1987 Fiscal Year Final Research Report Summary
Evoked Spinal Cord Potential (ESP) for Detection and Prevention of Spinal Cord Ischemia During Aortic Cross-Clamping.
| Project/Area Number |
61480290
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Thoracic surgery
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| Research Institution | Hokkaido University. |
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Principal Investigator |
YASUDA Keishu Hokkaido University Hospital. Associate Professor., 医学部附属病院, 助教授 (60125359)
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| Co-Investigator(Kenkyū-buntansha) |
SAKUMA Makoto Hokkaido University Hospital. Instructor., 医学部附属病院, 助手 (70170636)
橋本 正人 北海道大学, 医学部, 助教授 (70002269)
TANABE Tatsuzo Hokkaido University, School of Medicine. Chief Professor., 医学部, 教授 (50000956)
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| Project Period (FY) |
1986 – 1987
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| Keywords | Thoracic aortic aneurysm / Aortic cross-clamping / Evoked spinal cord potential / Somato-sensory evoked potential / ESP / SEP / Spinal cord ischemia / 胸部大動脈瘤 |
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| Research Abstract |
Evoked spinal cord potential (ESP) was recorded and analyzed in order to detect and prevent the paraplegia caused by spinal cord ischemia during thoracic aortic cross-ciamping.
(1) Experiment.
Material and Methods: Adult dogs underwent continuous monitoring of ESP before, during, and after aortic cross-clamping. Stimulating electrodes were placed in the epidural space near L-1, sensing electrodes were placed in the intervertebral disc between T-3 and T-5. 5 to 100 responses were averaged to construct %e%sP..
Results: ESP responses to aortic cross-clamping were categorized into three types: loss of ESP during aortic cross-clamp (type 1),'no change in ESP during cross- clamp (type 2), and transient depression and return of ESP during cross-clamp (type 3). All dogs of type 1 response demonstrated paraplegia, where-as no dog of type 2 response showed paraplegia. Some dogs of type 3 response demonstrated spastic paraplegia. Although cross-clamp was removed 10 minutes after ESP became 20% of the previous amplitude in another series of type 1 dogs, paraplegia was not prevented.
Histological examination revealed infarction of the grey matter of the spinal cord below T-8 in the dogs with paraplegia.
Selective perfusion of the intercostal arteries furing cross-clamping and intraaortic infusion of vasodilators seemed promising to prevent spinal cord ischemic injury.
(2) Practice
ESP was monitored in 30 patients who underwent thoracic aortic surgery.
23 patients showed type 2 response. ESP was slightly depressed in 4 patients. 3 patients demonstrated type 1 response; temporary bypass was re-established in one case, cross-clamp could be released within a few minutes after ESP loss in other two cases. No paraplegia was experienced.
We have invented a special bypass tube to perfuse intercostal arteries during aortotomy in case of prolonged type 1 response which strongly suggests spinal cord ischemia.
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