Lumbar cerebrospinal fluid pulse wave rising from pulsations of both the spinal cord and the brain in humans

Abstract

There are two theories regarding the origin of the lumbar cerebrospinal¯uid pulse wave (L-CSFPW): that it arises from the arteries supplying the spinal cord, and that it is due to the pulsations of the brain transmitted through the subarachnoid space of the spine.We investigated L-CSFPW of 11 myelopathic patients with a complete (®ve patients, CBgroup) or an incomplete spinal block (six, ICB-group) on myelography to determine the origin of L-CSFPW. Since arterial pressure amplitude (APA), the energy source of L-CSFPW, is not the same between individuals or between before and after operation, not only L-CSFPW itself but also the transfer function between the arterial pressure wave and the L-CSFPW calculated by the system analysis method was analyzed to eliminate the in¯uence of hemodynamic uctuations. In the system analysis, the arterial pressure wave, L-CSFPW and transfer function were decomposed into ®ve harmonic waves (HW).In the CB group, L-CSFPW was observed to be 0.72 mmHg on average (range, 0.25 ± 1.00) in spite of blocking pulsations of the brain, showing that there was a contribution to L-CSFPW unrelated to the brain, that is, the spinal cord. In the CB group, however, the preoperative transfer function value of HW1 (mean, 0.056; range, 0.012 ± 0.170) was lower than that in the ICB group (mean, 0.137; range, 0.061 ± 0.236) (P50.05), indicating that the brain pulsation also contributed to L-CSFPW.In the ICB group, there was signi®cant reduction of HW1 (P50.01) and HW2 (P50.05) transfer function after posterior decompression surgery in spite of improvement in the subarachnoid space narrowing: preoperative HW1, mean, 0.137, range, 0.061 ± 0.236; postoperative HW1, mean, 0.065, range, 0.021 ± 0.153; preoperative HW2, mean, 0.092, range, 0.011 ± 0.148; postoperative HW2, mean, 0.044, range, 0.030 ± 0.066. It has been reported that the spinal cord blood¯ow is decreased 20% or more by laminectomy, therefore, L-CSFPW measurement may be sensitive enough to detect a 20% or higher decrease in this ow. This suggests that L-CSFPW could possibly be used clinically as a non-invasive method of monitoring the spinal cord blood¯ow. For broad clinical application of CSFPW, however, further studies are needed, especially on the direct relationship between CSFPW and spinal cord blood¯ow itself.

A lumped-parameter model of the cerebrospinal system for investigating arterial-driven flow in posttraumatic syringomyelia

“…However, in the real anatomy spinal arteries connect to the cardiovascular system not only through the vertebral anastomosis but also directly from arteries such as the radicularis magna branching from the aorta [35], so arterial blood flow is not limited to the rostrocaudal direction and neither is venous return. This branched network of blood vessels will provide distributed excitation to the SC tissues as well as the fluid and surrounding tissues of the SSS, all of which will contribute to the spinal CSF pulse wave, as will CSF pulsations transmitted from the head [6,[9][10][11]. In simulations where c Vasc,SC was changed from zero in increments up to c Vasc,SSS the main effect was a phase shift of p (not shown).…”

“…The cardiac cycle sets up a spinal CSF pulse wave, generated by spinal arterial pulsations, spinal venous pulsations and the intracranial CSF pulse wave transmitted through the spinal canal [6,[9][10][11]. The relative contributions of these sources is a moot point though; a study using direct pressure measurements on canines placed the values at approximately 40%, 40% and 20%, respectively [9], while a phase-contrast MRI study on humans suggested that the intracranial CSF pulsations may play a more prominent role [6].…”

Dural port therapy

“…SOT can evaluate the condition of meningeal tension (3,4,6,7,9) which is associated with the flexion/inhalation and extension/exhalation phase of the primary respiratory motion. When the meninges, neural tissues, and specifically the spinal dura are fixated in flexion or extension it is theorized that this could affect lumbar cerebrospinal fluid fluctuations (3,(37)(38)(39)(40).…”

The Effects of Prehydration on the Properties of Cerebrospinal Fluid and the Spread of Isobaric Spinal Anesthetic Drug

“…The definitions of the parameters are as follows: stroke volume (mL); average of the CSF volume moving caudally during systole and cephalically during diastole, regurgitant fraction (%); the ratio of caudal to cranial flow of the CSF per single stroke volume, absolute stroke volume (mL); the integral over time for the volumetric flow rate, and flux (mL/s); "mean velocity ϫ area" or the CSF volume that passes the contour per second. 11,12,19 Two radiologists, who were blinded to the aims of this study, manually placed circular ROIs in triplicate at different sessions for each sample, respectively, and obtained the mean values of the circular ROIs. Analysis and data post-processing were performed at a workstation, and the measured signal changes were converted to a velocity, and the amount of flow was determined using an analysis program (View Forum, Philips Medical System, Best, The Netherlands).…”

“…9 -11 In addition to this pump flow mechanism, spinal vascular pulsations are considered to be the origin of spinal CSF pulsation in more complex ways. 8,12 We hypothesized that the rapid prehydration of relatively large amounts of crystalloid would affect the physical properties of the CSF such as flow and oscillatory motion which, in turn, would influence the spread of local spinal anesthetics in the intrathecal space. A two-stage study was designed to test this hypothesis.…”