The strength of a posterior element claw at one versus two spinal levels.
In the Cotrel-Dubousset and Texas Scottish Rite Hospital spinal implants systems, the upper hook on the convex rod is usually clawed to prevent posterior pull out. A transverse process hook and an upwardly directed pedicle hook are usually inserted on the same lamina level. However, clawing two levels instead of one is a simpler surgical procedure. We biomechanically compared the posterior pull-out strength of a one-level versus two-level construct. The average load of failure of the double-level construct was significantly greater (p less than 0.05) as compared with the single level. Thus, the two-level construct is not only easier to insert, it is also stronger.
Roach
J W
JW
Research Department, Texas Scottish Rite Hospital, Dallas 75219.
Ashman
R B
RB
Allard
R N
RN
D000818:Animals; D002417:Cattle; D004867:Equipment Design; D016268:Internal Fixators; D013123:Spinal Fusion / Q000295:instrumentation*; D013314:Stress, Mechanical; D013904:Thoracic Vertebrae / Q000601:surgery