The Effect of Epidural Injection of Betamethasone or Bupivacaine in a Rat Model of Lumbar Radiculopathy

Abstract

Epidural steroid injection has a significant effect on the thermal hyperalgesia produced in a model of radiculopathy, which may provide clinical support for advocates of epidural steroids.

Epidural Local Anesthetic Plus Corticosteroid for the Treatment of Cervical Brachial Radicular Pain: Single Injection Versus Continuous Infusion

“…29 The observed efficacy of these drugs is probably related to their multiple short-term effects including anti-inflammatory and immunosuppressive activity, 3,8,[15][16][17] and the probable inhibition of neurotransmission within C-fibers. 17 In the present study, methylprednisolone seems to be effective in the treatment of acute and subacute pain (T 1 to T 3 ).…”

“…3,4,[11][12][13][14] Most studies agree that epidural corticosteroids provide a certain level of efficacy in the treatment of cervicobrachial and back pain. The observed efficacy of corticosteroids for these syndromes has been suggested to relate to their antiedema effect and anti-inflammatory and immunosuppressive actions 4,15,16 in addition to the probable inhibition of neurotransmission within C-fibers. 17 On the contrary, the efficacy of the epidural local anesthetics is still unclear.…”

“…4,15,18 However, local anesthetic has also been used to obtain immediate shortterm symptomatic relief without determining efficacy for the treatment of chronic pain. 14 Few are the studies that report the use of local anesthetic through continuous infusion (continuous epidural local anesthetic) and even in those studies the local anesthetic is not considered as a ''curative'' drug, but is merely used as a symptomatic, effective during the short periods of the infusion.…”

Epidural steroids

“…Another animal model of radiculopathy was employed by Hayashi et al [4]. Thirty-six rats underwent loose suture ligation of the left L4 and L5 nerve roots, followed immediately by placement under direct visualization of an epidural catheter with the tip between the ligated nerve roots.…”

“…Thirty-six rats underwent loose suture ligation of the left L4 and L5 nerve roots, followed immediately by placement under direct visualization of an epidural catheter with the tip between the ligated nerve roots. Motor function, thermal withdrawal latency, and mechanical withdrawal thresholds were determined prior to surgery, at multiple time points in the 48 hours after surgery, and on days 4,7,11,14,21,35,42, and 49. On postoperative day 3, nine rats received epidural injection of 0.3 mg/ kg betamethasone in 0.1 mL of normal saline, eight received 0.1 mL of normal saline, six received betamethasone plus 0.1 mL of 0.25% bupivacaine, and six received 0.1 mL of 0.25% bupivacaine.…”