Intraoperative NeuroMonitoring, some recent articles of interest!?.

Intraoperative subcortico-cortical evoked potentials of the visual pathway under general anesthesia

Cognitive Evoked Potential (P300)

Post-Concussion Syndrome after a Mine Blast Injury: Neuropsychological Consequences and Changes of the Cognitive Evoked Potentials (P 300)

 EMG & EEG

Nasopharyngeal electrodes in temporal lobe epilepsy: A reappraisal of their diagnostic utility

Evoked Potentials

Improving intraoperative evoked potentials at short latency by a novel neuro-stimulation technology with delayed return discharge

aEEG

Ambulatory EEG Monitoring, Reviewing, and Interpreting

TBI or Sports Brain Injuries-Diagnosis without Opening the Skull?

My Editorial and Review on Recent Trends in Brain Damage is next, in the mean time, this is the latest news about Traumatic Brain Injruy (TBI) and how Spreading Depolarization can be tapped using neuromonitoring and how that can be used to understand and interpret the brain damage without opening the skull, what I meant is without a neurosurgery?.

LLIF-Lateral Lumbar Interbody Fusion Procedure

This particular video taken during the Lateral Lumbar Interbody Fusion procedure at UPMC by Dr.Kanter and his team is a treat to watch the intricacy of surgical steps during lateral Spine procedure, you might have been into the OR or  probably done neuromonitoring for procedures including various lumbar level fusion procedures, but if there is no live camera equipped in the OR,  it is often difficult to know where exactly is the surgeon is and what is he/she is doing at a particular stage of the procedure, it will be just a guess work and that is not acceptable in the medical/health care field (all the stakeholders inside the OR must know exactly about the procedure) and that is not how things can go inside the Operating Room. Every team member from Anesthesiologist to Neurophysiologist to nurses must know every step of the way what exactly the surgeon is doing in order to help or figure out if there is any issue arise during surgical procedure. Unfortunately, most ORs are not equipped with the video transmission inside the OR or if there is one they normally do not use it (but in most neurosurgery ORs they do use). Those professionals who work inside the OR must acquaint themselves with surgical  steps of the surgeons, one way to do is watch it live or recorded one, or a demo before participating in such surgical procedure. It will provide a deeper understanding and realistic perception of how a particular procedure is done, with that knowledge handy, it will be more appropriate to provide feed back to the surgeon on neurophysiology or anesthesia or other relevant modalities to be monitored inside the OR. Even the X-Ray tech's must know the basics (most often that is not the case), ironically the cell saver and other tech's who come inside the OR have no clue about anything in the OR except that little machine collecting the blood?. Knowing exactly what the surgeon is doing every step of the way inside the OR provides a lot more close to a  realistic perception than reading it from a book or listening someone describe it. For those graduates or tech's who have not seen the details of this procedure, this is a good one to watch. Thanks to Dr.Kanter and his colleagues from UPMC for presenting this procedure so well.

Epilepsy: Drug Resistent Focal Epilepsy & Surgical Resection treatments, two Epilepsia Reports

Brain and Spine, 2014 Research Reports:

Fig from-Link: Human Epilepsy Patterns, focal epilepsy,

The following two new research reports published in Epilepsia journal [quoted Epilepsy current]might be of interest to those Epilepsy doctors and professionals, ofcourse to Neurophysiologists and long term intraoperative monitoring field.

Quoted: Current Literature In Clinical Science
Are HFOs Still UFOs? The Known and Unknown About High Frequency Oscillations in Epilepsy Surgery

High-Frequency Oscillations, Extent of Surgical Resection, and Surgical Outcome in Drug-Resistant Focal Epilepsy.

Haegelen C, Perucca P, Chatillon CE, Andrade-Valenca L, Zelmann R, Jacobs J, Collins DL, Dubeau F, Olivier A, Gotman J.

Epilepsia 2013;54:848–857.

PURPOSE: Removal of areas generating high-frequency oscillations (HFOs) recorded from the intracerebral electroencephalography
(iEEG) of patients with medically intractable epilepsy has been found to be correlated with improved surgical outcome. However, whether differences exist according to the type of epilepsy is largely unknown. We performed a comparative assessment of the impact of removing HFO-generating tissue on surgical outcome between temporal lobe epilepsy (TLE) and extratemporal lobe epilepsy (ETLE). We also assessed the relationship between the extent of surgical resectionand surgical outcome.

Read the full abstract at: http://www.aesnet.org/files/dmfile/epcu_13.6_273_ClinicalCommentary_Jobst.pdf#!
And the Full article at Epilesia journal.

Ripple Classification Helps to Localize the Seizure-Onset Zone in Neocortical Epilepsy.

Wang S, Wang IZ, Bulacio JC, Mosher JC, Gonzalez-Martinez J, Alexopoulos AV, Najm IM, So NK.

 Epilepsia 2013;54:370–376.

PURPOSE: Fast ripples are reported to be highly localizing to the epileptogenic or seizure-onset zone (SOZ) but may not be readily found in neocortical epilepsy, whereas ripples are insufficiently localizing. Herein we classified interictal neocortical ripples by associated characteristics to identify a subtype that may help to localize the SOZ in neocortical epilepsy. We hypothesize that ripples associated with an interictal epileptiform discharge (IED) are more pathologic,since the IED is not a normal physiologic event.

For full abstract and article, refer as the previous.

IONM: Neurological Testing or Neurophysiological Divining? J. G. Salamy, Ph.D.

Editorial Link:

Dr Joe Salamy writes a thought provoking and insightful Editorial Review about Intraoperative NeuroMonitoring, where do we stand?, what do we have to do to bring in new approach and newer technologies to avoid the IONM field become a stagnant one?..

IONM: Neurological Testing or Neurophysiological Divining? 

J. G. Salamy, Ph.D.  

VERTECz: surgical neurophysiology, Las Vegas, Nevada 

2012 All Rights Reserved

Email: 

Summary

During the last three decades IONM has followed an objective probability-based clinical model whichfocused attention almost exclusively upon the detection of specific events.  IONM practices, however, donot neatly conform to those of conventional clinical testing procedures.  It is suggested herein that futureefforts be directed toward developing additional models which elucidate the dynamic and subjectivequalities of IONM and recognize the importance of sequences and their influence upon decision making. Heretofore, the temporal and linguistic aspects of IONM have been largely ignored.  It is proposed that weexamine IOMN as an ongoing interactive process, and develop new tools to help accomplish this task.

For full Article , visit this Special Editorial column under the tabs: or click the following link

http://neuromonitoring1.blogspot.com/p/special-editorials.html

IONM news

Some updates:  http://drmunisneuromonitoring.blogspot.com/

Benefit of Intraoperative IONM and Expenses?...

The risks are minimal but they are real, and when you are not using the advanced technology and knowledge available to assess and safeguard the patients from risks of nerve damage or paralysis, your care is flawed and pretty dangerous, if you can spent 25 thousands for surgery and do not use Neuromonitoring that might cost another thousand or two, and you think that is cost effective, then something wrong with such ideas. Bringing safety inside OR must be the top priority of an operating surgeon (performing surgeon). There are several vascular or neurological complications happen during spine surgical procedures that may not be identified timely if you do not use neuromonitoring techniques, and when you find out after the surgery, it is too late.  

Electrocautery and Spinal Cord damage- loss of motor activities..!

Nerve damages or spinal cord damage during brain and spine surgical procedures depends upon various myraids of factors, one of them is mechanical. However, how many of you even thought of an electrocautery can produce spinal cord damage resulting EMGs and motor activity loss?. This report published in an porcine model discusses a case. I have not read a human case yet, but it is a real possibility, it can happen during surgery.  If anyone knows a human case or clinical scenario's, please post a comment below.

Spinal cord injury from electrocautery: observations in a porcine model using electromyography and motor evoked potentials. Stanley A. Skinner, et al  Journal of Clinical Monitoring and Computing November 2012

Abstract

We have previously investigated electromyographic (EMG) and transcranial motor evoked potential (MEP) abnormalities after mechanical spinal cord injury. We now report thermally generated porcine spinal cord injury, characterized by spinal cord generated hindlimb EMG injury activity and spinal cord motor conduction block (MEP loss). Electrocautery (EC) was delivered to thoracic level dural root sleeves within 6–8 mm of the spinal cord (n = 6). Temperature recordings were made near the spinal cord. EMG and MEP were recorded by multiple gluteobiceps intramuscular electrodes before, during, and after EC. Duration of EC was titrated to an end-point of spinal motor conduction block (MEP loss). In 5/6 roots, ipsilateral EMG injury activity was induced by EC. In 4/5 roots, EMG injury activity was identified before MEP loss. In all roots, a minimum of 20 s EC and a temperature maximum of at least 57 °C at the dural root sleeve were required to induce MEP loss. Unexpectedly, conduction block was preceded by an enhanced MEP in 4/6 trials. EMG injury activity, preceding MEP loss, can be seen during near spinal cord EC. Depolarization and facilitation of lumbar motor neurons by thermally excited descending spinal tracts likely explains both hindlimb EMG and an enhanced MEP signal (seen before conduction block) respectively. A thermal mechanism may play a role in some unexplained MEP losses during intraoperative monitoring. EMG recordings might help to detect abnormal discharges and forewarn the monitorist during both mechanical and thermal injury to the spinal cord.

Full PDF: click on the top right corner of the journal for pdf article. Link:

Vascular Complications During Thoracic Pedicle Screw Placement: What?. Is this even Possible, yes!.

Surgery insight: During surgical performance or surgical procedures and providing patient care, there is nothing like oh you mean that?, well that is very simple or take for granted in a casual way, one must show at most attention and care in every small to big steps, so do the neuromonitoring and anesthesia professionals, you can be of great help to surgeon when you detect changes or unusual activity that can get surgeons attention right away. Ofcourse for surgeons, there is no room for error but absolutely there is no room for Oh I have done 1000s of surgery, pricking a nerve or artery during my pedicle screw insertion is not going to happen, oh well, it did. The following paper describes a case and death of a patient two weeks after the surgery, so be diligent.

While reading this article :Thoracic pedicle screw placement: Free-hand technique  by Yongjung J. Kim, Lawrence G. Lenke regarding Scoliosis and thoraci pedicle screw placement, I came across the two back reference that startled me, an important and interesting reference about how vascular complications can occur by careless pedicle screw placement?..

Vascular complications 

22.Heini P, Scholl E, Wyler D, Eggli S. Fatal cardiac tamponade associated with posterior 
spinal instrumentation. A case report. Spine 1998;23:2226–30.  

Heini et al[22] described a case of fatal cardiac tamponade that
was due to a prick injury of the right coronary artery by a Kirschner
Neurology India | December 2005 | Vol 53 | Issue 4
CMYK517 517 Kim et al: Thoracic pedicle screw placement
wire. The injury was confirmed by autopsy after the patient died
12 days after surgery.

14. Suk SI, Kim WJ, Lee SM, Kim JH, Chung ER. Thoracic pedicle screw fixation in 
spinal deformities: are they really safe? Spine 2001;26:2049–57.   

Suk et al [14] described a case of an over­penetrated screw causing irritation of the thoracic aorta resulting in severe chest pain.

 25. Minor ME, Morrissey NJ, Peress R, Carroccio A, Ellozy S, Agarwal G, et al. 
Endovascular treatment of an iatrogenic thoracic aortic injury after spinal 
instrumentation: case report. J Vasc Surg 2004;39:893–6

 Recently Minor et al [25] reported endovascular  treatment of an iatrogenic aortic injury by misplaced thoracic pedicle screw at T5. 

I have not yet read all these three papers, I will comment further after I go through them all.

Current Trends in Pedicle Screw Stimulation techniques

PubMed Research Publications:

Latest review from Isley etal,  here is the most recent review article on Pedicle screw stimulation and evaluation using EMG monitoring techniques. It might be a good read to refresh the knowledge about the literature on pedicle screw tests.

Current trends in pedicle screw stimulation techniques: lumbosacral, thoracic, and cervical levels.

Abstract: Unequivocally, pedicle screw instrumentation has evolved as a primary construct for the treatment of both common and complex spinal disorders. However an inevitable and potentially major complication associated with this type of surgery is misplacement of a pedicle screw(s) which may result in neural and vascular complications, as well as impair the biomechanical stability of the spinal instrumentation resulting in loss of fixation. In light of these potential surgical complications, critical reviews of outcome data for treatment of chronic, low-back pain using pedicle screw instrumentation concluded that "pedicle screw fixation improves radiographically demonstrated fusion rates;" however the expense and complication rates for such constructs are considerable in light of the clinical benefit (Resnick et al. 2005a). Currently, neuromonitoring using free-run and evoked (triggered) electromyography (EMG) is widely used and advocated for safer and more accurate placement of pedicle screws during open instrumentation procedures, and more recently, guiding percutaneous placement (minimally invasive) where the pedicle cannot be easily inspected visually. The latter technique, evoked or triggered EMG when applied to pedicle screw instrumentation surgeries, has been referred to as the pedicle screw stimulation technique. As concluded in the Position Statement by the American Society of Neurophysiological Monitoring (ASNM), multimodality neuromonitoring using free-run EMG and the pedicle screw stimulation technique was considered a practice option and not yet a standard of care (Leppanen 2005). Subsequently, the American Association of Neurological Surgeons/Congress of Neurological Surgeons (AANS/CNS) Joint Section on Disorders of the Spine and Peripheral Nerves published their "Guidelines for the Performance of Fusion Procedures for Degenerative Disease of the Lumbar Spine" (Heary 2005, Resnick et al. 2005a, Resnick et al. 2005b). It was concluded that the "primary justification" of intraoperative neuromonitoring"... is the perception that the safety and efficacy of pedicle screw fixation are enhanced..." (Resnick et al. 2005b). However in summarizing a massive (over 1000 papers taken from the National Library of Medicine), contemporary, literature review spanning nearly a decade (1996 to 2003), this invited panel (Resnick et al. 2005b) recognized that the evidence-based documents contributing to the parts related to pedicle screw fixation and neuromonitoring were "... full of potential sources of error ..." and lacked appropriate, randomized, prospective studies for formulating rigid standards and guidelines. Nevertheless, current trends support the routine use and clinical utility of these neuromonitoring techniques. In particular free-run and triggered EMG have been well recognized in numerous publications for improving both the accuracy and safety of pedicle screw implantation. Currently, treatment with pedicle screw instrumentation routinely involves all levels of the spine - lumbosacral, thoracic, and cervical. Significant historical events, various neuromonitoring modalities, intraoperative alarm criteria, clinical efficacy, current trends, and caveats related to pedicle screw stimulation along the entire vertebral column will be reviewed.

PMID: Neurodiagn J. 2012 Jun;52(2):100-75.

22808751

[PubMed - in process]

Review of Neuromonitoring field 32 Years Ago?.

The utilization and importance of Neuromonitoring in hospital or intensive care set up was reviewed elaborately 32 years ago during 1985. Did anything change or how much change has took place in this field is quite interesting, while basic principles and intraoperative modalities discussed remain pretty much same today as 32 years ago, IONM field did make lots of progress ever since, better tests, analysis and interpretation of results got savvy and reliable upto 96-99% accuracy than it was during1985. Advancements in terms of application in various surgical procedure and combinatorial tests to yield better results, some newer techniques, and the entire hardware/machine technology certainly been upgraded to fit the Operating Room environment.

W.Hacks, the author of this review from the then FRG (West Germany, no longer the case after 90s unified Germany) made a remarkable attempt to provide insights 32 years ago. The review has been published in "Journal of Neurology (interestingly, the very first issue of this journal was published way back in the year 1891 that continued till today with the same name Journal of Neurology Volume 1 / 1891 - Volume 259 / 2012), quite an respectable journal in the field of neurology, it is still exist with the same name with a significant impact factor score of 3.85, ranked 33 among 185 clinical neurology journals [The top five Neurology journals are rated as follows:  (Neurology, Brain, Annals of Neurology, Journal of Neurotrauma, and Stroke, for an interesting review of these top journals, click here LINK).

Here is the link to the partial or one page review available at the bottom of this abstract, it is a pay per view article, only one page is viewable for non subscribers.

Abstract

Neuromonitoring—the continuous or intermittent observation of nervous system functions—has become a field of interdisciplinary interest. Basically there are two major applications of neuromonitoring: in the operating theatre and the neurological or neurosurgical intensive care unit. Evoked potential recording, intracranial pressure measurement, serial EEG recording, cerebral blood flow measurement and ultrasound techniques have all been used as monitoring methods. The application of these techniques for operations, intensive care and the evaluation of brain death will be described.

Key words  Neuromonitoring - Intraoperative monitoring - Evoked potential monitoring - Spinal cord monitoring - Brain death

http://resources.metapress.com/pdf-preview.axd?code=kpj1622557hv431x&size=largest

American Academy of Neurology-Policy on Intraoperative Neuromonitoring!

The American Academy of Neurology has put up this policy on Intraoperative Neuromonitoring, though old but it is interesting note some observations like the following multicenter evaluation study on SSEPs, it is an impressive result as far as SSEPs concerned.

2. Multicenter Data in Spinal Surgeries

An extensive multicenter study conducted in 1995 demonstrated that IOM using SEP reduced the
risk of paraplegia by 60% in spinal surgeries (Nuwer et al., 1995). The incidence of false
negative cases, wherein an operative complication occurred without having been detected by the
monitoring procedure, was small: 0.06% (Nuwer et al., 1995).

ABNM- Latest Schedules of Exams

American Board of Neurophysiologic Monitoring

Exam Application Requirements for Application Written Exam Oral Exam Recertification Policy and Procedures Official List of Diplomates Officers and Board

Next Written Exams Certification Examination in Neurophysiologic Monitoring - Part I - Written Application Deadline Examination Date 12/31/2009 2/6/2010 - 2/20/2010 6/28/2010 8/7/2010-8/21/2010 Next Oral Exams Certification Examination in Neurophysiologic Monitoring - Part II - Oral Application Deadline Examination Date Location 4/5/2010 4/25/2010 Nashville, TN only 10/4/2010 10/24/2010 Chicago, IL only For information about registering for these tests please contact the Professional Testing Corporationor email us at info@abnm.info. Check the site: http://www.ptcny.com/clients/ABNM/index.html

Dexmedetomidine- A New Short Term Sedative?

Interesting Review on "Dexmedetomidine", the most recent sedative approved by the FDA.

Dexmedetomidine: a novel sedative-analgesic agent Ralph Gertler, MD,1 H. Cleighton Brown, MD,1 Donald H. Mitchell, MD,1 and Erin N. Silvius, MD1 1From the Department of Anesthesiology and Pain Management, Baylor University Medical Center, Dallas, Texas; and Department of Anesthesiology and Pain Management, The University of Texas Southwestern Medical Center at Dallas. Corresponding author. Corresponding author: Ralph Gertler, MD, Department of Anesthesiology and Pain Management, Baylor University Medical Center, 3500 Gaston Avenue, Dallas, Texas 75246 (e-mail: Ralph_Gertler10@excite.com). Since the first report of clonidine, an α2-adrenoceptor agonist, the indications for this class of drugs have continued to expand. In December 1999, dexmedetomidine was approved as the most recent agent in this group and was introduced into clinical practice as a short-term sedative (<24 style="font-size: 0.8em; line-height: 0.8em; white-space: nowrap; ">2-Adrenoceptor agonists have several beneficial actions during the perioperative period. They decrease sympathetic tone, with attenuation of the neuroendocrine and hemodynamic responses to anesthesia and surgery; reduce anesthetic and opioid requirements; and cause sedation and analgesia. They allow psychomotoric function to be preserved while letting the patient rest comfortably. With this combination of effects, α2-adrenoceptor agonists may offer benefits in the prophylaxis and adjuvant treatment of perioperative myocardial ischemia. Furthermore, their role in pain management and regional anesthesia is expanding. Side effects consist of mild to moderate cardiovascular depression, with slight decreases in blood pressure and heart rate. The development of new, more selective α2-adrenoceptor agonists with improved side effect profiles may provide a new concept for the administration of perioperative anesthesia and analgesia. This review aims to give background information to improve understanding of the properties and applications of the novel α2-adrenoceptor agonist, dexmedetomidine.

NeuroMonitoring in Epilepsy Related Diseases & Surgeries!?.

Journal of Neurosurgical Focus
In the latest issue of the journal JNS, Scellig S. D. Stone, M.D., and James T. Rutka from The Hospital for Sick Children, and The University of Toronto, Ontario, Canada discuss issues relate to the topic "challenges in Epilepsy related diseases and neurosurgeries in epilepsy patients". 

These challenges can provide great opportunities for neuromonitoring, infact, in this very review you will find that the existing brain mapping and EcoG has been a gold standard to conduct successeful neurosurgeries, it has become an important tool for surgeons to identify and map the areas in epilepsy patients who undergo surgeries to get rid of the epileptic loci in the brain.

The authors described two combined approach that can be used to delineate a possible trajectory for the epilepsy surgeons, such methods may help to relieve the patients from epileptic activities. 

The neuronavigation system and the neuromonitoring approach, I will try to condense the information regarding neuromonitoring here, but one must read the whole article to get a better insight into this field. Three of the exisiting neuromonitoring protocols are discussed,

1.Electrocorticography recording method, using this method one can reliably map the brain areas of interest for surgical removal by directly placing grid electrodes on the surface of brain (invasive), using the method poineered by the Penfield and Jasper [34.Jasper H, Electrocorticography. Penfield W, Jasper H: Epilepsy and the Functional Anatomy of the Human Brain Boston, Little Brown, 1954. 692–738].

2.Depth Electrode Recordings, this method can be combined with the direct mapping of the brain using depth electrode, deep isertion of electrodes into subcortical areas will provide additional information about ictical and interactive epileptic regions, in reality, the DER can be performed outside the OR perioperatively as well as inside the OR intraoperatively, enabling the surgeon to develop a streamlined strategy into the brain area of interest to be lesioned, lesioning brain areas is the surgical procedures carried out to eliminate epileptic activities.

3.Intraoperative EcoG is  yet another recording used widely to operate on interactive epileptic patients, the most important use of EcoG seems to be to during extralesional resections or lesionectomy combined with spike-positive tissue resection procedures. EcoG monitoring seems to have helped reduce the rate of second surgical procedure and reduced epileptic activities significantly in those patients. One of the surgical procedure where EcoG was very useful in the removal of the hippocampal area or mesial temporal or gliosis surgical procedures.

4.Direct Cortical Stimulation method, mostly used in surgeries that involve sensory motor or language areas, a direct application of focal cortical pulses of low voltage current using a hand held bipolar electrode.

So, applying these

techniques in combination as a "multi-model" neuromonitoring procedure

can go long way in safegurding better surgical procedures in epilepsy patients. This is a great review any neurophysiologist or neurosurgeon or neurologist or neuromonitoring personnel must read for better understanding of surgical procedures and neuromonitoring in epilepsy patients.

Neuromonitoring Signal Changes during Spinal Epidural Hematoma?

Are there non-surgical factors that can cause spinal cord damage???......,

oh yes, 

there are few non-surgically induced damages that might go unnoticed in the absence of intraoperative neuromonitoring such as ischaemia, hematoma, stroke and so on...?.

 The following work demonstrates the timely detection of epidural hematoma by neurophysiological wave form changes.

the disappearance of evoked potentials and the subsequent appearance of paraplegia in our patient was unlikely to be caused by the epidural LA, but probably by the occurrence of the spinal epidural hematoma as a complication of epidural catheterization.

Acute spinal cord dysfunction was revealed by INM, then elucidated by imaging of the spine. The whole sequence of events led to timely urgent neurosurgical intervention which resulted in complete restoration of motor and sensory functions.

Our patient’s case supports the value of evoked-potential monitoring during spinal surgery.

This case and previous work offer arguments that evoked potentials are relatively insensitive to epidural LAs, but nevertheless we suggest that neuraxial LAs better be avoided in cases in which INM is used.

IONM the Gold Standard of Patient Safety? By David J.Anschel, M.D

David J. Anschel, M.D.
Contributing Editor of MedCompare,

David J. Anschel writes about the developments in "Itraoperative Neurophysiological Monitoring and its medical usage:

IONM has become the gold standard for ensuring patient safety while undergoing operations which place the central or peripheral nervous system at risk. Technological advancements within the last few years have allowed monitoring techniques to evolve. The above robust systems are representative of the best that modern medicine has to offer. Allowing neurologists and surgeons to work together to provide better patient outcomes during more complicated procedures in close proximity to vital neurological tissues.

Benign Or Metastatic Tumor Removal &The importance of IntraOperative Neuromonitoring

Resection of a benign brachial plexus nerve sheath tumor using intraoperative electrophysiological monitoring.

Kwok K, Davis B, Kliot M.
Department of Neurosurgery,
University of California at Davis, Sacramento, California 95825, USA. keithkwok2004@yahoo.com

OBJECTIVE: Benign peripheral nerve sheath tumors arising from the brachial plexus are rare. Neurosurgeons often lack the clinical and surgical experience to optimize the management of these uncommon tumors. We filmed a video depicting the surgical resection of a benign peripheral nerve sheath tumor involving the brachial plexus. METHODS: An illustrative case was used to demonstrate the proper management of a brachial plexus nerve sheath tumor including the important role of intraoperative electrophysiological neuromonitoring during tumor resection. RESULTS: Using an illustrative case, we describe a systematic approach in the evaluation and surgical management of patients with a brachial plexus nerve sheath tumor. The importance of taking a thorough clinical history, performing a thorough physical examination, applying high-resolution magnetic resonance imaging techniques to visualize the pathology, and using intraoperative electrophysiological neuromonitoring during surgical exposure and resection of the tumor are stressed. Combined with appropriate postoperative treatment, these techniques minimize the risks and increase the likelihood of achieving a good clinical outcome. CONCLUSION: Brachial plexus nerve sheath tumors are challenging mass lesions that should be evaluated and surgically resected by an experienced team of physicians to optimize clinical outcome.

Neuromonitoring during surgery for metastatic tumors to the spine: intraoperative interpretation and management strategies.
Quiñones-Hinojosa A, Lyon R, Ames CP, Parsa AT.

Department of Neurological Surgery,
Brain Tumor Research Center, University of California-San Francisco,
505 Parnassus Avenue, M-779, San Francisco, CA 94143-0112, USA.
quinones@neurosurg.ucsf.edu

Resection of metastatic tumors of the spine poses great technical challenges, with the potential of creating severe neurologic deficits. Several modalities of electrophysiologic monitoring, including SSEPs and MEPs, have evolved to aid in resection of these tumors. This review has presented additional techniques-such as mapping of the dorsal columns with antidromic-elicited SSEPs to plan the myelotomy and direct intra-medullary stimulation-that help to identify the extent of the tumor margin at its interface with functional tracts. Neuromonitoring can potentially minimize the sensory and motor damage that can occur during resection of metastatic tumors of the spine. Further experience with these techniques should allow improved results follow-ing surgical procedures in functionally eloquent are as of the spinal cord during the surgical management of metastatic tumors