Resin Injection Studies of the Lumbar Extradural Space

Abstract

Two resin injection studies of the lumbar extradural space were performed to elucidate its size and shape. To counteract the lack of cerebrospinal fluid pressure in the cadaver, the subarachnoid space was filled with water. In group 1, the extradural injection of resin caused an immediate increase in subarachnoid pressure. The casts produced varied in thickness, but were situated predominantly in the dorsomedial and dorsolateral regions of the spinal canal. Thin anterior spread occurred in 40% of cases. In group 2, resin was injected to the subarachnoid space before the extradural injection of dyed resin. The resulting extradural casts were thinner than in group 1, but the distribution of resin was similar. The problems of interpreting resin casts are discussed in relation to the results obtained, with reasons for suggesting that the extradural space is only potential.

Study of the Anatomy of the Extradural Region Using Magnetic Resonance Imaging

“…Cadaveric dissection [2] is subject to distortion because of postmortem autolysis and preservation with agents that alter tissue properties; furthermore, the loss of cerebrospinal fluid (CSF) pressure at death and possible increase in venous pressure result in changes in the relative volumes occupied by the dural sac and venous plexuses within the spinal canal. All techniques requiring the injection of fluid or air into the extradural region distort the anatomy; such methods have included resin injection studies [3], extradurography and computed tomography (CT) extradurography [4], extraduroscopy [5] and spinaloscopy [6]. More recently, a study using cryomicrotome sectioning of cadavers has provided some detailed information less distorted by artefact [7]-Magnetic resonance imaging (MRI) is the most rapidly advancing of the imaging specialties.…”

Spread of radioopaque dye in the epidural space in infants

“…Resin injection studies of Harrison et al . (9) in autopsies of 20 cadavers found that flow of the resin formed a large posterior bulge with thin anterolateral projections on either side. Anterior spread was seen only in eight out of 20 cases as very thin and incomplete.…”

“…Savolaine et al . (10) described a central midline structure called plica mediana dorsalis with the dorsolateral ligaments issuing from it (9,16), of which four patterns have been described. Many cases of unilateral spread have been attributed to this (16,21).…”

“…Epidural anaesthesia has been a part of paediatric anaesthesia for nearly two decades, but the calculation of the volume of injection is based more on a permissible limit of local anaesthetic dose than a specific volume to cover a specific number of dermatomes. The extent of spread of local anaesthetic solutions injected into the paediatric epidural space depends on many factors, such as the volume of injection (1–3), speed of injection (4,5), the back leak of the solution in the needle track around the catheter (3,5), leaks through intervertebral foramina (6,7), the pressures achieved in the epidural space (3,6–8) and the inherent divisions of the epidural space (9–17). We present a prospective study of the spread of two specific volumes of radioopaque dye injected into the epidural space in a controlled manner in 10 infants, to prove or disprove the hypothesis that the extent of spread of the dye would vary in direct proportion to the volume.…”

A study of epidural pressures in infants

“…One study (8) demonstrated a sustained rise in intracranial pressure in response to epidural injections. Another study of resin injections in the cadaver (9) has shown an intracisternal rise in pressure with concomitent lumbar epidural space injection. Measurement of the fontanelle pressures in infants would probably reflect any rise in CSF pressures due to a cephalad displacement.…”