The effect of gelfilm in the prevention of fibrosis in the middle ear of the animal model

HYPOTHESIS: Gelfilm offers protection against fibrosis in the middle ear when used in combination with Gelfoam. BACKGROUND: Gelfoam is used routinely as a support structure in the middle ear cleft when ossicular reconstruction and tympanic membrane grafts are performed. It has been recognized that fibrosis may occur in this setting if the middle ear mucosa is denuded. Materials have been used to protect the mucosa in an attempt to prevent scar bands, adhesions, and fibrosis and its potential detriment on hearing. These materials have included Teflon, Silastic, and Gelfilm. Concerns have arisen regarding this mode of therapy and its benefit. METHODS: This study looks at the effects of implanting Gelfoam independently and Gelfoam and Gelfilm concurrently in the bulla cavity of the Mongolian Gerbil. The temporal bones were harvested and evaluated histologically using hemotoxylin and eosin staining for fibrosis. RESULTS: Results demonstrated a decrease in the amount of fibrosis in the animals in which Gelfilm was used to protect the denuded mucosa. No evidence of fibroblast ingrowth or scar bands penetrating the Gelfilm was identified. CONCLUSION: These results suggest that Gelfoam can be used safely in the middle ear cleft to support ossicular prosthesis and tympanic membrane grafts when Gelfilm is used to protect denuded mucosa.     

The effect of Interceed for reducing adhesion as a middle ear packing agent: an experimental study

BACKGROUND AND OBJECTIVE: Interceed (oxidized regenerated cellulose) has been used to prevent postoperative abdominal adhesion. However, the efficacy and safety of using Interceed in middle ear surgery have not been thoroughly studied. MATERIALS AND METHODS: The animals were divided into two groups: the Interceed group and the Gelfoam (Gelatin sponge) group. In every group, the study was performed on five guinea pigs (ten ears). Under the aseptic condition, the middle ear mucosa was abraded using a pick through a myringotomy incision. Interceed and Gelfoam were then packed into the guinea pigs' middle ear cavities. The auditory brainstem responses (ABRs) were assessed preoperatively and at 3 weeks after the operation with the animals under general anesthesia. Histopathologic study was performed 3 weeks after the operation. RESULTS: The ABR results on postoperative week 3 showed no statistically significant difference for myringotomy and postpacking. The fibrosis, middle ear mucosa thickening and adhesion formation appeared to be less in the Interceed group compared with the Gelfoam group. Any foreign body reaction was not observed in the Interceed group. CONCLUSION: Our results show that Interceed is nonototoxic and biocompatible with the guinea pig's middle ear cavity. Therefore, these results suggest that Interceed could be used safely in the middle ear as a middle ear packing agent during otosurgery.     

Does occurrence of keratinizing stratified squamous epithelium in the middle-ear cavity always indicate a cholesteatoma?

The origin and behaviour of keratinizing stratified squamous epithelium, an essential component of cholesteatoma occurring in the middle-ear cavity, has puzzled otologists for decades. In this experimental study in 16 cats, central (n = 23) and peripheral (n = 9) tympanic membrane perforations were observed for up to 63 days before sacrifice. The tympanic membranes with bony rim were excised, decalcified and embedded in Epon 812. Sections were stained with toluidine blue and examined using a light microscope. The perforation had been sealed by meatal epithelium exhibiting pronounced hyperplasia and keratin formation, lying on a bed of granulation tissue. Subtotal central perforations healed within 14 days, forming a bowl-shaped tympanic membrane and leaving parts of the handle of the malleus (with meatal epithelium) protruding freely into the middle-ear cavity. Stratified squamous epithelium, morphologically identical with that of external ear canal epidermis, could be observed on the malleus even 63 days after operation. This meatal epithelium was non-keratinizing, non-invasive, and showed no destructive properties typical of acquired cholesteatoma. During certain circumstances, the cell cycle of hyperplastic epidermal epithelium within the middle-ear cavity can evidently be arrested and inactivated by a local defence mechanism.     

Acoustic responses of the human middle ear

Measurements on human cadaver ears are reported that describe sound transmission through the middle ear. Four response variables were measured with acoustic stimulation at the tympanic membrane: stapes velocity, middle-ear cavity sound pressure, acoustic impedance at the tympanic membrane and acoustic impedance of the middle-ear cavity. Measurements of stapes velocity at different locations on the stapes suggest that stapes motion is predominantly ‘piston-like’, for frequencies up to at least 2000 Hz. The measurements are generally consistent with constraints of existing models. The measurements are used (1) to show how the cavity pressure and the impedance at the tympanic membrane are related, (2) to develop a measurement-based middle-ear cavity model, which shows that the middle-ear cavity has only small effects on the motion of the tympanic membrane and stapes in the normal ear, although it may play a more prominent role in pathological ears, and (3) to show that inter-ear variations in the impedance at the tympanic membrane and the stapes velocity are not well correlated.     

Topical ascorbic acid reduces myringosclerosis in perforated tympanic membranes. A study in the rat.

Myringosclerosis, a common finding after myringotomy, has been recently associated with an increased production of oxygen free radicals. Ascorbic acid's proposed actions include collagen synthesis, antioxidation, and free radical scavenging. The effects of topical ascorbic acid on healing tympanic membranes were studied. Particular attention was given to detecting the presence of myringosclerosis. Twelve Sprague-Dawley rats were bilaterally myringotomized. Their ears were randomized into group A, which received topical ascorbic acid in Gelfoam, group B, which received topical saline solution in Gelfoam, and group C, which received no treatment. The tympanic membranes were harvested on day 13, after routine otomicroscopy. Under light microscopy, the connective tissue layer of the untouched side of the pars tensa was distinctly thicker in group A than in group B or group C. At this level, the extent of sclerotic lesions was significantly less in the ascorbic acid-treated group. It is inferred that topical ascorbic acid reduces the occurrence of myringosclerosis following tympanic membrane perforations in the rat.     

Canal wall down tympanoplasty with canal reconstruction for middle-ear cholesteatoma: post-operative hearing,cholesteatoma recurrence,and status of re-aeration of reconstructed middle-ear cavity

The post-operative outcome of hearing, the reconstructed external auditory canal, and the state of the reconstructed middle-ear cavity after canal wall down tympanoplasty with canal and attico-antrum reconstruction was studied in 103 ears with middle-ear cholesteatoma. The reconstructed mastoid cavity was re-aerated in 36.5 per cent of the cases, which was significantly lower than for the epitympanum (63.5 per cent) and tympanic cavity (82.4 per cent). Tympanoplasty was successful in terms of hearing results in 68.9 per cent of all subjects and in 75.4 per cent of the ears having a re-aerated tympanic cavity, which was significantly better than the 38.5 per cent for ears in which the tympanic cavity was not re-aerated. The findings of recurrent cholesteatoma, tympanic atelectasis, and tympanic effusion were observed with significantly (p<0.03) high incidence in ears with no re-aerated space in their reconstructed mastoid cavities. It was revealed that the post-operative outcome of this surgical technique was significantly related to the state of re-aeration of the reconstructed middle-ear cavity.     

Myringotomy: A Prerequisite for the Development of Myringosclerosis?

Streptococcus pneumoniae was inoculated into the left middle-ear cavity in two groups of rats, resulting in purulent otitis media. After 3 days, one group of infected animals and a third group of noninfected animals were subjected to left-sided myringotomy. The tympanic membranes were examined both otomicroscopically and histologically 1 and 3 months later. On otomicroscopic examination the noninfected myringotomized animals had developed extensive myringosclerotic lesions, whereas only minimal sclerotic deposits were noted in the myringotomized animals with acute otitis media (AOM). On histologic examination both the noninfected myringotomized animals and the myringotomized animals with AOM were similar in the frequency and extension of sclerotic lesions in the tympanic membrane. The nonmyringotomized rats with AOM were free of sclerotic lesions, except for minor changes found in one animal.     

Absorbable gelatin sponge (Gelfoam) in otosurgery: one cause of undesirable postoperative results?

Absorbable gelatin sponge (Gelfoam)--commonly used in otosurgery--was gently inserted or firmly packed into the middle ear cavities of rats. The postoperative changes were evaluated 2 to 3 months later when, apart from some air-filled canals leading from the tympanal orifice of the Eustachian tube towards the attic, the middle ear cavity had become filled with newly formed bone and an amorphous mass of adhesions and bridles. The mass consisted of loose connective tissue, with fibroblasts, vessels and inflammatory cells. The tympanic membrane was retracted and fixed to the promontory. There were no signs that any Gelfoam had been removed through the Eustachian tube. The authors proposed that similar tissue reactions may occur in tympano-plasties.     

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.     

Homografts of the tympanic membrane with malleus; histological study in cat

The present experiments on cats were performed to explore the process of survival and take of transplanted homografts of tympanic membrane with malleus, the homografts being respectively preserved in 4% and 0.5% formalin (pH 7.0) solutions, and to explore the reaction of middle ear mucosa of the recipient. The present study also included gross and histopathological examinations of the eardrum and observation of fibers of the lamina propria of the transplanted tympanic membrane by means of polarizing microscopy and of vascularization by intravascular India ink injection. The experiments conducted using a total of 96 cats yielded results leading to the following conclusions. 1) After six months the transplanted tympanic membrane showed nearly normal histologic features, with a fibrous layer between the lining epithelial and thin mucosal layers. The middle ear mucosa also became thinner and was covered with ciliated epithelium at this stage. 2) As regards vascular distribution, most vessels entered from the peripheral regions to become distributed all over the eardrum with mutual anastomoses. 3) Fibrous tissues of the lamina propria of the pars tensa of the transplanted eardrum remained intact over the six month period. 4) The transplanted malleus was neither destroyed not absorbed, and proved to survive well with active vascularization. 5) The microscopic changes observed in the middle ear mucous membrane of the recipient showed non-specific reactions to Gelfoam. The grafts were not subjected to immunological rejection. Homograft thus offer the best grafting material, but seemed to show poor resistance to infection.     

碱性成纤维细胞生长因子对豚鼠中耳放射性损伤的防护作用

目的通过观察碱性成纤维细胞生长因子(basic fibroblast growth factor,bFGF)对豚鼠放射性损伤侧中耳黏膜的病理和超微结构变化的影响,探讨bFGF对中耳放射性损伤有无保护作用及其作用机制。方法选用标准清洁级成年白色红目雄性豚鼠44只,随机分为正常对照组、模型对照1天组、模型对照30天组、bFGF1天组、bFGF 30天组共5组。取鼓室内黏膜及咽鼓管(eustachian tube,ET),作病理切片观察中耳黏膜的病理改变情况及扫描电镜观察中耳黏膜纤毛损伤程度,并用医学图像分析软件测量咽鼓管、鼓室前壁(tympanic cavity anterior wall,TCAW)、鼓岬(promontorium tympani,PT)黏膜的厚度。结果①中耳标本大体观察:bFGF 1天组及30天组鼓膜均完整,仅见中耳黏膜稍充血、水肿;②中耳黏膜厚度改变结果:bFGF 1天及30天组与模型对照组比较咽鼓管、鼓室前壁、鼓岬的黏膜厚度明显较薄,P均<0.01,差异有显著性;③扫描电镜观察结果:bFGF 1天及30天组黏膜上皮纤毛方向基本一致,仅尖端有轻微倒伏、粘连。结论bFGF能明显减轻电离辐射对中耳黏膜的损伤,减轻炎症反应,抑制纤维化,保护中耳功能。     

Langzeitbeobachtungen chronischseröser Otitis media nach experimentellem Tubenverschluß bei Katzen

Summary In order to induce a serous otitis media in cats, the pharyngeal opening of the Eustachian tube was cauterized and obstructed on one side only through transpalatal approach; the other side remaind intact and served as control. On tympanic membrane examination and puncture 11 months later, there was fluid in the middle ear in three ears, no fluid in two ears, a tympanic membrane perforation in one ear and a red tympanic membrane in one ear. The middle ear was then ventilated through a plastic tube in two ears with and without fluid respectively. In all other ears, no tube was inserted. After another 7 months, the animals were intravitally perfused, and the middle ear mucosa biopsyed. The histological results of the light and electron microscopy showed chronic changes of the middle ear mucosa following experimental tubal obstruction.     

Early postoperative middle-ear ventilation -- risk for the transplant or guarantee for aeration of the tympanic cavity?

BACKGROUND: Sufficient ventilation of the tympanic cavity is a decisive factor for the success of the therapy and the prognosis after tympanoplastic surgery. With the postoperative use of the Valsalva- and Politzer-maneuver the patient is able to influence the aeration of the tympanic cavity in a positive way by autoinsufflation. However this implicates the risk of a dislocation of the transplant, which is possibly caused by high middle-ear pressure-peaks during the maneuvers mentioned. METHODS: The actual increase of pressure in the tympanic cavity respectively auditory canal during the Valsalva- and Politzer-maneuver is examined in 22 patients with chronic-mesotympanic Otitis media and additionally by using an experiment with a model of a reconstructed middle-ear. The risk of a transplant-dislocation after tympanoplasty type I is estimated. RESULTS: The increase of pressure in the middle ear respectively auditory canal -- and with that the possibility of a dislocation of the transplant -- is lower after Politzer- compared with Valsalva-maneuver. If the transplant is secured through silicon sheets and packings in the auditory canal, the probability of "blowing away" the newly created cover of the tympanon will be very small. CONCLUSIONS: Because of the benefits for the aeration of the tympanic cavity, an early post-operative insufflation of the middle-ear -- using the Politzer- and/or "cautious" Valsalva-maneuver -- is recommended.     

The release of histamine from the pars flaccida mast cells one cause of otitis media with effusion?

In this experimental study in the rat, compound 48/80--a potent degranulating drug of mast cells--was instilled in the external auditory meatus towards the tympanic membrane. Moreover, effusion material was produced in the attic space by blocking the tympanic isthmus with a piece of Gelfoam applied through the tympanic bulla. Both these procedures caused a degranulation of the pars flaccida mast cells and subsequently histamine was detected in the rinsing fluid collected from the middle ear cavity. A possible direct cause of the effusion material in the middle ear cavity may be a degranulation of the pars flaccida mast cells, thus resembling an allergic reaction Type I.     

The effect of platelet-rich fibrin membrane on the repair of perforated tympanic membrane: an experimental study

Conclusion: Platelet-rich fibrin (PRF) membrane could be used successfully in the repair of tympanic membrane perforation and wound healing.

Objectives: To evaluate the effect of platelet-rich fibrin membrane in the repair of perforated tympanic membrane.

Methods: After otoscopic examination, a 3-mm perforation was made in the posterior quadrant of both tympanic membranes of 50 adult male Sprague-Dawley rats. Venous blood was withdrawn from the rats, then centrifuged. PRF was obtained in membrane form. The membrane was placed on the right tympanic membrane perforation. The perforations on the left side were left to spontaneously heal and, thus, formed the control group. Daily examinations were made of 20 rats and the time to healing of the tympanic membrane was recorded. The remaining 30 rats were separated into five groups of six, and histopathological examination was made. Evaluation was made in respect of the presence of oedema in the lamina propria, neovascularization, fibroblastic reaction, and inflammatory cells.

Results: The healing time of the tympanic membrane perforation was determined as mean 10.3?±?2.18 days in the study group applied with PRF and 17?±?2.40 days in the control group. Higher values in respect of fibrosis and neovascularization were obtained in the study group.     

Long-term effects of Silastic sheeting in the middle ear.

Silastic sheeting is used to restore a mucosally lined middle ear space and to prevent mucosal adhesions between the medial surface of the tympanic membrane and the promontory after surgical procedures involving the removal of middle ear mucosa. To determine the long-term (1.2 to 21.2 years) effects of Silastic sheeting in the middle ear, six temporal bones from patients with permanent Silastic sheeting in the middle ear cavity after single-stage tympanoplasty were examined. In all six bones, no histologic evidence of foreign body reaction, rejection, or chronic inflammation in the middle ear surrounding the silicone sheeting was observed. Furthermore, the middle ear space was lined by normal-appearing, continuous middle ear mucosa. In four temporal bones, there was no evidence of significant submucosal fibrosis. In two bones, significant submucosal fibrosis was attributable to concurrent middle ear disease rather than to the presence of the silicone. It is concluded that Silastic sheeting in the middle ear after single-stage procedures may prevent adhesions between mucosal surfaces. Given eustachian tube function, Silastic promotes a mucosally lined, aerated middle ear cavity without apparent foreign body reaction, rejection, or chronic inflammatory response.     

Behandlung von Trommelfellperforationen mit Fibringel

Background

The goal of this study was to evaluate the effects of a fibrin gel on the healing of tympanic membrane perforation in rats.

Methods

Prolonged tympanic membrane perforations in 12 rats were created by application of mitomycin C to the intact tympanic membranes followed by bilateral myringotomy. Repeated applications of a fibrin gel to the perforation site of one tympanic membrane were performed in each animal. Tympanic membranes were observed for a total of 8 weeks.

Results

One perforation in each group was already patent at the end of the observation period. The mean healing period of the remaining tympanic membranes was found to be 16.7 days in the fibrin gel group and 19.6 days in the control group.

Conclusion

A fibrin sheet does not seem to promote the wound healing process of tympanic membranes. However, the sheet might serve as a drug-delivery system for growth factors in the treatment of tympanic membrane perforations, because of its biocompatibility.     

The effect of Nigella sativa oil on prevention of myringosclerosis in a Guinea pig model

ObjectivesIn this study, our aim was to identify the possible effects of Nigella sativa L. (NS) [blackcumin] seed oil on the prevention of experimentally induced myringosclerosis (MS).Materials and methodsFourteen Guinea pigs were used and they were divided into three groups. Tympanic membranes (TM) of all animals were perforated and then group I was treated with saline soaked gel foams as a control group, group II was treated with 0.5 ml NS oil soaked gel foams at 0, 24 and 48 h and group III was treated with 5 ml NS oil orally at 0, 24, 48, 72 and 120 h. After 15 days, all animals were euthanized. Tympanic membranes were evaluated macroscopically and histopathologically.ResultsGroups I showed extensive myringosclerosis in contrast to those of Groups II and III which had significantly less changes (p < 0.05). The fibrosis and inflammation in the lamina propria of the tympanic membranes of Groups I was found to be significantly more pronounced (p < 0.05). The tympanic membranes were found to be significantly thinner in Groups II and III when compared with Groups I (p < 0.05).ConclusionsThe results of this study suggested that topical or oral administration of NS oil supressed the inflammation and fibroblastic activity in the lamina propria of the myringotomized TMs of the Guinea pigs. For providing further evidence to use plant extracts as antioxidant and antiinflammatory therapy after myringotomy or ventilation tube insertion, further clinical studies with larger population will be essential.     

Otological findings in idiopathic hyperphosphatasia.

A 17-year-old male patient was admitted because of progressive hearing loss since the age of six. His former blood and radiology investigation had revealed idiopathic hyperphosphatasia. On ENT examination bilateral thickened tympanic membranes with severe mixed-type hearing loss was diagnosed. Computerized tomography (CT) demonstrated expansion of the calvarial bones, including the temporal bones, except for the otic capsule. Middle-ear exploration revealed thickened middle-ear mucosa and a stone hard, immobile bony mass instead of the normal ossicular chain at the posterior superior part of the mesotympanum. No ossicular reconstruction could be attempted and the patient was rehabilitated with a hearing aid.     

Experimentally induced rhinosinusitis in rabbits

OBJECTIVE: The purpose of this study was to develop an experimental rhinosinusitis model by using bacteria-added absorbable material for temporary ostial obstruction. METHOD: Absorbable gelatin sponge was inserted between the endoturbinals and the ostium of the sinus. In the first group, the effects of surgical procedure and Gelfoam on ostial mucosa were examined macroscopically. In the second group Gelfoam was moistened with Staphylococcus aureus (ATCC 25923). The sinuses of rabbits were examined by coronal com puted tomography before each surgical procedure and sacrifice. The animals were sacrificed at the first, second, fourth eighth, and tenth weeks. Histologic and microbiologic examinations were performed. RESULTS: In the first group, fibrotic bands and adhesions were observed between the ostium of the maxillary sinus and the endoturbinals in the first and second week. In the second group, a thick purulent discharge that invariably filled the sinuses of the inoculated side was seen after the first week of induction, and opacity, which was determined radiologically, did not disappear until the end of the study. CONCLUSION: In this study, an experimental rhinosinusitis model was accomplished. It is currently believed that obstruction of the ostium with mucosal edema, polyps, or tumour leads to maxillary sinusitis. In this model, the pathogenesis of human sinusitis was imitated by temporary occlusion of the ostium with bacteria-added Gelfoam. This model can be used in further studies to explore the role of the ostium in the pathogenesis of sinusitis.