Diagnostic Value of Assessment Tools for Sciatica in Clinical Practice: A Systematic Review and Narrative Synthesis

Abstract

BACKGROUND: Sciatica is one of the most common reasons for seeking healthcare for musculoskeletal pain and can be a challenge to healthcare providers to diagnose and treat. In view of the variability of sciatica symptoms, a great range of patient reported outcome measures (PROMs) and performance-based measures (PBOs) have been developed for its assessment and management, with however, often poor or controversial results in their reliability and discriminative ability.  Accurate diagnosis of sciatica is crucial to ensure appropriate intervention is given. However, to date there is no gold standard to diagnose sciatica. There has been no systematic review conducted to compare the diagnostic validity of assessment tools of sciatica.

OBJECTIVE: To evaluate the diagnostic value of tools (PROMs and PBOs) used to assess patients presenting with sciatica.

METHODS: This review informed and reported in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis-Protocols. PubMed, Science Direct, Cochrane Library, CINAHL, MEDLINE, EMBASE, key journals and grey literature searched rigorously to find diagnostic accuracy studies investigating patient with sciatica. Two independent reviewers conducted the search, extracted the data and assessed risk of bias for included studies using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. The overall quality of included studies evaluated using Grading of Recommendations, Assessment, Development and Evaluation guidelines. 

RESULTS: From 8347 studies, 11 studies were included. Nine studies out of the 11 were at risk of bias. Very low level evidence supports the use of dermatomal patterns and low level evidence supports the use of 7 tools (neurological examination, Βragard test, S-LANSS, ID Pain, PDQ, S-DN4, SQST) for diagnosing sciatica. Moderate level evidence supports a cluster of eight signs (age, duration of disease, paroxysmal pain, pain worse in leg than back, typical dermatomal distribution, worse on coughing/sneezing/straining, finger to floor distance and paresis), twenty items of patient history, self-reported items (pain below knee,  which pain worst, numbness pins and needles), question «worsening of pain during sneezing coughing and straining» and Slump test for diagnosing sciatica. Also, moderate level evidence supports the use of the StEP tool for diagnosing lumbar radicular pain, demonstrating high sensitivity (92%) and specificity (97%) values. SLR showed moderate level evidence in one study and high level evidence in another study in diagnosing sciatica with sensitivity 63.46% and specificity 45.88%.

CONCLUSIONS: Overall low-moderate level evidence supports the diagnostic utility of the tools examined in this review in diagnosing sciatica.  The weak evidence base is largely due to methodological flaws and indirectness regarding applicability of the included studies. The most promising diagnostic tools include a cluster of 8 patient history/clinical examination signs, the StEP tool and the SLR test. From these results it is easily understood that history taking has a major role as assessment tool of sciatica in clinical practice. Low risk of bias and high level of evidence diagnostic utility studies are needed, in order for stronger recommendations to be made