Aurists noticed the ability of the endoscope to look around corners. It has high resolution and can reduce the trauma and pain of the patient. It can also keep the mastoid process and osseous external auditory meatus behind intact. The ear endoscope can be used by aurists to identify hidden parts that the microscope cannot recognize, such as the epitympanum, facial recess, and sinus meningioma angle. Besides, it can share the endoscope system with the nasal endoscope.
However, there are some disadvantages. The ear endoscope can only be operated with one hand and will cause thermal damage. Its lens can be easily blurred by heat gas or blood. Besides, it is not suitable for patients with external auditory canal stenosis, and cannot be used simultaneously with an electric drill.
We have summarized some experiences that can make the surgery more smoothly. 1) Making a 270-degree circular incision about 10mm near the tympanic ring through the external auditory canal. Sometimes the second incision (intertragic notch) or the third incision (cavity of auricular concha) is supplemented according to the intraoperative situation. 2) Gelatin sponge can be used to avoid skin flap injury. 3) In order to reduce bleeding during the surgery, tungsten needles can be used to get incisions, 1:10 adrenaline cotton wool balls can be used for pressure hemostasis, and the extremely thin BIPOLAR COAG can be used to get local hemostasis. 4)Bone needs to be drilled under saline to reduce thermal injury. 5) The use of suction or irrigation will help to reduce the impact on the visual field. 6) In order to explore the operative cavity completely, we recommend the following sequence of exploration: mesotympanum, hypotympanum, anterior tympanum, tympanic antrum, mastoid process, epitympanum, and rear tympanum. The key parts are epitympanum, facial recess, sinus meningioma angle, and tensor tympanic fold. 7) Ear endoscope is usually operated with one hand, and it can be operated with two hands when the endoscope holder or assistant is able to hold the endoscope. However, the surgeon needs to communicate with the assistant continuously, so that the field of vision can be suitable for him. 8) The most important thing is that when vision is limited, a microscope should be used to assist endoscopic ear surgery in time. When the lesions involve the upper tympanum or mastoid, microscope-assisted endoscopic ear surgery can provide a lot of help. 9) Postoperative attention should be paid to facial paralysis, cerebrospinal fluid otorrhea, hemorrhoea, and thrombus.
Recently, Professor Hou of the General Hospital of the People's Liberation Army put forward the core concept of minimally invasive ear surgery, which is called functional middle ear surgery. It means that based on clearing the lesions of the middle ear cavity, the mucosa and air chamber system of the mastoid process should be preserved as much as possible. Professor Hou recommended checking the ventilation channel from the Eustachian tube to the middle ear cavity to establish a stable air cavity and achieve satisfactory postoperative results [3].
Endoscopic ear surgery first appeared in the 1960s [4]. In the 1980s, endoscopes were widely used for nasal examinations and surgery. In the 1990s, endoscopes began to be gradually used in ear examinations and surgery [5]. In recent years, endoscopes have received widespread attention and have begun to be increasingly used in minimally invasive ear surgeries.
In the literature [6], one group of patients used an endoscope for tympanoplasty, and another group of patients used a microscope. The results showed that there was no significant difference between the two surgical methods in terms of surgical outcome, hearing restoration, recurrence rate, and complications. However, endoscopic ear surgery shortens the surgery time and anesthesia time, and reduces the patient's pain. In the literature [7, 8], 146 cases of endoscopic cholesteatoma resection and tympanoplasty were successfully completed, and the cholesteatoma was completely removed. Although 11 cases relapsed, none of them had obvious complications, and all the grafts survived. In the literature [9], it was found that through endoscopic ear surgery, the probability of disease eradication was significantly increased, resulting in a decrease in the incidence of residual cholesteatoma from 47–6%. Literature [10] systematically reviewed 38 literatures related to endoscopic ear surgery, and found no major complications. In the literature [11], the cochlear implantation using an ear endoscope was successfully completed in 2014. In the literature [12], the Second Affiliated Hospital of Nanjing University performed 113 cases of tympanoplasty using the ear endoscope in 2012, of which 92 cases reached dry ears within half a month to one month. Tympanic pressure gradually improved after 3 to 6 months. Besides, it was found that there was no statistical difference between the endoscopic ear surgery and the microscopic ear surgery in terms of hearing restoration, recurrence rate, and the state of the tympanic membrane. As can be seen from the existing literature that, in general, endoscopic ear surgery is seldomly used in China at present.
In this study, it was confirmed that type I tympanoplasty with one-handed ear endoscope is feasible and effective. All patients reached the state of dry ears, the tympanic membrane of them healed well, the hearing was significantly improved, and no serious complications occurred.
Type I tympanoplasty is an entry-level surgery. Because the anatomy is more intuitive, doctors with less experience are more willing to use an endoscope for type I tympanoplasty. Therefore, endoscopic ear surgeries were more performed in basic hospitals than in high-level hospitals.
In recent years, ear endoscopes have gradually been used in surgeries on the mastoid, temporal bone, inner ear and other parts in China. Further clinical practice is needed to study which other parts of the ear can be operated with the ear endoscope.