AUTHOR=Bosscher Hemmo 

TITLE=Pressure-Volume Relationships in the Spinal Canal and Potential Neurological Complications After Epidural Fluid Injections

JOURNAL=Frontiers in Pain Research

VOLUME=Volume 3 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/pain-research/articles/10.3389/fpain.2022.884277

DOI=10.3389/fpain.2022.884277

ISSN=2673-561X

ABSTRACT=High volume fluid injections into the spinal canal may lead to severe neurological complications. But when anatomical or pathological conditions in the spinal canal are unfavorable, even small volume epidural injections can cause dangerously high epidural, subarachnoid and intra-cranial pressures or pressure gradients.  Data obtained from the scientific literature and from direct clinical observation are used to derive a first order approximation of epidural, subarachnoid and intracranial pressure responses to epidural fluid injections.   Maximum allowable fluid volumes for single or multiple divided fluid injections over time are calculated.  In the presence of spinal pathology, ten milliliters of fluids may increase epidural pressure to greater than 100 mmHg.  Injection speed greater than four milliliter per second may also generate dangerously high intra-spinal and intra-cranial pressures.  Intermittent bolus injections provide limited protection, but intraspinal pressures may rise very fast when a critical total injected volume is reached.  Potential complications of increased intracranial pressures or large pressure waves include nerve palsies, tinnitus, blindness, stroke and death.  Spinal injections or endoscopy should be performed in an awake responsive patient or with direct cerebrospinal fluid pressure monitoring.  A set of guidelines for epidural fluid management is given.