Modified straight leg raising test: A hypothetical clinical adjunct to distinguish two types of lumbar disc herniation preoperatively

Liu, Chao; Cai, Hong-Xin; Fan, Shun-Wu; Liu, Yun-Jian

doi:10.1016/j.mehy.2009.01.045

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Volume 73, Issue 1 , Pages 52-55, July 2009

Modified straight leg raising test: A hypothetical clinical adjunct to distinguish two types of lumbar disc herniation preoperatively☆

Chao Liu
- Department of Orthopaedics, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, China
- Sir Run Run Shaw Institute of Clinical Medicine of Zhejiang University, #3 East Qingchun Road, Hangzhou 310016, China
Hong-Xin Cai
- Department of Orthopaedics, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, China
- Sir Run Run Shaw Institute of Clinical Medicine of Zhejiang University, #3 East Qingchun Road, Hangzhou 310016, China
Shun-Wu Fan
- Department of Orthopaedics, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, China
- Sir Run Run Shaw Institute of Clinical Medicine of Zhejiang University, #3 East Qingchun Road, Hangzhou 310016, China
- Corresponding author. Address: Department of Orthopaedics, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, #3 East Qingchun Road, Hangzhou 310016, China. Tel./fax: +86 057186090073.
Yun-Jian Liu
- Department of Orthopaedics, Lishui Central Hospital, Affiliated with Wenzhou Medical College, #2 Dengta Street, Lishui 323000, China

Received 8 January 2009; accepted 12 January 2009. published online 12 March 2009.

Summary

There are two anatomically different types of lumbar disc herniation, contained and noncontained. The status of disc herniation not only has a place of in planning therapeutic procedure, but also appears prognostically important. However, it is difficult to distinguish these two types completely without surgery, even by imaging studies. As a hypothetical clinical adjunct, a modified straight leg raising test is described. This novel diagnostic aid is based on the pathogenesis of sciatica, and enlightened by the mechanisms of both traditional straight leg raising test and traction. We surmise that the mechanical compression caused by herniated disc is predominant in contained type; whereas the chemical inflammatory effect is more pronounced in the pathogenesis of sciatica in noncontained type. Thus, it is hypothesized that in patients with contained type, the symptoms of sciatica, and the angles of straight leg raising test would be different before and after traction. On the other hand, in patients with noncontained type, these clinical appearances could not improve significantly. According to the different symptoms, two types of disc herniation are expected to be distinguished by the straight leg raising test preoperatively. Combined with imaging studies, this hypothetical clinical adjunct is hoped to ameliorate the accuracy of diagnosis.