Intrathecal movement and tension of the lumbosacral roots induced by straight-leg raising.
OBJECTIVE
To obtain quantitative biomechanical data on the effects of different angles of straight-leg raising on intrathecal movements and tensions in the lumbosacral nerve roots in human cadavers.


METHODS
Eight embalmed human cadavers with no gross spinal pathology and no limitations in hip motion were used. We performed reverse straight-leg raising by hanging the left leg down from the table with the knee extended while measuring the movement and tension of nerve roots L2, L3, L4, L5, and S1 in 10-degree intervals for straight-leg raising from 0 to 70 degrees.


RESULTS
The mean intrathecal movements at 70 degrees were 0.55 mm, 0.54 mm, 0.96 mm, 1.54 mm, and 2.31 mm for roots L2, L3, L4, L5, and S1, respectively. The movements were statistically significant at >50 degrees for root L5 and at >40 degrees for root S1 (P < 0.05). The tension in the nerve roots with increasing angle of straight-leg raising increased from roots L2 to S1. The mean tensions at 70 degrees of straight-leg raising were 141.25 g, 168.75 g, 228.75 g, 280.00 g, and 493.75 g for roots L2, L3, L4, L5, and S1, respectively. The difference in tension was significant at >70 degrees for roots L2, L3, and L4 roots, at >40 degrees for root L5 root, and at >10 degrees for root S1 (P < 0.05).


CONCLUSIONS
The intrathecal movement and tension of the lumbosacral roots induced by straight-leg raising were <2.5 mm and <500 g, respectively. The movement and tension induced by straight-leg raising tended to be greater in more distal segmental roots.
Ko
Hyun-Yoon
HY
Department of Rehabilitation Medicine, Pusan National University Hospital, Pusan National University College of Medicine, Pusan, Korea.
Park
Byung Kyu
BK
Park
Jae Heung
JH
Shin
Yong Bum
YB
Shon
Hyun Joo
HJ
Lee
Hyun Choong
HC
D001696:Biomechanical Phenomena; D002102:Cadaver; D005260:Female; D006801:Humans; D007866:Leg / Q000502:physiology*; D008160:Lumbosacral Plexus / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology*; D013126:Spinal Nerve Roots / Q000503:physiopathology*