Of late,
regional anesthesia has enjoyed unprecedented popularity; this increase in cases has brought a higher frequency of instances of neurological deficit and
arachnoiditis that may appear as transient nerve root irritation, cauda equina, and
conus medullaris syndromes, and later as
radiculitis, clumped nerve roots,
fibrosis,
scarring dural sac
deformities,
pachymeningitis, pseudomeningocele, and
syringomyelia, etc., all associated with
arachnoiditis.
Arachnoiditis may be caused by
infections, myelograms (mostly from oil-based
dyes), blood in the intrathecal space, neuroirritant, neurotoxic and/or neurolytic substances, surgical interventions in the spine, intrathecal
corticosteroids, and
trauma. Regarding
regional anesthesia in the neuroaxis,
arachnoiditis has resulted from epidural
abscesses, traumatic
punctures (blood),
local anesthetics,
detergents,
antiseptics or other substances unintentionally injected into the spinal canal. Direct
trauma to nerve roots or the spinal cord may be manifested as paraesthesia that has not been considered an injurious event; however, it usually implies dural penetration, as there are no nerve roots in the epidural space posteriorly. Sudden severe
headache while or shortly after an epidural block using the loss of resistance to air approach usually suggests
pneumocephalus from an intradural injection of air. Burning severe
pain in the lower back and lower extremities,
dysesthesia and
numbness not following the usual dermatome distribution, along with bladder, bowel and/or sexual dysfunction, are the most common symptoms of direct
trauma to the spinal cord. Such patients should be subjected to a neurological examination followed by an MRI of the effected area. Further spinal procedures are best avoided and the prompt administration of IV
corticosteroids and
NSAIDs need to be considered in the hope of preventing the inflammatory response from evolving into the proliferative phase of
arachnoiditis.