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Value of intraoperative monitoring of the trigeminal nerve in detection of a superiorly displaced facial nerve during surgery for large vestibular schwannomas. Neurosurg Rev 2021; 45:1343-1351. [PMID: 34533668 DOI: 10.1007/s10143-021-01646-7] [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: 03/12/2021] [Revised: 09/04/2021] [Accepted: 09/10/2021] [Indexed: 10/20/2022]
Abstract
The aim of this study was to investigate the role of trigeminal and facial nerve monitoring in the early identification of a superiorly (anterior and superior (AS)) displaced facial nerve. This prospective study included 24 patients operated for removal of large vestibular schwannomas (VS). The latencies of the electromyographic (EMG) events recorded from the trigeminal and facial nerve innervated muscles after mapping the superior surface of the tumor were analyzed. The mean latency of the recorded compound muscle action potential (CMAP) from the masseter muscle was 3.6 ± 0.5 ms and of the peripherally transmitted responses by volume conduction from the frontalis, o. oculi, nasalis, o. oris, and mentalis muscles was 4.6 ± 0.9, 4.1 ± 0.7, 3.9 ± 0.4, 4.3 ± 0.8, and 4.5 ± 0.6 ms, respectively, after trigeminal nerve stimulation in 24 (100%) patients (pattern I response). In 6 (25%) patients, the mean latency of CMAP on the masseter was 3.3 ± 0.3 ms, and the latencies of the CMAP from the frontalis, o. oculi, nasalis, o. oris, and mentalis muscles were 6.5 ± 1.3, 5.0 ± 1.5, 7.5 ± 1.3, 7.4 ± 0.6, and 7.0 ± 1.5 ms, respectively, longer than those of the peripherally transmitted responses (p = 0.002, p = 0.001, p < 0.001, and p = 0.015, respectively) indicating simultaneous stimulation of both nerves (pattern II response). All patients with this response were later confirmed to have an AS-displaced facial nerve. Recognizing the response resulting from simultaneous stimulation of both the facial and trigeminal nerves is important to help early identification of an AS-displaced facial nerve before it is visible in the surgical field and to avoid misleading information by confusing this pattern for a pure trigeminal nerve response.
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Kartush JM, Rice KS, Minahan RE, Balzer GK, Yingling CD, Seubert CN. Best Practices in Facial Nerve Monitoring. Laryngoscope 2021; 131 Suppl 4:S1-S42. [PMID: 33729584 DOI: 10.1002/lary.29459] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 01/21/2021] [Accepted: 02/02/2021] [Indexed: 12/19/2022]
Abstract
OBJECTIVES/HYPOTHESIS Facial nerve monitoring (FNM) has evolved into a widely used adjunct for many surgical procedures along the course of the facial nerve. Even though majority opinion holds that FNM reduces the incidence of iatrogenic nerve injury, there are few if any studies yielding high-level evidence and no practice guidelines on which clinicians can rely. Instead, a review of the literature and medicolegal cases reveals significant variations in methodology, training, and clinical indications. STUDY DESIGN Literature review and expert opinion. METHODS Given the lack of standard references to serve as a resource for FNM, we assembled a multidisciplinary group of experts representing more than a century of combined monitoring experience to synthesize the literature and provide a rational basis to improve the quality of patient care during FNM. RESULTS Over the years, two models of monitoring have become well-established: 1) monitoring by the surgeon using a stand-alone device that provides auditory feedback of facial electromyography directly to the surgeon, and 2) a team, typically consisting of surgeon, technologist, and interpreting neurophysiologist. Regardless of the setting and the number of people involved, the reliability of monitoring depends on the integration of proper technical performance, accurate interpretation of responses, and their timely application to the surgical procedure. We describe critical steps in the technical set-up and provide a basis for context-appropriate interpretation and troubleshooting of recorded signals. CONCLUSIONS We trust this initial attempt to describe best practices will serve as a basis for improving the quality of patient care while reducing inappropriate variations. LEVEL OF EVIDENCE 4 Laryngoscope, 131:S1-S42, 2021.
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Affiliation(s)
- Jack M Kartush
- Michigan Ear Institute, Farmington Hills, Michigan, U.S.A
| | | | - Robert E Minahan
- Department of Neurology, Georgetown University, Washington, District of Columbia, U.S.A
| | - Gene K Balzer
- Real Time Neuromonitoring Associates, Real Time Neuromonitoring AssociatesNashville, Tennessee, U.S.A
| | - Charles D Yingling
- The Golden Gate Neuromonitoring, Department of Otolaryngology and Head and Neck Surgery, Stanford University, San Francisco, California, U.S.A
| | - Christoph N Seubert
- Department of Anesthesiology, Division of Neuroanesthesiology, University of Florida College of Medicine, Gainesville, Florida, U.S.A
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Predictive Value of Preoperative and Intraoperative Neurophysiology in Evaluating Long-term Facial Function Outcome in Acoustic Neuroma Surgery. Otol Neurotol 2020; 41:530-536. [DOI: 10.1097/mao.0000000000002553] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Ferreira CJA, Sherer M, Anetakis K, Crammond DJ, Balzer JR, Thirumala PD. Neurophysiological Characteristics of Cranial Nerves V- and VII-Triggered EMG in Endoscopic Endonasal Approach Skull Base Surgery. J Neurol Surg B Skull Base 2020; 82:e342-e348. [PMID: 34306959 DOI: 10.1055/s-0040-1701649] [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: 04/05/2018] [Accepted: 12/24/2019] [Indexed: 10/24/2022] Open
Abstract
Objective This study proposes to present reference parameters for trigeminal (V) and facial (VII) cranial nerves (CNs)-triggered electromyography (tEMG) during endoscopic endonasal approach (EEA) skull base surgeries to allow more precise and accurate mapping of these CNs. Study Design We retrospectively reviewed EEA procedures performed at the University of Pittsburgh Medical Center between 2009 and 2015. tEMG recorded in response to stimulation of CN V and VII was analyzed. Analysis of tEMG waveforms included latencies and amplitudes. Medical records were reviewed to determine the presence of perioperative neurologic deficits. Results A total of 28 patients were included. tEMG from 34 CNs (22 V and 12 VII) were analyzed. For CN V, the average onset latency was 2.9 ± 1.1 ms and peak-to-peak amplitude was 525 ± 436.94 μV ( n = 22). For CN VII, the average onset latency and peak-to-peak amplitude were 5.1 ± 1.43 ms and 315 ± 352.58 μV for the orbicularis oculi distribution ( n = 09), 5.9 ± 0.67 ms and 517 ± 489.07 μV on orbicularis oris ( n = 08), and 5.3 ± 0.98 ms 303.1 ± 215.3 μV on mentalis ( n = 07), respectively. Conclusion Our data support the notion that onset latency may be a feasible parameter in the differentiation between the CN V and VII during the crosstalk phenomenon in EEA surgeries but the particularities of this type of procedure should be taken into consideration. A prospective analysis with a larger data set is necessary.
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Affiliation(s)
- Carla J A Ferreira
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States
| | - Marcus Sherer
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States
| | - Katherine Anetakis
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States
| | - Donald J Crammond
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States
| | - Jeffrey R Balzer
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States
| | - Parthasarathy D Thirumala
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States
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Technology of intraoperative neuromonitoring by the method of polyprogram electric stimulation at reconstructive neuroplasty operations. КЛИНИЧЕСКАЯ ПРАКТИКА 2020. [DOI: 10.17816/clinpract18812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Introduction. When operating on the face and neck, a technology for intraoperatuve neurophysiological monitoring is used to ensure the right nerve function.
Aim. Development of a technology for the intraoperatuve neuromonitoring and a practical estimation of its efficiency in the reconstructive neuroplasty surgery.
Methods. In 120 patients with the paralysis of mimic muscles after the removal of a cerebellopontine angle neuroma and a facial nerve damage, neuroplasty was performed to restore the innervation. An original technique was developed for identification and monitoring of the functional state of the nerves and muscles intraoperative visual neuromonitoring (IOVNM). Its concept consists in electric stimulation of the nerves within the surgical field and visual observation of the response muscular contractions. A special ESVM-1 electric stimulator with a set of built-in test programs has been created. The control of the instrument, selection of tests, their launch, visual observation of the reactions and the intraoperative monitoring itself are performed by the operating surgeon.
Results. The presented technology eliminates the need for a complex equipment for neurophysiological monitoring and does not require the participation of a specialist in neurophysiology.
Conclusion. The use of IOVNM during the operation provides an opportunity to assess the functional state of the facial nerve and mimic muscles, to optimize the operation scheme and accelerate its implementation.
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Baek JS, Park SK, Kim DJ, Park CW, Lim SH, Lee JH, Cho YK. Facial Motor Evoked Potential Techniques and Functional Prediction during Cerebello-pontine Angle Surgery. KOREAN JOURNAL OF CLINICAL LABORATORY SCIENCE 2018. [DOI: 10.15324/kjcls.2018.50.4.470] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Jae-Seung Baek
- Department of Neurology, Samsung Medical Center, Seoul, Korea
| | - Sang-Ku Park
- Department of Neurology, Samsung Medical Center, Seoul, Korea
| | - Dong-Jun Kim
- Department of Neurology, Samsung Medical Center, Seoul, Korea
| | - Chan-Woo Park
- Department of Neurology, Samsung Medical Center, Seoul, Korea
| | - Sung-Hyuk Lim
- Department of Neurology, Samsung Medical Center, Seoul, Korea
| | - Jang Ho Lee
- Department of Clinical Laboratory Science, Semyung University, Jecheon, Korea
| | - Young-Kuk Cho
- Department of Medical Laboratory Science, Seoyeong University, Gwangju, Korea
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The utility of “low current” stimulation threshold of intraoperative electromyography monitoring in predicting facial nerve function outcome after vestibular schwannoma surgery: a prospective cohort study of 103 large tumors. J Neurooncol 2018; 138:383-390. [DOI: 10.1007/s11060-018-2806-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 02/14/2018] [Indexed: 10/18/2022]
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Breen JT, Carlson ML, Voss SG, Link MJ, Driscoll CL, Neff BA. Intracranial supramaximal facial nerve stimulation: a murine model. Am J Otolaryngol 2014; 35:164-70. [PMID: 24315628 DOI: 10.1016/j.amjoto.2013.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2013] [Accepted: 09/14/2013] [Indexed: 10/25/2022]
Abstract
PURPOSE Supramaximal facial nerve stimulation is an applied current sufficient to evoke a maximal electromyographic response of facial musculature. It is used during cerebellopontine angle surgery for prognostication of postoperative nerve function. We utilized a rat model to examine safe parameters for intracranial electrical stimulation. MATERIALS AND METHODS Intracranial facial nerve stimulation with electromyographic monitoring of 14 rats was performed. Supramaximal current level was determined and 50 additional pulses of supramaximal (4 rats), 3 times supramaximal (4), 10 times supramaximal (3), or zero (3) current were applied. To monitor progression of facial nerve injury, video recordings of vibrissae movements and eye closure were captured at 1, 3 and 28 days after surgery; animals were sacrificed on day 28, when nerve morphometry was performed. RESULTS One rat in the supramaximal stimulation group (of 4), and one rat in the 10 times supramaximal stimulation group (of 3) demonstrated persistent impairment of facial nerve function as evidenced by decreased amplitude of vibrissae sweeping and eye closure impairment. The remainder of rats in all experimental groups demonstrated symmetric and normal facial nerve function at all time points. CONCLUSIONS A novel animal model for supramaximal stimulation of the rat intracranial facial nerve is described. A small proportion of animals demonstrated functional evidence of nerve injury postoperatively. Function was preserved in some animals after stimulation with current order of magnitude higher than supramaximal levels. Further study with this model is necessary to definitively isolate the effects of surgical trauma from those of supramaximal electrical stimulation.
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Facial nerve palsy after vestibular schwannoma surgery: Dynamic risk-stratification based on continuous EMG-monitoring. Clin Neurophysiol 2014; 125:415-21. [DOI: 10.1016/j.clinph.2013.07.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 07/29/2013] [Accepted: 07/31/2013] [Indexed: 11/18/2022]
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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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Javalkar V, Banerjee AD, Nanda A. Posterior cranial fossa meningiomas. J Neurol Surg B Skull Base 2013; 73:1-10. [PMID: 23372989 DOI: 10.1055/s-0032-1304835] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Accepted: 07/13/2011] [Indexed: 12/13/2022] Open
Abstract
This study evaluated the outcomes, complications, and recurrence rates of posterior cranial fossa meningiomas. We retrospectively reviewed our surgical experience with 64 posterior cranial fossa meningiomas. Mean age was 56 years with a female preponderance (67.2%). Headache was the most common symptom. Retrosigmoid approach was the commonest surgical procedure (23.4%). The incidence of cranial nerve related complications was 28%. Postoperatively facial nerve weakness was observed in 11%. The incidence of cerebrospinal fluid leak was 4.6%. Gross total resection was achieved in 37 patients (58%). Sixteen patients (25%) with residual tumors underwent Gamma knife radiosurgery. Recurrence or tumor progression was observed in 12 patients (18.7%). Operative mortality was 3.1%. At their last follow-up, 93% of the cases achieved Glasgow Outcome Scale scores 4 or 5. Total excision is the ideal goal which can be achieved with meningiomas located in certain location, such as lateral convexity, but for other posterior fossa meningiomas the close proximity of critical structures is a major obstacle in achieving this goal. In practicality, a balance between good functional outcome and extent of resection is important for posterior cranial fossa meningiomas in proximity to critical structures.
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Affiliation(s)
- Vijayakumar Javalkar
- Department of Neurosurgery, Louisiana State University Health Sciences Center, Shreveport, Louisiana
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Zieliński P, Furtak J. Influence of intraoperative neurophysiologic monitoring on the development of surgical dissection techniques. Expert Rev Med Devices 2012; 9:571-5. [PMID: 23249153 DOI: 10.1586/erd.12.52] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Intraoperative neurophysiologic monitoring (IONM) is essential in the preservation of function of nervous system. IONM is thus becoming the gold-standard method in nerve-sparing surgical procedures. Apart from spine and brain surgery, IONM is essential in significantly reducing morbidity in colorectal surgery, prostate and thyroid surgery, as well as in hip replacement, to name a few. IONM measures weak electric nerve potentials and, therefore, it is easily disturbed by other electromagnetic sources. Surgical dissection techniques and devices interfering with IONM make this technique useless because this is dissection that mainly endangers nerve structures. Therefore, there is a need to take into consideration the influence of various dissection techniques on IONM, and to develop or modify inert techniques that are currently not widely used.
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Affiliation(s)
- Piotr Zieliński
- Department of Sports Medicine, Gdansk University of Physical Education and Sport, Gorskiego 1 Str, 80-336 Gdansk, Poland.
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Prell J, Rampp S, Rachinger J, Scheller C, Alfieri A, Marquardt L, Strauss C, Bau V. Botulinum toxin for temporary corneal protection after surgery for vestibular schwannoma. J Neurosurg 2011; 114:426-31. [DOI: 10.3171/2010.4.jns10104] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
High-grade postoperative facial nerve paresis after surgery for vestibular schwannoma with insufficient eye closure involves a risk for severe ocular complications. When conservative measurements are not sufficient, conventional invasive treatments include tarsorrhaphy and eyelid loading. In this study, injection of botulinum toxin into the levator palpebrae muscle was investigated as an alternative for temporary iatrogenic eye closure.
Methods
Injection of botulinum toxin was indicated by an interdisciplinary decision (neurosurgery and ophthalmology) in patients with a postoperative facial nerve paresis corresponding to a House-Brackmann Grade of IV or greater and documented abnormalities concerning corneal status such as keratopathia or conjunctival redness. Twenty-five IUs of botulinum toxin were injected transcutaneously and transconjunctivally.
Results
Six of 11 patients with high-grade paresis showed abnormal corneal findings in the early postoperative period. In 4 of these patients, botulinum toxin was injected; 1 patient declined the treatment, and in 1 patient it was not performed because of contralateral blindness. Temporary eye closure was achieved for 2 to 6 months in all cases. In all cases, facial nerve function had recovered sufficiently in terms of eye closure when the effect of botulinum toxin subsided.
Conclusion
The application of botulinum toxin for temporary iatrogenic eye closure is an excellent low-risk and temporary alternative to other invasive measures for the treatment of postoperative high-grade facial nerve paresis when the facial nerve is anatomically intact.
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Affiliation(s)
| | | | | | | | | | | | | | - Viktoria Bau
- 3Department of Ophthalmology, University of Dresden, Germany
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Nanda A, Javalkar V, Banerjee AD. Petroclival meningiomas: study on outcomes, complications and recurrence rates. J Neurosurg 2010; 114:1268-77. [PMID: 21184632 DOI: 10.3171/2010.11.jns10326] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Petroclival meningiomas are notoriously difficult lesions to manage surgically, given the critical neurovascular structures that are intimately associated with the tumors. In this paper, the authors' aim was to review their series of patients with petroclival meningiomas who underwent surgical treatment; emphasis was placed on evaluating modes of presentation, postoperative neurological outcome, complications, and recurrence rates. METHODS Fifty patients underwent surgical treatment for petroclival meningiomas. The majority of the patients were women (72%). The authors retrospectively reviewed the patients' medical records, imaging studies, and pathology reports to analyze presentation, surgical approach, neurological outcomes, complications, and recurrence rates. RESULTS Headache was the most common presentation (58%). The most commonly used approach was the transpetrous approach (in 16 patients), followed by the orbitozygomatic approach (in 13). Gross-total resection was performed in 14 patients (28%), and in the remaining patients there was residual tumor (72%). Eighteen patients with tumor remnants were treated with Gamma Knife surgery. New postoperative cranial neuropathies were noted in 22 patients (44%). The most common cranial nerve (CN) deficit following surgery was CN III dysfunction (in 11 patients) and facial weakness (in 10). In 9 patients, the CN dysfunction was transient (41%), and 7 patients had permanent dysfunction (32%). Eight patients developed hydrocephalus and all required placement of a ventriculoperitoneal shunt. A CSF leak was noted in only 2 patients (4%), and wound dehiscence was noted in 1. The CSF leaks and the wound dehiscence occurred in patients who were undergoing reoperations. Adequate radiographic follow-up (minimum 6 months) was available for 31 patients (62%). The mean follow-up was 22.1 months. In 6 patients, tumor progression or recurrences were noted. The median time to recurrence was 84 months. At the time of discharge from the hospital, 92% of the patients had good outcomes (Glasgow Outcome Scale Scores 4 and 5). Three patients died of causes not directly related to the surgery. CONCLUSIONS Petroclival meningiomas still pose a formidable challenge to neurosurgeons. In their series, the authors used multiple skull base approaches and careful microneurosurgical technique to achieve a good functional outcome (Glasgow Outcome Scale Score 4 or 5) in 92% of patients, although the extent of gross-total resection was only 28%. The authors' primary surgical goal was to achieve maximal tumor resection while maintaining or improving neurological function. The authors favor the treatment of residual tumor or recurrent tumor with stereotactic radiosurgery.
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Affiliation(s)
- Anil Nanda
- Department of Neurosurgery, Louisiana State University Health Sciences Center, Shreveport, Louisiana 71130-33932, USA.
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The value of intraoperative facial nerve electromyography in predicting facial nerve function after vestibular schwannoma surgery. J Clin Neurosci 2010; 17:849-52. [DOI: 10.1016/j.jocn.2010.02.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Accepted: 02/23/2010] [Indexed: 11/20/2022]
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Prell J, Rachinger J, Scheller C, Alfieri A, Strauss C, Rampp S. A Real-Time Monitoring System for the Facial Nerve. Neurosurgery 2010; 66:1064-73; discussion 1073. [DOI: 10.1227/01.neu.0000369605.79765.3e] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Abstract
OBJECTIVE
Damage to the facial nerve during surgery in the cerebellopontine angle is indicated by A-trains, a specific electromyogram pattern. These A-trains can be quantified by the parameter “traintime,” which is reliably correlated with postoperative functional outcome. The system presented was designed to monitor traintime in real-time.
METHODS
A dedicated hardware and software platform for automated continuous analysis of the intraoperative facial nerve electromyogram was specifically designed. The automatic detection of A-trains is performed by a software algorithm for real-time analysis of nonstationary biosignals. The system was evaluated in a series of 30 patients operated on for vestibular schwannoma.
RESULTS
A-trains can be detected and measured automatically by the described method for real-time analysis. Traintime is monitored continuously via a graphic display and is shown as an absolute numeric value during the operation. It is an expression of overall, cumulated length of A-trains in a given channel; a high correlation between traintime as measured by real-time analysis and functional outcome immediately after the operation (Spearman correlation coefficient [ρ] = 0.664, P < .001) and in long-term outcome (ρ = 0.631, P < .001) was observed.
CONCLUSION
Automated real-time analysis of the intraoperative facial nerve electromyogram is the first technique capable of reliable continuous real-time monitoring. It can critically contribute to the estimation of functional outcome during the course of the operative procedure.
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Affiliation(s)
- Julian Prell
- Department of Neurosurgery, University of Halle, Halle, Germany
| | - Jens Rachinger
- Department of Neurosurgery, University of Halle, Halle, Germany
| | | | - Alex Alfieri
- Department of Neurosurgery, University of Halle, Halle, Germany
| | | | - Stefan Rampp
- Department of Neurosurgery, University of Halle, Halle, Germany
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Gragnaniello C, Kamel M, Al-Mefty O. Utilization of Fluorescein for Identification and Preservation of the Facial Nerve and Semicircular Canals for Safe Mastoidectomy. Neurosurgery 2010; 66:204-7. [DOI: 10.1227/01.neu.0000360567.15127.c5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Abstract
OBJECTIVE
Mastoidectomy can be a very challenging procedure for many reasons. The normal anatomy can be distorted because of inflammatory processes and tumors and recurrences. Avoiding injuries to the semicircular canals (SCCs) and facial canal is mandatory, and there is need to find a way to recognize the facial nerve and SCCs for safe performance of mastoidectomy. We describe, as a proof of concept, a novel technique to drill the mastoid while allowing the surgeon to recognize and avoid injuries to vital structures, in the cadaver.
METHODS
Four fresh cadaveric heads (8 sides) were prepared by cannulating the major vessels at the level of the neck. After removal of the mastoid cortex, indocyanine green was injected in the vessels. The sigmoid sinus alongside the facial nerve and SCCs was skeletonized using the drilling guidance provided by the fluorescence. The mucosa covering the air cells of the mastoid is very well vascularized compared with the thick bone representing the outer layer of the SCCs and facial canal. Consequently, after the indocyanine green injection, the mucosa shines whereas the bone does not. The fluorescence guides the drilling displaying air cells that are safe to remove.
RESULTS
Eight mastoidectomies were performed, resulting in optimal drilling with no injuries to the facial canal and SCCs.
CONCLUSION
With this novel technique, it is possible to perfectly skeletonize the facial nerve and the SCCs in the cadaver. We think that this technique can be an adjunct in the armamentarium of trainees that are not familiar with the anatomy of the temporal bone and eventually of neurosurgeons facing lesions that require the removal of various degrees of the mastoid.
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Affiliation(s)
- Cristian Gragnaniello
- Department of Neurosurgery, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Mahmoud Kamel
- Department of Neurosurgery, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Ossama Al-Mefty
- Department of Neurosurgery, University of Arkansas for Medical Sciences, Little Rock, Arkansas
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