DE8016889U1 - Spacer for prosthetic vertebral body replacement - Google Patents

Description

Glawc, DeIfs, Moll & Partner - ρ 9 ^ & ⁴ / 8ο - page 3

description

The invention relates to spacers for prosthetic vertebral body replacement. It also refers to a Tool for inserting and distracting this spacer.

It is known to replace a vertebral body with a metal pin that is coated with bone cement, which can be modeled according to the shape of the vertebral body to be replaced. Finding and possibly However, fitting and inserting a fixed length pen is time consuming. It is not always possible implant the spacer during the curing time of the bone cement. But this is the prerequisite for a good bond between the metallic implant, the bone cement and the bone.

The invention is therefore based on the object of creating a spacer and a tool for implanting the same, that allows an optimal fit within a few seconds.

The solution according to the invention consists in that the spacer consists of two longitudinally movably guided to one another, is provided with cooperating latching devices, each of which has a supporting end for cooperation with an adjacent vertebral body.

The spacer according to the invention can in the collapsed state and therefore very easily to the destination and then distracted to the desired length. These processes can take place very quickly, especially within the hardening time of bone cement, so that a good bond can be achieved,

Glawe, DeIfs, MoQl P / Partner - ρ 9664/80 - page 4

The mutual guidance of the two parts of the spacer is expediently designed telescopically. According to a special feature it is provided that the rod provided on one part and that on the other Part of the intended bore of the telescopic guide have a matching oval cross-sectional shape with play, so that they can be displaced one inside the other in the longitudinal direction with the same position of their longer transverse axes; It is also provided that the rod in its cross-sectional area further away from the center and that of the bore forming part in its cross-sectional area closer to the center with interacting projections or recesses are provided, which can be converted into locking engagement by a relative rotation of the parts. To begin with, reside the two parts are in the position in which they can be displaced in relation to one another in the longitudinal direction. As soon as they are pulled out to the intended length, they are locked in this length setting by they are rotated by 90 ° relative to each other. The cooperating Projections and recesses are expediently designed as threads because they are so easiest to manufacture.

A tool for inserting and distracting the spacers is characterized according to the invention in that one pliers leg for the non-rotatable connection with one of the two parts and the other pliers leg for the rotatable one Connection with the other of the two parts is formed. This enables one of the two Parts is rotated for the purpose of locking, as long as the spacer is still held by the pliers, with the other Part of the spacer is held by the interaction with the pliers so that it does not also rotate can.

Glawe, DeIfπ, Moll & Partner - ρ 9664 / ΒΟ - i) t.-ite 5

So that the spacer can be set in the desired length : lung is held without constant exertion of force

I; wall is required, the tool is expediently even

h if equipped with a locking device.

; _; When the projections and recesses to lock the

$ ■ 'spacer are designed so that they are each

i | only in certain length settings of the spacer

Can be brought into engagement by rotation, is the locking device of the tool expediently designed so that in each case just in those length settings of the spacer engages, in which this can be locked by turning.

The invention is explained in more detail below with reference to the drawing, which illustrates an advantageous embodiment.

FIG. 1 shows a perspective overall view of the spacer with the actuating tools in a perspective view; Figures 2 and 3 are an end view and a side view of part of the spacer;

Figures 4- and 5 are an end view and a side view of the other part of the spacer and FIG. 6 shows a tool for inserting and distracting the

% Spacer.

·

The spacer consists of parts 1 and 2, each of which forms a supporting end which consists of a plate 3 and a projection M- , all of these parts being arranged concentrically and coaxially with one another.

Section 5 of Part 1 and Section 6 of Part .2 together form a telescopic guide, section 5 representing a sleeve with a guide hole, while the section 6 is a rod displaceable in this bore. Both the bore 7 in the sleeve 5 as

G] awe, Dc] fs, Mo] .1 & Partner - ρ 9664/80 - Ce j te 6

The rod 6, as best seen in FIGS. 2 and 4, also have an oval cross-sectional shape and form a fit, which allows the rod 6 to be easily moved in the bore 7 when the longer transverse axes 8 coincide. The rod is provided with threads 9 in its cross-sectional area further away from the center, while Corresponding threads are provided in the bore 7 in the area closer to the center at 10. If those lying one inside the other with matching transverse axes 8 Parts 5 and 6 rotated against each other by 90 °, so that the axes 8 are now perpendicular to one another, the threads 9 of the rod 6 engage in the threads 10. the bore 7, and therefore lock the two parts in the longitudinal direction.

To define the two axial directions, a pin 11 is provided concentrically within the bore 7, which is shown in FIG A quarter section 12 shows in the longitudinal direction. The rod 6 contains a central bore 13, the diameter of which is at least is as large as that of the pin 11 and has a stop pin 1 '+ projecting inward from the wall of the bore on. This engages when the rod 6 is inserted into the bore 7, in the quarter cutout 12 of the pin

11 a. In cooperation with the stop pin 14- with the Quarter section 12 defines two end positions for the rotary movement, the two in one end position Cross axes 8 coincide while they are perpendicular to each other in the other end position. The first-mentioned end position is the position in which the two parts of the spacer can be freely displaced against each other in the longitudinal direction are, while the other end position represents the Afretierungsstellung. The stop pin 14 is close to the open one Arranged at the end of the bore 13 and the pin 11 in the Bore 7 has essentially the same length as this bore, so that the stop pin 14 and the quarter cutout

12 of the pin 11 cooperate in every conceivable longitudinal setting of the two parts 1 and 2.

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A locking screw 15 can be provided (Fig. J), which is tightened after the two parts 1 and 2 have been rotated into the locking position to prevent accidental unlocking to prevent. As soon as the spacer is embedded in bone cement, there is a releasing relative movement locked out.

Part 2 of the spacer contains 3 near the plate a transverse bore 16, and part 1 is provided with a key hexagon 17. The spacer can therefore with the tool parts indicated on the right in FIG. 1 cooperate. A bolt 18 and a fork 19 are on the ends of a pair of pliers illustrated in FIG. 6, which are symbolized in FIG. 1 by the dash-dotted arrow 20 is. The bolt 18 fits into the bore 16 of the part 2 of the spacer, while the fork 19 fits around the section 5 can grasp under the plate 3 of part 1 of the spacer. Thus you can with the pliers shown in Fig. 6 Pull the spacer apart in the direction of arrow 20. When it has reached the desired length, the open-ended wrench will 21 is used by means of the key surfaces 17 to rotate the part 1 of the spacer by 90 °, while the part 2 by the interaction of the bolt 18 with the bore 16 is held non-rotatably.

A rotation of the two parts of the spacer is only possible if the threads of one part of the Face thread grooves of the other part in the circumferential direction. So that these positions can be found easily can, the locking device 22 of the pliers can be designed so that in each of those spreading positions a Has latching position in which the just mentioned conditions for the rotatability of the spacer are met.

The area of application of the spacer is the thoracic and lumbar spine. The indication for vertebral body replacement is for example in tumorous vertebral body destruction given. The advantage of the system can be seen in

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Glawe, DeIfs, Moll & Partner - ρ 9664/80 - page 8

that rapid implantation and distraction is possible, which is particularly important with the additional use of bone

cement is of great importance.

Example:

A hypernephroma metastasis in 4 ·. BWK led to a beginning Cross-section. After a right thoracotomy and resection of a rib, the V. azygos the door leaf-like opening of the pleura and the evacuation of the vertebral metastasis with the removal of the proximal one and distal intervertebral disc. Subsequently, in the 3 · and 5 · vertebral bodies centrally with a curved sharp spoon and one hole each and the telescopic spacer with the holding forceps on a trial basis so that the projections of the support ends engage in these holes. The position of the spacer in relation to the adjacent vertebral bodies was then checked under the image converter. If the implant fit was well, a layer of Sorbacel was then applied to the spinal cord as thermal protection. The bone cement was then introduced into the proximal and distal vertebral body holes. The spacer was inserted and distracted before cement hardening so that the pegs of the supporting ends fit well into the vertebral bodies anchored. Finally, the remaining bone cement was introduced and the vertebral body was modeled.

It is not necessary to use bone cement in all cases. In tumors with slower growth, the Possibility of using antologous bone material instead of bone cement to use.

Claims (1)

Protection claims 1. spacer for prosthetic vertebral body replacement, characterized in that it consists of two mutually movable longitudinally guided one supporting ends (3, 4) forming parts (1, 2) provided with interacting locking devices (9 »10). 2. Spacer according to claim 1, characterized in that the two parts (1, 2) are telescopic. 3. Spacer according to claim 2, characterized in that the rod (6) and the bore forming the telescopic guide (7) have an oval cross-sectional shape that fits with play, so that they are longer in the same position Transverse axes (8) are displaceable into one another in the longitudinal direction, and that the rod (6) in its cross-sectional area remote from the center (9) and the part (5) forming the bore (7) in its cross-sectional area (10) closer to the center Glawe, DeIfs, Moll & Partner - ρ 9664/80 - page 2 cooperating projections and recesses provided which can be converted into locking engagement by a relative rotation of the parts (1, 2). Mo spacer according to claim 3, characterized in that the interacting recesses and projections are designed as threads (9, 10). 5. Spacer according to claim 3 or 4, characterized in that that one of the two parts has a section (3, 5) for rotatable connection with a fork leg] one Actuating pliers and the other of the two parts a device (16) for non-rotatable connection with one has other pliers legs.