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Analgesic efficacy of surgeon placed paravertebral catheters compared with thoracic epidural analgesia after Ivor Lewis esophagectomy: a retrospective non-inferiority study. J Thorac Dis 2024; 16:414-422. [PMID: 38410611 PMCID: PMC10894387 DOI: 10.21037/jtd-23-689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 12/01/2023] [Indexed: 02/28/2024]
Abstract
Background The Ivor Lewis esophagectomy is an operation that involves a laparotomy and a right thoracotomy, both of which are associated with severe postoperative pain and subsequent impairment of respiratory function. Currently, the accepted "gold standard" for postoperative analgesia for laparotomies and thoracotomies is the thoracic epidural. A systematic review has shown paravertebral blocks to be equivalent to epidural analgesia for post-thoracotomy pain control and have decreased incidence of nausea and vomiting, hypotension and respiratory depression. To our knowledge, the use of the paravertebral catheter (PVC) in open Ivor Lewis esophagectomy has not been formally studied. The primary outcome is the area under the curve (AUC) pain scores in the first 48 hours after surgery. Methods We performed a retrospective chart review of the open Ivor Lewis esophagectomy patients at our local institution, with local research ethics board (REB) approval. Results A total of 92 patients were included in this study: 43 patients had a PVC and 49 had a thoracic epidural for postoperative pan control. Overall, the PVC group was non-inferior and statistically equivalent to the epidural group. Time to ambulation in the PVC group was non-inferior compared to epidurals. The PVC group was superior when comparing total opioid consumption. Conclusions Our retrospective study continues to challenge the role of epidurals as the gold standard of pain control post thoracotomy and laparotomy. Further prospective studies with a larger population are needed to better compare the two modalities.
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Analyzing the value of IONM as a complex intervention: The gap between published evidence and clinical practice. Clin Neurophysiol 2023; 151:59-73. [PMID: 37163826 DOI: 10.1016/j.clinph.2023.03.364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 02/25/2023] [Accepted: 03/20/2023] [Indexed: 05/12/2023]
Abstract
OBJECTIVE Intraoperative neurophysiological monitoring (IONM) was investigated as a complex intervention (CI) as defined by the United Kingdom Medical Research Council (MRC) in published studies to identify challenges and solutions in estimating IONM's effects on postoperative outcomes. METHODS A scoping review to April 2022 of the influence of setting on what was implemented as IONM and how it influenced postoperative outcomes was performed for studies that compared IONM to no IONM cohorts. IONM complexity was assessed with the iCAT_SR tool. Causal graphs were used to represent this complexity. RESULTS IONM implementation depended on the surgical procedure, institution and/or surgeon. "How" IONM influenced neurologic outcomes was attributed to surgeon or institutional experience with the surgical procedure, surgeon or institutional experience with IONM, co-interventions in addition to IONM, models of IONM service delivery and individual characteristics of the IONM provider. Indirect effects of IONM mediated by extent of tumor resection, surgical approach, changes in operative procedure, shorter operative time, and duration of aneurysm clipping were also described. There were no quantitative estimates of the relative contribution of these indirect effects to total IONM effects on outcomes. CONCLUSIONS IONM is a complex intervention whose evaluation is more challenging than that of a simple intervention. Its implementation and largely indirect effects depend on specific settings that are usefully represented in causal graphs. SIGNIFICANCE IONM evaluation as a complex intervention aided by causal graphs and multivariable analysis could provide a valuable framework for future study design and assessments of IONM effectiveness in different settings.
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Intraoperative glucose management: when to monitor and who to treat? Can J Anaesth 2023; 70:177-182. [PMID: 36450942 DOI: 10.1007/s12630-022-02358-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 10/06/2022] [Accepted: 10/11/2022] [Indexed: 12/05/2022] Open
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Postoperative mortality risk prediction that incorporates intraoperative vital signs: development and internal validation in a historical cohort. Can J Anaesth 2022; 69:1086-1098. [PMID: 35996071 DOI: 10.1007/s12630-022-02287-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 03/08/2022] [Accepted: 03/09/2022] [Indexed: 12/23/2022] Open
Abstract
PURPOSE Accurate risk reassessment after surgery is crucial for postoperative planning for monitoring and disposition. Existing postoperative mortality risk prediction models using preoperative features do not incorporate intraoperative hemodynamic derangements that may alter risk stratification. Intraoperative vital signs may provide an objective and readily available prognostic resource. Our primary objective was to derive and internally validate a logistic regression (LR) model by adding intraoperative features to established preoperative predictors to predict 30-day postoperative mortality. METHODS Following Research Ethics Board approval, we analyzed a historical cohort that included patients aged ≥ 45 undergoing noncardiac surgery with an overnight stay at two tertiary hospitals (2013 to 2017). Features included intraoperative vital signs (blood pressure, heart rate, end-tidal carbon dioxide partial pressure, oxygen saturation, and temperature) by threshold and duration of exposure, as well as patient, surgical, and anesthetic factors. The cohort was divided temporally 75:25 into derivation and validation sets. We constructed a multivariable LR model with 30-day all-cause mortality as the outcome and evaluated performance metrics. RESULTS There were 30,619 patients in the cohort (mean [standard deviation] age, 66 [11] yr; 50.2% female; 2.0% mortality). In the validation set, the primary LR model showed a c-statistic of 0.893 (99% confidence interval [CI], 0.853 to 0.927), a Nagelkerke R-squared of 0.269, a scaled Brier score of 0.082, and an area under precision-recall curve of 0.158 (baseline 0.017 for an uninformative model). The addition of intraoperative vital signs to preoperative factors minimally improved discrimination and calibration. CONCLUSION We derived and internally validated a model that incorporated vital signs to improve risk stratification after surgery. Preoperative factors were strongly predictive of mortality risk, and intraoperative predictors only minimally improved discrimination. External and prospective validations are needed. STUDY REGISTRATION www. CLINICALTRIALS gov (NCT04014010); registered on 10 July 2019.
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Neurophysiology during epilepsy surgery. HANDBOOK OF CLINICAL NEUROLOGY 2022; 186:103-121. [PMID: 35772880 DOI: 10.1016/b978-0-12-819826-1.00017-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Intraoperative neuromonitoring (IONM) complements modern presurgical investigations by providing information about the epileptic focus as well as real-time identification of critical functional tissue and assessment of ongoing neural integrity during resective epilepsy surgery. This chapter summarizes current IONM methods for mapping the epileptic focus and for mapping and monitoring functionally important structures with direct brain stimulation and evoked potentials. These techniques include electrocorticography, computerized high-frequency oscillation mapping, single-pulse electric stimulation, cortical and subcortical motor evoked potentials, somatosensory evoked potentials, visual evoked potentials, and cortico-cortical evoked potentials. They may help to maximize epileptic tissue resection while avoiding permanent postoperative neurologic deficits.
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Monitoring scoliosis and other spinal deformity surgeries. HANDBOOK OF CLINICAL NEUROLOGY 2022; 186:179-204. [PMID: 35772886 DOI: 10.1016/b978-0-12-819826-1.00014-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Surgery to correct a spinal deformity incurs a risk of injury to the spinal cord and roots. Injuries include postoperative paraplegia. Surgery for cervical myelopathy also incurs risk for postoperative motor deficits, as well as nerve injury most commonly at the C5 root. Risks can be mitigated by monitoring the nervous system during surgery. Ideally, monitoring detects an impending injury in time to intervene and correct the impairment before it becomes permanent. Monitoring includes several modalities of testing. Somatosensory evoked potentials measure axonal conduction in the spinal cord posterior columns. This can be checked almost continuously during surgery. Motor evoked potentials measure conduction along the lateral corticospinal tracts. Because motor pathway stimulation often produces a patient movement on the table, these often are tested periodically rather than continuously. Electromyography observes for spontaneous discharges accompanying injuries, and is useful to assess misplacement of pedicle screws. Literature demonstrates the usefulness of these techniques, their association with reducing motor adverse outcomes, and the relative value of the techniques. Neurophysiologic monitoring for scoliosis, kyphosis, and cervical myelopathy surgery are addressed, along with background information about those conditions.
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Abstract
There are many recent advances in intraoperative evoked potential techniques for mapping and monitoring neural function during surgery. In particular, somatosensory evoked potential optimization speeds surgical feedback, motor evoked potentials provide selective motor system information, and new visual evoked potential methods promise reliable visual system monitoring. This chapter reviews these advances and provides a comprehensive background for understanding their context and importance.
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Preface. HANDBOOK OF CLINICAL NEUROLOGY 2022; 186:xi. [PMID: 35772903 DOI: 10.1016/b978-0-12-819826-1.09997-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
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Perioperative Acute Care of Older Patients Living with Frailty. CURRENT ANESTHESIOLOGY REPORTS 2019. [DOI: 10.1007/s40140-019-00355-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Personalized perioperative medicine: a scoping review of personalized assessment and communication of risk before surgery. Can J Anaesth 2019; 66:1026-1037. [DOI: 10.1007/s12630-019-01432-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 03/10/2019] [Accepted: 03/11/2019] [Indexed: 01/14/2023] Open
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Correction to: Is the new ASNM intraoperative neuromonitoring supervision "guideline" a trustworthy guideline? A commentary. J Clin Monit Comput 2019; 33:191-192. [PMID: 30778916 PMCID: PMC6420422 DOI: 10.1007/s10877-019-00266-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Is the new ASNM intraoperative neuromonitoring supervision "guideline" a trustworthy guideline? A commentary. J Clin Monit Comput 2019; 33:185-190. [PMID: 30612285 PMCID: PMC6420437 DOI: 10.1007/s10877-018-00242-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 12/22/2018] [Indexed: 11/29/2022]
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Letter: Guidelines for the use of Electrophysiological Monitoring for Surgery of the Human Spinal Column and Spinal Cord. Neurosurgery 2018; 83:E82-E84. [DOI: 10.1093/neuros/nyy231] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Standardized computer-based organized reporting of EEG: SCORE – Second version. Clin Neurophysiol 2017; 128:2334-2346. [DOI: 10.1016/j.clinph.2017.07.418] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 07/25/2017] [Accepted: 07/27/2017] [Indexed: 10/19/2022]
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Intraoperative direct cortical stimulation motor evoked potentials: Stimulus parameter recommendations based on rheobase and chronaxie. Clin Neurophysiol 2017; 128:2300-2308. [PMID: 29035822 DOI: 10.1016/j.clinph.2017.09.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 08/04/2017] [Accepted: 09/19/2017] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To determine optimal interstimulus interval (ISI) and pulse duration (D) for direct cortical stimulation (DCS) motor evoked potentials (MEPs) based on rheobase and chronaxie derived with two techniques. METHODS In 20 patients under propofol/remifentanil anesthesia, 5-pulse DCS thenar MEP rheobase and chronaxie with 2, 3, 4 and 5ms ISI were measured by linear regression of five charge thresholds at 0.05, 0.1, 0.2, 0.5 and 1msD, and estimated from two charge thresholds at 0.1 and 1msD using simple arithmetic. Optimal parameters were defined by minimum threshold energy: the ISI with lowest rheobase2×chronaxie, and D at its chronaxie. Near-optimal was defined as threshold energy <25% above minimum. RESULTS The optimal ISI was 3 or 4 (n=7 each), 2 (n=4), or 5ms (n=2), but only 4ms was always either optimal or near-optimal. The optimal D was ∼0.2 (n=12), ∼0.1 (n=7) or ∼0.3ms (n=1). Two-point estimates closely approximated five-point measurements. CONCLUSIONS Optimal ISI/D varies, with 4ms/0.2ms being most consistently optimal or near-optimal. Two-point estimation is sufficiently accurate. SIGNIFICANCE The results endorse 4ms ISI and 0.2msD for general use. Two-point estimation could enable quick individual optimization.
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ACNS Guideline: Transcranial Electrical Stimulation Motor Evoked Potential Monitoring. J Clin Neurophysiol 2016; 33:42-50. [PMID: 26756258 DOI: 10.1097/wnp.0000000000000253] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
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Motor and somatosensory evoked potential spinal cord monitoring during intubation and neck extension for thyroidectomy in a Down syndrome boy with atlantoaxial instability. J Clin Monit Comput 2016; 31:231-233. [PMID: 26820847 DOI: 10.1007/s10877-016-9832-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 01/20/2016] [Indexed: 10/22/2022]
Abstract
Intubation or neck extension can compress the spinal cord in patients with craniocervical instability. Protective motor evoked potential (MEP) and somatosensory evoked potential (SEP) monitoring of these maneuvers is an obvious consideration when these patients undergo already-monitored spinal surgery, but might be overlooked when they undergo other normally unmonitored procedures. Here we report monitoring intubation and neck extension for the unusual indication of thyroidectomy in a Down syndrome boy with atlantoaxial instability. Transcranial electric stimulation thenar MEPs and optimized median nerve SEPs were acquired about every minute throughout intubation and neck extension under propofol and remifentanil anesthesia without neuromuscular blockade. Potentials were stable and there was no neurologic deficit. This approach could protect craniocervical instability patients against cord compression when they undergo intubation and neck extension for surgical procedures that would not otherwise indicate spinal cord monitoring.
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Intraoperative neuromonitoring for the prevention of iatrogenic injury during cervical and thoracic spine surgery. Hippokratia 2015. [DOI: 10.1002/14651858.cd011835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Abstract
OBJECTIVE To review the neurologic, neuroradiologic, and electrophysiologic features of autosomal recessive horizontal gaze palsy and progressive scoliosis (HGPPS), a syndrome caused by mutation of the ROBO3 gene on chromosome 11 and associated with defective decussation of certain brainstem neuronal systems. METHODS The authors examined 11 individuals with HGPPS from five genotyped families with HGPPS. Eight individuals had brain MRI, and six had electrophysiologic studies. RESULTS Horizontal gaze palsy was fully penetrant, present at birth, and total or almost total in all affected individuals. Convergence, ocular alignment, congenital nystagmus, and vertical smooth pursuit defects were variable between individuals. All patients developed progressive scoliosis during early childhood. All appropriately studied patients had hypoplasia of the pons and cerebellar peduncles with both anterior and posterior midline clefts of the pons and medulla and electrophysiologic evidence of ipsilateral corticospinal and dorsal column-medial lemniscus tract innervation. Heterozygotes were unaffected. CONCLUSIONS The major clinical characteristics of horizontal gaze palsy and progressive scoliosis were congenital horizontal gaze palsy and progressive scoliosis with some variability in both ocular motility and degree of scoliosis. The syndrome also includes a distinctive brainstem malformation and defective crossing of some brainstem neuronal pathways.
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Tibial somatosensory evoked potential intraoperative monitoring: recommendations based on signal to noise ratio analysis of popliteal fossa, optimized P37, standard P37, and P31 potentials. Clin Neurophysiol 2005; 116:1858-69. [PMID: 16005261 DOI: 10.1016/j.clinph.2005.04.018] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2005] [Revised: 04/08/2005] [Accepted: 04/27/2005] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To compare the intraoperative signal-to-noise ratio (SNR), reproducibility and rapidity of popliteal fossa (PF), optimized P37, standard P37 and P31 potentials. METHODS Raw sweeps and 11 averages doubling sweep number from 2 to 2048 were compared in 37 patients undergoing scoliosis surgery. Optimized (highest amplitude or SNR) P37 derivations were Cz-CPc (22), CPz-CPc (27), Pz-CPc (7), iCPi-CPc (8), CPi-CPc (1), Cz-Pz (2) or Pz-FPz (3), and in two patients with non-decussation, Cz-CPi (1) or CPz-CPi (3). Standard P37 and P31 derivations were CPz-FPz and FPz-C5S. Signal amplitude was measured in 2048-sweep averages; peak noise was measured in raw sweeps and +/- averages; SNR was amplitude/noise. Visual superimposability and < 20-30% amplitude variation determined reproducibility. Sweeps to reproducibility determined rapidity. RESULTS The SNR order was PF >> optimized P37 > standard P37 > P31. Mean optimized P37 SNR advantages over the standard P37 and P31 were 2.1:1 and 4.9:1. SNR had powerful non-linear correlations to reproducibility and rapidity. Median sweeps to reproducibility were PF: 2, optimized P37: 128, standard P37: 512 and P31: 1024. EEG noise was greatest in FPz derivations. Burst-suppression increased scalp potential SNR and rapidity. CONCLUSIONS Optimized P37 and PF recordings are most rapidly reproducible due to superior SNRs and are recommended. FPz should be avoided. Burst-suppression may be desirable. SIGNIFICANCE CPz-FPz and FPz-C5S should no longer be standard.
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Re: Comparison of monitoring techniques for intraoperative cerebral ischemia. DW Rowed, DA Houlden, LM Burkholder, AB Taylor. Can J Neurol Sci 2004;31(3):347-356. Can J Neurol Sci 2005; 32:131-2; author reply 132. [PMID: 15825563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
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A comparison between derivation optimization and Cz′–FPz for posterior tibial P37 somatosensory evoked potential intraoperative monitoring. Clin Neurophysiol 2004; 115:1925-30. [PMID: 15261872 DOI: 10.1016/j.clinph.2004.03.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/05/2004] [Indexed: 11/23/2022]
Abstract
OBJECTIVE To compare P37 derivation optimization to Cz'-FPz. METHODS After induction in 120 patients, monitoring derivations optimized by mapping FPz, Cz, Cz', Pz, C4', C2', C1' and C3'-mastoid to determine the P37 and N37 maximums for use as inputs 1 and 2 were compared to Cz'-FPz. This was repeated later in 35 surgeries. RESULTS Eleven optimal derivations occurred and usually differed between sides. Input 1 was Cz', Pz, Cz, iCi', or Ci' and input 2 was Cc', FPz, Ci' or Pz. Even the most frequent Cz'-Cc' derivation was optimal for both sides of an individual in only 17% and this was true for Cz'-FPz in only 4%. Optimization produced higher amplitudes than Cz'-FPz (P<0.001). The ratio was [squareroot of 2] : 1 in 61% of patients and > or =2:1 in 28%, approximately halving or quartering averaging times. Optimization assessed decussation, disclosing non-decussation in one patient while Cz'-FPz did not. Alterations of P37 topography that reduced initially optimal derivation amplitude and made a different derivation optimal were demonstrated by repeat optimization in 13 of 35 patients, preventing misinterpretation in one. While also affected, Cz'-FPz neither detected nor adjusted for potentially misleading topographic changes. CONCLUSIONS Higher amplitudes, decussation assessment and topographic adjustment make P37 derivation optimization superior to Cz'-FPz for monitoring this highly variable potential.
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Abstract
The mechanisms controlling axon guidance are of fundamental importance in understanding brain development. Growing corticospinal and somatosensory axons cross the midline in the medulla to reach their targets and thus form the basis of contralateral motor control and sensory input. The motor and sensory projections appeared uncrossed in patients with horizontal gaze palsy with progressive scoliosis (HGPPS). In patients affected with HGPPS, we identified mutations in the ROBO3 gene, which shares homology with roundabout genes important in axon guidance in developing Drosophila, zebrafish, and mouse. Like its murine homolog Rig1/Robo3, but unlike other Robo proteins, ROBO3 is required for hindbrain axon midline crossing.
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Intraoperative neurophysiologic discovery of uncrossed sensory and motor pathways in a patient with horizontal gaze palsy and scoliosis. Clin Neurophysiol 2004; 115:576-82. [PMID: 15036053 DOI: 10.1016/j.clinph.2003.10.029] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/16/2003] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To report the intraoperative neurophysiologic discovery of clinically unsuspected non-decussation of the somatosensory and motor pathways. METHODS We performed somatosensory evoked potential (SEP) and transcranial electric stimulation (TES) muscle motor evoked potential (MEP) monitoring during scoliosis surgery for a 16 year old patient with familial horizontal gaze palsy and progressive scoliosis. Our routine procedures included optimizing tibial cortical SEP monitoring derivations through saggital and coronal (C4', C2', Cz', C1', C3'-mastoid) P37 mapping, which surprisingly indicated non-decussation. Consequently, we also obtained coronal median nerve SEPs and simultaneous bilateral muscle recordings to lateralized TES (C3-Cz, C4-Cz) intraoperatively and focal hand area transcranial magnetic stimulation (TMS) postoperatively. RESULTS For each nerve, tibial P37/N37 distribution was contralateral/ipsilateral and median N20 ipsilateral. For each hemisphere, ipsilateral TES MEPs had lower thresholds and TMS MEPs were exclusively ipsilateral. Accurate monitoring required reversed montages. Reevaluation of an MRI (previously reported normal) disclosed a ventral midline cleft of the medulla. CONCLUSIONS The results indicate uncrossed dorsal column-medial lemniscal and corticospinal pathways due to brain-stem malformation with absent internal arcuate and pyramidal decussations. SIGNIFICANCE Simultaneous bilateral recording to unilateral stimulation demonstrates SEP/MEP hemispheric origin and is important for accurate interpretation and monitoring because decussation anomalies exist.
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Monitoring scoliosis surgery with combined multiple pulse transcranial electric motor and cortical somatosensory-evoked potentials from the lower and upper extremities. Spine (Phila Pa 1976) 2003; 28:194-203. [PMID: 12544939 DOI: 10.1097/00007632-200301150-00018] [Citation(s) in RCA: 170] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN A retrospective case review was performed. OBJECTIVE To assess the value, rapidity, and safety of combined multiple-pulse transcranial electric stimulation motor-evoked potential and somatosensory-evoked potential monitoring during scoliosis surgery. SUMMARY OF BACKGROUND DATA Leg somatosensory-evoked potentials can miss motor deficits, and a 50% amplitude warning criterion can produce false alarms. METHODS For this study, 33 scoliosis surgeries in neurologically normal patients under propofol/fentanyl anesthesia omitting neuromuscular blockade were monitored with four-extremity multiple-pulse transcranial electric stimulation muscle motor-evoked potentials and cortical somatosensory-evoked potentials. Instead of amplitude criteria, parallel (same-direction) change was used to identify systemic alteration and nonparallel (one- or two-limb) deterioration to identify focal neurologic compromise. Clinical observation and intraoperative electroencephalography were used to assess adverse effects. RESULTS Instantaneous motor-evoked potentials and rapidly reproducible cortical somatosensory-evoked potentials provided comprehensive feedback every 0.8 to 6.7 minutes (median, 2.4 minutes) without adverse effects. Parallel (systemic) changes without alarm or deficit included motor-evoked potential fading or temporary loss and leg somatosensory-evoked potential amplitudes below 50% of initial, maximum, or median intraoperative values in 10% to 37% of the cases. Three nonparallel changes occurred: 1) abrupt bilateral leg somatosensory-evoked potential 20% to 30% reduction without motor-evoked potential change during instrumentation resolving spontaneously over 30 minutes, with transient postoperative sensory symptoms; 2) right-arm somatosensory-evoked potential and motor-evoked potential reduction during hyperabduction restored after repositioning, without deficit; 3) abrupt bilateral leg motor-evoked potential loss preceding 30% to 60% somatosensory-evoked potential reduction during derotation rapidly restored after instrumentation release, without deficit. CONCLUSIONS In neurologically normal patients, the combined methods are safe and rapid, and could improve the sensitivity and specificity of scoliosis monitoring. Arm controls facilitate differentiation between systemic alterations and focal neurologic compromise.
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Intraoperative spinal cord monitoring during descending thoracic and thoracoabdominal aneurysm surgery. Ann Thorac Surg 2002; 74:S1873-6; discussion S1892-8. [PMID: 12440684 DOI: 10.1016/s0003-4975(02)04137-1] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
BACKGROUND Postoperative paraplegia is one of the most dreaded complications after descending thoracic and thoracoabdominal aneurysm surgery. In this study, intraoperative monitoring was applied during resection of descending thoracic and thoracoabdominal aneurysms to detect spinal cord ischemia and help prevent paraplegia. METHODS Fifty-six patients (descending thoracic, 25; thoracoabdominal, 31) were monitored intraoperatively with both motor- (MEP) and somatosensory- (SSEP) evoked potentials. MEPs were elicited with transcranial electrical stimulation and recorded from the spinal epidural space (D wave) or peripheral muscles (myogenic MEP). SSEPs were obtained with median and tibial nerve stimulation. RESULTS A total of 16 patients (28.6%) showed MEP evidence of spinal cord ischemia, only 4 of whom had delayed congruent SSEP changes. In 13 patients (23.2%), ischemic changes in MEPs were reversed by reimplanting segmental arteries or increasing blood flow or blood pressure. None of these 13 patients suffered acute paraplegia regardless of the status of SSEP at the end of the procedure, but 1 of them developed delayed postoperative paraplegia after multisystem failure. Three patients (5.4%) who had persistent loss of MEPs despite of recovery of SSEPs awoke paraplegic. CONCLUSIONS The results demonstrate that compared with SSEP, MEP, especially myogenic MEP, is more sensitive and specific in detection of spinal cord ischemia, and that intraoperative monitoring can indeed help prevent paraplegia.
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Safety of intraoperative transcranial electrical stimulation motor evoked potential monitoring. J Clin Neurophysiol 2002; 19:416-29. [PMID: 12477987 DOI: 10.1097/00004691-200210000-00005] [Citation(s) in RCA: 239] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
This article reviews intraoperative transcranial electrical stimulation (TES) motor evoked potential (MEP) monitoring safety based on comparison with other clinical and experimental brain stimulation methods and clinical experience in more than 15000 cases. Comparative analysis indicates that brain damage and kindling are highly unlikely. There have been remarkably few adverse events. Pulse train TES-induced or coincidental seizures (n = 5) are rare, probably because of very brief (<0.03 second) stimuli, anesthesia, and the general absence of predisposing cerebral conditions. Soft bite blocks may prevent tongue or lip laceration (n = 29) or mandibular fracture (n = 1). Rare cardiac arrhythmia (n = 5) and intraoperative awareness (n = 1) may be coincidental. Minor scalp burns (n = 2) are rare. Although possible, no spinal epidural recording electrode complications or injuries resulting from TES-induced movement were found. There have been no recognized adverse neuropsychological effects, headaches, or endocrine disturbances. Comprehensive relative contraindications include epilepsy, cortical lesions, convexity skull defects, raised intracranial pressure, cardiac disease, proconvulsant medications or anesthetics, intracranial electrodes, vascular clips or shunts, and cardiac pacemakers or other implanted biomedical devices. Otherwise unexplained intraoperative seizures and possibly arrhythmias are indications to abort TES. With appropriate precautions in expert hands, the well-established benefits of TES MEP monitoring decidedly outweigh the associated risks.
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An approach to intraoperative neurophysiologic monitoring of thoracoabdominal aneurysm surgery. J Clin Neurophysiol 2002; 19:43-54. [PMID: 11896352 DOI: 10.1097/00004691-200201000-00006] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Thoracoabdominal aneurysm surgery carries an approximate 10% risk of intraoperative paraplegia. Abrupt cord ischemia and the confounding effects of systemic alterations and limb or cerebral ischemia challenges neurophysiologic spinal cord monitoring. This investigation sought a rapid differential monitoring approach to predict or help prevent paraplegia. Thirty-one patients were monitored with motor evoked potentials (MEPs) and median and tibial somatosensory evoked potentials (SSEPs). MEPs involved single-pulse transcranial electrical stimulation with D wave recording (n = 16), arm and leg muscle MEPs following multiple-pulse transcranial electrical stimulation (n = 12), or both (n = 3). D wave recordings required averaging, invasive epidural electrode insertion, and produced both false positives and false negatives. Muscle MEPs were instantaneous and reliably sensitive and specific for cord ischemia. Cortical and peripheral nerve SSEPs provided rapid detection of systemic alterations and cerebral or limb ischemia. Cord and subcortical SSEPs required excessive averaging time. In conclusion, bilateral arm and leg muscle MEPs with median and tibial peripheral nerve and cortical SSEPs provide sufficiently rapid detection and differentiation of cord ischemia from confounding factors. There were two predicted intraoperative spinal cord infarctions (6.5%) and nine circumstantial examples of possible contributions to deficit prevention.
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Individually optimizing posterior tibial somatosensory evoked potential P37 scalp derivations for intraoperative monitoring. J Clin Neurophysiol 2001; 18:364-71. [PMID: 11673702 DOI: 10.1097/00004691-200107000-00008] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
This investigation sought the optimal (highest amplitude) derivation for monitoring the posterior tibial P37 for each side in each individual, and determined whether this may change intraoperatively. Fifty monitored patients were studied using a partial P37 map consisting of FPz, Fz, Cz, Cz', Pz, POz, C4', and C3' to a noncephalic reference. From this, the highest amplitude scalp derivation was determined for each side. Of 100 tibial nerves, the initial optimal input 1 was Cz' in 52%, Pz in 28%, and Cz or iC' in 10%, and optimal input 2 was cC' in 69% and FPz in 31%. The optimal derivation was the same for each side in 34% of patients and different in 66%. Of 31 patients with at least one subsequent trial later during surgery, P37 topography changed in 14 and affected optimal inputs in 12. This occurred regularly during sitting-position posterior fossa surgery because of intracranial air, but sometimes occurred during other surgeries as well. The most common change consisted of FPz replacing cC' as optimal input 2. Input 1 changes were predominantly in an anterior or posterior sagittal direction. The results demonstrate great inter- and intraindividual P37 variability, and document intraoperative topographic changes. Both phenomena can be addressed by a practical method to refine intraoperative monitoring by individually optimizing scalp derivations and identifying topographic P37 changes during surgery.
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Intraoperative electrocorticography in temporal lobe epilepsy surgery. Can J Neurol Sci 2000; 27 Suppl 1:S85-91; discussion S92-6. [PMID: 10830334 DOI: 10.1017/s031716710000072x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Although in clinical use for many years, the validity of intraoperative electrocorticography (ECoG) in guiding resective temporal lobe epilepsy (TLE) surgery is uncertain. Advances in neuroimaging and extraoperative intracranial recordings have contributed greatly to the identification of epileptogenic lesions and cortex, clarifying the limitations of a brief intraoperative interictal recording. Studies of undifferentiated ECoG findings (which classify all interictal cortical spike discharges as equal) tend to not support this method. This article reviews ECoG and presents data from 86 TLE surgeries at the University of British Columbia suggesting that differentiation of ECoG features may enhance the contribution of this time honored method. Specifically, independent foci may be more important for epileptogenesis than synchronous foci, and postexcision activation appears to be a benign phenomenon, while residual spikes unaltered by the resection correlate with a greater proportion of seizure recurrence.
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Selective shunting with EEG monitoring is safer than routine shunting for carotid endarterectomy. CARDIOVASCULAR SURGERY (LONDON, ENGLAND) 1997; 5:481-5. [PMID: 9464604 DOI: 10.1016/s0967-2109(97)00044-6] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The purpose of this study was to identify whether EEG is an adequate method of monitoring cerebral perfusion during carotid endarterectomy and of determining the need for use of an indwelling shunt. A retrospective review of 305 carotid endarterectomies comparing the results of routinely shunted patients with patients selectively shunted based on EEG monitoring, was carried out. Of the carotid endarterectomies, 92 (30%) were routinely shunted and 213 (70%) were selectively shunted. In the selectively shunted group, 34 (16%) subsequently required shunting. The major stroke rate in the routinely shunted group was 4.4% ((4) cases) and in the selectively shunted group was 0.5% ((1) stroke). Three of the four major strokes in the routinely shunted group were embolic in origin and one was caused by acute thrombosis. The only major stroke in the selectively shunted group was from intracerebral hemorrhage. In conclusion EEG monitoring is a safe and reliable method to determine the need for shunting during carotid endarterectomy. Routine non-selective use of a shunt may increase the risk of perioperative stroke from arterial injury and associated thromboembolism.
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Abstract
An immunoperoxidase method was used to demonstrate expression of HLA-DR (a Class II major histocompatibility antigen) as an indicator of microglial activation in cases of hippocampal sclerosis derived from temporal lobectomy for intractable seizures. HLA-DR-immunoreactive microglia were increased approximately 11-fold in CA1 and 3-fold in CA3, compared to control autopsy hippocampus. The numbers of HLA-DR-immunoreactive perivascular cells were also significantly increased in hippocampal sclerosis cases (9-, 7- and 6-fold increases in CA1, CA3 and CA2, respectively). Since animal studies have found microglial activation to be an acute or subacute response to injury, the results presented here suggest that, contrary to the classical conception of human hippocampal sclerosis as an inert scar, neuronal injury continues to occur as a result of ongoing seizure activity.
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