To pack or not to pack? A contemporary review of middle ear packing agents

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.

Hyaluronic Acid Gel as Middle Ear and External Auditory Canal Packing Material in Tympanoplasty

OBJECTIVE

This study aims to evaluate the effect of hyaluronic acid gel (HAG) on tympanic membrane (TM) graft success rate and audiometric outcomes in patients with large TM perforations during tympanoplasty.

STUDY DESIGN

A single-blinded randomized controlled trial.

SETTING

Tertiary hospital.

METHODS

In the study, we performed tympanoplasty via postauricular approach on 488 ears and compared 2 groups: the control group (n = 247) with absorbable gelatin sponge packing and the HAG group (n = 241) with HAG packing in both the middle ear and medial 2/3 of the external auditory canal. We compared the graft success rates and postoperative audiometric outcomes between the 2 groups.

RESULTS

In a study of 488 ears (HAG group = 241, control group = 247), the HAG group had a higher graft success rate of 96.7% (233/241 ears) compared to the control group's 91.5% (226/247 ears; P = .015). No significant difference was observed between HAG and control in postoperative ABG closure within 20 dB (HAG: 66.8% or 161 ears; control: 59.1% or 146 ears; P = .078). There were no significant differences in improvements, compared to their preoperative condition, in mean bone conduction (HAG: -0.1 ± 6.5; control: 1.3 ± 7.6), air conduction (HAG: 8.7 ± 12.1; control: 9.7 ± 13.1), air-bone gap (HAG: 8.8 ± 10.6; control: 8.4 ± 12.0), and speech reception threshold (HAG: 9.4 ± 11.8; control: 9.2 ± 13.5) between the control and HAG groups (two one-sided T test, P < .001).

CONCLUSION

In tympanoplasty, HAG packing in the middle ear and external auditory canal yields higher graft success rates than absorbable gelatin sponge, while audiometric outcomes are similar for both the HAG and absorbable gelatin sponge packing cohorts.

Bacteriostatic effect of Ag@TiO2-Poly(p-dioxanone)-coated gauzes in vitro and in vivo on otitis media pathogens

The application of packing agents affects the final surgical outcomes in treating otitis media (OM) and introduces the risk of infection. To decrease the infectious risks of packing agents and even introduce positive bacteriostatic functions, a kind of PPDO-grafted Ag-incorporated TiO2 nanoparticles (Ag@TiO2-PPDO NP)-coated gauzes were prepared by a solution immersion method. Morphologies and in vitro Ag+ releasing of Ag@TiO2-PPDO NP coated gauzes were determined by scanning electron microscope (SEM) and inductively coupled plasma-mass spectrum (ICP-Ms). Ag@TiO2-PPDO NP could respond to visible light, which might make Ag@TiO2-PPDO NP inhibit the proliferation of bacteria continually and positively with irradiation of visible light. Then the bacteriostatic effects of these gauzes on OM pathogens were investigated in vitro and in vivo. These gauzes could inhibit the proliferation of pathogenic Staphylococcus aureus (S. aureus) and Streptococcus pneumoniae (S. pneumoniae) in vitro and rat subcutaneous infection models. Specifically, the bacteriostatic effect of these gauzes on S. aureus and S. pneumoniae could be enhanced with irradiation by visible light in vitro. Further, the rat external auditory canal infection model verified the enhanced bacteriostatic effect of Ag@TiO2-PPDO-coated gauzes on S. aureus with irradiation by visible light. The Ag@TiO2-PPDO-coated gauzes are promising for packing materials after OM surgery and could reduce postoperative antibiotic requirements.

Efficacy of gelfoam middle ear packing in type-1 tympanoplasty: systematic review and meta-analysis

PURPOSE

To conduct a systematic review and meta-analysis of randomized controlled trials (RCTs) that evaluated the surgical outcomes of type-1 tympanoplasty with and without gelfoam middle ear packing.

METHODS

PubMed, CENTRAL, Scopus, Web of Science, and Google Scholar databases were screened from inception until October 2022. The included RCTs were evaluated for risk of bias, and the quality of each outcome was assessed according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system.

RESULTS

Nine RCTs with 773 participants (gelfoam = 381 and non-gelfoam = 392) were analyzed. The overall study quality varied: low risk (n = 4 RCTs), some concerns (n = 3 RCTs), and high risk (n = 2 RCTs). There were no significant differences between both arms regarding the graft uptake rate (moderate certainty), hearing improvement rate (moderate certainty), type of impedance audiometry (moderate certainty), and ear discharge (low certainty). The mean change in air-bone gap was significantly higher in the non-gelfoam arm compared with the gelfoam arm (low certainty). However, the non-gelfoam group had superior hearing improvement in only the early postoperative period (i.e., one month); however, after two, three, and six months, there were no significant differences between both arms. The rate of ear fullness was significantly higher in the gelfoam arm compared with the non-gelfoam arm (moderate certainty).

CONCLUSION

Among patients undergoing type-1 tympanoplasty, the surgical outcomes did not significantly differ between both arms. The practice of middle ear packing with gelfoam needs to be standardized.

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.

Is Gelfoam Necessary for Middle Ear Surgery: A Comparative Study of the Results of Tympanoplasty With and Without Gelfoam in the Middle Ear

Absorbable gelatin sponge (Gelfoam) has been used for many years in middle ear surgeries. It not only provides support to the graft and ossicular reconstruction materials but also helps in haemostasis and aeration of the middle ear. Although gelfoam is generally well tolerated but fibrosis and granulations in the mesotympanum have been attributed to its usage in some studies. This study was conducted to compare the results of middle ear surgeries with and without gel foam in terms of both objective and subjective improvements of symptoms. To study the outcome of tympanoplasty with and without gel foam in the middle war by measuring following attributes (for measuring outcomes) at an intervals of 6 weeks, 12 weeks and 6 months after surgery. (a) Graft take up rate as evaluated by otoscopy. (b) Pre and post-operative hearing levels as measured on Pure Tone Audiogram. (c) Subjective improvement in symptoms of ear discharge, heaviness in ears, hearing loss and tinnitus. Study design-prospective clinical study. patients undergoing tympanoplasty type 1 between August 2018 to July 2019 were included in the study. Group A (n = 36) consisted of patients who underwent tympanoplasty with gel foam in the middle ear and Group B (n = 36) consisted of patients who underwent tympanoplasty without any gel foam inside the middle ear. The uptake of graft after tympanoplasty was almost similar in the patients using gelfoam (89%) and those without gelfoam (84%) at the end of 6 months. The improvement in the subjective symptoms of ear discharge and hearing loss at 6 weeks following the surgery was better in patients without gelfoam whereas, at the end of 6 months the improvement in these symptoms was similar in both the groups. The improvement in hearing 6 months following tympanoplasty as assessed by pure tone audiometry and was found to be the same in both the groups. Tympanoplasty can be performed safely without using any gelfoam in the ear. This not only makes patients comfortable early but also avoids any gelfoam induced fibrosis or granulations in the middle ear.

Feasibility of an Innovative Absorbable Ventilation Tube Designed to Provide Intermediate-Term Middle Ear Ventilation

Myringotomy with ventilation tube placement is a common surgical procedure performed in children and adults to remove fluid buildup behind the tympanic membrane. However, retention of tubes beyond achievement of therapeutic response increases risk for complications and additional intervention. This small feasibility study was conducted to demonstrate proof of concept of a novel bioabsorbable ventilation tube that provides the necessary duration of ventilation with absorption shortly thereafter. Tubes were placed in 15 ears of 14 patients meeting indications for short or intermediate duration of middle ear ventilation. Two independent examiners documented tube patency and tube absorption status at 3, 6, and 12 weeks or until absorption was complete. Results indicate that average ventilation time was 12 weeks (range, 3 weeks to 18 months). There was no observation of blockage. These findings support the feasibility of a novel bioabsorbable ventilation tube.

Efficacy of middle-ear packing in success of type 1 tympanoplasty: a prospective randomised study

OBJECTIVE

A prospective randomised study was undertaken to compare the results of type 1 tympanoplasty with and without middle-ear packing with gelfoam.

METHOD

Eighty patients undergoing type 1 tympanoplasty were randomised into two groups according to packing in the middle ear: with gelfoam and without gelfoam. The data in terms of graft uptake rate, hearing gain and subjective improvement were analysed at one and three months.

RESULTS

The graft uptake rate between both groups did not show a statistically significant difference. There was conductive hearing loss in the gelfoam group in the early post-operative period. Subjectively, patients were more comfortable with respect to heaviness and hearing gain than in the non-gelfoam group.

CONCLUSION

Gelfoam use in middle-ear packing is not an essential step and causes more discomfort in patients during the early post-operative period. It should be a surgeon's choice to use it when and where it is necessary.

Prospective Comparison of Pediatric Endoscopic Lateral Graft and Interlay Tympanoplasty

OBJECTIVE

To compare outcomes and complications of endoscopic lateral graft (LGT) and interlay (IT) tympanoplasty.

STUDY DESIGN

Prospective observational cohort study of totally endoscopic ear surgery (TEES) tympanoplasty.

SETTING

Pediatric tertiary referral center.

PATIENTS

One hundred fourteen surgeries for children with tympanic membrane perforation without cholesteatoma.

INTERVENTION

Porcine-derived collagen graft tympanoplasty using either LGT or IT.

MAIN OUTCOME MEASURES

Closure rates of perforation, hearing outcomes (four-tone average air conduction [AC] and air bone gap), and complications that required further surgery were assessed 12 months postoperatively.

RESULTS

Perforation closure rates did not differ between LGT (52/59 (88%)) and IT (45/51 (88%)), (Fisher's exact p = 1.00) (four ears lost to follow-up). AC thresholds (p = 0.32) and air bone gap (p = 0.88) improved similarly after surgery with LGT (median 8.8 dB) and IT (median 7.5 dB). The proportion of ears with serviceably normal hearing (AC ≤ 30 dB HL) postoperatively was similar (LGT 40/49 (82%), IT 36/46 (78%), Fisher's exact p = 0.80). Following IT, three (6%) ears developed inclusion cholesteatoma requiring revision surgery. One (2%) LGT ear developed blunting after myringitis.

CONCLUSIONS

IT and LGT provide similar perforation closure rates and hearing outcomes. When choosing between these two techniques to repair pediatric tympanic membrane perforations, LGT would seem to be preferable than IT due to the risk of inclusion cholesteatoma after IT. There is a small risk of anterior blunting after LGT.

Efficacy of Topical Epinephrine in Tympanoplasty

OBJECTIVES/HYPOTHESIS

To compare the hemostatic effects of commonly used concentrations of topical epinephrine in tympanoplasty.

STUDY DESIGN

Prospective, randomized, controlled clinical trial.

METHODS

Patients undergoing tympanoplasty were randomized to receive topical epinephrine at 1:1,000 or 1:10,000. With the investigators blinded, hemostasis was assessed with a modified Boezaart scale. Vasoconstriction was measured by laser Doppler. Blood pressure and pulse were tracked.

RESULTS

Thirty patients, 4 to 84 years old, were studied, with 15 patients per group. Boezaart scores dropped a mean of 67% and 62% with 1:1,000 and 1:10,000, respectively (P = .44). Capillary blood flow decreased a mean of 50.4% and 50.9% with 1:1,000 and 1:10,000, respectively (P = .95). The mean change in heart rate and mean arterial pressure after topical epinephrine exposure were -4.9 and -0.73 beats per minute (P = .15), and -0.60 and -0.73 mmHg (P = .96) for 1:1,000 and 1:10,000 respectively. No adverse events occurred in either group.

CONCLUSIONS

Topical epinephrine at 1:10,000 has hemostatic efficacy comparable to 1:1,000 in tympanoplasty. Although both concentrations appear safe, use of topical epinephrine 1:10,000 should be considered over 1:1,000 to minimize the potential for adverse events.

LEVEL OF EVIDENCE

2 Laryngoscope, 2021.

Necessities, opportunities, and challenges for tympanic membrane perforation scaffolding-based bioengineering

Tympanic membrane (TM) perforation is a global clinical dilemma. It occurs as a consequence of object penetration, blast trauma, barotrauma, and middle ear diseases. TM perforation may lead to otitis media, retraction pockets, cholesteatoma, and conductive deafness. Molecular therapies may not be suitable to treat perforation because there is no underlying tissue matrix to support epithelium bridging. Chronic perforations are usually reconstructed with autologous grafts via surgical myringoplasty. Surgical treatment is uncomfortable for the patients. The grafting materials are not perfect because they produce an opaque membrane, fail in up to 20% of cases, and are suboptimal to restore acoustic function. Millions of patients from developing parts of the world have not got access to surgical grafting due to operational complexities, lack of surgical resources, and high cost. These shortcomings emphasize bioengineering to improve placement options, healing rate, hearing outcomes, and minimize surgical procedures. This review highlights cellular, structural, pathophysiological, and perforation specific determinants that affect healing, acoustic and surgical outcomes; and integrates necessities relevant to bioengineered scaffolds. This study further summarizes scaffolding components, progress in scaffolding strategies and design, and engenders limitations and challenges for optimal bioengineering of chronic perforation.

Acellular Collagen Scaffold With Basic Fibroblast Growth Factor for Repair of Traumatic Tympanic Membrane Perforation in a Rat Model

OBJECTIVE

To evaluate the efficacy of acellular collagen scaffold (ACS) in combination with basic fibroblast growth factor (bFGF) for the repair of traumatic tympanic membrane (TM) perforation in a rat model.

STUDY DESIGN

A prospective controlled animal study in a rat model of traumatic TM perforation.

SETTING

Tertiary medical center.

SUBJECTS AND METHODS

Sprague-Dawley rats (N = 84) with unilateral traumatic perforation of the right TMs were randomized to receive ACS, bFGF, ACS in combination with bFGF (ACS/bFGF), or nothing (spontaneous healing without any interventions as a control group). The healing outcomes were evaluated by otoscopy, optical coherence tomography, histology, and transmission electron microscopy at 1, 2, and 4 weeks postoperatively. The hearing outcomes were assessed with auditory brainstem response testing.

RESULTS

ACS/bFGF resulted in higher perforation closure rates at an earlier stage than spontaneous healing, ACS, and bFGF. Based on histology, optical coherence tomography, and transmission electron microscopy, a trilaminar structure and uniform thickness with mature, densely packed collagen fibers were seen in the ACS/bFGF group. Auditory brainstem response evaluation also showed that ACS/bFGF treatment promoted faster functional hearing recovery as compared with the control group.

CONCLUSIONS

ACS is an effective TM scaffold and a carrier for bFGF. ACS/bFGF improves the TM closure rate, results in better-reconstructed TMs, and improves hearing. ACS/bFGF serves as a potential substitute for TM perforations in clinical settings.

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.

Comparison of functional outcomes of cartilage tympanoplasty with silastic sheet versus Gelfoam packing in middle ear

BACKGROUND AND AIM

Tympanoplasty is a common surgery in otorhinolaryngology field. In majority of procedures, in addition to the graft used for closure of tympanic membrane, a packing material is essential to be placed in the middle ear cavity. The main goals of packing can be summarized as providing support to the tympanic membrane and ossicular grafts, aeration of middle ear cavity and hemostasis. Several packing materials are currently available for using in middle ear surgeries. Each agent is associated with particular advantages and disadvantages, so choosing the proper packing agent is essential in tympanoplasty surgeries. In this study we aimed to compare two common packing materials (Gelfoam and silastic sheets) in cartilage tympanoplasty surgeries.

METHODS AND MATERIALS

In this block-randomized clinical trial, 78 patients undergoing tympanoplasty in Vali-e-asr hospital in 2017 and 2018 were enrolled. They were randomly assigned to silastic sheet or gelfoam groups. The functional outcomes were compared between the groups. Statistical analysis was performed by SPSS.

RESULTS

Success was achieved in 32 (82.1%) patients and 34 (87.2%) patients in gelfoam and silastic sheets' groups, respectively (p = 0.530). The perforation area percentage was significantly lower (P = 0.007) in Gelfoam group. The other parameters were statistically the same in both groups (P > 0.05).

CONCLUSION

Overall, Gelfoam and silastic sheet methods had similar efficacy in cartilage tympanoplasty. Using each method depends on the preferrence of surgeon and patients' characteristics. Multi-center studies with larger sample sizes are needed for more conclusive results.

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.

Safety and Efficacy of Chitosan-Dextran Hydrogel in the Middle Ear in an Animal Model

OBJECTIVES

To investigate the efficacy of chitosan-dextran hydrogel (CDH) in preventing postoperative adhesions between the tympanic membrane (TM) and intratympanic structures, and to evaluate its ototoxicity in an animal study.

METHODS

In the first step, ototoxicity was evaluated with 7 male albino guinea pigs (GPs) via auditory brainstem responses (ABR) before and 4 weeks after unilateral intratympanic injection of CDH and saline solution contralaterally. In the second step, 12 GPs underwent bilateral ear surgery. The middle ear (ME) mucosa was abraded, and the cavity was filled with CDH on one side and packed with Gelfoam on the contralateral side. A control group of 6 GPs underwent the same procedure except that no material was applied in the ME. The animals were euthanized at the end of the 7th week, and otomicroscopic findings were noted and the temporal bones harvested for the histologic examination. The findings were scored and compared.

RESULTS

There was no statistically significant difference between the pre- and postoperative ABR thresholds. In the otomicroscopic findings, the most prominent difference between the two groups was the presence of retraction of the TM in the Gelfoam group. The histopathologic findings revealed a higher degree of inflammation in the Gelfoam group compared with the CDH group.

CONCLUSION

This study demonstrated that CDH has no ototoxic effects in GPs. Its use as an ME packing material revealed significantly less TM retraction and inflammatory reaction compared with Gelfoam.

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.

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.

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.

The biocompatibility of silk fibroin and acellular collagen scaffolds for tissue engineering in the ear

Recent experimental studies have shown the suitability of silk fibroin scaffold (SFS) and porcine-derived acellular collagen I/III scaffold (ACS) as onlay graft materials for tympanic membrane perforation repair. The aims of this study were to further characterize and evaluate the in vivo biocompatibility of SFS and ACS compared with commonly used materials such as Gelfoam and paper in a rat model. The scaffolds were implanted in subcutaneous (SC) tissue and middle ear (ME) cavity followed by histological and otoscopic evaluation for up to 26 weeks. Our results revealed that SFS and ACS were well tolerated and compatible in rat SC and ME tissues throughout the study. The tissue response adjacent to the implants evaluated by histology and otoscopy showed SFS and ACS to have a milder tissue response with minimal inflammation compared to that of paper. Gelfoam gave similar results to SFS and ACS after SC implantation, but it was found to be associated with pronounced fibrosis and osteoneogenesis after ME implantation. It is concluded that SFS and ACS both were biocompatible and could serve as potential alternative scaffolds for tissue engineering in the ear.

Tympanic membrane repair using silk fibroin and acellular collagen scaffolds

OBJECTIVES/HYPOTHESIS

To evaluate the efficacy of silk fibroin scaffolds (SFS) and acellular collagen scaffolds (ACS) for the repair of tympanic membrane (TM) in a guinea pig acute perforation model.

STUDY DESIGN

Experimental animal research.

METHODS

Seventy-two albino guinea pigs underwent perforation of the right TM and were divided into four experimental groups (n = 18). The perforations were repaired with SFS, ACS, and paper patch using onlay myringoplasty, or they were allowed to heal spontaneously (control). An additional group of 10 guinea pigs without perforation or scaffold was allocated as a normal TM group. Guinea pigs in each experimental group (n = 6) were evaluated at 7, 14, and 28 days following surgery. TM structural healing was evaluated by otomicroscopy and histology, and functional hearing was analyzed by auditory brainstem responses (ABR). Prior to the study, mechanical properties of SFS and ACS were investigated.

RESULTS

Tensile strength and elasticity of SFS and ACS were within the known range for human TM. Based on otologic and histologic evaluation, TMs treated with SFS or ACS showed complete closure of the perforation at an earlier stage, with a trilaminar structure and more uniform thickness compared to paper patch and control treated groups. ABR assessment demonstrated that SFS or ACS treatment facilitated a faster restoration of hearing function compared to paper patch and control groups.

CONCLUSION

The results of this study show that SFS and ACS are effective graft materials and may be utilized as alternatives to current grafts for TM repair.

Factors affecting hearing improvement following successful repair of the tympanic membrane

BACKGROUND

The main aim of tympanic membrane repair is the elimination of chronic or intermittent aural discharge. Hearing improvement may or may not occur following a technically successful operation.

METHOD

This study entailed a retrospective analysis of prospectively collected data from 203 operations that resulted in an intact tympanic membrane 6 months after surgery.

RESULTS

Complete hearing data were available for 169 operations on 160 patients. Of these, 53 per cent resulted in closure of the air-bone gap to within 10 dB, and 54 per cent of cases had post-operative hearing thresholds of at least 30 dB. The mean hearing change after surgery was +8.3 dB. Multiple regression analysis indicated that hearing improvement was more likely in large compared with small perforations. Smaller hearing gains occurred in ears with erosion of the stapes arch and/or fixation of the stapes, as well as in those with active discharge at the time of surgery and in revision cases.

CONCLUSION

Greater hearing improvement can be expected following successful repair of perforations involving more than 50 per cent of the drum area. Poorer results are likely to occur in ears with additional middle-ear pathology and in revision cases.

Scaffolds for tympanic membrane regeneration in rats

Tympanic membrane (TM) perforations lead to significant hearing loss and result in possible infection of the middle ear. Myringoplasty is commonly performed to repair chronic perforations. Although various grafts and materials have been used to promote TM regeneration, all have associated limitations. The aim of this study was to evaluate the efficacy and feasibility of two graft materials, silk fibroin scaffold (SFS) and porcine-derived acellular collagen type I/III scaffold (ACS), compared with two commonly used graft materials (paper patch and Gelfoam) for the promotion of TM regeneration. These scaffolds were implanted using on-lay myringoplasty in an acute TM perforation rat model. Surface morphology of the scaffolds was observed with scanning electron microscopy. The morphology of the TM was assessed at various time points postimplantation using otoscopy, light and electron microscopy, and functional outcomes by auditory brainstem responses. We found that SFS and ACS significantly accelerated the TM perforation closure, obtained optimal TM thickness, and resulted in better trilaminar morphology with well-organized collagen fibers and early restoration of hearing. However, paper patch and Gelfoam lost their scaffold function in the early stages and showed an inflammatory response, which may have contributed to delayed healing. This study indicates that compared with paper patch and Gelfoam, SFS and ACS are more effective in promoting an early TM regeneration and an improved hearing, suggesting that these scaffolds may be potential substitutes for clinical use.

Tissue engineering of the tympanic membrane

Tympanic membrane (TM) perforations are common, with current treatments for chronic perforations involving surgery, using various graft materials, from autologous cartilage or fascia through to paper patch. Recent research developments in this field have begun applying the principles of tissue engineering, with appropriate scaffolds, cells, and bioactive molecules (BMs). This has revolutionized the therapeutic approach due to the availability of a wide range of materials with appropriate compatibility and mechanical properties to regenerate the membrane acoustics and may also represent a paradigm shift in the management of TM perforations in an outpatient setting without surgery. However, many factors need to be considered in the fabrication of a bioengineered TM. This review discusses the issues associated with current treatment and examines TM wound healing relevant to the construction of a bioengineered TM. It also describes the tissue-engineering approach to TM regeneration by summarizing currently used scaffolds, BMs, and cells in TM wound healing. Finally, it considers the design of scaffolds, delivery of BMs, and cell engraftment toward potential clinical application.

Ten top considerations in pediatric tympanoplasty

Tympanoplasty in children poses some different challenges from the same procedure in adults. The aim of the current article is to review 10 important considerations in pediatric tympanoplasty that focus on these differences and help to optimize the chance of successful outcome.