Clonidine in lumbar sympathetic block for lower limb complex regional pain syndrome

Abstract EN

Background Complex regional pain syndrome (CRPS) is a condition of continuing (spontaneous and / or evoked) limb pain.

The pain is nondermatomal and usually has a distal predominance of abnormal sensory, motor, sudomotor, vasomotor, and/or trophic fi ndings.

Sympathetic nerve blockade of the upper and lower extremities using a local anesthetic and corticosteroids is one of the modalities in the treatment of severe, sympathetically mediated pain.

This randomized controlled trial studies the effect of adding clonidine to levobupivacaine in repeated lumbar sympathetic blocks for patients suffering from lower limb CRPS type 1.

Methods Thirty patients of ASA physical status I and II having CRPS-1 in the lower limb were enrolled.

All patients underwent lumbar sympathetic block as treatment.

They were assigned to one of two groups comprising 15 patients each.

Group A patients were injected with 20 ml of levobupivacaine (0.5%) +8 mg dexamethasone (2 ml)+150 μg (1 ml) clonidine.

Group B patients were injected with 20 ml of levobupivacaine (0.5%)+8 mg dexamethasone (2 ml)+saline (1 ml).

Patients were seen in the clinic every week for 6 weeks.

During each follow-up visit, edema score (grades 0–2) and range of motion at knee and ankle joints (grades 0–2) were assessed.

Repeated blocks by the same technique were performed with a maximum of fi ve blocks for each patient over a period of 6 weeks.

Repetition of blocks was dependent on exacerbation of pain if visual analogue scale (VAS) score was greater than 50.

The number of blocks needed during the 6-week period in each group was recorded.

Side effects after each block, such as hypotension, bradycardia, and backache, were recorded.

At 6 weeks, all patients were asked to fi ll out a satisfaction score (grades 0–10).

Results Intergroup comparison showed that the VAS score was lower in group A than in group B, but there was no statistically signifi cant difference between them except in the fi fth week.

Within-group comparison revealed a statistically signifi cant decrease in the two groups in the 6 weeks in the measured VAS score compared with the baseline VAS scores.

There was improvement in edema and motion in the two groups throughout the 6 weeks, but there was no statistically signifi cant difference between the two groups.

There was a statistically signifi cant difference between the two studied groups as regards the number of blocks, where group A had a fewer blocks compared with group B.

Patients in group A were signifi cantly more satisfi ed after the 6 weeks compared with patients in group B.

Conclusion Adding clonidine to levobupivacaine and steroids in repeated lumbar sympathetic blocks for patients suffering from lower limb CRPS type 1 prolongs analgesia and improves edema and tolerability to physical therapy.