The origin of the spinal subdural space: ultrastructure findings.
ABSTRACT Previous studies of samples from cranial meninges have created doubts about the existence of a virtual subdural space. We examined the ultrastructure of spinal meninges from three human cadavers immediately after death to see whether there is a virtual subdural space at this level. The arachnoid mater had two portions: a compact laminar portion covering the dural sac internal surface and a trabecular portion extending like a spider web around the pia mater. There was a cellular interface between the laminar arachnoid and the internal layer of the dura that we called the dura-arachnoid interface. There was no subdural space in those specimens where the dura mater was macroscopically in continuity with the arachnoid trabecules. In the specimens where the dura mater was separated from the arachnoid, we found fissures in between the neurothelial cells that extended throughout the interface. We hypothesize that the subdural space would have its origin within the dura-arachnoid interface when the neurothelial cells break up, creating in this way a real subdural space. IMPLICATIONS: The subdural space was not seen under transmission electron microscopy in samples of human spinal meninges where surgical manipulation was avoided. Scanning electron microscopy in other samples showed the presence of broken neurothelial cells giving up fissures that extended along the dura-arachnoid interface. These findings may explain the origin of a real subdural space.
Article: Dural puncture and subdural injection: a complication of lumbar transforaminal epidural injections.[show abstract] [hide abstract]
ABSTRACT: Two cases are presented in which the complication of dural puncture is documented in the context of a lumbar transforaminal epidural steroid injection. The hazard of dural puncture during transforaminal epidural injections, the anatomy of the dural and thecal sac, the potential for subdural injections, and relevant literature are reviewed. Report of two cases. Lumbar transforaminal epidural steroid injections are a commonly employed procedure for the treatment of lumbar radiculopathy. The optimal target point lies at the "6 o' clock" position of the pedicle. Contrast is injected to confirm proper placement of the needle and correct flow of the medication through the epidural space. Despite apparent proper placement of the needle, a potential complication exists of puncturing the dura while performing this procedure. Spinal injectionists should recognize the subsequent contrast patterns associated with this complication. Subdural and intrathecal spread of contrast is rarely seen with transforaminal injections and thus can be easily overlooked. Becoming familiar with the images presented in these cases may help alert the interventionalist of a dural puncture, and thus avoid injection of medications into the intrathecal and subdural spaces.Pain physician 10/2007; 10(5):697-705. · 10.72 Impact Factor
Article: Subdural block and the anaesthetist.[show abstract] [hide abstract]
ABSTRACT: There are a number of case reports describing accidental subdural block during the performance of subarachnoid or epidural anaesthesia. However it appears that subdural drug deposition remains a poorly understood complication of neuraxial anaesthesia. The clinical presentation may often be attributed to other causes. Subdural injection of local anaesthetic can present as high sensory block, sometimes even involving the cranial nerves due to extension of the subdural space into the cranium. The block is disproportionate to the amount of drug injected, often with sparing of sympathetic and motor fibres. On the other hand, the subdural deposition can also lead to failure of the intended block. The variable presentation can be explained by the anatomy of this space. High suspicion in the presence of predisposing factors and early detection could prevent further complications. This review aims at increasing awareness amongst anaesthetists about inadvertent subdural block. It reviews the relevant anatomy, incidence, predisposing factors, presentation, diagnosis and management of unintentional subdural block during the performance of neuraxial anaesthesia.Anaesthesia and intensive care 01/2010; 38(1):20-6. · 1.28 Impact Factor
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ABSTRACT: Several cases of accidental subdural injection have been reported, but only few of them are known to be accidental intradural injection during epidural block. Therefore we would like to report our experience of accidental intradural injection. A 68-year-old female was referred to our pain clinic due to severe metastatic spinal pain. We performed a diagnostic epidural injection at T9/10 interspace under the C-arm guided X-ray view. Unlike the usual process of block, onset was delayed and sensory dermatomes were irregular range. We found out a dense collection of localized radio-opaque contrast media on the reviewed X-ray findings. These are characteristic of intradural injection and clearly different from the narrow wispy bands of contrast in the subdural space.Korean journal of anesthesiology 03/2011; 60(3):205-8.