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Erturk M, Demircubuk I, Candar E, Sengul G. Comprehensive Morphometric Analysis of the Rhomboid Fossa: Implications for Safe Entry Zones in Brainstem Surgery. World Neurosurg 2024:S1878-8750(24)01463-3. [PMID: 39181240 DOI: 10.1016/j.wneu.2024.08.096] [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: 03/26/2024] [Revised: 08/16/2024] [Accepted: 08/17/2024] [Indexed: 08/27/2024]
Abstract
BACKGROUND The rhomboid fossa (RF) is a crucial anatomical region in brainstem surgery as it contains essential structures such as the reticular formation and cranial nerve nuclei. This study aimed to provide a detailed understanding of the complex microsurgical anatomy of the RF, which is vital for the safe execution of neurosurgical procedures. METHODS Morphometric analysis was conducted on 45 adult human brainstems preserved in 10% formalin. Under 20× magnification, 13 linear measurements were performed using a millimeter graph to identify key anatomical landmarks. RESULTS The RF measured 34.65 mm in length and 22.61 mm in width. The facial colliculus measured 4.26 mm in length on the left and 4.45 mm on the right, with corresponding widths of 3.77 mm and 3.50 mm. The distance between the sulcus limitans incisures was 9.52 mm, and the distance from the upper border of the medullary striae to obex was 11.53 mm. The proximity of the facial colliculus to the median sulcus was measured at 0.86 mm on the right and 0.96 mm on the left. Additionally, 2 safe entry zones-the suprafacial and infrafacial triangles-were identified, offering pathways to reach dorsal pons lesions through the RF. CONCLUSIONS This comprehensive morphometric analysis of the RF enhances the understanding of its intricate anatomy. By describing safe entry zones, the suprafacial and infrafacial triangles, and providing precise measurements of key anatomical features, this study serves as a valuable resource for neurosurgeons in planning and executing brainstem surgeries.
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Affiliation(s)
- Mete Erturk
- Department of Anatomy, School of Medicine, Ege University, Izmir, Turkey
| | - Ibrahim Demircubuk
- Department of Anatomy, Institute of Health Sciences, Ege University, Izmir, Turkey
| | - Esra Candar
- Department of Neuroscience, Institute of Health Sciences, Ege University, Izmir, Turkey
| | - Gulgun Sengul
- Department of Anatomy, School of Medicine, Ege University, Izmir, Turkey; Department of Neuroscience, Institute of Health Sciences, Ege University, Izmir, Turkey.
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Sala F. Intraoperative neurophysiology in pediatric neurosurgery: a historical perspective. Childs Nerv Syst 2023; 39:2929-2941. [PMID: 37776333 PMCID: PMC10613152 DOI: 10.1007/s00381-023-06155-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 09/07/2023] [Indexed: 10/02/2023]
Abstract
INTRODUCTION Intraoperative neurophysiology (ION) has been established over the past three decades as a valuable discipline to improve the safety of neurosurgical procedures with the main goal of reducing neurological morbidity. Neurosurgeons have substantially contributed to the development of this field not only by implementing the use and refinement of ION in the operating room but also by introducing novel techniques for both mapping and monitoring of neural pathways. METHODS This review provides a personal perspective on the evolution of ION in a variety of pediatric neurosurgical procedures: from brain tumor to brainstem surgery, from spinal cord tumor to tethered cord surgery. RESULTS AND DISCUSSION The contribution of pediatric neurosurgeons is highlighted showing how our discipline has played a crucial role in promoting ION at the turn of the century. Finally, a view on novel ION techniques and their potential implications for pediatric neurosurgery will provide insights into the future of ION, further supporting the view of a functional, rather than merely anatomical, approach to pediatric neurosurgery.
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Affiliation(s)
- Francesco Sala
- Section of Neurosurgery, Department of Neurosciences, Biomedicine and Movement Sciences, University Hospital, Verona, Italy.
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Catapano JS, Rumalla K, Srinivasan VM, Lawrence PM, Larson Keil K, Lawton MT. A taxonomy for brainstem cavernous malformations: subtypes of pontine lesions. Part 2: inferior peduncular, rhomboid, and supraolivary. J Neurosurg 2022; 137:1477-1490. [PMID: 35334460 DOI: 10.3171/2022.1.jns212691] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 01/13/2022] [Indexed: 12/26/2022]
Abstract
OBJECTIVE Part 2 of this 2-part series on pontine cavernomas presents the taxonomy for subtypes 4-6: inferior peduncular (IP) (subtype 4), rhomboid (5), and supraolivary (6). (Subtypes 1-3 are presented in Part 1.) The authors have proposed a novel taxonomy for pontine cavernous malformations based on clinical presentation (syndromes) and anatomical location (MRI findings). METHODS The details of taxonomy development are described fully in Part 1 of this series. In brief, pontine lesions (323 of 601 [53.7%] total lesions) were subtyped on the basis of predominant surface presentation identified on preoperative MRI. Neurological outcomes were assessed according to the modified Rankin Scale, with score ≤ 2 defined as favorable. RESULTS The 323 pontine brainstem cavernous malformations were classified into 6 distinct subtypes: basilar (6 [1.9%]), peritrigeminal (53 [16.4%]), middle peduncular (100 [31.0%]), IP (47 [14.6%]), rhomboid (80 [24.8%]), and supraolivary (37 [11.5%]). Subtypes 4-6 are the subject of the current report. IP lesions are located in the inferolateral pons and are associated with acute vestibular syndrome. Rhomboid lesions present to the fourth ventricle floor and are associated with disconjugate eye movements. Larger lesions may cause ipsilateral facial weakness. Supraolivary lesions present to the surface at the ventral pontine underbelly. Ipsilateral abducens palsy is a strong localizing sign for this subtype. A single surgical approach and strategy were preferred for subtypes 4-6: for IP cavernomas, the suboccipital craniotomy and telovelar approach predominated; for rhomboid lesions, the suboccipital craniotomy and transventricular approach were preferred; and for supraolivary malformations, the far lateral craniotomy and transpontomedullary sulcus approach were preferred. Favorable outcomes were observed in 132 of 150 (88%) patients with follow-up. There were no significant differences in outcomes between subtypes. CONCLUSIONS The neurological symptoms and signs associated with a hemorrhagic pontine subtype can help define that subtype clinically with key localizing signs. The proposed taxonomy for pontine cavernous malformation subtypes 4-6 meaningfully guides surgical strategy and may improve patient outcomes.
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Kodama K, Kothbauer KF, Deletis V. Mapping and monitoring of brainstem surgery. HANDBOOK OF CLINICAL NEUROLOGY 2022; 186:151-161. [PMID: 35772884 DOI: 10.1016/b978-0-12-819826-1.00021-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The surgical morbidity of brainstem lesions is higher than in other areas of the central nervous system because the compact brainstem is highly concentrated with neural structures that are often distorted or even unrecognizable under microscopic view. Intraoperative neurophysiologic mapping helps identify critical neural structures to avoid damaging them. With the trans-fourth ventricular floor approach, identifying the facial colliculi and vagal and hypoglossal triangles enables incising and approaching the brainstem through the safe entry zones, the suprafacial or infrafacial triangle, with minimal injury. Corticospinal tract mapping is adopted in the case of brainstem surgery adjacent to the corticospinal tract. Intraoperative neurophysiologic monitoring techniques include motor evoked potentials (MEPs), corticobulbar MEPs, brainstem auditory evoked potentials, and somatosensory evoked potentials. These provide real-time feedback about the functional integrity of neural pathways, and the surgical team can reconsider and correct the surgical strategy accordingly. With multimodal mapping and monitoring, the brainstem is no longer "no man's land," and brainstem lesions can be treated surgically without formidable morbidity and mortality.
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Affiliation(s)
- Kunihiko Kodama
- Department of Neurosurgery, Shinshu University School of Medicine, Matsumoto, Japan.
| | - Karl F Kothbauer
- Formerly Department of Neurosurgery, University of Basel and Division of Neurosurgery, Luzerner Kantonsspital, Lucerne, Switzerland
| | - Vedran Deletis
- Department of Neurosurgery, University Hospital Dubrava, Zagreb, Croatia; Albert Einstein College of Medicine, New York, NY, United States
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Bertalanffy H, Ichimura S, Kar S, Tsuji Y, Huang C. Optimal access route for pontine cavernous malformation resection with preservation of abducens and facial nerve function. J Neurosurg 2020; 135:683-692. [PMID: 33307526 DOI: 10.3171/2020.7.jns201023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 09/01/2021] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The aim of this study was to analyze the differences between posterolateral and posteromedial approaches to pontine cavernous malformations (PCMs) in order to verify the hypothesis that a posterolateral approach is more favorable with regard to preservation of abducens and facial nerve function. METHODS The authors conducted a retrospective analysis of 135 consecutive patients who underwent microsurgical resection of a PCM. The vascular lesions were first classified in a blinded fashion into 4 categories according to the possible or only reasonable surgical access route. In a second step, the lesions were assessed according to which approach was performed and different patient groups and subgroups were determined. In a third step, the modified Rankin Scale score and the rates of permanent postoperative abducens and facial nerve palsies were assessed. RESULTS The largest group in this series comprised 77 patients. Their pontine lesion was eligible for resection from either a posterolateral or posteromedial approach, in contrast to the remaining 3 patient groups in which the lesion location already had dictated a specific surgical approach. Fifty-four of these 77 individuals underwent surgery via a posterolateral approach and 23 via a posteromedial approach. When comparing these 2 patient subgroups, there was a statistically significant difference between postoperative rates of permanent abducens (3.7% vs 21.7%) and facial (1.9% vs 21.7%) nerve palsies. In the entire patient population, the abducens and facial nerve deficit rates were 5.9% and 5.2%, respectively, and the modified Rankin Scale score significantly decreased from 1.6 ± 1.1 preoperatively to 1.0 ± 1.1 at follow-up. CONCLUSIONS The authors' results suggest favoring a posterolateral over a posteromedial access route to PCMs in patients in whom a lesion is encountered that can be removed via either surgical approach. In the present series, the authors have found such a constellation in 57% of all patients. This retrospective analysis confirms their hypothesis in a large patient cohort. Additionally, the authors demonstrated that 4 types of PCMs can be distinguished by preoperatively evaluating whether only one reasonable or two alternative surgical approaches are available to access a specific lesion. The rates of postoperative sixth and seventh nerve palsies in this series are substantially lower than those in the majority of other published reports.
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Affiliation(s)
| | - Shinya Ichimura
- 1International Neuroscience Institute, Hannover, Germany
- 2Department of Neurosurgery, Kawasaki Chuo Clinic, Kawasaki; and
| | - Souvik Kar
- 1International Neuroscience Institute, Hannover, Germany
| | - Yoshihito Tsuji
- 1International Neuroscience Institute, Hannover, Germany
- 3Department of Neurosurgery, Matsubara Tokushukai Hospital, Matsubara, Japan
| | - Caiquan Huang
- 1International Neuroscience Institute, Hannover, Germany
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Tayebi Meybodi A, Hendricks BK, Witten AJ, Hartman J, Tomlinson SB, Cohen-Gadol AA. Virtual Exploration of Safe Entry Zones in the Brainstem: Comprehensive Definition and Analysis of the Operative Approach. World Neurosurg 2020; 140:499-508. [PMID: 32474103 DOI: 10.1016/j.wneu.2020.05.207] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Accepted: 04/28/2020] [Indexed: 11/29/2022]
Abstract
BACKGROUND A detailed and accurate understanding of the intrinsic brainstem anatomy and the interrelationship between its internal tracts and nuclei and external landmarks is of paramount importance for safe and effective brainstem surgery. Using anatomical models can be an important step in increasing such understanding. In the present study, we have shown the applicability of our developed virtual 3-dimensional (3D) model in depicting the safe entry zones (SEZs) to the brainstem. METHODS Accurate 3D virtual models of brainstem elements were created using high-resolution magnetic resonance imaging and computed tomography to depict the brainstem SEZs. RESULTS All the described SEZs to different parts of the brainstem were successfully depicted using our 3D virtual models. CONCLUSIONS The virtual models provide an immersive experience of brainstem anatomy, allowing users to understand the intricacies of the microdissection that is necessary to appropriately work through the brainstem nuclei and tracts toward a particular target. The models provide an unparalleled learning environment to understand the SEZs into the brainstem that can be used for training and research.
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Affiliation(s)
- Ali Tayebi Meybodi
- The Neurosurgical Atlas, Indianapolis, Indiana, USA; Department of Neurosurgery, Rutgers University Medical School, Newark, New Jersey, USA
| | | | - Andrew J Witten
- Department of Neurosurgery, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | | | | | - Aaron A Cohen-Gadol
- The Neurosurgical Atlas, Indianapolis, Indiana, USA; Department of Neurosurgery, Indiana University School of Medicine, Indianapolis, Indiana, USA.
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Cavalcanti DD, Figueiredo EG, Preul MC, Spetzler RF. Anatomical and Objective Evaluation of the Main Surgical Approaches to Pontine Intra-Axial Lesions. World Neurosurg 2019; 121:e207-e214. [DOI: 10.1016/j.wneu.2018.09.077] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 09/07/2018] [Accepted: 09/11/2018] [Indexed: 11/26/2022]
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Rodríguez-Mena R, Piquer-Belloch J, Llácer-Ortega JL, Riesgo-Suárez P, Rovira-Lillo V. 3D microsurgical anatomy of the cortico-spinal tract and lemniscal pathway based on fiber microdissection and demonstration with tractography. Neurocirugia (Astur) 2018; 29:275-295. [PMID: 30153974 DOI: 10.1016/j.neucir.2018.06.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 05/06/2018] [Accepted: 06/03/2018] [Indexed: 10/28/2022]
Abstract
OBJECTIVE To demonstrate tridimensionally the anatomy of the cortico-spinal tract and the medial lemniscus, based on fiber microdissection and diffusion tensor tractography (DTT). MATERIAL AND METHODS Ten brain hemispheres and brain-stem human specimens were dissected and studied under the operating microscope with microsurgical instruments by applying the fiber microdissection technique. Brain magnetic resonance imaging was obtained from 15 healthy subjects using diffusion-weighted images, in order to reproduce the cortico-spinal tract and the lemniscal pathway on DTT images. RESULTS The main bundles of the cortico-spinal tract and medial lemniscus were demonstrated and delineated throughout most of their trajectories, noticing their gross anatomical relation to one another and with other white matter tracts and gray matter nuclei the surround them, specially in the brain-stem; together with their corresponding representation on DTT images. CONCLUSIONS Using the fiber microdissection technique we were able to distinguish the disposition, architecture and general topography of the cortico-spinal tract and medial lemniscus. This knowledge has provided a unique and profound anatomical perspective, supporting the correct representation and interpretation of DTT images. This information should be incorporated in the clinical scenario in order to assist surgeons in the detailed and critic analysis of lesions located inside the brain-stem, and therefore, improve the surgical indications and planning, including the preoperative selection of optimal surgical strategies and possible corridors to enter the brainstem, to achieve safer and more precise microsurgical technique.
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Affiliation(s)
- Ruben Rodríguez-Mena
- Cátedra de Neurociencias - Fundación NISA, CEU Hospital Universitario de la Ribera, Alzira, Valencia, España.
| | - José Piquer-Belloch
- Cátedra de Neurociencias - Fundación NISA, CEU Hospital Universitario de la Ribera, Alzira, Valencia, España
| | - José Luis Llácer-Ortega
- Cátedra de Neurociencias - Fundación NISA, CEU Hospital Universitario de la Ribera, Alzira, Valencia, España
| | - Pedro Riesgo-Suárez
- Cátedra de Neurociencias - Fundación NISA, CEU Hospital Universitario de la Ribera, Alzira, Valencia, España
| | - Vicente Rovira-Lillo
- Cátedra de Neurociencias - Fundación NISA, CEU Hospital Universitario de la Ribera, Alzira, Valencia, España
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Sala F. A spotlight on intraoperative neurophysiological monitoring of the lower brainstem. Clin Neurophysiol 2017; 128:1369-1371. [PMID: 28571911 DOI: 10.1016/j.clinph.2017.04.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 04/29/2017] [Indexed: 11/19/2022]
Affiliation(s)
- Francesco Sala
- Institute of Neurosurgery, University Hospital, Piazzale Stefani 1, 37124 Verona, Italy.
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10
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Iwanaga J, Granger A, Vahedi P, Loukas M, Oskouian RJ, Fries FN, Lotfinia I, Mortazavi MM, Oakes WJ, Tubbs RS. Mapping the Internal Anatomy of the Lateral Brainstem: Anatomical Study with Application to Far Lateral Approaches to Intrinsic Brainstem Tumors. Cureus 2017; 9:e1010. [PMID: 28357160 PMCID: PMC5355003 DOI: 10.7759/cureus.1010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
INTRODUCTION Intramedullary brainstem tumors present a special challenge to the neurosurgeon. Unfortunately, there is no ideal part of the brainstem to incise for approaches to such pathology. Therefore, the present study was performed to identify what incisions on the lateral brainstem would result in the least amount of damage to eloquent tracts and nuclei. Case illustrations are also discussed. MATERIALS AND METHODS Eight human brainstems were evaluated. Based on dissections and the use of standard atlases of brainstem anatomy, the most important deeper brainstem structures were mapped to the surface of the lateral brainstem. RESULTS With these data, we defined superior acute and inferior obtuse corridors for surgical entrance into the lateral brainstem that would minimize injury to deeper tracts and nuclei, the damage to which would result in significant morbidity. CONCLUSIONS To our knowledge, a superficial map of the lateral brainstem for identifying deeper lying and clinically significant nuclei and tracts has not previously been available. Such data might decrease patient morbidity following biopsy or tumor removal or aspiration of brainstem hemorrhage. Additionally, this information can be coupled with the previous literature on approaches into the fourth ventricular floor for more complex, multidimensional lesions.
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Affiliation(s)
| | - Andre Granger
- Department of Anatomical Sciences, St. George's University School of Medicine, Grenada, West Indies
| | | | - Marios Loukas
- Department of Anatomical Sciences, St. George's University School of Medicine, Grenada, West Indies
| | - Rod J Oskouian
- Neurosurgery, Complex Spine, Swedish Neuroscience Institute
| | - Fabian N Fries
- Saarland University Faculty of Medicine, Saarland University Medical Center
| | | | - Martin M Mortazavi
- Department of Neurosurgery, University of Washington School of Medicine, Seattle, WA
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Wanibuchi M, Akiyama Y, Mikami T, Komatsu K, Sugino T, Suzuki K, Kanno A, Ohtaki S, Noshiro S, Mikuni N. Intraoperative Mapping and Monitoring for Rootlets of the Lower Cranial Nerves Related to Vocal Cord Movement. Neurosurgery 2015; 78:829-34. [PMID: 26544957 DOI: 10.1227/neu.0000000000001109] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Damage to the motor division of the lower cranial nerves that run into the jugular foramen leads to hoarseness, dysphagia, and the risk of aspiration pneumonia; therefore, its functional preservation during surgical procedures is important. Intraoperative mapping and monitoring of the motor rootlets at the cerebellomedullary cistern using endotracheal tube electrodes is a safe and effective procedure to prevent its injury. OBJECTIVE To study the location of the somatic and autonomic motor fibers of the lower cranial nerves related to vocal cord movement. METHODS Twenty-four patients with pathologies at the cerebellopontine lesion were studied. General anesthesia was maintained with fentanyl and propofol. A monopolar stimulator was used at amplitudes of 0.05 to 0.1 mA. Both acoustic and visual signals were displayed as vocalis muscle electromyographic activity using endotracheal tube surface electrodes. RESULTS The average number of rootlets was 7.4 (range, 5-10); 75% of patients had 7 or 8 rootlets. As many as 6 rootlets (2-4 in most cases) were responsive in each patient. In 23 of the 24 patients, the responding rootlets congregated on the caudal side. The maximum electromyographic response was predominantly in the most caudal or second most caudal rootlet in 79%. CONCLUSION The majority of motor fibers of the lower cranial nerves run through the caudal part of the rootlets at the cerebellomedullary cistern, and the maximal electromyographic response was elicited at the most caudal or second most caudal rootlet. ABBREVIATION EMG, electromyographic.
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Affiliation(s)
- Masahiko Wanibuchi
- Department of Neurosurgery, Sapporo Medical University School of Medicine, Sapporo, Japan
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Sala F, Coppola A, Tramontano V. Intraoperative neurophysiology in posterior fossa tumor surgery in children. Childs Nerv Syst 2015; 31:1791-806. [PMID: 26351231 DOI: 10.1007/s00381-015-2893-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Accepted: 08/06/2015] [Indexed: 11/29/2022]
Affiliation(s)
- Francesco Sala
- Pediatric Neurosurgery Unit, Institute of Neurosurgery, University Hospital, Piazzale Stefani 1, 37124, Verona, Italy.
| | - Angela Coppola
- Pediatric Neurosurgery Unit, Institute of Neurosurgery, University Hospital, Piazzale Stefani 1, 37124, Verona, Italy
| | - Vincenzo Tramontano
- Intraoperative Neurophysiology Unit, Institute of Neurosurgery, University Hospital, Piazzale Stefani 1, 37124, Verona, Italy
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Yagmurlu K, Rhoton AL, Tanriover N, Bennett JA. Three-dimensional microsurgical anatomy and the safe entry zones of the brainstem. Neurosurgery 2015; 10 Suppl 4:602-19; discussion 619-20. [PMID: 24983443 DOI: 10.1227/neu.0000000000000466] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND There have been no studies of the structure and safe surgical entry zones of the brainstem based on fiber dissection studies combined with 3-dimensional (3-D) photography. OBJECTIVE To examine the 3-D internal architecture and relationships of the proposed safe entry zones into the midbrain, pons, and medulla. METHODS Fifteen formalin and alcohol-fixed human brainstems were dissected by using fiber dissection techniques, ×6 to ×40 magnification, and 3-D photography to define the anatomy and the safe entry zones. The entry zones evaluated were the perioculomotor, lateral mesencephalic sulcus, and supra- and infracollicular areas in the midbrain; the peritrigeminal zone, supra- and infrafacial approaches, acoustic area, and median sulcus above the facial colliculus in the pons; and the anterolateral, postolivary, and dorsal medullary sulci in the medulla. RESULTS The safest approach for lesions located below the surface is usually the shortest and most direct route. Previous studies have often focused on surface structures. In this study, the deeper structures that may be at risk in each of the proposed safe entry zones plus the borders of each entry zone were defined. This study includes an examination of the relationships of the cerebellar peduncles, long tracts, intra-axial segments of the cranial nerves, and important nuclei of the brainstem to the proposed safe entry zones. CONCLUSION Fiber dissection technique in combination with the 3-D photography is a useful addition to the goal of making entry into the brainstem more accurate and safe.
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Affiliation(s)
- Kaan Yagmurlu
- *Department of Neurosurgery, University of Florida, College of Medicine, Gainesville, Florida; ‡Department of Neurosurgery, Cerrahpasa Medical Faculty, Istanbul University, Istanbul, Turkey; §Department of Radiology, University of Florida, College of Medicine, Gainesville, Florida
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Chen LH, Zhang HT, Chen L, Liu LX, Xu RX. Minimally invasive resection of brainstem cavernous malformations: Surgical approaches and clinical experiences with 38 patients. Clin Neurol Neurosurg 2014; 116:72-9. [DOI: 10.1016/j.clineuro.2013.10.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Revised: 05/23/2013] [Accepted: 10/19/2013] [Indexed: 10/26/2022]
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Abstract
The complex neuroanatomy of the brainstem and the additional distortion incurred by intrinsic lesions have previously discouraged aggressive neurosurgical procedures. Safe access to the brainstem and complete lesionectomy has been thwarted by considerable perioperative risk. Brainstem mapping has established itself as one of the means by which modern neurosurgery can improve surgical outcome while decreasing morbidity. It involves the use of neurophysiologic techniques for the identification of critical structures, such as the cranial motor nuclei and their nerves, and the corticobulbar and corticospinal tracts at different stages of the operation. Familiarity with these techniques can map a safe corridor toward a brainstem lesion and guide the surgeon during the resection. By means of reviewing the available literature, we discuss the anatomic, pathophysiologic, technical, and interpretational aspects of brainstem mapping and elaborate on its indications, limitations, and future directions.
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Neurophysiologic monitoring of the spinal accessory nerve, hypoglossal nerve, and the spinomedullary region. J Clin Neurophysiol 2012; 28:587-98. [PMID: 22146361 DOI: 10.1097/wnp.0b013e31824079b3] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
This review of hypoglossal nerve, spinal accessory nerve, and spinomedullary region intraoperative monitoring details pertinent central and extramedullary anatomy, an updated understanding of proper free-run EMG recording methods and recent developments in stimulation technique and instrumentation. Mapping and monitoring the floor of the fourth ventricle, especially the vagal/hypoglossal trigone region, are emphasized. Although cranial nerve transcranial electrical motor evoked potential recordings can afford appreciation of corticobulbar/corticospinal tract function and secure a more dependable measure of proximate extramedullary somatoefferents, the sometimes difficult implementation and the, as yet, unresolved alert criteria of these recordings demand critical appraisal. Nearby and intimately associated cardiochronotropic and barocontrol neural networks are described; their better understanding is recommended as an important adjunct to "routine" neural monitoring. Finally, an Illustrative case is presented to highlight the many strengths and weaknesses of "state of the art" lower cranial nerve/spinomedullary region monitoring.
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Bertalanffy H, Tissira N, Krayenbühl N, Bozinov O, Sarnthein J. Inter- and intrapatient variability of facial nerve response areas in the floor of the fourth ventricle. Neurosurgery 2011; 68:23-31; discussion 31. [PMID: 21206320 DOI: 10.1227/neu.0b013e31820781fb] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Surgical exposure of intrinsic brainstem lesions through the floor of the 4th ventricle requires precise identification of facial nerve (CN VII) fibers to avoid damage. OBJECTIVE To assess the shape, size, and variability of the area where the facial nerve can be stimulated electrophysiologically on the surface of the rhomboid fossa. METHODS Over a period of 18 months, 20 patients were operated on for various brainstem and/or cerebellar lesions. Facial nerve fibers were stimulated to yield compound muscle action potentials (CMAP) in the target muscles. Using the sites of CMAP yield, a detailed functional map of the rhomboid fossa was constructed for each patient. RESULTS Lesions resected included 14 gliomas, 5 cavernomas, and 1 epidermoid cyst. Of 40 response areas mapped, 19 reached the median sulcus. The distance from the obex to the caudal border of the response area ranged from 8 to 27 mm (median, 17 mm). The rostrocaudal length of the response area ranged from 2 to 15 mm (median, 5 mm). CONCLUSION Facial nerve response areas showed large variability in size and position, even in patients with significant distance between the facial colliculus and underlying pathological lesion. Lesions located close to the facial colliculus markedly distorted the response area. This is the first documentation of variability in the CN VII response area in the rhomboid fossa. Knowledge of this remarkable variability may facilitate the assessment of safe entry zones to the brainstem and may contribute to improved outcome following neurosurgical interventions within this sensitive area of the brain.
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Affiliation(s)
- Helmut Bertalanffy
- Klinik für Neurochirurgie, Universitäts-Spital Zürich, Zürich, Switzerland.
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Sekiya T, Matsumoto M, Kojima K, Ono K, Kikkawa YS, Kada S, Ogita H, Horie RT, Viola A, Holley MC, Ito J. Mechanical stress-induced reactive gliosis in the auditory nerve and cochlear nucleus. J Neurosurg 2010; 114:414-25. [PMID: 20367075 DOI: 10.3171/2010.2.jns091817] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Hearing levels following microsurgical treatment gradually deteriorate in a number of patients treated for vestibular schwannoma (VS), especially in the subacute postoperative stage. The cause of this late-onset deterioration of hearing is not completely understood. The aim of this study was to investigate the possibility that reactive gliosis is a contributory factor. METHODS Mechanical damage to nerve tissue is a feature of complex surgical procedures. To explore this aspect of VS treatment, the authors compressed rat auditory nerves with 2 different degrees of injury while monitoring the compound action potentials of the auditory nerve and the auditory brainstem responses. In this experimental model, the axons of the auditory nerve were quantitatively and highly selectively damaged in the cerebellopontine angle without permanent compromise of the blood supply to the cochlea. The temporal bones were processed for immunohistochemical analysis at 1 week and at 8 weeks after compression. RESULTS Reactive gliosis was induced not only in the auditory nerve but also in the cochlear nucleus following mechanical trauma in which the general shape of the auditory brainstem response was maintained. There was a substantial outgrowth of astrocytic processes from the transitional zone into the peripheral portion of the auditory nerve, leading to an invasion of dense gliotic tissue in the auditory nerve. The elongated astrocytic processes ran in parallel with the residual auditory neurons and entered much further into the cochlea. Confocal images disclosed fragments of neurons scattered in the gliotic tissue. In the cochlear nucleus, hypertrophic astrocytic processes were abundant around the soma of the neurons. The transverse diameter of the auditory nerve at and proximal to the compression site was considerably reduced, indicating atrophy, especially in rats in which the auditory nerve was profoundly compressed. CONCLUSIONS The authors found for the first time that mechanical stress to the auditory nerve causes substantial reactive gliosis in both the peripheral and central auditory pathways within 1-8 weeks. Progressive reactive gliosis following surgical stress may cause dysfunction in the auditory pathways and may be a primary cause of progressive hearing loss following microsurgical treatment for VS.
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Affiliation(s)
- Tetsuji Sekiya
- Department of Otolaryngology, Head and Neck Surgery, Kyoto University Graduate School of Medicine, Kyoto, Japan.
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19
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Chazal J, Ghannane H, Sakka L. [Surgical anatomy of the brain stem]. Neurochirurgie 2007; 53:168-81. [PMID: 17498753 DOI: 10.1016/j.neuchi.2007.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2007] [Accepted: 03/21/2007] [Indexed: 10/19/2022]
Abstract
We reviewed the literature on brain stem anatomy, to identify possible and non-hazardous entry zones with a minimum of functional risks. Using the reticular formation defined as a median structure in a coronal plane, we determined six anatomic zones, 3 ventral, 3 dorsal (mesencephalic, pontic, medulla-oblongata). Considering the functional structures surrounding each zone, the possible penetration points are described. There are ventral, one for the mesencephale, one for the pons, one for the medulla oblongata; and dorsal, one for the mesencephale, two for the floor of the 4th ventricle, one for the medulla oblongata.
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Affiliation(s)
- J Chazal
- Service de neurochirurgie A, hôpital Gabriel-Montpied, CHU de Clermont-Ferrand, BP 69, 63003 Clermont-Ferrand cedex 01, France.
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20
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Ito H, Sobue K, So M, Hirate H, Sugiura T, Azami T, Fujita Y, Sasano H, Katsuya H. Intra-operative monitoring of vagal nerve activity with wire electrodes. Acta Anaesthesiol Scand 2006; 50:1304-5. [PMID: 17067331 DOI: 10.1111/j.1399-6576.2006.01159.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A monitoring system for tracking the electromyogram (EMG) of the vocal cords with wire electrodes embedded in an endotracheal tube was designed to identify the recurrent laryngeal nerve during thyroidectomy. Our recent experience in two cases suggests that vagal nerve activity can be correctly detected by recording of the EMG of the vocal cords using a special endotracheal tube embedded with wire electrodes.
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Affiliation(s)
- H Ito
- Department of Anesthesiology and Medical Crisis Management, Nagoya City University Graduate School of Medical Sciences, Mizuho-ku, Nagoya, Japan
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21
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Gläsker S, Pechstein U, Vougioukas VI, Van Velthoven V. Monitoring motor function during resection of tumours in the lower brain stem and fourth ventricle. Childs Nerv Syst 2006; 22:1288-95. [PMID: 16699805 DOI: 10.1007/s00381-006-0101-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2005] [Revised: 11/03/2005] [Indexed: 11/28/2022]
Abstract
OBJECTIVES Even in the days of modern microsurgery, the removal of a brain stem lesion remains a surgical challenge. Especially when operating on children, the prognosis is directly related to the radicality of the resection; however, a radical resection is often associated with surgical morbidity. Intraoperative neuromonitoring could help to minimise the surgical morbidity, but few studies have been performed to clarify the value of this monitoring. We investigated a prospective series of 21 patients with lesions involving the brain stem for the prognostic value and benefits of neuromonitoring. METHODS We performed intraoperative neuromonitoring of cranial nerve function by electromyography (EMG) and motor evoked potential (MEP). The results were correlated with postoperative neurological deficits. CONCLUSIONS There is a good correlation between intraoperative neurophysiological events and postoperative neurological deficits in patients with lesions of the brain stem. In general, transient, prolonged, spontaneous activity in EMG is associated with a transient paresis of the respective muscle, whereas a permanent spontaneous activity is associated with a permanent deficit. Intraoperative neuromonitoring reliably predicts postoperative neurological function in patients with tumours of the lower brain stem and fourth ventricle. This neuromonitoring guides the neurosurgeon in the operation and may decrease surgical morbidity. We recommend using monitoring of MEP and EMG of the lower cranial nerves in surgery on all patients with lesions involving the lower brain stem and fourth ventricle.
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Affiliation(s)
- Sven Gläsker
- Department of Neurosurgery, Neurochirurgische Universitatsklinik, Albert-Ludwigs-University, Breisacherstrasse 64, 79106, Freiburg, Germany
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22
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Morota N, Deletis V. The importance of brainstem mapping in brainstem surgical anatomy before the fourth ventricle and implication for intraoperative neurophysiological mapping. Acta Neurochir (Wien) 2006; 148:499-509; discussion 509. [PMID: 16374568 DOI: 10.1007/s00701-005-0672-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2005] [Accepted: 09/27/2005] [Indexed: 10/25/2022]
Abstract
Brain stem mapping (BSM) is an intraoperative neurophysiological procedure to localize cranial motor nuclei on the floor of the fourth ventricle. BSM enables neurosurgeon to understand functional anatomy on the distorted floor of the fourth ventricle, thus, it is emerging as an indispensable tool for challenging brain stem surgery. The authors described the detail of BSM with the special emphasis on its clinical application for the brain stem lesion. Surgical implications based on the result of brains stem mapping would be also informative before planning a brain stem surgery through the floor of fourth ventricle. Despite the recent advancement of MRI to depict the lesion in the brain stem, BSM remains as the only way to provide surgical anatomy in the operative field. BSM could guide a neurosurgeon to the inside of brain stem while preventing direct damage to the cranial motor nuclei on the floor of the fourth ventricle. It is expected that understanding its advantage and limitations would help neurosurgeon to perform safer surgery to the brain stem lesion.
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Affiliation(s)
- N Morota
- Department of Neurosurgery, National Children's Medical Center, National Center for Child Health and Development, Tokyo, Japan.
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23
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Mikuni N, Satow T, Taki J, Nishida N, Enatsu R, Hashimoto N. Endotracheal tube electrodes to map and monitor activities of the vagus nerve intraoperatively. J Neurosurg 2004; 101:536-40. [PMID: 15352615 DOI: 10.3171/jns.2004.101.3.0536] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
✓ Difficulty swallowing due to damage of the vagus nerve is one of the most devastating complications of surgery in and around the medulla oblongata; therefore, intraoperative anatomical and functional evaluation of this nerve is crucial. The authors applied endotracheal tube surface electrodes to record electromyography (EMG) activity from vocal cords innervated by the vagus nerve. The vagal nucleus or rootlet was electrically stimulated during surgery and vocalis muscle EMG activities were displayed by auditory and visual signals. This technique was used successfully to identify the vagus motor nerve and evaluate its integrity during surgery. The advantages of this method compared with the use of needle electrodes include safe simple electrode placement and stable recording during surgery. In cases involving a pontine cavernoma pressing the nucleus or a jugular foramen tumor encircling the rootlet, this method would be particularly valuable. Additional studies with a larger number of patients are needed to estimate the significance of this method as a means of functional monitoring to predict clinical function.
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Affiliation(s)
- Nobuhiro Mikuni
- Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan.
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25
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Quester R, Schröder R, Klug N. [Optimization of microsurgical operation technique to insert auditory brainstem implants, taking into account the results of a morphometric study]. HNO 2004; 52:706-13. [PMID: 15309251 DOI: 10.1007/s00106-003-0985-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
STATE OF THE ART The surgical placement of auditory brainstem implants to stimulate the cochlear nuclear region in patients with acquired bilateral retrocochlear deafness allows limited restitution of hearing. However, there have been few studies on the topographical relations in the target region, particularly the floor of the IVth ventricle. TOPIC OF THE STUDY Is it possible to obtain more precise anatomical data in order to improve the surgical approaches and techniques for the placement of auditory brainstem implants? AIMS. To obtain a more precise topo- anatomical orientation in the target region for microsurgical lateral and midline approaches or a stereotactic operative strategy. METHODS AND RESULTS Landmarks for the placement of an auditory brainstem implant via the IVth ventricle were examined and measured in a series of formalin-fixed human brainstems ( n=28). These data, and knowledge of their variability, allow a more precise surgical lateral approach. It is essential to precisely localise the target region, as it can only be partly discerned under the microscope during an operation. For this reason, to date its precise localisation has been determined only electrophysiologically. CONCLUSION Exact target localisation improves safety. From an anatomical point of view the midline approach gives the chance to enlarge the indication spectrum for an implant. The anatomical data obtained here could also be integrated into a stereotactic surgical strategy.
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Affiliation(s)
- R Quester
- Zentrum für Neurochirurgie, Klinikum der Universität zu Köln, Seminar für Psychiatrie der Heilpädagogischen Fakultät, Universität zu Köln.
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26
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Tamano Y, Ujiie H, Kawamata T, Hori T. Continuous Laryngoscopic Vocal Cord Monitoring for Vascular Malformation Surgery in the Medulla Oblongata: Technical Note. Neurosurgery 2004; 54:232-5; discussion 235. [PMID: 14683564 DOI: 10.1227/01.neu.0000097519.38937.fd] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2002] [Accepted: 09/04/2003] [Indexed: 11/18/2022] Open
Abstract
Abstract
OBJECTIVE
Resection of lesions located in the medulla oblongata may result in significant morbidity. The most lethal complications are swallowing disturbances, which can lead to aspiration pneumonia. To prevent this problem, the lower cranial nerves can be mapped with recording needles placed in the posterior pharyngeal wall and the tongue. However, mapping alone is not sufficient to preserve the lower cranial nerves and swallowing functions. To overcome this problem, we attempted to devise a method to intraoperatively monitor vocal cord movements with a laryngoscope. We used this method, in addition to other types of brainstem mapping, in three cases.
METHODS
Recording needles were inserted into the posterior pharyngeal wall and the tongue, to record the responses of Cranial Nerves IX and XII. A laryngoscope was inserted orally, for direct observation of vocal cord movements, and was maintained until the end of the operation. The floor of the fourth ventricle was stimulated with a monopolar stimulator. Somatosensory evoked potentials, auditory evoked potentials, and motor evoked potentials were simultaneously monitored.
RESULTS
We were able to confirm synchronized vocal cord adduction with stimulation of the expected vagal trigonum location and to monitor rhythmic vocal cord movements during spontaneous respiration. In all three cases, we removed the lesions without postoperative complications.
CONCLUSION
In addition to intraoperative vocal cord monitoring with a laryngoscope, we could safely determine the optimal location for the first incision in the floor of the fourth ventricle. Potentially lethal postoperative complications can be avoided with brainstem mapping and vocal cord monitoring.
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Affiliation(s)
- Yoshinori Tamano
- Department of Neurosurgery, Neurological Institute, Tokyo Women's Medical University, Tokyo, Japan
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27
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Yousry I, Moriggl B, Dieterich M, Naidich TP, Schmid UD, Yousry TA. MR anatomy of the proximal cisternal segment of the trochlear nerve: neurovascular relationships and landmarks. Radiology 2002; 223:31-8. [PMID: 11930045 DOI: 10.1148/radiol.2231010612] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To assess the anatomic features and vascular relationships of the proximal portion of the cisternal segment of the trochlear nerve. MATERIALS AND METHODS In 30 subjects (60 nerves) and in one patient with right superior oblique myokymia (SOM), the anatomy of the trochlear nerve was depicted with three-dimensional (3D) Fourier transformation constructive interference in steady state (CISS) magnetic resonance (MR) imaging, whereas the adjacent vessels were detected with 3D time-of-flight (TOF) MR imaging before and after gadopentetate dimeglumine administration. The images were evaluated with respect to the identification of the trochlear nerve, the distance between the point of exit (PE) and the midline, the visualized length, the vascular relationships, and the distance between the PE and the point of neurovascular contact. RESULTS 3D CISS MR imaging depicted the proximal cisternal segment of the trochlear nerve in the transverse, sagittal, and coronal planes in 57 (95%), 51 (85%), and 48 (80%) of 60 nerves, respectively. The distance from the midline to the PE was 3-9 mm, and the maximum visualized length of the trochlear nerve was 1-14 mm. An arterial-trochlear neurovascular contact was seen at the root exit zone (REZ) in eight (14%) nerves and at a mean distance of 3.4 mm distal to the PE in 29 nerves (51%). The patient with SOM had arterial-trochlear neurovascular contact at the REZ. CONCLUSION Use of 3D CISS sequences and 3D TOF sequences with or without gadopentetate dimeglumine enables accurate identification of the proximal cisternal segment of the trochlear nerve and its neurovascular relationships.
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Affiliation(s)
- Indra Yousry
- Depts of Neuroradiology, Klinikum Grosshadern, Munich, Germany.
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28
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Rosahl SK, Rosahl S, Walter GF, Hussein S, Matthies C, Samii M. Cochlear region of the brainstem. J Neurosurg 2000; 93:724-9. [PMID: 11014562 DOI: 10.3171/jns.2000.93.4.0724] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Strauss C, Romstöck J, Fahlbusch R. Pericollicular approaches to the rhomboid fossa. Part II. Neurophysiological basis. J Neurosurg 1999; 91:768-75. [PMID: 10541233 DOI: 10.3171/jns.1999.91.5.0768] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT The authors describe their technique of electrophysiological mapping to assist pericollicular approaches into the rhomboid fossa. METHODS Surgical approaches to the rhomboid fossa can be optimized by direct electrical stimulation of superficially located nuclei and fibers. Electrophysiological mapping allows identification of facial nerve fibers, nuclei of the abducent and hypoglossal nerves, motor nucleus of the trigeminal nerve, and the ambiguous nucleus. Stimulation at the surface of the rhomboid fossa performed using the threshold technique allows localization above the area that is located closest to the surface. Simultaneous bilateral electromyographic (EMG) recordings from cranial motor nerves obtained during stimulation document the selectivity of evoked EMG responses. With respect to stimulation parameters and based on morphometric measurements, the site of stimulation can be assumed to be the postsynaptic fibers at the axonal cone. Strict limitation to 10 Hz with a maximum stimulation intensity not exceeding 2 mA can be considered safe. Direct side effects of electrical stimulation were not observed. CONCLUSIONS Electrical stimulation based on morphometric data obtained on superficial brainstem anatomy defines two safe paramedian supra- and infracollicular approaches to the rhomboid fossa and is particularly helpful in treating intrinsic brainstem lesions that displace normal anatomical structures.
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Affiliation(s)
- C Strauss
- Department of Neurosurgery, University of Erlangen, Nuremberg, Germany.
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31
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Quester R, Schröder R. Topographic anatomy of the cochlear nuclear region at the floor of the fourth ventricle in humans. J Neurosurg 1999; 91:466-76. [PMID: 10470823 DOI: 10.3171/jns.1999.91.3.0466] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT The development of appropriate methods to stimulate the dorsal and ventral cochlear nucleus by means of an auditory brainstem implant in patients with acquired bilateral anacusis requires a detailed topoanatomical knowledge both of the location and extension of the nuclear surface in the fourth ventricle and lateral recess and of its variability. The goal of this study was to provide that information. Anatomically, it is possible to use a midline surgical approach to the fourth ventricle rather than the translabyrinthine and suboccipital routes of access used hitherto. This is especially useful if severe scarring, which occurs as a result of tumor removal in the cerebellopontine angle, make the orientation and placement of an auditory brainstem implant via a lateral surgical approach difficult. There have been only a few studies, involving single cases and small series of patients, in which the focus was the exact extension of the cochlear nuclei, whose microsurgically relevant position in relation to the surface structures is not known in detail. METHODS Landmarks that are important for the placement of an auditory brainstem implant through the fourth ventricle were examined and measured in a large series of 28 formalin-fixed human brainstems. In all cases, these examinations were supplemented by addition of a histological section series. For the first time values of unfixed fresh brainstem tissue were determined. Anatomical features are discussed with regard to their possible neurosurgical relevance, taking into account inter- and intraindividual variability. CONCLUSIONS The midline approach would provide an opportunity to stimulate the whole area of the dorsal as well as the ventral cochlear nucleus with an auditory brainstem implant.
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Affiliation(s)
- R Quester
- Department of Stereotactic and Functional Neurosurgery, University of Cologne, Germany.
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32
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Cantore G, Missori P, Santoro A. Cavernous angiomas of the brain stem. Intra-axial anatomical pitfalls and surgical strategies. SURGICAL NEUROLOGY 1999; 52:84-93; discussion 93-4. [PMID: 10390181 DOI: 10.1016/s0090-3019(99)00036-1] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
BACKGROUND We review the surgical anatomy of the brain stem in relation to the surgical approaches adopted for treatment of cavernomas and identify possible "safe entry zones" on the anterior face of the brainstem. METHODS Twelve symptomatic patients with cavernoma or telangectasia of the brain stem were surgically treated. The brain stem was divided into the following anatomical areas: ventral medulla, dorsal medulla, dorsal pons, ventral pons, ventral mesencephalon, and dorsal mesencephalon, so that the surgical approach could be "individualized" according to the position of the cavernoma, the nerve fasciculi and nuclei. RESULTS On the anterior surface of the brain stem a medullar paramedian oblique access to the anterolateral sulcus and a paramedian sagittal pons access seem to avoid the main nerve fasciculi and nuclei. CONCLUSIONS Although the parenchymal window produced by the cavernoma is the most important parameter for the choice of approach, fairly safe entry zones may be identified even on the anterior surface of the medulla and pons.
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Affiliation(s)
- G Cantore
- Department of Neurosciences, Neurosurgery I, University of Rome La Sapienza, Italy
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33
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Niemann K, van den Boom R, Haeselbarth K, Afshar F. A brainstem stereotactic atlas in a three-dimensional magnetic resonance imaging navigation system: first experiences with atlas-to-patient registration. J Neurosurg 1999; 90:891-901. [PMID: 10223456 DOI: 10.3171/jns.1999.90.5.0891] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT The authors describe a computer-resident digital representation of a stereotactic atlas of the human brainstem, its semiautomated registration to sagittal fast low-angle shot three-dimensional (3-D) magnetic resonance (MR) imaging data sets in 27 healthy volunteers and 24 neurosurgical patients, and an analysis of the subsequent transforms needed to refine the initial registration. METHODS Contour drawings from the atlas, which offer the 70th percentile of variation of anatomical structures, were interpolated into an isotropic 3-D representation. Initial atlas-to-patient registration was based on the fastigium/ventricular floor plane reference system. The quality of the fit was evaluated using superimposition of the atlas and MR images. If necessary, the atlas was tailored to the individual anatomy by using additional transforms. On average, the atlas had to be stretched by 2 to 6% in the three directions of space. Scale factors varied over a broad range from -8 to +19% and the benefit of visual interactive control of the atlas-to-patient registration was evident. Analysis of distances within the pons measured in the midsagittal MR imaging slices and the required scale factors revealed significant correlations that may be used to reduce the amount of user interaction in the coregistration substantially. In 70.6% of the cases, the atlas had to be shifted in a cranial direction along the brainstem axis (in 25.5% of cases 3-4 mm, in 45.1% of cases 1-2 mm). This was due to a more caudal position of the fastigium cerebelli on the MR images compared with the atlas. CONCLUSIONS This observation, in conjunction with the variability of the height of the fourth ventricle in our MR imaging data (range 6.1-15.2 mm, mean 10.1 mm, standard deviation 1.8 mm) calls into question the role of the fastigium cerebelli as an anatomical landmark for localization within the brainstem.
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Affiliation(s)
- K Niemann
- Department of Neuroanatomy, Rheinisch Westfälische Technische Hochschule, Aachen, Germany.
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34
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Bogucki J, Czernicki Z. Direct brainstem surgery. J Neurosurg 1999; 90:174-5. [PMID: 10413177 DOI: 10.3171/jns.1999.90.1.0174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Bogucki J, Gielecki J, Czernicki Z. The anatomical aspects of a surgical approach through the floor of the fourth ventricle. Acta Neurochir (Wien) 1998; 139:1014-9. [PMID: 9442213 DOI: 10.1007/bf01411553] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In 1993 Kyoshima et al. introduced safe entry zones in the region of the 4th ventricle floor: infrafacial triangle and suprafacial triangle. Is it possible to demarcate these zones precisely in every case intra-operatively? A postmortem study of 40 brainstems of patients who had died of non-brain disease was performed to evaluate the degree of individual morphological and morphometrical variability of the 4th ventricle floor. The purpose of this study was to find constant landmarks and distances within the rhomboid fossa region which would help a neurosurgeon to determine safe approach zones through the 4th ventricle floor to brainstem lesions. Several anatomical landmarks-median sulcus, obex, vestibular area, vagal triangle, hypoglossal triangle-were found to be sufficiently visible in all examined brainstems. However, the facial colliculus which is a border structure between the infrafacial and suprafacial safe approach zone was poorly visible in about 37% of the analyzed material. The striae medullares were not found to be good orientation structures as they were not visible in 30% of the material and exhibited individual variability of a high degree in relation to their number and arrangement. In the morphometrical study analyzed measurements were taken by utilizing the digital image analyzer MULTISCAN. Based on the results obtained the authors suggest new borders of the infrafacial safe approach zone and morphometrical directions to determine the suprafacial safe approach zone in cases when the facial colliculus is not clearly visible or invisible intra-operatively.
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Affiliation(s)
- J Bogucki
- Department of Neurosurgery, Polish Academy of Sciences, Warsaw, Poland
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36
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Strauss C, Lütjen-Drecoll E, Fahlbusch R. Pericollicular surgical approaches to the rhomboid fossa. Part I. Anatomical basis. J Neurosurg 1997; 87:893-9. [PMID: 9384401 DOI: 10.3171/jns.1997.87.6.0893] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A safe paramedian approach to the rhomboid fossa for surgical treatment of intrinsic brainstem lesions is based on detailed knowledge of the morphometric anatomy of superficially located motor structures. The morphometry of the rhomboid fossa is described in this report on the basis of histological studies conducted in six human brainstem specimens, with special emphasis on the colliculus facialis and the trigona nervi hypoglossi and vagi. Morphometric data include analysis of shrinkage factors in each specimen. The colliculus is a landmark for the nervus facialis, oculomotor nuclei, and the paramedian pontine reticular formation. In the surgeon's view from the posterior approach, the colliculus covers an area of 5.7 mm in the mediolateral and 6.8 mm in the craniocaudal direction and is located 0.6 mm lateral to the median sulcus. The fibers of the nervus facialis come as close as 0.2 mm to the surface of the fourth ventricle. The colliculus is located 15.7 mm above the obex. The trigona nervi hypoglossi and vagi cover a rectangular area measuring 3.1 by 6.5 mm and serve as a landmark for lower cranial nerve nuclei. These nuclei are located 0.3 mm lateral to the midline. An area with a maximum extension of 0.9 cm between the colliculus and trigona can be used for an infracollicular paramedian approach. The same applies to a supracollicular approach cranial to the colliculus and caudal to the fibers of the nervus trochlearis within the medullary velum, with a craniocaudal extension of 4 mm. Superficial motor nuclei and fibers can be identified by neurophysiological mapping, which helps to define safe surgical corridors into the rhomboid fossa, thus reducing functional morbidity caused by the operative approach in intrinsic pontine and pontomedullary lesions.
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Affiliation(s)
- C Strauss
- Department of Neurosurgery and Institute of Anatomy, University of Erlangen-Nuremberg, Erlangen, Germany
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37
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Ogata N, Wieser HG, Yonekawa Y. Approach to dorsal pontine lesions via the fourth ventricle with SSEP monitoring: a report of two cases. J Clin Neurosci 1996; 3:373-8. [PMID: 18638905 DOI: 10.1016/s0967-5868(96)90036-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/1995] [Accepted: 12/18/1995] [Indexed: 11/25/2022]
Abstract
Operative morbidity is a limiting factor for the trans-fourth ventricular approach to brain stem lesions. The usefulness of somatosensory evoked potentials (SSEP) in this approach has not been established. Two patients with pontine lesions were operated on with SSEP monitoring using the trans-fourth ventricular approach. One patient had a cavernous haemangioma and the other had a chordoma invading the pons. SSEP remained normal in the first, and a slight transitory decrease of the amplitude was observed in the second patient. The lesions were macroscopically totally removed with minimal postoperative neurological deterioration. In this approach it is assumed that SSEP monitoring was especially helpful for removal of the lesions extending deeply in the pons.
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Affiliation(s)
- N Ogata
- Department of Neurosurgery and Department of Neurology, University Hospital of Zürich, Switzerland
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38
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Morota N, Deletis V, Epstein FJ, Kofler M, Abbott R, Lee M, Ruskin K. Brain stem mapping: neurophysiological localization of motor nuclei on the floor of the fourth ventricle. Neurosurgery 1995; 37:922-9; discussion 929-30. [PMID: 8559341 DOI: 10.1227/00006123-199511000-00011] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
We have improved upon a brain stem mapping technique that can be used to locate cranial motor nuclei on the floor of the fourth ventricle. This technique helped to intraoperatively locate the facial colliculus and the motor nuclei of cranial nerves IX/X and XII in 14 patients undergoing removal of brain stem tumors. The motor nuclei of these cranial nerves are usually located relative to specific anatomic landmarks on the ventricular floor. These landmarks were not evident in most patients studied because of the distorting effects of the tumor. Different points of the floor of the fourth ventricle were electrically stimulated while electromyographic responses were recorded with electrodes inserted in the orbicularis oculi and orbicularis oris muscles, the lateral posterior pharyngeal wall, and the intrinsic muscles of tongue. Mapping was performed before and after tumor resection. The technique was found to be useful for locating cranial motor nuclei before tumor resection. It enabled surgeons to avoid damaging the nuclei when entering the brain stem. This technique, however, has certain limitations. Because this is a mapping technique, not a monitoring technique, continuous monitoring during tumor resection was unavailable. Also, the presence of a muscle response after tumor resection did not always indicate preservation of immediate postoperative function (7 days after surgery) because damage to the corticobulbar tract and/or the underlying neural circuitry was not detectable by mapping. Further research is needed to determine the point of stimulation in the functional motor circuitry and the relationship between intraoperative recordings and postoperative function in the long term.
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Affiliation(s)
- N Morota
- Division of Pediatric Neurosurgery, New York University Medical Center, New York, USA
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40
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Eisner W, Schmid UD, Reulen HJ, Oeckler R, Olteanu-Nerbe V, Gall C, Kothbauer K. The mapping and continuous monitoring of the intrinsic motor nuclei during brain stem surgery. Neurosurgery 1995; 37:255-65. [PMID: 7477777 DOI: 10.1227/00006123-199508000-00010] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
A comprehensive technique was developed for continuous electrophysiological monitoring of intrinsic brain stem motor function during surgery to remove space-occupying lesions in the fourth ventricle and brain stem. The technique is analogous to that used during surgery in the cerebellopontine angle; motor nuclei and peripheral pontine fiber tracts of Cranial Nerves III-XII are identified by the electrical stimulation of structures in the operative field and the evaluation of the compound muscle action potentials recorded from the corresponding muscles of the head. Nerve function is monitored continuously by recording the ongoing electromyographic activity in these same muscles. Broadcasting electromyographic responses through a loudspeaker gives the surgeon immediate feedback on the status of the motor nuclei being monitored. Advantages of this technique include 1) the positive, objective identification of the nuclei and fiber tracts; 2) the continuous feedback on the status of these structures; 3) a safe approach through the fourth ventricle to the lesions in the brain stem; 4) the positive identification of the boundaries between the neoplasm and the motor structures of the rhomboid fossa; and 5) a warning to the surgeon of potentially harmful nerve manipulations (contact, dissection, transection) during surgery. After this technique was used in 16 consecutive operations to remove cavernomas (n = 9), gliomas (n = 4), and other types of tumors (n = 3), surgical and neurological results showed the method to be reliable and simple to perform.
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Affiliation(s)
- W Eisner
- Department of Neurosurgery, Klinikum Grosshadern, Ludwig-Maximilian-University, Munich, Germany
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41
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The Mapping and Continuous Monitoring of the Intrinsic Motor Nuclei during Brain Stem Surgery. Neurosurgery 1995. [DOI: 10.1097/00006123-199508000-00010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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42
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Kuroki A, Møller AR. Microsurgical anatomy around the foramen of Luschka in relation to intraoperative recording of auditory evoked potentials from the cochlear nuclei. J Neurosurg 1995; 82:933-9. [PMID: 7760194 DOI: 10.3171/jns.1995.82.6.0933] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Three cadaveric heads were dissected to investigate the microsurgical anatomy around the foramen of Luschka. It was found possible to place a recording electrode in proximity to the cochlear nuclei by inserting it in the lateral recess of the fourth ventricle through the foramen of Luschka. In operations of the cerebellopontine angle using the retromastoid approach, access to the foramen of Luschka and the lateral recess is obtained by retracting the biventral lobule of the cerebellum in a caudal-rostral direction under a caudal-rostral/medial field of vision. The craniectomy might need to be enlarged a few millimeters in the caudal direction. A wick electrode can be inserted in the lateral recess beneath the choroid plexus in a rostromedial direction and to a depth of approximately 3 to 5 mm from the foramen of Luschka without excessive retraction of the cerebellum. The optimum position for the recording electrode is in the triangle formed by the axis of the cochlear nerve and the glossopharyngeal nerve and by the lip of the foramen of Luschka. The caudal retromastoid approach is more suitable than the translabyrinthine technique for recording from the cochlear nuclei as well as for implantation of stimulating electrodes into the cochlear nuclei for use as hearing prostheses.
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Affiliation(s)
- A Kuroki
- Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pennsylvania, USA
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43
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Møller AR, Jho HD, Yokota M, Jannetta PJ. Contribution from crossed and uncrossed brainstem structures to the brainstem auditory evoked potentials: a study in humans. Laryngoscope 1995; 105:596-605. [PMID: 7769942 DOI: 10.1288/00005537-199506000-00007] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The neural generators of the brainstem auditory evoked potentials (BAEPs) in humans are not completely known. Attempts to identify the anatomical location of the neural generators of the human BAEP based on the results of studies in animals commonly used in auditory experimentation have been difficult because of the considerable anatomical differences between the ascending auditory pathways in humans and animals. The authors of this study compared recordings obtained from different locations on the lateral side of the brainstem in six patients undergoing microvascular decompression surgery for a cranial nerve disorder affecting the fifth cranial nerve (i.e., trigeminal neuralgia). Ipsilateral click stimulation evoked prominent responses from the caudal aspect of the pons up to the junction between the pons and the midbrain, but all components of the responses with latencies shorter than 8 msec had smaller amplitudes when recorded at more rostral locations. Components with latencies in the range of peak V elicited by contralateral click stimulation had their largest amplitudes when recorded from the lateral brainstem at the level of the fourth cranial nerve (thus, close to the inferior colliculus). Earlier components of the contralateral responses (latencies in the range of the latency of peak III) had their largest amplitudes when recorded from the caudal lateral brainstem. The results of this study indicate that the part of the uncrossed auditory pathway that is located rostral to the cochlear nucleus contributes little to the farfield potentials (i.e., BAEP), and it is doubtful whether the contralateral response that can be recorded at the level of the cochlear nucleus contributes noticeably to the BAEP.
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Affiliation(s)
- A R Møller
- Department of Neurological Surgery, University of Pittsburgh School of Medicine, PA, USA
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Bricolo A, Turazzi S. Surgery for gliomas and other mass lesions of the brainstem. Adv Tech Stand Neurosurg 1995; 22:261-341. [PMID: 7495420 DOI: 10.1007/978-3-7091-6898-1_5] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- A Bricolo
- Department of Neurological Surgery, University Hospital of Verona, Italy
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45
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Møller AR, Colletti V, Fiorino FG. Neural conduction velocity of the human auditory nerve: bipolar recordings from the exposed intracranial portion of the eighth nerve during vestibular nerve section. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1994; 92:316-20. [PMID: 7517853 DOI: 10.1016/0168-5597(94)90099-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
We measured the conduction velocity of the intracranial portion of the auditory nerve in 3 patients undergoing vestibular nerve section to treat Ménière's disease. The conduction velocity varied from patient to patient, with an average value of 15.1 m/sec. The latency of peak III of the brain-stem auditory evoked potentials (BAEPs) increased by an average of 0.5 msec as a result of exposure of the eighth nerve, and if that increase is assumed to affect the entire length of the auditory nerve (2.6 cm) evenly, then the corrected estimate of conduction velocity would be 22.0 m/sec. Estimates of conduction velocity based on the interpeak latencies of peaks I and II of the BAEP, assuming that peak II is generated by the mid-portion of the intracranial segment of the auditory nerve, yielded similar values of conduction velocities (about 20 m/sec).
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Affiliation(s)
- A R Møller
- Department of Neurological Surgery, Presbyterian University Hospital, University of Pittsburgh School of Medicine, PA 15213
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46
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Neurosurgical forum. J Neurosurg 1994. [DOI: 10.3171/jns.1994.80.5.0947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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47
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Møller AR, Jannetta PJ, Jho HD. Click-evoked responses from the cochlear nucleus: a study in human. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1994; 92:215-24. [PMID: 7514991 DOI: 10.1016/0168-5597(94)90065-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Recordings from the vicinity of the cochlear nucleus in 9 patients undergoing microvascular decompression operations to relieve hemifacial spasm, trigeminal neuralgia, tinnitus, and disabling positional vertigo were conducted by placing a monopolar electrode in the lateral recess of the fourth ventricle (through the foramen of Luschka), the floor of which is the dorsolateral surface of the dorsal cochlear nucleus. The click-evoked potentials recorded by such an electrode display a slow negative wave with a peak latency of about 6-7 msec on which several sharp peaks are superimposed. None of the peaks in the recordings from the vicinity of the cochlear nucleus coincided with any vertex-positive peaks of the brain-stem auditory evoked potentials. In recordings from the lateral aspect of the floor of the fourth ventricle near the cochlear nucleus 1 patient showed 2 positive peaks, the earliest of which had a latency close to that of peak II and the second of which had a latency close to the negative peak between peaks III and IV of the brain-stem auditory evoked potentials. There is a distinct negative peak in the responses recorded from the midline of the floor of the fourth ventricle, the latency of which is only slightly shorter than that of peak V of the brain-stem auditory evoked potentials, supporting earlier findings that the sharp tip of peak V of the brain-stem auditory evoked potentials is generated by the termination of the lateral lemniscus in the inferior colliculus.
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Affiliation(s)
- A R Møller
- Department of Neurological Surgery, Presbyterian-University Hospital, University of Pittsburgh School of Medicine, PA 15213
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Strauss C, Romstöck J, Nimsky C, Fahlbusch R. Intraoperative identification of motor areas of the rhomboid fossa using direct stimulation. J Neurosurg 1993; 79:393-9. [PMID: 8360737 DOI: 10.3171/jns.1993.79.3.0393] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Intraoperative electrical identification of motor areas within the floor of the fourth ventricle was successfully carried out in a series of 10 patients with intrinsic pontine lesions and lesions infiltrating the brain stem. Direct electrical stimulation was used to identify the facial colliculus and the hypoglossal triangle before the brain stem was entered. Multichannel electromyographic recordings documented selective stimulation effects. The surgical approach to the brain stem was varied according to the electrical localization of these structures. During removal of the lesion, functional integrity was monitored by intermittent stimulation. In lesions infiltrating the floor of the fourth ventricle, stimulation facilitated complete removal. Permanent postoperative morbidity of facial or hypoglossal nerve dysfunction was not observed. Mapping of the floor of the fourth ventricle identifies important surface structures and offers a safe corridor through intact nervous structures during surgery of brain-stem lesions. Reliable identification is particularly important in mass lesions with displacement of normal topographical anatomy.
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Affiliation(s)
- C Strauss
- Department of Neurosurgery, University Erlangen-Nuremberg, Erlangen, Germany
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49
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50
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Katsuta T, Morioka T, Fujii K, Fukui M. Physiological localization of the facial colliculus during direct surgery on an intrinsic brain stem lesion. Neurosurgery 1993; 32:861-3; comment 863. [PMID: 8492867 DOI: 10.1227/00006123-199305000-00025] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
We designed a method for localizing facial colliculus intraoperatively by means of weak stimulation of the 4th ventricular floor and recording the electromyographic response of the facial muscle. This method is applicable clinically to prevent 6th and 7th cranial nerve complications during direct surgery on an intrinsic lesion of the brain stem, in which the normal anatomy of the rhomboid fossa is often distorted.
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Affiliation(s)
- T Katsuta
- Department of Neurosurgery, Faculty of Medicine, Kyushu University, Fukuoka, Japan
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