What Is A Sciatic Nerve Block?

The sciatic nerve is the largest nerve in the body, running from the pelvis through the hips and buttocks and down the back of each leg. The sciatic nerve transmits sensory information from the legs to the spinal cord. It also provides motor control for the lower extremities. The sciatic nerve is comprised of multiple bundles of nerves that can result in lumbar spine pain, leg and foot pain, numbness, tingling, burning, cramping, and muscle weakness if they become compressed.

Sciatic nerve pain, also known as sciatica, typically only affects one side of the body. The hallmark sign of sciatica is pain that radiates from the lower back, into the buttocks, and then down the back of the leg. Sciatica commonly occurs when a herniated disc compresses part of the nerve. However, it can also be caused by other conditions that affect the spine including bone spurs, spinal stenosis, arthritis, or nerve root compression. In rare cases, the nerve may become compressed by a tumor and pregnancy may also result in sciatic nerve pain.

The pain that is associated with sciatica varies in severity and can range from mild to severe. Most cases of sciatica resolve with conservative treatment methods including cold and hot packs, physical therapy, and over-the-counter medications. However, some patients continue to suffer from sciatic nerve pain even while receiving conservative treatment.

A sciatic nerve block is a minimally invasive procedure that can be offered to patients who suffer from severe, debilitating sciatic nerve pain or to those who continue to suffer from unrelenting pain despite attempting conservative treatment methods. A sciatic nerve block helps to block the transfer of sensory information from the lower extremities to the spinal cord and brain. Blocking the transfer of information helps to reduce or eliminate sciatic nerve pain.

How Is A Sciatic Nerve Block Performed?

Physicians have several methods that they can use to target the bundle of sciatic nerves due to its large size. These methods include the lateral popliteal approach, the midfemoral approach, the subgluteal approach, and the posterior popliteal approach. Sciatic nerve block procedures focus on injecting a corticosteroid adjacent to a peripheral nerve as opposed to injecting the medication directly into the nerve root.

Prior to the procedure, a local anesthetic is used to numb the injection site tissue. Once the area is sufficiently numb, the physician inserts a small needle into the desired area using fluoroscopic guidance. Contrast dye is then injected to ensure proper needle placement and proper medication distribution. Once proper needle placement is confirmed, the physician will inject the anesthetic medication. Corticosteroids may be added to the injection in areas where there is significant inflammation.

Sciatic nerve blocks are relatively quick to perform and the pain relief effects are experienced almost immediately after the injection. After the procedure is complete, patients are moved to a recovery area where they are monitored for adverse reactions for one to two hours. For patients who do not have a significant reduction in pain levels following the procedure, effects may be enhanced after a few repeat injection procedures.

Sciatic nerve blocks are considered a safe and effective treatment option for sciatic nerve pain; however, as with any medical procedure, there are risks associated with this treatment. The most common side effect is injection site tenderness following the procedure. Other side effects include nausea, vomiting, and headache. Rare side effects include bleeding and infection.

Conditions Related To Sciatic Nerve Blocks

Sciatic nerve blocks can be an effective treatment option for patients suffering from chronic, severe sciatic nerve pain that is non-responsive to conservative treatment methods. Sciatica is often difficult to diagnose as the symptoms often overlap with other low back injuries. Oftentimes patients are able to identify an event that occurred which may have triggered their sciatic nerve pain. These events can include a slip and fall, a motor vehicle accident, or other acute traumatic events.

However, it should be noted that acute events are not responsible for all cases of sciatic nerve pain. Research has found that there are a number of characteristics that increase an individual’s risk of suffering from sciatic nerve pain, including:

  • Increasing age
  • Obesity
  • Occupations that involve repetitive twisting, heavy lifting, or prolonged driving
  • Prolonged sitting
  • Diabetes

Before undergoing a sciatic nerve block it is recommended that patients attempt conservative home treatment options including ice, heat, specific exercises, and over-the-counter pain and anti-inflammatory medications. If these treatments fail, a sciatic nerve block may be an ideal treatment option as they have been shown to be effective for reducing sciatic nerve pain in the lower extremities. Sciatic nerve blocks may also be beneficial for patients who experience undesirable side effects from traditional pain management medications.

Conclusion

A sciatic nerve block is an effective treatment option for patients who are suffering from chronic, severe sciatic nerve pain that is non-responsive to conservative treatment methods. Sciatic nerve blocks are non-surgical and carry few risks. In addition they also provide patients with almost immediate pain relief. Sciatic nerve blocks are an ideal option to offer to patients prior to considering surgery for sciatic nerve pain relief.

References

  1. Chen L, Wang Q, Shi K, Liu F, Liu L, Ni J, Fang X, Xu X. The effects of lidocaine used in sciatic nerve on the pharmacodynamics and pharmacokinetics of ropivacaine in sciatic nerve combined with lumbar plexus blockade: a double-blind, randomized study. Basic Clin Pharmacol Toxicol. 2013;112(3):203-8.
  2. Cuvillon P, Reubrecht V, Zoric L, Lemoine L, Belin M, Ducombs O, Birenbaum A, Riou B, Langeron O. Comparison of subgluteal sciatic nerve block duration in type 2 diabetic and non-diabetic patients. Br J Anesth. 2013;110(5):823-30.
  3. Luo D, Wang X, He J. A comparison between acute pressure block of the sciatic nerve and acupressure: Methodology, analgesia, and mechanism involved. J Pain Research. 2013;6:589-593.
  4. Ponde V, Desai AP, Shah D. Comparison of success rate of ultrasound-guided sciatic and femoral nerve block and neurostimulation in children with arthrogryposis multiplex congenita: a randomized clinical trial. Paediatr Anaesth. 2013;23(1):74-8.
  5. Sala-Blanch X, de Riva N, Carrera A, López AM, Prats A, Hadzic A. Ultrasound-guided popliteal sciatic block with a single injection at the sciatic division results in faster block onset than the classical nerve stimulator technique. Anesth Analg. 2012;114(5):1121-7.
  6. Seidel R, Natge U, Schulz J. Distal sciatic nerve blocks: randomized comparison of nerve stimulation and ultrasound guided intraepineural block. Anaesthesist. 2013;62(3):183-88,190-2.
  7. Tammam TF. Ultrasound-guided infragluteal sciatic nerve block: A comparison between four different techniques. Acta Anaesthesiol Scand. 2013;57(2):243-8.