The Eustachian tube is the only ventilation rout of the middle ear and mastoid. The Eustachian tube is a potential tube opened by muscle action mainly the tensor veli palatine and it has a mucosal lining. Eustachian tube divided into two portions bony and cartilaginous. Eustachian tube regulates the middle ear pressure. The Eustachian tube dysfunction is found to be the main cause in development middle ear pathologies as glue ear, sclerotic changes, and even Cholesteatoma [1]. Ear with poor Eustachian function, has abnormal pressure equalization [2]. The function of Eustachian tube can predict success of myringoplasty [3]. Temporalis fascia graft is found to be weak so prone to retraction and perforation due to change of middle ear pressure. As the cartilage is rigid and stiff, it tends to resist resorption and retraction due to middle ear pressure changes [4]. The cartilage has a very low metabolic rate that enables it to withstand long periods in ischemic situations. It can be harvested easily from the operative field in adequate amount [5]. Over the past twenty years autologous cartilage grafts have been used to prevent retraction pockets and cholesteatomas in patients with Eustachian dysfunction. Cartilage grafts can be used alone or in combination with fascia grafts. Hearing results after cartilage tympanoplasty have been shown to be comparable to temporalis fascia and perichondrium [6,7]. In review of literature there were no researches mentioned the thickness of the cartilage grafts in cases of eustachian dysfunction. The aim of this study is to optimize and evaluate the effectiveness of using partial cartilage graft in three thicknesses for reconstruction of tympanic membrane perforation in cases with poor Eustachian tube function.

Informed consent was obtained from all patients included in our study. The approval was obtained from our institutional Research Ethics Committee. All included patients were assessed by history and clinical examination otoendoscopy and hearing assessment by pure tone audiometry. Myringoplasty was done for 90 consecutive patients with central tympanic membrane perforation. Inclusion criteria included patients aged 18-50 years, dry large and subtotal perforations with no otorrhea for at least 3 months, tubotympanic type, no ossicular pathology, and no history of ear operations. We excluded cases with normal functioning Eustachian tubes, small, medium and total perforations; patients aged ? 50 years, diabetes mellitus and non-fit for surgery. History and Otoscopic examination were achieved in all cases. Audological evaluation was carried out using a clinical audiometer (Madsen, Model OB 822). Pure tone audiometry at frequencies 250 to 8000 Hz) and Eustachian tube function were carried out prior to operation. Eustachian tube function was done using a Madsen immittance-meter as follow: negative pressure of -200 mm H₂O was established in the external canal and middle ear, then the patient was asked to swallow and the residual pressure was measured. Eustachian tube function was classified into: a) Good: when the residual pressure was reduced to >-100mm H₂0. b) Fair: when patient can reduce the -200 to a residual pressure between -100 and -200 H₂O. c) Poor: when the residual pressure was not reduced below -200mm H₂O with swallow [8]. Patients were divided into 2 main groups A and B. group. Group A (60 cases) was patients with large perforations and Group B (30 cases) with subtotal perforations. Each main group was divided into three graft groups (Gr1, 2 and 3) of equal number of patients according to types of graft used in repair. Gr1 grafted by full thick cartilage, Gr2 grafted by 0.5mm cartilage and Gr3 grafted by 0.3mm cartilage. Tympanometry was type A in all cases grafted by Gr2 and Gr3. In Gr1 tympanometry was type A in 10 cases, type B in 5 cases and type C in 15 cases. Graphpad. Quickcalcs software. P value and statistical significance were measured by the unpaired t test

Local anaesthesia with sedation was used in most cases (30 males and 40 females). General anesthesia was done in uncooperative cases (5 males and 11 females). Through a post auricular approach, a laterally based vascular strip in the postero-superior wall of external auditory canal was taken by making two vertical incisions (6^th o’clock to 1^st o’clock in right ear and to 11^th o’clock in left ear) , connecting by one horizontal incision 3mm from the annulus. The vascular strip is elevated and laterally retracted away from the field. The margin of the perforation is trimmed by sickle or needle. The annulus is elevated to enter the middle ear. The cartilage graft was harvested from the back of concha by the same posterior incision. An oval piece of cartilage is excised with perichondrium on one side in a form of tail to be laid on posterior metal wall for vascular supply. The edge of cartilage was trimmed 2 mm circumferentially to become a discoid of ≤ 10 mm. A notch was done in the cartilage to fit the manubrium of the malleus. In this study, we used cartilage grafts of three thicknesses (full thickness, 0.5mm and 0.3 mm). Thinning of the cartilage was done by a Concho tome (Kurz Co. Germany). The graft is placed by underlay technique, with the cartilage facing the middle ear cavity. The malleus is fitted into the notch in the cartilage. Pieces of gel foam are placed in the middle ear cavity to support the graft. The vascular flap is draped on the perichondrium tail and all onto the bony wall. Gel foam is packed in the canal then antibiotic ointment gauze pack. The pack is removed after ten days and gel foam remnants after three weeks.

This study was conducted on 90 patients with dry large and subtotal tympanic perforations. They were 50 males and 40 females. The mean age at operation was 25.4 years with a range from 18 to 50 years (standard deviation ± 11.7). The mean of follow up period was 18 months. The take rate was 100% in group A Gr1, group A Gr2, group B Gr1 and group B Gr2. Take rate was 90% in group A Gr3 and 70% in group A Gr3 and GB3 respectively (Tables 1 and 2).

Table 1: Take rate, pre and postoperative pure tune average mean and p value in group A.

Table 2: Take rate, pre and postoperative pure tune average mean and p value in group B.

Table 3: Post-operative PTA Confidence interval and P value in group A1, 2 and 3.

Table 4: Postoperative confidence interval and P value in group B1,2 and3.

Table 5: Tympanometry types in different graft groups.

The hearing average was significantly improved postoperatively in all groups. The hearing average was markedly improved in patients of group A and B grafted by 0.5mm (Gr2) and 0.3mm thicknesses (Gr3) also hearing was extremely improved with the use of 0.3mm cartilage in group A and B (Tables 3 and 4). Tympanometry was type A in Gr2 and Gr3 in both groups A and B, but tympanometry was type B in Gr1 in both groups so the thinner graft the increased type A tympanometry (Table 5).

The main aim for tympanic membrane reconstruction should be the take of the graft for intact new tympanic membrane provided that the new drum has acoustic characteristics more or less similar to the original drum as well as stable enough to resist pressure changes in the middle ear. Many graft materials is used for repair of the tympanic membrane perforation, however the temporalis fascia remains commonly used for myringoplasty. The negative middle ear pressure due to poor function of Eustachian tube leads to retraction and perforation of the temporalis fascia grafts. Belal [9] stated that Eustachian tube dysfunction is one important non-technical cause of myringoplasty failure. Rigid grafts as cartilage may be highly useful to resist retraction and perforation [10]. In our study we used cartilage in different thicknesses as mentioned in method section. The perichondrium is preserved for viability of the graft. The exact thickness of the graft is done by using a conchotome. Zahnert [11] reported that cartilage with thickness less than 0.5mm had the same acoustic properties as the normal tympanic membrane and temporalis fascia. Regarding the take rate in our study was complete with full thickness and 0.5mm thick cartilage in large perforations and subtotal perforations. There was significant difference in hearing results between the full thickness graft and 0.3 mm and 0.5 mm groups with more improvement in lesser thickness grafts. The postoperative air bone gap had the least postoperative improvement in full thickness cartilage as compared to other thinner grafts. The difference in hearing improvement was statistically significant (P>0.0001) in Gr1 and Gr2 but was extremely significantly improved in Gr3. Tympanometry was type An in Gr2 and Gr3 of group A and B cases. Tympanometry was type B in Gr1 of groups A and B. So thinner cartilage grafts had better hearing prospects.

We conclude that Eustachian tube function should be assessed preoperatively in all cases planned to do myringoplasty. Cartilage grafts are without doughty better than the temporalis fascia in tympanic membrane reconstruction in cases with poor Eustachian tube function. The cartilage thickness should not exceed 0.5 mm and not to be more than 0.3 mm for tympanic reconstruction in order to get the best take rate together with better acoustic results.

No conflicts of interest to declare.

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