Human spine fixation template and method of making same

A method and template for making a rod to be implanted into a human for affixing the patient's spine. The template and the method consist of a metal rod covered by a flexible sleeve and end plugs which are cemented into the sleeve ends to fluid tightly encase the rod and prevent particulates from getting into the patient.

This invention relates to a human spine fixation template and method of
 making same.
 BACKGROUND OF THE INVENTION
 In the medical arts, it is common practice to affix a rod to a patient's
 spine in order to immobilize the spine in its length adjacent the affixed
 rod. In that practice, the surgeon determines the necessary length and
 configuration of a rod which is to be implanted into the patient, and that
 determination is based upon utilizing a template rod which the surgeon
 initially configures to the shape of the length of the spine which is to
 immobilized. That is, the surgeon initially bends and measures a bendable
 rod to conform to the affected part of the patient's spine. That rod
 becomes a template rod which is then utilized for the configuring of
 another rod which is to be implanted into the patient and secured to a
 portion of the length of the spine.
 In that practice, it is important that there be no foreign matter
 introduced into the patient, and thus the template rod should not be the
 source of any foreign matter deposited into the patient when the surgeon
 is configuring that template according to the shape of the patient's
 spine. However, a rod of a preferred material, such as aluminum, can
 release contaminating foreign particles into the patient's body when the
 rod is subjected to the forces and action of bending, and of course that
 is undesirable. The introduction of foreign particulates is a major danger
 and concern in the implantation of spinal rods.
 Accordingly, the present invention provides a template rod assembly which
 does not release any foreign matter into the patient, that is, the
 assembly's own flakings and the like, when it is being configured or bent
 adjacent the patient's spine. To accomplish this objective in the present
 invention, the template rod of this invention is provided with a sleeve
 which covers the rod and thereby precludes release of the particulates of
 the rod material. Such sleeve is preferably made of a silicone material
 which can be snugly positioned over the rod, and two end plugs are
 utilized for snugly sealing the assembled rod and sleeve at the ends of
 the assembly. As such, the template rod is fully protected and can be bent
 without leaving any foreign particles in the patient.
 The present invention also includes the method of accomplishing the
 aforementioned and to do so in a manner which provide a a protected
 template rod and does so in an efficient and reasonably cost-effective
 manner.
 Still further, the assembled rod and sleeve of this invention present
 incremental length indicia affixed along the length of the rod so the
 surgeon can determine the overall length, as well as the location, for the
 bends of the template rod. With that information, the surgeon can then use
 the template to select a final rod and to bend the final rod to conform to
 the length and configuration of the template rod and then implant the
 final rod into the patient.
 In accomplishing all of the foregoing, the present invention provides the
 coextensive length of an assembled rod and sleeve with two end plugs which
 extend within the respective opposite ends of the sleeve to render the
 entire assembly of the rod, sleeve, and the two end plugs fluid and
 particle-release tight, all so that no fluid nor particulate can pass to
 of from the interior of the assembly. In that regard, the present
 invention has the two end plugs snugly assembled with the sleeve. Also,
 the two plugs serve to indicate the respective incremental length of the
 assembly at its opposite ends so that the overall length of the assembly
 includes the end plugs, and those two end plugs conform to the opposite
 end length increments along the length of the assembly.
 The sleeve is of a transparent material, and thus indicia of length
 measurement on the rod can be seen through the encasing sleeve. Also, the
 plugs can be made of the same material as that of the sleeve to thus be
 non-offensive to the patient where the material is silicone or the like.
 The assembly of the three components of the rod and the sleeve and the two
 end pugs can be snugly assembled, as mentioned above, without the need of
 any tools or special skills.

DESCRIPTION OF THE PREFERRED EMBODIMENT AND THE METHOD
 There is a rod 10 which is preferably of aluminum material which can be
 bent by a surgeon's finger pressure while the rod is positioned adjacent
 the patient's exposed spine. As such, the configuration of the rod 10
 along its length may have compound bends or several bends therealong to
 conform to the patient's spine which is ultimately to be immobilized or
 fixed by another rod which will be made according to the configuration of
 the template rod 10. As such, the procedure is standard and well known by
 those skilled in the art, and the final rod which is to be implanted is
 not shown herein, but, as mentioned, is well known to those skilled in the
 art.
 The rod 10 has a longitudinal extent throughout its length, and it has the
 incremental distance markings with corresponding indicia, such as the
 numbers 1 through 14 as shown in FIG. 2. The indicia guides the surgeon in
 establishing the location of the bends for the purpose of finally
 formulating the final rod which is not shown herein. The rod 10 has the
 equally spaced indicia designated 11 disposed therealong.
 The rod 10 extends between its opposite ends 12 and 13, and it is shown in
 straight, and thus non-bent configuration, throughout its length and along
 its longitudinal axis of its length. The rod 10 is of a cylindrical shape
 throughout its length and is of only one continuous cylindrical shape and
 cross-sectional diameter through its entire length. As shown, it is in the
 condition prior to when the surgeon shapes it to conform to a patient's
 spine to serve as a template rod. The rod 10 is formed by machining and it
 is annealed, and it can have a black anodized finish.
 The distances between the consecutive markings between "1" and "14" are
 preferable all the same. However, the rod lengths from the markings "1"
 and "14" to the respective adjacent very ends 14 and 16 of the opposite
 ends of the rod 10 are each of a dimension less than the distances between
 the markings "1" and "14", and those lengths are designated 17. However,
 the end lengths 17 are more than one-half the distances between each two
 consective ones of the markings shown, and in fact, are approximately
 three-quarters the length of those distances between every two consecutive
 markings.
 A tubular cover 18 is of a clear or transparent elastomer material such as
 silicone and it is of a length slightly longer than the length of the rod
 10. Also, the cover 18 is a sleeve which slides over the rod 10 to snugly
 encase the rod 10 along its entire length. However, the markings are
 visible through the cover 18, as seen in FIG. 4. The interior diameter of
 the cover at 19 is substantially the same as the exterior diameter of the
 rod 10, so the cover 18 is snug on the rod 10 and will not slide
 therealong to a degree that it will tend to slide off the rod 10 when the
 rod 10 is subjected to forces of bending or the like.
 Two end plugs 21 complete the assembly, and they are positioned as shown in
 FIG. 4. The plugs 21 are cemented into the assembly and are fluid tight
 with the sleeve 18 to thereby provide a completely enclosed casing for the
 rod 10. The plugs are of a cylindrical shape with a diameter designated at
 22 and that is substantially the same size as the interior diameter 19 of
 the sleeve. Also, the plugs are of an axial length designated at 23. As
 mentioned, the length of each rod end 12 and 13 from the adjacent marking
 11 at the respective end 12 and 13 is less than the distance between
 consecutive markings 11, and the plug length 23 and the rod length 12 or
 13 together are respectively of the length which is the same as that
 between the consecutive markings 11. That is, the respective lengths of
 the rod ends 12 and 13, along with the respective plug lengths 23, present
 the exact distance as that between the consecutive markings 11. Thus, the
 assembly has the uniform distances between the consecutive markings 11 and
 also between the markings "1" and "14" and the assembly respective ends,
 as designated 24.
 FIG. 4 fragmentarily shows the assembly and the features of the encasement,
 the cemented positioning of the plugs, and the uniformity of the distances
 between the markings along the entire assembly and completely to the
 assembly ends 24. No metal parts are required to form the encasement which
 consists only of the sleeve 18 and the two plugs 21.
 Throughout this description, the method is also described and disclosed to
 one skilled in the art, and it is a part of this invention. The sleeve is
 stretched over the rod 10 and the ends of the sleeve extend beyond the
 respective ends of the rod to provide a cylindrical cavity at each end.
 The plugs can be of silicone material and glue is applied to them and they
 are then inserted into the respective sleeve cavities and form a
 fluid-tight bond with the sleeve. There could be a length of the plug
 material in the form of a cylindrical rod of a length greater than that of
 each plug, and an end of that rod could have glue applied thereto, and the
 rod, along with the glued end, could then be maneuvered to have the plug
 inserted into its cavity in the sleeve. The surplus and protruding
 remainder of the rod could then be cut off, leaving the cemented plug in
 its place.
 With the template and its bent configuration as formed by the surgeon, the
 final rod or fixation member can be configured in accord with the
 incremental markings displayed along the template, and bending can be done
 manually or with tool assist. The assembly provides a template rod which
 is flexible throughout its entire length and it is soft and resilient
 throughout its length. It will not press upon the patient's body to cause
 damage thereto. Also, it can be bent at the ends of the assembly because
 there is no rigidity at the ends.