Bone screws and particular applications to sacroiliac joint fusion

Abstract

Procedures for the fusion of the sacroiliac joint advantageously make use of an implant selected to distract the joint upon insertion and to maintain or increase tension upon insertion. The implant can have a varying structure along its length. In some method described herein for fusing the sacroiliac joint using an implant, an implant is screwed into the sacroiliac joint between the sacrum bone and the iliac bone. The implant comprises a shaft, a tool engagement flange at top end of the shaft, a pointed tip comprising no more than about 20 percent of the length of the screw, and threads spiraling around the shaft. For screws of particular interest, the volume displacement perpendicular to the shaft increases at least about 5 percent from a point adjacent the tip to a point near the top of the shaft. Some of the desirable screw designs can be used in other orthopedic application, especially situations involving varying bone hardness. Useful filler material can be formed from a blend of bone powder and bioactive agents.

Description

FIELD OF THE INVENTION[0001]The invention relates to methods for fusing the sacroiliac joint using anchors that distract the joint and immobilize the joint in its distracted position. The invention further relates to bone screw designs that are versatile with respect to firm anchoring in softer or harder bone structures through increasing gripping of the structure as the screw is advanced.BACKGROUND OF THE INVENTION[0002]Lower back pain is a common ailment among the population and results in pain and suffering as well as loss of work time. Thus, approaches for the treatment of back pain can both relieve suffering as well as reduce employee sick time. Since back pain results in considerable employee absenteeism, effective treatments for lower back pain have both economic benefits as well as the benefit of alleviating considerable suffering.[0003]The sacroiliac joint is located at the juncture of the ilium, the upper bone of the pelvis, and the sacrum at the base of the spine. While t...

AI Technical Summary

Benefits of technology

[0005]In further aspects, the invention pertains to a method for fusing the sacroiliac joint using an implant. The method can comprise screwing an implant into the sacroiliac joint between the sacrum bone and the iliac bone in which the implant comprises a shaft, a tool engagement flange at top end of the shaft, a pointed tip comprising no more than about 20 percent of the length of the screw, and threads spiraling around the shaft. In some embodiments, the volume displacement of the threads perpendicular to the shaft increases at least about 5 percent from a point ad

Problems solved by technology

Lower back pain is a common ailment among the population and results in pain and suffering as well as loss of w

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