'Sciatica' is a term used frequently by lay people and medical professionals alike. It refers to the presence of pain, tingling or numbness in the back of the thigh and calf. Sciatica occurs when there is irritation or compression of the sciatic nerve (hence the name). This may be directly in the buttock or thigh region where this nerve lies, or through irritation or compression of the spinal nerve roots that merge to form the sciatic nerve (L4-S3)
When any nerve is irritated by direct mechanical pressure, friction or inflammation, it can lead to referred pain and altered sensation in the areas of skin that the nerve supplies. Sustained mechanical pressure on a nerve cuts off blood supply and causes pain and numbness. Irritation of a nerve by inflammation or friction leads to pain and tingling sensations. In the case of the sciatic nerve, these referred symptoms are felt in the buttock and the back of the thigh, or in the calf where the sciatic nerve splits into the fibular and tibial nerves.
Now, the nerves in our body glide and move around as the rest of our body moves. This movement of nerves is referred to as 'neuro-dynamics'. Normally this movement is free and unlimited, and nerves slide and glide inside a protective sheath without being pulled taught or placed under tension. In the case of the sciatic nerve, this nerve normally slides up and down in our leg freely, and the nerve roots that supply it move in and out of the spine freely.
When there is a pathology that makes the sicatic nerve sensitive, its neurodynamics can be compromised. When a nerve is sensitive, the surrounding muscles will generate tension to try to keep the nerve still. With normal movement, gliding of the nerve is now restricted and it may actually become tethered and placed on tension. This can cause even worse referred pain, tingling or numbness. For the sciatic nerve, this often presents as tension in the buttock, hamstring and calf muscles. Similarly, if there is a lower back pathology or buttock muscle problem ( such as piriformis muscle tightness) leading to a nerve being pinched, the sciatic nerve may be tethered at some point along its length.
In order to treat sciatica effectively, physiotherapy and self management should aim to restore normal movement and gliding of the sciatic nerve and the spinal nerves that contribute to its formation. This can be done through specific nerve gliding exercises (sometimes called nerve flossing). Most importantly, these exercises do not stretch the sciatic nerve or pull it tight, rather they slide it back and forth. This has the effect of encouraging normal neuro-dynamics, and may reduce some protective muscle tone that is restricting movement of the nerve. As part of a multi-modal program, the incorporation of nerve gliding exercises helps to improve pain free movement and reduce referred pain.
The videos below show some different exercises aimed at restoring normal gliding of the sciatic nerve and the spinal nerve roots that contribute to its formation. There are several variations, however these base exercises are usually effective.
In the first video, the patient is laying flat on their back. Here they combine movements of their ankle and neck in order to produce movement in spinal cord tissue and the sciatic nerve. As they flex their neck they point their toes, and as they pull their ankle upwards they extend their neck (so the neural tissue is glided rather than pulled taught at both ends). This movement tends to produce gliding of the spinal nerve roots and spinal cord.
The next video shows a progression on the same exercise with the leg elevated. This generates a higher baseline of tension in the neural tissue, resulting in greater movement during gliding
As a final progression, this exercise can also be performed in a slump position sitting in a chair. Here the affected leg is held forward in full extension, and the patient flexes forward to a point of comfortable tension. Once again, they flex their neck as they point their toes, and extend their neck as they bend their ankle upwards.
The final video shows another progression that aims to bias movement of the sciatic nerve as it passes through the buttock and the back of thigh. As for the video above, the patient sits in a chair slumped forward. Both limbs are flexed. As they straighten the knee on their affected leg, they extend their neck upwards. As they tuck their knee back in they flex their neck. Holding their ankle pointed up helps to add slightly more movement to the neural tissue.
Each of these exercises can be helpful and effective, and the chosen exercise will depend on the severity of your symptoms. Make sure you approach nerve gliding exercises with caution, starting with only short applications of 30 seconds at a time, focusing on smooth execution. Monitor your symptoms and progress slowly to ensure you are not causing further irritation. Nerve gliding exercises should be reviewed by your physiotherapist and included as part of a more comprehensive program for managing sciatica.
Talk to your physio about your sciatica and try adding nerve gliding exercises to get a leg up on your referred pain!
The Gap Physio