Testing for Nerve Root Impingement
This is the Medscape Neurology Minute. I'm Dr. Alan Jacobs. Researchers at the New England Baptist Hospital in Boston [Massachusetts] have published a cross-sectional study with prospective recruitment to determine the accuracy of the physical examination for the diagnosis of middle lumbar and lower lumbar nerve root impingement and level-specific lumbar nerve root impingement on MRI. Likelihood ratios ≥ 5 indicated moderate-to-large changes from pre-test probability of nerve root impingement to post-test probability. The diagnosis of midlumbar impingement was achieved by the femoral stretch test, crossed femoral stretch test, medial ankle pinprick sensation, and patellar reflex testing. When combining the femoral stretch test with either the patellar reflex testing or the sit-to-stand test, the likelihood ratio was also ≥ 5. For the diagnosis of level-specific impingement, likelihood ratios ≥ 5 were observed for anterior thigh sensation at L-2, femoral stretch testing at L-3, patellar reflex testing, medial ankle sensation or crossed femoral stretch testing at L-4, and hip abductor strength at L-5. Test combinations increased the likelihood ratio for level-specific root impingement at the L-4 level only. The authors conclude that individual physical examination tests provide clinical information that substantially alters likelihood that midlumbar, low-lumbar, or level-specific impingement is present.
This article was selected from Medscape Best Evidence. I'm Dr. Alan Jacobs.
Abstract
This is the Medscape Neurology Minute. I'm Dr. Alan Jacobs. Researchers at the New England Baptist Hospital in Boston [Massachusetts] have published a cross-sectional study with prospective recruitment to determine the accuracy of the physical examination for the diagnosis of middle lumbar and lower lumbar nerve root impingement and level-specific lumbar nerve root impingement on MRI. Likelihood ratios ≥ 5 indicated moderate-to-large changes from pre-test probability of nerve root impingement to post-test probability. The diagnosis of midlumbar impingement was achieved by the femoral stretch test, crossed femoral stretch test, medial ankle pinprick sensation, and patellar reflex testing. When combining the femoral stretch test with either the patellar reflex testing or the sit-to-stand test, the likelihood ratio was also ≥ 5. For the diagnosis of level-specific impingement, likelihood ratios ≥ 5 were observed for anterior thigh sensation at L-2, femoral stretch testing at L-3, patellar reflex testing, medial ankle sensation or crossed femoral stretch testing at L-4, and hip abductor strength at L-5. Test combinations increased the likelihood ratio for level-specific root impingement at the L-4 level only. The authors conclude that individual physical examination tests provide clinical information that substantially alters likelihood that midlumbar, low-lumbar, or level-specific impingement is present.
This article was selected from Medscape Best Evidence. I'm Dr. Alan Jacobs.
Abstract
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