Sciatica: Epidemiology and Prevalence
LBP is a commonly occurring condition that affects approximately 70% of individuals at some point, with varying levels of symptom severity. One of the most common variations of LBP is leg pain related to the lower back, also known as sciatica.
Sciatica is referred to by different terms in the literature, including lumbosacral radicular syndrome, radiculopathy, nerve root pain, and nerve root entrapment or irritation.
There is a disagreement among clinicians and researchers regarding the use of the term sciatica because it does not accurately reflect the nature of leg pain caused by involvement of the lumbosacral nerve roots.
It is strongly recommended that the term sciatica be replaced with more accurate and explanatory terms such as nerve root pain or radiculopathy to better describe the condition.
However, for the sake of convenience in this review, the term sciatica will be employed, even though it is acknowledged that nerve root pain or radiculopathy more accurately describe the nature of the issue.
In clinical practice, sciatica, a form of low back pain (LBP), is easily recognizable in most cases. It is typically characterized by pain radiating below the knee into the foot and toes, following the distribution of the affected nerve root, commonly L5 or S1.
Additional symptoms may include numbness, pins and needles sensation, muscle weakness, and reflex changes. Sciatica is considered a symptom rather than a specific diagnosis, with lumbar disc herniation and lumbar canal or foraminal stenosis being common underlying causes.
Rarely, tumors, cysts, or other extraspinal factors can also lead to sciatica. Inflammation resulting from irritation or compression of the affected nerve root by surrounding tissues is believed to be the primary cause of symptoms.
Literature findings have questioned the commonly held belief that the majority of individuals with sciatica recover well and naturally resolve their symptoms. Instead, these findings indicate that patients with sciatica often experience a more enduring and intense form of pain when compared to individuals with low back pain (LBP).
Additionally, they tend to have a less favorable outcome, necessitate greater utilization of healthcare resources, face prolonged disability, and endure longer periods of work absence.
Fewer studies have focused specifically on sciatica in comparison to research on general low back pain. The discrepancies in reported prevalence rates of sciatica can be attributed to varying definitions of the condition and challenges in distinguishing it from other types of leg pain.
It is vital to accurately differentiate between sciatica and other forms of referred leg pain in order to comprehend its nature and prevalence effectively.
Factors such as different data collection methods, varying definitions of sciatica, the populations studied, and the time frames in which prevalence figures are reported contribute to the wide range of reported sciatica prevalence.
The reported prevalence of sciatic symptoms in the literature shows significant variability, with values ranging from 1.6% to 43%. This wide range of reported sciatica prevalence can be attributed to these factors collectively.
The prevalence of sciatic symptoms varies depending on the strictness of the definition used. Stricter definitions result in lower prevalence rates, while studies with less stringent definitions report higher rates.
Factors such as pain distribution, duration, and medical diagnosis or treatment influence prevalence figures. The possibility of underestimation exists when relying on physician diagnosis or treatment, as not all individuals with sciatic symptoms seek medical attention.
The annual prevalence rates of sciatica in the general population, characterized as low back pain accompanied by leg pain below the knee, ranged from 9.9% to 25%. Clinical examinations typically show lower rates.
One study found a point prevalence of 4.8% based on clinical examination, while another study estimated a six-month prevalence of 1.2%. However, it’s important to consider that clinical examinations reflect symptoms on the day of assessment and may underestimate the impact of fluctuating conditions such as sciatica.
The variation in reported prevalence rates of sciatica in the literature is influenced by the specific populations being studied. Working populations, particularly those involved in manual and physically demanding occupations, tend to exhibit higher rates of sciatica prevalence.
However, comparing these rates directly is challenging due to differences in study designs. Furthermore, the age composition of the study populations can also contribute to the variability observed.
To explore the correlation between sciatica and age, it would be necessary to have age-specific data within a single study, which was not available in the studies examined.
The review findings did not support previous estimates of sciatica prevalence, which were as high as 40%. These estimates were likely based on studies involving populations with low back pain (LBP), which were not included in this specific review.
However, understanding the prevalence of sciatica among individuals experiencing LBP can be useful for healthcare services, as it is acknowledged that those with sciatic symptoms often require more healthcare resources and have a less favorable recovery compared to individuals with LBP alone. Sciatica is consistently recognized as an indicator of poorer prognosis.
While clinical examination is recognized as the preferred approach for assessing these symptoms, it may not always be practical in epidemiological research. Furthermore, the fluctuating nature of conditions like sciatica makes point prevalence estimates less reliable in determining the presence of symptoms. In such cases, self-reporting becomes necessary, even when clinical examination is available.
Using “pain below the knee” as a substitute for sciatica is a reasonable approach until a more appropriate definition is established through further research.
The correlation between self-reported leg pain related to low back pain and findings from clinical examinations is currently unknown, as is the possibility of a collection of self-reported signs and symptoms that may offer comparable estimates to clinical assessments.
Precisely describing and capturing these symptoms is of utmost importance for epidemiological and intervention research since sciatic pain is recognized as a risk factor for unfavorable outcomes in cases of low back pain.
The definition of sciatic symptoms and the inclusion of working populations with physically demanding jobs contribute to the observed differences. Improved estimates can be achieved through future epidemiological studies with accurate self-reporting methods.
Accurate and comparable epidemiological evidence of sciatica can inform healthcare resources and research efforts, considering its individual and societal costs.