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2006 Young Investigator Award Winner: Lumbosacral Nerve Root Displacement and Strain: Part 2. A Comparison of 2 Straight Leg Raise Conditions in Unembalmed Cadavers

Gilbert, Kerry K., PT, ScD*; Brismée, Jean-Michel, PT, ScD*; Collins, Dwayne L., RN, BSN; James, C Roger, PhD*; Shah, Rinoo V., MD; Sawyer, Steven F., PT, PhD*; Sizer, Phillip S. Jr, PT, PhD*

doi: 10.1097/BRS.0b013e318067dd72
Clinical Case Series
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Study Design. An inferential cadaveric study.

Objectives. To compare the displacement and strain of the lumbosacral nerve roots during different conditions of straight leg raise (SLR) with intact foraminal ligaments.

Summary of Background Data. Clinicians use sensitizing movements such as dorsiflexion during neurodynamic testing, assuming that these prepositions influence the displacement or strain to the lumbosacral nerve roots. Little is known about the effect of these prepositions on neurodynamic behavior.

Methods. Lower limbs and associated nerve roots of 5 unembalmed cadavers (n = 10) were used to evaluate the displacement and strain of the L4, L5, and S1 roots during 2 different SLR conditions. Fluoroscopic images of intraneural metal markers were digitized to evaluate displacement and strain during SLR with no preposition (SLR NPP) of the ankle and SLR with dorsiflexion preposition (SLR DF) of the ankle, respectively.

Results. SLR NPP produced larger distal displacement at L5 and S1, (P < 0.001) when compared with SLR DF. Displacement comparisons at L4 were nonsignificant (P = 0.051). While nonsignificant, medium to large effect sizes (0.60–0.96) suggest that SLR DF may produce more strain than the SLR NPP condition.

Conclusions. Prepositions of the SLR test alter the displacement and possibly the strain of the lumbosacral nerve roots in the lateral recess.

Prepositioned ankle conditions (dorsiflexion) during straight leg raise (SLR) alter the displacement and possibly the strain of lumbosacral roots. Various patterns of SLR testing should be considered to fully evaluate lumbosacral neural mobility and tension.

From the *Center for Rehabilitation Research and Department of Rehabilitation Sciences, Texas Tech University Health Sciences Center, Lubbock, TX; †Pain Management Clinic, Lubbock, TX; and ‡Guthrie Clinic, Section of Interventional Pain Medicine, Department of Anesthesiology, Sayre, PA.

Acknowledgment date: March 13, 2006. First revision date: July 19, 2006. Second revision date: September 11, 2006. Acceptance date: September 12, 2006.

Supported by the Texas Tech University Health Sciences Center, School of Allied Health Sciences.

The manuscript submitted does not contain information about medical device(s)/drug(s).

Institutional funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.

Address correspondence and reprint requests to Kerry K. Gilbert, PT, ScD, Master of Physical Therapy Program, Department of Rehabilitation Sciences, School of Allied Health Sciences, Texas Tech University Health Sciences Center, 3601 4th Street, Rm 2B180, Lubbock, TX 79430; E-mail: kerry.gilbert@ttuhsc.edu

© 2007 Lippincott Williams & Wilkins, Inc.