Endoscopic Tympanoplasty: Is it Better than Microscopic Tympanoplasty? Our Experience

INTRODUCTION

Surgical procedures that are used for repair of the tympanic membrane and middle ear, respectively, are myringoplasty and tympanoplasty.¹ Any operation involving reconstruction of the tympanic membrane with or without ossicular chain reconstruction is referred to as tympanoplasty. On the other hand, myringoplasty refers to repair of tympanic membrane only. The most widely used and accepted method is underlay graft technique of temporalis fascia or sometimes perichondrium.² The introduction of the operating microscope has enhanced the outcome of myringoplasty by improving the accuracy of the technique.

With the introduction of the endoscope into other branches of surgery, there have been attempts at its utilization in otology. The first published description of imaging of the middle ear by endoscopy was by Mer et al. in 1967.

Endoscopic ear surgery (EES) has remained controversial since its first description in the English literature in the late 1960s.³ Modern microscopes provide excellent views of the surgical field and confer the ability for binocular vision and two-handed surgery, and visualization of deeper recesses in the middle ear is limited. The optical properties of a microscope require an adequate amount of light to reach the surgical plane. As a result, current microscope-based operative approaches frequently necessitate soft tissue retraction and/or bony drilling to adequately visualize the targeted pathology.

In contrast, endoscopes allow for improved visualization, as the light source is located at the distal tip of the instrument, and angled lenses offer a wide perspective of the operative field. Further, transcanal endoscopic approaches transform the external auditory canal into a surgical portal. Due to the relative diameter of the endoscope to the ear canal, however, only one-handed surgery is feasible, thereby making dissection less efficient and more challenging, especially in the case of blood in the operative field.⁴

Further, questions remain as to the long-term safety of extended static application of endoscopes in the middle ear due to the heat generated by these instruments.^5,6

The use of a rigid endoscope for myringoplasty has a significant advantage, as it is simple to use, not only for the examination but also for the repair of the tympanic membrane perforation. This provides a magnified vision and hence enables the surgeon to change rapidly from a close-up to a wide-angle view, just by going closer or by withdrawing the scope. Further, it provides an all-round vision to the surgeon who can rotate the angled endoscope to visualize the deep anterior canal wall, anterior recess, anterior marginal perforations, sinus tympani, facial recess, hypotympanum, and the attic.⁷

MATERIALS AND METHODS

This study was carried out at Mahatma Gandhi Hospital, Jaipur, Rajasthan, from September 2018 to May 2019. In ENT OPD, patients who presented with complain of ear discharge and those who were willing for surgery with their informed and written consent were screened. 256-, 512-, and 1024-Hz frequency tuning forks were used for Tuning fork test, and pure tone audiometry was done to evaluate the type and degree of hearing loss. Hearing loss was calculated by taking the average of A-B gap at frequencies of 500, 1, and 2 kHz.

RESULTS

In this study of 200 cases of central tympanic membrane perforation, successful graft uptake after 3 months in conventional microscopic and endoscopic myringoplasty group was 96% and 92%, respectively (Fig. 2). Average time taken in conventional microscopic tympanoplasty and endoscopic tympanoplasty group was in the 40-minute range (40–50 minutes) and 55-minute range (51–60 minutes), respectively (Fig. 3). Canaloplasty was performed in 12 of 100 patients in the microscopic group as required while in the endoscopic group, canaloplasty was not required in any case (Fig. 4). In our study, average preoperative hearing loss in conventional myringoplasty group was 31.53 dB while in endoscopic myringoplasty group it was 30 dB. Postoperatively, average air–bone gap in conventional myringoplasty group was 16.03 dB, while in endoscopic myringoplasty group it was 15 dB. Average hearing gain in conventional myringoplasty group is 13.96 dB and in endoscopic myringoplasty group is 15.03 dB (Fig. 5). In all, 95% of patients in the endoscopic tympanoplasty group rated their cosmetic result as excellent, whereas in the conventional group, 75% patient rated their cosmetic result as excellent, 22% patients rated their cosmetic result as satisfactory, and 3% patients rated their cosmetic result as poor (Fig. 6). So, endoscopic group of patients had better cosmetic result compared to conventional myringoplasty groups (Fig. 7). Average postoperative hospital stay in microscopic myringoplasty group was 1 day, while in endoscopic myringoplasty group maximum patients were discharged on the same day (Fig. 8). Patients present with postoperative complication such as wound gap in 4 of 100 in microscopic group while none in the endoscopic group (Fig. 6).

DISCUSSION

The main aim of this study was to evaluate the advantage of using endoscopes in ear surgeries over conventional methods of ear surgeries. In conventional tympanoplasty, group time taken was less compared to endoscopic group. As endoscopic surgeries are one-handed surgeries, due to bleeding, achieving hemostasis can be troublesome with endoscopes. In the conventional group, feasibility of using instruments in both hands make it less troublesome. But this can be overcome with expertise of the surgeon. Endoscopes provide a wide and clean surgical field. In endoscopic surgeries, precise canal incision is given. Therefore, manipulation of soft tissue is minimal. As view is magnified and wide bone drilling or canaloplasty is not required, bleeding is less, which subsequently increased effectiveness of this method of surgery as well as reduced postoperative pain and complication, such as infection, delayed wound healing, and scar dehiscence. External incisions, soft tissue dissections, and mastoidectomies can be avoided by using endoscopes in selected cases. Microscopes give limited visualization of deep and hidden spaces involving sinus tympani, epitympanum facial recess, and the attic area.^4,8–10 So, in microscopic techniques, further soft tissue dissection/retraction and bony drilling to obtain a better surgical view are frequently needed.⁴ In any patient of ET group, EAC widening or external incision was not needed. Otherwise, of patients who underwent conventional microscopic tympanoplasty, one-third patients had EAC widening by drilling. Endoscopic ear surgery has several disadvantages over conventional microscopic technique, such as the endoscopic instrument can cause direct injury and thermal damage to the external canal and middle ear.^5,6 Due to heat generation from light source of the endoscope, Kozin et al.⁶ recommended using sub-maximal light intensity and frequent repositioning of the endoscope. No such complications were seen in this study group.

CONCLUSION

The surgical outcome of endoscopic tympanoplasty in terms of successful graft uptake and hearing gain was comparable to the conventional microscope-assisted tympanoplasty. In endoscopic tympanoplasty group, patients had better results in terms of cosmesis and postoperative recovery.

REFERENCES

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