients in the early group and in 1 (1.7%) patient in the late group (P = .050). No epithelialization was found on the surface of the grafts in the early group, whereas epithelialization was nearly complete 4 weeks after surgery in the late group.

CONCLUSIONS

Delaying removal of the EAC packing after endoscopic cartilage myringoplasty may promote tympanic membrane better healing and cartilage graft epithelialization and improve the appearance of the eardrum.

The outcomes of endoscopic myringoplasty: packing with gelatin sponge versus packing with nothing

Background: Packing with gelatin sponge has long been widely used in myringoplasty. However, there is no research on packing with nothing.Aims/objectives: To analyse the differences between packing with gelatin sponge and packing with nothing.Material and methods: Patients with tympanic membrane perforation were randomly divided into a packing with gelatin sponge group and a packing with nothing group. Differences between the groups were compared.Results: The operation time of group A (34.00 ± 1.05 min) was significantly shorter than that of group B (42.20 ± 1.40 min; p < .00); 1 patient (2.86%) in group A and 35 patients (100%) in group B had a dry ear time of longer than 1 week (p < .001). Ten patients (28.57%) in group A and 24 patients (68.57%) in group B had aural fullness after the operation (p < .001). The air-bone gap (ABG) in group A was smaller than that in group B at 1 week, 1 month, 2 months and 3 months after the operation (p < .05).Conclusion and significance: Group A achieved the same good results, but it had a short operation time, an early dry ear time, a low incidence of aural fullness and early recovery of hearing.

Endoscopic cartilage myringoplasty with the removal of a small rim of the external auditory canal to repair marginal perforations

Objective

To evaluate the graft success rate and postoperative hearing gain for marginal perforations using endoscopic cartilage myringoplasty with the removal of a small rim of the external auditory canal (EAC).

Study design

Prospective case series.

Materials and methods

We performed a prospective study in 41 patients with marginal perforations who underwent endoscopic cartilage myringoplasty with the removal of a small rim of EAC. Patients were followed up for 6 months.

Results

Of the 41 patients with unilateral marginal perforation included in this study, the graft success rate was 100% (41/41). The mean ABG improved from 11.31 ± 9.71 dB preoperatively to 7.31 ± 2.32 dB postoperatively for small-and medium-sized perforations (P = 0.13); the mean ABG improved from 21.46 ± 8.39 dB preoperatively to 9.84 ± 2.41 dB postoperatively for large perforations (P < 0.05); the mean ABG improved from 28.79 ± 6.74 dB preoperatively to 10.13 ± 3.56 dB postoperatively for subtotal and total perforations (P < 0.05). There were no cases of graft lateralization or significant blunting or atelectasis or graft adhesions. Three patients developed postoperative otorrhoea and five patients had mild myringitis.

Conclusions

Endoscopic cartilage myringoplasty with the removal of a small rim of the EAC is simple and feasible, showing a high graft success rate and minimal complications for repairing marginal perforations.

Identification of early inflammatory changes in the tympanic membrane with Raman spectroscopy

The tympanic membrane (TM) is a dynamic structure that separates the middle ear from the external auditory canal. It is also integral for the transmission of sound waves. In this study, we demonstrate the feasibility of using Raman spectroscopy to identify early chemical changes resulting from inflammation in the TM that can serve as an indicator of acute otitis media. Bacterial lipopolysaccharide (LPS) was injected trans-tympanicaly in a murine model. Presence of inflammatory response was assessed with binocular microscopy, confirmed with histopathology and immunofluorescence staining. Successful discrimination suggesting spectral differences among the control and LPS treated groups was achieved using principal component analysis. Raman imaging revealed major differences in collagen distribution and nucleic acid content. Image segmentation analysis on the trichrome stained tissue sections was performed to corroborate the Raman spectra. The spectral co-localization study suggests changes in the expression of collagen IV specific signals in LPS treated samples. The overall findings of the study support prospective application of RS in the diagnosis and therapeutic monitoring of otitis media.

The effects of different packing materials on healing and hearing after trauma to middle ear mucosa, an experimental study in rats

PURPOSE

To compare the performance of Spongostan, Otopore, Spongostan soaked with dexamethasone and Spongostan soaked with Hyaluronic acid (HA) as middle ear packing material after mucosal trauma.

METHODS

Twenty rats were divided into 4 groups. In control group (group 1), the middle ear cavities of animals were bilaterally packed with Spongostan; in group 2, with Otopore; in group 3, with Spongostan soaked with dexamethasone; and in group 4, with Spongostan soaked with HA. Auditory brainstem responses (ABRs) were performed preoperatively and 1 and 6 weeks postoperatively. Histological analyses were performed to evaluate the inflammatory reaction and wound healing in the middle ear cavity.

RESULTS

ABR recordings demonstrate that threshold level changes from baseline were minor in Otopore and Spongostan soaked with dexamethasone packed ears. Threshold levels were higher in the Spongostan and Spongostan soaked with HA packed ears compared with both Otopore and Spongostan soaked with dexamethasone packed ears. Histological analyses showed that Spongostan caused inflammation more intense than Otopore and Spongostan soaked with dexamethasone. Residual material at postoperative week 6, new bone formation and adhesion were common in the Spongostan group compared with other groups. Fibrosis was more common in Spongostan group compared with other groups but the difference was not significant.

CONCLUSION

Otopore appears to be safe and effective for use in otologic surgery. The inflammation, adhesion and new bone formation decreased when Spongostan was used with steroid or HA, when compared to Spongostan alone.

Alginate Ototoxicity in the Mouse Model

Objective To determine whether alginate exposure to the round window of the mouse causes any measurable ototoxicity. Study Design Prospective animal study. Setting Basic science laboratory affiliated with a tertiary care university medical center. Subjects and Methods After Institutional Animal Care and Use Committee approval, 5 adult mice were obtained and underwent bullostomy and round window niche application of alginate. Auditory brainstem response (ABR) tests were completed at baseline prior to the procedure and also 5, 14, and 30 days postprocedure. Results were compared. At termination of procedure, the mice were sacrificed with harvest of the cochleae, which were viewed under histologic section. Results There were no significant increases in ABR thresholds in any of the test animals at all test periods after alginate exposure compared to baseline. There were also no observable behavioral changes after the procedure to indicate vestibular dysfunction. Cochlear sectioning revealed no evidence of histologic damage. Conclusion Exposure of alginate to the round window does not cause any obvious ototoxicity in the mouse model. Further clinical trials will be needed to elucidate the effect of alginate in the human middle ear.

The effects of fibroblast growth factor-2 delivered via a Gelfoam patch on the regeneration of myringosclerotic traumatic eardrum perforations lying close to the malleus

OBJECTIVE

We evaluated the effects of fibroblast growth factor-2 (FGF-2) delivered via a Gelfoam patch on the regeneration of myringosclerotic traumatic tympanic membrane perforations (TMPs) lying close to the malleus.

STUDY DESIGN

A prospective, randomized, controlled clinical study.

SETTING

A university-affiliated teaching hospital.

SUBJECTS AND METHODS

We prospectively analyzed, in a randomized manner, the outcomes of treatment for traumatic TMPs constituting >25% of the tympanic membrane. The closure rates, closure times, and otorrhea rates were compared among patients treated via FGF-2-containing Gelfoam patches, Gelfoam patches alone, and observation only.

RESULTS

We analyzed data from 138 patients. The perforation closure rates in the FGF-2 plus Gelfoam patch, Gelfoam patch, and observation alone groups were 97.9, 89.8, and 70.7%, respectively. Both the FGF-2 plus Gelfoam and Gelfoam alone groups exhibited significantly higher closure rates than the observational group (both p<0.05).The mean closure times were 15.7±5.1, 24.8±4.9, and 35.7±9.2days in the FGF-2 plus Gelfoam patch, Gelfoam patch alone, and observation alone groups, respectively. The FGF-2 plus Gelfoam patch group exhibited a significantly shorter closure time than the Gelfoam patch alone and observation alone groups (p<0.05). The incidences of purulent otorrhea were 14.6, 6.1, and 4.9% in the FGF-2 plus Gelfoam patch, Gelfoam patch alone, and observation alone groups, respectively. Surprisingly, 7 of 7 (100.0%) perforations associated with purulent otorrhea completely closed in the FGF-2 plus Gelfoam patch group; however, no such perforation healed in either the Gelfoam alone or observation alone group.

CONCLUSIONS

FGF-2 plus Gelfoam patching significantly shortened the closure time compared to observation and Gelfoam patching alone, and it significantly improved the closure rate (compared to observation alone) of myringosclerotic perforations lying close the malleus. FGF-2 plus Gelfoam patching is a valuable, minimally invasive alternative treatment that may be readily applied to outpatient settings.

Ototoxicity of boric acid powder in a rat animal model

Introduction

Boric acid, which has antiseptic and acidic properties, is used to treat external and middle ear infections. However, we have not found any literature about the effect of boric acid powder on middle ear mucosa and inner ear.

Objective

The purpose of this study is to investigate possible ototoxic effects of boric acid powder on cochlear outer hair cell function and histological changes in middle ear mucosa in a rat animal model.

Methods

Twenty healthy, mature Wistar albino rats were used in this study. The rats were divided into two groups, Group A and Group B, each of which consisted of 10 rats. Initially, the animals in each group underwent distortion product otoacoustic emissions testing of their right and left ears. After the first distortion product otoacoustic emissions test, a surgical microscope was used to make a small perforation in both ears of the rats in each group, and a second distortion product otoacoustic emissions test was used to measure both ears in all of the rats. Boric acid powder was applied to the right middle ear of the rats using tympanic membrane perforation, and the distortion product otoacoustic emissions were measured immediately after the boric acid powder application. The histological changes and distortion product otoacoustic emissions were evaluated three days later in Group A and 40 days later in Group B.

Results

No significant differences were found at all of the distortion product otoacoustic emissions frequencies. In Group A, mild inflammation of the middle ear mucosa was found on the third day after boric acid powder application. In Group B, boric acid powder caused mild inflammatory changes on the 40th day, which declined over time. Those changes did not lead to significant fibrosis within the mucosa.

Conclusion

In rats, boric acid powder causes mild inflammation in middle ear mucosa and it has no ototoxic effects on cochlear outer hair cell function in the inner ear of rats.

Comparison of packing material in an animal model of middle ear trauma

PURPOSE

To compare the performance of absorbable gelatin sponge (AGS) with polyurethane foam (PUF) as middle ear packing material after mucosal trauma.

MATERIALS AND METHODS

Using a randomized, controlled and blinded study design fifteen guinea pigs underwent middle ear surgery with mucosal trauma performed on both ears. One ear was packed with either PUF or AGS while the contralateral ear remained untreated and used as non-packed paired controls. Auditory brainstem response (ABR) thresholds were measured pre-operatively and repeated at 1, 2, and 6weeks postoperatively. Histological analysis of middle ear mucosa was done in each group to evaluate the inflammatory reaction and wound healing. Another eighteen animals underwent middle ear wounding and packing in one ear while the contralateral ear was left undisturbed as control. Twelve guinea pigs were euthanized at 2weeks postoperatively, and six were euthanized at 3days post-operatively. Mucosal samples were collected for analysis of TGF-β1 levels by enzyme-linked immunosorbent assay.

RESULTS

ABR recordings demonstrate that threshold level changes from baseline were minor in PUF packed and control ears. Threshold levels were higher in the AGS packed ears compared with both control and PUF packed ears for low frequency stimuli. Histological analysis showed persistence of packing material at 6weeks postoperatively, inflammation, granulation tissue formation, foreign body reaction and neo-osteogenesis in both AGS and PUF groups. TGF-β1 protein levels did not differ between groups.

CONCLUSION

PUF and AGS packing cause inflammation and neo-osteogenesis in the middle ear following wounding of the mucosa and packing.

A melting method for RNA extraction from the mucosal membrane of the mouse middle ear

PURPOSE

There is much confusion surrounding the methods of RNA extraction from the middle ear mucosa of mice. In this study, we worked to develop a "melting method," which is faster, purer, and more reliable than other methods in common use.

MATERIALS AND METHODS

Thirty-two ears were used for this study. Light microscopy with hematoxylin-eosin staining of the bullae, scanning electron microscopy (SEM), spectrophotometer analysis, and reverse transcription polymerase chain reaction were performed before and after melting the half lateral bullae, which were detached from the temporal bone by using a lateral retroauricular approach.

RESULTS

Each resected half bulla contained a well distributed mucosal membrane. After a TRIzol melting duration of 10-30 minutes, only mucosal marker (MUC5AC) was expressed without bony marker (total osteocalcin). The same results were determined from SEM.

CONCLUSION

This melting method, compared with stripping and irrigation methods, is effective and offers an easier, more robust approach to extracting RNA from the middle ear mucosal membranes of mice.

Antiadhesive effect of polyurethane foam packing in the guinea pig middle ear

CONCLUSIONS

No significant subepithelial healing differences were found between Gelfoam and polyurethane foam (PUF). However, levels of hyperplasia of the mucosal lining and inflammation were lower with PUF packing. PUF packing is not feasible as a middle ear packing material for abraded mucosa. Further studies are required before clinical application.

OBJECTIVE

To date, there have been few reports on the antiadhesive effect of PUF as a middle ear packing. The purpose of this study was to investigate the antiadhesive effect of PUF soaked with saline in an animal model of mucosal trauma.

METHODS

Bioresorbable PUF soaked with saline was placed over abraded mucosa in the experimental group (n = 7), and compressed Gelfoam soaked with saline was placed in the control group (n = 7). After measurement of auditory brainstem responses (ABRs), the animals were sacrificed 3 weeks after packing placement for histological observation.

RESULTS

The ABR results at postoperative week 3 showed no statistically significant difference between the preoperative and post-packing values. An adhesion pattern with subepithelial thickening was observed in the control group. Adhesion was not observed in the experimental group; however, subepithelial fibrous thickening was noted.

Effect of absorbable gelatin sponge in the middle ear: in vitro and in vivo animal model

CONCLUSION

GelitaSpon gelatin sponge (GS) showed faster reabsorption than gelfoam (GF) in vitro, and GS-packed middle ears resulted in a faster hearing recovery and less inflammation than the ears packed with GF soaked in saline. Soaking GF sponges with boric acid (BA) appeared to offset the inflammatory response of saline-soaked GF, making this inflammatory response comparable to that of GS-packed ears.

OBJECTIVE

To describe the reabsorption and inflammatory effects of absorbable gelatin sponge in the middle ear.

METHODS

For in vitro evaluation, GF and GS were used as disks immersed in saline solution or 3% BA and placed in gel. Images were captured with a microscope and processed using image processing Toolbox. For in vivo tests, 16 female albino Sprague Dawley rats were divided into four groups: bulla opening; GF + 0.9% saline; GF + BA; and GS + 0.9% saline. An anterior approach to the right bulla was used for surgery. Preoperative and postoperative auditory brainstem response thresholds were measured.

RESULTS

In vitro, there was marked degradation of GF by day 14, while GS showed complete degradation by the third day. In vivo, hearing recovery occurred by day 21. GF produced a more severe inflammatory response, which could be reduced by treating the GF with BA.

Mucosal trauma induced apoptosis in guinea pig middle ear: comparision of hemostatic agents

OBJECTIVE

The aim of this study is to compare the effects of the absorbable gelatin sponge (AGS), microporous polysaccharide hemospheres (MPH), and Ankaferd on wound healing after middle ear trauma and to evaluate their ototoxicity in an experimental guinea pig model.

METHODS

Middle ear mucosal trauma was created in 21 healthy adult guinea pigs. MPH, Ankaferd, and AGS were applied into the right tympanic bulla of the guinea pigs (7 ears for each treatment modality). The left ears of the seven animals were used as the sham group. At the fourth postoperative week (28-30 days), the guinea pigs were decapitated. Apoptosis was investigated, and the expression of Bcl-xl, Apaf, p53, cytochrome 3, and caspase 3 were evaluated.

RESULTS

The Ankaferd and AGS groups demonstrated significantly lower epithelial thickness, inflammation, and capillary dilatation than did the control group (p<0.001, <0.001, /0.001, <0.001/, 0.005, and 0.005, respectively). A statistically significant decrease in Bcl-xl staining was observed in the middle ears of animals treated with MPH (p=0.003). There was significantly higher caspase 3 expression in the Ankaferd and AGS groups than in the control group (p<0.001 and p=0.002, respectively).

CONCLUSION

Light microscopy indicates that Ankaferd and AGS create less inflammation and increased caspase expression, which seems to induce inflammatory cell apoptosis. Ankaferd seems to be a promising hemostatic agent in otology.

OTO-201: nonclinical assessment of a sustained-release ciprofloxacin hydrogel for the treatment of otitis media

HYPOTHESIS

OTO-201 can provide sustained release to the middle ear and effectively treat otitis media, when compared with FDA-approved ciprofloxacin otic drop formulations.

BACKGROUND

There is an unmet medical need for antibiotic therapy that can provide a full course of treatment from a single administration by an otolaryngologist at the time of tympanostomy tube placement, obviating the need for twice daily multiday treatment with short-acting otic drops.

METHODS

Studies in guinea pigs and chinchillas were conducted. OTO-201 was administered as a single intratympanic injection and compared with the twice daily multi-day treatment with Ciprodex or Cetraxal otic drops.

RESULTS

OTO-201 demonstrated sustained release of ciprofloxacin in the middle ear compartment for days to approximately 2 weeks depending on the dose. The substantial C(max) values and steady drug exposure yielded by OTO-201 were in contrast to the pulsatile short lasting exposure seen with Ciprodex and Cetraxal. OTO-201 was also effective in a preclinical chinchilla model of Streptococcus pneumoniae-induced otitis media. The degree of cure was comparable to that afforded by Ciprodex and Cetraxal. There was no evidence of middle or inner ear pathology in guinea pigs treated with OTO-201, unlike Ciprodex and Cetraxal, which both demonstrated mild cochlear ototoxicity. No adverse effects of the poloxamer 407 vehicle were noted.

CONCLUSION

Intratympanic injection of OTO-201 constitutes an attractive treatment option to twice daily multiday dosing with ciprofloxacin ear drops for the treatment of otitis media, as evidenced by superior middle ear drug exposure, efficacy in an acute otitis media model, safety of administration, and convenience of a single dose regimen.

Histological analysis of the effects of anti-adhesive haemostatic agents on the middle ear of the guinea pig

INTRODUCTION

Adhesion formation is a frequent and serious post-operative problem in ENT surgery. This study assessed the effect of two anti-adhesive haemostatic agents on an experimental guinea pig model.

MATERIALS AND METHODS

The middle-ear mucosa of 14 guinea pigs was exposed to surgical trauma. After surgery, Arista™ AH was injected into the right middle ear of seven animals, while Ankaferd Blood Stopper was injected into the right middle ear of the other seven animals. The left ears were left untreated and regarded as the control group. The three groups were compared by histological examination at post-operative week 4.

RESULTS

In each of the three groups, consolidation of the lamina propria and epithelium mucosae, increments in the number of active fibroblasts, collagen fibrils and inflammatory cells, and increased vascular dilation were observed on haematoxylin and eosin-stained sections, and were more prominent in the control and Ankaferd Blood Stopper groups. Epithelial thickness and capillary vasodilation were significantly lower in the Arista™ AH group compared with the control and Ankaferd Blood Stopper groups (p < 0.008).

CONCLUSION

Arista™ AH may prevent the formation of adhesions in middle-ear surgery. Further experimental studies are required to determine its ototoxic potential.

Middle ear packing materials: comparison between absorbable hemostatic gelatine sponge and sugarcane biopolymer sponge in rats

Introduction

Several biomaterials can be used in ear surgery to pack the middle ear or support the graft. The absorbable gelatin sponge is the most widely used, but it may produce fibrosis and impair ventilation of the middle ear.

Objective

This experimental study aimed to investigate the inflammatory effects of the sugarcane biopolymer sponge (BP) in the rat middle ear compared with absorbable gelatin sponge (AGS).

Materials and methods

Prospective experimental study design. Thirty adult female Wistar rats were allocated to receive the BP sponge into the right ear and AGS into the left ear. Animals were randomly killed at 4 and 12 weeks post-procedure. Qualitative histological assessments were performed to evaluate the inflammatory reaction in the tympanic bullae.

Results

The BP sponge caused inflammation more intense and persistent than AGS. The BP was not absorbed during the experiment. Fibrosis was observed only in the ears with AGS. There were thickening of the mucosa and neoangiogenesis in the group of AGS.

Conclusion

Despite inflammation, the BP sponge produced less fibrosis and neoangiogenesis compared to AGS. The sponge BP appeared to be a non-absorbable biomaterial in the middle ear.

Effects of middle ear packing with collagen polyvinylpyrrolidone and hyaluronic acid in guinea pigs

OBJECTIVE

The aim of this study was to evaluate otoscopic and microscopic changes produced on the healthy mucosa of the middle ear (ME) and tympanic membrane (TM) of guinea pigs after packing with a collagen polyvinylpyrrolidone (CPVP) sponge soaked in hyaluronic acid (HA).

MATERIAL AND METHODS

In 24 guinea pigs, myringotomy on the right side was created and the ME was packed as follows: Group I (n = 6): Absorbable gelatin sponge (AGS) soaked in saline solution; Group II (n = 6): AGS sponge soaked in HA, Group III (n = 6): CPVP sponge soaked in saline solution, Group IV (n = 6): CPVP sponge soaked in HA. Four weeks after miringotomy, the ME and TM integrity and residual packing material were evaluated otoscopically. Histologically, we evaluated inflammatory changes on the ME mucosa.

RESULTS

All animals in Groups I and II showed residual packing material (p < .001 ANOVA, TUKEY). Histologically, more inflammation was observed in Groups I, II, and III than in Group IV (p < .001 ANOVA, TUKEY). Group IV showed greater fibroblastic reaction (p < .02, ANOVA, TUKEY) versus other groups.

CONCLUSION

The CPVP sponge soaked in HA used as ME packing material is biocompatible and nontoxic, because it produces minimal inflammatory changes on the healthy mucosa of the ME and TM of guinea pigs. However, more research with injured mucosa is needed to validate its usefulness in otosurgery.

Healing of laser-induced tympanic membrane perforations in rats: no contribution of granulocyte colony-stimulating factor or Gelfoam

OBJECTIVES

To study whether granulocyte colony-stimulating factor together with Gelfoam (absorbable gelatin sponge, USP) could enhance the healing of freshly perforated tympanic membranes. The frequency and occurrence of different immunocompetent cells and collagen types was noted.

METHODS

Laser perforations were made in the tympanic membrane of rats that were sacrificed at different time intervals post-myringotomy: Day 1, 3, 6, and 12. Tympanic membrane specimens were embedded and sections were stained with hematoxylin/eosin and an immunohistochemical technique was used, with antibodies against macrophages, B-cells, T-cells, and type I-IV collagens. Semi-quantification was performed after counting positive cells, mean values were calculated and analyzed statistically.

RESULTS

All perforations, except one, had closed by Day 12 and no difference was observed between experimental and control ears at the other time points. Gelfoam was still present in a high amount at Day 12. The sections were initially stained positive for type I and II collagen, but after Day 6, the regenerating tissue stained positive for mainly type III and IV collagens. Results showed that the recruitment of macrophages, B-cells, and T-cells could not be mapped with a statistical significance.

CONCLUSIONS

This study showed that at 6-12 days post-laser myringotomy, type III and IV collagen has replaced the collagen type II that normally constitutes the healthy tympanic membrane. There is a concern for excessive scarring involving adjacent structures. It was also seen that the combination of Gelfoam and granulocyte colony-stimulating factor or saline did not affect the healing times in perforated tympanic membranes. No significant results regarding the inflammatory cell recruitment could be obtained on the studied time points or between experimental and control ears, except for in the Gelfoam matrix.

OTO-104: a sustained-release dexamethasone hydrogel for the treatment of otic disorders

HYPOTHESIS

To investigate whether OTO-104, a poloxamer-based hydrogel containing micronized dexamethasone for intratympanic delivery, can provide long-lasting inner ear exposure and be well tolerated.

METHODS

OTO-104 was administered intratympanically to guinea pigs and sheep, and its pharmacokinetic and toxicity profiles were examined.

RESULTS

After a single intratympanic injection of OTO-104 (from 0.6% to 20%, w/w), significant and prolonged exposure to dexamethasone in the inner ear was observed. Increasing the concentration of OTO-104 resulted in higher perilymph drug levels as well as a more prolonged duration of exposure. At the highest dose, therapeutic perilymph levels of dexamethasone could be sustained over 3 months in guinea pigs and more than 1 month in sheep. A toxicologic evaluation was conducted, including assessments of middle and inner ear function and physiology, as well as appraisal of local and systemic toxicity. A small and transient shift in hearing threshold was observed, most probably conductive in nature. No significant histologic changes in middle or inner ear tissues were noted. Although macroscopically mild erythema/inflammation was documented in a subset of guinea pigs treated with 20% OTO-104, the nature and the severity of these changes were not different between the poloxamer vehicle, saline, and 20% OTO-104 groups. No evidence of acute dermal toxicity, delayed hypersensitivity, or systemic adverse effects was found.

CONCLUSION

OTO-104 is a novel proprietary therapeutic delivery system that can achieve prolonged, sustained release of dexamethasone within the inner ear fluids. The administration of this clinical candidate formulation via intratympanic injection is expected to be well tolerated both locally and systemically.

Effects of NasoPore Packing in the Middle Ear Cavity of the Guinea Pig

Objective. To evaluate the effects of NasoPore after packing of the middle ear in guinea pigs.

Study Design. A randomized, prospective, controlled animal study.

Setting. University laboratory.

Subjects and Methods. Forty-one guinea pigs were divided into 3 groups. In group 1 (n = 12), the middle ears of animals were unilaterally implanted with NasoPore, leaving the contralateral middle ears packed with absorbable gelatin sponge soaked in a solution containing kanamycin and furosemide as an ototoxicity-positive control; group 2 (n = 17) underwent the same experimental protocol as group 1, except the gelatin sponge was unsoaked; in group 3 (n = 12), NasoPore was inserted unilaterally and no packing material was placed into the contralateral ear. Auditory brainstem responses (ABRs) were performed preoperatively and 3 months after the procedure. The surface preparation and scanning electron microscopy (SEM) were assessed 3 months postoperatively, whereas pathology of middle ear was analyzed in 5 samples of group 2.

Results. ABR thresholds of the contralateral ear significantly increased in group 1 and were slightly shifted in group 2 compared with the NasoPore-packed and nonpacked ears 3 months postoperatively. The NasoPore-packed middle ears were found to have less fibrosis and inflammation and less thickened bone and tympanic membranes than Gelfoam-packed ears. Surface preparations and SEM showed no ototoxicity in the inner ear of NasoPore-packed ears.

Conclusion. NasoPore appears to be effective for use in otosurgery. It caused less fibrosis in the middle ear than conventional packing agents and no ototoxicity to the inner ear.