| 1. |
- Agrawal, Sumit, et al.
(författare)
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The secondary spiral lamina and its relevance in cochlear implant surgery
- 2018
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Ingår i: Upsala Journal of Medical Sciences. - : TAYLOR & FRANCIS LTD. - 0300-9734 .- 2000-1967. ; 123:1, s. 9-18
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Tidskriftsartikel (refereegranskat)abstract
- Objective: We used synchrotron radiation phase contrast imaging (SR-PCI) to study the 3D microanatomy of the basilar membrane (BM) and its attachment to the spiral ligament (SL) (with a conceivable secondary spiral lamina [SSL] or secondary spiral plate) at the round window membrane (RWM) in the human cochlea. The conception of this complex anatomy may be essential for accomplishing structural preservation at cochlear implant surgery.Material and methods: Sixteen freshly fixed human temporal bones were used to reproduce the BM, SL, primary and secondary osseous spiral laminae (OSL), and RWM using volume-rendering software. Confocal microscopy immunohistochemistry (IHC) was performed to analyze the molecular constituents.Results: SR-PCI reproduced the soft tissues including the RWM, Reissner's membrane (RM), and the BM attachment to the lateral wall (LW) in three dimensions. A variable SR-PCI contrast enhancement was recognized in the caudal part of the SL facing the scala tympani (ST). It seemed to represent a SSL allied to the basilar crest (BC). The SSL extended along the postero-superior margin of the round window (RW) and immunohistochemically expressed type II collagen.Conclusions: Unlike in several mammalian species, the human SSL is restricted to the most basal portion of the cochlea around the RW. It anchors the BM and may influence its hydro-mechanical properties. It could also help to shield the BM from the RW. The microanatomy should be considered at cochlear implant surgery.
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| 2. |
- Atturo, Francesca, et al.
(författare)
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The Human Cochlear Aqueduct and Accessory Canals : a Micro-CT Analysis Using a 3D Reconstruction Paradigm
- 2018
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Ingår i: Otology and Neurotology. - 1531-7129 .- 1537-4505. ; 39:6, s. e429-e435
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Tidskriftsartikel (refereegranskat)abstract
- Objective: We sought to study the anatomic variations of the cochlear aqueduct and its accessory canals in human temporal bones using micro-CT and a 3D reconstruction paradigm. More knowledge about the anatomic variations of these structures, particularly at the basal turn of the cochlea and round window niche, may be important to better preserve residual hearing as well as the neural supply during cochlear implant surgery.Methods: An archival collection of 30 human temporal bones underwent micro-CT and 3D reconstruction. A surface enhancement paradigm was applied. The application displays reconstructed slices as a 3D object with realistic 3D visualization of scanned objects. Virtual sectioning or cropping of the petrous bone presented subsequent areas. Thereby, the bony canals could be followed from inside the basal turn of cochlea and middle ear to the jugular foramen.Results: The cochlear aqueduct was always paralleled by an accessory canal containing the inferior cochlear vein. It ran from the basal turn of the cochlea and exited laterally in the jugular foramen. In 70% of the cases, a secondary accessory canal was observed and it derived mostly from a depression or infundibulum located in the floor of the round window niche. This canal also exited in the jugular foramen. The secondary accessory canal occasionally anastomosed with the primary accessory canal suggesting that it contains a vein that drains middle ear blood to the cranial sinus.Conclusion: Micro-CT with 3D surface reconstruction paradigm offers new possibilities to study the topographic anatomy of minor details in the human inner ear. The technique creates simulated transparent castings of the labyrinth with a coinciding surface view through enhancement of contrast between boundaries. Accessory canals that drain blood from the cochlea, spiral ganglion, and middle ear could be characterized three-dimensionally.
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| 3. |
- Rask-Andersen, Helge, et al.
(författare)
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Special Anatomic Considerations in Otosclerosis Surgery
- 2018
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Ingår i: Otolaryngologic clinics of North America. - : Saunders Elsevier. - 0030-6665 .- 1557-8259. ; 51:2, s. 357-
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Tidskriftsartikel (refereegranskat)abstract
- The anatomy of the vestibular organs together with considerations of the middle and inner ear anatomy relevant to stapes surgery is discussed. An archival collection of macerated and freshly frozen human temporal bones underwent micro computed tomography (CT) with subsequent volume rendering. Three-dimensional (3D) reconstructions and the topographic anatomy of the oval window were considered. Micro-CT and 3D rendering revealed the relationship between the otolith organs and the oval window. Anatomic variations were extensive and included the distance between the footplate and the reconstructed macula margins. A "no-go" zone is suggested for the surgeon to avoid injury during stapes surgery.
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| 4. |
- Schart-Moren, Nadine, et al.
(författare)
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Peri-operative electrically evoked auditory brainstem response assessment of facial nerve/cochlea interaction at cochlear implantation
- 2018
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Ingår i: Cochlear Implants International. - : Informa UK Limited. - 1467-0100 .- 1754-7628. ; 19:6, s. 324-329
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Dehiscence between the cochlear otic capsule and the facial nerve canal is a rare and relatively newly described pathology. In cochlear implantation (CI), this dehiscence may lead to adverse electric facial nerve stimulation (FNS) already at low levels, rendering its use impossible. Here, we describe an assessment technique to foresee this complication.METHODS: Pre- and postoperative computed tomography (CT) scans and intraoperative electrically evoked auditory brainstem response (e-ABR) measurements were analyzed in two patients with cochlear-facial dehiscence (CFD).RESULTS: Because of the relatively low resolution, the confirmation of CFD with a clinical CT was difficult. The e-ABR displayed a large potential with 6 and 7.5 ms latency, respectively, which did not occur otherwise.DISCUSSION: Potential strategies to resolve and manage FNS are described.CONCLUSION: Prediction of FNS by assessing the distance between the labyrinthine portion of the facial nerve and the cochlea is difficult using conventional CT scans. A large evoked late myogenic potential at low stimulation levels during intraoperative e-ABR measurement may foresee FNS at CI activation.
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| 5. |
- Schart-Morén, Nadine
(författare)
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The Human Cochlea and Cochlear Implantation : Morphological Characteristics and Clinical Correlations
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The most common sensory deficit in the world is sensorineural hearing loss. Cochlear implantation (CI) can majorly contribute to restore hearing, not only in patients with severe to profound hearing loss, but also in hearing-impaired patients with residual low-frequency hearing. The overall aims of the present thesis were to study human cochlear anatomy in order to improve structural preservation during CI surgery. An archival collection of temporal bones underwent micro-computer tomography and synchrotron radiation phase-contrast imaging (SR-PCI) with 3D reconstructions, new techniques to digitally image and reproduce the human inner ear. Studying the anatomy of the facial nerve and its interaction with the cochlea revealed that a fusion of the two was found in 1.4 % of the specimens (cochlear-facial dehiscence). This may cause facial nerve excitation after CI. CT-scans and intraoperative electrically auditory brainstem response (e-ABR) measurements were analyzed in patients with cochlear-facial dehiscence. A large evoked late myogenic potential at low stimulation levels during intraoperative e-ABR measurements, can foresee excitation at CI activation. The 3D anatomy of the fundus of the inner acoustic canal was also studied, helping to interpret preoperative imaging of the VIIIth nerve before CI. In a subsequent study, SR-PCI reproduced the soft tissue anatomy at the round window region. Results indicated a high risk for trauma at cochleostomy. For optimal preservation, the round window approach was recommended. In a long-term follow-up the first 21 consecutively operated patients in Uppsala, that underwent hearing preservation CI-surgery, data could be retrieved in 15 patients. Pure tone audiometry was assessed preoperatively and at one, three and >5 years following surgery. Insertion angle, number of electrodes inside the cochlea, user-time of the processor, and stimulation strategies were documented. Results showed that long-term preservation of hearing is possible in most cases. There was a high correlation between insertion depth and preservation of residual hearing. Also, patients with complete hearing loss experienced good performance in speech discrimination and user time.
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| 6. |
- Schart-Moren, Nadine, et al.
(författare)
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Three-Dimensional Analysis of the Fundus of the Human Internal Acoustic Canal
- 2018
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Ingår i: Ear and Hearing. - : Lippincott Williams & Wilkins. - 0196-0202 .- 1538-4667. ; 39:3, s. 563-572
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Documentation of the nerve components in the internal acoustic canal is essential before cochlea implantation surgery. Interpretations may be challenged by wide anatomical variations of the VIIIth nerve and their ramifications. Malformations may further defy proper nerve identification. Design: Using microcomputed tomography, we analyzed the fundus bone channels in an archival collection of 113 macerated human temporal bones and 325 plastic inner molds. Data were subsequently processed by volume-rendering software using a bony tissue algorithm. Three-dimensional reconstructions were made, and through orthogonal sections, the topographic anatomy was established. Results: The technique provided additional information regarding the anatomy of the nerve foramina/channels of the human fundus region, including variations and destinations. Channel anastomosis were found beyond the level of the fundus. A foramen of the transverse crest was identified. Conclusions: Three-dimensional reconstructions and cropping outlined the bone canals and demonstrated the highly variable VIIIth nerve anatomy at the fundus of the human inner acoustic canal. Myriad channel interconnections suggested an intricate system of neural interactive pathways in humans. Particularly striking was the variable anatomy of the saccule nerve channels. The results may assist in the preoperative interpretation of the VIIIth nerve anatomy.
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