For cochlear implant training and robotic cochlear implant experiments, the design method of scalable scala tympani model was proposed. The mathematical model of the cochlea was used as the central curve of scala tympani channel. Referring to the clinical anatomy data, the contour of the scala tympani cross-section was approximated as an ellipse. The profile was placed along the central curve, and the angle was adjusted to determine the position and orientation of the profile in three dimensions such that the central curve passes through its center. The data was imported into Matlab to generate a three-dimensional mathematical model of scala tympani, which can be expanded by setting different scale factors. The virtual scala tympani model was generated in SolidWorks, and the 2:1 fully transparent scala tympani model were fabricated by 3D printing to replace the specimen for experiment.
Cochlea/surgery* ; Cochlear Implantation ; Cochlear Implants ; Robotics ; Scala Tympani/surgery*

OBJECTIVE: To provide anatomic data for cochlear implantation, and to find the method of locating lamina spiralis (LS) on the surface of promontory. METHOD: Microanatomical study was carried out on 30 sides of human temporal bones by observing and measuring lamina spiralis below promontory, including its location, course and adjacent structures. RESULT: (1) The basal turn of lamina spiralis below promontory can be divided into three segments: the hook segment (1.52 +/- 0.16) mm, the anteroinferior round window segment (3.83 +/- 0.37) mm and the forwarding segment (2.70 +/- 0.36) mm by two hinge points of which one was located at anterior of the junction of superior margin and anterior border of RW, and the other was located at anteroinferior of the round window; (2) The plane of round window anteroinferior segment of LS lay (51.00 +/- 5.97) degrees anteroinferior to horizontal segment of the facial nerve and comparative permanently meet posterior margin of'stapes head. Made posterior margin of stapes head as a fixation point and draw a line on promontory lay (51.00 +/- 45.97) degrees anteroinferior to horizontal segment of the facial nerve. This line can be thought as the projection of anteroinferior round window segment of LS on promontory; (3) The width of scala tympani at cochleostomy site on promontory: width of scala tympani at midpoint of superior margin of round window was (0.36 +/- 0.06) mm; width of scala tympani at midpoint of anterior border of round window was (0.97 +/- 0.14) mm; width of scala tympani at 3 mm point of anteroinferior round window segment was (1.24 +/- 0.21) mm. CONCLUSION (1) The basal turn lamina spiralis below promontory can be divided into three segments (the hook segment, the anteroinferior round window segment and the forwarding segment) by two hinge points; (2) The projection of anteroinferior round window segment of LS and the features exhibited in its course provide reference for locating the basal turn scala tympani and offer reliable anatomical basis for minimal invasive intervention during cochlear implantation.
Adult ; Cochlear Implantation ; methods ; Facial Nerve ; anatomy & histology ; surgery ; Humans ; Round Window, Ear ; anatomy & histology ; surgery ; Scala Tympani ; anatomy & histology ; surgery ; Temporal Bone ; anatomy & histology ; surgery

OBJECTIVETo investigate the related parameters of the temporal bone structure for determining the position of implanting electrode into the scala tympani in cochlear implantation surgery through the facial recess and epitympanum approach.

METHODSIn a surgical simulation experiment, 20 human temporal bones were studied and measured to determine the related parameters of the temporal bone structure.

RESULTSThe distance 5.91∓0.29 mm between the short process of the incus and the round window niche, 2.11∓0.18 mm between the stapes and the round window niche, 6.70∓0.19 mm between the facial nerve in the perpendicular paragraph and the round window niche, 2.22∓0.21 mm from the pyramidal eminence to the round window, and 2.16∓0.14 mm between the stapes and the round window. The minimal distance between the implanting electrode and the vestibular window was 2.12∓0.19 mm. The distance between the cochleariform process and the round window niche was 3.79∓0.17 mm. The position of the cochlear electrode array insertion into the second cochlear turn was 2.25∓0.13 mm under the stapes. The location of the cochlear electrode array insertion into the second cochlear turn was 2.28∓0.20 mm inferior to the pyramidal eminence.

CONCLUSIONThese parameters provide a reference value to determine the different positions of cochlear electrode array insertion into the scale tympani in different patients.

Adult ; Cochlea ; anatomy & histology ; surgery ; Cochlear Implantation ; Cochlear Implants ; Ear, Middle ; anatomy & histology ; surgery ; Female ; Humans ; Male ; Round Window, Ear ; anatomy & histology ; surgery ; Scala Tympani ; anatomy & histology ; surgery