Enhanced Retrosigmoid Exposure with Posterior Semicircular Canal Resection

1996 ◽  
Vol 115 (1) ◽  
pp. 46-48 ◽  
Author(s):  
Ltc Moises Arriaga ◽  
Maj Michael Gorum
Keyword(s):  
Semicircular Canal ◽  
Cerebellopontine Angle ◽  
Internal Auditory Canal ◽  
Hearing Preservation ◽  
Middle Fossa ◽  
Posterior Semicircular Canal ◽  
Acoustic Neuromas

A subset of patients with acoustic neuromas and useful hearing have tumors that are inadequately approached by both middle fossa and retrosigmoid techniques. The enhanced retrosigmoid technique combines the hearing preservation of posterior semicircular canal ablation to achieve lateral internal auditory canal exposure with the ample cerebellopontine angle exposure of the standard retrosigmoid technique.

Preservation of hearing in patients undergoing excision of acoustic neuromas and other cerebellopontine angle tumors

1985 ◽  
Vol 63 (2) ◽  
pp. 168-174 ◽  
Author(s):  
Charles H. Tator ◽  
Julian M. Nedzelski
Keyword(s):  
Tumor Size ◽  
Cerebellopontine Angle ◽  
Internal Auditory Canal ◽  
Hearing Preservation ◽  
Cochlear Nerve ◽  
Consecutive Series ◽  
Speech Discrimination ◽  
Content Type ◽  
Acoustic Neuromas ◽  
Fine Print

✓ Microsurgical techniques have made it possible to identify and preserve the cochlear nerve from its origin at the brain stem and along its course through the internal auditory canal in patients undergoing removal of small or medium-sized acoustic neuromas or other cerebellopontine angle (CPA) tumors. In a consecutive series of 100 patients with such tumors operated on between 1975 and 1981, an attempt was made to preserve the cochlear nerve in 23. The decision to attempt to preserve hearing was based on tumor size and the degree of associated hearing loss. In cases of unilateral acoustic neuroma, the criteria for attempted preservation of hearing were tumor size (2.5 cm or less), speech reception threshold (50 dB or less), and speech discrimination score (60% or greater). In patients with bilateral acoustic neuromas or tumors of other types, the size and hearing criteria were significantly broadened. All patients were operated on through a suboccipital approach. Hearing was preserved postoperatively in six (31.6%) of the 19 patients with unilateral acoustic neuromas, although the cochlear nerve was preserved in 16. Of the six patients with postoperative hearing, three retained excellent hearing, and the other three had only sound awareness and poor discrimination. Hearing was preserved in three cases with other CPA tumors, including an epidermoid cyst and small petrous meningiomas in the internal auditory canal. Of the two cases with bilateral tumors, hearing was preserved in one. Of the 23 patients in whom hearing preservation was attempted, nine (39.1%) had some postoperative hearing, which in six was equal to or better than the preoperative level. Thus, it is worthwhile to attempt hearing preservation in selected patients with CPA tumors.

The Singular Canal: A Valuable Landmark in Surgery of the Internal Auditory Canal

1988 ◽  
Vol 98 (2) ◽  
pp. 138-143 ◽  
Author(s):  
Herbert Silverstein ◽  
Horace Norrell ◽  
Eric Smouha ◽  
Thomas Haberkamp
Keyword(s):  
Hearing Loss ◽  
High Resolution ◽  
Sensorineural Hearing Loss ◽  
Semicircular Canal ◽  
Internal Auditory Canal ◽  
Retrosigmoid Approach ◽  
Posterior Semicircular Canal ◽  
Vestibular Neurectomy ◽  
Acoustic Neuromas ◽  
Acoustic Neuroma Surgery

The singular canal transmits the posterior ampullary nerve between the inferior part of the internal auditory canal (IAC) and ampulla of the posterior semicircular canal. The anatomy of the singular canal was studied in temporal bone dissections, in surgical dissections, and in high-resolution computerized tomography scans. Measurements were taken for distances between the origin of the singular canal in the IAC, the porus acousticus, the vestibule, and posterior canal ampulla. The location and importance of the singular canal are demonstrated for retrosigmoid-IAC vestibular neurectomy, retrosigmoid acoustic neuroma surgery, and transcochlear cochleovestibular neurectomy. The main purpose for the use of the retrosigmoid approach to the internal auditory canal during vestibular neurectomy and excision of acoustic neuromas is preservation of hearing. A major concern when the contents of the internal auditory canal are exposed through this approach is fenestration of the labyrinth, which results in sensorineural hearing loss. In the retrosigmoid approach, the singular canal has been found to be a vital landmark in prevention of fenestration during surgery of the internal auditory canal.

scholarly journals Risk of Posterior Semicircular Canal Trauma when using a Retrosigmoid approach for Acoustic Neuroma Surgery and role of Endoscopy: An Imaging Study

2018 ◽  
Vol 97 (1-2) ◽  
pp. 24-30 ◽  
Author(s):  
Ali Kouhi ◽  
Varasteh Vakili Zarch ◽  
Ali Pouyan
Keyword(s):  
Temporal Bone ◽  
Semicircular Canal ◽  
Internal Auditory Canal ◽  
Imaging Study ◽  
Hearing Preservation ◽  
Neoplastic Disease ◽  
Posterior Semicircular Canal ◽  
Temporal Bone Ct ◽  
Temporal Bones

The rate of hearing preservation after vestibular schwannoma surgery is variable and is not as high as expected, possibly due to injuries to the posterior semicircular canal while exposing the tumor. The aim of this study was to estimate the risk of posterior semicircular canal injuries using temporal bone computed tomography (CT) scan findings. Temporal bone CT scans of 30 patients selected between 2013 and 2015 were studied. The median age of the patients was 40 years. Two planes were studied: (1) the axial plane that shows the common crus of the posterior semicircular canal and (2) the coronal plane that shows the two crura of the posterior semicircular canal. Five lines were drawn and four angles and three distances were measured. In this study, we divided the patients into three groups consisting of 10 patients each: (1) patients with no evidence of inflammatory or neoplastic disease, (2) those with chronic ear disease, and (3) those with vestibular schwannomas. The portion of the internal auditory canal that was exposed by drilling while preserving the posterior semicircular canal was 53 to 64% and 61 ± 9% in whole temporal bones in the three groups. The mean angle of vision with an endoscope was less than 105° in 56% of cases, which means even with a 30° endoscope, the fundus could not be visualized. Therefore, according to our data, it seemed impossible to expose the whole length of the internal auditory canal from the porus to the fundus without causing injury to the posterior semicircular canal. However, the use of endoscopes may help to prevent injury.

scholarly journals Risk of Posterior Semicircular Canal Trauma When Using a Retrosigmoid Approach for Acoustic Neuroma Surgery and Role of Endoscopy: An Imaging Study

2018 ◽  
Vol 97 (1-2) ◽  
pp. 24-30
Author(s):  
Ali Kouhi ◽  
Varasteh Vakili Zarch ◽  
Ali Pouyan
Keyword(s):  
Temporal Bone ◽  
Semicircular Canal ◽  
Internal Auditory Canal ◽  
Imaging Study ◽  
Hearing Preservation ◽  
Neoplastic Disease ◽  
Posterior Semicircular Canal ◽  
Temporal Bone Ct ◽  
Temporal Bones

The rate of hearing preservation after vestibular schwannoma surgery is variable and is not as high as expected, possibly due to injuries to the posterior semicircular canal while exposing the tumor. The aim of this study was to estimate the risk of posterior semicircular canal injuries using temporal bone computed tomography (CT) scan findings. Temporal bone CT scans of 30 patients selected between 2013 and 2015 were studied. The median age of the patients was 40 years. Two planes were studied: (1) the axial plane that shows the common crus of the posterior semicircular canal and (2) the coronal plane that shows the two crura of the posterior semicircular canal. Five lines were drawn and four angles and three distances were measured. In this study, we divided the patients into three groups consisting of 10 patients each: (1) patients with no evidence of inflammatory or neoplastic disease, (2) those with chronic ear disease, and (3) those with vestibular schwannomas. The portion of the internal auditory canal that was exposed by drilling while preserving the posterior semicircular canal was 53 to 64% and 61 ± 9% in whole temporal bones in the three groups. The mean angle of vision with an endoscope was less than 105° in 56% of cases, which means even with a 30° endoscope, the fundus could not be visualized. Therefore, according to our data, it seemed impossible to expose the whole length of the internal auditory canal from the porus to the fundus without causing injury to the posterior semicircular canal. However, the use of endoscopes may help to prevent injury.

scholarly journals 3D Real IR MR Findings in Acoustic Neuromas: Altered Perilymph Metabolism

2021 ◽  
pp. 014556132110471
Author(s):  
Suming Shi ◽  
Ping Guo ◽  
Wenquan Li ◽  
Wuqing Wang
Keyword(s):  
Inner Ear ◽  
Acoustic Neuroma ◽  
Intravenous Administration ◽  
Semicircular Canal ◽  
Signal Intensity ◽  
Cerebellopontine Angle ◽  
Endolymphatic Hydrops ◽  
Internal Auditory Canal ◽  
Control Side ◽  
Acoustic Neuromas

Objectives This study aimed to investigate the perilymph metabolism by analyzing the 3D real IR MR findings in acoustic neuroma (AN) after intravenous administration of gadolinium (Gd). Methods Eleven patients (6 men and 5 women) diagnosed with AN were included, and 3D real IR MRI was performed 4 hours after intravenous Gd injection. The signal intensity and details of inner ear, tumor, and internal auditory canal (IAC) by MRI were analyzed. Results Four patients had tumors confined to the IAC, and 5 had tumors that extended to the cerebellopontine angle cistern. The signal intensity of the cochlea, vestibule, and IAC fundus was conspicuously enhanced in 3D real IR images than the control side. One patient had a tumor in the cochlea, in which the signal intensity of the semicircular canal and vestibule was increased. One patient had an intravestibular tumor in which the signal intensity of the semicircular canal was increased and the cochlea had endolymphatic hydrops in the affected ear. Conclusions The synchronously increased signal intensity in the inner ear and IAC may indicate that IAC may serve as a channel for removal of the perilymph in the inner ear; the blockage by the tumor may have changed the hydrodynamics of the perilymph to cause a longer retention of Gd in the inner ear.

Translabyrinthine Approach for Acoustic Neuroma

Neurosurgery ◽  
2004 ◽  
Vol 54 (2) ◽  
pp. 391-396 ◽  
Author(s):  
John Diaz Day ◽  
Douglas A. Chen ◽  
Moises Arriaga
Keyword(s):  
Surgical Treatment ◽  
Acoustic Neuroma ◽  
Cerebellopontine Angle ◽  
Hearing Preservation ◽  
Retrosigmoid Approach ◽  
The Past ◽  
Translabyrinthine Approach ◽  
Acoustic Neuromas

Abstract THE TRANSLABYRINTHINE APPROACH has been popularized during the past 30 years for the surgical treatment of acoustic neuromas. It serves as an alternative to the retrosigmoid approach in patients when hearing preservation is not a primary consideration. Patients with a tumor of any size may be treated by the translabyrinthine approach. The corridor of access to the cerebellopontine angle is shifted anteriorly in contrast to the retrosigmoid approach, resulting in minimized retraction of the cerebellum. Successful use of the approach relies on a number of technical nuances that are outlined in this article.

scholarly journals Resection of a Dumbbell-Shaped Facial Nerve Schwannoma With Preservation of Facial Nerve Function Through the Extended Middle Fossa Approach: 2-Dimensional Operative Video

2021 ◽  
Author(s):  
Kaith K Almefty ◽  
Wenya Linda Bi ◽  
Walid Ibn Essayed ◽  
Ossama Al-Mefty
Keyword(s):  
Facial Nerve ◽  
Cerebellopontine Angle ◽  
Internal Auditory Canal ◽  
Growth Patterns ◽  
Geniculate Ganglion ◽  
Nerve Function ◽  
Middle Fossa ◽  
Facial Nerve Function ◽  
Large Tumor ◽  
Middle Fossa Approach

Abstract Facial nerve schwannomas are rare and can arise from any segment along the course of the facial nerve.1 Their location and growth patterns present as distinct groups that warrant specific surgical management and approaches.2 The management challenge arises when the facial nerve maintains good function (House-Brackmann grade I-II).3 Hence, a prime goal of management is to maintain good facial animation. In large tumors, however, resection with facial nerve function preservation should be sought and is achievable.4,5  While tumors originating from the geniculate ganglion grow extradural on the floor of the middle fossa, they may extend via an isthmus through the internal auditory canal to the cerebellopontine angle forming a dumbbell-shaped tumor. Despite the large size, they may present with good facial nerve function. These tumors may be resected through an extended middle fossa approach with preservation of facial and vestibulocochlear nerve function.  The patient is a 62-yr-old man who presented with mixed sensorineural and conductive hearing loss and normal facial nerve function. Magnetic resonance imaging (MRI) revealed a large tumor involving the middle fossa, internal auditory meatus, and cerebellopontine angle.  The tumor was resected through an extended middle fossa approach with a zygomatic osteotomy and anterior petrosectomy.6 A small residual was left at the geniculate ganglion to preserve facial function. The patient did well with hearing preservation and intact facial nerve function. He consented to the procedure and publication of images.  Image at 1:30 © Ossama Al-Mefty, used with permission. Images at 2:03 reprinted from Kadri and Al-Mefty,6 with permission from JNSPG.

Asymmetry of the Internal Auditory Canals without Acoustic Neuroma

1978 ◽  
Vol 87 (6) ◽  
pp. 815-820 ◽  
Author(s):  
Kenneth D. Dolan ◽  
Richard W. Babin ◽  
Charles G. Jacoby
Keyword(s):  
Posterior Fossa ◽  
Acoustic Neuroma ◽  
Cerebellopontine Angle ◽  
Clinical Presentation ◽  
Internal Auditory Canal ◽  
Internal Auditory Meatus ◽  
Radiographic Appearance ◽  
The Past ◽  
Acoustic Neuromas ◽  
Normal Architecture

During the past five years, nine patients with “significant” unilateral enlargement of one internal auditory canal by polytomography were subsequently found to have freely filling canals on contrast posterior fossa myelography. The radiographic appearance of the enlarged canals varied greatly and included all the various configurations usually suggestive of acoustic neuroma. Likewise, the clinical presentation varied greatly from asymptomatic to highly suggestive of cerebellopontine angle tumor. This series underscores the essential nature of posterior fossa studies in the evaluation of potential acoustic neuromas and the variability of the normal architecture of the internal auditory meatus.

Facial Nerve Neuromas: Report of 10 Cases and Review of the Literature

Neurosurgery ◽  
2002 ◽  
Vol 50 (3) ◽  
pp. 450-456 ◽  
Author(s):  
Jonathan D. Sherman ◽  
Elias Dagnew ◽  
Myles L. Pensak ◽  
Harry R. van Loveren ◽  
John M. Tew
Keyword(s):  
Facial Nerve ◽  
Cerebellopontine Angle ◽  
Internal Auditory Canal ◽  
Hearing Preservation ◽  
Outpatient Basis ◽  
Nerve Sheath Tumor ◽  
Facial Paresis ◽  
Presenting Symptoms ◽  
Nervus Intermedius

Abstract OBJECTIVE: This study reviewed the management and outcomes of facial neuromas during the past decade at our institution. The goal was to analyze differences in presentation on the basis of location of the facial neuroma, review facial nerve function and hearing preservation postoperatively, and understand the characteristics of patients with tumors limited to the cerebellopontine angle or internal auditory canal. We also report an unusual case of a facial neuroma limited to the nervus intermedius. METHODS: Nine patients with facial neuromas and one with Jacobson's nerve neuroma underwent surgery, and total resection was accomplished in nine patients. A chart review for pre- and postoperative data was performed, after which all patients were evaluated on an outpatient basis. RESULTS: The mean age of the patients was 47 years; mean follow-up time was 33.1 months. The most common presenting symptoms were hearing loss (six patients) and facial paresis (five patients). A total of five patients had progressive (four patients) or recurrent (one patient) facial paresis. No patient experienced worsened hearing as a result of surgery, and one experienced improvement in a conductive hearing deficit. Five patients required cable graft repair of the facial nerve; four improved to House-Brackmann Grade 3 facial paresis. Four of five patients with preserved anatomic continuity of the facial nerve regained normal facial function. There were no surgical complications. No tumors have recurred during follow-up. We report the second nerve sheath tumor limited to the nervus intermedius. CONCLUSION: This series documents that facial neuromas can be resected safely with preservation of facial nerve and hearing function. Preservation of anatomic continuity of the facial nerve should be attempted, and it does not seem to lead to frequent recurrence. Tumors limited to the cerebellopontine angle/internal auditory canal are a unique subset of facial neuromas with characteristics that vary greatly from facial neuromas in other locations, and they are indistinguishable clinically from acoustic neuromas.

Is the middle fossa approach the treatment of choice for intracanalicular vestibular schwannoma?

2005 ◽  
Vol 132 (3) ◽  
pp. 459-466 ◽  
Author(s):  
Vittorio Colletti ◽  
Francesco Fiorino
Keyword(s):  
Facial Nerve ◽  
Vestibular Schwannoma ◽  
Selection Criteria ◽  
Surgical Techniques ◽  
Internal Auditory Canal ◽  
Hearing Preservation ◽  
Middle Fossa ◽  
Middle Fossa Approach ◽  
Class A ◽  
Longitudinal Investigation

OBJECTIVES: To compare the 2 surgical techniques most commonly used during vestibular schwannoma (VS) surgery, i.e., the middle fossa (MF) and the retrosigmoid-transmeatal (RS-TM) routes, when hearing preservation is attempted. STUDY DESIGN: A longitudinal study of a series of consecutive patients operated on with the 2 techniques by the same surgeon was conducted. Selection criteria included tumor confined to the internal auditory canal (IAC) with a length ranging from 4 to 12 mm and hearing class A or B. Patients were alternately assigned to 1 of the 2 groups regardless of auditory class and distance of the tumor from the IAC fundus. Thirty-five subjects were operated on with the RS-TM technique and 35 via the MF route. RESULTS: No significant differences in auditory and facial nerve function results between the 2 techniques were observed. The RS-TM approach, however, showed better facial nerve results at discharge. VS size, IAC enlargement, and, particularly, the distance from the IAC fundus were found to influence the postoperative results more than the type of approach itself. CONCLUSIONS: The MF approach has been described as being the better technique for VS surgery in terms of auditory results. However, this claim lacks statistical substantiation because no prospective studies are to be found in the literature. The present longitudinal investigation shows that the MF approach does not afford any particular advantages over the RS-TM route in terms of auditory results in intracanalicular VS, with the exception of tumors reaching the IAC fundus.

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