Laser Myringotomy Research Articles

Chronic tympanic membrane perforation: Histopathological evidence of the experimental model

ObjectivesThis study aims to compare the effectiveness of three different models of chronic tympanic membrane perforations. MaterialsThe experimental study included 18 male chinchillas, divided into 3 equal groups. Group 1 perforations were performed with infolding technique myringotomy. Laser myringotomy was performed for perforation creation in Group 2. Group 3 perforations were performed with infolding myringotomy combined with ventilation tube insertion. At the end of the follow-up period, which lasts 8 weeks, all tympanic membranes with patent perforations were examined histologically. ResultsAlthough, the mean perforation patency in Group 2 was significantly higher than in Group 1 (5 vs. 2.4 weeks, p < 0.01), both of them failed in creation of chronic perforation according to time parameters. Group 3 demonstrated the longest mean perforation patency among investigated models (8 weeks). In Group 3, histological examination of perforations, which were considered to be chronic, revealed, that stratified squamous epithelium continued from the lateral surface around the perforation edge to join with the medial mucosal layer of TM. ConclusionOur findings demonstrated that the combination of infolding technique and ventilation tube insertion seems to be a potential candidate for an effective animal model of tympanic membrane perforation. Further large-scale studies are required to verify our promising results.

A study to compare the outcomes of laser myringotomy and conventional incision myringotomy

&lt;p class="abstract"&gt;&lt;strong&gt;Background:&lt;/strong&gt; The objective of the study was to compare the outcomes of laser myringotomy and incision myringotomy in terms of operating time, patency of opening, hearing improvement, and disease recurrence.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; This study is a prospective study done among 35 children and 68 ears. All cases which were diagnosed to have otitis media with effusion were randomly assigned into two groups: group 1 was treated with diode laser myringotomy and group 2 was treated with conventional incision myringotomy without grommet insertion. These patients were followed up at regular intervals and compared in terms of operating time, patency of opening, recurrence of disease and hearing improvement. &lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results:&lt;/strong&gt; Diode laser myringotomy took an average operating time of 6.38 minutes and the patency of opening was maintained for an average of 13.59 days, compared to the average operating time for incision myringotomy of 9 minutes, and the patency of opening being 12.35 days. These differences were statistically significant (p&amp;lt;0.0001 for operating time and p=0.041 for patency of opening). Hearing improvement was also found to be better in laser myringotomy group (p=0.021). &lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; Diode laser myringotomy is an effective, easy and less time-consuming modality than incision myringotomy for the treatment of otitis media with effusion. &lt;/p&gt;

Advances of chronic tympanic membrane perforation animal model

Chronic tympanic membrane perforation in an animal model has been widely used. The ideal model is a lasting and stable perforation without infection. For half a century, several physical modalities have been evolved, such as thermal injury, infolding technique, tympanostomy tube, re-myringotomy, and laser myringotomy. Chemical methods using chemical substance inhibiting growth and repair of cells as well as using gene defect animals are also applied. We have found the success rate is lower when using only one method and it would be better to combine physical and chemical approaches. In this article, we review the research advances in the establishment of chronic tympanic membrane perforation animal model.

Improving the methods of diagnosis and treatment of otitis media with effusion

The study involved 172 patients with otitis media with effusion. All patients as a method of early diagnosis of otitis media with effusion conducted multislice computer tomography (MSCT). This made it possible to check the effectiveness of conservative treatment and timely perform surgical treatment, including sanitizing intervention on the middle ear with the erased clinical picture of acute mastoiditis, and to avoid complications. With the help of MSCT of the temporal bones with the dynamic observation of patients with high accuracy, you can confirm the full restoration of pneumatization of the middle ear cavities or identify possible recurrences of exudate accumulation. Patients who underwent surgery were randomly divided into 2 groups, depending on the duration of the laser myringotomy: on the 3rd day of hospital treatment (first group) or on the 7th day of hospital treatment (second group). Absence of otorrhea from the tympanic cavity and return of hearing in patients of the first group was significantly in a shorter period (p<0.05). CO2-laser myringotomy for patients with otitis media with effusion without positive dynamic by conservative therapy is most effectively in the early stages of the disease.

Bilateral Congenital Cholesteatoma.

To report the first large case series of extremely rare bilateral congenital cholesteatoma (CC). A retrospective cohort study. University hospital otology referral clinic. Six hundred four children with surgically confirmed CC. The bilateral CCs were compared with the unilateral CCs. The incidence of bilateral CC was 3.6% (22/615) per case or 1.8% (11/604) per child. Bilateral CC did not differ from unilateral CC regarding its demographics, and invasiveness by the proportion of advanced CC as 31.8% (7/22) versus 28.2% (167/594). But the invasiveness or location randomly differed between the ears, that advanced CC per child was higher as 45.4% (5/11). Bilateral exploration was attempted with a concern for hearing loss, which featured a combination of laser myringotomy to treat early CC and endaural laser-assisted single-stage inside-out cholesteatoma surgery to treat advanced CC. Bilateral exploration was difficult in three children with initially negative otoendoscopy. Among the seven advanced CC, proportion of anterior type was 71.4% (5/7), who all exhibited more than 20 dB HL, but two posterior type retained normal hearing. Therefore, bilateral advanced CCs of anterior origin showed poorest hearing outcome as bilateral more than 20 dB HL, which were in two children. Six second-look operations and one third-look operation were required to treat six residual CCs (30%) in four children (40%), including bilateral residual CC in two (20%); such reoperations were significantly more frequent than in unilateral CC. The diagnosis of bilateral CC required high index of suspicion from TBCT, and early bilateral exploration.

The application of the method of radiofrequency myringotomy under the experimental conditions and in the clinical practice

Exudative otitis media is a widespread pathological condition in the human population. In the recent years, the treatment with the electric current having the frequency up to 3.8 MHz has found the increasingly frequent application, in addition to shunting and laser myringotomy, for the perforation of the tympanic membrane to facilitate removal of exudate. The objective of the present study was to evaluate the effectiveness of the application of the electric current with the frequency up to 4 MHz for myringotomy in the patients presenting with exudative otitis media under the experimental conditions and in the clinical practice. The experimental studies were carried out with the use of the isolated temporal bones (ex vivo) and laboratory animals (in vivo). The clinical studies included the surgical treatment of 41 patients presenting with exudative otitis media using the electric current with the frequency of 4 MHz and laser irradiation with the subsequent evaluation of the inflammatory manifestations in the tympanic membrane tissues during the early post-operative period. It was shown that the method of myringotomy with the application of the electric current having the frequency of 4 MHz is safe and causes no complications. Moreover, it is accompanied by the development of the minimally active inflammatory processes in the tympanic membrane tissues during the early post-operative period.

Comparative analysis of the effectiveness of bypass surgery and laser myringotomy used to treat exudative otitis medium

The objective of the present study was the comparative analysis of the surgical method employed for the treatment of exudative otitis medium, such as bypass surgery and laser myringotomy. The study included 125 patients suffering from the said pathology. The following two methods were used in cases of poor efficiency of conservative therapy: laser myringotomy with the use of a LUMENISc CO2-laser operated at a wavelength of 10.6 mcm with the SurgiTouch scanner and bypass of the tympanic cavity. Each of these methods was applied to treat 38 patients. It was shown that discharge from the treated tympanic cavity stopped sooner after laser myringotomy than after surgical bypass. The recovery of hearing ability according to the results of tonal threshold audiometry also took less time after laser myringotomy than after surgical bypass. The same is true with respect to the restoration of the drainage function of the Eustachian tubes. The frequency of recurrent exudate formation (in percent) in the patients undergoing laser myringotomy was significantly lower than after surgical bypass.

Simulators and models for laryngeal laser surgery and laser myringotomy.

Simulators and models for laryngeal laser surgery and laser myringotomy.

Flexible Integration of Laser Myringotomy and Ventilation Tube for Bilateral Otitis Media with Effusion: Analysis of Laser Tympanostomy versus Ventilation Tube

BackgroundThe aim of this study was to evaluate the efficacy of laser myringotomy (LM) compared to ventilation tube (VT), and to assess the clinical success criteria of LM-assisted VT insertion as the flexible alternatives avoiding GA for the treatment of bilateral consistent otitis media with effusion (OME).Methods and FindingsLM under topical anesthesia was followed by VT insertion in cooperative children using Acuspot® 712 CO2 laser micromanipulator attached microscope. Sixty children failed VT and bilateral laser tympanostomy was done (group LL), and 130 children tolerated VT on one side but LM on the other side (group LV). The efficacy of LM was compared to VT regarding recurrent effusion and reoperation as the outcome measure; firstly, by ear-to-ear matched pair analysis in LV, and secondly between LL vs. LV. Long-term outcome was compared to control group who received both VT under GA (group GAVT) regarding the outcome of additional VT and GA.ResultsThe effectiveness of LM per ear was equivocal as 46.9% and 40.8% in LV and LL respectively; but the effectiveness per children was further lower in LL as 28.3%, which was a limitation of LM for bilateral OME. LL required reoperation in 71.7% mostly requiring impending GA in 51.7% within 4.7 months, thus was a controversial treatment. But LV required GA in 20.8% during the 27.2 months long-term follow-up, which was second set of VT and adenoidectomy that were also comparably required in GAVT control with multiple GA.ConclusionStandard GAVT was more recommended for bilateral OME than bilateral LM (LL) in our practice. But LM was selectively effective for some children, that combined approach with LM plus VT provided comparable period to outgrow OME as effectively as GAVT, when LM was supplemented with one VT side with recovered hearing.

Diode laser myringotomy for short-term middle-ear ventilation: a pilot study on children

EnAbstract Objective The aim of the study was to evaluate diode laser myringotomy (DLM) in children for the management of Eustachian tube and middle-ear disorders that require myringotomy for short-term treatment. Study design This is a prospective clinical study. Patients and methods The study comprised 20 children selected to undergo DLM for middle-ear ventilation as a mode of treatment for recurrent acute serous otitis media; these children suffered from persistent middle-ear effusion and had experienced failure of medical treatment for at least 8 weeks. Postoperative weekly visits to evaluate the myringotomy opening (MO) were carried out until healing was recorded. The Eustachian tube and hearing ability were evaluated preoperatively and postoperatively 4 weeks after healing of the tympanic membrane. Cases were deemed to be failed when the MO closed early within the second week postoperatively without improvement in hearing, or the myringotomy persisted until the end of the third month postoperatively. Outcome measures were the state of the MO and of the ear drum, the patency time of the myringotomy, improvement in hearing and Eustachian tube function and incidence of operative and postoperative complications. Results The mean operative time was 5 min. No operative complications occurred. Procedural success was achieved in 16/20 ears (80%). Two ears showed postoperative persistent perforations, and two recorded early closure of the MO. The mean improvement in the air/bone gap was 12 dB for the successful cases. Twelve ears with healed MOs showed type A curve (75%). Four ears showed type C curve (25%) and needed further management. Conclusion DLM is useful in children for the management of Eustachian tube and middle-ear disorders needing myringotomy for short-term treatment.

Laser-assisted myringotomy versus conventional myringotomy with ventilation tube insertion in treatment of otitis media with effusion: Long-term follow-up

Otitis media with effusion is the most common cause of conductive hearing loss in the pediatric population. Insertion of ventilation tubes with or without adenoidectomy is the accepted and standard surgical procedure. CO2 laser myringotomy without tube placement has been advocated as an alternative treatment. To compare long-term follow-up results of laser versus classical myringotomy with ventilation tube insertion over five years. 86 patients with bilateral otitis media with effusion were divided into two groups: laser myringotomy group and myringotomy with ventilation tube insertion group, with follow-up in hearing results and recurrence rates over five years. The mean patency time of myringotomy in laser group was 23 days, while the mean patency time of the ventilation tubes ears was 4.0 months in myringotomy group. Twelve patients in laser group (13.9%) showed a recurrent otitis media with effusion compared to 9 patients in myringotomy group (10.4%). Laser fenestration is a less effective alternative to myringotomy and tube placement. The recurrence rates after both procedures did not show statistical significance over long follow-up. It might be considered as an effective alternative to classical surgery and ideal for short-term ventilation.

New therapeutic strategy for treating otitis media with effusion in postirradiated nasopharyngeal carcinoma patients

BackgroundPostirradiation otitis media with effusion (OME) is the most common radiotherapy-associated otologic complication associated with nasopharyngeal carcinoma (NPC). This study's aim was to evaluate the efficacy of laser myringotomy followed by intratympanic steroid injection (LMIS) for treating OME in postirradiated NPC patients. MethodsFrom August 2002 to January 2006, 27 newly diagnosed NPC patients who developed OME after a full course of radiotherapy were enrolled. Laser myringotomy was performed followed by once-weekly administration of steroids (0.5mL dexamethasone at a concentration of 5.0mg/mL) into the middle ear for 3 consecutive weeks. The success rate of dry eardrum perforation and the prognostic factors associated with OME resolution were analyzed. ResultsThe procedure was performed on 44 ears of 27 patients. The mean follow-up period was 37 weeks. Of the 44 ears, 23 (52.3%) developed persistent eardrum perforation, 18 (40.9%) developed recurrent OME, and three (6.8%) were disease-free on follow-up. Of the 23 ears with persistent eardrum perforation, 18 (78.3%) were diagnosed as dry perforation. The absence of pretreatment mastoiditis was an independent factor associated with OME resolution (p<0.001). ConclusionLMIS is a quick, minimally invasive, office-based technique that can be repeatedly performed to treat highly recurrent postirradiation OME, and it results in relatively slight pain to NPC patients. Long-lasting dry eardrum perforation allows for adequate middle ear ventilation and drainage and guarantees sustained relief from symptoms. The absence of preoperative mastoiditis is a favorable prognostic factor associated with OME resolution.

半导体激光鼓膜造孔术的光学系统设计

An optical system to perform the semiconductor laser myringotomy with the help of a video display and a pilot laser was designed and manufactured.First,the 650 nm laser output from a single emitter and the 810 nm laser emitted from a laser diode array were coupled into a fiber with a core diameter of 200 μm and a numerical aperture of 0.22 by using beam shaping and wavelength beam combination technologies.Then,an achromatic lens was used to collimate the dual wavelength laser output from the optical fiber and the other achromatic lens which could move along principal axis and consequently change the spot size was used to focus the dual wavelength laser to the eardrum.Meanwhile,laser and imaging lights were coupled as coaxial by using a hot mirror and the imaging components from markets.Moreover,the location of myringotomy could be piloted by red light on a computer monitor.According to the results of measurement,the laser power output from the system can be continuously adjusted from 0 to 13.3 W,and the spot size can also be adjusted between 1-3 mm.The system can decrease the operation time and the possibility of surgery side effect;moreover,the myringotomy for children needs not any anasthesia.In addition,the system has the virtues of low volume,light weighted and high wall-plug efficiencies compared with other candidates.

Differences between children and adults with otitis media with effusion treated with CO 2 laser myringotomy

Background The safety and advantages of CO 2 laser myringotomy for otitis media with effusion (OME) are well described. The goal of such treatment is to avoid unnecessary ventilation tube insertion. Comparisons between different age groups treated with this modality are lacking, and prognostic factors for treatment outcomes are not available. Methods We conducted a retrospective cohort study that included 130 children (160 ears) and 96 adults (108 ears) with OME persisting after conservative antibiotic treatment. In eligible patients, we performed laser myringotomy in the affected ear. Follow-up was scheduled every week for 1 month and then every month for 6 months. Results for 233 ears were available for analysis; 24 ears were excluded (19 due to cancer, four due to a cleft palate, and one due to Down syndrome) and 10 patients (11 ears) were lost during follow-up. A logistic regression model was used for analysis, with success of therapy as the binary outcome. Results Adult patients had more unilateral lesions ( p < 0.001) and serous fluid effusions ( p < 0.001) than did the pediatric patients. However, there was no significant difference in the cure rate (children: 58.1%; adults: 64.7%) and positive culture rate (children: 15.1%; adults: 14.3%) between patient groups. Three factors were found to be associated with a poor prognosis: multiple occurrences in children ( p < 0.001), mucoid effusion ( p = 0.04), and a history of ventilation tube use in adults ( p < 0.001). No other variables predicted treatment outcome. Conclusion Our findings suggest that CO 2 laser myringotomy is a useful treatment modality for OME in children and adults, except for children with multiple occurrences and in adults with mucoid effusions and a history of ventilation tube use.

Re-evaluation of CO 2 laser myringotomy for managing children with persistent acute otitis media

Background This study aimed to re-evaluate the utility of CO 2 laser myringotomy in children with persistent acute otitis media (PAOM). Methods From September 2002 to April 2008, 40 children with PAOM received CO 2 laser myringotomy. PAOM was defined as continuing symptoms and signs after systemic antibiotic treatment. Before laser myringotomy, the eardrums were checked under videotelescopy, pure tone audiometry or behavior audiometry and tympanometry. Middle ear effusions were collected using our own designed bottle culture device after laser myringotomy. The patients were followed up at outpatient clinics for 3 months. Cultured middle ear pathogens, healing time of the eardrums, hospital course (for admitted patients), and the development of middle ear effusions were recorded. Results Forty children with 53 ears with PAOM were enrolled. Eight patients (20%) had bilateral disease and underwent bilateral laser myringotomy. The overall culture rate was 28.3%, and Streptococcus pneumoniae was the most common pathogen. Eight patients (20%) were admitted for intravenous antibiotics. The average eardrum healing time was 22 days in those with positive cultures, and 16.4 days in those with negative cultures ( p = 0.125). All eardrums healed in 1 month. The resolution rate was 62.5% at 1 month. Patients with bilateral PAOM were prone to have positive middle ear culture (5/8) compared with those with unilateral PAOM (8/32) ( p = 0.086). Conclusion CO 2 laser myringotomy is an applicable means of treating PAOM. S pneumoniae is the most common pathogen in PAOM. CO 2 laser myringotomy allows for the drainage and culture sampling of middle ear effusion, relieving the need of taking prolonged medication.

Resolved effusion on myringotomy: A study of dry tap without general anesthesia

Objectives Finding a resolution of middle ear effusion using myringotomy, or dry tap (DT), is relatively common, but its clinical outcome is confounded by general anesthesia (GA). The confounding effect of GA and a time delay can be removed because laser myringotomy can be completed under topical anesthesia, which is a routine procedure for otitis media with effusion (OME) before GA in our clinic. DT without GA would clarify the clinical outcome, and the percentage of recurrence for OME after DT would be clinically relevant. The objectives of the present study are (1) to clarify the clinical nature of DT without including the confounding effect of GA and a time delay and (2) to determine if OME recurs when a ventilation tube (VT) is not used for DT. Methods The control group consisted of 308 children who received an unilateral myringotomy due to a natural resolution in the contralateral ear. The experimental group consisted of 296 children who had a bilateral myringotomy, and a ventilation tube was not inserted for DTs after laser myringotomy under topical anesthesia. The rate of DT and the recurrence rate of OME without tube insertion was the main outcome measure. Results In the control group, which showed a natural resolution, the rate of DT was 16.9% (52/308) of patients, and DT was more common in non-B tympanometry, which only had a recurrence rate of 17.3% (9/52). In the study group, 3.7% of patients showed unilateral DT (UDT) with contralateral positive effusion, and 5.4% of patients showed bilateral DTs (BDTs). BDT showed a non-B tympanometry pattern and a low rate of recurrence (25.0%), which was similar to the control group. UDT showed a B-type tympanometry in 81.8% of the patients, and the recurrence rate was significantly higher (68.2%; 15/22) than the BDT and control patients. BDT or DT with signs of natural resolution showed a low rate of OME recurrence regardless of tympanometry, and thus, patients do not need a VT. Conclusions DT was not rare even without GA and the associated time delay, and DT was more common in the children that showed a natural resolution. However, microscopy and tympanometry was imperfect to predict dry tap, and thus, the surgeon needs to be prepared for individualized management of DT. UDT with B-type tympanometry and contralateral persistent effusion frequently recurred without tubes, and thus, VT for UDT appeared to be necessary.

Acute tympanic membrane perforations and the early immunological response in rats

Conclusions: This study showed that macrophages, B cells, and T cells occurred at different frequencies, localizations, and times after acute laser tympanic membrane perforation. Immunological cells were most prevalent in the proliferative mass adjacent to the annulus region. The cellular immunological response in freshly perforated eardrums was unexpectedly aggressive. Objectives: To study the occurrence of immunocompetent cells during the healing process of fresh perforated tympanic membranes. The information could be used to develop alternative outpatient procedures in the cure of chronic perforations, replacing conventional surgery. Materials and methods: A laser myringotomy was carried out in Sprague-Dawley rats, which were sacrificed at 3 and 6 days after the myringotomy. Tympanic membrane sections were stained immunohistochemically according to the avidin-biotin method, targeting macrophages, B cells, and T cells. Semi-quantification was performed; positive cells were counted and mean values were calculated. Results: Macrophages and B cells were most frequent at day 6 and T cells at day 3 after laser myringotomy. B cells were the most prevalent studied cell type. T cells peaked at day 3, after which they decreased in number. Most immunocompetent cells were observed in the proliferative mass at the edge of the perforation.

Die Gefährdung des runden Fensters bei der CO2-Laser-Parazentese

In CO2 laser myringotomy, a self-healing perforation is typically created in the lower anterior quadrant. A prominent anterior meatal wall may cover that quadrant and necessitate dorsal perforation of the eardrum. This study orientationally assessed the risk of damaging the round window membrane (RWM) when applying the laser in dorsal eardrum areas.The round window was exposed by otomicrosurgery in 61 human petrous bone specimens. CO2 laser myringotomy was previously performed with twice the standard power (25 W, 180 ms, 2.2 mm) in the lower posterior quadrants of 25 specimens, the beam being applied directly to the round window niche in five specimens, and the effect of the laser radiation was documented. The RWM was subsequently exposed in all petrous bones, and the angle correlation of the membrane to the direction of the laser beam was digitally measured.The laser did not damage the membrane of the round window in any of the cases. The angle between the RWM and the external auditory meatus was below 30 degrees in 97% of the petrous bones and thus had a nearly parallel course.Localization of the window caudodorsal to the meatal wall, bone overhanging the membrane, mucosal duplications, and membrane alignment nearly parallel to the laser beam make it virtually impossible to reach this membranous structure with the CO2 laser.

Skuteczność tympanopunkcji w leczeniu dzieci chorych na wysiękowe zapalenie ucha środkowego

Otitis media with effusion is the most frequent cause of conductive hearing impairement (HL) at pediatric age. This entity can be asymptomatic for an important period of time (silent OME). There is a surgical and a nonsurgical approach for OME. In case of failure of conservative treatment of OME the ventilation tube insertion (VT) with adenoidectomy alone or combined with tonsillectomy should be choosed. If the hearing loss is less than 20 dB children are candidates for conservative treatment and myringotomy. From 1999 to 2003, 50 children with bilateral and 9 with unilateral OME underwent the surgical treatment in our ENT Department. Mean age of patient population was 6,8 years. Clinical evaluation of the OME treatment outcome was done in 2004. Surgical procedure involved myringotomy, aspiration of the middle ear effusion, middle ear irrigation with soline solution 0.9 % Sodium Chloride (NaCl) followed by suction of diluted glue. Depo-Medrol (methylprednisolone acetate) was administrated into the middle ear. Our procedure included the management of the upper airways obstruction. Good long-term outcomes after surgical treatment of OME were obtained in 30 patients (79%). In this group of children the upper airways management included adenoidectomy and partial tonsillectomy. 8 children presented poor response to the treatment. In this group the surgical procedure consisted of adenoidectomy and inferior turbinate reduction. Two children presented acute otitis media and improved after conservative treatment. Other children with poor outcome were: a boy who underwent multiple surgical procedures due to laryngotracheal stenosis, a girl who suffered from chondrodysplasia. Remaining two patients presented few months ago aggravation of conductive hearing loss. According to positive familial history they underwent allergical examinations. One boy was planned for readenoidectomy and laser myringotomy, a girl already operated at the age of tree years, was planned for ventilation tubes insertion and readenoidectomy in another ENT Department.

Healing time, long-term result and effects of stem cell treatment in acute tympanic membrane perforation

The incidence of otitis media in children between the age of 2 and 6 years is well documented. Repeated attacks may cause acute and chronic perforations. The surgical treatment for repairing chronic perforation is quite uncomfortable for the patients of this age group because of the invasiveness of this treatment. The aim of this study was to determine the long-term influence of embryonic stem cells on acute perforations and the effect of gelatin as a vehicle for applied stem cells. The possibility of teratogenic effects of the stem cells was also observed. Bilateral laser myringotomy was performed in 17 adult Sprague-Dawley rats, divided into two groups. Gelatin, a substance suitable as vehicle for bioactive material was used bilaterally around the perforation in group A, to serve as a scaffold for repairing tissue. The stem cells were used in the right tympanic membrane perforation leaving the left tympanic membrane as a control. The animals in group B received the same treatment except for the use of gelatin and in addition received an immuno-suppressive agent. After half a year of observation the mechanical stiffness of the tympanic membrane was measured by moiré interferometry for group B and the morphological study was performed by light microscopy for both groups A and B and electron microscopy for group A. Stem cell treated ears did not show any enhanced healing of the perforation although a marked thickening of the lamina propria was observed compared with control group. After half a year the strength and the stiffness of the tympanic membrane was almost the same for both treated and untreated ears. No evidence of teratoma was found after half a year. This study suggests that the stem cells stimulate the proliferation of connective tissue and fibers in the lamina propria, possibly mediated by secreted substances, although the stiffness properties do not seem to be altered. The use of gelatin does not seem to enhance the healing process of the tympanic membrane perforation.