The Initial Use of Free-running Electromyography to Detect Early Motor Tract Injury during Resection of Intramedullary Spinal Cord Lesions

2005 ◽  
Vol 56 (suppl_4) ◽  
pp. ONS-299-ONS-314 ◽  
Author(s):  
Stanley A. Skinner ◽  
Mahmoud Nagib ◽  
Thomas A. Bergman ◽  
Robert E. Maxwell ◽  
Gaspar Msangi
Keyword(s):  
Spinal Cord ◽  
Evoked Potentials ◽  
Motor Evoked Potentials ◽  
False Negative ◽  
Neurological Deficits ◽  
Motor Deficit ◽  
Spinal Cord Lesions ◽  
Blood Pressure Elevation ◽  
Intramedullary Spinal Cord ◽  
Free Running

Abstract OBJECTIVE: The resection of intramedullary spinal cord lesions (ISCLs) can be complicated by neurological deficits. Neuromonitoring has been used to reduce intraoperative risk. We have used somatosensory evoked potentials (SEPs) and muscle-derived transcranial electrical motor evoked potentials (myogenic TCE-MEPs) to monitor ISCL removal. We report our retrospective experience with the addition of free-running electromyography (EMG). METHODS: Thirteen patients underwent 14 monitored ISCL excisions. Anesthesia was maintained with minimal inhalant to reduce motoneuron suppression and enhance the myogenic TCE-MEPs. Free-running EMG was examined in the four limbs for evidence of abnormal bursts, prolonged tonic discharge, or sudden electrical silence. Warning of an electromyographic abnormality or myogenic TCE-MEP loss prompted interventions, including blood pressure elevation, a pause in surgery, a wake-up test, or termination of surgery. Pre- and postoperative neurological examinations determined the incidence of new deficits. RESULTS: The combined use of free-running EMG and myogenic TCE-MEPs detected all eight patients with a new motor deficit after surgery; there was one false-positive report. In three of the eight true-positive cases, an electromyographic abnormality immediately anticipated loss of the myogenic TCE-MEPs. Two patients with abnormal EMGs but unchanged myogenic TCE-MEPs experienced mild postoperative worsening of motor deficits; myogenic TCE-MEPs alone would have generated false-negative reports in these cases. CONCLUSION: During resection of ISCLs, free-running EMG can supplement motor tract monitoring by TCE-MEPs. Segmental and suprasegmental elicitation of neurotonic discharges can be observed in four-limb EMG. Abnormal electromyographic bursts, tonic discharge, or abrupt electromyographic silence may anticipate myogenic TCE-MEP loss and predict a postoperative motor deficit.

Spinal Cord Mapping as an Adjunct for Resection of Intramedullary Tumors: Surgical Technique with Case Illustrations

Neurosurgery ◽  
2002 ◽  
Vol 51 (5) ◽  
pp. 1199-1207 ◽  
Author(s):  
Alfredo Quinones-Hinojosa ◽  
Mittul Gulati ◽  
Russell Lyon ◽  
Nalin Gupta ◽  
Charles Yingling
Keyword(s):  
Spinal Cord ◽  
Evoked Potentials ◽  
Motor Evoked Potentials ◽  
Cervical Spinal Cord ◽  
Tumor Resection ◽  
Neurological Deficits ◽  
Electromyographic Activity ◽  
Intramedullary Spinal Cord ◽  
Motor Tracts ◽  
Stimulation Of

Abstract OBJECTIVE Resection of intramedullary spinal cord tumors may result in transient or permanent neurological deficits. Intraoperative somatosensory evoked potentials (SSEPs) and motor evoked potentials are commonly used to limit complications. We used both antidromically elicited SSEPs for planning the myelotomy site and direct mapping of spinal cord tracts during tumor resection to reduce the risk of neurological deficits and increase the extent of tumor resection. METHODS In two patients, 3 and 12 years of age, with tumors of the thoracic and cervical spinal cord, respectively, antidromically elicited SSEPs were evoked by stimulation of the dorsal columns and were recorded with subdermal electrodes placed at the medial malleoli bilaterally. Intramedullary spinal cord mapping was performed by stimulating the resection cavity with a handheld Ojemann stimulator (Radionics, Burlington, MA). In addition to visual observation, subdermal needle electrodes inserted into the abductor pollicis brevis-flexor digiti minimi manus, tibialis anterior-gastrocnemius, and abductor halluces-abductor digiti minimi pedis muscles bilaterally recorded responses that identified motor pathways. RESULTS The midline of the spinal cord was anatomically identified by visualizing branches of the dorsal medullary vein penetrating the median sulcus. Antidromic responses were obtained by stimulation at 1-mm intervals on either side of the midline, and the region where no response was elicited was selected for the myelotomy. The anatomic and electrical midlines did not precisely overlap. Stimulation of abnormal tissue within the tumor did not elicit electromyographic activity. Approaching the periphery of the tumor, stimulation at 1 mA elicited an electromyographic response before normal spinal cord was visualized. Restimulation at lower currents by use of 0.25-mA increments identified the descending motor tracts adjacent to the tumor. After tumor resection, the tracts were restimulated to confirm functional integrity. Both patients were discharged within 2 weeks of surgery with minimal neurological deficits. CONCLUSION Antidromically elicited SSEPs were important in determining the midline of a distorted cord for placement of the myelotomy incision. Mapping spinal cord motor tracts with direct spinal cord stimulation and electromyographic recording facilitated the extent of surgical resection.

The Role of Motor Evoked Potentials during Surgery for Intramedullary Spinal Cord Tumors

Neurosurgery ◽  
1997 ◽  
Vol 41 (6) ◽  
pp. 1327-1336 ◽  
Author(s):  
Nobu Morota ◽  
Vedran Deletis ◽  
Shlomi Constantini ◽  
Markus Kofler ◽  
Henry Cohen ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Evoked Potentials ◽  
Motor Evoked Potentials ◽  
Spinal Cord Tumors ◽  
Intramedullary Spinal Cord

Transvertebral Transposition of the Spinal Cord for Recovery of Motor Evoked Potentials and Somatosensory Evoked Potentials After Acute Paraplegia During Kyphoscoliosis Surgery: Technique Note, Case Reports and Literature Review

2020 ◽  
Author(s):  
Chao Chen ◽  
Jing Li ◽  
Bingjin Wang ◽  
Lingwei Zhu ◽  
Yong Gao ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Evoked Potentials ◽  
Somatosensory Evoked Potentials ◽  
Motor Evoked Potentials ◽  
Case Reports ◽  
Deformity Correction ◽  
Neurological Deficits ◽  
Intraoperative Neurophysiological Monitoring ◽  
Neurophysiological Monitoring ◽  
Acute Paraplegia

Abstract Background: Neurological impairment during spinal deformity surgery was the most serious complication. When confronting intraoperative neurophysiological monitoring alerts, various surgical management methods such as the release of implants and decompression of the spinal cord are always performed. Transvertebral transposition of the spinal cord is rarely performed, and its role in the management of acute paraplegia is seldom reported.Methods: The authors present two patients with kyphoscoliosis experienced intraoperatively or postoperatively neurological deficits and abnormal neurological monitoring was detected during correction surgery. Acute paraplegia was confirmed by a wake-up test. Subsequent spinal cord transposition was performed. Intraoperative neurophysiological monitoring motor evoked potentials (MEP) and somatosensory evoked potentials (SEP) was performed to detect the changes during the process.Results: After transvertebral transposition of the spinal cord, the MEPs and SEPs were significantly improved in both patients during surgery. The spinal cord function was restored postoperatively and recovered to normal at the final follow-up in two patients. Conclusions： This case demonstrated that instead of decreasing the correction ratio of kyphoscoliosis, transvertebral transposition of the spinal cord under intraoperative neurophysiological monitoring could be an effective therapeutic strategy for acute spinal cord dysfunction caused by deformity correction surgeries.

Predictive Value and Safety of Intraoperative Neurophysiological Monitoring With Motor Evoked Potentials in Glioma Surgery

Neurosurgery ◽  
2011 ◽  
Vol 70 (5) ◽  
pp. 1060-1071 ◽  
Author(s):  
Sandro M. Krieg ◽  
Ehab Shiban ◽  
Doris Droese ◽  
Jens Gempt ◽  
Niels Buchmann ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Predictive Value ◽  
Motor System ◽  
Motor Evoked Potentials ◽  
False Negative ◽  
Motor Deficit ◽  
Neurophysiological Monitoring ◽  
Glioma Surgery ◽  
Supratentorial Gliomas

Abstract BACKGROUND: Resection of gliomas in or adjacent to the motor system is widely performed with intraoperative neuromonitoring (IOM). Despite the fact that data on the safety of IOM are available, the significance and predictive value of the procedure are still under discussion. Moreover, cases of false-negative monitoring affect the surgeon's confidence in IOM. OBJECTIVE: To examine cases of false-negative IOM to reveal structural explanations. METHODS: Between 2007 and 2010, we resected 115 consecutive supratentorial gliomas in or close to eloquent motor areas using direct cortical stimulation for monitoring of motor evoked potentials (MEPs). The monitoring data were reviewed and related to new postoperative motor deficit and postoperative imaging. Clinical outcomes were assessed during follow-up. RESULTS: Monitoring of MEPs was successful in 112 cases (97.4%). Postoperatively, 30.3% of patients had a new motor deficit, which remained permanent in 12.5%. Progression-free follow-up was 9.7 months (range, 2 weeks-40.6 months). In 65.2% of all cases, MEPs were stable throughout the operation, but 8.9% showed a new temporary motor deficit, whereas 4.5% (5 patients) presented with permanently deteriorated motor function representing false-negative monitoring at first glance. However, these cases were caused by secondary hemorrhage, ischemia, or resection of the supplementary motor area. CONCLUSION: Continuous MEP monitoring provides reliable monitoring of the motor system, influences the course of operation in some cases, and has to be regarded as the standard for IOM of the motor system. In our series, we found no false-negative MEP results.

Dorsal Column Mapping via Phase Reversal Method

Neurosurgery ◽  
2014 ◽  
Vol 74 (4) ◽  
pp. 437-446 ◽  
Author(s):  
Dinesh Nair ◽  
Vishakhadatta M. Kumaraswamy ◽  
Diana Braver ◽  
Ronan D. Kilbride ◽  
Lawrence F. Borges ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Evoked Potentials ◽  
Somatosensory Evoked Potentials ◽  
Spinal Cord Tumor ◽  
Tumor Resection ◽  
Dorsal Column ◽  
Neurological Deficits ◽  
Reliable Technique ◽  
Intramedullary Spinal Cord ◽  
Phase Reversal

ABSTRACT BACKGROUND: Safe resection of intramedullary spinal cord tumors can be challenging, because they often alter the cord anatomy. Identification of neurophysiologically viable dorsal columns (DCs) and of neurophysiologically inert tissue, eg, median raphe (MR), as a safe incision site is crucial for avoiding postoperative neurological deficits. We present our experience with and improvements made to our previously described technique of DC mapping, successfully applied in a series of 12 cases. OBJECTIVE: To describe a new, safe, and reliable technique for intraoperative DC mapping. METHODS: The right and left DCs were stimulated by using a bipolar electric stimulator and the triggered somatosensory evoked potentials recorded from the scalp. Phase reversal and amplitude changes of somatosensory evoked potentials were used to neurophysiologically identify the laterality of DCs, the inert MR, as well as other safe incision sites. RESULTS: The MR location was neurophysiologically confirmed in all patients in whom this structure was first visually identified as well as in those in whom it was not, with 1 exception. DCs were identified in all patients, regardless of whether they could be visually identified. In 3 cases, negative mapping with the use of this method enabled the surgeon to reliably identify additional inert tissue for incision. None of the patients had postoperative worsening of the DC function. CONCLUSION: Our revised technique is safe and reliable, and it can be easily incorporated into routine intramedullary spinal cord tumor resection. It provides crucial information to the neurosurgeon to prevent postoperative neurological deficits.

scholarly journals Intraoperative neurophysiological monitoring during resection of infratentorial lesions: the surgeon's view

2017 ◽  
Vol 126 (1) ◽  
pp. 281-288 ◽  
Author(s):  
Philipp J. Slotty ◽  
Amr Abdulazim ◽  
Kunihiko Kodama ◽  
Mani Javadi ◽  
Daniel Hänggi ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Posterior Fossa ◽  
Auditory Evoked Potentials ◽  
Motor Evoked Potentials ◽  
Neurological Deficits ◽  
Neurophysiological Monitoring ◽  
Posterior Fossa Surgery ◽  
Lesion Location ◽  
Crucial Information ◽  
Free Running

OBJECTIVE Methods of choice for neurophysiological intraoperative monitoring (IOM) within the infratentorial compartment mostly include early brainstem auditory evoked potentials, free-running electromyography, and direct cranial nerve (CN) stimulation. Long-tract monitoring with somatosensory evoked potentials (SEPs) and motor evoked potentials (MEPs) is rarely used. This study investigated the incidence of IOM alterations during posterior fossa surgery stratified for lesion location. METHODS Standardized CN and SEP/MEP IOM was performed in 305 patients being treated for various posterior fossa pathologies. The IOM data were correlated with lesion locations and histopathological types as well as other possible confounding factors. RESULTS Alterations in IOM were observed in 158 of 305 cases (51.8%) (CN IOM alterations in 130 of 305 [42.6%], SEP/MEP IOM alterations in 43 of 305 [14.0%]). In 15 cases (4.9%), simultaneous changes in long tracts and CNs were observed. The IOM alterations were followed by neurological sequelae in 98 of 305 cases (32.1%); 62% of IOM alterations resulted in neurological deficits. Sensitivity and specificity for detection of CN deficits were 98% and 77%, respectively, and 95% and 85%, respectively, for long-tract deficits. Regarding location, brainstem and petroclival lesions were closely associated with concurrent CN IOM and SEP/MEP alterations. CONCLUSIONS The incidence of IOM alterations during surgery in the posterior fossa varied widely between different lesion locations and histopathological types. This analysis provides crucial information on the necessity of IOM in different surgical settings. Because MEP/SEP and CN IOM alterations were commonly observed during posterior fossa surgery, the authors recommend the simultaneous use of both modalities based on lesion location.

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