Sciatica: what is it and what causes it?

 

Everyone seems to know someone who has sciatica. It appears to be a widespread condition that causes its sufferers considerable discomfort and impacts upon their lives. Yet what exactly is sciatica and is it really that common? More importantly, how is sciatica best treated?

 

Sciatica is a pain that radiates down the leg from the buttock, following along the line of the sciatic nerve, the largest nerve in the body (Ropper & Zafonte, 2015). It is widely ill-defined and is seen as either a clinical diagnosis or a term that refers to a set of symptoms from variable causes rather than a specific diagnosis (Tulder & Koes, 2010; Jensen et al. 2019). It results from both inflammation and compression of the sciatic nerve, generally related to a disc herniation (DH) in the lower back (lumbar) region (Valet et al 2010; Ropper & Zafonte, 2015). Approximately 85% of sciatica occurrences are associated with a disc disorder (Ropper & Zafonte, 2015), however as stated, it is more commonly a term used to describe any pain that arises from the lower back and radiates down the leg without discrimination as to the cause of said pain. Spinal causes other than DH can include spondylolisthesis, tumours or fractures. There are numerous other causes of sciatica that are not specifically related to the spine, including sacroiliac joint dysfunction, piriformis syndrome, injury to the gluteal or hamstring muscles, cyclical endometriosis, birth-related compression trauma, and complications after hip fracture/dislocation (Ropper & Zafonte, 2015). The disc herniation that is the predominant cause of sciatica most commonly results from age-related degeneration (Jensen et al., 2019). As such, sciatica is more often seen in patients in their 40s and 50s (Ropper & Zafonte, 2015).

It is not only this variability in potential causes of the pain but also the variability in symptoms that make sciatica a tricky diagnosis. Pain can occur suddenly or gradually with the commencement of physical activity and depending on where the compression in the lumbar/sacral area is, can occur either unilaterally (most commonly) or bilaterally, and either more towards the front, side or back of the leg. Most commonly, pain presents at the back of the leg and down past the knee (Jensen et al., 2019). Owing to the variability in presentation, it can often be difficult to determine the cause and prescribe the appropriate treatment.

Further complicating the matter is that more often the pain experienced by the patient is referred pain from the lower back rather than as a result of a true nerve compression associated with a DH (Valet et al. 2010). This can be where the term “sciatica” is incorrectly applied and overused. Low back pain commonly occurs with sciatica but not necessarily, as do other neurological deficits including numbness or tingling (Ropper & Zafonte, 2015; Jensen et al. 2019). Delineating this difference can be challenging and is important as treatment can vary depending on the cause of a person’s pain, i.e. if it is neurological or muscular.

Other causes of sciatica are sacroiliac joint (SIJ) dysfunction and piriformis syndrome. Some research has suggested that symptoms of sciatica can result where there is improper movement in the small joints of the SIJ when there is no other evidence of disc herniation (Fortin et al. 2003). SIJ dysfunction can significantly impact the severity of sciatica symptoms and consequently the patient’s quality of life. Piriformis syndrome (PS), where the sciatic nerve is compressed or impinged by the piriformis muscle, can also result in sciatica symptoms (Cass, 2014). It occurs more commonly in women and can be caused by overuse, trauma and prolonged sitting (Jankovich et al., 2013; Singh et al. 2016). Approximately five percent of patients experiencing sciatica are diagnosed with piriformis syndrome (Jankovich et al. 2013).

Interestingly, smoking can increase your risk of developing sciatica (Shiri & Falah-Hassani, 2016), as can obesity and manual labour including sustained vibration from jobs that involve lots of driving (Koes et al., 2007; Jensen et al., 2019). These are modifiable risk factors that once addressed and coupled with a conservative treatment approach (see treatment section below) can help a person overcome and manage their symptoms as well as avoid the need for invasive surgery.

 

 

Diagnosing sciatica

Sciatica is usually diagnosed via a positive straight leg test. The straight let test is performed with the patient lying straight out on their back on a massage table. If pain, either in the patient’s leg, buttock or back is elicited when the leg of the affected side is held straight at 60 degrees or less of elevation, then this is a positive result and likely indicates sciatica. When the patient’s foot is flexed back towards them, the pain is increased in a person with sciatica, as it is when the patient’s neck is flexed towards their body. Bending of the knee or hip results in a reduction of the pain experienced. The patient’s medical history and history of the pain is important to determine as well, e.g. does the patient have multiple modifiable risk factors, such as smoking or an occupation that increases their risk of developing sciatica?

Palpation of the piriformis muscle and imaging to rule out tumours or disk herniation can be undertaken as well (Cass, 2014), although imaging is generally only recommended if conservative management has not resulted in a reduction of symptoms within 6-8 weeks or if any neurological deficits have worsened within that timeframe. MRIs are suggested as the most appropriate and safest diagnostic tool (Jensen et al., 2019). Other tests that can be performed to determine an accurate diagnosis include reflex and sensation tests (think hitting your knee with a hammer or pin-prick tests), the results of which would likely present as reduced in a person presenting with sciatica (Jensen et al., 2019).

PS associated sciatica is an extremely difficult condition to diagnose accurately, with many different tests including pelvic and rectal examinations. Eek! But if it means finding the cause of your sciatica, then it may be worth it as PS responds quite favourably to conservative physical modalities such as massage. Coupled with lifestyle modification (e.g. reduction in time spent sitting), increased physical activity and anti-inflammatory or neuropathic pain management approaches (Jankovich et al., 2013), PS and its associated sciatica symptoms can be alleviated and managed. Not discussed here are approaches that include nerve blocks and anaesthetic or botulinum toxin injections, as such approaches are rather invasive and offer somewhat mixed results as to their efficacy (Jankovich et al. 2013).

 

Treatment

Sciatica has a good prognosis following an active, conservative multi-disciplinary treatment approach, including exercise, manual therapy and pain management of about 6-8 weeks. It must be noted that where sciatica symptoms continue beyond this timeframe, further investigative and treatment options may be required, including imaging and/or surgery (Jensen et al., 2019). For those experiencing an acute onset of sciatica symptoms it is important to find a therapist who understands that the most effective treatment approach is multidisciplinary and not simply proclaim that they can fix the problem single-handedly. Fear of pain and worry that it will never get better are significant barriers to a patient’s recovery. For pain management and or psychological distress, referral to the patient’s GP is appropriate, as increased pain, disability and poor quality of life are some of the primary consequences of sciatica (Jensen et. al, 2019). When a patient presents to a massage therapist with a confirmed or suspected diagnosis of sciatica, reassurance that symptoms will most likely reduce over time is paramount (given that serious causes such as malignancies and fractures have been ruled out), as is the promotion of movement (avoiding bed rest). This can assist in ensuring that the impact on the patient’s quality of life is minimised. Importantly, the therapist needs to be knowledgeable in order to educate the patient as to what red flags to look out for, e.g. worsening pain or increased numbness and tingling (Jensen et al., 2019). It may be of interest to note that guidelines for the optimal treatment approach for sciatica do not recommend acupuncture (Jenen et al., 2019).

 

Evidence suggests that massage therapy can be effective in the treatment of sciatica and the lower back pain often associated with it (Cherkin et al., 2011; Kumar et al. 2013). Interestingly, a study comparing 10 weeks of relaxation massage and structural massage treatments (myofascial and various soft tissue techniques) found no difference in the results between the two approaches; both achieved marked improvement in pain reduction, improved function and decreased symptoms (Cherkin et al., 2011). The follow-up at 52 weeks post-treatment found that the benefits of massage where still present in the forms of overall improvement and satisfaction as compared to patients who did not receive massage (Cherkin et al. 2011). What is fascinating about this study is that the type of massage seems largely irrelevant, i.e. different massage techniques are able to achieve the same end goal through different means, e.g. structural/soft tissue massage may be more localised in its effect, whereas relaxation massage may work on the entire central nervous system to bring about the same change (Cherkin et al., 2011). This is important as many patients, especially those in extreme discomfort, may find localised, firmer massage techniques rather daunting. And of course, other patients may prefer deeper, remedial techniques. The important take-home message is that regardless of the type of massage, the benefits are many and can be long-lasting. Offering a whole-body relaxation massage, although not specifically targeting the symptomatic area, could be an alternative to achieve similar results to other massage techniques and relieve a person’s pain. This leads on to our next blog which will be looking at the benefits of touch, not only to our physical well-being but to our mental health, and how underrated and often ignored the importance of touch is.