Endoscopic ear surgery (EES) provides several advantages compared with traditional binocular microscopy, including a wide-field view, improved resolution with high magnification, and visual access to hidden corridors of the middle ear. Although binocular microscopic-assisted surgical techniques remain the gold standard for most otologists, EES is slowly emerging as a viable alternative for performing otologic surgery at several centers in the United States and abroad. In this review, we evaluate the current body of literature regarding EES outcomes, summarize our EES outcomes at the Massachusetts Eye and Ear Infirmary, and compare these results with data for microscopic-assisted otologic surgery.
Key points
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Endoscopic ear surgery (EES) is an emerging surgical approach to manage complex middle ear and lateral skull base pathology.
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EES provides equivalent or improved rates of short-term and long-term control of chronic middle ear disease (cholesteatoma) compared with the microscope, while offering decreased morbidity of a minimally invasive approach.
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A growing number of noncholesteatoma otologic procedures are being performed endoscopically, with a wide spectrum of outcomes.
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Well-designed prospective studies on EES are needed to compare outcomes, morbidity, and cost utility compared with microscopic approaches.
Introduction
Endoscopic ear surgery (EES) provides several advantages compared with traditional surgical microscopy. Rigid endoscopy allows for wide-field view of the surgical field, improved resolution with high magnification, and the ability to “look around corners,” enabling direct visualization of the hidden recesses, including the retrotympanum, epitympanum, supratubal recess, protympanum, and hypotympanum.
Endoscopic visualization of the middle ear was first described in the 1960s. Advances in endoscopic instrumentation and video technology allowed Poe and colleagues to describe the use of small-diameter endoscopes to explore the middle ear through a strategically placed myringotomy in the early 1990s. Later that decade, Muaaz Tarabichi described middle ear surgery performed exclusively via endoscopic visualization. Modern high-definition video systems now provide superior image quality that has made endoscopic middle ear surgery a viable alternative to the microscopic techniques in several centers in the United States and abroad ( Fig. 1 ), but there has been slow adoption of EES due to good outcomes with traditional techniques, lack of EES exposure during residency and fellowship training, limited instrumentation, and concerns about one handed surgery and poor depth perception.
A similar reluctance to adopt endoscopic techniques in otolaryngology was seen with the introduction of the endoscope for sinus surgery in the 1980s and 1990s. Opponents expressed similar concerns about the endoscopic compared with microscopic sinus surgery approaches. Nevertheless, the endoscope today represents the gold standard for the management of sinus disease, based on advantages that include improved visualization, decreased blood loss, and better access to pathology while avoiding transfacial and/or sublabial incisions.
A slowly growing body of literature (particularly from centers outside the United States) over the past two decades describes expanding roles for EES. Currently, binocular microscopy remains gold standard. Traditional microscopic approaches provide the benefits of two-handed dissection and depth perception offered by binocular vision (despite the possible need for increased drilling and tissue retraction) and greater proficiency by most surgeons associated with adequate exposure during training. In contrast, proponents of EES suggest several distinct advantages over the microscope, such as improved visualization and access to the hidden recesses of the middle ear, avoidance of a postauricular incision in many cases, and less bony drilling. In ideal form, this minimally invasive approach holds the promise of decreased operative time, less postoperative morbidity, and diminished need for mastoidectomy surgery. In this review, we seek to evaluate the current body of literature regarding EES outcomes, review our EES outcomes at the Massachusetts Eye and Ear Infirmary (MEEI), and compare these results with published data for microscopic surgery.
Appropriate classification of techniques used during otologic surgery is prerequisite to accurately categorizing outcomes. We differentiate between observational EES , which involves endoscopic inspection (otoendoscopy) during an otherwise microscope-only procedure, and operative EES , which ranges from mixed dissection with endoscopic and microscopic techniques, to a transcanal endoscope-only surgical technique. Accordingly, at MEEI we use an EES classification system for documentation purposes that ranges from 0 (microscope-only case) to 3 (transcanal endoscopic ear surgery, TEES; Table 1 ). We define TEES as middle ear surgery performed entirely using the endoscope for visualization, without the use of the operating microscope. Finally, we define residual disease as hidden cholesteatoma that remains and is detected during primary surgery with the endoscope following microscopic resection or identified at a second-look procedure. Recurrence of disease is defined as cholesteatoma formation from a new retraction pocket.
| Class 0 | Class 1 | Class 2 | Class 3 | |
|---|---|---|---|---|
| Intraoperative use of endoscope | None | Inspection only | Mixed dissection | Endoscope only |
| Microscope-only case | Endoscope used to assess disease | Microscope and endoscope used for dissection | No use of microscope | |
| Non-TEES | TEES | |||
The most widely studied application of EES is for management of cholesteatoma. This indication exploits the biggest advantage of the endoscope: the ability to look around corners when using a transcanal approach without depending on line-of-sight surgery needed when using the binocular microscope. We seek to quantify disease control through a comparison of residual/recurrent disease. Additionally, we seek to further highlight other applications of EES, including myringoplasty, tympanoplasty, ossiculoplasty, and relevant hearing outcomes, as well as describe outcomes with other otologic procedures, such as cochlear implantation, stapedectomy, and approaches to the lateral skull base.
In this review, we aim to comprehensively review observational and operational EES outcomes. We further aim to compare EES outcomes with data from microscopic procedures. We hypothesize that EES is a reasonable and less invasive approach compared with microscopic techniques for the management of routine and complex otologic disease.
Introduction
Endoscopic ear surgery (EES) provides several advantages compared with traditional surgical microscopy. Rigid endoscopy allows for wide-field view of the surgical field, improved resolution with high magnification, and the ability to “look around corners,” enabling direct visualization of the hidden recesses, including the retrotympanum, epitympanum, supratubal recess, protympanum, and hypotympanum.
Endoscopic visualization of the middle ear was first described in the 1960s. Advances in endoscopic instrumentation and video technology allowed Poe and colleagues to describe the use of small-diameter endoscopes to explore the middle ear through a strategically placed myringotomy in the early 1990s. Later that decade, Muaaz Tarabichi described middle ear surgery performed exclusively via endoscopic visualization. Modern high-definition video systems now provide superior image quality that has made endoscopic middle ear surgery a viable alternative to the microscopic techniques in several centers in the United States and abroad ( Fig. 1 ), but there has been slow adoption of EES due to good outcomes with traditional techniques, lack of EES exposure during residency and fellowship training, limited instrumentation, and concerns about one handed surgery and poor depth perception.
A similar reluctance to adopt endoscopic techniques in otolaryngology was seen with the introduction of the endoscope for sinus surgery in the 1980s and 1990s. Opponents expressed similar concerns about the endoscopic compared with microscopic sinus surgery approaches. Nevertheless, the endoscope today represents the gold standard for the management of sinus disease, based on advantages that include improved visualization, decreased blood loss, and better access to pathology while avoiding transfacial and/or sublabial incisions.
A slowly growing body of literature (particularly from centers outside the United States) over the past two decades describes expanding roles for EES. Currently, binocular microscopy remains gold standard. Traditional microscopic approaches provide the benefits of two-handed dissection and depth perception offered by binocular vision (despite the possible need for increased drilling and tissue retraction) and greater proficiency by most surgeons associated with adequate exposure during training. In contrast, proponents of EES suggest several distinct advantages over the microscope, such as improved visualization and access to the hidden recesses of the middle ear, avoidance of a postauricular incision in many cases, and less bony drilling. In ideal form, this minimally invasive approach holds the promise of decreased operative time, less postoperative morbidity, and diminished need for mastoidectomy surgery. In this review, we seek to evaluate the current body of literature regarding EES outcomes, review our EES outcomes at the Massachusetts Eye and Ear Infirmary (MEEI), and compare these results with published data for microscopic surgery.
Appropriate classification of techniques used during otologic surgery is prerequisite to accurately categorizing outcomes. We differentiate between observational EES , which involves endoscopic inspection (otoendoscopy) during an otherwise microscope-only procedure, and operative EES , which ranges from mixed dissection with endoscopic and microscopic techniques, to a transcanal endoscope-only surgical technique. Accordingly, at MEEI we use an EES classification system for documentation purposes that ranges from 0 (microscope-only case) to 3 (transcanal endoscopic ear surgery, TEES; Table 1 ). We define TEES as middle ear surgery performed entirely using the endoscope for visualization, without the use of the operating microscope. Finally, we define residual disease as hidden cholesteatoma that remains and is detected during primary surgery with the endoscope following microscopic resection or identified at a second-look procedure. Recurrence of disease is defined as cholesteatoma formation from a new retraction pocket.
| Class 0 | Class 1 | Class 2 | Class 3 | |
|---|---|---|---|---|
| Intraoperative use of endoscope | None | Inspection only | Mixed dissection | Endoscope only |
| Microscope-only case | Endoscope used to assess disease | Microscope and endoscope used for dissection | No use of microscope | |
| Non-TEES | TEES | |||
The most widely studied application of EES is for management of cholesteatoma. This indication exploits the biggest advantage of the endoscope: the ability to look around corners when using a transcanal approach without depending on line-of-sight surgery needed when using the binocular microscope. We seek to quantify disease control through a comparison of residual/recurrent disease. Additionally, we seek to further highlight other applications of EES, including myringoplasty, tympanoplasty, ossiculoplasty, and relevant hearing outcomes, as well as describe outcomes with other otologic procedures, such as cochlear implantation, stapedectomy, and approaches to the lateral skull base.
In this review, we aim to comprehensively review observational and operational EES outcomes. We further aim to compare EES outcomes with data from microscopic procedures. We hypothesize that EES is a reasonable and less invasive approach compared with microscopic techniques for the management of routine and complex otologic disease.
Observational endoscopic ear surgery for cholesteatoma: analysis of outcomes
Observational EES refers to the use of endoscopes for visualization only and as an adjunct to the operating microscope. Table 2 shows outcomes associated with observational endoscopic cholesteatoma resection. Articles range from 10 to 294 patients, and follow-up duration ranges from 3 months to 12 years.
| Authors | Study Design | 1st Procedures | Residual at 1st Procedure | Mean Follow-up (Range) | Cholesteatoma Found During Second Look | Pediatric Patients |
|---|---|---|---|---|---|---|
| Thomassin et al, 1993 | Group A: microscope alone; group B: microscope + endoscopy. Second look with endoscope in all cases | Group A = 36 Group B = 44 | N/A | N/A (12–18 mo) | Group A = 47.7% (n = 21); Group B = 5.5% (n = 2) | Yes (n = 20) |
| Rosenberg et al, 1995 | Endoscope for second look, then microscopic confirmation | 10 | N/A | N/A (8 mo–9 y) | 50.0% (n = 5) | Yes (n = 10) |
| Youssef & Poe, 1997 | Endoscope for second look, then microscopic confirmation | 13 | N/A | N/A (6–12 mo) | 23.1% (n = 3) | Yes (n = 5) |
| Haberkamp & Tanyeri, 1999 | Endoscope for second look, then microscopic confirmation | 15 | N/A | N/A | Endoscope 20.0% (n = 1); microscope 50% (n = 5) | Unknown |
| Good & Isaacson, 1999 | Endoscope as microscope adjunct during 1st procedure; second-look only performed in select patients | 29 | 24.1% (n = 7) | 6.4 mo (12–18 mo) | 18.2% (n = 2 of 11) | Yes (n = 29) |
| Badr-El-Dine, 2002 | Endoscope as microscope adjunct during 1st procedure; second look with endoscope for both observation and dissection | 92 | 22.8% (n = 21) | N/A (9–12 mo) | 8.6% (n = 3 of 35) | Unknown |
| El-Meselaty et al, 2003 | Group A: Endoscope used as microscope adjunct during primary procedure for observation and dissection; group B: primary procedure performed with microscope alone; Second look with endoscope for observation and dissection | Group A = 40 Group B = 42 | Group A = 40.0% (n = 16) | 14.5 mo (12–18 mo) | Group A = 0% (n = 0 of 5); Group B = 42.9% (n = 3 of 7) | Yes |
| Ayache et al, 2008 | Group A: primary procedure performed with microscope alone; group B: endoscope as microscope adjunct during primary procedure for observation and dissection | Group A = 157 Group B = 80 | Group B = 44% (n = 35) | N/A | 37.5% (n = 6 of 16) | Yes |
| Presutti et al, 2008 | Endoscope as microscope adjunct during primary procedure for observation and dissection; second look performed in select patients | 32 | 37.5% (n = 12) | 34 mo (N/A) | 16.7% (2 of 12) | Unknown |
| Badr-El-Dine, 2009 | Endoscope as microscope adjunct during primary procedure for observation and dissection; second look performed in select patients | 294 | 16.7% (n = 49) | 28.2 mo (N/A) | 8.6% (n = 8 of 93) | Unknown |
| Sarcu & Isaacson, 2015 | Endoscopy used for inspection following microscopic resection of disease | 42 | 17% (n = 7) | N/A | 42% in 12 high-risk patients who had second looks | Yes |
| Farahani et al, 2015 | Endoscopy used for inspection following tympanomeatal flap elevation and following microscopic resection of disease | 58 (13 with Cholesteatoma) | 31% (n = 4) | N/A | N/A – no second look performed |
Particularly salient are direct comparisons of endoscopic and microscopic techniques. In one of the largest series, Badr-El-Dine used endoscopic observation following the completion of microscopic canal wall up (CWU) and canal wall down (CWD) procedures; they discovered the prevalence of residual disease missed by the microscope, but detected with the endoscope, was 16.7%. Residual disease was most frequently found in regions where line of sight limitations preclude direct microscopic visualization, while the endoscopic view remains intact: the sinus tympani was the most common site of residual disease in both CWU and CWD groups (36.7%), followed by the facial recess (28.6%), the undersurface of the scutum in the CWU cases (20.4%), and the anterior epitympanic recess (14.3%).
Farahani and colleagues prospectively compared microscopic and endoscopic modalities via a cohort study of 58 patients with chronic otitis media who underwent a microscopic postauricular tympanoplasty with or without mastoidectomy. After a tympanomeatal flap was elevated, the middle ear was evaluated, and the investigators found that the epitympanic, posterior mesotympanic (retrotympanic), and hypotympanic structures were better visualized endoscopically. Moreover, 14 patients with cholesteatoma underwent microscope-only resection, followed by endoscopic reevaluation at the conclusion of the case, which revealed residual disease in 31% (n = 4) of patients. In similar fashion, Sarcu and Isaacson performed otoendoscopy on 42 patients at the conclusion of microscopic resection of cholesteatoma and found 17% with residual disease.
Overall, the summary and comparison data suggest that the enhanced visualization and ability to visualize difficult-to-see regions of the middle ear make observational endoscopic techniques a valuable adjunct to improve outcomes yielded by traditional microscopic techniques.
Operative endoscopic ear surgery/transcanal endoscopic ear surgery for cholesteatoma: analysis of outcomes
Overall rates of recurrent and residual disease following traditional microscopic surgical mastoidectomy procedures are well studied. Large analyses show residual disease in 10% to 40% of ears following CWU tympanomastoidectomy. CWD procedures offer significantly lower risk of residual disease at a cost of greater morbidity: patients undergoing these procedures require lifelong maintenance of the mastoid bowl, while facing persistent issues with thermal sensitivity, caloric stimulation, water precautions, and cosmetic alterations of the meatus.
Performing mixed or fully endoscopic dissection (operative EES) gives the advantages of decreased rates of residual disease associated with observational EES, while potentially avoiding the sequelae of postauricular incision and mastoidectomy. Table 3 lists findings from publications describing EES classified as MEEI class 1 to 3. The number of procedures ranges from 12 to 184, and follow-up ranges from 16 months to 11 years. Importantly, the conversion from TEES to microscopic surgery occurred in 4.3% to 23.8% of procedures, suggesting that most procedures started with a transcanal endoscopic approach can be completed without the need for conversion to the operating microscope. Noted complications include a single case of delayed facial palsy, as well as several cases of postoperative tympanic membrane (TM) perforation, graft lateralization, and decrease in sensorineural hearing. No major complications, such as permanent facial nerve injury or profound sensorineural hearing loss were noted.
| Authors | n∗ | Mean Follow-up (Range) | Second Look/Revisions | Residual Cholesteatoma on Second Look | Conversion to Microscope? | Hearing Outcomes? | Pediatric Patients? | Complications |
|---|---|---|---|---|---|---|---|---|
| Yung, 1994 | 92 | N/A | N/A | N/A | Case started with microscope | N/A | Unknown | N/A |
| Bottrill & Poe, 1995 | 14 | 7 (6–12 mo) | Yes | 3 of 9 (33.3%) | Yes (n = 2 for 1° procedure; n = 2 for 2° procedure) | N/A | Yes | No |
| Tarabichi, 1997 | 36 | 41 mo (N/A) | Yes | n = 4 (unknown %) | No | Yes | Yes | Tympanic membrane defect (n = 9), 15 dB worsened bone conduction at 3000 Hz (n = 1) |
| Tarabichi, 2000 | 69 | 41 mo (N/A) | Yes (n = 6) | Unknown | Yes (4.3%, n = 3) | Yes | Unknown | 15 dB worsened bone conduction at 3000 Hz (n = 1) |
| Yung, 2001 | 231 | N/A (1–12 y) | Yes | 19 of 231 (8.2%) | Case started with microscope | N/A | Yes | N/A |
| Tarabichi, 2004 | 73 | 43 mo (N/A) | Yes | n = 6 (Unknown %) | No | Yes | Yes | N/A |
| Barakate & Bottrill, 2008 | 68 | 16 mo (N/A) | Yes | 14 of 68 (20.6%) | Yes (5.9%, n = 4) | N/A | Yes | N/A |
| Marchioni et al, 2009 | 21 | 23 mo (N/A) | No | N/A | Yes (23.8%, n = 5) | Yes | Unknown | No |
| Migirov et al, 2011 | 30 | N/A (0–1 y) | No | N/A | No | Yes | Yes | Worsening of sensorineural hearing loss (n = 2) |
| Marchioni et al, 2011 | 68 | 18 (6–48) mo | Yes | 3 of 23 (13.0%) | No | No | Unknown | No |
| Marchioni et al, 2013 | 146 | 31.2 mo (N/A) | Yes | 11 of 46 (7.5%) | Yes (17.8%, n = 26) | No | Yes | N/A |
| Hanna et al, 2014 | 184 | 3.2 (1–11) y | Yes | 86 of 184 | Yes–ombined approach | Yes | Yes | N/A |
| Cohen et al, 2016 | 121 (55 chole) | N/A | Yes | 9 of 25 (36%) | Yes–51 TEES, 70 mixed dissection | Yes | Yes | N/A |
| Marchioni et al, 2015 | 31 | 36 (8–88) mo | Yes | 10 of 31 (32.2%) | No–31 TEES compared to 28 CWU control | Yes | Yes | Delayed facial palsy (n = 1), TM lateralization (N = 1) |
| Kobayashi et al, 2015 | 12 | 23.1 (3–51) mo | Yes | 1 of 1 (100%) | No | Yes | Yes | Temporary tympanic membrane defect (n = 2) |
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