Mechanics of dorsal-lumbar spine injury:​ a preliminary report

Nagel, Donald A.<sup>1</sup>; Perkash, Inder<sup>2</sup>; Piziali, Robert L.<sup>3</sup>; Hayes, Wilson C.<sup>3</sup>

Affiliations

¹Professor and Head, Division of Orthopedic Surgery, Stanford University Medical Center, Stanford, California

²Chief, Spinal Cord Injury Unit, Veterans Administration Hospital, Palo Alto, California

³Assistant Professor, Department of Mechanical Engineering, Stanford University, Stanford, California

Abstract

Thousands of people suffer spinal injuries each year. Many of the fracture dislocations in the dorsal-lumbar spine result in paraplegia. Recent investigations have identified the lap seat belt as instrumental in tension-type fracture dislocations in the dorsal-lumbar spine. This paper describes initial efforts to study whole body dynamics in simulated automobile accidents, and measure the strength of intervertebral joint components under tension. Results indicate that the position of the lap belt effects the injury pattern. Two spines were tested, and the strength and stiffness of the T12-L1 and L3-L4 posterior elements was 127 to 226 lbs. and 663 to 733 lbs./in. respectively.

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