DISCUSSION
The major difference between Microscopy and Endoscopy is the surgical view. Tarabichi et al reported that the view during microscopic surgery is defined and limited by the narrow segment of the ear canal[2,3]. By contrast transcanal endoscope bypasses the narrow segment of the ear canal and provides a wide view with 00 endoscopes. Furukawa et al [4], Lade et al[5] and Harugop et al [6]conducted studies to compare the microscopic and endoscopic views tympanoplasty. They reported that in the microscopy groups, the tympanic annulus was not completely visualized in 17%to20% of patients, thus requiring canalplasty. However, in the endoscopy groups, the tympanic annulus was completely visualized; hence, no patient required canalplasty. Ayache [7] reported an even higher rate of 73% of patients in whom anterior perforations of the tympanic membrane were poorly visualized.
Comparing the success rates of microscopic and endoscopic tympanoplasty is often the main concern. Success rates of 90% to 95% for microscopic myringoplasty have been reported [8,9]. Similar success rates of 80% to100% have also been reported for endoscopic myringoplasty [10,11,12] Harugop et al and Lade et al compared the success rates of microscopic and endoscopic myringoplasty and reported no difference. The success rate in our study was 86.6% and the AB reduction to <10 was in 63.3% and 10-20 DB reduction was 33.3% of patients. In 2008, Satyawati Mohindra et al. did 49 cases of myringoplasty and 6 cases of Ossiculoplasties through the transcanal route using rigid endoscopes. The success rate regarding perforation closure was 91.5% and average air bone gap improvement was 22.24 dB in the myringoplasty groups [13]. Ahmed ELGuindy (Tanta, Egypt) has evaluated the role of the rigid endoscope in the management of 36 cases of dry central perforation of the tympanic membrane. The graft uptake rate was 91.7% and air bone gap was closed to less than 10 dB in 83.3% [14].
Endoscopic myringoplasty carries several advantages over the Microscopic myringoplasty, most important it carries minimal scar which is especially beneficial for the females. Shaving is not required in any of these cases. Endoscopy has several disadvantages in ear surgery compared with microscopy. First, the endoscope must be held in one hand, and only the other hand is free to operate; this procedure is particularly cumbersome when bleeding obscures the view of the operating field. In addition, endoscopy provides a monocular view, which causes the loss of depth perception compared with the binocular view provided through microscopy. Moreover, endoscopic myringoplasty still requires more training experience [ 2,3,11]. We partially disagree with the above statement as most of the endoscopic surgeries are done single handed so the required expertise is nothing special for endoscopic myringoplasty. To us there are two most important requirement others than the better hand control, one is a bloodless which is achieved by sufficient canal infiltration with 1:2 Lakh Xylocaine with Adrenalin and the other is dry temporalis fascia graft which makes the manoeuvre of the graft easier. As far as the learning curve of the post graduates is concerned its same as the other endoscopic procedure requirement i.e. practice of diagnostic endoscopy in every patient in the OPD. Temporal bone dissections to learn the methods of myringoplasty before doing actual myringoplasty. In our study, endoscopes allowed us close inspection and photo documentation of the tympanic membrane perforation, the drum remnant, the eustachian tube orifice, the middle ear mucosa and ossicular chain. The anatomical variations (tortuous or stenotic ear canal, anterior meatal overhang etc. that hamper the view of entire tympanic membrane during ear surgery were overcome by the use of endoscopes. Moreover, the permeatal route avoided post aural incision, resulting in less operative time and postoperative pain and morbidity. Disadvantages of the endoscopic myringoplasty included the one-handed surgical technique, a loss of depth perception, limited magnification and the need for training [15]. One major safety concerns with endoscopic ear surgery is excessive heat dissipation. This was evident only when a xenon light source was used. Adequate illumination of the middle ear space can be accomplished with lower settings on the regular light source (because of the size of the cavity) without the need of the xenon systems. Also, the tip of the endoscope requires continuous cleaning with anti-fog solution, which probably helps in cooling the endoscope
The endoscopic technique is the future of myringoplasty and tympanoplasty. With results similar to the microscopic techniques and the added advantages, the endoscope may become more popular than the microscope. The endoscope holds the greatest promise in tympanoplasty and cholesteatoma surgery and should increase the utilization of transcanal over post-auricular procedures[16, 17].
CONCLUSION
Panoramic, wide angle, and magnified view provided by endoscope as well as ability to easily negotiate through EAC and uninterrupted picture overcomes most of the disadvantage of microscope. In our study success rate was comparable between endoscopic and microscopic technique. In terms of morbidity and postoperative recovery, endoscope produced better results. Loss of depth perception and one-handed technique are some of the disadvantage of endoscope that can be overcome with practice and use of endo-holder. Thus, endoscopic myringoplasty can be a good alternative of microscopic myringoplasty.