Mechanical considerations for the syndesmosis screw. A cadaver study.

The purpose of this study was to examine the mechanical necessity of using a syndesmosis screw to supplement rigid internal fixation of the fibula and medial malleolus in the treatment of pronation-external rotation fractures. The legs of thirty embalmed and five fresh cadavera were dissected and mounted through the tibia to a frame so that multiple radiographs could be made with a constant relationship between the specimen and the x-ray apparatus. A standardized pronation-external rotation load was applied to the foot, and widening of the syndesmosis was studied on mortise radiographs that were made after each experimental step. On the basis of previous investigations, we developed a model for pronation-external rotation injuries that included disruption of the syndesmosis and interosseous membrane up to the level of the fibular fracture. Accordingly, multiple repaired fibular fractures could be simulated at several levels in the same specimen by incremental proximal division of the interosseous membrane. Specimens were separated into two groups. Group I consisted of thirteen specimens in which the deltoid ligament, syndesmosis, and interosseous membrane were serially sectioned in 1.5-centimeter increments. Group II (ten sections) was subjected to the same protocol, except that the deltoid ligament was kept intact until the final step. The five fresh specimens were sectioned in the same way as those in Group I. In Group I, since the simulated pronation-external rotation injury included a deltoid tear, rigid medial fixation was not possible; accordingly, there was rigid fibular fixation only.(ABSTRACT TRUNCATED AT 250 WORDS)

Lumbar spinal fusion: advantages of posterior lumbar interbody fusion.

From its inception in 1911, the topic of spinal fusion has seemingly been shrouded in controversy. In that year, Dr. Russell Hibbs performed the first human spinal fusion on a patient with spinal tuberculosis. This spawned a debate over the procedure that led to the denial of Hibbs' membership to the American Orthopedic Association. The procedure (and Hibbs' appointment to the AOA) was validated by the Association after ten years of debate. The debate over spinal fusions is manifold to this date. The literature is replete with differing opinions regarding the indications, techniques and outcomes of spinal fusions. The topic is further compounded by the fact that the specifics of a spinal fusion are often distinct to the area of the spine fused.

The pathogenesis of cervical spondylosis.

Cervical spondylosis is a generalized disease process affecting all levels of the cervical spine. Cervical spondylosis encompasses a sequence of degenerative changes in the intervertebral discs, osteophytosis of the vertebral bodies, hypertrophy of the facets and laminal arches, and ligamentous and segmental instability. The natural history of cervical spondylosis is associated with the aging process. Senescent and pathologic processes are thus morphologically indistinguishable. Clinical manifestations of cervical spondylosis may arise when morphologic sequelae are superimposed on a developmentally narrow spinal canal. The two clinical syndromes of spondylotic radiculopathy and myelopathy are distinct, yet they may overlap.