Discussion
Granular myringitis is a chronic, vascular, fibroproliferative and ulcerative dermatitis which involves focal or diffuse areas of the tympanic membrane. It is a frequently encountered problem in otolaryngologic clinic. The clinical presentation is variable from mild, focal de-epithelization of tympanic membrane to diffuse granular involvement of whole ear drum and external ear canal. If left untreated or unsuccessfully treated, the clinical course may continue for months or years.
The etiology of granular myringitis is numerous, but loss of squamous epithelium on the lateral surface of the tympanic membrane is most accepted mechanism as one of the preliminary stages of granulation development. Mohan Bansal [1] suggested the etiological classification of GM as the Primary granular myringitis (idiopathic) & Secondary granular myringitis. Secondary GM separated into Traumatic, infection and the other neoplastic reasons. Our study stands for this etiological classification, 36.1% of GM patient in our study suffered from previous otologic procedure. We had discovered the location of focal GM mostly occurred at the posterior-inferior quadrant (76/130, 58.5%), which is compatible to the site of tympanic membrane manipulation and elevation of tympanomeatal flap during otological surgery.
There are a variety of treatment regimens available in the management of granular myringitis[2]. To date, no single therapeutic regimen has been determined to be successful in the management of granular myringitis. [5] In our study, we compared the effect of caustic agent cauterization and CO2 laser vaporization. We had all patients underwent topical otic drops previous to the surgical treatment at least one month, and the total remission rate was only 22.3% (29/130). Most of the patients treated with ear drops exhibited a prolonged recovery period. It often takes few weeks and recurrence occurred as soon as the eardrop therapy was discontinued. In a study conducted by Jung et al [6], majority of patients experienced resolution of their otorrhea within three weeks after dilute vinegar use. We used BAAG solution in majority of patients, and ciprofloxacin ear drops only for patients with purulent otorrhea. Boric acid is a weak acid with antiseptic character which frequently used in antifungal treatment. It can keep the mild acidic environment of external auditory canal. Levinson [7] admitted that there was no effective local treatment which could successfully cure granular myringitis. Cauterization with chemical agent, such as 5-fluorouracil or trichloroacetic acid had been reported by Atef et al [8] with promising results. Cauterization with 50 percent TAA has been trialled for exuberant granulation tissue. In our study, TAA cauterization group successful rate was 79.2% (38/49) and the recurrent rate was 18.4% (7/38). The definition of success was no local finding on ear drum and symptom free in postoperative four months. It seems that both surgical group has higher successful rate and lower recurrent rate compared with simple topical agents. Fechner et al [9] recommended more aggressive treatment for granular myringitis. They used CO2 laser for refractory myringitis. They suggested that the primary advantage of CO2 laser over traditional treatment was that the laser not only vaporizes the granulation tissue but also stimulates growth of the surrounding disease epithelium. In our study, the successful rate of CO2 laser was 94.9% (37/39) and the recurrence rate was 13.5% (5/37). The successful rate was higher than TAA cauterization group which reached statistical significance (p<0.05). However, the recurrence rate was similar to TAA cauterization group (p = 0.562, >0.05). CO2 laser emits a wave length of 10600 nm and its resurfacing function has been widely used by dermatologist for rhytids and dyschromias. [10] The laser resurfacing technique was used in treating granular myringitis by otologists Cheng et al [10] used CO2 laser for intractable chronic myringitis. Of 30 affected ears, 22 ears demonstrated total resolution and 7 ears demonstrated partial resolution; disease status remained unchanged in only 1 ear. Jang et al [3] used endoscopy-aided laser therapy for intractable granular myringitis and the CO2 laser setting was similar to our study. Eighty-five percent (18/21) were cured after single treatment. No adverse effect on hearing thresholds or other complications were observed. They used CO2 laser equipped with otoendoscopy, providing an unobstructed view, especially at the anterior access. However, it takes more time to set endoscopic equipments. Under microscopy, we can control the surface area and depth of tissue vaporization precisely by varying the laser settings for power, exposure time and spot size. The power can be increased if the operative area is thick. When the given energy level has been applied and the ear drum seems to rupture, the energy level can be lower or the lens adjusted to a defocus setting. El-Seifi and Fouad [11] recommend aggressive surgical treatment approach to granular myringitis as curettage of granulations, elevation of a tympanomeatal flap, cartilage/perichondrium underlay grafting and lateral skin graft coverage of the denuded areas. Recurrence occurred in only 2 of 48 patients. Unfortunately, similar surgical success was not achieved in another smaller series using surgical techniques. [12] 4 of 5 patients developed recurrence. Zhang et al [13] used tympanic epithelial avulsion with overlay myringoplasty to treat 21 severe chronic myringitis cases. All 21 cases were cured after one operation, and no recurrence after two years follow up. Given the variable success of aggressive surgical management of chronic granular myringitis, we suggest the alternative option of CO2 laser resurfacing treatment for cases refractory to medical treatment. The CO2 laser is an effective, minimally invasive technique that can be performed safely and easily by an otolaryngologist. The technique provides a viable alternative to more aggressive surgical treatment approaches in patients with granular myringitis refractory to medical treatment.