Medication Summary
NSAIDs are mentioned not in this section because of the lack of any documented or studied effectiveness in piriformis syndrome. However, physicians may use any number of these agents, on the basis of their experience in managing LBP or neuropathies.
Naja et al investigated whether clonidine-bupivacaine nerve-stimulator guided injections are effective in achieving long-lasting pain relief in piriformis syndrome compared with bupivacaine guided injection. [16] Significantly lower pain scores and analgesic consumption were observed with bupivacaine-clonidine compared with bupivacaine-saline. Additionally, pain at 6 months was significantly greater in the bupivacaine-saline group (78%) compared with the bupivacaine-clonidine group (8%). [16]
Anesthetics
Class Summary
The drugs of choice for local injection in painful piriformis syndrome include the anesthetic agents lidocaine and/or bupivacaine. Both are in the family of amide anesthetics. Use is based on the desired duration of action. Doses, as described below, are intramuscularly (IM) administered by identifying the trigger point. Be sure to aspirate first to avoid injecting the medication into a blood vessel.
Lidocaine HCL (Xylocaine, Dilocaine, Anestacon)
Amide anesthetic that stabilizes neuronal membrane by inhibiting ionic fluxes. Absorbed completely with parenteral administration. Metabolized by the liver. Unchanged metabolites are excreted by the kidneys. Half-life is typically 1.5-2 h. Lidocaine crosses blood-brain and placental barriers by passive diffusion. Indicated for regional and local anesthesia.
Bupivacaine Hydrochloride (Sensorcaine, Marcaine)
Amide anesthetic that blocks conduction of nerve impulses by inhibiting ionic fluxes. Absorbed completely with parenteral administration and metabolized by the liver. Unchanged metabolites are excreted by the kidneys. Half-life is typically 3-4 h and peak levels are achieved in 30-40 min. Bupivacaine crosses blood-brain and placental barriers by passive diffusion. Indicated for regional and local anesthesia.
-
Nerve irritation in the herniated disk occurs at the root (sciatic radiculitis). In piriformis syndrome, the irritation extends to the full thickness of the nerve (sciatic neuritis).
