Detrimental effects of cerebrospinal fluid pressure elevation on spinal cord perfusion: first-time direct detection in a large animal model

Abstract

OBJECTIVES Cerebrospinal fluid (CSF) drainage is routinely utilized to mitigate perioperative and postoperative spinal cord ischaemia in open and endovascular thoraco-abdominal aortic aneurysm repair to prevent permanent paraplegia. Clinical decision-making in the vulnerable perioperative period, however, is still based on limited clinical and experimental data. Our aim was to investigate the isolated effect of CSF pressure elevation on spinal cord perfusion in an established large animal model. METHODS Ten juvenile pigs with normal (native) arterial inflow (patent segmental arteries and collaterals) underwent iatrogenic CSF pressure elevation (×2, ×3, ×4 from their individual baseline pressure). Each pressure level was maintained for 30 min to mimic clinical response time. After the quadrupling of CSF pressure, the dural sac was slowly depressurized against gravity allowing CSF pressure to passively return to baseline values. Measurements were taken 30 and 60 min after normalization, and microspheres for regional blood flow analysis were injected at each time point. RESULTS Spinal cord perfusion decreased significantly at all mid-thoracic to lumbar cord segments at the doubling of CSF pressure and declined to values <53% compared to baseline when pressure was quadrupled. Normalizing CSF pressure led to an intense hyperperfusion of up to 186% at the cervical level and 151% within the lumbar region. CONCLUSIONS CSF pressure elevation results in a relevant impairment of spinal cord blood supply. Close perioperative and postoperative monitoring of CSF pressure is crucial for maintaining sufficient spinal cord perfusion. Radical and rapid withdrawal of CSF is followed by significant hyperperfusion in all spinal cord segments and may lead to ‘drainage-related’ iatrogenic reperfusion injury—aggravating the risk of delayed spinal cord injury—and should therefore be avoided.

Subacute Posttraumatic Ascending Myelopathy After Thoracolumbar Spinal Cord Injury

“…The changes observed on MRI may not correlate with clinical findings at follow-up 9 . MRI to date remains the gold standard for the diagnosis of SPAM; however, the use of computed tomography scan 8 , Cerebrospinal fluid (CSF) examination 2,6,8,24 , lumbar puncture 2,6,8,24 , myelography 2,28 , and selective spinal angiography 6,9 have been reported.…”

“…Surgical decompression was performed to reduce the increased CSF pressure with an attempt at SPAM resolution in 2 cases in accordance with the CSF flow alteration hypothesis in SPAM 12,18 . Yablon et al 28 suggested early surgical decompression after the initial SCI could prevent SPAM. Okada et al 14 proposed laminectomy with a pial incision.…”

“…The hypothesis of cerebrospinal fluid (CSF) flow alteration was supported by many authors 10,12,14 . CSF pressure elevation results in spinal cord blood supply impairment and subsequent SCI 28 . Meagher et al 12 suggested that intramedullary hemorrhage, edema, and debris, which occurred after an injury, could occlude the central canal drainage and lead to elevated CSF pressure.…”

Commentary: Going transesophageal will make your monitoring simpler!

“…2 As SCI entails devastation, laboratory and animal research aimed at developing strategies to control its risks is ongoing. 3,4 Neurophysiological monitoring has obviously received much attention for some 3 decades now, and much research has been devoted to identifying the ideal monitoring system, which theoretically should be able to identify ischemia in the shortest period and recognize the efficacy of reperfusion after surgical maneuvering. Transcranial motor-evoked potential (TC-MEP) monitoring is currently the most reliable technique in the clinical setting and provides more rapid information during ischemia and fewer false-positive results for reperfusion compared with somatosensory evoked potentials (SSEPs).…”

“… 2 As SCI entails devastation, laboratory and animal research aimed at developing strategies to control its risks is ongoing. 3 , 4 …”