scholarly journals Variation of the cochlear anatomy and cochlea duct length: analysis with a new tablet-based software

2021 ◽  
Author(s):  
Jennifer L. Spiegel ◽  
Daniel Polterauer ◽  
John-Martin Hempel ◽  
Martin Canis ◽  
Judith E. Spiro ◽  
...  
Keyword(s):  
Temporal Bone ◽  
Preoperative Assessment ◽  
Hearing Preservation ◽  
Past Century ◽  
Slice Thickness ◽  
Insertion Depth ◽  
Calculation Technique ◽  
Cochlear Malformation ◽  
Available Technology ◽  
Length Analysis

Abstract Purpose In cochlear implantation, thorough preoperative planning together with measurement of the cochlear duct length (CDL) assists in choosing the correct electrode length. For measuring the CDL, different techniques have been introduced in the past century along with the then available technology. A tablet-based software offers an easy and intuitive way to visualize and analyze the anatomy of the temporal bone, its proportions and measure the CDL. Therefore, we investigated the calculation technique of the CDL via a tablet-based software on our own cohort retrospectively. Methods One hundred and eight preoperative computed tomography scans of the temporal bone (slice thickness < 0.7 mm) of already implanted FLEX28™ and FLEXSOFT™ patients were found eligible for analysis with the OTOPLAN software. Measurements were performed by two trained investigators independently. CDL, angular insertion depth (AID), and cochlear coverage were calculated and compared between groups of electrode types, sex, sides, and age. Results Mean CDL was 36.2 ± 1.8 mm with significant differences between sex (female: 35.8 ± 0.3 mm; male: 36.5 ± 0.2 mm; p = 0.037), but none concerning side or age. Differences in mean AID (FLEX28: 525.4 ± 46.4°; FLEXSOFT: 615.4 ± 47.6°), and cochlear coverage (FLEX28: 63.9 ± 5.6%; FLEXSOFT: 75.8 ± 4.3%) were significant (p < 0.001). Conclusion A broad range of CDL was observed with significant larger values in male, but no significant differences concerning side or age. Almost every cochlea was measured longer than 31.0 mm. Preoperative assessment aids in prevention of complications (incomplete insertion, kinking, tipfoldover), attempt of atraumatic insertion, and addressing individual necessities (hearing preservation, cochlear malformation). The preferred AID of 720° (two turns of the cochlea) was never reached, opening the discussion for the requirement of longer CI-electrodes versus a debatable audiological benefit for the patient in his/her everyday life.

The Labyrinthine Portion of the Facial Canal in Patients with Bell's Palsy Investigated by Computed Tomography

1987 ◽  
Vol 28 (1) ◽  
pp. 25-30 ◽  
Author(s):  
K. Wadin ◽  
L. Thomander ◽  
H. Wilbrand
Keyword(s):  
Computed Tomography ◽  
Temporal Bone ◽  
No Value ◽  
Bell’S Palsy ◽  
Ct Images ◽  
Slice Thickness ◽  
Facial Canal ◽  
Bell's Palsy ◽  
Unreliable Method ◽  
Different Parts

The reproducibility of the labyrinthine portion of the facial canal by computed tomography was investigated in 22 patients with Bell's palsy. The CT images were compared with those obtained in 18 temporal bone specimens. Measurements of the diameters of different parts of the facial canal were made on these images and also microscopically in plastic casts of the temporal bone specimens. No marked difference was found between the dimensions of the labyrinthine portion of the facial canal of the involved and healthy temporal bone in the patient, nor did these differ from the dimensions in the specimens. CT of the slender, curved labyrinthine portion was found to be of doubtful value for metric estimation of small differences in width. The anatomic variations of the canal rendered the evaluation more difficult. CT with a slice thickness of 2 mm was of no value for assessment of this part of the canal. Measurement of the diameters of the labyrinthine portion on CT images is an inappropriate and unreliable method for clinical purposes.

scholarly journals Preservation of residual hearing after cochlear implant surgery with slim modiolar electrode

2019 ◽  
Vol 277 (2) ◽  
pp. 367-375 ◽  
Author(s):  
Matti Iso-Mustajärvi ◽  
Sini Sipari ◽  
Heikki Löppönen ◽  
Aarno Dietz
Keyword(s):  
Low Frequency ◽  
Hearing Preservation ◽  
Acoustic Stimulation ◽  
Residual Hearing ◽  
Insertion Depth ◽  
Cochlear Implant Surgery ◽  
Computed Tomography Scans ◽  
Electric Acoustic Stimulation ◽  
Speech Recognition In Noise

Abstract Purpose To evaluate the insertion results and hearing preservation of a novel slim modiolar electrode (SME) in patients with residual hearing. Methods We retrospectively collected the data from the medical files of 17 patients (18 ears) implanted with a SME. All patients had functional low frequency hearing (PTA (0.125–0.5 kHz) ≤ 80 dB HL). The insertion results were re-examined from the postoperative cone-beam computed tomography scans. Postoperative thresholds were obtained at the time of switch-on of the sound processors (mean 43 days) and at latest follow-up (mean 582 days). The speech recognition in noise was measured with the Finnish matrix sentence test preoperatively and at follow-up. Results The mean insertion depth angle (IDA) was 395°. Neither scala dislocations nor tip fold over were detected. There were no total hearing losses. Functional low-frequency hearing was preserved in 15/18 (83%) ears at switch-on and in 14/17 (82%) ears at follow-up. According to HEARRING classification, 55% (10/18) had complete HP at switch-on and 41% (7/17) still at follow-up. Thirteen patients (14 ears) were initially fitted with electric–acoustic stimulation and seven patients (8 ears) continued to use it after follow-up. Conclusions The preliminary hearing preservation results with the SME were more favorable than reported for other perimodiolar electrodes. The results show that the array may also be feasible for electro-acoustic stimulation; it is beneficial in that it provides adequate cochlear coverage for pure electrical stimulation in the event of postoperative or progressive hearing loss.

scholarly journals Delayed loss of hearing after hearing preservation cochlear implantation: Human temporal bone pathology and implications for etiology

2016 ◽  
Vol 333 ◽  
pp. 225-234 ◽  
Author(s):  
Alicia M. Quesnel ◽  
Hideko Heidi Nakajima ◽  
John J. Rosowski ◽  
Marlan R. Hansen ◽  
Bruce J. Gantz ◽  
...  
Keyword(s):  
Temporal Bone ◽  
Cochlear Implantation ◽  
Hearing Preservation ◽  
Bone Pathology ◽  
Human Temporal Bone ◽  
Loss Of Hearing

scholarly journals COMPUTER AIDED THREE-DIMENSIONAL RECONSTRUCTION AND MODELING OF MIDDLE EAR BIOMECHANICS BY HIGH-RESOLUTION COMPUTED TOMOGRAPHY AND FINITE ELEMENT ANALYSIS

2006 ◽  
Vol 18 (05) ◽  
pp. 214-221 ◽  
Author(s):  
CHIA-FONE LEE ◽  
PEIR-RONG CHEN ◽  
WEN-JENG LEE ◽  
JYH-HORNG CHEN ◽  
TIEN-CHEN LIU
Keyword(s):  
Computed Tomography ◽  
Finite Element Analysis ◽  
Finite Element ◽  
High Resolution ◽  
Temporal Bone ◽  
Middle Ear ◽  
Histological Section ◽  
Slice Thickness ◽  
High Resolution Computed Tomography ◽  
Element Analysis

In order to present a systematic and practical approach that uses high-resolution computed tomography (HRCT) to derive models of the middle ear for finite element analysis (FEA). This prospective study included 31 subjects with normal hearing and no previous otological disorders. Temporal bone images obtained from 15 right ears and 16 left ears were used for evaluation and reconstruction. High-resolution computed tomography of temporal bone was performed using simultaneous acquisition of 16 sections with a collimated slice thickness of 0.625 mm. All images were transferred to an Amira visualization system for 3D reconstruction. The created 3-D model was translated into two commercial modeling packages, Patran and ANSYS, for finite element analysis. The characteristic dimensions of the model were measured and compared with previous published histological section data. This result confirms that the geometric model created by the proposed method is accurate except the tympanic membrane is thicker than that of histological section method. No obvious difference in the geometrical dimension between right and left ossicles was found (p > 0.05). The 3D model created by finite element method and predicted umbo and stapes displacements are close to the bounds of the experimental curves of Nishihara's, Huber's, and Gan's data across the frequency range of 100-8000 Hz. The model includes a description of the geometry of the middle ear components, and dynamic equations of vibration. The proposed method is quick, practical, low cost and most importantly, non-invasive as compared with histological section methods.

Hearing Preservation after Lateral Temporal Bone Resection for Early-Stage External Auditory Canal Carcinoma

2014 ◽  
Vol 19 (6) ◽  
pp. 351-357 ◽  
Author(s):  
Shinya Morita ◽  
Yuji Nakamaru ◽  
Akihiro Homma ◽  
Tomohiro Sakashita ◽  
Masayori Masuya ◽  
...  
Keyword(s):  
Temporal Bone ◽  
External Auditory Canal ◽  
Early Stage ◽  
Hearing Preservation ◽  
Bone Resection ◽  
Temporal Bone Resection ◽  
Lateral Temporal Bone Resection

scholarly journals Triggered kV Imaging During Spine SBRT for Intrafraction Motion Management

2021 ◽  
Vol 20 ◽  
pp. 153303382110630
Author(s):  
Jihye Koo ◽  
Louis Nardella ◽  
Michael Degnan ◽  
Jacqueline Andreozzi ◽  
Hsiang-hsuan M. Yu ◽  
...  
Keyword(s):  
Slice Thickness ◽  
Clinical Implementation ◽  
Motion Management ◽  
Treatment Delivery ◽  
Image Guided Radiotherapy ◽  
Intrafraction Motion ◽  
Non Invasive ◽  
Spinous Processes ◽  
Structure Accuracy ◽  
Available Technology

Purpose: To monitor intrafraction motion during spine stereotactic body radiotherapy(SBRT) treatment delivery with readily available technology, we implemented triggered kV imaging using the on-board imager(OBI) of a modern medical linear accelerator with an advanced imaging package. Methods: Triggered kV imaging for intrafraction motion management was tested with an anthropomorphic phantom and simulated spine SBRT treatments to the thoracic and lumbar spine. The vertebral bodies and spinous processes were contoured as the image guided radiotherapy(IGRT) structures specific to this technique. Upon each triggered kV image acquisition, 2D projections of the IGRT structures were automatically calculated and updated at arbitrary angles for display on the kV images. Various shifts/rotations were introduced in x, y, z, pitch, and yaw. Gantry-angle-based triggering was set to acquire kV images every 45°. A group of physicists/physicians(n = 10) participated in a survey to evaluate clinical efficiency and accuracy of clinical decisions on images containing various phantom shifts. This method was implemented clinically for treatment of 42 patients(94 fractions) with 15 second time-based triggering. Result: Phantom images revealed that IGRT structure accuracy and therefore utility of projected contours during triggered imaging improved with smaller CT slice thickness. Contouring vertebra superior and inferior to the treatment site was necessary to detect clinically relevant phantom rotation. From the survey, detectability was proportional to the shift size in all shift directions and inversely related to the CT slice thickness. Clinical implementation helped evaluate robustness of patient immobilization. Based on visual inspection of projected IGRT contours on planar kV images, appreciable intrafraction motion was detected in eleven fractions(11.7%). Discussion: Feasibility of triggered imaging for spine SBRT intrafraction motion management has been demonstrated in phantom experiments and implementation for patient treatments. This technique allows efficient, non-invasive monitoring of patient position using the OBI and patient anatomy as a direct visual guide.

Application Accuracy of Computed Tomography-based, Image-guided Navigation of Temporal Bone

2008 ◽  
Vol 63 (suppl_4) ◽  
pp. ONS326-ONS333 ◽  
Author(s):  
Promod Pillai ◽  
Steffen Sammet ◽  
Mario Ammirati
Keyword(s):  
Computed Tomography ◽  
High Resolution ◽  
Temporal Bone ◽  
Retrosigmoid Approach ◽  
Surgical Approaches ◽  
Slice Thickness ◽  
Image Guided ◽  
Temporal Bone Surgery ◽  
Navigation Accuracy ◽  
Reference Markers

Abstract Objective: Although frameless stereotactic techniques have become indispensable in neurosurgery, their technical complexity requires careful definition and evaluation. Navigation is of particular concern when it is applied to approach a complex, tight surgical area like the temporal bone, where every millimeter is important. Theoretically, the temporal bone is an ideal location in which to use image-guided navigation because its bony construct precludes pre- and intraoperative shift. In this context, the feasibility of using a navigational system is determined by the system’s accuracy and by the spatial characteristics of the targets. Literature addressing the accuracy of image guidance techniques in temporal bone surgery is relatively sparse. Accuracy of these systems within the temporal bone is still under investigation. We investigated the application accuracy of computed tomography-based, frameless, image-guided navigation to identify various bony structures in the temporal bone via a retrosigmoid approach. Methods: In a total of 10 operations, we performed a retrosigmoid approach simulating operative conditions on either side of 5 whole, fresh cadaveric heads. Six titanium microscrews were implanted around the planned craniotomy site as permanent bone reference markers before the surgical procedure. High-resolution computed tomographic scans were obtained (slice thickness, 0.6-mm, contiguous non-overlapping slices; gantry setting, 0 degrees; scan window diameter, 225 mm; pixel size, &gt;0.44 × 0.44). We used a Stryker navigation system (Stryker Instruments, Kalamazoo, MI) for intraoperative navigation. External and internal targets were selected for calculation of navigation accuracy. Results: The system calculated target registration error to be 0.48 ± 0.21 mm, and the global accuracies (navigation accuracies) were calculated using external over-the-skull and internal targets within the temporal bone. Overall navigation accuracy was 0.91 ± 0.28 mm; for reaching internal targets within temporal bone, accuracy was 0.94 ± 0.22 mm; and for external targets, accuracy was 0.83 ± 0.11 mm. Ninety-five percent of targets could be reached within 1.4 mm of their actual position. Conclusion: Using high-resolution computed tomography and bone-implanted reference markers, frameless navigation can be as accurate as frame-based stereotaxy in providing a guide to maximize safe surgical approaches to the temporal bone. Although error-free navigation is not possible with the submillimetric accuracy required by direct anatomic contouring of tiny structures within temporal bone, it still provides a road map to maximize safe surgical exposure.

Giant cell reparative granuloma of the temporal bone successfully resected with preservation of hearing

2013 ◽  
Vol 127 (7) ◽  
pp. 716-720 ◽  
Author(s):  
Y Takata ◽  
H Hidaka ◽  
K Ishida ◽  
T Kobayashi
Keyword(s):  
Magnetic Resonance Imaging ◽  
Computed Tomography ◽  
Magnetic Resonance ◽  
Giant Cell ◽  
Temporal Bone ◽  
Hearing Preservation ◽  
Resonance Imaging ◽  
Giant Cell Reparative Granuloma ◽  
Total Resection ◽  
History Of

AbstractObjective:To describe a case of giant cell reparative granuloma of the temporal bone which extended into the middle-ear cavity, and which was successfully treated surgically via a transmastoid approach, with hearing preservation.Case:A 37-year-old man presented with a one-year history of right-sided hearing loss, complicated by a three-month history of otalgia and a sensation of aural fullness. Computed tomography and magnetic resonance imaging demonstrated an osteolytic tumour lesion in the right temporal bone. The diagnosis was confirmed by biopsy from the mastoid lesion.Investigation and intervention:Pure-tone audiometry, computed tomography and magnetic resonance imaging were conducted, followed by total resection.Result:The giant cell reparative granuloma of the temporal bone was completely resected, with preservation of hearing.Conclusion:Although this patient's giant cell reparative granuloma of the temporal bone extended into the middle-ear cavity, total resection was achieved, with preservation of hearing. To the best of our knowledge, hearing preservation following resection of giant cell reparative granuloma of the temporal bone has not previously been reported.

scholarly journals Insertion depth impacts speech perception and hearing preservation for lateral wall electrodes

2017 ◽  
Vol 127 (10) ◽  
pp. 2352-2357 ◽  
Author(s):  
Brendan P. O'Connell ◽  
Jacob B. Hunter ◽  
David S. Haynes ◽  
Jourdan T. Holder ◽  
Matt M. Dedmon ◽  
...  
Keyword(s):  
Speech Perception ◽  
Lateral Wall ◽  
Hearing Preservation ◽  
Insertion Depth
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