INTRODUCTION
The two classical repair methods of the tympanic membrane (TM) perforation are either underlay or overlay method. In underlay myringoplasty, the graft is located entirely medial to the remaining parts of the TM and the malleus. While for overlay technique, the graft is inserted lateral to the annulus and the residual middle fibrous layer of the TM after elevation of the TM squamous layer.[1]
The success rate following myringoplasty has a broad range. The postmyringoplasty success was recorded down to 88%[1] or 60% in adults and reach 35% in children.[2]
Anterior and subtotal perforations represent constant causes of suboptimal myringoplasty results[3,4] because anterior TM part has an unfavorable rate of closure and less hearing improvement[4,5] due to less vascular supply[6] and more metabolic demand at the anterior annulus.[7] So anteriorly, the vascular strip must not be disrupted during ear surgery.[6] Moreover, there is no structure to provide graft support at the anterior TM margin. Thus, the TM remnant was previously utilized as a medial or lateral support but is frequently inadequate, particularly in the subtotal perforations. Additionally, anterior canal blunting and graft lateralization can happen with onlay or lateral techniques. Access and visualization to all the perforation and annular rims is considered another challenge added to the practical difficulties during repairing anterior and subtotal TM perforations.[8]
Therefore, anterior and subtotal TM perforation remains a challenge for otosurgeons, and there is still a demand to investigate methods to enhance the TM healing after tympanoplasty in the challenging subtotal TM perforation, particularly in its anterior segment.[2,3]
This type of TM perforation has been repaired by a variety of operative procedures, such as the usage of sandwich graft tympanoplasty and over-under tympanoplasty, but still, best method is not found.[9]
Even though temporalis fascia is one of the most widely used grafts,[1] there has been no report showing the success rate of tympanoplasty for only large defect of TM using fascia.
The aim of the present work was to describe and assess the modified double-layer medial graft (underlay grafts) in myringoplasty using temporalis fascia for subtotal TM perforation in comparison to the results of the classic single-layer underlay graft in myringoplasty using temporalis fascia for the challenging subtotal TM.
PATIENTS AND METHODS
The present work included 60 patients who had chronic tubotympanic suppurative otitis media (CSOM) with very large TM (subtotal) perforation without ossicular affection for whom myringoplasty was done from October 2015 to December 2019 at tertiary university hospitals.
Preoperatively, the TM was divided into four quadrants following Saliba.[10] we graded central TM perforations into four grades: Grade 1 (small) perforation involves one quadrant or less of TM, Grade 2 (medium) perforation involves more than one quadrant and <2 quadrants of the TM, Grade 3 (large) perforation involves more than 2 quadrants and <3 quadrants of the TM, and Grade 4 (subtotal) perforation involves more than 3 quadrants of the TM and not total.
All included patients in this study had dry central Grade 4 (subtotal) TM perforation with seemingly healthy middle ear mucosa for at least 2 months preoperatively. Patients presented with cholesteatoma, active ear discharge, patients with suspected ossicular discontinuity (air-bone gap [ABG] >40 dB), patients with ossicular discontinuity during the operation, patients who operated by mastoidectomy, and patients who did not complete follow-up were excluded.
This study was accepted by the institutional review board and informed in print consent was signed by all patients. All patients were exposed to complete history taking, otoscopic, endoscopic, and microscopic examination, as well as preoperative pure-tone audiometry and laboratory testing. Underlay Type I myringoplasty with temporalis fascia graft was performed for all cases.
All the cases had been done by the same surgeon, and all the patients were evaluated with otoendoscopy and pure-tone audiometry preoperatively and 3 months postoperatively.
Patients were categorized into two groups randomly arranged as the first case in the one group and next in the second group and so on: the first (case) group comprised 30 patients for whom myringoplasty was done with double graft technique and the second (control) group included 30 patients for whom myringoplasty with one graft was done.
In both the groups, the graft was temporalis fascia and the technique used was underlay method.
Underlay myringoplasty was performed under general anesthesia with orotracheal intubation in all patients. Postauricular approach was utilized and the temporalis fascia graft was harvested for all cases. Perforation edges were freshened with trimming of the undersurface of the anterior rim, and then, the posterior tympanomeatal flap was elevated. The middle ear was explored, and the free ossicular mobility was insured.
We did not need to remove the epithelial layer of the anterior portion of the TM obviating the hazard of housing the skin and the epithelium below the graft.
The double-layer technique [Figure 1]
;)
Figure 1: The double-layer technique. (a) Large Grade 4 (subtotal) tympanic membrane perforation, (b) The first (large) graft is applied medial to the handle of malleus, (c) The second (small) graft is inserted between the large graft (first) medially and the remnants of the tympanic membrane laterally, (d) The arrangement from lateral to medial is tympanic membrane remnants, the second (small) graft, the first (large) graft
A large temporalis fascia graft was harvested. The graft was divided into two parts: a large part which was about one and half time size of the TM peroration and a small part which was about half size of the TM.
The large graft was first applied with underlay technique medial to the handle of malleus and supported medially with gelfoam pieces in the middle ear and the tympanomeatal flap was returned to its normal site and adjustment of the large graft medial to the TM remnants.
In the second (control) group, we used only this large graft and applied the gelfoam in the external auditory canal (EAC).
In the first group (case group), the tympanomeatal flap was elevated again carefully while keeping the large graft in its position, and then, the second harvested smaller graft was inserted anteriorly between the large graft medially and the anterior remnants of the TM laterally. The tympanomeatal flap was repositioned again to its normal position.
Thus, the anterior half of the TM perforation had a double-layer temporalis fascia graft in underlay technique. The gelfoam was applied in the EAC over the graft after repositioning of the tympanomeatal flap.
The postauricular incision was repaired in two layers, and the outer EAC pack was inserted followed by mastoid dressing application that was applied over the operated ear for a week.
Patients were discharged from the hospital at the day of surgery. Systemic broad-spectrum antibiotic was given for 1 week.
Postoperatively, all patients were assessed for complications, graft taking, and hearing gain. Success as regards closure of the TM perforation was named as an intact TM at 6 months after surgery. Success as regards hearing gain was named when there is 10 dB or more improvement at 6 months postoperatively.[11,12]
Evaluation of hearing was done by pre- and postoperative measuring of the average air and bone conduction thresholds recorded at frequencies of 250, 500, 1000, and 2000 Hz. Hearing improvement was measured by subtracting the average ABG preoperative and postoperative. Audiometric studies were reported following the guidelines of the Committee on Hearing and Equilibrium of the American Academy of Otolaryngology-Head and Neck Surgery.
Statistical analysis
Statistics were done via SPSS statistical software package (version 25; SPSS, Inc., Chicago, IL, USA). The significant P value was set <0.05.
Ethical clearance
Ethical approval of this study (Ethical committee ZU-IRB #10193/6-12-2022) was approved by the ethical committee of Zagazig University, faculty of medicine in 6-12-2022.
RESULTS
This study included 60 patients who had Grade 4 (subtotal) TM perforation caused by mucosal type of CSOM. They were randomly categorized into two equal groups (30 patients for each); the study (case) group included 30 patients, from which 11 (36.7%) males and 19 (63.3%) females with age range from 12 to 41 years (mean: 27.9 ± 8.5) years [Table 1]. The control group also included 30 patients, from which 9 males (30%) and 21 females (70%) with age range from 12 to 41 years (mean: 23.9 ± 11.1) years [Table 1].
Table 1: The results 6 months postoperative
Microscopic examination showed subtotal perforation (>3 quadrants of the TM) in all patients. Temporalis fascia tympanoplasty Type I was performed for all patients.
The follow-up period ranged from 6 to 14 months, and at 6 months postoperatively, all the patients are evaluated by otoendoscopy and pure-tone audiometry.
The success rate (graft taking) with no detected residual perforation was found in all cases of the study group (100% success rate in the case group) while 4 cases in the control group showed residual perforation (87.7% success rate in the control group) that is significantly better (P = 0.038, X2 = 4.286) than the success attained in the control group (21 patients, 70%) [Table 1].
The hearing gain success (>10 dB) was gained in 29 patients (96.7%) in the case group while it was accomplished in 21 patients (70%) in the control group that is significantly better (P = 0.00558, X2 = 7.68) than the success reached in the control group (21 patients, 70%) [Table 1].
No graft lateralization or displacement into the middle ear or retraction pocket was detected throughout the follow-up. No cases of anterior blunting, epithelial pearl, TM retractions, Sensorineural Hearing Loss (SNHL), tympanosclerosis, thin atrophic TM areas, or myringitis were seen.
DISCUSSION
The aim of myringoplasty is to reconstruct the TM and the mechanism for the sound conduction. To date, temporalis fascia is still the most frequently used graft for the TM reconstruction with 93%–97% success rate.[2]
It is frequently documented that repair of anterior or large subtotal perforation is less successful than that of central small perforations because of more technical difficulty[13] as well as less vascular supply[6] and more metabolic demand of the anterior annulus.[7]
Surgical closure of the anteriorly located TM perforation is challengeable either due to lack of graft support in underlay technique or anterior blunting in onlay techniques.[13,14] As well as proper access and visualization of the anterior meatal recess and the anterior annulus is another important challenge in anterior TM perforation.[3]
Single-layer graft tympanoplasty in large and subtotal TM perforation has lasting challenges such as graft lateralization, graft medialization, recurrent perforations,[15] and edge trimming with graft insertion under anterior remaining edge.[16]
In this study, we overcome this problem by using double-layer underlay temporalis fascial grafts in myringoplasty for subtotal perforation. The second temporalis fascia graft is smaller an inserted under the rim of the perforation anteriorly and lateral to the large first graft in order to support the graft anteriorly.
It is a simple technique with no risk of lateralization. Moreover, we do not have to make a tunnel that is considered technically difficult to some extent and without more extensive undermining of the anterior annulus. The second graft is small to be easily elevated by surface tension of trimmed undersurface of the anterior rim of TM perforation.
The underlay myringoplasty is mostly favored over the overlay myringoplasty because of the possibility of blunting, greater operative time, and difficulty needed with the overlay technique.[14] The chief disadvantages of the overlay method comprise the risk of anterior blunting and graft lateralization. If epithelial remnants are left behind, formation of a squamous cyst could occur.[3,17] An anterior tunnel under the annulus was used for graft stabilization.[6,7,14] In our study, we improve graft stabilization by using a double anterior fascial graft without creation of anterior tunnel or large anterior flap.
In this study, the graft taking is achieved in all cases which used the double-layer temporalis fascial graft with a success rate of 100% as well as 96.7% hearing gain success (>10 dB) in comparison to 86.7% success rate in graft take and 70% hearing gain success with the usage of single-layer temporalis fascial graft.
Ralli etal.[18] utilized the underlay anchored methods using the posterior and anterior tunnels to attain correct tension of the TM in addition to lateral traction of the handle of malleus. It led to 91.7% TM healing and 27 dB ABG postoperatively as compared with 55 dB preoperatively.
In our study, TM was perfectly repaired in all cases and PTA postoperatively was 9.2 dB as compared with 28.9 dB preoperatively. The under-over myringoplasty is a combination of the overlay and underlay techniques, which has been settled with the intent to minimize the disadvantages inherent in the other two techniques[14] with reported about 91%[14] success rate. However, serious complications such as postoperative infection, anterior blunting, and recurrent cholesteatoma could happen with under-over tympanoplasty.
In our study, the performed audiometric tests at the 3rd postoperative month documented that the mean ABG decreased by 20 ± 1 dB.
The usage of the cartilage in tympanoplasty to secure the anterior edge of the graft in large TM perforation, although it offers support to the graft but it has disadvantages of need another dissection to obtain the cartilage as well as it affects hearing.
In this study, we used underlay myringoplasty and gaining its major advantages such as the avoidance of blunting and graft lateralization, because the TM heals at the right level in relation to the annulus and the ossicles and it is easier to be learned than other methods.[3,17] Moreover, we used temporalis fascia as a grafting material that does not reduce middle ear space. We preferred postauricular approach to facilitate access to the anterior annulus. We solve the challenge of limited part of contact between the graft and remaining TM in subtotal perforation by using a second graft on top of the first one anteriorly with gelfoam support in the middle ear.
The sandwich graft tympanoplasty that was described by Farrior[9] by using one layer medial temporalis fascia graft while the second layer of fascia is placed lateral to the handle of malleus on the fibrous TM remnant after removal of its epithelium as an onlay graft. However, they reported developments of graft cholesteatoma, anterior blunting, and lateralized graft. Fortunately, these complications could not be encountered with our double underlay graft and not in concern with the double underlay grafts.
The graft thickness is constantly a concern for the myringoplasty hearing outcome.[4] We preferred to use temporalis fascia for both grafts because of its known advantages; easy availability in enough magnitude, obtain through the same approach, its thickness is comparable to the TM, and with little basal metabolic rate.[4] Moreover, it does not increase the TM thickness to an extent to affect the sound transmission giving optimum sound transmission. But the pressure alteration in the middle ear can result in graft lateralization or medialization ending by failure of myringoplasty. Thus, the average success range of tympanoplasty is 85%–90%.[4,5] Cartilage shares with fascia the mesenchymal tissue nature. However, as cartilage is stiff, it could withstand pressure fluctuation in the middle ear and prevent graft medialization or lateralization. However, cartilage is thicker and stiffer. They mechanically lessen the TM vibratory pattern, contributing to some diminish in the functional outcome, particularly in the higher frequencies.[19]
We have modified this by using two temporalis fascia grafts which are estimated to afford a perfect balance between the stability and the acoustic sensitivity of the TM.
Stage and Bak-Pedersen[20] who supported the over-under technique when utilized for TM perforation anterior to the malleus handle, recorded a 91% success rate in 39 years. A near success was achieved by Kartush etal.[1] (90%) and Babu etal.[21] (84%). Erbele etal.[22] achieved 97% success using over-under cartilage tympanoplasty, but they reported complications such as cholesteatoma and EAC scaring.
In the current study, no new otological instruments are needed and no special training is needed in that challenging cases at high risk for graft failure because of large, subtotal, and total perforation.
There are many advantages of this technique as it is easily performed without need to elevate the epithelial layer of TM remnant and so abolish any risk of epithelial pearl within the middle ear, blunting of TM, or lateralization of the graft. The temporalis fascia graft is easily harvested with enough amount through the extended postauricular incision as well as its double-layer thickness is ideal for acoustic sensitivity.
CONCLUSION
The double-layer temporalis fascia graft is effective for both postoperative graft taking and hearing improvement for subtotal (Grade 4) TM perforation. A study with large number of patients for further evaluation is recommended.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
Acknowledgment
We would like to thank Mariem Ahmed Abdel Fattah for her help in drawing the illustrated diagram.
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