DE10003050C2 - Surgical dilatation instrument and spacer for use with such - Google Patents

Description

The present invention initially relates to a surgeon cal dilatation instrument according to the preamble of the An saying 1.

Such a dilation instrument is used e.g. B. use it det that is too close together if the intervertebral disc is damaged to move lying vertebral bodies away from each other, that is Intervertebral disc compartment to expand into this subsequently z. B. to use a cage.

So far there has been banding for this dilation process benfach no special instruments. Instead be z. B. spatula used as a dilation instrument. On spatulas known from the market essentially have one rectangular dilation section, the side edges of which are rounded. The dilation section is under one Angle formed on a holding section that the surgeon holds in hand when used. By swiveling of the holding section results in a twist around Longitudinal axis of the dilation section, making two too tight adjacent vertebral bodies are levered apart can.

However, the known dilation instrument has the disadvantage that there is an offset or a Cantilever of the two vertebrae to be pressed apart can come. In addition, when using the known dilatation instrument again and again to damage vertebral body injuries and injuries in the area  the vertebral body of existing soft tissue.

DE 195 15 626 A1 relates to an instrument for positioning kidneys of working sleeves during endoscopic operations, DE 30 25 785 A1 a dilator for introducing Endoscopes and the US 48 62 891 instruments for sequencing tial opening of percutaneous tissue. US 45 73 448 describes an instrument for decompression of Hernias of the lumbar spine, WO 93/04652 such for arthroscopic cervical discectomy and EP 0 875 219 A2 a device for the injection of an elasti spinal implant.

The present invention therefore has the task of a dila creation instrument with which two side by side lying vertebral bodies can be moved away from each other, without causing a lateral displacement of a vertebral body comes to an adjacent vertebral body and without that injuries to the tissue surrounding the vertebral body are to be feared.

This object is achieved by the Dila specified in claim 1 tion instrument solved.

According to the invention it was found that in the conventional Chen dilation instrument despite the existing rounding the edges between the narrow sides and the Hook the long sides of the dilation section to the bone can. This causes rotation of the dilatati section to the lateral relative movement of the two Vertebrae to each other. Due to the right despite the rounding relatively narrow edges and the resulting strong line-like contact, relatively high forces occur and it there is a risk that the vertebral body is damaged or Soft tissue is squeezed and there are corresponding injuries  comes.

These problems are caused by the approximately elliptical cross Avoid the sectional shape of the dilation section. At a such cross section there are no more edges in the above Sense. Instead, the dilation section of the he dilation instrument according to the invention de peripheral surface without discontinuities due to edges where areas of different curvature in the peripheral surface has, but which merge continuously. The surgeon can therefore use the dilation instrument when in use  twist relatively easily around its longitudinal axis, so that the lateral surface of the dilation section during the rotational movement without getting caught on the vertebral bodies long glides and this due to the elliptical cross shape can move away from each other.

The operator has the lowest forces, of course, at ei nem very small aspect ratio of the semiaxes bring. In this case, however, is the way by which the vertebral body with a 90 ° rotation of the dilatation struments can be moved apart from each other, only very low. If the aspect ratio is too large, those Be range of the elliptical cross-sectional shape, which a rela tiv strong curvature, so "pointed" that the contact Forces increase strongly and the desired gliding effect is no longer certain, so that it still leads to a ver hook and a corresponding undesirable lateral re come relative movement between the two vertebral bodies can. Within the range of lengths according to the invention ratios of the semiaxes from 1: 1.5 to 1: 2.1 are each but achieved good results in every respect.

Advantageous developments of the invention are in Unteran sayings.

According to the development according to claim 2, the length is ratio of the semiaxes of the elliptical cross section of the Dilatation section in the range of 1.7 to 1.9. In this Area are the forces and to be applied by the surgeon thus also that of the dilation instrument when in use forces exerted on the vertebrae are still relatively low, although with a 90 ° rotation of the dilation instrument already an expansion of the between the vertebral bodies before existing gap by 70 to 90% is possible. Only with one Length ratio of the semiaxes of the elliptical cross section  of the dilation section above the specified Range increases the forces to be applied by the surgeon and the risk of injury to the vertebral body and tissue noticeably.

The flattening specified in claim 3 at the apex score the cross-sectional contour of the dilation section improves the operation of the Instru again.

According to claim 4, the dilata is particularly preferred tion section is releasably connected to the holding section. In some cases, it may be desirable to post of the dilation, the dilation section in the To leave gap between the two vertebral bodies then in another place with a second dilatati onsinstrument in the same gap between two vertebrae to set. Such an approach can e.g. B. at be advised of a starting position in which the two Vertebral bodies are at an angle to each other, that is one of the vertebral bodies in relation to the other vertebral body is arranged at an angle.

An example of such a releasable connection between Dilatation section and holding section is in claim 5 specified: Then there is a pin in one of the sections with an external toothing in one in the other Section existing recess with an internal toothing intervenes. By means of this toothing, the holding section in a relatively fine angle grid with the dilatation instruments. The operator therefore does not have to Spend time finding the correct relative angular position of the Holding section with respect to the dilation section Connect these two sections together the. Furthermore, such gearing can also result in high  Torques are transmitted safely.

To the releasable dilation section from the gap between being able to pull out two vertebrae again proposed according to claim 6 that in the recess of the other section locking recesses are available in the existing on and off on the pin of the first section mobile locking cams can intervene.

Alternatively, the coupling of the holding section with the Dilatation section also through a bayonet connection follow (claim 7).

As stated above, the dilation rotates ideally during the dilatation process its longitudinal axis, with no lateral component of motion. A such movement is facilitated if, according to claim 8 Holding section with a detachable twist grip one is essentially perpendicular to the tool longitudinal axis extending lever portion comprises. advantageously, are several lever sections z. B. arranged in a cross shape, so that the surgeon can move the dilatation of the dilatati onsinstruments by simply turning his hand can effect. Removability of the twist grip makes it easier the manageability of the dilatation instruct management.

One possibility for a safe transmission of the torque ment from the twist grip on the holding section is claimed 9 specified: Then the holding section and the Twist grip over a toothing analogous to claim 5 rotatably together. In claim 5 it was stated that in an Ab cut a spigot with external teeth and the other Section a recess with internal teeth existing is in which the pin engages.  

The development of the invention specified in claim 10 facilitates lateral movements of the stop for the surgeon cuts and improves the field of vision into the operating area.

The invention further relates to a spacer for Ver application with a dilation instrument according to one of the applications Proverbs 1 to 10. This serves the intradiscal space between the two vertebrae after dilatation to keep it open so that work can be done in it can (e.g. to insert a cage).

Such a spacer has, as in claim 11 is given, one over the holding section and the dilata tion section of the surgical dilatation instrument slide-on tubular area and at least one extending axially from its lateral surface cut that with two spaced apart areas can be placed on the end faces of adjacent vertebral bodies. The distance between the areas is approximately as large as the largest transverse dimension of the dilation section of the dilation instrument (this corresponds to double Length of the major semi-axis of the ellipse). At the same time however, this distance may be less than the inside width of the tubular area, so z. B. one through the tubular Instrument inserted in the area up to the bone surface chen the vertebral body can reach.

After dilation is done through the distance section the distance between the vertebral bodies maintained even when the dilation section of the Dilation instrument was removed. simultaneously the mutually facing surfaces of the vertebrae remain accessible to be edited if necessary.  

The handling of the spacer, in particular together Menhang with the holding section is through the training relieved according to claim 12.

The present invention also relates to a set of surgical dilation instruments according to one of the An Proverbs 1 to 10. According to claim 13, this sentence includes one Majority of dilatation instruments, the dilatationab cut different dimensions, but the same neck have axis ratios, the length of the small Semi-axis of the next largest dilation section approximately the length of the major semiaxis of the next smaller dilata tion section corresponds. With such a sentence by Di latation instruments is due to the successive use of the next major dilatation instrument the expansion of the Intradiscal space up to a multiple of the length ver Ratios of the semiaxes of the dilation sections possible.

Particularly preferred dimensions of the dilation sections of a sentence are mentioned in claim 14.

In the following the invention will be explained with reference to an embodiment game with reference to the drawing in detail tert. In this show:

Fig. 1: a side view of a dilatation instrument with a dilatation section, a Halteab section and a twist grip;

Fig. 2 is a sectional view taken along the line II-II of Fig. 1;

Fig. 3 is a sectional view taken along the line III-III of Fig. 1;

Fig. 4 is a sectional view taken along the line IV-IV of Fig. 1;

FIG. 5 is a sectional view taken along line VV of FIG. 1;

Fig. 6 is a side view of a spacer element;

Fig. 7: a sectional view along the line VII-VII of Fig. 6; and

FIG. 8 is a plan view of the spacer element of Fig. 6.

In Fig. 1, a total of Dilatationsinstrument bears the reference numeral 10. It comprises a dilatation section 12 , a straight line with the dilatation section 12 ver bindable holding section 14 and a section with the Halteab 14 connectable rotary handle 16th

The dilatation section 12 has an almost elliptical cross-section (see FIG. 2) and is somewhat flattened in the apex area of its cross-sectional contour. The ratio of the major semiaxis a to the minor semiaxis b of the cross section of the dilatation section 12 is 1.8, as can be seen from FIG. 2. At its front end 22 , the dilation section 12 is also elliptically rounded in the longitudinal direction.

In the end face 23 of the dilatation section 12 facing the holding section 14 , a blind bore 24 is introduced, the inner circumferential wall of which has axially parallel toothing 26 (see FIG. 3). At the bottom of the blind bore 24 , somewhat spaced therefrom, an annular locking recess 28 is made in the inner peripheral wall of the blind bore 24 . The function of the internal toothing 26 of the blind bore 24 and the locking recess 28 is discussed in detail below.

The holding section 14 of the dilatation instrument 10 comprises an overall circular cylindrical central body 30 , the diameter of which corresponds approximately to the small semiaxis b of the dilatation section 12 . On the Dilatationsab 12 facing end face 31 of the central body 30 , a pin 32 is formed, the length of which corresponds approximately to the depth of the blind bore 24 . The diameter of the pin 32 corresponds approximately to the diameter of the blind bore 24 in the dilation section 12 . The outer circumferential surface of the Zap fens 32 of the holding portion 14 has a circumferential Ver teeth 34 , which is designed so that it can cooperate with the inner teeth 26 of the blind bore 24 . This creates a rotationally fixed connection between the holding section 14 and the di latation section 12 in the assembled state.

From the circumferential surface of the pin 32 extend in the loading area of the end facing the dilatation section 12 , but somewhat spaced therefrom, four detent cams 36 distributed over the circumference radially outward. By pressing two actuating elements 38 , which are seated in recesses 40 in the central body 30 , the locking cams 36 can be completely sunk in the pin 32 in a manner not of interest here. If no pressure is exerted on the actuating elements 38 , the locking cams 36 are biased by spring elements, not shown, into the extended position shown in FIG. 1 and in FIG. 4.

The long sides of the locking cams 36 facing the dilatation section 12 have an insertion bevel 42 . Overall, the position and shape of the locking cams 36 is selected so that they cooperate with the annular locking recess 28 in the pocket bore 24 in the dilation section 12 and can axially lock the holding section 14 with the dilation section 12 .

In an embodiment not shown, the Coupling the holding section with the dilation section also take place via a bayonet connection.

In the end face 44 of the holding section 14 facing away from the dilation section 12 there is a blind bore 46 with internal teeth 48 , analogous to the blind bore 24 in the dilated section 12 . In this blind hole 46 , a molded on the rotary handle 16 pin 50 can be introduced to who, which also has teeth 52 on its peripheral surface. This ensures together with the internal toothing 48 in the blind hole 26 for a rotationally fixed connec tion of the pin 50 in the blind hole 46 when the pin 50 is inserted into the blind hole 46 .

The pin 50 is formed on the end face 54 of the base portion 56 of the rotary handle 16 facing the holding portion 14 . The base part 56 has a total circular cross section and the same outer diameter as the central body 30 of the holding section 14 and the dilatation section 12 (see FIG. 5). On the base part 56 a perpendicular to the longitudinal axis of the dilatation element 10 extending lever portion 58 is formed. In egg nem embodiment not shown, a total of at least four radially outwardly extending lever portions are integrally formed on the Ba sisteil, as in a rotary handle of a tap.

In FIGS. 6, 7 and 8, a spacer element 60 is shown for use with the Dilatationsinstrument 10th

The spacer element 60 comprises a tubular region 62 with a circular cross section, the inner diameter of which is larger than the larger semi-axis a of the dilatation section 12 . The length of the tubular portion 62 is a little less than the length of the central body 30 of the holding portion 14 . Are at its rear end in the rohrför-shaped portion 62 has two diametrically opposed recesses 63 Läng Liche present which extend up to the vicinity of the rear edge of the tubular portion 62 of its front end.

On the tubular region 62 , two plate-like Di punch sections 64 are formed, which are diametrically opposite and extend from the outer surface of the tubular region 62 in the axial direction. The length of the spacer sections 64 corresponds approximately to the length of the corresponding dilatation section 12 . The spacer sections 64 have an elongated shape and have an elliptical edge contour 66 at their left end in FIG. 6. With the front edge of the tubular region 62 , the spacing sections 64 are connected by a relatively narrow material web 68 .

The height of the two spacer sections 64 is approximately as large as the largest transverse dimension of the elliptical section 18 from the dilatation section 12 , thus corresponds approximately to twice the value of the large semiaxis a of FIG. 2. However, the spacer sections 64 are less high than that Inner diameter of the tubular portion 62 . Thus, the inner diameter of the tubular region 62 is in any case greater than twice the length of the half axis a of the elliptical cross section of the dilatation section 12 of the dilatation instrument 10 .

Reinforcing ribs 70 run from the upper longitudinal side to the lower longitudinal side of each spacer section 64 , which in an exemplary embodiment not shown can also be designed simply as material beads with which the buckling stiffness of the spacer sections 64 is increased.

The dilatation instrument 10 is inserted as follows: First, the pin 32 on the central body 30 of the holding section 14 is inserted into the blind bore 24 in the dilatation section 12 . As soon as the locking cams 36 come into contact with the edge formed between the blind bore 24 and the end face 23 , they are moved radially inward due to the insertion bevel 42 and disappear in the pin 32 . When the pin 32 of the holding section 14 is fully inserted into the blind bore 24 in the dilation section 12 , the locking cams 36 snap into the annular locking recess 28 in the blind bore 24 due to the spring tension. The holding section 14 is thus non-rotatably and axially secured ge connected to the dilatation section 12 .

The surgeon now grips the holding section 14 and introduces the dilation section 12 into the intradiscal space between two vertebrae. He holds the holding section 14 so that the small semiaxis b of the dilation section 12 runs essentially parallel to the spinal axis (the spine and a corresponding intradiscal space are not shown in the drawing). The insertion of the dilatation section 12 into the intradiscal space is facilitated by the elliptical rounding present at its front end 22 .

As soon as the dilatation section 12 is fully inserted into the traditional space, the operator places the rotary handle 16 on the holding section 14 by inserting the pin 50 on the rotating handle 16 into the blind bore 46 in the central body 30 of the holding section 14 . Then he engages the lever section 58 of the rotary handle 16 and rotates the sen about the longitudinal axis of the dilatation instrument 10 by an angle of approximately 90 °. The outer surface of the dilatation section 12 slides along the bone walls of the vertebrae and moves them away from each other.

Since the dilatation section 12 due to its almost elliptical cross-sectional shape and due to the selected length ratio of the elliptical semiaxes a and b does not have any edges, there is no jamming of the dilatation instrument 10 with the vertebral bodies during the rotary movement and thus also no lateral relative movement between the two vertebrae. Because of the missing edges on the dilatation section 12 , there is also no excessive local stress on the vertebral bodies, thereby preventing damage to the vertebral bodies during the dilatation process.

After the expansion of the intradiscal space has taken place, the surgeon removes the twist grip 16 of the dilatation instrument 10 and pushes the spacer element 60 with the sections 64 from 64 above the central body 30 of the holding section 14 . He pushes the spacer element 60 until the spacer sections 64 are at the level of the Dilatationsab section 12 in the intradiscal space between the two vertebrae. He aligns the spacer 60 by rotating it accordingly so that the Dist 64 sections are arranged substantially perpendicular to the vertebral bodies.

Now he can pull the dilatation section 12 out of the intradiscal space via the holding section 14 without the two vertebral bodies approaching again. He can move laterally due to the lateral recesses 63 in the tubular loading area 62 of the spacer 60, the holding section 14 , which among other things facilitates the extraction of the dilatation section 12 .

The operator can now carry out work in the intradiscal space through the tubular region 62 of the spacer element 60 . Since the inner diameter of the tubular loading area 62 is larger than the height of the spacer sections 64 , it can be, for. B. insert a tap (not shown) through the tubular area 62 into the traditional space and work with the tap on the bone surfaces of the vertebral bodies.

Possibly. However, instead of (already now) inserting the spacer element 60 , he can press the actuating elements 38 on the central body 30 of the holding section 14 , as a result of which the latching cams 36 move radially inward and thereby the axial locking of the holding section 14 with the diating section 12 to solve. The holding section 14 can then be pulled out while the dilation section 12 remains in the intradiscal space. The surgeon can now connect the holding section 14 to another dilation section 12 and penetrate it into the intradiscal space at another point.

If the surgeon has a set with a plurality of dilatation instruments 10 with dilatation sections 12 which have different dimensions, but the same aspect ratios of the semiaxes, and in which the small semiaxis of the next largest dilatation section has approximately the length of the large semiaxis of the next smaller dilatation section , then he can also connect the holding section 14 to a larger dilatation section 12 , penetrate the latter, for example, into the intradiscal space at this point and enlarge the already expanded intradiscal space again by a corresponding rotary movement.

Claims (14)

1. Surgical dilatation instrument for use in spinal surgery with a non-round dilatation section and a holding section, characterized in that the dilatation section ( 12 ) has a loading area with an approximately elliptical cross-sectional shape with an aspect ratio of the semiaxes, which is in the range of 1: 1, 5 to 1: 2.1. 2. Surgical dilatation instrument according to claim 1, characterized in that the length ratio of the semiaxes of the elliptical area of the dilatation section ( 12 ) is in the range of 1: 1.7 to 1: 1.9. 3. Surgical dilatation instrument according to one of claims 1 or 2, characterized in that the curvature of the cross-sectional contour of the elliptical region of the dilatation section ( 12 ) is somewhat flattened at its apex relative to the ideal elliptical shape. 4. Surgical dilatation instrument according to one of the preceding claims, characterized in that the dilatation section ( 12 ) can be releasably connected to the holding section ( 14 ). 5. Surgical dilatation instrument according to claim 4, characterized in that the dilatation section ( 12 ) and the holding section ( 14 ) by an in one section ( 14 ) existing pin ( 32 ) with an external toothing ( 34 ) which in one in the other section ( 12 ) Existing recess ( 24 ) engages with an internal toothing ( 26 ), are rotatably connected to each other. 6. Surgical dilatation instrument according to claim 5, characterized in that in the recess ( 24 ) of the other section ( 12 ) latching recesses ( 28 ) are present, in which the pin ( 32 ) of the first section ( 14 ) existing retractable and extendable Can engage locking cams ( 36 ). 7. Surgical dilatation instrument according to claim 5, characterized in that the dilatation section ( 12 ) and the holding section ( 14 ) are coupled by a bayonet connection. 8. Surgical dilatation instrument according to one of the preceding claims, characterized in that it comprises a detachable rotary handle ( 16 ) with at least egg nem extending substantially perpendicular to the tool longitudinal axis lever portion ( 58 ). 9. Surgical dilatation instrument according to claim 6, characterized in that the holding section ( 14 ) and the rotary handle ( 16 ) via a toothing ( 48 , 52 ) cooperate in a rotationally fixed manner as in claim 4. 10. A surgical Dilatationsinstrument according to any one of the preceding claims, characterized in that the maximum width of the holding portion (14) corresponds approximately to the smaller half-axis of the Dilatationsabschnitts (14). 11. Spacer element for use in a surgical dilatation instrument according to one of the preceding claims, characterized in that there is a tubular region ( 62 ) which can be pushed over the holding section ( 14 ) and the dilatation section ( 12 ) of the surgical dilatation instrument ( 10 ) and at least one from the lateral surface of the axially extending spacer portion ( 64 ), which can be placed with two spaced apart areas on the end faces of adjacent vertebral bodies, the distance between the areas being approximately as large as the largest transverse dimension of the Dilatationsab section ( 12 ), however smaller than the inside width of the tubular area ( 62 ). 12. Spacer element according to Anspuch 10 , characterized in that the tubular region at its end by the Di punch sections ( 64 ) remote end has at least one lateral recess ( 63 ). 13. Set of surgical dilation instruments after one of claims 1 to 7, characterized in that that he had a variety of dilation instruments around summarizes whose dilatation sections differ measurements, but the same semi-axis ratios point, the length of the small semiaxis of the the next largest dilation section approximately in length the major semiaxis of the next smaller dilation section corresponds. 14. Set of surgical dilatation instruments according to claim 13 , characterized in that it has dilatation sections which are approximately 26, 28, 30 and 32 mm long and whose larger semi-axes are approximately 8, 10, 12, 14 and 16 mm long.