Methylprednisolone reduces the early vascular permeability increase in spinal nerve roots induced by epidural nucleus pulposus application

Abstract

Autologous nucleus pulposus is known to have injurious effects on spinal nerve roots when applied epidurally. Both inflammatory and immunological mechanisms have been implicated in this regard. Various proinflammatory substances might be released or activated by nucleus pulposus and might affect the endoneural nerve root vessels. The present study assessed nucleus pulposus-induced early vascular reactions and the possibility of blocking these reactions with intravenous, high-dose, methylprednisolone pretreatment. In 25 pigs, the S2 and S3 nerve roots were exposed. In five pigs (control group), retroperitoneal fat was applied epidurally on the nerve roots, and the other 20 pigs had nucleus pulposus applied. This group was sub-divided into the treatment group (n = 8), in which the pigs were pretreated with intravenous high-dose methylprednisolone (30 mg/kg body weight), and the nontreatment group (n = 12), in which the pigs received a corresponding volume of saline solution. After 2 hours, Evans blue labeled albumin was injected intravenously 5 minutes before death. Endoneural extravasation of Evans blue labeled albumin was evaluated with fluorescence microscopy. A marked albumin leakage was found in 67% of the nontreated animals, in 25% of those in the treatment group, and in none of the control animals. These results demonstrate that nucleus pulposus can induce a rapid increase in endoneural vascular permeability in spinal nerve roots after epidural application. This increase can be partially prevented by pretreatment with high-dose methylprednisolone.

Proinflammatory cytokines in cerebrospinal fluid and serum in patients with disc herniation and sciatica

“…The mean IL-8 concentration in CSF in the control subjects was 25 pg/ml; the stroke patients showed a mean of 85 pg/ml at day 2 after onset, which decreased thereafter. The findings of a relatively acute inflammatory response in CSF after disc herniation supports previous experimental studies [3,16], and the low concentrations measured in serum indicate that this is a local response and not a systemic inflammatory reaction. No evidence for increased concentrations of TNF-α, IL-1β or IL-6 was found in serum or CSF.…”

“…The chemical influence has been linked to the leakage of substances from inner part of the disc, the nucleus pulposus (NP), after rupture of the annulus fibrosus [15,17]. Experimentally, the NP can induce an inflammatory-like reaction in and around the nerve root with increased vascular permeability, myelin changes, attraction of leukocytes and intravascular coagulation [3,13,17,28]. Inflammatory mediators such as cytokines, phospholipase A 2 and nitric oxide have been suggested to be important in the pathophysiology of NP-induced nerve root injury [2,12,16,18].…”

Two-Year Follow-Up Results of Fluoroscopic Cervical Epidural Injections in Chronic Axial or Discogenic Neck Pain: A Randomized, Double-Blind, Controlled Trial

“…While the underlying mechanism of action of epidurally administered local anesthetics and steroids is not clear, it is believed to be due to the antiinflammatory properties of corticosteroids 88-98. The evidence also indicates, however, that local anesthetics may have a similar effect to that of steroids 37,97-104.…”

Immediate Pain Response to Interlaminar Lumbar Epidural Steroid Administration: Response Characteristics and Effects of Anesthetic Concentration

“…The injected steroid has several putative actions on inflamed, sensitive tissue, including stabilization of cellular membranes, with reduced tissue and neural edema; a direct anti-inflammatory effect; inhibition of neural peptide synthesis/action; inhibition of prostaglandin synthesis; suppression of neuronal inflammatory discharges; suppression of sensitized dorsal horn neurons; and alteration of neuronal blood flow. [34][35][36][37][38][39][40][41][42] There is also a potential anti-inflammatory effect related to the injected local anesthetic that could complement or augment the steroid effect. 38,[43][44][45] Recently, interferon-␥ has been demonstrated in epidural lavage samples, and LESI response may equate to the level of interferon-␥ reduction.…”