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. METHODS 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. RESULTS 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, R2 = 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, R2 = 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, R2 = 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. CONCLUSION Monitoring intraspinal pressure, spinal cord perfusion pressure, lactate-to-pyruvate ratio, and intervening to normalize these parameters are likely to improve limb power.

中文翻译：

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急性脊髓损伤：脊髓内压、脊髓灌注压、乳酸与丙酮酸的比率和肢体力量之间的相关性和因果关系。

背景/目的 我们最近开发了对急性、严重创伤性脊髓损伤患者的损伤部位进行监测，以促进他们在重症监护病房的管理。这类似于创伤性脑损伤患者的大脑监测。本研究旨在确定在创伤性脊髓损伤后，受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。方法 这是一项对一组患有运动不完全性脊髓损伤（即美国脊髓损伤协会损伤量表 C 级）的成年患者的观察性研究。压力探头和微透析导管被放置在损伤部位的硬膜内。手术后长达一周，我们监测肢体力量、椎管内压力、脊髓灌注压和组织乳酸与丙酮酸的比例。我们建立了这些变量之间的相关性并进行了格兰杰因果分析。结果 招募了 19 名年龄在 22-70 岁之间的患者。运动评分与椎管内压力呈指数衰减关系（椎管内压力上升至 20 mmHg 与 11 个运动点下降相关，但随着椎管内压力进一步上升，运动点几乎没有下降，R2 = 0.98）。运动评分与脊髓灌注压（最高 110 mmHg）呈线性关系（运动点升高 1.4 / 脊髓灌注压升高 10 mmHg，R2 = 0.96）。运动评分与乳酸/丙酮酸比（大于 20）也呈线性关系（运动评分下降 0.8/乳酸/丙酮酸比升高 10 分，R2 = 0.92）。脊柱内压增加 Granger 导致乳酸与丙酮酸比率增加、脊髓灌注减少和运动评分降低。脊髓灌注增加 Granger 导致乳酸与丙酮酸比值降低和运动评分增加。乳酸与丙酮酸的比率增加 Granger 导致椎管内压力增加、脊髓灌注减少和运动评分降低。因果关系分析还揭示了多个恶性循环，这些循环会放大对脐带的伤害，从而加剧脐带损伤。结论 监测脊柱内压、脊髓灌注压、乳酸与丙酮酸的比率，并进行干预以使这些参数正常化可能会改善肢体力量。脊髓灌注增加 Granger 导致乳酸与丙酮酸比值降低和运动评分增加。乳酸与丙酮酸的比率增加 Granger 导致椎管内压力增加、脊髓灌注减少和运动评分降低。因果关系分析还揭示了多个恶性循环，这些循环会放大对脐带的伤害，从而加剧脐带损伤。结论 监测脊柱内压、脊髓灌注压、乳酸与丙酮酸的比率，并进行干预以使这些参数正常化可能会改善肢体力量。脊髓灌注增加 Granger 导致乳酸与丙酮酸比值降低和运动评分增加。乳酸与丙酮酸的比率增加 Granger 导致椎管内压力增加、脊髓灌注减少和运动评分降低。因果关系分析还揭示了多个恶性循环，这些循环会放大对脐带的伤害，从而加剧脐带损伤。结论 监测脊柱内压、脊髓灌注压、乳酸与丙酮酸的比率，并进行干预以使这些参数正常化可能会改善肢体力量。因果关系分析还揭示了多个恶性循环，这些循环会放大对脐带的伤害，从而加剧脐带损伤。结论 监测脊柱内压、脊髓灌注压、乳酸与丙酮酸的比率，并进行干预以使这些参数正常化可能会改善肢体力量。因果关系分析还揭示了多个恶性循环，这些循环会放大对脐带的伤害，从而加剧脐带损伤。结论 监测脊柱内压、脊髓灌注压、乳酸与丙酮酸的比率，并进行干预以使这些参数正常化可能会改善肢体力量。