|Year : 2015 | Volume
| Issue : 3 | Page : 186-189
Comparison of canal wall incisions for tympanoplasty for large central perforations
Sohil I Vadiya, Saumya K Shah, Mamta Chaudhary
Department of ENT, Pramukh Swami Medical College and Shree Krishna Hospital, Karamsad, Gujarat, India
|Date of Web Publication||17-Jul-2015|
Sohil I Vadiya
Department of ENT, Pramukh Swami Medical College and Shree Krishna Hospital, Karamsad - 388 325, Gujarat
Source of Support: None, Conflict of Interest: None
Aim and Objective: To compare surgical outcomes with different canal wall incisions used in common practice for tympanoplasty for large perforations. Materials and Methods: Totally 88 patients included in the study and three groups formed. Group A consisted of 35 patients and the vascular strip incision with anterior tucking (VSAT) technique used in these patients. Group B consisted of 31 patients and the tympanometal flap with anterior tucking (TMFAT) technique used in these patients. Group C had 22 patients and the near full cuff (NFC) technique used in them. Results: Success rate of 97.15% observed for Group A, 93.55% observed for Group B and 86.36% observed for Group C patients. Most of the patients in Group A had healing time <4 weeks, whereas most patients in Group C had more than 5 weeks of healing time. Granulations were not seen in Group A, whereas 3 among Group B and 4 among Group C patients developed granulations. Canal wall sagging was seen in 1 among Group A, 2 among Group B and 4 among Group C patients. The average hearing gain in terms of improvement in air-bone gap for Groups A, B and C have been 19.62, 19.25 and 17.35 db, respectively. Conclusion: The VSAT is the method of choice in terms of better success rates and minimum canal skin related complications in postoperative period. The VSAT also provides good exposure during surgery. Hearing gain in Group A is significantly better than Group C (P = 0.023).
Keywords: Canal wall incisions, Tympanometal flap, Tympanoplasty, Vascular strip incision
|How to cite this article:|
Vadiya SI, Shah SK, Chaudhary M. Comparison of canal wall incisions for tympanoplasty for large central perforations. Indian J Otol 2015;21:186-9
| Introduction|| |
Large perforations of the tympanic membrane (TM) have always been more difficult to repair and require modification in technique in many aspects. There are several ways in which canal wall incisions are placed during tympanoplasty. For large perforations, it is very important to provide support to the graft material by additional canal incisions in order to avoid any residual perforations. In doing so, problems of granulations and canal skin edema or sagging are frequently encountered. Gérard et al.  have described a technique without canal skin incisions. According to Gérard et al. Most tympanoplasty techniques require skin incision of the external auditory canal (EAC). This step is not without the morbidity and postoperative complications such as delayed healing, granulation tissue, lateralization, blunting, and iatrogenic cholesteatoma.
We have studied the three basic concepts of canal wall skin incisions most frequently used for tympanoplasty. Anterior tucking is done in all the cases.
| Materials and Methods|| |
Patients who had a TM perforation >5 mm diameter in any dimension were included in this study. The exclusion criteria had been evidence of retraction pocket, or a marginal perforation, or ossicular deformity or any evidence of attico - antral disease. Complete clinical examination and pure tone audiometry done for all patients. Perforations dry for more than 3 weeks were included in the study. The size of perforation was measured by using a graph paper under microscope [Figure 1]. This gives an approximate estimate of the size of the perforation. Postauricular skin incision used in all patients. Total 88 patients were included in the study. The patients were divided into three groups. Group A consisted of those patients where "vascular strip incision + anterior tucking" (VSAT) technique was applied. Group B consisted of those patients where "tympanometal flap + anterior tucking" (TMFAT) technique was applied. Group C consisted of those patients where "near full cuff" (NFC) technique was applied. The decision of doing any of the three methods was taken by randomization. In all these patients, the underlay method of grafting used where the graft was placed lateral to the handle of malleus after separating the handle from the remnant of the TM. Temporalis fascia used as the grafting material in all these patients. Only the cases where the ossicular chain was intact (type I) were included in the study.
The VSAT technique includes a transmetal creation of two vertical and one horizontal incisions in the skin of the posterior wall of the EAC. The horizontal incision is just lateral and parallel to the annulus. The two vertical incisions are placed at 12 o'clock position superiorly along the tympano - squamous suture line and 6 o'clock position inferiorly along the tympano - mastoid suture line.  The horizontal incision is joined with these two vertical incisions. This will create a wedge shaped strip of posterior canal wall skin which will be reflected out of the canal and retracted along with the pinna. The anterior tucking is done using a small horizontal incision (approximately 3 mm) in the superior part of the anterior wall of the EAC, just lateral to the annulus. Through this incision, the annulus is raised, and a small part of temporalis fascia is pulled up to rest between the canal skin and the bone of anterior EAC. This is supposed to prevent medialization of graft.
For Group B patients, after the postauricular incision, a meatotomy incision was kept in the skin of the posterior wall of EAC. This incision would be just medial to the level of the spine of Henle. Through this horizontal incision, the TM is visualized and rest of the posterior canal wall skin was raised as tympanometal flap (TMF) after putting release vertical incisions at 12 o'clock and 6 o'clock. Anterior tucking done in the same way as done in VSAT technique.
For Group C patients, meatotomy incision was kept in the skin of the posterior wall of EAC and the horizontal incision over anterior canal wall was extended inferiorly to meet the 6 o'clock vertical incision. Superiorly, this horizontal incision extends till 10 o'clock in a left ear and 2 o'clock in the right ear. Here, the graft is placed in such a way that a part of the graft lies between the skin and bone of the EAC over all sides except from 10 to 12 o'clock in a left ear, in order to support the graft over more than 270° circumference.
Gelfoam kept in the middle ear and in the EAC in all patients. Packing in EAC done for all patients. The patients are instructed to come for regular follow-up for at least 6 months.
| Results|| |
35 patients (19 males and 16 females) were included in Group A, 31 patients (18 males and 13 females) in Group B and 22 patients (13 males and 9 females) in Group C. The patients were examined for evidence of granulations, canal wall sagging, residual perforation, hearing gain, healing time and evidence of any retraction pocket or cholesteatoma [Table 1]. No lateralization of the graft seen in any of the patients.
|Table 1: Occurrence of complications and hearing gain in the three groups|
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Among the Group A patients, none developed any granulations, whereas 3 (9.68%) among the Group B and 4 (18.18%) among the Group C developed granulations in EAC at 3 weeks of surgery. 1 in Group B and 2 in Group C required follow-up for more than 3 weeks for these granulations.
Canal wall sagging
The canal wall skin becomes edematous or loose and it does not stick well to the underlying bone. This creates a narrowing of canal. Such a problem was seen in 1 (2.85%) patient among Group A, 2 (6.45%) patients in Group B and 4 (18.18%) patients in Group C. Two of these Group C patients with canal wall sagging developed residual perforation at 8 weeks.
1 (2.85%) patient in Group A had a small pinpoint residual perforation at 8 weeks after surgery, which healed with chemical cauterization. Hence, the graft take up rate for Group A patients has been 97.15%. 2 (6.45%) patients in Group B had residual perforations at 8 weeks after surgery, 1 of them had granulations. In Group C, 3 (13.64%) patients had a residual perforation at 8 weeks and 1 of them required a revision surgery. Success rate for Group C patients is 86.36%.
The preoperative audiogram is compared with the audiogram at 3 months after the surgery. No worsening of bone conduction threshold indicative of sensori-neural loss seen in any patient in any group. For Group A, the average gain in air-bone gap (ABG) had been 19.62 db. For Group B, the average gain in ABG had been 19.25 db. For Group C, the average gain in ABG had been 17.34 db. No worsening of ABG seen in any patients in any group. Difference between Groups A and C is statistically significant (P = 0.023), whereas between B and C (P = 0.076) as well as between A and B (P = 0.878) are not significant.
Postoperatively, the patients are examined under the microscope for the first time at 3 weeks after surgery. If the ear is dry and healed at that time, then these cases are included in "<3 weeks" healing time. They were instructed to come every week till the ear became completely dry and healthy. In many patients, no granulation or sagging of canal wall or narrowing of canal wall was seen but during follow-up, there used to be moisture present in the canal skin and few areas of greyish pale discoloration [Figure 2] were seen and this was frequently observed with Group C patients. The results of healing time are depicted in [Table 2].
Only the patients where no residual perforation seen were included in the healing time assessment. Most of the patients in Group A (14 out of 34) had a dry healed ear in <3 weeks time. For Group B, 12 out of 29 and for Group C, 3 out of 19 cases had healing time <3 weeks. 11 out of 34 in Group A had complete healing in 3-4 weeks' time, whereas most of the patients in Group B had complete healing in 3-4 weeks' time. Almost all cases had complete healing by 6 weeks, except for 4 cases in Group C where more than 6 weeks were required for complete healing. The data suggest that healing is quicker with vascular strip incision and slower for NFC technique.
For Group A patients, the most difficult step was to create the vascular strip in the first step. Rest of the steps are easier as it provides the best exposure as the posterior canal skin is out of view. For Group B patients, most of the steps do not pose significant difficulty and exposure provided is moderate. For Group C patients, exposure is limited due to the canal skin being in the picture all the time. The technique of elevating a big skin flap without any tears is also demanding. Putting the graft lateral to handle of malleus has many advantages, as described by Kartush et al.  They have mentioned that the chances of medialization are minimal by doing so as the handle provides good medial support and there is increased the overlap of the graft and drum remnant. In our study, we have placed the graft lateral to the handle of the malleus in all cases of all groups. For this, it is important that the handle has to be made completely free of any remnant of the TM [Figure 3].
|Figure 3: The appearance of handle of malleus after separation from all attachments of ear drum|
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No evidence of retraction pockets or postoperative cholesteatoma seen in any patients in this study.
| Discussion|| |
The use of vascular strip incision has been advocated by many otologists. We have combined anterior tucking step with this technique to give extra support anteriorly for large perforations.
Mokhtarinejad et al.  have described a technique of circumferential subannular grafting with good results. They have concluded that underlay tympanoplasty with elevation of the annulus away from the sulcus tympanicus in the anterior sharp tympanometal angle and placement of the graft between it and anterior bony canal is not associated with increased risk of blunting and lateralization of the graft, if that sharp angle is adequately restored.
Roychaudhuri  has described a three flap technique with three incisions in the canal at 1 o'clock, 11 o'clock and 6 o'clock positions. The incision at 6 o'clock position cuts through the annulus tympanicus.
Lee et al.  have described a superiorly based flap for anterior or subtotal perforations with good results.
Cvjetkovic et al.  have made a quantitative analysis of vascularization after two basic incisions of tympanoplasty namely the TMF incision and the vascular strip incision and found out that there were no significant differences in vascularization of auditory canal skin between TMF and VS patients from one side and the control group on the other side.
Rogha et al.  have compared two methods of TM grafting when graft materials medial or lateral to the malleus and found that the hearing results and success rates are very much similar in both these techniques. In their study, the graft material is pierced in a near central part of the graft, and they lodged so that the malleus handle projects through the graft perforation in a medial to malleus group patients.
In our study, the annulus tympanicus was never cut in any of the three groups and underlay technique with lateral to handle of malleus grafting has been done in all cases. This provides good support laterally and medially and lateralization or medialization not seen in any of the cases.
| Conclusion|| |
For large perforations of the TM, the VSAT technique has the best success rates and minimal canal skin related complication rates with comparatively quick healing. The TMFAT gives good success rates and is comparatively easy to perform. The NFC technique appears more appealing during surgery, but the problems of granulations and canal wall sagging are more as compared to other techniques. The success rate is acceptable for NFC, but the healing time is higher than the other techniques. Hearing gain in Group A is significantly better than Group C with P value being 0.023.
| References|| |
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Kartush JM, Michaelides EM, Becvarovski Z, LaRouere MJ. Over-under tympanoplasty. Laryngoscope 2002;112:802-7.
Mokhtarinejad F, Okhovat SA, Barzegar F. Surgical and hearing results of the circumferential subannular grafting technique in tympanoplasty: A randomized clinical study. Am J Otolaryngol 2012;33:75-9.
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Cvjetkovic N, Velepic MS, Velepic MM, Komljenovic D, Zauhar G. The quantitative analysis of the vascularization following two basic auditory canal skin incisions. Coll Antropol 2003;27:279-84.
Rogha M, Berjis N, Taherinia A, Eshaghian A. Comparison of tympanic membrane grafting medial or lateral to malleus handle. Adv Biomed Res 2014;3:56.
[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2]