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Strain and excursion in the rat sciatic nerve during a modified straight leg raise are altered after traumatic nerve injury
Author(s) -
Boyd Benjamin S.,
Puttlitz Christian,
Gan Jerylin,
Topp Kimberly S.
Publication year - 2005
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1016/j.orthres.2004.11.008
Subject(s) - sciatic nerve , strain (injury) , medicine , anatomy , sciatic nerve injury , nerve injury , ankle , nerve conduction velocity , biomechanics , anesthesia
Purpose: This study investigated the biomechanics of the sciatic nerve with hind limb positioning in live and euthanized Sprague‐Dawley rats after traumatic nerve injury. Methods: With radiographic analysis, sciatic nerve excursion and strain were measured in situ during a modified straight leg raise, which included sequential hip flexion and ankle dorsiflexion. Comparisons were made between nerves in uninjured, sham‐injured and mild crush‐injured rats at the 7‐day and 21‐day recovery times. Results: Significant strain and proximal excursion of the sciatic nerve were observed in all groups during hip flexion, and additional increased strain was noted during dorsiflexion. Seven days after nerve injury, strain increased significantly during hip flexion (17.64 ± 14.12%; p = 0.0091) and dorsiflexion (22.56 ± 15.47%; p = 0.0082) compared to the sham‐injured controls. At 21 days after injury, the strains were similar between the injured and sham‐injured groups. Conclusions: Nerve bed elongation during straight leg raise causes sciatic nerve strain and excursion towards the moving joint with the greatest movement nearest the moving joint. In the first week after injury, the maximal strain exceeded the level previously shown to impair nerve conduction and circulation. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.