Extending the straight leg raise test for improved clinical evaluation of sciatica — The International Society for the Study of the Lumbar Spine
  1. Schedule
  2. SESSION #11 - NON SURGERY
  3. Extending the straight leg raise test for improved clinical evaluation of sciatica

Extending the straight leg raise test for improved clinical evaluation of sciatica (#64)

Janne Pesonen 1 2 , Michael Shacklock 1 3 , Juha-Sampo Suomalainen 4 , Lauri Karttunen 1 2 , Jussi Mäki 1 2 , Olavi Ariaksinen 1 2 , Marinko Rade 1 5 6
  1. Department of Rehabilitation, Kuopio University Hospital, Kuopio, Finland
  2. Department of Surgery, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Itä-Suomen lääni, Finland
  3. Neurodynamic Solutions, Adelaide, South Australia, Australia
  4. Department of Radiology, Kuopio University Hospital, Kuopio, Itä-Suomen lääni, Finland
  5. Josip Juraj Strossmayer University of Osijek, Faculty of Medicine, Orthopaedic and Rehabilitation Hospital “Prim. dr. Martin Horvat”, Rovinj, Croatia
  6. Department of Natural and Health Studies, Juraj Dobrila University of Pula, Pula, Croatia

INTRODUCTION: The straight leg raise test (SLR) is one of the most utilized and studied physical tests in patients with low back pain for the detection of lumbar disc herniation (LDH), showing high sensitivity and heterogeneous or low specificity. Based on in-depth knowledge from previous studies on neural movement during the SLR on subjects with or without pathology, we were able to add location-specific structural differentiation movements to the traditional SLR for it to better discern neural symptoms from musculoskeletal. Hence, the test was named the extended straight leg raise test (ESLR). The differentiating movements were ankle dorsiflexion for proximally reproduced symptoms (buttock/hamstring), and hip internal rotation for distally (below the knee) emerged responses. The hip flexion angle was not limited to any specific angle. Having previously found that the ESLR is both repeatable and reliable to detect sciatic patients from low back pain patients, we wanted to assess how the ESLR predicted pathology seen on the MRI.

METHODS: 40 subjects comprised the study population, 20 in sciatic group and 20 in control group. The study controller allocated the patients to these groups. The ESLR was performed ‘blinded’ to the subjects by two independent examiners and judged positive/negative. After the ESLR testing, each subject’s lumbar MRI was evaluated. The MRIs were analyzed independently by 2 senior radiologists and a spine specialist. Cohen’s Kappa was calculated for the agreement of the test result. To obtain the odds ratio (OR) for positive ESLR result for LDH or nerve root compression (NC), a binary logistic regression analysis with subjects’ age, gender, height and weight was performed. ESLR’s validity was assessed by combination of interrater agreement (Cohen’s Kappa) of independent examiners and percentage prevalence of both LDH and NC.

RESULTS: The extended straight leg raise test (ESLR) showed almost perfect interrater reliability between examiners and ability to detect sciatic patients: Cohen’s Kappa was 0.85 between blinded examiners, and 0.90 and 0.95 when compared to group allocation, respectively. In the MRI scans, 85% of sciatic (ESLR+) patients had LDH and 75% NC in the MRI. Not surprisingly, MRI showed a very high incidence of ‘false-positive’/pathologic/asymptomatic findings with the ESLR negative group. A positive result in the ESLR was found to be highly predictive for both LDH and NC: the OR was 8.0 (p = 0.028) and 5.6 (p = 0.041), respectively.

DISCUSSION: The ESLR showed high repeatability, reliability and validity in detecting neural symptoms and pathology seen in the MRI when judged positive. It is noteworthy that these results were obtained when the ESLR was performed to the patients blindly, and its performance should even improve in detecting patients experiencing sciatic symptoms when its combined to the normal patient history and clinical examination.

#ISSLS2022