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Constanzo F, Teixeira BCDA, Sens P, Escuissato D, Ramina R. Cerebellopontine angle schwannomas arising from the intermediate nerve: a scoping review. Neurosurg Rev 2019; 43:1431-1441. [PMID: 31522300 DOI: 10.1007/s10143-019-01173-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 08/27/2019] [Accepted: 08/30/2019] [Indexed: 10/26/2022]
Abstract
Intermediate nerve schwannomas (INS) are extremely rare lesions in literature. They have been described mimicking facial nerve schwannomas, but not vestibular schwannomas (VS). We aimed to review the previously published cases, as well as the evidence to believe that they are far more common, though usually misdiagnosed as facial or VS. We performed a review of PubMed/Medline and Embase of "intermediate nerve schwannoma," "facial nerve schwannoma," "greater superficial petrosal nerve schwannoma," "geniculate ganglion schwannoma," and "chorda tympani schwannoma" to identify all cases of INS, following the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) statement. Furthermore, 2 cases operated at our center are shown to exemplify the proposed hypotheses. No article was excluded from review. Thirteen cases of INS, 11 cases of chorda tympani schwannoma, and 18 cases of greater superficial petrosal nerve schwannoma were found in literature. In facial nerve schwannomas, the predilection of schwannomas for sensory nerves, and the ability to preserve the motor facial nerve during tumor resection support the hypothesis of intermediate nerve as the nerve of origin. For VSs, the different arachnoidal arrangement of medial VS, the sharing of pia mater by the intermediate nerve and vestibular nerve, and the medial Obersteiner-Redlich zone of the intermediate nerve, support the hypothesis of intermediate nerve origin of some VS. The correct identification of the intermediate nerve as a nerve of origin of cerebellopontine angle schwannomas is of uttermost importance, especially when mistaken for VS, as this may account for the heterogeneity of facial and cochlear outcomes after surgery.
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Affiliation(s)
- Felipe Constanzo
- Neurosurgery Department, Neurological Institute of Curitiba, Curitiba, Paraná, Brazil.
| | - Bernardo Corrêa de Almeida Teixeira
- Neuroradiology Department, Neurological Institute of Curitiba, Curitiba, Paraná, Brazil.,Internal Medicine Department, Universidade Federal do Paraná, Curitiba, Paraná, Brazil
| | - Patricia Sens
- Otolaryngology Department, Neurological Institute of Curitiba, Curitiba, Paraná, Brazil
| | - Dante Escuissato
- Internal Medicine Department, Universidade Federal do Paraná, Curitiba, Paraná, Brazil
| | - Ricardo Ramina
- Neurosurgery Department, Neurological Institute of Curitiba, Curitiba, Paraná, Brazil
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Could IGF-I levels play a neuroprotective role in patients with large vestibular schwannomas? Future Sci OA 2017; 4:FSO260. [PMID: 29379636 PMCID: PMC5778376 DOI: 10.4155/fsoa-2017-0103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Accepted: 09/29/2017] [Indexed: 11/17/2022] Open
Abstract
Aim To evaluate the possible superiority of outcome in patients with elevated IGF-I levels after vestibular schwannoma (VS) resection. Patients & methods This retrospective study included 65 patients (34 male, 52.3%) with VS operated in between January 2009 and April 2014 (follow-up 3.2 ± 0.7 years). Preoperative or postoperative IGF-I levels were identified for each patient. Results Patients were divided into two groups: Group A (small size tumor), 56 patients; and Group B (large size tumor), 9 cases. IGF-I levels in Group A (195.8 ± 32.9 ng/ml) were compared with those of Group B (242.2 ± 22.2 ng/ml) and were found to have statistically significant difference (p = 0.001). Conclusion Increased IGF-I levels could hold a key role in nerve recovery in patients undergoing surgical resection of large VS.
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Alobaid A, Aref M, Bennardo MR, Farrokhyar F, Reddy K. Facial Nerve Outcome after Vestibular Schwannoma Resection: A Comparative Meta-Analysis of Endoscopic versus Open Retrosigmoid Approach. J Neurol Surg B Skull Base 2015; 76:157-62. [PMID: 25844300 DOI: 10.1055/s-0034-1383858] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2014] [Accepted: 05/06/2014] [Indexed: 10/24/2022] Open
Abstract
The minimal access retrosigmoid endoscopic approach to vestibular schwannoma (VS) resection has been used with promising results. However, it has not been compared with the standard open approach in the literature. We performed a meta-analysis review for all articles describing both approaches for VS from 1996 to 2011. We found 1861 articles. After review and discussion, we narrowed our study to 25 articles, 4 endoscopic and 21 open. The total number of patients was 3026 for open and 790 for endoscopic. The mean tumor sizes in the open and endoscopic series were 2.5 cm and 2.7 cm, respectively. Good facial nerve outcome was achieved in 67% of the open series patients and in 94% of the endoscopic series patients. Other outcomes in the open and endoscopic series were the following: gross total resection, 91% versus 97%; functional hearing, 22.6% versus 46%; wound infection, 1.3% versus 2.6%; and recurrence, 5.4% versus 2.2%. We acknowledge the limitations of our study, but we can state that the endoscopic approach is not inferior to the standard open approach. In expert hands the endoscopic approach can offer as good a result as the open, with potential benefits such as less pain and a shorter length of stay in the hospital. There is a need for more controlled studies for a definitive comparison.
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Affiliation(s)
- Abdullah Alobaid
- Division of Neurosurgery, McMaster University, Hamilton, Ontario, Canada
| | - Mohammed Aref
- Division of Neurosurgery, McMaster University, Hamilton, Ontario, Canada
| | | | | | - Kesava Reddy
- Division of Neurosurgery, McMaster University, Hamilton, Ontario, Canada
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Prell J, Strauss C, Rachinger J, Scheller C, Alfieri A, Herfurth K, Rampp S. The intermedius nerve as a confounding variable for monitoring of the free-running electromyogram. Clin Neurophysiol 2015; 126:1833-9. [PMID: 25655939 DOI: 10.1016/j.clinph.2014.11.028] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 10/08/2014] [Accepted: 11/10/2014] [Indexed: 11/26/2022]
Abstract
OBJECTIVE A-trains, a facial nerve EMG-pattern, are correlated with postoperative functional impairment. However, an unknown confounder is suspected to cause false positive monitoring results. The intermedius nerve contains motor fibers targeting lower facial muscles; their significance for facial nerve monitoring is yet unknown. METHODS Intraoperative videotapes and free-running 9-channel facial nerve EMG assessed from 87 patients undergoing surgery for vestibular schwannoma were evaluated, and presence/absence of an identifiable intermedius nerve was determined. The prognostic value of train time, a quantitative measure for A-train activity, was evaluated for both the groups with and without an identifiable intermedius nerve. RESULTS Correlation between traintime and outcome (Spearman's Rho) rose to 0.73 (p<0.001) when only patients without an identified intermedius nerve were considered, and fell to 0.43 (p<0.05) with the other patient group. This difference was statistically significant (p=0.036), was more prominent in the channels monitoring perioral facial muscles, and resulted from additional A-train activity in patients with an identifiable intermedius nerve. CONCLUSIONS A separate intermedius nerve may be more prone to manipulation, leading to A-train activity without clinical correlate, thus causing false positive monitoring results. SIGNIFICANCE For interpretation of the free-running EMG, the intermedius nerve needs to be taken into account as a confounder.
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Affiliation(s)
- Julian Prell
- Department of Neurosurgery, University of Halle, Ernst-Grube-Str. 40, 06097 Halle, Germany.
| | - Christian Strauss
- Department of Neurosurgery, University of Halle, Ernst-Grube-Str. 40, 06097 Halle, Germany
| | - Jens Rachinger
- Department of Neurosurgery, University of Halle, Ernst-Grube-Str. 40, 06097 Halle, Germany
| | - Christian Scheller
- Department of Neurosurgery, University of Halle, Ernst-Grube-Str. 40, 06097 Halle, Germany
| | - Alex Alfieri
- Department of Neurosurgery, University of Halle, Ernst-Grube-Str. 40, 06097 Halle, Germany
| | - Kirsten Herfurth
- Department of Neurosurgery, University of Halle, Ernst-Grube-Str. 40, 06097 Halle, Germany
| | - Stefan Rampp
- Department of Neurosurgery, University of Halle, Ernst-Grube-Str. 40, 06097 Halle, Germany
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Cayce JM, Wells JD, Malphrus JD, Kao C, Thomsen S, Tulipan NB, Konrad PE, Jansen ED, Mahadevan-Jansen A. Infrared neural stimulation of human spinal nerve roots in vivo. NEUROPHOTONICS 2015; 2:015007. [PMID: 26157986 PMCID: PMC4478764 DOI: 10.1117/1.nph.2.1.015007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 01/12/2015] [Indexed: 05/13/2023]
Abstract
Infrared neural stimulation (INS) is a neurostimulation modality that uses pulsed infrared light to evoke artifact-free, spatially precise neural activity with a noncontact interface; however, the technique has not been demonstrated in humans. The objective of this study is to demonstrate the safety and efficacy of INS in humans in vivo. The feasibility of INS in humans was assessed in patients ([Formula: see text]) undergoing selective dorsal root rhizotomy, where hyperactive dorsal roots, identified for transection, were stimulated in vivo with INS on two to three sites per nerve with electromyogram recordings acquired throughout the stimulation. The stimulated dorsal root was removed and histology was performed to determine thermal damage thresholds of INS. Threshold activation of human dorsal rootlets occurred in 63% of nerves for radiant exposures between 0.53 and [Formula: see text]. In all cases, only one or two monitored muscle groups were activated from INS stimulation of a hyperactive spinal root identified by electrical stimulation. Thermal damage was first noted at [Formula: see text] and a [Formula: see text] safety ratio was identified. These findings demonstrate the success of INS as a fresh approach for activating human nerves in vivo and providing the necessary safety data needed to pursue clinically driven therapeutic and diagnostic applications of INS in humans.
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Affiliation(s)
- Jonathan M. Cayce
- Vanderbilt University, Department of Biomedical Engineering, 5824 Stevenson Center, Station B, Box 351631 Nashville, Tennessee 37235-1631, United States
| | - Jonathon D. Wells
- Lockheed Martin, 22121 20th Avenue SE, Bothell, Washington 98021, United States
| | - Jonathan D. Malphrus
- Vanderbilt University, Department of Biomedical Engineering, 5824 Stevenson Center, Station B, Box 351631 Nashville, Tennessee 37235-1631, United States
| | - Chris Kao
- Vanderbilt University, Department of Neurological Surgery, 1161 21st Avenue, Nashville, Tennessee 37232-2380, United States
| | - Sharon Thomsen
- University of Texas, Department of Biomedical Engineering, Austin, Texas, and 500 Discovery View Drive, Sequim, Washington 98382, United States
| | - Noel B. Tulipan
- Vanderbilt University, Department of Neurological Surgery, 1161 21st Avenue, Nashville, Tennessee 37232-2380, United States
| | - Peter E. Konrad
- Vanderbilt University, Department of Biomedical Engineering, 5824 Stevenson Center, Station B, Box 351631 Nashville, Tennessee 37235-1631, United States
- Vanderbilt University, Department of Neurological Surgery, 1161 21st Avenue, Nashville, Tennessee 37232-2380, United States
| | - E. Duco Jansen
- Vanderbilt University, Department of Biomedical Engineering, 5824 Stevenson Center, Station B, Box 351631 Nashville, Tennessee 37235-1631, United States
- Vanderbilt University, Department of Neurological Surgery, 1161 21st Avenue, Nashville, Tennessee 37232-2380, United States
| | - Anita Mahadevan-Jansen
- Vanderbilt University, Department of Biomedical Engineering, 5824 Stevenson Center, Station B, Box 351631 Nashville, Tennessee 37235-1631, United States
- Vanderbilt University, Department of Neurological Surgery, 1161 21st Avenue, Nashville, Tennessee 37232-2380, United States
- Address all correspondence to: Anita Mahadevan-Jansen, E-mail:
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Acioly MA, Liebsch M, de Aguiar PHP, Tatagiba M. Facial Nerve Monitoring During Cerebellopontine Angle and Skull Base Tumor Surgery: A Systematic Review from Description to Current Success on Function Prediction. World Neurosurg 2013; 80:e271-300. [DOI: 10.1016/j.wneu.2011.09.026] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2011] [Accepted: 09/06/2011] [Indexed: 11/17/2022]
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Oh T, Nagasawa DT, Fong BM, Trang A, Gopen Q, Parsa AT, Yang I. Intraoperative neuromonitoring techniques in the surgical management of acoustic neuromas. Neurosurg Focus 2013; 33:E6. [PMID: 22937857 DOI: 10.3171/2012.6.focus12194] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Unfavorable outcomes such as facial paralysis and deafness were once unfortunate probable complications following resection of acoustic neuromas. However, the implementation of intraoperative neuromonitoring during acoustic neuroma surgery has demonstrated placing more emphasis on quality of life and preserving neurological function. A modern review demonstrates a great degree of recent success in this regard. In facial nerve monitoring, the use of modern electromyography along with improvements in microneurosurgery has significantly improved preservation. Recent studies have evaluated the use of video monitoring as an adjunctive tool to further improve outcomes for patients undergoing surgery. Vestibulocochlear nerve monitoring has also been extensively studied, with the most popular techniques including brainstem auditory evoked potential monitoring, electrocochleography, and direct compound nerve action potential monitoring. Among them, direct recording remains the most promising and preferred monitoring method for functional acoustic preservation. However, when compared with postoperative facial nerve function, the hearing preservation is only maintained at a lower rate. Here, the authors analyze the major intraoperative neuromonitoring techniques available for acoustic neuroma resection.
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Affiliation(s)
- Taemin Oh
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, CA 90095-1761, USA
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Chen DQ, Quan J, Guha A, Tymianski M, Mikulis D, Hodaie M. Three-Dimensional In Vivo Modeling of Vestibular Schwannomas and Surrounding Cranial Nerves With Diffusion Imaging Tractography. Neurosurgery 2011; 68:1077-83. [PMID: 21242825 DOI: 10.1227/neu.0b013e31820c6cbe] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Abstract
BACKGROUND:
Preservation of cranial nerves (CNs) is of paramount concern in the treatment of vestibular schwannomas, particularly in large tumors with thinned and distorted CN fibers. However, imaging of the CN fibers surrounding vestibular schwannomas has been limited with 2-dimensional imaging alone.
OBJECTIVE:
To assess whether tractography of the CN combined with anatomic magnetic resonance imaging of the tumor can provide superior 3-dimensional (3D) visualization of tumor/CN complexes.
METHODS:
Magnetic resonance imaging at 3 T, including diffusion tensor imaging and anatomic images, were analyzed in 3 subjects with vestibular schwannomas using 3D Slicer software. The diffusion tensor images were used to track the courses of trigeminal, abducens, facial, and vestibulocochlear nerves. The anatomic images were used to model the 3D volume reconstruction of the tumor. The 2 sets of images were then superimposed through the use of linear registration.
RESULTS:
Combined 3D tumor modeling and CN tractography can effectively and consistently reconstruct the 3D spatial relationship of CN/tumor complexes and allows superior visualization compared with 2-dimensional imaging. Lateral and superior distortion of the trigeminal nerve was observed in all cases. The position of the facial nerve was primarily anteriorly and inferiorly. The gasserian ganglion and early postganglionic branches could also be visualized.
CONCLUSION:
Tractography and anatomic imaging were successfully combined to demonstrate the precise location of surrounding CN fibers. This technique can be useful in both neuronavigation and radiosurgical planning. Because knowledge of the course of these fibers is of important clinical interest, implementation of this technique may help decrease injury to CNs during treatment of these lesions.
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Affiliation(s)
- David Qixiang Chen
- Division of Neurosurgery and Toronto Western Hospital and University of Toronto, Toronto, Ontario, Canada
| | - Jessica Quan
- Division of Faculty of Medicine, Queen's University, Kingston, Ontario, Canada
| | - Abhijit Guha
- Division of Neurosurgery and Toronto Western Hospital and University of Toronto, Toronto, Ontario, Canada
- Division of Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Michael Tymianski
- Division of Neurosurgery and Toronto Western Hospital and University of Toronto, Toronto, Ontario, Canada
- Division of Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - David Mikulis
- Division of Faculty of Medicine, Queen's University, Kingston, Ontario, Canada
- Division of Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Mojgan Hodaie
- Division of Neurosurgery and Toronto Western Hospital and University of Toronto, Toronto, Ontario, Canada
- Division of Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
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9
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Youssef AS, Downes AE. Intraoperative neurophysiological monitoring in vestibular schwannoma surgery: advances and clinical implications. Neurosurg Focus 2009; 27:E9. [PMID: 19795957 DOI: 10.3171/2009.8.focus09144] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Intraoperative neurophysiological monitoring has become an integral part of vestibular schwannoma surgery. The aim of this article was to review the different techniques of intraoperative neurophysiological monitoring in vestibular schwannoma surgery, identify the clinical impact of certain pathognomonic patterns on postoperative outcomes of facial nerve function and hearing preservation, and highlight the role of postoperative medications in improving delayed cranial nerve dysfunction in the different reported series. METHODS The authors performed a review of the literature regarding intraoperative monitoring in acoustic/vestibular schwannoma surgery. The different clinical series representing different monitoring techniques were reviewed. All the data from clinical series were analyzed in a comprehensive and comparative model. RESULTS Intraoperative brainstem auditory evoked potential monitoring, direct cochlear nerve action potential monitoring, and facial nerve electromyography are the main tools used to assess the functional integrity of an anatomically intact cranial nerve. The identification of pathognomonic brainstem auditory evoked potential and electromyography patterns has been correlated with postoperative functional outcome. Recently, perioperative administration of intravenous hydroxyethyl starch and nimodipine as vasoactive and neuroprotective agents was shown to improve vestibular schwannoma functional outcome in few reported studies. CONCLUSIONS Recent advances in electrophysiological technology have considerably contributed to improvement in functional outcome of vestibular neuroma surgery in terms of hearing preservation and facial nerve paresis. Perioperative intravenous nimodipine and hydroxyethyl starch may be valuable additions to surgery.
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Affiliation(s)
- A Samy Youssef
- Department of Neurosurgery, University of South Florida, Tampa, Florida 33606, USA.
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Strauss C, Bischoff B, Romstöck J, Rachinger J, Rampp S, Prell J. Hearing preservation in medial vestibular schwannomas. J Neurosurg 2008; 109:70-6. [DOI: 10.3171/jns/2008/109/7/0070] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
Vestibular schwannomas (VSs) with no or little extension into the internal auditory canal have been addressed as a clinical subentity carrying a poor prognosis regarding hearing preservation, which is attributed to the initially asymptomatic intracisternal growth pattern. The goal in this study was to assess hearing preservation in patients who underwent surgery for medial VSs.
Methods
A consecutive series of 31 cases in 30 patients with medial VSs (mean size 31 mm) who underwent surgery between 1997 and 2005 via a suboccipitolateral route was evaluated with respect to pre- and postoperative cochlear nerve function, extent of tumor removal, and radiological findings. Intraoperative monitoring of brainstem auditory evoked potentials was performed in all patients with hearing. Patients were reevaluated at a mean of 30 months following surgery.
Results
Preoperative hearing function revealed American Academy of Otolaryngology–Head and Neck Surgery Foundation Classes A and B in 7 patients each, Class C in 4, and D in 9. Four patients presented with deafness. Hearing preservation was achieved in 10 patients (Classes A–C in 2 patients each, and Class D in 4 patients). Tumor removal was complete in all patients with hearing preservation, except for 2 patients with neurofibromatosis. In 4 patients a planned subtotal excision was performed due to the individual's age or underlying disease. In 1 patient a recurrent tumor was completely removed 3 years after the initial procedure.
Conclusions
The cochlear nerve in medial VSs requires special attention due to the atypical intracisternal growth pattern. Even in large tumors, hearing could be preserved in 37% of cases, since the cochlear nerve in medial schwannomas may not exhibit the adherence to the tumor capsule seen in tumors with comparable size involving the internal auditory canal.
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Affiliation(s)
- Christian Strauss
- 1Department of Neurosurgery, Martin Luther University of Halle–Wittenberg, Halle; and
| | - Barbara Bischoff
- 2Department of Neurosurgery, University of Erlangen–Nürnberg, Erlangen, Germany
| | - Johann Romstöck
- 2Department of Neurosurgery, University of Erlangen–Nürnberg, Erlangen, Germany
| | - Jens Rachinger
- 1Department of Neurosurgery, Martin Luther University of Halle–Wittenberg, Halle; and
| | - Stefan Rampp
- 1Department of Neurosurgery, Martin Luther University of Halle–Wittenberg, Halle; and
| | - Julian Prell
- 1Department of Neurosurgery, Martin Luther University of Halle–Wittenberg, Halle; and
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Scheller C, Rachinger J, Prell J, Kornhuber M, Strauss C. Schwannoma of the intermediate nerve. J Neurosurg 2008; 109:144-8. [DOI: 10.3171/jns/2008/109/7/0144] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The intermediate nerve is seldom identified as the site of tumor origin in cerebellopontine angle schwannomas. A 29-year-old man presented with a 6-month history of slowly progressive hearing loss and dizziness; facial nerve weakness was not observed clinically. Magnetic resonance imaging revealed a tumor in the left cerebellopontine angle region extending up to the geniculate ganglion and along the course of the superficial petrosal nerve. A CT scan showed enlargement of the facial nerve canal. Microsurgery was performed via an extended retrosigmoid approach. Intraoperative and electrophysiological findings identified the intermediate nerve as the site of tumor origin.
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Affiliation(s)
| | | | | | - Malte Kornhuber
- 2Neurology, Martin-Luther University of Halle-Wittenberg, Halle, Germany
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Scheller C, Richter HP, Engelhardt M, Köenig R, Antoniadis G. The Influence of Prophylactic Vasoactive Treatment on Cochlear and Facial Nerve Functions after Vestibular Schwannoma Surgery. Neurosurgery 2007; 61:92-7; discussion 97-8. [PMID: 17621023 DOI: 10.1227/01.neu.0000279728.98273.51] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Abstract
OBJECTIVE
Facial nerve paresis and hearing loss are common complications after vestibular schwannoma surgery. Experiments with facial nerves of the rat and retrospectively analyzed clinical studies showed a beneficial effect of vasoactive treatment on the preservation of facial and cochlear nerve functions. This prospective and open-label randomized pilot study is the first study of a prophylactic vasoactive treatment in vestibular schwannoma surgery.
METHODS
Thirty patients were randomized before surgery. One group (n = 14) received a vasoactive prophylaxis consisting of nimodipine and hydroxyethylstarch which was started the day before surgery and was continued until the seventh postoperative day. The other group (n = 16) did not receive preoperative medication. Intraoperative monitoring, including acoustic evoked potentials and continuous facial electromyelograms, was applied to all patients. However, when electrophysiological signs of a deterioration of facial or cochlear nerve function were detected in the group of patients without medication, vasoactive treatment was started immediately. Cochlear and facial nerve function were documented preoperatively, during the first 7 days postoperatively, and again after long-term observation.
RESULTS
Despite the limited number of patients, our results were significant using the Fisher's exact test (small no. of patients) for a better outcome after vestibular schwannoma surgery for both hearing (P = 0.041) and facial nerve (P = 0.045) preservation in the group of patients who received a prophylactic vasoactive treatment.
CONCLUSION
Prophylactic vasoactive treatment consisting of nimodipine and hydroxyethylstarch shows significantly better results concerning preservation of the facial and cochlear nerve function in vestibular schwannoma surgery. The prophylactic use is also superior to intraoperative vasoactive treatment.
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Affiliation(s)
- Christian Scheller
- Department of Neurosurgery, Bezikskrankenhaus Günzburg, University of Ulm, Ulm, Germany.
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Abstract
Object
The facial nerve in vestibular schwannomas (VSs) is located on the ventral tumor surface in more than 90% of cases; other courses are rare. A split facial nerve course with two distinct bundles has thus far been described exclusively for medial extrameatal tumors.
Methods
Between 1996 and 2005, 16 consecutive cases of 241 surgically treated VSs were observed to have distinct splitting of the facial nerve. The mean tumor size measured 27 mm. In one third of the cases, intrameatal tumor extension with obliteration of the fundus was documented. All patients underwent extensive intraoperative neurophysiological monitoring using multichannel electromyography recordings. Patients were reevaluated 12 months after surgery.
In all 16 patients, distinct splitting of the facial nerve was demonstrated. The major portion of the facial nerve followed a typical course on the ventral tumor surface. The smaller nerve portion in all cases ran parallel to the brainstem up to the level of the trigeminal root exit zone and crossed on the cranial tumor pole to the internal auditory canal. The two nerve portions rejoined at the level of the porus acusticus. The smaller portion carried fibers exclusively to the orbicularis oris muscle, whereas the major portion supplied all three branches of the facial nerve.
Conclusions
In VSs, an aberrant course with distinct splitting of the facial nerve adds considerably to the surgical challenge. Long-term facial nerve results are excellent with extensive neurophysiological monitoring, which allows the differentiation and identification of aberrant facial nerve fibers and avoids additional risks to facial nerve preservation.
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Affiliation(s)
- Christian Strauss
- Department of Neurosurgery, Martin-Luther- University of Halle-Wittenberg, Halle, Germany.
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Strauss C, Romstöck J, Fahlbusch R, Rampp S, Scheller C. Preservation of Facial Nerve Function after Postoperative Vasoactive Treatment in Vestibular Schwannoma Surgery. Neurosurgery 2006; 59:577-84; discussion 577-84. [PMID: 16955040 DOI: 10.1227/01.neu.0000230260.95477.0a] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Abstract
OBJECTIVE:
Facial nerve paresis and hearing loss are common complications after vestibular schwannoma surgery. Experimental and clinical studies point to a beneficial effect of nimodipine and hydroxyethyl starch for preservation of cochlear nerve function. A retrospective analysis was undertaken to evaluate the effect of vasoactive treatment on facial nerve outcome.
PATIENTS AND METHODS:
Forty-five patients with vestibular schwannoma removal, intraoperative electromyographic monitoring, and postoperative deterioration of facial nerve function were evaluated. Twenty-five patients underwent vasoactive treatment consisting of nimodipine and hydroxyethyl starch for improvement of hearing outcome. Twenty patients did not receive such treatment. Facial nerve function was evaluated before and after surgery, as well as 1 year after the surgical procedure. Patients were comparable regarding age, tumor size, and preoperative facial nerve function.
RESULTS:
Long-term results of facial nerve function were significantly improved in those patients who experienced severe postoperative deterioration of facial nerve function and received vasoactive treatment as compared with patients who did not receive nimodipine and hydroxyethyl starch after surgery. Treated patients showed a significantly higher rate of complete recovery compared with patients without treatment.
CONCLUSION:
The study points to a potential effect of vasoactive treatment for facial nerve function after vestibular schwannoma surgery. In particular, patients with postoperative disfiguring facial nerve palsy clearly benefit from intravenous hydroxyethyl starch and nimodipine with respect to a long-term socially acceptable facial nerve function.
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Affiliation(s)
- Christian Strauss
- Department of Neurosurgery, University of Halle-Wittenberg, Halle, Germany.
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Taoka T, Hirabayashi H, Nakagawa H, Sakamoto M, Myochin K, Hirohashi S, Iwasaki S, Sakaki T, Kichikawa K. Displacement of the facial nerve course by vestibular schwannoma: Preoperative visualization using diffusion tensor tractography. J Magn Reson Imaging 2006; 24:1005-10. [PMID: 17031835 DOI: 10.1002/jmri.20725] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To preoperatively visualize the course of the facial nerve, which is displaced by vestibular schwannoma, using diffusion tensor (DT) tractography, and to evaluate the agreement with surgical findings. MATERIALS AND METHODS The subjects were eight patients with vestibular schwannoma who had undergone removal surgery. DT MR images were obtained and tracts that were considered to represent the facial nerve were constructed. We assessed the success rate for tract construction and evaluated the agreement between tractography findings and surgery. RESULTS We obtained a tract that connected the internal auditory meatus and brainstem, and was considered to represent the facial nerve in seven of eight cases. The course of the constructed tract agreed with surgical findings in five of these seven cases. One exception was a case in which the tumor was too large to enable intraoperative observation of the facial nerve; however, the facial nerve appeared to be displaced anteriorly at intracapsular resection, in agreement with tractography. In the other case, the schwannoma was mostly cystic. CONCLUSION Tractographs constructed using MR tensor images enabled us to identify tracts considered to represent facial nerves. We consider DT tractography to be a useful tool for preoperatively predicting facial nerve displacement in vestibular schwannoma.
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Affiliation(s)
- Toshiaki Taoka
- Department of Radiology, Nara Medical University, Nara, and Higashiosaka City General Hospital, Osaka, Japan.
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