The role of Botulinum toxin A in the management of piriformis syndrome

The role of Botulinum toxin A in the management of piriformis syndrome


Botulinum toxin is basically a neurontin protein produced by the bacterium clostridium botulinum and is one of the most poisonous naturally occurring substances in the world.

Produced in accordance with the regulations of the FDA, it is generally sold under the brand names Botox and Dysport.

Meanwhile, the piriformis syndrome is defined as a neuromuscular disorder that occurs when the piriformis muscle compresses or irritates the sciatic nerve, the largest nerve in the body.

The piriformis muscle is a narrow muscle found in the buttocks. Piriformis Syndrome generally occurs when the piriformis muscle becomes tight or spasms and places pressure on the sciatic nerve running beneath it.

Botulinum toxin A and Piriformis Syndrome

The injections of botulinum toxin A administered into the piriformis have recently emerged to be significant for of treatment for piriformis syndrome.

Experts indicate that the botulinum toxins inactivate the myoneural junction, the connection between nerves and muscles, in the local area of the injection. As the piriformis syndrome is basically due to the powerful tightening of the piriformis muscle, this inactivation is likely to loosen the grip of the muscle sufficiently to relieve the pain that has been caused by the muscle tightness.

One of the most significant features of the botulinum toxin A which makes it a preferred choice for pain management is that the effects of the neurotoxin are believed to act only upon the motor nerve endings, sparing the sensory nerve fibers from any side effects. With the mechanism of action being highly specific, the adverse and systemic effects are generally uncommon.

Research and Analysis

A series of research reports and studies have been undertaken to analyze the role of the botulinum toxin A in treating piriformis syndrome.

Various sets of studies conducted across patient groups have revealed that the botulinum toxin can effectively relieve the painful condition associated with piriformis syndrome, especially in cases where other therapies have failed to produce the desired effect.

A review of 50 patients suffering from the piriformis syndrome was taken up for the purpose. Each of these patients was on an existing prescription of various analgesics including NSAIDs, tramadol, gabapentin or long-acting opioids. Standard dosage of 100 U of botulinum toxin-A mixed in 5 cc of preservative-free normal (0.9 N) saline were used for the purpose.

The study revealed that with the administration of botulinum toxin A injections into the piriformis muscle, atleast a 45% reduction in pain was experienced along with a considerable increase in disability scores.

Another study was also conducted to asses the efficacy of intramuscular botulinum toxin A in decreasing chronic pain associated with piriformis syndrome. The patients involved in this study included nine women with chronic buttock, hip and lower limb pain, without any evidence of lumbar disk herniation or nerve root impingement on imaging studies. The analgesic impact of botulinum toxin A injection of 100 U was compared against a similar injection of the vehicle (saline) alone.

The study concluded that the intramuscular piriformis injection with 100 units of botulinum toxin A is capable of reducing pain to a greater extent than similar injections with the vehicle alone.

Piriformis Syndrome Information Resources and Case Reports Link

Links for Botox and Pain