I have leg pain – does this mean I have sciatica?
Many patients will come to us and tell us they are suffering from “sciatica” because they’re experiencing pain from their low back or hip and into the legs. Some of these patients are suffering from sciatica but many other patients are not suffering from true “sciatica” but rather some other form of leg pain. Confused?? How can I have leg pain but not sciatica? Well not all referred leg pain comes from the same cause. There are in fact many causes of referred leg pain and finding the real cause is very important in shaping the treatment we deliver as well as the prognosis for the patient. The term “sciatica” is commonly used and misused by patients and practitioners and therefore purpose of this post is to help give some clarity on what is sciatica and what isn’t!
Disc herniation compressing on spinal nerve roots potentially causing radiculopathy and sciatic pain.
True sciatica refers to a condition called lumbosacral radiculopathy. Radiculopathy specifically involves the compression or irritation of a spinal nerve root by some cause and results in motor and sensory changes as well as pain in the lower limb. Radiculopathy can occur at any spinal level, however for the term sciatica to be used correctly, the radiculopathy must involve the nerve roots of L4-S2. These are the nerve roots which will ultimately become the sciatic nerve. Radiculopathy may involve radicular pain, which is pain that radiates into the lower extremity due to the compression or irritation of a nerve root. Radiculopathy can result from many different causes, the most common is of course a disc bulge or herniation. Some other causes of radiculopathy include:
- Disc herniation – most common. 90% of the time.
- Degenerative changes to the bony surrounds of the nerve roots – these are specifically termed osteophytes. This creates what we call stenosis, meaning constriction around the path of the nerve root.
- Chemical irritation of the nerve root by inflammatory processes
- Space occupying lesions – these may include tumours or abscesses
- Neurological conditions – Guillain-Barre syndrome, herpes zoster (shingles)
Someone with true sciatica/radiculopathy will present with typical symptoms of radiculopathy which include:
- Pain that is describe as sharp, aching, throbbing, electrical shock, burning, dull
- The pain is usually in a well-defined location in the leg rather than a diffuse and non-specific pain. Each nerve root has a correlating region of skin for which it supplies sensation. For someone with “sciatica” this region is from the gluteal area à back of the thigh à back of the knee à the leg and foot. Local pain in the back is also reported.
- The patient may report sensory changes such as numbness, pins and needles, tingling or burning in the above regions of the leg.
- Muscle weakness in the affected leg. The affected nerve root also supplies specific muscles in the leg.
- Decreased reflexes
The above picture demonstrates dermatomes for the lower limb. Dermatomes are the area of skin that is innervated/supplied by a specific nerve root.
The symptoms above may be exacerbated by certain factors. These factors are mostly applicable for radiculopathy caused by a disc herniation. They include; bending forward, sitting, coughing, sneezing, defecating, straining, twisting etc. The symptoms are typically relieved with lying down or walking. The presence or absence of these factors are important in determining our diagnosis. However it is important to note that note all cases are carbon copies and these factors need to be taken into consideration with other signs and symptoms. Pain on forward bending can be caused by many other low back issues for example.
So that covers true sciatica, but what about all the other causes of leg pain?? There are many causes of referred leg pain, each with different presentations. Referred pain from musculoskeletal structures is typically a different sort of pain compared to radicular pain. Referred pain is usually a dull, deep, non-specific, ache. Most of the common causes originate from musculoskeletal structures, they include:
- Muscles: certain muscles in the lumbopelvic/hip region have the potential to refer pain into the leg such as the piriformis muscle or gluteus medius muscle.
- Joints: again the joints of the lumbopelvic region can refer pain into the legs. These joints include – lumbar facet joints, sacroiliac joints (SIJ), and hip joint.
- Bursa: Bursa are fluid filled sacs found throughout the body. They help to act as cushions and lubricating structures around and between tissues where pressure and friction occurs. Inflammation of bursa in the hip can cause some locally referred pain into the thigh and buttock.
- Sciatic neuropathy: Compression of the sciatic nerve away from the nerve roots in the low back can occur also. Piriformis syndrome is another cause of leg pain. It results from the sciatic nerve compression or irritation from the piriformis muscle.
Gluteus medius trigger point referral pattern
So as you can see not all leg pain is “sciatica” and it is very important to find the true source of the pain so that the right treatment can be administered. If you’re experiencing leg pain or have any questions regarding the post feel free to contact us for more information!