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Ashram YA, Zohdy YM, Garzon-Muvdi T. Impact of Latency Variations on the Predictive Value of Facial Nerve Proximal-to-Distal Amplitude Ratio during Vestibular Schwannoma Surgery. J Neurol Surg B Skull Base 2024; 85:381-388. [PMID: 38966296 PMCID: PMC11221904 DOI: 10.1055/s-0043-1769761] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 05/03/2023] [Indexed: 07/06/2024] Open
Abstract
Introduction This study highlights the relation between compound muscle action potential (CMAP) latency variations and the predictive value of facial nerve (FN) proximal-to-distal (P/D) amplitude ratio measured at the end of vestibular schwannoma resection. Methods Forty-eight patients underwent FN stimulation at the brainstem (proximal) and internal acoustic meatus (distal) using a current intensity of 2 mA. The proximal latency and the P/D amplitude ratio were assessed. House-Brackmann grades I & II indicated good FN function, and grades III to VI were considered fair/poor function. A P/D amplitude ratio > 0.6 was used as a cutoff to indicate a good FN function, while a ratio of ≤ 0.6 indicated a fair/poor FN function. Results The P/D amplitude ratio was measured for all patients, and the calculated sensitivity (SE), specificity (SP), positive predictive value (PPV), and negative predictive value (NPV) were 85.2, 85.7, 88.5, and 81.8%, respectively. The CMAPs from the mentalis muscle were then classified based on their proximal latency into group I (< 6 ms), group II (6-8 ms), and group III (> 8 ms). The SE, SP, PPV, and NPV became 90.5, 90.9, 95, and 83.3%, respectively, in group II. In group I, SE and NPV increased, whereas SP and PPV decreased. While in group III, SP and PPV increased, whereas SE and NPV decreased. Conclusion At a latency between 6 and 8 ms, the P/D amplitude ratio was predictive of outcomes with high SE and SP. When latency was < 6 ms or > 8 ms, the same predictive ability was not observed. Knowing the strengths and limitations is important for understanding the predictive value of the P/D amplitude ratio.
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Affiliation(s)
- Yasmine A. Ashram
- Department of Physiology, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | - Youssef M. Zohdy
- Department of Neurosurgery, Emory University, Atlanta, Georgia, United States
| | - Tomas Garzon-Muvdi
- Department of Neurosurgery, Emory University, Atlanta, Georgia, United States
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Farag AA, Ibrahim AEKSED, Alaghory IM. Clinical Benefits of Facial Nerve Monitoring during Cerebellopontine Angle Surgery. OPEN JOURNAL OF MODERN NEUROSURGERY 2022; 12:9-27. [DOI: 10.4236/ojmn.2022.121002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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Resection of Oculomotor Nerve Lesions Using Continuous Stimulation of the Oculomotor Nerve Proximal to the Lesion: A Technical Report. World Neurosurg 2021; 152:56-60. [PMID: 34139352 DOI: 10.1016/j.wneu.2021.06.013] [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: 05/01/2021] [Revised: 05/31/2021] [Accepted: 06/02/2021] [Indexed: 11/21/2022]
Abstract
BACKGROUND We describe a continuous monitoring method aimed at preserving nerve function during biopsy of lesions on the oculomotor nerve using stimulation of the oculomotor nerve proximal to the lesion. CASE DESCRIPTION A 5-year-old girl with a recurrent left oculomotor nerve palsy and contrast-enhancing left oculomotor nerve mass on magnetic resonance imaging underwent a biopsy of the lesion to aid in its diagnosis. At the time of surgery, needle electrodes were inserted into the superior and inferior rectus muscles percutaneously, and cotton-covered electrodes were implanted into the oculomotor nerve proximal to the lesion. Compound muscle action potentials of the oculomotor nerve were measured continuously by monopolar stimulation. The lesion was mapped by direct stimulation, and the unresponsive area was excised. The amplitude of the compound muscle action potentials decreased during the resection but recovered postoperatively. After resection of the lesion, the compound muscle action potentials remained the same as they were preoperatively. No obvious postoperative oculomotor nerve palsy was observed. CONCLUSIONS This method of continuous monitoring of the function of the oculomotor nerve is simple to use and is suitable for lesions in close proximity to the oculomotor nerve.
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Schackert G, Ralle S, Martin KD, Reiss G, Kowalski M, Sobottka SB, Hennig S, Podlesek D, Sandi-Gahun S, Juratli TA. Vestibular Schwannoma Surgery: Outcome and Complications in Lateral Decubitus Position versus Semi-sitting Position-A Personal Learning Curve in a Series of 544 Cases over 3 Decades. World Neurosurg 2020; 148:e182-e191. [PMID: 33383200 DOI: 10.1016/j.wneu.2020.12.107] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 12/18/2020] [Accepted: 12/19/2020] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To retrospectively evaluate influence of intraoperative positioning (semisitting vs. lateral decubitus) and surgeon's learning curve with regard to functional outcome of patients with vestibular schwannoma. METHODS This study included 544 patients (median age 57 years) and spanned 3 decades: 1991-1999 (n = 103), 2000-2009 (n = 210), and 2010-2019 (n = 231). Surgery was performed in the lateral decubitus position in 318 patients and the semisitting position in 163 patients. Large T3 and T4 tumors were present in 77% of patients. RESULTS Complete tumor removal was achieved in 94.3% of patients. A significant reduction in surgery duration and blood loss was observed over 3 decades for T3 (from 325 to 261 minutes, P < 0.001) and T4 (from 440 to 330 minutes, P < 0.001), but not for T1 and T2, tumors. The semisitting position diminished surgical time in T3 and T4 tumors by 1 more hour (P < 0.001). Over 3 decades, facial nerve outcome improved significantly from 59.8% House-Brackmann grade 1-2 in the first decade to 81.7% in the last decade (P < 0.001). Furthermore, hearing was preserved in 45.3%: 23.3% of patients in the first decade and 50.5% in the last decade (P = 0.03). However, neither facial nerve outcome nor hearing preservation significantly differed in patients operated on in the lateral decubitus versus the semisitting position. The most common complication was cerebrospinal fluid leak (6.1%) followed by hemorrhage (3.5%) and pulmonary embolism (2.2%). CONCLUSIONS Follow-up over 3 decades illustrates a learning curve with significantly improved results. While the semisitting position accelerates the procedure and is associated with reduced blood loss, it does not significantly influence functional outcome.
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Affiliation(s)
- Gabriele Schackert
- Department of Neurosurgery, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.
| | - Susann Ralle
- Department of Neurosurgery, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - K Daniel Martin
- Department of Neurosurgery, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Gilfe Reiss
- Department of Neurosurgery, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Matthias Kowalski
- Department of Neurosurgery, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Stephan B Sobottka
- Department of Neurosurgery, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Silke Hennig
- Department of Neurosurgery, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Dino Podlesek
- Department of Neurosurgery, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Sahr Sandi-Gahun
- Department of Neurosurgery, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Tareq A Juratli
- Department of Neurosurgery, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
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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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6
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Feroze RA, McDowell MM, Balzer J, Crammond DJ, Thirumala P, Sekula RF. Estimation of Intraoperative Stimulation Threshold of the Facial Nerve in Patients Undergoing Microvascular Decompression. J Neurol Surg B Skull Base 2019; 80:599-603. [PMID: 31750045 DOI: 10.1055/s-0038-1677538] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 12/09/2018] [Indexed: 10/27/2022] Open
Abstract
Introduction Facial weakness can result from surgical manipulation of the facial nerve. Intraoperative neuromonitoring reduces functional impairment but no clear guidelines exist regarding interpretation of intraoperative electrophysiological results. Most studies describe subjects with facial nerves encumbered by tumors or those with various grades of facial nerve weakness. We sought to obtain the neurophysiological parameters and stimulation threshold following intraoperative facial nerve triggered electromyography (t-EMG) stimulation during microvascular decompression for trigeminal neuralgia to characterize the response of normal facial nerves via t-EMG. Methods Facial nerve t-EMG stimulation was performed in seven patients undergoing microvascular decompression for trigeminal neuralgia. Using constant current stimulation, single stimulation pulses of 0.025 to 0.2 mA intensity were applied to the proximal facial nerve. Compound muscle action potentials, duration to onset, and termination of t-EMG responses were recorded for the orbicularis oculi and mentalis muscles. Patients were evaluated for facial weakness following the surgical procedure. Results Quantifiable t-EMG responses were generated in response to all tested stimulation currents of 0.025, 0.05, 0.1, and 0.2 mA in both muscles, indicating effective nerve conduction. No patients developed facial weakness postoperatively. Conclusions The presence of t-EMG amplitudes in response to 0.025 mA suggests that facial nerve conduction can take place at lower stimulation intensities than previously reported in patients with tumor burden. Proximal facial nerve stimulation that yields responses with thresholds less than 0.05 mA may be a preferred reference baseline for surgical procedures within the cerebellopontine angle to prevent iatrogenic injury.
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Affiliation(s)
- Rafey A Feroze
- Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
| | - Michael M McDowell
- Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
| | - Jeffrey Balzer
- Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
| | - Donald J Crammond
- Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
| | - Partha Thirumala
- Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
| | - Raymond F Sekula
- Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
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Rampp S, Illert J, Krempler K, Strauss C, Prell J. A-train clusters and the intermedius nerve in vestibular schwannoma patients. Clin Neurophysiol 2019; 130:722-726. [PMID: 30901633 DOI: 10.1016/j.clinph.2019.02.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 01/25/2019] [Accepted: 02/13/2019] [Indexed: 10/27/2022]
Abstract
OBJECTIVE EMG "A-train" activity correlates with postoperative facial palsy after vestibular schwannoma (VS) surgery. An intermedius nerve separate from the facial nerve increases A-trains without significant impact on function. We investigate occurrence of A-train "clusters", A-trains over a majority of channels within a short time frame. METHODS Data from 217 patients with first surgery for VS were evaluated retrospectively. Continuous EMG recorded with 9 channels was evaluated for A-train patterns. "Clusters" of A-trains were identified, i.e. A-trains within 3 seconds over a majority of channels. Relation to a separate intermedius, tumor size and facial palsy was evaluated. RESULTS Correlations between A-trains and postoperative facial palsy were higher in patients without separate intermedius (r = 0.562 versus r = 0.194). Clusters were identified in 107 patients (49.3%), separate intermedius in 109 (50.2%), with significant association of both (p < 0.001, Chi-Square test). Excluding clusters slightly increased correlation of A-trains to facial nerve function. CONCLUSIONS A-train clusters have limited relevance for predicting postoperative paresis. However, they should be regarded as warning signs, suggesting the presence of a separate intermedius nerve. SIGNIFICANCE A-train "clusters" are a sign of hyperactivity of the facial nerve due to a separate intermedius nerve and may confound intraoperative monitoring during VS surgery.
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Affiliation(s)
- Stefan Rampp
- Department of Neurosurgery, University Hospital Halle (Saale), Ernst-Grube-Str. 40, 06120 Halle (Saale), Germany.
| | - Jörg Illert
- Department of Neurosurgery, University Hospital Halle (Saale), Ernst-Grube-Str. 40, 06120 Halle (Saale), Germany
| | - Katja Krempler
- Department of Neurosurgery, University Hospital Halle (Saale), Ernst-Grube-Str. 40, 06120 Halle (Saale), Germany
| | - Christian Strauss
- Department of Neurosurgery, University Hospital Halle (Saale), Ernst-Grube-Str. 40, 06120 Halle (Saale), Germany
| | - Julian Prell
- Department of Neurosurgery, University Hospital Halle (Saale), Ernst-Grube-Str. 40, 06120 Halle (Saale), Germany
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Shkarubo AN, Chernov IV, Ogurtsova AA, Chernov VE, Borisov OV, Koval KV, Andreev DN. Cranial nerve monitoring in endoscopic endonasal surgery of skull base tumors (observing of 23 cases). Chin Neurosurg J 2018; 4:38. [PMID: 32922898 PMCID: PMC7398298 DOI: 10.1186/s41016-018-0146-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 11/01/2018] [Indexed: 12/03/2022] Open
Abstract
Background Preservation of anatomic integrity and function of the cranial nerves during the removal of skull base tumors is one of the most challenging procedures in endoscopic endonasal surgery. It is possible to use intraoperative mapping and identification of the cranial nerves in order to facilitate their preservation. The purpose of this study was to evaluate the effectiveness of intraoperative trigger electromyography in prevention of iatrogenic damage to the cranial nerves. Methods Twenty three patients with various skull base tumors (chordomas, neuromas, pituitary adenomas, meningiomas, cholesteatomas) underwent mapping and identification of cranial nerves during tumor removal using the endoscopic endonasal approach in Department of Neurooncology of Federal State Autonomous Institution “N.N. Burdenko National Medical Research Center of Neurosurgery” of the Ministry of Health of the Russian Federation from 2013 to 2018. During the surgical interventions, mapping and identification of the cranial nerves were carried out using electromyography in triggered mode. The effectiveness of the method was evaluated based on a comparison with a control group (41 patients). Results In the main group of patients, 44 nerves were examined during surgery using triggered electromyography. During the study, the III, V, VI, VII, and XII cranial nerves were identified intraoperatively. Postoperative cranial nerve deficiency was observed in 5 patients in the study group and in 13 patients in the control group. The average length of hospitalization was 9 days. Conclusion We did not receive statistically significant data supporting the fact that intraoperative identification of cranial nerves using trigger electromyography reduces the incidence of postoperative complications in the form of cranial nerve deficits (p = 0.56), but the odds ratio (0.6) suggests a less frequent occurrence of complications in the study group. Based on our experience, the trigger electromyography methodology appears quite promising and requires further research.
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Affiliation(s)
- A N Shkarubo
- Department of Neurooncology, Federal State Autonomous Institution "N.N. Burdenko National Medical Research Center of Neurosurgery" of the Ministry of Health of the Russian Federation, Moscow, Russia
| | - I V Chernov
- Department of Neurooncology, Federal State Autonomous Institution "N.N. Burdenko National Medical Research Center of Neurosurgery" of the Ministry of Health of the Russian Federation, Moscow, Russia
| | - A A Ogurtsova
- Department of Neurophysiology, Federal State Autonomous Institution "N.N. Burdenko National Medical Research Center of Neurosurgery" of the Ministry of Health of the Russian Federation, Moscow, Russia
| | - V E Chernov
- Department of Neurosurgery, N.N. Burdenko Main Military Clinical Hospital of the Ministry of Defense of the Russian Federation, Moscow, Russia
| | - O V Borisov
- Laboratory of Molecular Human Genetics, Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
| | - K V Koval
- Department of Neurooncology, Federal State Autonomous Institution "N.N. Burdenko National Medical Research Center of Neurosurgery" of the Ministry of Health of the Russian Federation, Moscow, Russia
| | - D N Andreev
- Department of Neurooncology, Federal State Autonomous Institution "N.N. Burdenko National Medical Research Center of Neurosurgery" of the Ministry of Health of the Russian Federation, Moscow, Russia
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Tawfik KO, Walters ZA, Kohlberg GD, Lipschitz N, Breen JT, O’Neal K, Zuccarello M, Samy RN. Impact of Motor-Evoked Potential Monitoring on Facial Nerve Outcomes after Vestibular Schwannoma Resection. Ann Otol Rhinol Laryngol 2018; 128:56-61. [DOI: 10.1177/0003489418803969] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objectives: Assess the utility of intraoperative transcranial facial motor-evoked potential (FMEP) monitoring in predicting and improving facial function after vestibular schwannoma (VS) resection. Study Design: Retrospective chart review. Methods: Data were obtained from 82 consecutive VS resections meeting inclusion criteria. Sixty-two cases were performed without FMEP and 20 with FMEP. Degradation of FMEP response was defined as a final-to-baseline amplitude ratio of 0.5 or less. House-Brackmann (HB) grade was assessed preoperatively, postoperatively, at follow-up assessments, and it was compared between pre- and post-FMEP cohorts. Positive predictive value (PPV) and negative predictive value (NPV), sensitivity, and specificity of FMEP degradation in predicting facial weakness were calculated. Results: In the pre-FMEP group, at length of follow-up (LOF) ⩾9 months, 83.9% (52/62) of patients exhibited HB 1-2 outcome. In the post-FMEP cohort, 75.0% (15/20) exhibited HB 1-2 function at LOF ⩾9 months. There was no difference in rates of HB 1-2 outcomes between groups in the immediate postoperative period ( P = .35) or at long-term follow-up ( P = 1.0). With respect to predicting immediate postoperative facial function, FMEP demonstrated high specificity (88.9%) and moderate sensitivity (54.5%). The PPV and NPV for immediate postoperative facial function were 85.7% and 61.5%, respectively. With respect to long-term (⩾9 months LOF) facial function, intraoperative FMEP was moderately sensitive (71.4%) and highly specific (84.6%); PPV was moderate (71.4%), and NPV was high (84.6%). Conclusions: Intraoperative FMEP is highly specific and moderately sensitive in predicting postoperative facial function for patients undergoing VS resection, but its use may not be associated with improved facial nerve outcomes. Level of Evidence: 4
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Affiliation(s)
- Kareem O. Tawfik
- Division of Otolaryngology – Head and Neck Surgery, Department of Surgery, University of California, San Diego School of Medicine, San Diego, CA, USA
| | - Zoe A. Walters
- University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Gavriel D. Kohlberg
- Department of Otolaryngology – Head & Neck Surgery, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Noga Lipschitz
- Department of Otolaryngology – Head & Neck Surgery, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Joseph T. Breen
- Department of Otolaryngology – Head & Neck Surgery, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | | | - Mario Zuccarello
- Department of Neurosurgery, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Ravi N. Samy
- Department of Otolaryngology – Head & Neck Surgery, University of Cincinnati College of Medicine, Cincinnati, OH, USA
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Van Gompel JJ, Carlson ML, Wiet RM, Tombers NM, Devaiah M AK, Lal D, Morcos JJ, Link MJ. A Cross-sectional Survey of the North American Skull Base Society on Vestibular Schwannoma, Part 2: Perioperative Practice Patterns of Vestibular Schwannoma in North America. J Neurol Surg B Skull Base 2017; 79:297-301. [PMID: 29765828 DOI: 10.1055/s-0037-1607976] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Accepted: 09/19/2017] [Indexed: 12/16/2022] Open
Abstract
Introduction Perioperative care of vestibular schwannoma (VS) patients is extremely variable across surgeons and institutions making practice patterns difficult to standardize. No data currently exist detailing this practice variability. Methods The North American Skull Base Society membership was electronically surveyed regarding perioperative care of surgically operated VS patients. Results There were 87 respondents to the survey. Surgical positioning, surgical approach utilized, and perioperative medical adjuncts are quite variable. However, of those performing retrosigmoid approaches, 49% perform this in the supine position, while 33% use a park-bench position with only 2% using the sitting position. In those performing translabyrinthine approaches, 86% perform this in supine position. Although the use of neuromonitoring appears to be standard of care (98%), other than the seventh nerve, there is substantial variability between respondents regarding monitoring of additional cranial nerves. Postoperative antibiotics are used by 65%, postoperative steroids 81%, and postoperative chemical deep vein thrombosis prophylaxis in 68% of survey respondents. Conclusion Although the perioperative adjuncts to VS surgery are variable, there does appear to be a trend in common practice. Therefore, making surgeons aware of these trends may lead to standardized practice or alternatively trials of these variances to instruct which truly improve patient outcomes.
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Affiliation(s)
- Jamie J Van Gompel
- Department of Otolaryngology-Head and Neck Surgery, Mayo Clinic School of Medicine, Rochester, Minnesota, United States.,Department of Neurologic Surgery, Mayo Clinic School of Medicine, Rochester, Minnesota, United States
| | - Matthew L Carlson
- Department of Otolaryngology-Head and Neck Surgery, Mayo Clinic School of Medicine, Rochester, Minnesota, United States.,Department of Neurologic Surgery, Mayo Clinic School of Medicine, Rochester, Minnesota, United States
| | - R Mark Wiet
- Department of Otolaryngology-Head and Neck Surgery, Rush University Medical Center, Chicago, Illinois, United States
| | - Nicole M Tombers
- Department of Otolaryngology-Head and Neck Surgery, Mayo Clinic School of Medicine, Rochester, Minnesota, United States
| | - Anand K Devaiah M
- Department of Otolaryngology-Head and Neck Surgery, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts, United States
| | - Devyani Lal
- Department of Otolaryngology-Head & Neck Surgery, Mayo Clinic College of Medicine, Phoenix, Arizona, United States
| | - Jacques J Morcos
- Department of Neurological Surgery, University of Miami, Miller School of Medicine, Miami, Florida, United States
| | - Michael J Link
- Department of Otolaryngology-Head and Neck Surgery, Mayo Clinic School of Medicine, Rochester, Minnesota, United States.,Department of Neurologic Surgery, Mayo Clinic School of Medicine, Rochester, Minnesota, United States
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Role of Facial Nerve Motor-Evoked Potential Ratio in Predicting Facial Nerve Function in Vestibular Schwannoma Surgery Both Immediate and at 1 Year. Otol Neurotol 2017; 37:1162-7. [PMID: 27525626 DOI: 10.1097/mao.0000000000001137] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To determine whether transcranial electrical stimulation-induced facial motor-evoked potential (FMEP) monitoring of the facial nerve (FN) during vestibular schwannoma (VS) tumor resection can predict both immediate and 1 year postoperative FN functional outcome. DESIGN Prospective consecutive non-comparative observational case series. SETTING Tertiary referral center. MAIN OUTCOME MEASURES Facial function, immediate post operation and at 1 year using House-Brackmann (HB) grading scale. METHODS The study included 367 consecutive patients (men 178; women 189; age 13-81 years) monitored during primary sporadic VS microsurgery between November 2002 and April 2015. Neurofibromatosis type II, revision surgery, previous radiotherapy treatment, preoperative facial nerve weakness, and non-VS cases were excluded retrospectively during analysis of data. Data of facial function were missing from eight patients at 1 year and were excluded. The correlation between the final-to-baseline FMEP ratio and immediate and 1 year facial nerve function was examined. RESULTS Using logistic regression model, the cut-off points of FMEP ratio were 0.62 (PPV 0.96) and 0.59 (PPV 0.98) which predicted satisfactory FN function (HB grades 1 or 2) immediately postoperative and at 1 year after surgery, respectively. CONCLUSION Transcranial electrical stimulation FMEP is a valuable tool for monitoring facial nerve function during resection of vestibular schwannoma. Maintaining a FMEP event-to-baseline ratio of 60% or greater is predictive of satisfactory long-term FN function.
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McNulty BN, Wise S, Cohen DS, Bell J, Bojrab D, LaRouere M, Kircher M, Babu S. Facial Nerve Schwannomas Mimicking as Vestibular Schwannomas. J Neurol Surg B Skull Base 2017; 78:283-287. [PMID: 28725513 PMCID: PMC5515658 DOI: 10.1055/s-0037-1598636] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 12/01/2016] [Indexed: 10/20/2022] Open
Abstract
Objective The objective of this study was to identify preoperative and intraoperative findings that may aid in distinguishing facial nerve schwannomas (FNS) from vestibular schwannomas (VSs), particularly in cases limited to the internal auditory canal (IAC) and cerebellopontine angle (CPA). Study Design This was a retrospective study. Setting This study was set at a Tertiary Referral Center. Patients Seventeen cases from October 2002 to July 2015 with an IAC/CPA mass presumed to be a VS who were found to have a FNS intraoperatively. Main Outcome Measures The main outcome measures included preoperative presentation, intraoperative findings, and subsequent intervention. Results Preoperative hearing loss and imbalance were seen in 70.5 and 64.7%, respectively. Suspicious intraoperative findings included: facial nerve incorporated intimately with the tumor capsule in 12 cases; spontaneous action potentials noted while drilling the bony IAC in 3 cases; and action potentials noted on stimulation of the entire tumor capsule in 10 cases. The mean long-term facial function was House-Brackmann grade II and the mean length of follow-up was 4.86 years. Conclusion FNSs are rare and may be difficult to distinguish from VS preoperatively. Surgical findings that should raise concern include spontaneous action potentials during drilling the bony IAC, absence of a plane of dissection between the facial nerve and tumor, or stimulation of the tumor capsule.
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Affiliation(s)
- Beth N. McNulty
- Michigan Ear Institute, Farmington Hills, Michigan, United States
| | - Sean Wise
- Department of Otology, Neurotology and Skull Base Surgery, Naval Medical Center, San Diego, California, United States
| | - David S. Cohen
- Department of Otolaryngology, Wayne State University, Detroit, Michigan, United States
| | - Jason Bell
- Department of Otolaryngology, Loyola University, Maywood, Illinois, United States
| | - Dennis Bojrab
- Department of Otology, Neurotology and Skull Base Surgery, Michigan Ear Institute, Farmington Hills, Michigan, United States
| | - Michael LaRouere
- Department of Otology, Neurotology and Skull Base Surgery, Michigan Ear Institute, Farmington Hills, Michigan, United States
| | - Matthew Kircher
- Department of Otolaryngology, Loyola University, Maywood, Illinois, United States
| | - Seilesh Babu
- Department of Otology, Neurotology and Skull Base Surgery, Michigan Ear Institute, Farmington Hills, Michigan, United States
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14
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Microsurgical resection of vestibular schwannomas: complication avoidance. J Neurooncol 2016; 130:367-375. [DOI: 10.1007/s11060-016-2260-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 08/27/2016] [Indexed: 10/21/2022]
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Elangovan C, Singh SP, Gardner P, Snyderman C, Tyler-Kabara EC, Habeych M, Crammond D, Balzer J, Thirumala PD. Intraoperative neurophysiological monitoring during endoscopic endonasal surgery for pediatric skull base tumors. J Neurosurg Pediatr 2016; 17:147-155. [PMID: 26517056 DOI: 10.3171/2015.7.peds14403] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT The aim of this study was to evaluate the value of intraoperative neurophysiological monitoring (IONM) using electromyography (EMG), brainstem auditory evoked potentials (BAEPs), and somatosensory evoked potentials (SSEPs) to predict and/or prevent postoperative neurological deficits in pediatric patients undergoing endoscopic endonasal surgery (EES) for skull base tumors. METHODS All consecutive pediatric patients with skull base tumors who underwent EES with at least 1 modality of IONM (BAEP, SSEP, and/or EMG) at our institution between 1999 and 2013 were retrospectively reviewed. Staged procedures and repeat procedures were identified and analyzed separately. To evaluate the diagnostic accuracy of significant free-run EMG activity, the prevalence of cranial nerve (CN) deficits and the sensitivity, specificity, and positive and negative predictive values were calculated. RESULTS A total of 129 patients underwent 159 procedures; 6 patients had a total of 9 CN deficits. The incidences of CN deficits based on the total number of nerves monitored in the groups with and without significant free-run EMG activity were 9% and 1.5%, respectively. The incidences of CN deficits in the groups with 1 staged and more than 1 staged EES were 1.5% and 29%, respectively. The sensitivity, specificity, and negative predictive values (with 95% confidence intervals) of significant EMG to detect CN deficits in repeat procedures were 0.55 (0.22-0.84), 0.86 (0.79-0.9), and 0.97 (0.92-0.99), respectively. Two patients had significant changes in their BAEPs that were reversible with an increase in mean arterial pressure. CONCLUSIONS IONM can be applied effectively and reliably during EES in children. EMG monitoring is specific for detecting CN deficits and can be an effective guide for dissecting these procedures. Triggered EMG should be elicited intraoperatively to check the integrity of the CNs during and after tumor resection. Given the anatomical complexity of pediatric EES and the unique challenges encountered, multimodal IONM can be a valuable adjunct to these procedures.
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Affiliation(s)
| | | | | | - Carl Snyderman
- Departments of 1 Neurological Surgery.,Otolaryngology, University of Pittsburgh Medical Center; and
| | | | | | | | - Jeffrey Balzer
- Departments of 1 Neurological Surgery.,Department of Neuroscience, University of Pittsburgh, Pennsylvania
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Predictive value of intraoperative neurophysiologic monitoring in assessing long-term facial function in grade IV vestibular schwannoma removal. Acta Neurochir (Wien) 2015; 157:1991-7; discussion 1998. [PMID: 26347044 DOI: 10.1007/s00701-015-2571-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 08/27/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND Despite routine use of intraoperative neuromonitoring in acoustic neuroma removal, its application in predicting long-term facial function is limited. METHODS Prospective recording of facial nerve function and subsequent review of intraoperative neurophysiologic data. Stimulation of the facial nerve was performed proximal and distal to the tumor locus after tumor removal with measurement of amplitude and latency responses in the orbicularis oculi and oris muscles. Prospective review of current facial nerve function was performed using the House-Brackmann (HB) scoring system. Good facial function was determined as HB I/II and HB III-VI was considered poor facial function. Minimum follow-up time was 15 months, and averaged 40 months. RESULTS Twenty-four grade IV acoustic neuromas (54 % larger than 4 cm) were completely removed from October 2008 to November 2013. Nine patients (37.5 %) had HB I/II and 15 (62.5 %) had HB III-VI. The poor prognosis group had a higher latency than the good prognosis group (p = 0.045). Lower proximal amplitude was detected in the poor prognosis group (p = 0.046). Lower proximal-to-distal amplitude ratio was also detected in the poor prognosis group (p = 0.052). Amplitude ratio cut-offs of 0.44 and 0.25 were able to predict poor prognosis with sensitivity of 0.73 and 0.4 and specificity of 0.78 and 1, respectively (p = 0.046). CONCLUSIONS Lower proximal amplitude and proximal-distal amplitude ratio were previously reported as predictors of poor facial function in different sizes of vestibular schwannomas. We observed that the same applies specifically for large-sized, completely removed, grade IV tumors. Additionally, we describe a difference in proximal latency time between the good and poor prognosis groups, which was not previously reported.
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IONM evidence: Putting the work and insight of Téllez et al. in context. Clin Neurophysiol 2015; 127:1015-1017. [PMID: 26463475 DOI: 10.1016/j.clinph.2015.09.130] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 09/22/2015] [Accepted: 09/23/2015] [Indexed: 01/14/2023]
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Affiliation(s)
- Marc R Nuwer
- Department of Neurology, David Geffen School of Medicine at UCLA, USA; Department of Clinical Neurophysiology, Ronald Reagan UCLA Medical Center, USA.
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Prell J, Strauss C, Rachinger J, Scheller C, Alfieri A, Herfurth K, Rampp S. The intermedius nerve as a confounding variable for monitoring of the free-running electromyogram. Clin Neurophysiol 2015; 126:1833-9. [PMID: 25655939 DOI: 10.1016/j.clinph.2014.11.028] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 10/08/2014] [Accepted: 11/10/2014] [Indexed: 11/26/2022]
Abstract
OBJECTIVE A-trains, a facial nerve EMG-pattern, are correlated with postoperative functional impairment. However, an unknown confounder is suspected to cause false positive monitoring results. The intermedius nerve contains motor fibers targeting lower facial muscles; their significance for facial nerve monitoring is yet unknown. METHODS Intraoperative videotapes and free-running 9-channel facial nerve EMG assessed from 87 patients undergoing surgery for vestibular schwannoma were evaluated, and presence/absence of an identifiable intermedius nerve was determined. The prognostic value of train time, a quantitative measure for A-train activity, was evaluated for both the groups with and without an identifiable intermedius nerve. RESULTS Correlation between traintime and outcome (Spearman's Rho) rose to 0.73 (p<0.001) when only patients without an identified intermedius nerve were considered, and fell to 0.43 (p<0.05) with the other patient group. This difference was statistically significant (p=0.036), was more prominent in the channels monitoring perioral facial muscles, and resulted from additional A-train activity in patients with an identifiable intermedius nerve. CONCLUSIONS A separate intermedius nerve may be more prone to manipulation, leading to A-train activity without clinical correlate, thus causing false positive monitoring results. SIGNIFICANCE For interpretation of the free-running EMG, the intermedius nerve needs to be taken into account as a confounder.
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Affiliation(s)
- Julian Prell
- Department of Neurosurgery, University of Halle, Ernst-Grube-Str. 40, 06097 Halle, Germany.
| | - Christian Strauss
- Department of Neurosurgery, University of Halle, Ernst-Grube-Str. 40, 06097 Halle, Germany
| | - Jens Rachinger
- Department of Neurosurgery, University of Halle, Ernst-Grube-Str. 40, 06097 Halle, Germany
| | - Christian Scheller
- Department of Neurosurgery, University of Halle, Ernst-Grube-Str. 40, 06097 Halle, Germany
| | - Alex Alfieri
- Department of Neurosurgery, University of Halle, Ernst-Grube-Str. 40, 06097 Halle, Germany
| | - Kirsten Herfurth
- Department of Neurosurgery, University of Halle, Ernst-Grube-Str. 40, 06097 Halle, Germany
| | - Stefan Rampp
- Department of Neurosurgery, University of Halle, Ernst-Grube-Str. 40, 06097 Halle, Germany
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Intraoperative Neurophysiological Monitoring in Neurosurgery: Moving the Debate from Evidence and Cost-Effectiveness to Education and Training. World Neurosurg 2015; 83:32-4. [DOI: 10.1016/j.wneu.2014.02.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2014] [Accepted: 02/10/2014] [Indexed: 11/19/2022]
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San-juan D, Barges-Coll J, Gómez Amador JL, Díaz MP, Alarcón AV, Escanio E, Anschel DJ, Padilla JAM, Barradas VA, Alcantar Aguilar MA, González-Aragón MF. Intraoperative monitoring of the abducens nerve in extended endonasal endoscopic approach: a pilot study technical report. J Electromyogr Kinesiol 2014; 24:558-64. [PMID: 24836215 DOI: 10.1016/j.jelekin.2014.04.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 03/15/2014] [Accepted: 04/01/2014] [Indexed: 10/25/2022] Open
Abstract
BACKGROUND To determine the reliability and usefulness of intraoperative monitoring of the abducens nerve during extended endonasal endoscopic skull base tumor resection. METHODS We performed abducens nerve intraoperative monitoring in 8 patients with giant clival lesions recording with needle electrodes sutured directly into the lateral rectus muscles of the eye to evaluate spontaneous electromyographic activity and triggered responses following stimulation of the abducens nerves. RESULTS A total of 16 abducens nerves were successfully recorded during endoscopic endonasal skull base surgeries. Neurotonic discharges were seen in two patients (12% [2/16] abducens nerves). Compound muscle action potentials of the abducens nerves were evoked with 0.1-4mA and maintained without changes during the neurosurgical procedures. No patient had new neurological deficits or ophthalmological complications post-surgery. CONCLUSIONS Intraoperative monitoring of the abducens nerve during the extended endonasal endoscopic approach to skull base tumors appears to be a safe method with the potential to prevent neural injury through the evaluation of neurotonic discharges and triggered responses.
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Affiliation(s)
- Daniel San-juan
- Neurophysiology Department, National Institute of Neurology and Neurosurgery, Mexico City, Mexico.
| | - Juan Barges-Coll
- Neurosurgery Department, National Institute of Neurology and Neurosurgery, Mexico City, Mexico
| | - Juan Luis Gómez Amador
- Neurosurgery Department, National Institute of Neurology and Neurosurgery, Mexico City, Mexico
| | - Marite Palma Díaz
- Neuro-otology Department, National Institute of Neurology and Neurosurgery, Mexico City, Mexico
| | - Alfredo Vega Alarcón
- Neuro-otology Department, National Institute of Neurology and Neurosurgery, Mexico City, Mexico
| | - Enrique Escanio
- Neuro-ophthalmology Service, National Institute of Neurology and Neurosurgery, Mexico City, Mexico
| | - David J Anschel
- Comprehensive Epilepsy Center of Long Island, St. Charles Hospital, Port Jefferson, NY, USA
| | | | - Victor Alcocer Barradas
- Neurosurgery Department, National Institute of Neurology and Neurosurgery, Mexico City, Mexico
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The Possibility of Clinical Trials in Neurophysiologic Intraoperative Monitoring. J Clin Neurophysiol 2014; 31:106-11. [DOI: 10.1097/wnp.0000000000000029] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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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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Baidya NB, Berhouma M, Ammirati M. Endoscope-assisted retrosigmoid resection of a medium size vestibular schwannoma tumor model: a cadaveric study. Clin Neurol Neurosurg 2014; 119:35-8. [PMID: 24635922 DOI: 10.1016/j.clineuro.2013.12.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 11/20/2013] [Accepted: 12/25/2013] [Indexed: 11/16/2022]
Abstract
OBJECTIVE To demonstrate a flexible endoscope assisted technique to perform microsurgical resection using a retrosigmoid approach of an artificial polymer tumor model that mimics a medium size (15-20mm diameter) vestibular schwannoma. METHODS Twelve bilateral retrosigmoid dissections were performed in 6 glutaraldehyde embalmed, colored silicone injected, adult cadaveric heads. Using a standard retrosigmoid approach, we first implanted the tumor model at the cerebellopontine angle (CPA) and then we resected the tumor under simultaneous endoscopic and microscopic visualizations. The resection was performed by first creating a corridor by removing the lower portion of the tumor and then by inserting through the same corridor the flexible endoscope mounted on a surgical instrument in order to accomplish early visualization of the VII-VIII complex. This early visualization of the VII-VIII complex made possible expeditious removal of the model with preservation of the VII-VIII complex. RESULTS We were able to successfully implant the artificial tumor in all the specimens. The post-tumor implantation CT scan confirmed the optimal CPA location of the model with its intra-porus extension. The exposure of the facial and the adjoining neuro-vascular structures was excellent during all stages of the surgical removal and was accomplished with minimal cerebellar retraction, under intermittent endoscopic-assisted control. Early visualization of the facial and vestibular cochlear nerves complex led to unhindered removal of the tumor model. CONCLUSIONS The endoscopic-assisted microsurgical removal of a tumor model simulating a medium size vestibular schwannoma was feasible in our tumor model study emulating real surgery. Visualization of the acousticofacial bundle at the early stage of the surgical removal should theoretically decrease the risk of its inadvertent injuries as well as facilitate complete removal of the tumor. Clinical studies to validate this laboratory study are necessary.
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Affiliation(s)
- Nishanta B Baidya
- Department of Neurological Surgery, The Ohio State University Wexner Medical Center, Columbus, USA
| | - Moncef Berhouma
- Department of Neurological Surgery, The Ohio State University Wexner Medical Center, Columbus, USA
| | - Mario Ammirati
- Department of Neurological Surgery, The Ohio State University Wexner Medical Center, Columbus, USA.
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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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Cosetti MK, Xu M, Rivera A, Jethanamest D, Kuhn MA, Beric A, Golfinos JG, Roland JT. Intraoperative Transcranial Motor-Evoked Potential Monitoring of the Facial Nerve during Cerebellopontine Angle Tumor Resection. J Neurol Surg B Skull Base 2013; 73:308-15. [PMID: 24083121 DOI: 10.1055/s-0032-1321507] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 03/28/2012] [Indexed: 10/28/2022] Open
Abstract
Objective To determine whether transcranial motor-evoked potential (TCMEP) monitoring of the facial nerve (FN) during cerebellopontine angle (CPA) tumor resection can predict both immediate and long-term postoperative FN function. Design Retrospective review. Setting Tertiary referral center. Main Outcome Measures DeltaTCMEP (final-initial) and immediate and long-term facial nerve function using House Brackmann (HB) rating scale. Results Intraoperative TCMEP data and immediate and follow-up FN outcome are reported for 52 patients undergoing CPA tumor resection. Patients with unsatisfactory facial outcome (HB >2) at follow-up had an average deltaTCMEP of 57 V, whereas those with HB I or II had a mean deltaTCMEP of 0.04 V (t = -2.6, p < 0.05.) Intraoperative deltaTCMEP did not differ significantly between groups with satisfactory (HB I, II) and unsatisfactory (HB > 2) facial function in the immediate postoperative period. Conclusion Intraoperative TCMEP of the facial nerve can be a valuable adjunct to conventional facial nerve electromyography during resection of tumors at the CPA. Intraoperative deltaTCMEP >57 V may be worrisome for long-term recovery of satisfactory facial nerve function.
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Affiliation(s)
- Maura K Cosetti
- Departments of Otolaryngology, New York University School of Medicine, New York, New York, United States
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Thirumala PD, Mohanraj SK, Habeych M, Wichman K, Chang YF, Gardner P, Snyderman C, Crammond DJ, Balzer J. Value of Free-Run Electromyographic Monitoring of Extraocular Cranial Nerves during Expanded Endonasal Surgery (EES) of the Skull Base. J Neurol Surg Rep 2013; 74:43-50. [PMID: 23943720 PMCID: PMC3713562 DOI: 10.1055/s-0033-1346975] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 03/05/2013] [Indexed: 12/04/2022] Open
Abstract
Objective To evaluate the value of free-run electromyography (f-EMG) monitoring of extraocular cranial nerves (EOCN) III, IV, and VI during expanded endonasal surgery (EES) of the skull base in reducing iatrogenic cranial nerve (CN) deficits. Design We retrospectively identified 200 patients out of 990 who had at least one EOCN monitored during EES. We further separated patients into groups according to the specific CN monitored. In each CN group, we classified patients who had significant (SG) f-EMG activity as Group I and those who did not as Group II. Results A total of 696 EOCNs were monitored. The number of muscles supplied by EOCNs that had SG f-EMG activity was 88, including CN III = 46, CN IV = 21, and CN VI = 21. There were two deficits involving CN VI in patients who had SG f-EMG activity during surgery. There were 14 deficits observed, including CN III = 3, CN IV = 2, and CN VI = 9 in patients who did not have SG f-EMG activity during surgery. Conclusions f-EMG monitoring of EOCN during EES can be useful in identifying the location of the nerve. It seems to have limited value in predicting postoperative neurological deficits. Future studies to evaluate the EMG of EOCN during EES need to be done with both f-EMG and triggered EMG.
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Affiliation(s)
- Parthasarathy D Thirumala
- Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA ; Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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Nakamae T, Tanaka N, Nakanishi K, Kamei N, Hamasaki T, Izumi B, Fujioka Y, Ohta R, Ochi M. Surgical treatment of high-grade dysplastic spondylolisthesis using intraoperative electrophysiological monitoring: report of two cases and review of the literature. EUROPEAN JOURNAL OF ORTHOPAEDIC SURGERY AND TRAUMATOLOGY 2013; 23 Suppl 1:S121-7. [DOI: 10.1007/s00590-013-1199-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 02/19/2013] [Indexed: 10/27/2022]
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Son BC, Lee SW, Kim S, Hong JT, Sung JH, Yang SH. Transzygomatic approach with intraoperative neuromonitoring for resection of middle cranial fossa tumors. J Neurol Surg B Skull Base 2013; 73:28-35. [PMID: 23372992 DOI: 10.1055/s-0032-1304561] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Accepted: 09/01/2011] [Indexed: 10/28/2022] Open
Abstract
The authors reviewed the surgical experience and operative technique in a series of 11 patients with middle fossa tumors who underwent surgery using the transzygomatic approach and intraoperative neuromonitoring (IOM) at a single institution. This approach was applied to trigeminal schwannomas (n = 3), cavernous angiomas (n = 3), sphenoid wing meningiomas (n = 3), a petroclival meningioma (n = 1), and a hemangiopericytoma (n = 1). An osteotomy of the zygoma, a low-positioned frontotemporal craniotomy, removal of the remaining squamous temporal bone, and extradural drilling of the sphenoid wing made a flat trajectory to the skull base. Total resection was achieved in 9 of 11 patients. Significant motor pathway damage can be avoided using a change in motor-evoked potentials as an early warning sign. Four patients experienced cranial nerve palsies postoperatively, even though free-running electromyography of cranial nerves showed normal responses during the surgical procedure. A simple transzygomatic approach provides a wide surgical corridor for accessing the cavernous sinus, petrous apex, and subtemporal regions. Knowledge of the middle fossa structures is essential for anatomic orientation and avoiding injuries to neurovascular structures, although a neuronavigation system and IOM helps orient neurosurgeons.
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Affiliation(s)
- Byung Chul Son
- Department of Neurosurgery, St. Vincent's Hospital, The Catholic University of Korea, Suwon, Korea
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Kircher ML, Kartush JM. Pitfalls in intraoperative nerve monitoring during vestibular schwannoma surgery. Neurosurg Focus 2013; 33:E5. [PMID: 22937856 DOI: 10.3171/2012.7.focus12196] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Despite the widespread acceptance of intraoperative neurophysiological monitoring in skull base surgery over the last 2 decades, surgeon training in the technical and interpretive aspects of nerve monitoring has been conspicuously lacking. Inadequate fundamental knowledge of neurophysiological monitoring may lead to misinterpretations and an inability to troubleshoot system errors. Some surgeons perform both the technical and interpretive aspects of monitoring themselves while others enjoin coworkers (surgical residents, nurses, anesthetists, or a separate monitoring service) to perform the technical portion. Regardless, the surgeon must have a thorough understanding to avoid potential medical and legal pitfalls because poor monitoring is worse than no monitoring. A structured curriculum and protocol in both the technical and interpretive aspects of monitoring is recommended for all personnel involved in the monitoring process. This paper details the technical, interpretive, and surgical correlates necessary for optimal intraoperative nerve monitoring during vestibular schwannoma surgery with an emphasis on electromyographic monitoring for facial and recurrent laryngeal nerves. Just as the American Society of Anesthesiologists' 1986 "Standards for Basic Anesthetic Monitoring" became a useful tool for both patients and anesthesiologists, impending guidelines in intraoperative neurophysiological monitoring should likewise become an important instrument for optimizing intraoperative neurophysiological monitoring.
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How Many Electromyography Channels Do We Need for Facial Nerve Monitoring? J Clin Neurophysiol 2012; 29:226-9. [DOI: 10.1097/wnp.0b013e318257cabc] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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Thirumala PD, Mohanraj SK, Habeych M, Wichman K, Chang YF, Gardner P, Snyderman C, Crammond DJ, Balzer J. Value of free-run electromyographic monitoring of lower cranial nerves in endoscopic endonasal approach to skull base surgeries. J Neurol Surg B Skull Base 2012; 73:236-44. [PMID: 23904999 DOI: 10.1055/s-0032-1312712] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Accepted: 01/27/2012] [Indexed: 10/28/2022] Open
Abstract
Objective The main objective of this study was to evaluate the value of free-run electromyography (f-EMG) monitoring of cranial nerves (CNs) VII, IX, X, XI, and XII in skull base surgeries performed using endoscopic endonasal approach (EEA) to reduce iatrogenic CN deficits. Design We retrospectively identified 73 patients out of 990 patients who had EEA in our institution who had at least one CN monitored. In each CN group, we classified patients who had significant (SG) f-EMG activity as group I and those who did not as group II. Results We monitored a total of 342 CNs. A total of 62 nerves had SG f-EMG activity including CN VII = 18, CN IX = 16, CN X = 13, CN XI = 5, and CN XII = 10. No nerve deficit was found in the nerves that had significant activity during procedure. A total of five nerve deficits including (CN IX = 1, CN X = 2, CN XII = 2) were observed in the group that did not display SG f-EMG activity during surgery. Conclusions f-EMG seems highly sensitive to surgical manipulations and in locating CNs. It seems to have limited value in predicting postoperative neurological deficits. Future studies to evaluate the EMG of lower CNs during EEA procedures need to be done with both f-EMG and triggered EMG.
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Affiliation(s)
- Parthasarathy D Thirumala
- Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, United States ; Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
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The Potential of Quantified Lower Cranial Nerve EMG for Monitoring of Anesthetic Depth. J Neurosurg Anesthesiol 2012; 24:139-45. [DOI: 10.1097/ana.0b013e3182401cef] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Hong RS, Kartush JM. Acoustic Neuroma Neurophysiologic Correlates:. Otolaryngol Clin North Am 2012; 45:291-306, vii-viii. [DOI: 10.1016/j.otc.2011.12.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Neurophysiologic Intraoperative Monitoring of Trigeminal and Facial Nerves. J Clin Neurophysiol 2011; 28:551-65. [DOI: 10.1097/wnp.0b013e318241de1a] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Kartush JM, Larouere MJ, Graham MD, Bouchard KR, Audet BV. Intraoperative cranial nerve monitoring during posterior skull base surgery. Skull Base 2011; 1:85-92. [PMID: 17170827 PMCID: PMC1656318 DOI: 10.1055/s-2008-1056986] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Intraoperative monitoring of neurophysiologic function is rapidly evolving as an important adjunct during skull base surgery to reduce the incidence of neurologic deficit. Facial nerve monitoring is an excellent model, since electrical and mechanical evoked potentials can be directly presented to the surgeon in real-time through an acoustic loudspeaker display. The lower cranial nerves may also be monitored using similar electromyographic techniques. Auditory system monitoring is more difficult due to the low amplitude response that requires averaging and filtering to extract the evoked potential. In conjunction with auditory monitoring, improved hearing preservation may be further enhanced by concomitant facial nerve monitoring, since the surgeon is alerted to traumatic manipulations that may affect both facial and cochlear nerves. Techniques and interpretative issues are presented to maximize the efficacy and safety of cranial nerve monitoring.
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Colletti V, Fiorino F. Continuous retrograde monitoring of the facial nerve during cerebellopontine angle surgery: normative data. Skull Base Surg 2011; 6:47-51. [PMID: 17170952 PMCID: PMC1656501 DOI: 10.1055/s-2008-1058912] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
An alternative technique for the continuous monitoring of the facial nerve, monopolar recording of facial nerve antidromic potentials (FNAPs), on 10 subjects undergoing retrosigmoid vestibular neurectomy for Meniere's disease is described. To elicit FNAPs bipolar electrical stimulation of the marginalis mandibulae was performed. Stimulus intensity ranged from 0 to 10 mA with a delivery rate of 7/second. Antidromic potentials were recorded with a silver wire monopolar electrode positioned intracranially on the proximal portion (root entry zone) of the acoustic-facial bundle. Bipolar recordings with two silver electrodes were also performed from different nerves in the cerebellopontine angle to define the specific origin of the action potentials. FNAP. amplitude increased as a function of stimulus intensity. The average latency was 3.35 milliseconds (range 3.0 to 3.7 ms). Action potentials recorded intracranially during electrical stimulation of the marginal nerve originated specifically from the facial nerve. FNAP recording is therefore a promising technique for the continuous intraoperative monitoring of the facial nerve during cerebellopontine angle surgery.
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Hester TO, Hasan A, McDonnell F, Valentino J, Jones R. Facial Nerve Monitoring under Neuromuscular Blockade. Skull Base Surg 2011; 5:69-72. [PMID: 17171179 PMCID: PMC1661820 DOI: 10.1055/s-2008-1058936] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The characteristics of facial nerve electromyography at various levels of neuromuscular blockade are unclear. Partial blockade is well known to facilitate anesthetic safety and management. However, the use of neuromuscular blockage in many skull base procedures is avoided to allow intraoperative facial nerve monitoring.We studied the influence of various levels of neuromuscular blockade on facial nerve stimulation in the New Zealand white rabbit. The facial nerve was exposed in the middle ear of six rabbits. Using electromyographic-type facial nerve monitor, we recorded the facial electromyography signals in these rabbits at increasing levels of vecuronium-induced neuromuscular blockade. All animals demonstrated reliable facial electromyography response at all levels of partial neuromuscular blockade (P < .02). Five of the six animals could be monitored throughout complete blockade. These results clearly demonstrate that rabbit facial electromyography monitoring is possible under neuromuscular blockade. The effect of neuromuscular blockers on facial electromyography monitoring deserves further study, as partial blockade would greatly facilitate the management of anesthesia in otologic, neurotologic, and skull base surgery.
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Mishler ET, Smith PG. Technical aspects of intraoperative monitoring of lower cranial nerve function. Skull Base Surg 2011; 5:245-50. [PMID: 17170965 PMCID: PMC1656530 DOI: 10.1055/s-2008-1058922] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The efficacy of monitoring facial nerve activity in decreasing long-term morbidity has promoted an interest in monitoring other at-risk cranial nerves during procedures that involve manipulation of the basal cranial nerves. This presentation details practical techniques for monitoring the lower cranial nerves, which have been experientially developed over the past 9 years. Emphasis is placed on the selection of electrodes and procedural changes required for reliable and safe stimulation of the basal cranial nerves. Either paired hook-wire or tethered needle electrodes can be used for monitoring glossopharyageal, accessory, and hypoglossal nerve function. Several options for monitoring vagus nerve function are discussed. Of these, the transoral placement of paired hook-wire electrodes remains the most reliable, cost-effective, and least morbid technique. Electrical stimulation of the glossopharyngeal and vagus nerves carries the risk of unanticipated, potentially irreversible disturbances in cardiovascular function. Guidelines for type and optimal placement of stimulating electrodes and recommended intensity levels to prevent unfavorable reactions are presented.
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Colletti V, Fiorino FG. Continuous retrograde monitoring of the facial nerve: preliminary experience during acoustic neuroma surgery. Skull Base Surg 2011; 6:77-81. [PMID: 17170981 PMCID: PMC1656583 DOI: 10.1055/s-2008-1058648] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Continuous electromyographical (EMG) monitoring of the facial nerve is widely used during acoustic tumor surgery. Mechanical stimulation of the facial nerve is capable of eliciting synchronous and asynchronous EMG responses alerting the surgeon to damaging maneuvers performed on the nerve. Mechanical stimulation, however, elicits EMG responses only when the nerve has been injured by the underlying pathology or previous surgical maneuvers, and the technique is sensitive to administration of muscular blockers. In addition, EMG is unable to furnish quantitative information about the damage. The present paper illustrates an alternative technique for intraoperative facial nerve monitoring, that is, the recording of facial nerve antidromic potentials (FNAPs).Eleven subjects operated on by acoustic neuroma surgery via a retrosigmoid approach (tumor sizes ranging from 12 to 28 mm) participated in the investigation. Bipolar electrical stimulation of the marginalis mandibulae was performed to elicit FNAPs. Stimulus intensity ranged from 2 to 6 mA with a delivery rate of 7/second. A silver-wire electrode positioned on the proximal portion of the acoustic-facial bundle was used to record action potentials. Changes in latency and amplitude of FNAPs were analyzed as a function of the main surgical steps. FNAP monitoring provided quantitative real-time information about damaging maneuvers performed on the nerve and allowed prediction of postoperative facial function.
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Sughrue ME, Yang I, Rutkowski MJ, Aranda D, Parsa AT. Preservation of facial nerve function after resection of vestibular schwannoma. Br J Neurosurg 2011; 24:666-71. [PMID: 21070151 DOI: 10.3109/02688697.2010.520761] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Most data regarding facial nerve function in patients undergoing microsurgical resection of vestibular schwannomas predominantly include series performed at a single institution. In an effort to minimise individual surgeon or institutional bias, we performed an analysis of the published literature on facial nerve outcomes following microsurgical resection of vestibular schwannomas. The objective of this study was to provide a comprehensive assessment of reported outcomes for facial nerve preservation after VS surgery. MATERIALS AND METHODS We identified a total of 296 studies involving over 25,000 patients that included outcome data for facial nerve function of vestibular schwannoma patients treated surgically. Data regarding surgical approach, tumour size, patient age, and use of intra-operative monitoring were extracted and correlated with facial nerve function after surgery. Patients with preoperative facial nerve dysfunction (House-Brackmann score 3 or higher) were excluded and 'facial nerve preservation' was defined as grade I or II House-Brackmann function at last follow-up visit. RESULTS A total of 79 articles reporting on 11,873 patients met our inclusion criteria contributing to our analysis. Patients treated with the middle cranial fossa approach had a trend towards higher overall facial nerve preservation rate (85%), compared to the translabyrinthine approach (81%, p = 0.07) , and did statistically better than the retrosigmoid approach (78%, p < 0.0001). Patients with an average tumour size <20 mm had significantly improved facial nerve preservation rates, compared to larger tumours (90% vs. 67%, p < 0.0001). Patients under 65 years of age had a lower facial nerve preservation rate (71% vs. 84%, p < 0.001). Finally, the use of intra-operative monitoring improved the facial nerve preservation rate (76% vs. 71%, p < 0.001). CONCLUSION Factors that appear to be associated with facial nerve preservation after microsurgical resection of a vestibular schwannoma include tumour size <20 mm, use of the middle fossa approach and use of neuromonitoring during surgery. These data provide a summary assessment of the published literature regarding facial nerve preservation after microsurgical resection of vestibular schwannoma.
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Affiliation(s)
- Michael E Sughrue
- Department of Neurological Surgery, University of California at San Francisco, 505 Parnassus Ave., San Francisco, CA 94143, USA
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Amano M, Kohno M, Nagata O, Taniguchi M, Sora S, Sato H. Intraoperative continuous monitoring of evoked facial nerve electromyograms in acoustic neuroma surgery. Acta Neurochir (Wien) 2011; 153:1059-67; discussion 1067. [PMID: 21340712 DOI: 10.1007/s00701-010-0937-6] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Accepted: 12/29/2010] [Indexed: 11/29/2022]
Abstract
BACKGROUND Preservation of facial nerve function is one of the most important goals in acoustic neuroma surgery. We have been using intraoperative continuous monitoring of evoked facial nerve electromyograms (EMGs) since 1997 in acoustic neuroma surgery. We therefore investigated surgically treated patients to clarify the usefulness of this monitoring, and to determine safety criteria for preserving facial nerve function. METHODS This intraoperative continuous monitoring of evoked facial nerve EMG is a method for checking the EMG evoked by continuous direct electrical stimulation of the facial nerve during tumor excision. The greatest advantage of this method is the ability to identify changes in EMG in real time. We retrospectively investigated 216 patients with surgically treated acoustic neuroma to identify correlations between parameters in this monitoring and postoperative facial nerve function immediately and 1 year after surgery. RESULTS In these patients, the functional preservation rate of the facial nerve (House and Brackmann grade 1 or 2 at 1 year after surgery) was 98.6% with a 98.2% mean tumor resection rate. Amplitude preservation ratio correlated significantly with facial nerve function both immediately and 1 year after surgery. To avoid severe facial nerve palsy, a warning criterion of amplitude preservation ratio >50% appears useful. CONCLUSIONS Postoperative course of facial nerve function appears predictable using intraoperative continuous monitoring of evoked facial nerve EMGs. This monitoring is useful to increase the tumor excision rate while avoiding severe postoperative facial nerve palsy in acoustic neuroma surgery.
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Affiliation(s)
- Midori Amano
- Department of Neurosurgery and Stroke Center, Tokyo Metropolitan Police Hospital, 4-22-1, Nakano, Nakano-Ku, Tokyo, 164-0001, Japan
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Foroughi M, Pitkäniemi J, Nannapaneni R, Nath F. Excision of vestibular schwannomas – is there a learning curve and how best to demonstrate it? Br J Neurosurg 2010; 24:547-54. [DOI: 10.3109/02688697.2010.503815] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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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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Youssef AS, Downes AE. Intraoperative neurophysiological monitoring in vestibular schwannoma surgery: advances and clinical implications. Neurosurg Focus 2009; 27:E9. [PMID: 19795957 DOI: 10.3171/2009.8.focus09144] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Intraoperative neurophysiological monitoring has become an integral part of vestibular schwannoma surgery. The aim of this article was to review the different techniques of intraoperative neurophysiological monitoring in vestibular schwannoma surgery, identify the clinical impact of certain pathognomonic patterns on postoperative outcomes of facial nerve function and hearing preservation, and highlight the role of postoperative medications in improving delayed cranial nerve dysfunction in the different reported series. METHODS The authors performed a review of the literature regarding intraoperative monitoring in acoustic/vestibular schwannoma surgery. The different clinical series representing different monitoring techniques were reviewed. All the data from clinical series were analyzed in a comprehensive and comparative model. RESULTS Intraoperative brainstem auditory evoked potential monitoring, direct cochlear nerve action potential monitoring, and facial nerve electromyography are the main tools used to assess the functional integrity of an anatomically intact cranial nerve. The identification of pathognomonic brainstem auditory evoked potential and electromyography patterns has been correlated with postoperative functional outcome. Recently, perioperative administration of intravenous hydroxyethyl starch and nimodipine as vasoactive and neuroprotective agents was shown to improve vestibular schwannoma functional outcome in few reported studies. CONCLUSIONS Recent advances in electrophysiological technology have considerably contributed to improvement in functional outcome of vestibular neuroma surgery in terms of hearing preservation and facial nerve paresis. Perioperative intravenous nimodipine and hydroxyethyl starch may be valuable additions to surgery.
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Affiliation(s)
- A Samy Youssef
- Department of Neurosurgery, University of South Florida, Tampa, Florida 33606, USA.
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Intraoperative multimodality monitoring in adult spinal deformity: analysis of a prospective series of one hundred two cases with independent evaluation. Spine (Phila Pa 1976) 2009; 34:1504-12. [PMID: 19483667 DOI: 10.1097/brs.0b013e3181a87b66] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN A retrospective analysis of prospectively collected data of 102 consecutive adult patients who underwent intraoperative neurophysiological monitoring (IOM) during spinal deformity corrective surgery. OBJECTIVE To report the sensitivity and specificity of combined IOM in this study population using the postoperative neurologic examination as the "gold standard." SUMMARY OF BACKGROUND DATA IOM is recommended during corrective spinal surgery and has been widely used in the pediatric deformity population. However, there are limited data describing the application of IOM in adults undergoing spinal deformity corrective surgery. METHODS The study group consisted of 102 patients undergoing spinal deformity corrective surgery between 2001 and 2004. Patients were monitored using at least 2 or more electrophysiological methods including somatosensory-evoked potentials (SSEP), motor-evoked potentials (MEP), and electromyography (EMG). RESULTS The mean age of patients was 41.5 years (+/-17). The majority of the operative procedures involved instrumented fusion from thoracic to lumbar/sacral spine (n = 55), thoracic-pelvis fusion (n = 26), and a combined total of 32 osteotomies (including 25 pedicle subtraction osteotomies and 7 Smith-Peterson osteotomies). SSEPs were recorded successfully in 101 (99%), EMGs in 89 of 102 (87%), and MEPs in 12 of 16 (75%). Five cases were true positives (4.95%), and these were all detected by combined monitoring (2-SSEP, 2-EMG, 1-MEP). There were no false positives with SSEPs, but EMG resulted in 30 of 89 (34%) false positives. There were 4 false negatives with SSEPs, which reduced its sensitivity to 33%. There was 1 false negative with EMG, and 0 with MEPs. When these results were collated, the overall sensitivity of combined multimodality IOM in this adult deformity series was 100%, specificity 84.3%, PPV 13.9%, and NPV 97%. The combined sensitivity in the osteotomy group (n = 32) was 67%, specificity 98%, PPV 80%, and NPV 96%. In comparison, there were no IOM abnormalities in those patients who had in situ/minor corrective procedures (n = 18; largely adult degenerative scoliosis). CONCLUSION Multimodality IOM of spinal cord sensory and motor function during surgical correction of adult spinal deformity is feasible and provides useful neurophysiological data with an overall sensitivity of 100% and a specificity of 84.3% (67% and 98%, respectively in patients undergoing major deformity correction).
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Spontaneous Electromyographic Activity During Microvascular Decompression in Trigeminal Neuralgia. J Clin Neurophysiol 2008; 25:225-32. [DOI: 10.1097/wnp.0b013e31817f368f] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Teudt IU, Nevel AE, Izzo AD, Walsh JT, Richter CP. Optical stimulation of the facial nerve: a new monitoring technique? Laryngoscope 2007; 117:1641-7. [PMID: 17607145 PMCID: PMC3471076 DOI: 10.1097/mlg.0b013e318074ec00] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
OBJECTIVES/ HYPOTHESIS One sequela of skull base surgery is iatrogenic damage to cranial nerves, which can be prevented if the nerve is identified. Devices that stimulate nerves with electric current assist in nerve identification. Contemporary devices have two main limitations: 1) the physical contact of the stimulating electrode and (2) the spread of the current through the tissue. In contrast to electrical stimulation, pulsed infrared optical radiation can be used to safely and selectively stimulate neural tissue and might be valuable for screening. METHODS The gerbil facial nerve was exposed to 250 microsecond pulses of 2.12 microm radiation delivered via a 600-microm-diameter optical fiber at a repetition rate of 2 Hz. With use of 27 GA, 12-mm intradermal electrodes, muscle action potentials were recorded. Nerve samples were examined for possible tissue damage. RESULTS Eight facial nerves were stimulated with radiant exposures between 0.71 and 1.77 J/cm, resulting in compound muscle action potentials (CmAPs) that were simultaneously measured at the m. orbicularis oculi, m. levator nasolabialis, and m. orbicularis oris. Resulting CmAP amplitudes were 0.3 to 0.4 mV, 0.15 to 1.4 mV, and 0.3 to 2.3 mV, respectively, depending on the radial location of the optical fiber and the radiant exposure. Individual nerve branches were also stimulated, resulting in CmAP amplitudes between 0.2 and 1.6 mV. Histology revealed tissue damage at radiant exposures of 2.2 J/cm but no apparent damage at radiant exposures of 2.0 J/cm. CONCLUSIONS The experiments showed that selective muscle action potentials can be evoked optically in the gerbil facial nerve without direct physical contact.
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Affiliation(s)
- Ingo Ulrik Teudt
- Department of Otolaryngology-Head and Neck Surgery, Northwestern University, Feinberg School of Medicine, Chicago, Illinois 60611-3008, USA
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