The round window region and contiguous areas: endoscopic anatomy and surgical implications

Abstract

The round window region is a critical area of the middle ear; the aim of this paper is to describe its anatomy from an endoscopic perspective, emphasizing some structures, the knowledge of which could have important implications during surgery, as well as to evaluate what involvement cholesteatoma may have with these structures. Retrospective review of video recordings of endoscopic ear surgeries and retrospective database review were conducted in Tertiary university referral center. Videos from endoscopic middle ear procedures carried out between June 2010 and September 2012 and stored in a shared database were reviewed retrospectively. Surgeries in which an endoscopic magnification of the round window region and the inferior retrotympanum area was performed intraoperatively were included in the study. Involvement by cholesteatoma of those regions was also documented based on information obtained from the surgical database. Conformation of the tegmen of the round window niche may influence the surgical view of round window membrane. A structure connecting the round window area to the petrous apex, named the subcochlear canaliculus, is described. Cholesteatoma can invade the round window areas in some patients. Endoscopic approaches can guarantee a very detailed view and allow the exploration of the round window region. Exact anatomical knowledge of this region can have important advantages during surgery, since some pathology can invade inside cavities or tunnels otherwise not seen by instrumentation that produces a straight-line view (e.g. microscope).

Endoscopic transcanal corridors to the lateral skull base: Initial experiences

“…Three main structures represent the limits and, at the same time, the landmarks for this approach: the carotid artery anteriorly, the internal jugular vein posteriorly, and the cochlea inferiorly. The subcochlear canaliculus, a small tunnel that connects the round window chamber region to the petrous apex, can be followed from a lateral to a medial direction, indicating the correct route …”

“…, Fig. B) . The jugular bulb was thus identified below the finiculus bone in the floor of the hypotympanum, and identification of the vertical tract of the carotid artery was performed by drilling the protympanic cells just below the eustachian tube orifice.…”

Endoscopic vs Microscopic Approach in Stapes Surgery: Advantages in the Middle Ear Structures Visualization and Trainee's Point of View

“…According to these data, a "total" identification of the stapes footplate and the oval window was 16 J Int Adv Otol 2017; 13(1): [14][15][16][17][18][19][20] Significant information marked in bold. p value has been calculated between "total" identification and overall "partial" and "no" identification of the two different surgical approaches.…”

“…With endoscopes, the line of sight can be moved closer to the surgical field, allowing more complete surveillance. In addition, endoscopes allow visualization around structures, which is not possible with a conventional microscope and is greatly augmented with angled endoscopes [6,[13][14][15][16] . Accordingly, an increasing number of ear-surgeons nowadays considers otosclerosis to be a suitable disease for endoscopic stapes surgery due to the fact that the endoscopic approach offers excellent visualization of middle ear structures and recesses, mainly the oval window niche, stapes anterior crus, and its suprastructure [5,6,[17][18][19] .…”

Using endoscopy to locate the round window membrane during cochlear implantation: Our experience with 25 patients

“…However, it can be difficult to access the round window membrane in certain patients, especially in paediatric patients or patients with inner ear malformations . Recently, it has been demonstrated that endoscopy enables excellent visualisation and exploration of the round window niche in ear surgery . In this study, we report our experiences in a prospective cohort of 25 patients (27 ears) exploring the use of endoscopy in locating the round window membrane during cochlear implantation.…”