Oral Presentation 51st International Society for the Study of the Lumbar Spine Annual Meeting 2025

Clinical tests for lumbar instability demonstrate limited sensitivity and specificity but confer a high negative predictive value in patients with chronic low back pain (115788)

Zino Kuhn 1 , Cortez Brown 1 , Clarissa Levasseur 1 , Oluwasanmi Adenaiye 1 , Gina McKernon 1 , Sara Piva 1 , William Anderst 1
  1. University of Pittsburgh Medical Center, Pittsburgh, PA, United States

Introduction

Biomechanical data suggest that a compressive load induces a measurable sagittal plane segmental translation to predict lumbar spine stability (LSI)1,2. The current radiographic standard for diagnosing LSI relies on interpretation of intervertebral anteroposterior (AP) translation on flexion-extension (FE) radiographs3. Literature supports the notion that isolated static lumbar FE radiographs incompletely characterize the stability of the lumbar spine6,7. Clinically, the lumbar segmental mobility/pain test (LSMPT) and the prone instability test (PIT) are validated to diagnose LSI by accurately identifying patients with response to stabilization exercise programs; however, these clinical tests have not been compared to radiographic instability4,5. The purpose of this study was to quantify the sensitivity and specificity of the LSMPT and the PIT for identifying lumbar spine AP translation in response to compressive load.

Methods

Participants were enrolled from a larger study (1000 individuals) that aimed to characterize biological, biomechanical, and behavioral characteristics of individuals with cLBP8. The LSMPT and PIT were administered by a licensed physical therapist. Participants underwent computed tomography imaging and were imaged while standing within a biplane radiography system. Lumbar intervertebral translation and rotation that occurred from supine in the CT scan to upright in the biplane radiography system was measured with sub-millimeter and sub-degree accuracy using a validated measurement system8. Intervertebral translation was measured as the distance between landmarks placed on the superior posterior and inferior posterior endplates of each 3D bone model. The same landmark locations were used for the supine and upright measurements (Figure 1). The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the LSMPT and PIT were calculated using the radiographic measurements of AP translation from supine to upright as the reference standard, with >3mm as the threshold for instability9,10.

Results

250 individuals (135 females; age: 56.3±16.0 years, body mass index of 27.5±4.0 kg/m2) completed testing. Average segmental AP translation between supine and upright positioning was -0.3±0.7 mm between L1-L2, 0.0±0.7 mm between L2-L3, 0.2±0.7 mm between L3-L4, 0.7±0.9 mm between L4-L5, and 0.4±1.1 mm between L5-S1. 23 subjects translated >3mm at any of the five segments; 18 occurred between L4-L5 or L5-S1. Sensitivity, specificity, PPV and NPV of the LSMPT and PIT are summarized in Table 1.

Discussion

Our results reveal a prevalence of LSI in any segment of 9.2% in a cohort of 250 participants cLBP. The low sensitivity and specificity of the analyzed clinical tests reveal these measures may not be sufficient to diagnose LSI in isolation11. NPV equal to or greater than 0.9 in all tests suggests that these may be useful to determine which patients should not undergo further imaging to diagnose LSI, however the low prevalence of LSI is likely driving high NPV and a limitation of the study. It is also worth noting that AP translation >3mm from supine to upright is not a proven gold-standard measure of LSI. That said, Performing these maneuvers in clinic has the potential to save a significant proportion of patients with cLBP the cost and radiation exposure of further radiographic evaluation.

6739ef98b94a0-ISSLS_Figure1.png

6739f27f6bb56-ISSLS_Table1.png

  1. Axelsson P, Karlsson BS. Standardized provocation of lumbar spine mobility: three methods compared by radiostereometric analysis. Spine (Phila Pa 1976). 2005 Apr 1;30(7):792-7. doi: 10.1097/01.brs.0000157477.91870.20. PMID: 15803083.
  2. Friberg O. Lumbar instability: a dynamic approach by traction-compression radiography. Spine (Phila Pa 1976). 1987 Mar;12(2):119-29. doi: 10.1097/00007632-198703000-00007. PMID: 2954216.
  3. Majid K, Fischgrund JS. Degenerative lumbar spondylolisthesis: trends in management. J Am Acad Orthop Surg. 2008 Apr;16(4):208-15. doi: 10.5435/00124635-200804000-00004. PMID: 18390483.
  4. Hicks GE, Fritz JM, Delitto A, Mishock J. Interrater reliability of clinical examination measures for identification of lumbar segmental instability. Arch Phys Med Rehabil 2003;84:1858-64.
  5. Fritz JM, Whitman JM, Childs JD. Lumbar spine segmental mobility assessment: an examination of validity for determining intervention strategies in patients with low back pain. Arch Phys Med Rehabil. 2005;86(9):1745-1752. doi:10.1016/j.apmr.2005.03.028.
  6. Braunstein J, Hipp JA, Browning R, Grieco TF, Reitman CA. Analysis of translation and angular motion in loaded and unloaded positions in the lumbar spine. N Am Spine Soc J. 2020 Nov 20;4:100038. doi: 10.1016/j.xnsj.2020.100038. PMID: 35141606; PMCID: PMC8819970.
  7. Dombrowski ME, Rynearson B, LeVasseur C, Adgate Z, Donaldson WF, Lee JY, Aiyangar A, Anderst WJ. ISSLS PRIZE IN BIOENGINEERING SCIENCE 2018: dynamic imaging of degenerative spondylolisthesis reveals mid-range dynamic lumbar instability not evident on static clinical radiographs. Eur Spine J. 2018 Apr;27(4):752-762. doi: 10.1007/s00586-018-5489-0. Epub 2018 Feb 22. PMID: 29470715; PMCID: PMC6032516.
  8. Vo NV, Piva SR, Patterson CG, et al. 2023. Toward the Identification of Distinct Phenotypes: Research Protocol for the Low Back Pain Biological, Biomechanical, and Behavioral (LB3P) Cohort Study and the BACPAC Mechanistic Research Center at the University of Pittsburgh. Pain Med. 24(Suppl 1): S36-S47.
  9. Hammouri, Qusai M. MD*; Haims, Andrew H. MD†; Simpson, Andrew K. BS*; Alqaqa, Ahmad MD‡; Grauer, Jonathan N. MD*. The Utility of Dynamic Flexion-Extension Radiographs in the Initial Evaluation of the Degenerative Lumbar Spine. Spine 32(21):p 2361-2364, October 1, 2007. | DOI: 10.1097/BRS.0b013e318155796e
  10. Boden SD, Wiesel SW. Lumbosacral segmental motion in normal individuals. Have we been measuring instability properly? Spine (Phila Pa 1976). 1990 Jun;15(6):571-6. doi: 10.1097/00007632-199006000-00026. Erratum in: Spine 1991 Jul;16(7):855. PMID: 2402698.
  11. Plante, E., & Vance, R. (1994). Selection of preschool language tests: A data-based approach. Language, Speech, and Hearing Services in Schools, 25(1), 15–24. https://doi.org/10.1044/0161-1461.2501.15