Compression bone staple, apparatus and method

Abstract

A method and apparatus for interosseous bone fixation uses a compression staple, generally U-shaped, having a pair of legs with sharp front ends and proximal ends interconnect by a bridge portion that is resilient and bowed, the staple having an initial configuration and capable of a tensioned configuration by spreading apart the legs by a certain amount causing the curvature of the bowed bridge to lessen and the legs urged towards each other with certain compressive spring force. A staple applicator supports and guides the staple and positions the tensioned staple with its pointed ends forward, adjacent an ejection port at the front of the applicator. A powered strike member is mounted for longitudinal movement and has a front end that will strike the rear of the tensioned staple with percussive force and eject it in tensioned configuration from the applicator.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to devices and techniques for securing bone segments across a fracture site, and more particularly relates to a bone stapling method and apparatus for achieving compression between segments. [0003] 2. Description of the Prior Art [0004] In treating a bone fracture it is common practice to fasten one bone segment to the other so as to stabilize and immobilize them for the duration of the bone consolidation process. Thus there is the technique of internal fixation or direct mechanical fastening of the bone segments. [0005] Traditionally, fixation has been accomplished by variety of apparatus and techniques, the more common involving the use of metallic fastening devices such as screws, connector plates (secured to the bone by screws), pins and clips. These methods invariably involve the drilling of screw holes in the bone and the use of related equipment such as drill hole templates. [000...

AI Technical Summary

Benefits of technology

[0022] The novel fastening method involves first positioning the fractured ends of a first and a second bone segment in proximate, face-to-face relationship. The next step involves spreading apart the staple legs by a certain amount and holding the staple in the resultant tensioned configuration. The extent to which the staple legs are separated can be varied in one preferred embodiment of the invention, the induced compressive forces between the legs being proportional to the amount of displacement of the legs as the bowed portion is moved through range of motion in which elastic behavior is exhibited. In this regard it should be evident that herein lies one of the advantages of the present invention, i.e. the capability of selecting the optimal compressive force for an application by spreading apart the staple legs by a predetermined amount.

[0023] Next, as the staple is held in its tensioned configuration, it is positioned with it sharp ends forward and aligned respectively with surfaces of one bone segments and the other. Finally the positioned staple, while maintained in its tensioned configuration, is driven into the bone by percussive force, such quick application being provided by a conventional air-powered striker of a stapler according to the present invention, or by a manually stuck staple applicator according to the invention. The embedded staple legs will cause the opposing bone faces to be pressed into each other with a predetermined amount of force.

Problems solved by technology

Unfortunately this method requires the drilling of specially sloped holes, involves multiple steps and is time-consuming, and like the conventional rigid fastening techniques, requires relatively large surgical opening.

Also, the manual installation of the clip using hemostats and the like is difficult, requires meticulous skill and handling.

This design appears inherently limited regarding adjustability and maintenance of constant pressure.

The foregoing techniques involving crimpable clips all appear to be imprecise in setting up suitable compressive forces, require hole drilling and related problems, and do not lend themselves to minimizing the size of the surgical opening.

Unfortunately there is concern for trauma to the bone due to driving of the compound-shaped legs into the bone mass, and there is little apparent precision in establishing the desired compressive forces.

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