Academic Neurosurgery Unit, St. George's, University of London, London, UK.
Neuroanaesthesia/Neuro Intensive Care, St. George's Hospital, London, UK.
Neurocrit Care. 2021 Feb;34(1):121-129. doi: 10.1007/s12028-020-00988-2.
BACKGROUND/OBJECTIVE: We have recently developed monitoring from the injury site in patients with acute, severe traumatic spinal cord injuries to facilitate their management in the intensive care unit. This is analogous to monitoring from the brain in patients with traumatic brain injuries. This study aims to determine whether, after traumatic spinal cord injury, fluctuations in the monitored physiological, and metabolic parameters at the injury site are causally linked to changes in limb power.
This is an observational study of a cohort of adult patients with motor-incomplete spinal cord injuries, i.e., grade C American spinal injuries association Impairment Scale. A pressure probe and a microdialysis catheter were placed intradurally at the injury site. For up to a week after surgery, we monitored limb power, intraspinal pressure, spinal cord perfusion pressure, and tissue lactate-to-pyruvate ratio. We established correlations between these variables and performed Granger causality analysis.
Nineteen patients, aged 22-70 years, were recruited. Motor score versus intraspinal pressure had exponential decay relation (intraspinal pressure rise to 20 mmHg was associated with drop of 11 motor points, but little drop in motor points as intraspinal pressure rose further, R = 0.98). Motor score versus spinal cord perfusion pressure (up to 110 mmHg) had linear relation (1.4 motor point rise/10 mmHg rise in spinal cord perfusion pressure, R = 0.96). Motor score versus lactate-to-pyruvate ratio (greater than 20) also had linear relation (0.8 motor score drop/10-point rise in lactate-to-pyruvate ratio, R = 0.92). Increased intraspinal pressure Granger-caused increase in lactate-to-pyruvate ratio, decrease in spinal cord perfusion, and decrease in motor score. Increased spinal cord perfusion Granger-caused decrease in lactate-to-pyruvate ratio and increase in motor score. Increased lactate-to-pyruvate ratio Granger-caused increase in intraspinal pressure, decrease in spinal cord perfusion, and decrease in motor score. Causality analysis also revealed multiple vicious cycles that amplify insults to the cord thus exacerbating cord damage.
Monitoring intraspinal pressure, spinal cord perfusion pressure, lactate-to-pyruvate ratio, and intervening to normalize these parameters are likely to improve limb power.
背景/目的：我们最近开发了一种从急性严重创伤性脊髓损伤患者的损伤部位进行监测的方法，以方便在重症监护病房对其进行管理。这类似于对创伤性脑损伤患者从脑部进行监测。本研究旨在确定在创伤性脊髓损伤后，损伤部位监测到的生理和代谢参数的波动是否与肢体力量的变化有因果关系。
这是一项对患有运动不完全性脊髓损伤的成年患者队列的观察性研究，即美国脊髓损伤协会损伤分级 C 级。在损伤部位硬膜内放置压力探头和微透析导管。在手术后的一周内，我们监测了肢体力量、椎管内压力、脊髓灌注压和组织乳酸/丙酮酸比值。我们建立了这些变量之间的相关性，并进行了格兰杰因果关系分析。
共招募了 19 名年龄在 22-70 岁的患者。运动评分与椎管内压力呈指数衰减关系（椎管内压力升高 20mmHg 与运动评分下降 11 分相关，但椎管内压力进一步升高时运动评分下降较小，R=0.98）。运动评分与脊髓灌注压（高达 110mmHg）呈线性关系（脊髓灌注压升高 10mmHg 时运动评分升高 1.4 分，R=0.96）。运动评分与乳酸/丙酮酸比值（大于 20）也呈线性关系（乳酸/丙酮酸比值升高 10 分时运动评分下降 0.8 分，R=0.92）。椎管内压力升高引起乳酸/丙酮酸比值升高、脊髓灌注下降和运动评分下降。脊髓灌注压升高引起乳酸/丙酮酸比值下降和运动评分升高。乳酸/丙酮酸比值升高引起椎管内压力升高、脊髓灌注下降和运动评分下降。因果关系分析还揭示了多个恶性循环，这些循环放大了对脊髓的损伤，从而加重了脊髓损伤。
监测椎管内压力、脊髓灌注压、乳酸/丙酮酸比值，并干预以使其正常化，可能会改善肢体力量。
