Internal Auditory Canal Variability: Anatomic Variation Affects Cisternal Facial Nerve Visualization

2020 ◽  
Vol 19 (3) ◽  
pp. E251-E258 ◽  
Author(s):  
Michael A Cohen ◽  
Hussam Abou-Al-Shaar ◽  
Yair M Gozal ◽  
Michael Karsy ◽  
Gmaan Alzhrani ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Temporal Bone ◽  
Anatomic Variation ◽  
Internal Auditory Canal ◽  
Substantial Effect ◽  
Translabyrinthine Approach ◽  
Surgical Exposure ◽  
Petrous Temporal Bone ◽  
Position And Orientation ◽  
The Individual

Abstract BACKGROUND The internal auditory canal (IAC) is an important landmark during surgery for lesions of the cerebellopontine angle. There is significant variability in the position and orientation of the IAC radiographically, and the authors have noted differences in surgical exposure depending on the individual anatomy of the IAC. OBJECTIVE To test the hypothesis that IAC position and orientation affects the surgical exposure of the IAC and facial nerve, especially when performing the translabyrinthine approach. METHODS The authors retrospectively reviewed magnetic resonance imaging studies of 50 randomly selected patients with pathologically confirmed vestibular schwannomas. Measurements, including the anterior (APD) and posterior (PPD) petrous distances, the anterior (APA) and posterior (PPA) petro-auditory angles, and the internal auditory angle (IAA), were obtained to quantify the position and orientation of the IAC within the petrous temporal bone. RESULTS The results quantitatively demonstrate tremendous variability of the position and orientation of the IAC in the petrous temporal bone. The measurement ranges were APD 10.2 to 26.1 mm, PPD 15.1 to 37.2 mm, APA 104 to 157°, PPA 30 to 96°, and IAA –5 to 40°. CONCLUSION IAC variability can have a substantial effect on the surgical exposure of the IAC and facial and vestibulocochlear nerves. Specifically, a horizontally oriented IAC with a small IAA may have significant impact on visualization of the facial nerve within its cisternal segment with the translabyrinthine approach. The retrosigmoid approach is less affected with IAC variability in position and angle.

Transcranial translabyrinthine approach to vestibular schwannomas

1993 ◽  
Vol 107 (2) ◽  
pp. 111-114 ◽  
Author(s):  
Joseph G. Feghali ◽  
Allen B. Kantrowitz
Keyword(s):  
Facial Nerve ◽  
Temporal Bone ◽  
Semicircular Canal ◽  
Internal Auditory Canal ◽  
Endolymphatic Sac ◽  
Vestibular Schwannomas ◽  
Translabyrinthine Approach ◽  
Vestibular Aqueduct ◽  
Temporal Bones ◽  
Suboccipital Approach

Surgeons who utilize the suboccipital approach for the removal of large vestibular schwannomas, can perform a planned labyrinthectomy from within the intracranial cavity via the suboccipital exposure. This transcranial translabyrinthine approach provides one of the major advantages of the conventional transmastoid translabyrinthine approach, namely, unambiguous identification of the facial nerve as it exits the internal auditory canal, without the need for complete mastoidectomy and labyrinthectomy. The labyrinthectomy is best performed prior to the complete exposure of the internal auditory canal. The approach requires the surgeon to identify the endolymphatic sac intracranially, then drill the temporal bone and follow the vestibular aqueduct to the utricle. The lateral and superior semicircular canal ampullae, the superior vestibular nerve, Bill's bar, and the facial nerve at the lateral end of the internal auditory canal can then be identified. After testing on multiple cadaver temporal bones, this approach was used in patients with large tumours that extended far laterally in the internal auditory canal. The steps in the technique are described in detail.

scholarly journals Unilateral internal auditory canal stenosis with progressive facial weakness

2012 ◽  
Vol 18 (2) ◽  
pp. 179-182
Author(s):  
Sathiya Murali ◽  
Arpana Shekhar ◽  
S Shyam Sudhakar ◽  
Kiran Natarajan ◽  
Mohan Kameswaran
Keyword(s):  
Hearing Loss ◽  
High Resolution ◽  
Facial Nerve ◽  
Temporal Bone ◽  
Internal Auditory Canal ◽  
Facial Weakness ◽  
Profound Hearing Loss ◽  
Canal Stenosis ◽  
Temporal Bone Ct ◽  
Magnetic Resonance Imaging Mri

Internal auditory canal (IAC) stenosis is a rare cause of sensorineural hearing loss. Patient may present with symptoms of progressive facial nerve palsy, hearing loss, tinnitus and giddiness. High resolution temporal bone CT-scan and magnetic resonance imaging (MRI) are the important tools for diagnosis. No specific management has been devised. Here is presentation of a case of unilateral (left) IAC stenosis with profound hearing loss and progressive House Brackmann Grade III-IV facial weakness. The diameter of the IAC was less than 2 mm on high resolution temporal bone computed tomography (HRCT) scan. It was managed by facial nerve decompression by translabyrinthine approach in an attempt to prevent further deterioration of facial palsy. DOI: http://dx.doi.org/10.3329/bjo.v18i2.12014 Bangladesh J Otorhinolaryngol 2012; 18(2): 179-182

The Facial Nerve: How to Find It

1993 ◽  
Vol 72 (10) ◽  
pp. 677-685 ◽  
Author(s):  
Jack L. Pulec
Keyword(s):  
Facial Nerve ◽  
Temporal Bone ◽  
Facial Paralysis ◽  
Anatomic Variation ◽  
Surgical Techniques ◽  
Normal Anatomy ◽  
Bone Surgery ◽  
Temporal Bone Surgery ◽  
Duration Of Surgery

Iatrogenic facial paralysis is one of the most serious and most dreaded complications of temporal bone surgery. The risk of this complication as well as the duration of surgery can be reduced if the otologic surgeon can promptly identify the facial nerve at any stage of an operation. This is especially important in cases of anatomic variation and pathology which obscures or distorts normal anatomy. Twelve different surgical techniques will be described which allow the surgeon to safely expose and identify the facial nerve throughout its course through the temporal bone at any stage of an operation.

Congenital internal auditory canal stenosis

2003 ◽  
Vol 117 (10) ◽  
pp. 784-787 ◽  
Author(s):  
Seung Kuk Baek ◽  
Sung Won Chae ◽  
Hak Hyun Jung
Keyword(s):  
Hearing Loss ◽  
High Resolution ◽  
Facial Nerve ◽  
Ct Scan ◽  
Sensorineural Hearing Loss ◽  
Temporal Bone ◽  
Nerve Palsy ◽  
Facial Nerve Palsy ◽  
Internal Auditory Canal ◽  
Canal Stenosis

Congenital internal auditory canal stenosis is a rare cause of sensorineural hearing loss in children. A retrospective analysis including clinical manifestation and radiological findings was made for seven patients who were diagnosed with congenital internal auditory canal stenosis from 1996 to 2002. Chief presenting symptoms were hearing loss, facial nerve palsy, dizziness, and tinnitus. Hearing loss including deafness was found in five cases, vestibular function loss in four cases, and profound functional loss of facial nerve in two cases. In all cases, the diameter of the internal auditory canal was less than 2 mm on high-resolution temporal bone computed tomography (CT) scan. Two cases revealed bilateral internal auditory canal stenosis, and others were unilaterally involved cases. Congenital internal auditory canal stenosis can be an important cause of sensorineural hearing loss, facial nerve palsy, and vestibular dysfunction. High resolution temporal bone CT scan and magnetic resonance (MR) imaging were important tools for diagnosis.

Pre-operative and per-operative factors conditioning long-term facial nerve function in vestibular schwannoma surgery through translabyrinthine approach

1998 ◽  
Vol 112 (5) ◽  
pp. 441-445 ◽  
Author(s):  
Olivier Deguine ◽  
André Maillard ◽  
Alain Bonafe ◽  
Hassan El Adouli ◽  
Michel Tremoulet ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Vestibular Schwannoma ◽  
Internal Auditory Canal ◽  
Stage Iv ◽  
Nerve Function ◽  
Facial Nerve Function ◽  
Stimulation Threshold ◽  
Translabyrinthine Approach ◽  
Facial Function

AbstractFacial nerve function was evaluated in 103 patients, after vestibular schwannoma removal through the translabyrinthine approach. The mean follow-up was 43 months (minimum six months). Grade I facial function was achieved in 100 per cent of stage I schwannomata compared with 36 per cent of stage IV schwannomata. Grade I or II facial function was found in 78 per cent of homogeneous schwannomata, compared with 48 per cent of heterogeneous schwannomata. Facial function was preserved in 89 per cent of cases, if the angle between the internal auditory canal and the schwannoma was >66°, compared with 54 per cent if the angle was <66°. There was 82 per cent of normal facial function when the nerve appeared normal after tumour removal, compared with 18 per cent when the nerve was traumatized. When the ratio (stimulation threshold at the internal auditory canal/stimulation threshold at brainstem) was <2, postoperative facial function was preserved in 87 per cent of cases, compared with 13 per cent when the ratio was >2.

Diagnosis and treatment of cavernous hemangioma of the internal auditory canal

2016 ◽  
Vol 124 (3) ◽  
pp. 639-646 ◽  
Author(s):  
Wei Dong Zhu ◽  
Qi Huang ◽  
Xi Ye Li ◽  
Hong Sai Chen ◽  
Zhao Yan Wang ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Facial Nerve ◽  
Cavernous Hemangioma ◽  
Cranial Nerves ◽  
Internal Auditory Canal ◽  
Middle Cranial Fossa ◽  
Surgical Removal ◽  
Translabyrinthine Approach ◽  
History Of ◽  
Cranial Fossa

OBJECT Cavernous hemangioma of the internal auditory canal (IAC) is an extremely rare type of tumor, and only 50 cases have been reported in the literature prior to this study. The aim in this study was to describe the symptomatology, radiological features, and surgical outcomes for patients with cavernous hemangioma of the IAC and to discuss the diagnostic criteria and treatment strategy for the disease. METHODS The study included 6 patients with cavernous hemangioma of the IAC. All patients presented with sensorineural hearing loss and tinnitus, and 2 also suffered from vertigo. Five patients reported a history of facial symptoms with hemispasm or palsy: 3 had progressive facial weakness, 1 had a hemispasm, and 1 had a history of recovery from sudden facial paresis. All patients underwent CT and MRI to rule out intracanalicular vestibular schwannomas and facial nerve neuromas. Five patients had their tumors surgically removed, while 1 patient, who did not have facial problems, was followed up with a wait-and-scan approach. RESULTS All patients had a presurgical diagnosis of cavernous hemangioma of the IAC, which was confirmed pathologically in the 5 patients who underwent surgical removal of the tumor. The translabyrinthine approach was used to remove the tumor in 4 patients, while the middle cranial fossa approach was used in the 1 patient who still had functional hearing. Tumors adhered to cranial nerves VII and/or VIII and were difficult to dissect from nerve sheaths during surgeries. Complete hearing loss occurred in all 5 patients. In 3 patients, the facial nerve could not be separated from the tumor, and primary end-to-end anastomosis was performed. Intact facial nerve preservation was achieved in 2 patients. Patients were followed up for at least 1 year after treatment, and MRI showed no evidence of tumor regrowth. All patients experienced some level of recovery in facial nerve function. CONCLUSIONS Cavernous hemangioma of the IAC can be diagnosed preoperatively through analysis of clinical features and neuroimaging. Early surgical intervention may preserve the functional integrity of the facial nerve and provide a better outcome after nerve reconstruction. However, preservation of functional hearing may not be achieved, even with the retrosigmoid or middle cranial fossa approaches. The translabyrinthine approach seems to be the most appropriate approach overall, as the facial nerve can be easily located and reconstructed.

Narrow internal auditory canal syndrome: parasaggital reconstruction

2000 ◽  
Vol 114 (5) ◽  
pp. 392-394 ◽  
Author(s):  
Yang-Sun Cho ◽  
Dong Gyu Na ◽  
Jae Yun Jung ◽  
Sung Hwa Hong
Keyword(s):  
Magnetic Resonance ◽  
High Resolution ◽  
Facial Nerve ◽  
Temporal Bone ◽  
Magnetic Resonance Image ◽  
Internal Auditory Canal ◽  
The Other ◽  
Vestibulocochlear Nerve ◽  
Computed Tomographic ◽  
Canal Syndrome

Narrow internal auditory canal (IAC) syndrome is a malformation of the temporal bone, that is defined as an IAC diameter of only 1–2 mm on high-resolution computed tomographic scans (HRCT). This syndrome is known to be caused by the absence (aplasia or hypoplasia) of the vestibulocochlear nerve. We present a case of unilateral narrow IAC syndrome which was diagnosed by HRCT. The aplasia of the vestibulocochlear nerve was confirmed using parasigittal reconstruction magnetic resonance image (MRI). The IAC was composed of two separate canals, one of which contained a facial nerve and the other was empty with aplasia of the vestibulocochlear nerve.

scholarly journals Facial Palsy and Mastoiditis from Fibrous Dysplasia

2015 ◽  
Vol 30 (2) ◽  
pp. 65-66
Author(s):  
Ian C. Bickle
Keyword(s):  
Facial Nerve ◽  
Fibrous Dysplasia ◽  
Temporal Bone ◽  
External Auditory Canal ◽  
Ground Glass ◽  
Anatomical Location ◽  
Anatomical Site ◽  
Facial Nerve Paralysis ◽  
Nerve Paralysis ◽  
Petrous Temporal Bone

  This young adult man presented to ENT clinic with a complaint of left facial weakness and persistent left retro-auricular pain. High resolution CT of the mastoids was performed following clinical assessment. In this case, there is extensive sclerotic bony expansion with a ground-glass appearance involving the left zygoma, sphenoid and petrous temporal bone. The bony expansion is centred on the medullary bone and has an abrupt zonal transition (Figure 1).  The bone involvement encompasses almost complete bony stenosis of the left external auditory meatus down to 1-2mm with consequential fluid in the external auditory canal and middle ears (Figure 2). The bony expansion involves both the tympanic and mastoid segments of the facial canal which are stenosed.  The ossicular chain remains intact.  The left mastoid air cells are under-pneumatised and completely occupied by fluid. DISCUSSION Fibrous dysplasia (FD) is a benign congenital process that typical manifests itself as a localized defect in osteoblastic differentiation and maturation. Normal bone is replaced with haphazard fibrous tissue and immature woven bone.1 Fibrous dysplasia is predominantly a condition of children and young adults (those less than 30 years of age).  Disease growth usually halts after the third decade of life. FD may be a monostotic or polyostotic in nature and in some cases is part of a syndrome, such as McCune-Albright.2 The zygomatic maxillary complex is the most commonly reported location for fibrous dysplasia.  The temporal bone is a typical site in polyostotic disease, in up to 70%, but less often observed in monoostotic disease.  Disease of the temporal bone most typically results in hearing impairment due to bony stenosis of the external auditory canal. Facial nerve involvement is a less frequent feature, resulting in facial nerve paralysis, due to involvement of the nerve as it exits through the petrous temporal bone.2 The anatomical location of the facial nerve compression is hard to access and treat surgically.3 CT is the imaging investigation of choice giving the most exquisite bony definition.  Typical CT features (as shown in this case) are: A diffuse ground-glass appearance to the affected bone Homogeneously sclerotic bone Well-defined borders between the diseased and unaffected bone (abrupt zone of transition) Bony expansion, with overlying cortical bone intact The CT appearances apply equally to the anatomical site involved, however the combination of imaging appearances can be variable presenting a diagnostic dilemma, which may merit a confirmatory bone biopsy.

scholarly journals Temporal Bone and Cerebellopontine Angle Epidermoid Resulting in Facial Nerve Paralysis: Resection and Facial Nerve Coaptation

2018 ◽  
Vol 80 (S 03) ◽  
pp. S314-S315
Author(s):  
Alexander G. Bien ◽  
Christine S. Kim ◽  
Tyler J. Kenning
Keyword(s):  
Facial Nerve ◽  
Temporal Bone ◽  
Cerebellopontine Angle ◽  
Tumor Resection ◽  
Internal Auditory Canal ◽  
Semicircular Canals ◽  
Facial Nerve Paralysis ◽  
Nerve Paralysis ◽  
Tertiary Center ◽  
End To End

Objectives Demonstrate the utilization of a transcochlear approach for resection of an epidermoid involving the temporal bone and cerebellopontine angle (CPA) with end-to-end facial nerve coaptation. Designs Single case-based operative video. Setting Tertiary center with dedicated skull base team. Participants The patient is a 50-year-old left handed male with a history of a remote left Bell's palsy, left sudden sensorineural hearing loss, and a rapidly progressive facial nerve paralysis. His balance was impaired, and his videonystagmography showed a significant left sided peripheral vestibular weakness. Computed tomography (CT) scan showed an erosive lesion of his left temporal bone involving the cochlea and semicircular canals, and magnetic resonance imaging (MRI) showed a T2 hyperintense lesion with restricted diffusion and no enhancement on postcontrast T1 sequences. Main Outcome Measures Gross total resection of the epidermoid, recovery of facial nerve function, balance improvement. Results The patient underwent resection via a transcochlear approach. The tumor involved the epitympanum and eroded the semicircular canals, vestibule, and basal turn of the cochlea. Gross total tumor resection was attained. The facial nerve was isolated in the mastoid and tympanic segments, traced proximally to the geniculate ganglion, and then into the internal auditory canal (IAC). The nerve was discontinuous in the distal IAC and a reactive neuroma was resected. The facial nerve was mobilized and an end-to-end coaptation was performed in the CPA using a collagen tubule. The 3-month postoperative MRI showed no residual or recurrent disease. His postoperative balance was improved. Partial facial nerve recovery is not expected prior to 9 to 12 months.The link to the video can be found at: https://youtu.be/C6N8qPwBt2Y.

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