Transcanal Endoscopic Ear Surgery to Treat Middle-Ear Cholesteatoma Should be Performed Cautiously
We would like to comment on the report entitled “Transcanal Endoscopic Ear Surgery for Middle Ear Cholesteatoma” by Glikson et al. (1). This constitutes excellent work. Recent developments in endoscopic techniques have facilitated middle-ear surgery, particularly myringoplasty. The authors first systematically evaluated the clinical parameters, outcomes, and complications of transcanal endoscopic ear surgery used to treat middle-ear cholesteatoma. The microscopic approach has the advantages that both hands are free to perform the operation and the operative view is three-dimensional. Endoscopic surgery is one-handed and the operative view is two-dimensional (thus lacking depth). We think that surgical treatment of middle-ear cholesteatoma requires a cautious, two-handed approach. Any new technology requires continuous improvement. However, it is not appropriate to introduce innovations too early. Additionally, the objective of surgery is to completely eliminate disease and prevent recurrence, rather than push surgical boundaries. The surgeon should select a technique with which s/he is comfortable by reference to the location of the lesion. The sample number in the present study was also small; more cases are required.
The authors write, “The two cases of stapes footplate fracture in our series emphasize this fact and the required ‘learning curve’ of the surgeon. Nevertheless, the mean length of surgery in our cohort was similar to classic mastoidectomy operations performed in our department (1).” Although endoscopes differing in angle and diameter may allow “hidden” disease of the middle ear to be viewed, bleeding in the surgical field and bone fragments often contaminate the tip of the endoscope, compromising surgical manipulation. If a microscopic approach is taken, blood may be aspirated using one hand and the surgical instrument manipulated using the other hand. If one hand holds an endoscope, drilling must be performed one-handed, compromising stability. The absence of the third dimension also renders it difficult to discern the hierarchical tissue structure. There are risks that the ossicular chain may be damaged, that ossicular chain reconstruction may be inadequate, and that the cholesteatoma may not be completely excised. Additionally, some authors have reported that the use of transcanal endoscopic ear surgery to treat middle-ear cholesteatoma or reconstruct the ossicular chain is associated with longer procedural times than those of microscopic approaches (2–5).
The authors write, “In two surgeries, cholesteatoma was found to extend posterior to the LSCC into the mastoid cavity and, therefore, conversion to retro-auricular microscopic approach was needed,” and “Involvement by cholesteatoma of the posterior mesotympanum (relative risk [RR] = 1.71, confidence interval [CI] 0.56–5.18) and the oval window niche (RR = 1.6, CI 0.43–5.9) correlated with increased risk for recurrence. (1) ” The posterior mesotympanum and the oval window niche of the middle ear are complex in structure and are shielded by other tissues. It is difficult to completely view these areas even when an endoscope is used. Cholesteatoma of the posterior mesotympanum and oval window niche was not completely removed by drilling and curettage via an endoscopic transcanal approach. However, a microscopic retroauricular approach allowed the cholesteatoma to be completely eliminated. It was necessary to constantly adjust the microscope angle and the patient's head position. We think that endoscopy and microscopy should be combined when it is necessary to remove a cholesteatoma in the posterior mesotympanum and mastoid cavity.