|Year : 2020 | Volume
| Issue : 2 | Page : 80-84
Endoscopic transcanal stapedotomy: Our experiences at a tertiary care teaching hospital of Eastern India
Santosh Kumar Swain1, Alok Das1, Bulu Nahak1, Jatindra Nath Mohanty2
1 Department of Otorhinolaryngology, IMS and SUM Hospital, Siksha “O” Anusandhan University (Deemed to be), Bhubaneswar, Odisha, India
2 Medical Research Laboratory, IMS and SUM Hospital, Siksha “O” Anusandhan University (Deemed to be), Bhubaneswar, Odisha, India
|Date of Submission||07-Jun-2019|
|Date of Decision||24-Jul-2019|
|Date of Acceptance||20-May-2020|
|Date of Web Publication||17-Jul-2020|
Prof. Santosh Kumar Swain
Department of Otorhinolaryngology, IMS&SUM Hospital, Siksha “O” Anusandhan University (Deemed to be), Bhubaneswar, Odisha
Source of Support: None, Conflict of Interest: None
Introduction: Although operating microscope is used worldwide for stapes surgery, the use of endoscopes would provide much benefit such as good panoramic view of middle ear and easy accessibility of the oval window area, stapes, and facial nerve. Objective: We aimed to analyze our experiences of endoscopic transcanal stapedotomy performed at a tertiary care teaching hospital of Eastern India. Materials and Methods: This prospective study was done at the Department of Otorhinolaryngology between March 2017 and April 2019. The patients were diagnosed as having otosclerosis with fulfilling the selection criteria. All underwent endoscopic transcanal stapedotomy. Results: Out of 52 patients those underwent endoscopic transcanal stapedotomy, there were 28 females and 24 males. The mean age was 32.40 years. The mean operation time was 35.43 min. The mean preoperative air–bone gap (ABG) was 34.84 dB, whereas the mean postoperative ABG was 9.81 dB. Tympanomeatal flap tear was seen in one case. One case showed chorda tympani injury and two patients presented with vertigo after surgery. No other complications were seen after endoscopic stapedotomy. Conclusion: The important advantages of endoscopic stapedotomy are good-quality visualization with identification of vital parts of the middle ear cleft, minimal handling to the chorda tympani nerve with almost no curettage of the scutum. The development of endoscopic ear surgery techniques promises the change the way we approach for stapes surgery. The wide field view of endoscope helps the surgeon to visualize better the middle ear recess, especially oval window niche and stapes.
Keywords: Endoscopic stapedotomy, otosclerosis, stapes, transcanal approach
|How to cite this article:|
Swain SK, Das A, Nahak B, Mohanty JN. Endoscopic transcanal stapedotomy: Our experiences at a tertiary care teaching hospital of Eastern India. Indian J Otol 2020;26:80-4
|How to cite this URL:|
Swain SK, Das A, Nahak B, Mohanty JN. Endoscopic transcanal stapedotomy: Our experiences at a tertiary care teaching hospital of Eastern India. Indian J Otol [serial online] 2020 [cited 2020 Oct 26];26:80-4. Available from: https://www.indianjotol.org/text.asp?2020/26/2/80/289951
| Introduction|| |
Stapes surgery is done at a very fragile anatomical area where there is a risk of injury to the chorda tympani nerve, incus, facial nerve, and tympanic membrane. There is a chance of sensorineural hearing loss due to incorrect surgical procedure. The possible complications, microscopic visual field, and complex anatomy of the middle ear are causes of concern in stapes surgery. Although rigid endoscopes were used for ear surgeries over the last 15 years, their role has been limited in the treatment of middle ear infective disorders and otosclerosis. The endoscope provides a wide-angle and high-resolution image which allows improved visualization of the middle ear cleft in comparison to the operative microscope. The endoscope helps otolaryngologists to bring angled optics and a high-contrast light to the middle ear, avoiding a postaural approach and extended bony dissection. The important point for consideration during stapes surgery under an operating microscope is seeing the stapes suprastructure. Surgeon often unable to observe the anterior crus of the stapes via transcanal approach under a microscope which may force the surgeon to do blindly fractures of such part. Many times, excessive removal of the bone is required for better visualization of the middle ear structures and foot plate area and may result in subluxation of the incus. After introduction of 3 charge-coupled device camera, high-definition video monitors and recently small diameter fiberoptic and modern endoscopes provide high-resolution images of the middle ear cleft structures and enable minimally invasive transcanal approach for middle ear surgery or stapes surgery. Here, we assess the use of rigid endoscope by transcanal route for stapes surgery and find out the outcome and possible pros and cons of this technique.
| Materials and Methods|| |
This study involved a prospective analysis of patients with conductive hearing loss those who were diagnosed as otosclerosis and who underwent stapedotomy by endoscopic transcanal approach. Fifty-two patients were diagnosed as having otosclerosis and underwent endoscopic transcanal stapedotomy in this tertiary care teaching hospital during March 2017–April 2019. There were 28 female and 24 male patients with a range from 29 to 48 years. Institutional ethical committee of our institute approved this study where only endoscopic transcanal stapedotomy patients were included. Diagnosis of the otosclerosis was based on clinical history, otoscopic examinations, and audiological investigations such as pure tone audiometry and tympanometry. Patients of otosclerosis who have large external auditory canal were randomly selected for this study and patients with narrow external auditory canal were avoided by transcanal endoscopic surgery and excluded from this study. Pure tone audiometry was done in all cases preoperatively and postoperatively with documentations of bone conduction thresholds and air–bone gap (ABG) at the three speech frequencies of 500 Hz, 1000 Hz, and 2000 Hz. Postoperative pure tone audiometry was performed at 1, 3, 6, and 12 months following surgery. ABG closure within 10 dB was called as success, whereas closure to within 20 dB called as improvement.
All the surgical procedures were done under local anesthesia and surgeries were performed by senior authors. The patients were placed in same position as in conventional ear surgeries done under an operating microscope. The video monitor was placed in front of the surgeon. In this transcanal approach, insertion of speculum into ear canal was usually done for better visualization. However, in our series, we sutured anterior and posterior wall in such manner, the meatus is widened, and accessibility to the middle ear will be easier [Figure 1]a and [Figure 1]b. Hence, surgeon's hand will not be used anymore for holding the speculum. We used all instruments as in conventional ear surgeries, except for the use of 3 mm diameter and 14 cm long rigid endoscope with 0–30°, curved tip microscissors, and curved microaspirators. The external auditory canal was injected with 1% lidocaine along with 1:100,000 epinephrine. Transcanal endoscopic stapedotomy was undertaken using rigid endoscopes in all cases of this study. Routine otological microinstruments, angled picks, curved scissors, and forceps were used in this procedure. Trimming of the ear canal hair was done before starting endoscopic surgery to reduce smudging of endoscope. The surgeon holds the endoscope in the left hand with instruments in the right hand and tried to avoid the endoscope holders as it may cause injury in case of unexpected patient movement.
|Figure 1: Suturing technique for widening of the anterior wall (a) and posterior wall (b) of the external auditory canal meatus |
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Posterior tympanomeatal flap was elevated transcanally with the help of 0° endoscope and transposed anteriorly. All the procedures were performed with a 0° endoscope, whereas a 30° endoscope was needed for better visualization of oval window niche, anterior crura of the stapes, tympanic segment of the facial nerve, and pyramidal eminence. The endoscopic picture of the middle ear was excellent without drilling/curettage of the scutum [Figure 2]. Stapes fixation was assessed by gentle testing of ossicular chain mobility. Stapedius tendon was cut by curved microscissors and stapes was dislocated from the incus at incudostapedial joint. The anterior and posterior crus of the stapes were fractured carefully and suprastructure was taken out. The distance between medial surface of the long process of incus and footplate of stapes was measured for required size of prosthesis. A hole was made in footplate with a skeeter microdrill by 0.5 mm diameter diamond burr. Teflon piston prosthesis (0.4/0.5 mm diameter/4.5 mm length) was placed in fenestra and fitted along the long process of the incus [Figure 3]. The ossicular chain mobility was ensured by palpating malleus. We avoided repeated suctions after making opening of footplate, in order to avoid complications such as vertigo and damage to cochlea. The malleus was palpated to find out head fixation and make sure that the entire ossicular chain moves all the way to prosthesis. The footplate area was sealed with small pieces of dry gel-foam placed by crocodile forceps. The tympanomeatal flap was repositioned and ear canal was filled with gel-foam soaked with topical ear drops containing antibiotics.
|Figure 2: Endoscopic picture of the middle ear after elevation of tympanomeatal flap|
Click here to view
| Results|| |
Out of 52 patients who participated in this study, there were 28 female and 24 male patients who underwent endoscopic transcanal stapedotomy. Stapedotomy was performed on the right ear in 34 patients and left ear in 18 patients. The mean age was 32.40 years. The mean operation time was 38.43 min. The mean preoperative ABG was 34.84 dB, whereas the mean postoperative ABG was 9.81 dB. Footplate and anterior and posterior crura of the stapes were visible with endoscopic picture. Out of 52 cases, house curette was used for bony curettage in 2 cases only [Table 1]. Tympanomeatal flap tear was seen in one case and immediate tympanoplasty was done with temporalis fascia which healed after 1 month. Temporary impairment of taste and dysgeusia was found in one case due to manipulation of the chorda tympani nerve. No case of incus subluxation was reported in this study. Two patients showed mild and transient vertigo after surgery which were controlled by conservative treatment [Table 2]. In these two cases of vertigo, there was difficulty in placing of the prosthesis during surgery. No postoperative sensorineural hearing loss was recorded in this study. All the patients who underwent endoscopic stapedotomy reported subjective improvement of hearing during and after surgery. Out of 52 patients, three patients had obliterative footplate. One patient showed dehiscent tympanic portion of facial nerve. A 4.5 mm size diameter prosthesis was used in 48 cases and 4.75 size used in 4 cases. Fifty patients were discharged 2 days after surgery as per routine poststapedotomy protocol which is accepted in our department. The rest two those presented with vertigo discharged after 5 days of surgery. Pure tone audiogram was done in all cases after 3 months of surgery where the average postoperative ABG was within 10 decibel.
| Discussion|| |
Stapedotomy is usually done for the treatment of otosclerosis. It can be technically difficult and challenging for surgeons due to anatomic variations in size, shape, configuration, and irregularity of the external auditory canal. After introduction of the classical stapes surgery for otosclerosis by Shea, several variations have been described in the medical literature. However, they all use the operating microscope for stapes surgery. Nowadays, there are few publications showing the possible benefits of using endoscopes in ear surgery, especially due to a better view of the structures in the middle ear cleft. In our study, we performed stapes surgery with endoscope only via transcanal approach. There are several difficulties encountered during stapes surgery and these include exposure of the oval window niche, short chorda tympani nerve, dehiscent facial canal with bulging toward oval window area, and narrowing of the oval window niche by otosclerotic focus. The use of endoscope for middle ear was described long back in 1967. Otoendoscopy is now used as a diagnostic tool for middle ear diseases. Types of middle ear surgery are often better planned on the basis of endoscopic findings. Despite the extensive use of the endoscopy for middle ear diseases, still little was mentioned in the medical literature about its use in stapes surgery. The first published report for use of endoscope in stapes surgery was by Poe in 2000. This was the first and only literature where laser-assisted endoscopic stapes surgery described. Further studies are required for use of endoscope in transcanal approach of stapes surgery. Endoscopy will definitely revolutionize stapes surgery, particularly after improvement of micro-instrumentation. Cutting of the stapedius tendon, incudostapedial joint dislocation, and fracture of the crura of the stapes are easier with endoscope than microscope. Excellent exposure of the stapes footplate without removing the bony overhanging or touching the chorda tympani is usually possible with endoscope. During microscopic stapedotomy, in almost all cases, there is requirement of removal of the medial bone segment of posterosuperior wall of external auditory canal. This bony removal can be done by using curettes or burr with micromotor. During bony removal, there is a chance of manipulation of chorda tympani nerve or even complete section of this nerve, subluxation of incudostapedial joint, and damage to facial nerve when excess burring is required. However, making perforation on the footplate and insertion of the prosthesis were both easier by microscope than endoscope. This can be explained by direct axis of the vision offered by microscope in comparison to endoscope. Before starting endoscopic stapes surgery, senior authors of this study performed stapes surgery under microscope, where in almost all the cases, there is a need for partial curettage of the medial bone segment on the posterior wall of the bony external acoustic meatus. The removal of bone can be done using delicate curettes or a burr with microdrill. However, in this situation, some degree of chorda tympani nerve manipulation or even complete damage of this nerve occurs. In some patients, this type of technique may be so difficult due to anatomical reasons, leading to damage of the facial nerve when further burring of the bony part is needed. In this study, with fully endoscopic stapes surgeries, we got excellent visualization by 0° and 30° angled endoscope at the oval window niche, pyramid, facial nerve, and long process of incus without cutting or drilling the posterior wall of the external bony acoustic meatus. No patients of this study had their chorda tympani nerve manipulated as during raising tympanomeatal flap; this nerve is in front of our visual field, blocking us for seeing the oval window area. We handled the chorda tympani nerve carefully, but out of 52 patients, one patient of this study complained temporary alteration of the taste. One study stated that a better view of the anterior crus was given by the endoscope which helps fracture under direct visualization and avoid blind maneuvers, so bringing chances to fracture the foot plate into almost nil. In this study, there was good visualization of the anterior and posterior crura achieved in all our cases, which helped to perform safe fracture and removal of suprastructures. Moreover, use of endoscope provides a better picture on the monitor which will be very helpful for teaching to residents and trainees. Several studies showed that there is no statistically significant difference between microscopic and endoscopic stapedotomy with regard to postoperative ABG. However, they showed that endoscopic stapedotomy is technically safe, feasible, and promising. The main advantage of the endoscopic stapes surgery is excellent vision. On the other hand, the demerits are lack of stereoscopic vision, working with only one hand, and the learning curve. The important favorable outcomes in endoscopic surgery are reduced injury of the chorda tympani nerve and tearing of the tympanic membrane. Endoscope light can cause high temperature in middle and inner ear. An animal study showed that xenon and halogen light caused high temperature at oval window area, which can easily pass to the cochlea by perilymph and leads to sensorineural hearing loss. Movement of the endoscope using light-emitting diode light and reduced operative time may avoid middle ear from high temperature. In our study, we did not get any sensorineural hearing loss. It is recommended to keep the power of the light source more than 5 mm from inner ear structures and frequently taking endoscope out of the middle ear and do suction irrigation for making cooling of the middle ear. The light source should be no more than 50% intensity for ensuring patient safety. Although this study is not a comparative study, endoscopic approach provides several advantages such as panoramic view of the important structure in the middle ear, especially that of the oval window area without curetting bony scutum.
The important limitation of endoscopic transcanal endoscopic ear surgery is one-handed surgery. Ear surgeons routinely look binocularly and directly into the operated ear through microscope and utilize both hands for eliminating pathology, suctioning, hemostasis, and ossicular reconstruction, while one hand is occupied with endoscope and another hand performs other activities during endoscopic sinus surgery. Endoscopic ear surgeons see a monitor and this can result in a loss of depth perception which later compensated with greater experience. Assistance may be required especially during the surgeon's initial period of endoscopic procedures. Right-handed surgeons feel more comfortable when performing right ear surgery and relatively difficulty for making hole on footplate and keeping prosthesis in the left ear which can be overcome with more training. The absence of stereoscopic vision is not considered as a drawback. The endoscopic approach can be done in unfavorable external or middle ear anatomy, revision cases or bilateral stapedotomy, in patients with already impaired taste sensation, patients with food-smell or taste-related occupations, and patients those taste for food contributes appreciably to their quality of life.
There are some controversies regarding safety and efficiency for endoscopic approach toward stapedotomy such as controlling hemorrhage, anti-fogging methods, endoscopy-induced thermal injury, and loss of depth perception which provide reluctance to some otologists for adopting this technique. In addition to these difficulties, single handed surgery, cost of endoscopic equipment, requirement of specialized training, and adequate experience can further deter the otologists who already practicing stapedotomy under microscope. Similar difficulties were also raised in previously published literature, particularly challenge of one-handed surgery and learning curve create difficulty in implementing the endoscopic approach for stapes surgery. However, endoscopic transcanal stapedotomy in experienced hand is a safe and reasonable approach. Indeed, the transcanal endoscopic approach for stapes surgery is an established technique by an experienced hand. Here, we had not done any comparative study between endoscopic approaches with microscopic stapedotomy as in our center stapedotomy was only done by endoscopic approach by senior authors. However, this approach in our study seems to provide several advantages such as better visualization during procedure especially structures such as oval window niche, crura especially anterior crura, and without curettage of the posterosuperior bony wall (scutum) of external auditory canal.
There are certainsituations where beginners should be careful during endoscopic transcanal stapedotomy. Surgeons should be expert in handling the endoscope and also expert in endoscopic tympanoplasty before starting this surgery. Accidental movements of endoscope may cause accidental trauma by the tip of the endoscope on important structures in the external auditory canal and middle ear. In the external auditory meatus, special care should be taken to avoid unnecessary bleeding caused by trauma. In the middle ear, special care must be taken considering all important structures such as ossicular chain, the facial nerve, and others. To avoid such injury, the surgeon must keep the endoscope in the surgical field when not looking directly to the screen/monitor. The tips of the endoscopes usually generate hit by the light source. Hence, special care must be taken to the tip of the endoscope, as it may have a high temperature which causes damage to the important structures.
| Conclusion|| |
The wide field view of the endoscope helps the surgeon to visualize the different recesses of the middle ear cleft. Endoscope has a distinct advantage over the narrow field view of the binocular microscope which is a line-of-sight instrument. Endoscopic stapedotomy has several benefits such as good visualization, easy accessibility to the foot plate of stapes, oval window niche, and facial nerve. Endoscopic technique also helps avoid removal of the scutum and manipulation of the chorda tympani nerve. In our study, all the stapedotomy surgeries were performed with help of endoscope where all relevant anatomical structures were visualized without any difficulty and minimal to no complications.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2]