The authors are from the University of Virginia, Charlottesville, Va.
The authors have no financial or proprietary interest in the materials presented herein.
Address correspondence to Susan Saliba, PhD, ATC, PT, PO Box 400407, Charlottesville, VA 22904; e-mail: email@example.com.
Most individuals with recurrent episodes of lower back pain do not have an identifiable structural diagnosis such as a pathological disc or a facet injury.1 A treatment-based classification system is an alternative to establishing a structural diagnosis and is relevant for athletic trainers and physical therapists.2 The treatment-based classification system identifies similarities among a subset of individuals with lower back pain so that clinicians can select appropriate interventions to improve outcomes.2–5 These classification systems have been developed using the best clinical evidence. One subset of the classification system includes individuals who are thought to benefit from spine stabilization exercises.6–8
Typically, individuals with lower back pain who are thought to benefit from lumbar stabilization have one or more lumbar spinal segments that demonstrate a loss of segmental stiffness. Clinical assessment of segmental stiffness is possible using a posterior to anterior (PA) glide of the individual vertebral segment. The prone instability test first uses the PA glide to assess segmental stiffness and pain provocation with the muscles in a resting state (Figure 1) and then during an active contraction (Figure 3). The purpose of this column is to describe the procedure and interpretation of the prone instability test. Results from this test can help clinicians identify patients who might benefit from a spine stabilization program.6,9
Figure 1. While the Musculature of the Spine Is in a Relaxed State, the Clinician Applies a Posterior-To-Anterior Glide over Individual Segments of the Lumbar Spine. The Provocation of Pain at Any Segment Is Noted.
Figure 2. The Patient Actively Raises Her Legs, and the Posterior-To-Anterior Pressure Is Reapplied. If the Pain over the Segment Is Lower with the Active Contraction, the Test Is Positive. A Positive Prone Instability Test Suggests that the Patient Would Benefit from Spinal Stability Exercises.
Figure 3. Hand Placement with Corresponding Pressure Applied in a Posterior-To-Anterior Direction to the L5 Spinal Segment.
The prone instability test involves a provocative maneuver to determine whether muscular contraction can increase spine stability and thus reduce pain during a PA glide. The test starts with the patient prone (Figure 1) with the legs over the edge of the treatment table and the feet on the floor. The clinician applies a PA glide to the spinous process of each lumbar vertebral segment and locates the symptomatic segment (Figure 3). The second portion of the test requires the patient to raise his or her legs from the floor and then the clinician reapplies the PA pressure (Figure 2). If the patient’s pain during the second test decreases compared with the pain experienced during the first, then the test is considered positive. The test can be useful for the clinician to identify the need for a progressive therapeutic exercise program to increase lumbar spinal stabilization.
This test is a component of a cluster of signs and symptoms associated with segmental instability that might improve with stabilization exercises.3,5,10,11 Patients who are most likely to benefit from spine stabilization exercise will exhibit at least 3 of the following: younger than 40 years old; straight leg raise greater than 90; aberrant movement present with lumbar spine mobilizations; and positive prone instability test. The use of this cluster of tests can aid clinicians in selecting appropriate interventions for a subset of individuals with lower back pain.
- Abenhaim L, Rossignol M, Gobeille D, Bonvalot Y, Fines P, Scott S. The prognostic consequences in the making of the initial medical diagnosis of work-related back injuries. Spine. 1995;20:791–795. doi:10.1097/00007632-199504000-00010 [CrossRef]
- Delitto A, Erhard RE, Bowling RW. A treatment-based classification approach to low back syndrome: Identifying and staging patients for conservative treatment. Phys Ther. 1995;75:470–489.
- Fritz JM, Brennan GP, Clifford SN, Hunter SJ, Thackeray A. An examination of the reliability of a classification algorithm for subgrouping patients with low back pain. Spine. 2006;31:77–82. doi:10.1097/01.brs.0000193898.14803.8a [CrossRef]
- Brennan GP, Fritz JM, Hunter SJ, Thackeray A, Delitto A, Erhard RE. Identifying subgroups of patients with acute/subacute “nonspecific” low back pain: Results of a randomized clinical trial. Spine. 2006;31:623–631. doi:10.1097/01.brs.0000202807.72292.a8 [CrossRef]
- Hicks GE, Fritz JM, Delitto A, McGill SM. Preliminary development of a clinical prediction rule for determining which patients with low back pain will respond to a stabilization exercise program. Arch Phys Med Rehabil. 2005;86:1753–1762. doi:10.1016/j.apmr.2005.03.033 [CrossRef]
- 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;84:1858–1864. doi:10.1016/S0003-9993(03)00365-4 [CrossRef]
- Fritz JM, Erhard RE, Hagen BF. Segmental instability of the lumbar spine. Phys Ther. 1998;78:889–896.
- O’Sullivan PB. Lumbar segmental ‘instability: Clinical presentation and specific stabilizing exercise management. Man Ther. 2000;5(1):2–12. doi:10.1054/math.1999.0213 [CrossRef]
- 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;86:1745–1752. doi:10.1016/j.apmr.2005.03.028 [CrossRef]
- George SZ, Delitto A. Clinical examination variables discriminate among treatment-based classification groups: A study of construct validity in patients with acute low back pain. Phys Ther. 2005;85:306–314.
- Fritz JM, Cleland JA, Childs JD. Subgrouping patients with low back pain: Evolution of a classification approach to physical therapy. J Orthop Sports Phys Ther. 2007;37:290–302.