There are limited studies describing the surgical and hearing outcomes following endoscopic stapes surgeries, despite the burgeoning interest and excitement in endoscopic ear surgery. Current studies have demonstrated that endoscopic stapes surgery is safe and has similar audiologic outcomes when compared with microscopic stapes procedures. However, preliminary studies show decreased postoperative pain in endoscopic cases compared with microscopic controls. In regards to possible endoscopic advantages, these few studies demonstrate mixed results when comparing the need to remove the bony medial external auditory canal wall to improve visualization and access to the oval window niche.
Key points
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With experience, endoscopic stapes surgery is an effective alternative when compared to microscopic stapes surgery, with similar complication rates and audiometric outcomes.
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To date, 56.0% to 86.7% patients have had closure of their air bone gaps to under 10 dB HL following endoscopic stapes surgeries.
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Postoperative dysgeusia and pain scores appear to be improved in endoscopic stapes surgeries compared with microscopic approaches.
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Introduction
The first published case of use of an endoscope in the middle ear was in 1967, when it was used to visualize the middle ear and the integrity of the ossicular chain through a myringotomy incision. With technological improvements leading to enhanced image resolution, as well as recognized acceptance of endoscopes within the field of rhinology, there has been greater implementation of endoscopes in otologic and neurotologic procedures. Now, almost 50 years after the first endoscopic description of the middle ear, surgeons are utilizing endoscopes to evaluate and remove cholesteatomas, place cochlear implants, remove vestibular schwannomas, and assist with repairing dehiscent superior semicircular canals. Although many of these applications are limited to a few scattered case reports, several endoscopic cholesteatoma studies have highlighted the role endoscopes play in identifying residual disease. Given the endoscope’s wide angle of view and improved visualization of structures parallel to the microscope, it is not surprising that there are several reports describing the role of endoscopes in stapes procedures. This article provides a summary of endoscopic stapes surgery, highlighting the variety of techniques and perceived advantages, as well as audiometric and patient outcomes ( Fig. 1 ).
Introduction
The first published case of use of an endoscope in the middle ear was in 1967, when it was used to visualize the middle ear and the integrity of the ossicular chain through a myringotomy incision. With technological improvements leading to enhanced image resolution, as well as recognized acceptance of endoscopes within the field of rhinology, there has been greater implementation of endoscopes in otologic and neurotologic procedures. Now, almost 50 years after the first endoscopic description of the middle ear, surgeons are utilizing endoscopes to evaluate and remove cholesteatomas, place cochlear implants, remove vestibular schwannomas, and assist with repairing dehiscent superior semicircular canals. Although many of these applications are limited to a few scattered case reports, several endoscopic cholesteatoma studies have highlighted the role endoscopes play in identifying residual disease. Given the endoscope’s wide angle of view and improved visualization of structures parallel to the microscope, it is not surprising that there are several reports describing the role of endoscopes in stapes procedures. This article provides a summary of endoscopic stapes surgery, highlighting the variety of techniques and perceived advantages, as well as audiometric and patient outcomes ( Fig. 1 ).
Surgical technique
An endoscopic stapedotomy or stapedectomy is essentially the same technical procedure as with a microscope, but a few subtle differences do exist. Although some surgeons infiltrate the ear canal with 2% lidocaine in 1:100,000 epinephrine or 0.25% Marcaine in 1:200,000 epinephrine, others place cotton balls soaked in 1:2000 or 1:5000 epinephrine for approximately 5 minutes. Regardless of the technique, hemostasis is paramount to all endoscopic ear surgery, with the surgeon unable to suction during dissection since his or her nondominant hand is typically holding the endoscope. The ear canal skin is then incised approximately 5 to 8 mm lateral to the posterior annulus, allowing elevation of a tympanomeatal flap, and providing access to the middle ear space. With a 0° or 30° endoscope, the incudostapedial joint and oval window niche can almost always be visualized; however, occasionally a variable amount of scutum still needs to be removed to allow instrument access to the region. Once stapes fixation is confirmed, and adequate exposure is obtained, the stapedial tendon is divided. Depending on the surgeon or institution, lasers or microdrills are used to divide the anterior or posterior stapes crus. If one is performing a laser stapedioplasty, the laser is then used to create a small gap in the footplate, posterior to the otosclerotic focus, enabling removal of the otospongiosis involved footplate and crura. In a stapedotomy, a laser, typically CO 2 or potassium titanyl phosphate (KTP), or microdrill, creates a fenestra in the footplate, followed by placement of a piston-type prosthesis. If a stapedectomy is undertaken, tragal perichondrium is typically harvested and used to cover the oval window, followed by placement of the prosthesis between the lenticular process of the incus and the oval window. The tympanomeatal flap is returned to position, and depending on the surgeon, absorbable packing is placed in the ear canal.
Intraoperative issues
Several intraoperative issues have been identified since the first endoscopic stapes procedure was described by Tarabichi in 1999 ( Box 1 ). Although the report described 165 middle ear surgeries that the primary author performed solely with the endoscope over a 5-year period, 13 of those were stapedectomies. Without reporting significant intraoperative details, the author noted that the endoscope reduced the need for curetting the medial bony canal in order to provide exposure to the oval window niche.
Improved visualization
Reduced need for curretting medial bony canal
Decreased chorda tympani manipulation
Difficulty manipulating microdrill with the endoscope
Reduced patient head positioning
One year later, Poe described using an endoscope adjunctively in performing laser stapedioplasties, designing an endoscope with a 200-μm diameter argon laser fiber protruding from the distal tip. The laser was then used to lyse the anterior crus, followed by a row of overlapping burns on the footplate, allowing separation of the footplate between the anterior and middle thirds. No specific intraoperative issues were addressed, and the remainder of the procedure was performed using the microscope.
In 2011, Nogueira and colleagues reported on their experience with endoscopic stapedotomies, addressing perceived differences between microscopic and endoscopic approaches to stapes surgery. Noting that the microscope is limited by direct line of sight during procedures, while endoscopes allow the surgeon to look around corners, the authors assessed 15 patients undergoing endoscopic stapedotomies and reported that the oval window niche, the tympanic segment of the facial nerve, and pyramidal process were all able to be visualized with a 0° endoscope in 8 patients (53.3%). However, when utilizing a 30° endoscope, the same structures were all visualized in 12 patients (80%). In regards to the chorda tympani nerve, they reported that only 3 patients (20%) required manipulation of the nerve to complete the procedure, implying that endoscopes lead to decreased chorda tympani nerve handling compared with microscope cases. Evaluating their ability to perform the procedure, the anterior crus was fractured in all cases with the 30° endoscope, and although there was some difficulty in placing the prosthesis, no intraoperative complications were reported. This highlights an important issue within all endoscopic ear surgery, since although endoscopes provide improved visualization of middle ear structures, commonly used instruments may not be able to access every location visualized.
Despite the limitation, and many surgeons’ concern regarding the need for new instrumentation and monitors to perform endoscopic ear surgery, Nogueira and colleagues purposely worked with endoscopes and microinstruments that most hospitals in which otolaryngologic procedures are performed would have available. And despite use of sinus endoscopes, Nogueira and colleagues emphasized that longer endoscopes do not interfere with the hand movement by remaining in different horizontal planes.
In 2012, Sarkar and colleagues reported their endoscopic stapedotomy results in 30 patients, using 0° and 45° pediatric nasal endoscopes, with a diameter of 2.7 mm, utilizing conventional ear surgery instruments. They found that there was significant difficulty in manipulating the drill and the endoscope within the ear canal; thus they completed all bone removal with a curette. Of interest, prior to performing the surgeries, the authors originally tried using 4 mm and 18 cm long endoscopes on cadavers, but with operational difficulty, they attempted to use 1.9 mm diameter endoscopes. However, limited by poor illumination with the smaller endoscopes, they eventually used pediatric nasal endoscopes to perform the surgeries.
Migirov and Wolf presented their endoscopic stapedotomy technique in 2013, reporting preliminary results on 8 consecutive patients, with at least 6 months of follow-up. All surgeries were performed with a 0° endoscope, although a 30° endoscope was utilized to obtain better visualization of the oval window niche, the anterior crus of the stapes, the tympanic facial nerve segment, and pyramidal eminence in 2 cases due to excessive bony overhang of the medial bony canal. This allowed them to avoid any curettage or drilling of the scutum, as well as avoiding chorda tympani nerve mobilization, while creating the footplate fenestra with a curved 0.5 mm diameter diamond burr. Noting the physical limitations of the scutum, the authors commented on the improved comfort of a right-handed surgeon performing surgery on right ears, with the relative difficultly in left ears in fenestrating the footplate and positioning the prosthesis. With their experience, the authors suggested that the endoscopic approach should be utilized in patients with unfavorable external or middle ear anatomy, those with food-, smell- or taste-related occupations, revision or bilateral stapedotomy candidates, those with already impaired taste sensation, and in those for whom the taste of food contributes to their quality of life.
In 2014, Kojima and colleagues compared 15 patients who underwent endoscopic stapes surgery, with an average follow-up of 8.6 months, against 35 patients and 41 ears who had microscopic stapes surgery and an average follow-up of 27.2 months. Noting that Japanese patients tend to have narrow and curved external auditory canals, in Japan, stapes surgery is routinely performed via a posterior or anterior auricular incision. Thus with unfavorable external ear anatomy for the direct line of sight with the microscope, the authors utilized 2.7 and 4 mm wide, 18 cm long, 0° endoscopes, routinely drilling the bony wall in the posterosuperior part of the canal until the pyramidal eminence and tympanic segment of the facial nerve were visualized. Following prosthesis placement, gelfoam was placed around the footplate fenestra to prevent perilymphatic fistula formation. Assessing the length of the procedure between procedural types, they found no significant difference in time, 54.1 minutes in the endoscopic group versus 53.0 minutes in the microscopic group. The authors noted that when the extent of drilling was adequate for endoscopic surgery, providing visualization of the facial nerve, only the area around the incudostapedial joint could be clearly seen with the microscope.
In 2015, Daneshi and Jahnadideh described their endoscopic stapedotomy experience, highlighting their practice in using no postoperative packing in hopes of minimizing patient annoyance. In regards to their technique, following prosthesis placement, no absorbable materials were placed in the middle ear, and the tympanomeatal flap was repositioned and fixed with tissue adhesive. They performed 19 endoscopic stapedotomies, comparing them with a control group of 15 microscopic stapedotomies; all patients were questioned approximately 6 hours postoperatively about the degree of satisfaction using a visual analog scale. In the endoscopic cohort, utilizing 0° and 30° degree endoscopes, they noted that in 7 (36.8%) cases, no bony removal was required for visualization and access to the oval window niche, while six (31.6%) patients did require minimal curettage, and the chorda tympani nerve was preserved in all cases. Given the reduced need for bony removal, the surgical time was significantly shorter in the endoscopic group as compared with the conventional group, 31.8 minutes as opposed to 54.3 minutes ( P <.05). The authors postulated that reduced patient positioning, as well as less dissection and maneuvers, may partially explain the reduced time in the endoscopic group compared with the microscopic group. However, the authors do not mention how the procedures were timed. The authors posit that endoscopic stapes surgery reduces the need for turning the head in difficult situations, such as those patients with obese short necks, or patients with cervical osteoarthritis.
Marchioni and colleagues recently published their exclusive endoscopic management of stapes malformations in 17 patients, 6 of whom underwent either a stapedotomy or stapedectomy depending on the intraoperative findings. Of the 6 patients, 1 patient had a low intraoperative gusher, controlled with positioning the prosthesis, bovine perichondrium, and fibrin glue, with complete preservation of hearing and closure of the air–bone gap to 5 dB. In 2 other patients, 1 patient had a monopodalic stapes, fused with the footplate, requiring a stapedectomy, while another had a persistent stapedial artery, allowing them to create a stapedotomy anterior to the artery. However, the authors did not comment on the advantages or disadvantages of using the endoscope in their patient population. Nonetheless, the authors believe that the use of endoscopes in challenging anatomy cases, such as malformations and revision cases ( Fig. 2 ), is advantageous, while also recognizing that deep oval window niches are better suited to microscopic stapedotomies given the lack of depth perception during endoscopic procedures.
