False-Positive and False-Negative Results of Motor Evoked Potential Monitoring During Surgery for Intramedullary Spinal Cord Tumors.

BACKGROUND Motor evoked potential (MEP) recording is used as a method to monitor integrity of the motor system during surgery for intramedullary tumors (IMTs). Reliable sensitivity of the monitoring in predicting functional deterioration has been reported. However, we observed false positives and false negatives in our experience of 250 surgeries of IMTs. OBJECTIVE To delineate specificity and sensitivity of MEP monitoring and to elucidate its limitations and usefulness. METHODS From 2008 to 2011, 58 patients underwent 62 surgeries for IMTs. MEP monitoring was performed in 59 operations using transcranial electrical stimulation. Correlation with changes in muscle strength and locomotion was analyzed. A group undergoing clipping for unruptured aneurysms was compared for elicitation of MEP. RESULTS Of 212 muscles monitored in the 59 operations, MEP was recorded in 150 (71%). Positive MEP warnings, defined as amplitude decrease below 20% of the initial level, occurred in 37 muscles, but 22 of these (59%) did not have postoperative weakness (false positive). Positive predictive value was limited to 0.41. Of 113 muscles with no MEP warnings, 8 muscles developed postoperative weakness (false negative, 7%). Negative predictive value was 0.93. MEP responses were not elicited in 58 muscles (27%). By contrast, during clipping for unruptured aneurysms, MEP was recorded in 216 of 222 muscles (96%). CONCLUSION MEP monitoring has a limitation in predicting postoperative weakness in surgery for IMTs. False-positive and false-negative indices were abundant, with sensitivity and specificity of 0.65 and 0.83 in predicting postoperative weakness.

[1]  Y. Matsuyama,et al.  The Cutoff Amplitude of Transcranial Motor Evoked Potentials for Transient Postoperative Motor Deficits in Intramedullary Spinal Cord Tumor Surgery , 2014, Spine.

[2]  J. Klekamp.  Treatment of intramedullary tumors: analysis of surgical morbidity and long-term results. , 2013, Journal of neurosurgery. Spine.

[3]  G. Faccani,et al.  Relevance of intraoperative D wave in spine and spinal cord surgeries , 2013, European Spine Journal.

[4]  V. Rajshekhar,et al.  Factors predicting the feasibility of monitoring lower-limb muscle motor evoked potentials in patients undergoing excision of spinal cord tumors. , 2011, Journal of neurosurgery. Spine.

[5]  A. Friedman,et al.  Impact of Tumor Histology on Resectability and Neurological Outcome in Primary Intramedullary Spinal Cord Tumors: A Single-Center Experience With 102 Patients , 2011, Neurosurgery.

[6]  C. Shaffrey,et al.  Intraoperative Electrophysiological Monitoring in Spine Surgery , 2010, Spine.

[7]  Michael O'Brien.  Aids to the Examination of the Peripheral Nervous System , 2010 .

[8]  John H. Martin,et al.  Activity-Dependent Codevelopment of the Corticospinal System and Target Interneurons in the Cervical Spinal Cord , 2009, The Journal of Neuroscience.

[9]  M. Kawaguchi,et al.  Evaluation of the applicability of sevoflurane during post-tetanic myogenic motor evoked potential monitoring in patients undergoing spinal surgery , 2009, Journal of Anesthesia.

[10]  Y. Matsuyama,et al.  Surgical results of intramedullary spinal cord tumor with spinal cord monitoring to guide extent of resection. , 2009, Journal of neurosurgery. Spine.

[11]  S. Hyun,et al.  Combined motor and somatosensory evoked potential monitoring for intramedullary spinal cord tumor surgery: correlation of clinical and neurophysiological data in 17 consecutive procedures , 2009, British journal of neurosurgery.

[12]  Y. Iwasaki,et al.  Long-term follow-up results in patients with cervical disk disease treated by cervical anterior fusion using titanium cage implants. , 2008, Neurologia medico-chirurgica.

[13]  A. Bucciero,et al.  Peek cage-assisted anterior cervical discectomy and fusion at four levels: clinical and radiographic results. , 2008, Journal of neurosurgical sciences.

[14]  D. Sterio,et al.  Success Rate of Motor Evoked Potentials for Intraoperative Neurophysiologic Monitoring: Effects of Age, Lesion Location, and Preoperative Neurologic Deficits , 2007, Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society.

[15]  P. Lanteri,et al.  Motor Evoked Potential Monitoring Improves Outcome after Surgery for Intramedullary Spinal Cord Tumors: A Historical Control Study , 2006, Neurosurgery.

[16]  M. McDermott,et al.  Changes in Transcranial Motor Evoked Potentials during Intramedullary Spinal Cord Tumor Resection Correlate with Postoperative Motor Function , 2005, Neurosurgery.

[17]  M. Seyal,et al.  Mechanisms of Signal Change During Intraoperative Somatosensory Evoked Potential Monitoring of the Spinal Cord , 2002, Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society.

[18]  V. Deletis,et al.  Motor-evoked potential monitoring for intramedullary spinal cord tumor surgery: correlation of clinical and neurophysiological data in a series of 100 consecutive procedures. , 1998, Neurosurgical focus.

[19]  W Harris,et al.  "Threshold-level" multipulse transcranial electrical stimulation of motor cortex for intraoperative monitoring of spinal motor tracts: description of method and comparison to somatosensory evoked potential monitoring. , 1998, Journal of neurosurgery.

[20]  H. Abe,et al.  Magnetic resonance imaging findings in ossification of the posterior longitudinal ligament of the cervical spine. , 1998, Journal of neurosurgery.

[21]  M. Kofler,et al.  The role of motor evoked potentials during surgery for intramedullary spinal cord tumors. , 1997, Neurosurgery.

[22]  V Deletis,et al.  Intraoperative spinal cord monitoring for intramedullary surgery: an essential adjunct. , 1997, Pediatric neurosurgery.

[23]  P. Nathan,et al.  Vestibulospinal, reticulospinal and descending propriospinal nerve fibres in man. , 1996, Brain : a journal of neurology.

[24]  M. Weidenbaum,et al.  Intraoperative monitoring of motor evoked potentials , 1996, Neurology.

[25]  J. Schramm,et al.  Transcranial high-frequency repetitive electrical stimulation for recording myogenic motor evoked potentials with the patient under general anesthesia. , 1996, Neurosurgery.

[26]  L. Kearse,et al.  Loss of intraoperative somatosensory evoked potentials during intramedullary spinal cord injury predicts postoperative neurologic deficits in motor function , 1993 .

[27]  Makoto Taniguchi,et al.  Modification of cortical stimulation for motor evoked potentials under general anesthesia: technical description. , 1993, Neurosurgery.

[28]  P. Mccormick,et al.  Intramedullary ependymoma of the spinal cord. , 1990, Journal of neurosurgery.

[29]  J. Zentner,et al.  Noninvasive motor evoked potential monitoring during neurosurgical operations on the spinal cord. , 1989, Neurosurgery.

[30]  I. Whittle,et al.  Recording of spinal somatosensory evoked potentials for intraoperative spinal cord monitoring. , 1986, Journal of neurosurgery.

[31]  H. Ralston,et al.  The terminations of corticospinal tract axons in the macaque monkey , 1985, The Journal of comparative neurology.

[32]  H. Morton,et al.  Stimulation of the cerebral cortex in the intact human subject , 1980, Nature.

[33]  C. L. Nash,et al.  Spinal cord monitoring during operative treatment of the spine. , 1977, Clinical orthopaedics and related research.

[34]  W. M. Barclay.  Surgery , 1894, Bristol medico-chirurgical journal.

[35]  A. Friedman,et al.  Impact of Tumor Histology on Resectability and Neurological Outcome in Primary Intramedullary Spinal Cord Tumors: A Single-Center Experience With 102 Patients. , 2015, Neurosurgery.

[36]  A Bruno,et al.  Somatosensory- and motor-evoked potential monitoring during spine and spinal cord surgery , 2007, Spinal Cord.

[37]  T. Gasser,et al.  Functional outcome after surgical treatment of intramedullary spinal cord tumors: experience with 78 patients , 2005, Spinal Cord.

[38]  T Kirino,et al.  Bisegmental cervical interbody fusion using hydroxyapatite implants: surgical results and long-term observation in 70 cases. , 1998, Journal of neurosurgery.

[39]  L. Kearse,et al.  Loss of somatosensory evoked potentials during intramedullary spinal cord surgery predicts postoperative neurologic deficits in motor function [corrected]. , 1993, Journal of clinical anesthesia.

[40]  S. Kadoya.  Grading and scoring system for neurological function in degenerative cervical spine disease--Neurosurgical Cervical Spine Scale. , 1992, Neurologia medico-chirurgica.

[41]  John H. Martin.  Neuroanatomy: Text and Atlas , 1989 .

[42]  W. Levy.  Clinical experience with motor and cerebellar evoked potential monitoring. , 1987, Neurosurgery.

[43]  D. York.  Review of descending motor pathways involved with transcranial stimulation. , 1987, Neurosurgery.