Psych-atica!...Why your “Sciatica” may be fooling you!

By: Dr. Steven Scappaticci, B.Sc. (Hons.), CSCS, DC, FRCms

Sciatica is a condition that has been around since ancient times [1]. Anywhere from 2-40% of people will experience sciatica at some point in their lives, depending on how sciatica is defined [2]. How do we define sciatica? Does the pain have to be down the whole back of the leg to the foot? What is the pain goes halfway down the back of the leg? How about just into the buttock? That’s the biggest point of this blog, the fact that sciatica is given to any pain down the back of the leg. But is it possible to have posterior leg pain and not have sciatica?

Sciatica is commonly characterized by pain down the back of the leg, particularly due to irritation of the sciatic nerve. The issue with this is that there are a number of conditions that can send pain to the back of the leg. In order to understand this we must review some basic anatomy.

The sciatic nerve originates from the lumbar and sacral plexuses (network of nerves in the low back) to form the sciatic nerve proper deep within the gluteal muscles at the piriformis muscle [3]. It travels down the back of the leg and then divides further behind the knee (popliteal fossa) into two subsequent nerves (tibial nerve & common peroneal nerve) which then go on to supply the lower leg and split again [3]. Not accounting for any anatomical anomalies (such as the sciatic nerve piercing through the piriformis muscle) this is the general make up in all humans.

We can see from this brief description how far the sciatic nerve courses from the low back to the lower leg & how many structures it engages with. This leads us into the long list of potential causes for sciatic-like symptoms.

Starting within the low back, a patient can experience Lumbar Facet Syndrome/Irritation, in which the affected facet joint becomes irritated and can send pain into the lower back & buttocks. Speaking of joint referral (which is a form of sclerotogenous pain referral) the sacroiliac joint can also become irritated from a variety of sources and refer pain into the buttocks and posterior thigh as well.

Circling back to the low back, any space-occupying lesion such as a disc herniation or tumor could be a source of sciatic-like symptoms as well. Their presence will disrupt the space surrounding the nerves & cause irritation. Similarly, nerve roots in the low back can become irritated, without the presence of a space-occupying lesion, in the case of lumbar radiculopathies and generate similar pain presentation into the buttock and posterior thigh. A more prevalent condition that can cause pain down the legs in older individuals is Lumbar Stenosis. This is where the spinal canal decreases in size and contributes to neurogenic claudication (which is obviously different from vascular claudication) highlighted by pain down the back of the legs.

Moving away from the low back & osseous pelvic structures, we find ourselves deep within the pelvic musculature at the piriformis muscle. This muscle lies in close proximity to the sciatic nerve and in a very small percentage of cases the nerve actually passes through this muscle. A somewhat controversial, yet often talked about diagnosis is ‘Piriformis Syndrome’ where irritation of the piriformis muscle causes irritation of the nearby sciatic nerve. However, given this line of thinking, the sciatic nerve could be irritated by the close proximity of any irritated muscles, namely the hamstrings, posterior gluteus minimus, gluteus medius, gluteus maximus, and even muscles of the pelvic floor [4]. When some of these muscles surrounding the hip are involved, hip issue/pain can be ignored if the practitioner solely focuses at the sciatic like symptoms.

As an interesting aside, the term “side-atica” is a presentation where pain is generated down the outside of the leg particularly by the gluteus minimus muscle, specifically the anterior fibers, according to Travell & Simons. Although this muscle garners most of the attention, there are a number of other lateral hip muscles that can cause this presentation as well.

Some may say this discussion is splitting hairs but others may disagree and say that it is imperative to have a tissue-specific diagnosis. How frustrating would it be to treat locally at the site of pain (i.e. the posterior thigh) only when the real issue may be at a different site, the low back as an example. Specific diagnoses lead to specific treatments and specific outcomes!

Now how does one treat the issue of sciatic-like pain? Well like many answers nowadays, it depends! There are many factors to take into consideration. What does the research suggest? What are the patient’s preferences? What does clinical experience point to? Is a referral or further imaging necessary? There are many questions and sometimes it’s not a black & white answer.

What’s important is finding a practitioner who understands these things and will work with you to get you moving and feeling your best!

References:

[1] Ropper, AH; Zafonte, RD (26 March 2015). "Sciatica". The New England Journal of Medicine. 372 (13): 1240–8. doi:10.1056/NEJMra1410151. PMID 25806916.
[2] Valat, JP; Genevay, S; Marty, M; Rozenberg, S; Koes, B (April 2010). "Sciatica". Best practice & research. Clinical rheumatology. 24 (2): 241– 52. doi:10.1016/j.berh.2009.11.005. PMID 20227645.
[3] Drake, Richard L.; Vogl, Wayne; Tibbitts, Adam W.M. Mitchell; illustrations by Richard; Richardson, Paul (2005). Gray's anatomy for students. Philadelphia: Elsevier/Churchill Livingstone. ISBN 978-0-8089-2306-0.
[4] Travell & Simons Myofascial Pain & Dysfunction The Trigger Point Manual Vol 2