Methodology of Motor Evoked Potentials in a Rabbit Model
- PDF / 870,892 Bytes
- 8 Pages / 595.276 x 790.866 pts Page_size
- 68 Downloads / 193 Views
ORIGINAL ARTICLE
Methodology of Motor Evoked Potentials in a Rabbit Model Stephen D. Waterford 1 & Michelle Rastegar 1 & Erin Goodwin 2 & Paul A. Lapchak 3 & Viviana Juan 1 & Farnaz Haji 1 & René Bombien 1 & Ali Khoynezhad 1
Received: 6 August 2014 / Revised: 22 April 2015 / Accepted: 12 May 2015 / Published online: 20 May 2015 # Springer Science+Business Media New York 2015
Abstract Spinal cord ischemia (SCI) is a devastating complication of aortic operations. Neuromonitoring using motor evoked potentials (MEPs) is a sensitive modality to detect SCI in humans. We describe a leporine SCI model using MEPs to test pharmaceutical therapeutics and other neuroprotective adjuncts. In 80 rabbits, methods to obtain MEPs in normotensive and ischemic rabbits were developed. The effects of isoflurane, propofol, apnea, and hypotension on lower extremity MEPs were studied. Lower extremity MEPs disappear upon SCI induction in 78 of 78 (100 %) rabbits. Prior to SCI induction and during apneic episodes, lower extremity MEPs were lost in all (100 %) and upper extremity MEPs in one (25 %). Isoflurane was used in four experiments, with loss of lower extremity MEPs in all four (100 %) and loss of upper extremity MEPs in zero. With propofol upper extremity, MEPs were obtainable in 80 of 80 rabbits (100 %) and lower extremity MEPs in 78 of 80 rabbits (97.5 %) prior to SCI induction. The presence of these lower extremity MEPs prior to SCI induction was not correlated with systolic or diastolic blood pressure. Disappearance of MEPs occurred in all 45 rabbits with postoperative lower extremity impairment. MEPs in the leporine model correlate closely with paraplegia. MEPs are influenced by inhaled anesthetics and apnea but not by hypotension alone. Propofol anesthesia provides reliable
* Ali Khoynezhad [email protected] 1
Division of Cardiothoracic Surgery, Cedars-Sinai Medical Center, 127 S. San Vicente Blvd., Suite 3306, Los Angeles, CA 90048, USA
2
Comparative Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA
3
Department of Neurology and Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, CA, USA
MEPs. This study provides the basis for a reproducible model of SCI to be used for novel therapeutic drug development. Keywords Neuromonitoring . Motor evoked potential . Spinal cord ischemia . Paraplegia . Rabbit . Thoracic aortic
Introduction Spinal cord ischemia (SCI) leading to paraplegia or paraparesis is a devastating complication of aortic surgery. The risk of SCI ranges from 2 to 14 % in endovascular and open surgical treatment of aortic disease [1–3]. To detect SCI, neuromonitoring of transcranial motor evoked potentials (MEPs) is used during aortic surgery [4]. MEP disappearance indicates that ischemia has occurred and prompts corrective action [4]. MEPs record the electrical responses of muscles following stimulation of the motor cortex with scalp electrodes. While MEPs are standard of care in many hospitals, incorporation of MEP in animal models of SCI, while reported, has been scarce [5, 6]. Neuroprotec
Data Loading...
