WO2007068128A1

WO2007068128A1 - A pair of tongs apt for soft tissue spreading

Info

Publication number: WO2007068128A1
Application number: PCT/CH2005/000753
Authority: WO
Inventors: Martin Kaufmann; Daniel Fluri
Original assignee: Synthes Gmbh
Priority date: 2005-12-15
Filing date: 2005-12-15
Publication date: 2007-06-21

Abstract

A pair of tongs (1) apt for soft tissue spreading and comprising A) a first lever (2) and a second lever (3) being joined in a mutually rotatable manner by means of a swivel joint (10); B) a reversibly engageable locking mechanism (12) by means of which said first and second lever (1;2) are reversibly fastenable in a desired mutual position; whereby C) said first and second lever (1;2) include a handle portion (4;5) each by means of which said pair of tongs (1) may be grasped by one hand; D) said locking mechanism (12) includes a release member (14) by means of which said locking mechanism (12) is disengageable and which is disposed at one of said first and second levers (2; 3) between the respective handle portion (4;5) and said swivel joint (10); and E) a resilient member (7) apt to spread said first and second lever (1;2) when said locking mechanism (12) is in a disengaged position.

Description

A pair of tongs apt for soft tissue spreading

FIELD OF THE INVENTION

The present invention relates to a pair of tongs apt for spreading soft tissue.

BACKGROUND OF THE INVENTION

In orthopaedic surgery, e.g. in case of bone plates being fixed to a bone, minimal invasive treatments are frequently performed. Often bone screws are percutaneously inserted or removed through small stab incisions. Such procedures often require the assistance of a second person that opens the incision by means of a conventional tissue retractor so that the surgeon may perform the desired surgical treatment. However, the relatively small stab incisions in case of minimal invasive surgery hinder the assistant from attaching the tissue retractors which may cause tissue injuries.

A surgical lamina spreader instrument for treatment of the spine is known from US 5,019,081 WATANABE. This known spreader instrument comprises a ratcheting device to fasten the levers of the spreader instrument in a desired mutual position. Furthermore, a leaf spring is provided by means of which the two levers are spreaded when the ratcheting device is disengaged. This known spreader instrument has the disadvantage that the ratcheting device must be operated with a second hand.

A pair of tongs with tissue-gripping pincer points that are held in their position relative to each other by means of a ratchet bar assembly is known from US 5,997,545 DOHERTY. The ratchet bar assembly comprises a telescoping cross bar which moves against the restraining force of an extension spring to register the spreading force exerted on the pincer arms by the tissue under tension. The disadvantage of these known tongs is that the surgeon needs one hand to move the handles of the tongs relative to each other and additionally needs a second hand to lock or unlock the ratchet bar assembly in order to fix the pincers in their gripping position.

Therefore, it is a principal objective of the present invention to provide a pair of tongs being apt for soft tissue spreading permitting a single-hand operation of the levers as well as of a locking mechanism by means of which the levers may be reversibly locked in a desired mutual position. Furthermore, the levers shall be resiliently spread apart when the locking mechanism is in its disengaged position.

SUMMARY OF THE INVENTION

The present invention is related to a pair of tongs apt for soft tissue spreading. A first lever and a second lever are jointedly connected in a mutually rotatable manner by means of a swivel joint. In order to lock the two levers in a desired mutual position, i.e. to keep the soft tissue abutting the front ends of the levers apart at a desired distance a locking mechanism is attached which connects the first and second lever and by means of which said first and second lever are reversibly fastenable in a desired mutual position. Each of said first and second lever includes a handle portion directed towards the rear ends of the first and second levers such that said pair of tongs may be single- handedly grasped. Furthermore, the locking mechanism is provided with a release button which is located at one of said first and second levers between the respective handle portion and the swivel joint such permitting an actuation of the release button with the same hand as the handle portions are being grasped. Upon actuating the release button the locking mechanism is brought in its disengaged position. The pair of tongs according to the invention further comprises a resilient member by means of which said first and second levers are being resiliently spread apart when said locking mechanism is disengaged.

The advantages achieved by the pair of tongs according to the invention are essentially

a) the possibility of a secure intraoperative single-handed operation due to the location of the release member relative to the handles; and b) a self-acting spreading of the levers when the locking mechanism is in its disengaged position.

In a further embodiment said locking mechanism comprises a retention means permitting to reversibly keep the release member in a position where said locking mechanism is permanently disengaged. Thus, the advantage may be achieved that soft tissue may be spreaded resiliently and the incision may be kept open through application of a tension by means of the resilient member. For this purpose the resilient member may be configured as a compression or tension spring depending on the configuration of the first and second lever.

In another embodiment said first and second lever comprise a free end each being located oppositely to the handle portion. Furthermore, the free ends are provided with attachment means, e.g. a snap-fit by means of which a pair of soft tissue retracting blades is attachable to said free ends. This allows to mount different pairs of soft tissue retracting blades (e.g. different length, shape) in order to better adapt said pair of tongs to a particular use.

In yet another embodiment said attachment means comprise a detent portion configured to form a releasable fixation to a soft tissue retracting blade. Thus, the selected soft tissue retracting blades can easily be attached to the free ends of the pair of tongs and are being fixable, e.g. by means of a click lock.

In still a further embodiment said locking mechanism comprises a toothed bar with a longitudinal axis, whereby a first end portion of said toothed bar is hingedly connected to one of said first and second levers while a second end portion of said toothed bar is connected to the release member in such way that the toothed bar may slide parallel to its longitudinal axis within the release member when the locking mechanism is in its disengaged position.

The assembly for spreading soft tissue according to the invention essentially comprises a pair of tongs and a set of soft tissue retracting blades.

In a preferred embodiment of the assembly said set of soft tissue retracting blades comprises M > 2 pairs of soft tissue retracting blades each pair having a different length.

In a further embodiment of the assembly a set of trocars is included, each of said trocars being insertable between blades of a corresponding pair of soft tissue retracting blades. Thus, the advantage is achieved that a modular system of soft tissue spreaders is provided permitting a selection of suitable soft tissue retraction blades as well as of a trocar which is appropriate to the selected pair of soft tissue retraction blades. Short description of the use of an assembly for soft tissue spreading comprising a pair of tongs including soft tissue retracting blades with the following method:

- The surgeon performs a stab incision at the body portion of a patient to be treated.

- Subsequently, the operator selects a pair of soft tissue retraction blades being appropriate to the soft tissue and the surgical procedure to be performed and attaches the selected pair of soft tissue retraction blades to a pair of tongs.

- Then, the operator selects a trocar which is appropriate to the pair of soft tissue retraction blades and inserts the pair of soft tissue retraction blades together with the trocar into the stab incision by means of the pair of tongs untU the desired insertion depth is reached.

- The operator then spreads the pair of soft tissue retraction blades and subsequently removing of the trocar such that further steps concerning insertion or removal of surgical devices, e.g. bone screw through the opening between the soft tissue retraction blades may be performed.

Further objects and advantages of the invention will become apparent from the following description when read with reference to the accompanying drawings which illustrate several embodiments of the invention. In the drawings:

Fig. 1 shows a perspective view of an embodiment of the pair of tongs according to the present invention;

Fig. 2 shows a magnified cross section along the line Il - Il in fig. 1 ;

Fig. 3 shows a perspective view of an assembly for soft tissue spreading according to one embodiment of the invention;

Fig. 4 shows a perspective view of a further embodiment of the pair of tongs according to the invention; and

Fig. 5 shows a cross-sectional view along the line III - Ml in Fig. 5. The pair of tongs 1 shown in fig. 1 essentially comprises a first lever 2 and a second lever 3 being joined in a mutually rotatable manner by means of a swivel joint 10, said first and second lever 2;3 each having a handle portion 4;5 and oppositely arranged a free end 8;9 being provided with attachment means 17 by means of which soft tissue retracting blades 18 are attachable to said free ends 8;9 e.g. by means of a snap-fit. Furthermore, a reversibly engageable locking mechanism 12 is provided by means of which said first and second lever 1 ;2 are reversibly fastenable in a desired mutual position. The locking mechanism 12 includes a toothed bar 13 and a release member 14 with a transverse opening 24 (fig. 2) formed as a leadthrough for the toothed bar 13, the wall of said transverse opening 24 having serrations 22 (fig. 2) which are in engagement with the toothed bar 13 when said locking mechanism 12 is in its engaged position.

The first end portion 15 of the toothed bar 13 is connected to the first lever 2 by means of a hinge joint 21 having a rotation axis perpendicular to a plane defined by the first and second lever 2;3. The second end 16 of the toothed bar 13 penetrates the second lever 3 such that the longitudinal axis 11 of the toothed bar 13 extends between the swivel joint 10 and the handle portions 4;5 of the first and second lever 2;3. The release member 14 is configured as a flush type push-button which is integrated in the second lever 3. Furthermore, the resilient member 7 is configured as a helical compression spring apt to spread said first and second lever 2;3 when said locking mechanism 12 is in a disengaged position.

The locking mechanism 12 is illustrated in more detail in Fig. 2. A pocket hole 32 penetrates into the second lever 3, whereby the longitudinal axis 31 of the pocket hole 32 is parallel to the swivelling axis 6 of the swivel joint 10 (fig. 1). The release member 14 which is configured as a flush type push-button is inserted in the pocket hole 32 and has a longitudinal transverse opening 24 apt as a leadthrough for the toothed bar 13, whereby the long axis of said longitudinal transverse opening 24 extends parallel to the longitudinal axis of the pocket hole 32. Furthermore, the wall of said transverse opening 24 is provided with serrations 22 at a portion of its periphery towards the front end 33 of the release member 14, whereby said serrations 22 engage the corresponding teeth 25 of the toothed bar 13 when the locking mechanism 12 is in the engaged position, i.e. when the release member 14 is not pressed down. The opposite peripheral portion of the wall of the transverse opening 24 is smooth such that upon pressing the release member 14 down, i.e. further into pocket hole 32 the serrations 22 disengage from the teeth 25 of the toothed bar 13 and the locking mechanism 12 is put in its disengaged position such that the toothed bar 13 may slide parallel to its longitudinal axis 11 through the transverse opening 24 in the release member 14 as well as through the transverse bore 23 in the second lever 3. By means of a compression spring 36 coaxially disposed in a recess 34 at the front end 33 of the release member 14 and abutting the bottom 35 of the pocket hole 32 the release member 14 is pushed into the position in which the serrations 22 engage the teeth 25 of the toothed bar 13. The serrations 22 as well as the teeth 25 are asymmetrically configured, i.e. the leading flanks which are located towards the second end portion 16 of the toothed bar 13 enclose an angle alpha < 90° with the longitudinal axis 11 of the toothed bar 13 while the trailing flanks which are located towards the first end portion 15 of the toothed bar 13 enclose an angle beta = 90° with the longitudinal axis 11 of the toothed bar 13. This configuration of the flanks of to the serrations 22 and of the teeth 25 permit a relative displacement of the first and second lever 2;3 towards each other without the need of disengaging the locking mechanism 12.

In fig. 3 illustrates a device for soft tissue spreading comprising one embodiment of the pair of tongs 1 , a set of soft tissue retracting blades 18 (drawing shows only blades for one lever) and a set of trocars 19. The set of soft tissue retracting blades 18 essentially comprises blades 18 with different blade lengths I each being provided with second attachment means forming e.g. as a snap-fit together with the corresponding attachment means 17 at the free ends 8;9 of the first and second lever (fig. 1). The soft tissue retracting blades 17 each comprise a flared flange 37 at their free ends 42, said flared flange 37 permitting a self-fixation of the retracting blades 17 in the soft tissue. The retracting blades 17 have a contour of a circular arc when viewed parallel to the swivelling axis 6 of the swivel joint 10 of the pair of tongs 1 , whereby the central angle of the circular arc is smaller than 180° such that the retracting blades 17 form an oval when tightly pressed against each other. For insertion of the device a trocar 19 is selected from a set of trocars with different lengths and inserted between the retracting blades 17. After insertion of the retracting blades 17 into the soft tissue the pair of tongs 1 is spreaded and the trocar 19 removed. The tip 38 of the trocar 19 is cone like such that the retracting blades 17 abut the rear end 39 of the tip 38 such allowing the soft tissue to be protected against injuries through the retracting blades 17 during insertion of the device.

Fig. 4 illustrates an embodiment of the pair of tongs 1 which differs from the embodiment shown in fig. 1 only therein that the release member 14 is disposed in a separate casing 40 which is connected to the second lever 3. Such the toothed bar 13 does not penetrate the second lever 3. Furthermore, the locking mechanism 12 is provided with a retention means 20 (fig. 5) which permits to keep said release member 14 in a position where the locking mechanism 12 is disengaged.

As shown in fig. 5 the retention means 20 comprises a first and a second transverse opening 24';24" which are orthogonally arranged whereby the first transverse opening 24' is coaxial to the first transverse axis 27 of the release member 14 while the second transverse opening 24" is coaxial to the second transverse axis 26 of the release member 14. The first transverse opening 24' is provided with serrations 22 apt to engage the teeth 25 of the toothed bar 13 while the second transverse opening 24" is circular cylindrical. Furthermore, two diametrally located apertures 41 are provided, each having a cross section of a quadrant viewed parallel to the swivelling axis 6 (fig. 1). The apertures 41 and the first and second transverse openings 24';24" overlap each other such that a) two halves of the first transverse opening 24' are cut away, said halves being on opposite sides of the first transverse axis 27, and b) two halves of the second transverse opening 24" are cut away, said halves being on opposite sides of the second transverse axis 26.

By means of the so configured apertures 41 the release member 14 is rotatable about an axis parallel to the swivelling axis 6 (fig. 1) such allowing a reversible permanent disengagement of the locking mechanism 12 in a position of the release member 14 (as shown in fig. 5) and a rotation of the release member 14 in the direction as indicated by arrow Z until the serrations 22 in the first transverse opening 24' engage the teeth 25 of the toothed bar 13.

Claims

What is claimed is:

1. A pair of tongs (1 ) apt for soft tissue spreading and comprising

A) a first lever (2) and a second lever (3) being joined in a mutually rotatable manner by means of a swivel joint (10);

B) a reversibly engageable locking mechanism (12) by means of which said first and second lever (1 ;2) are reversibly fastenable in a desired mutual position; whereby

C) said first and second lever (1;2) include a handle portion (4;5) each by means of which said pair of tongs (1) may be grasped by one hand;

D) said locking mechanism (12) includes a release member (14) by means of which said locking mechanism (12) is disengageable and which is disposed at one of said first and second levers (2;3) between the respective handle portion (4;5) and said swivel joint (10); and

E) a resilient member (7) apt to spread said first and second lever (1 ;2) when said locking mechanism (12) is in a disengaged position.

2. The pair of tongs (1) according to claim 1 , wherein said locking mechanism (12) is provided with a retention means (20) permitting to reversibly keep said release member (14) in a position where said locking mechanism (12) is permanently disengaged.

3. The pair of tongs (1 ) according to claim 1 or 2, wherein said first and second lever (1 ;2) comprise a free end (8;9) each being located oppositely to the handle portion (4;5) of the respective lever (1 ;2) and each being provided with attachment means (17) by means of which soft tissue retracting blades (18) are attachable to said free ends (8;9).

4. The pair of tongs (1 ) according to claim 3, wherein said attachment means (17) comprise a detent portion configured to form a releasable fixation to a soft tissue retracting blade (18).

5. The pair of tongs (1) according to one of the claims 1 to 4, wherein said locking mechanism (12) comprises a toothed bar (13) having a longitudinal axis (11), whereby a first end portion (15) of said toothed bar (13) is hingedly connected to one of said first and second levers (2;3) while a second end portion (16) of said toothed bar (13) is connected to the release member (14) in such way that the toothed bar (13) may slide parallel to its longitudinal axis (11) within the release member (14) when the locking mechanism (12) is in its disengaged position.

6. An assembly for spreading soft tissue comprising a pair of tongs (1 ) according to one of the claims 1 to 5 and further comprising a set of soft tissue retracting blades (18).

7. The assembly according to claim 6, wherein said set of soft tissue retracting blades (18) comprises M > 2 pairs of soft tissue retracting blades (18) each pair having a different length.

8. The assembly according to claim 6 or 7, wherein the assembly comprises a set of trocars (19) each trocar (19) being insertable between blades of a corresponding pair of soft tissue retracting blades (17).

9. A method for spreading soft tissue comprising the steps of:

A) Performing a stab incision at the body of a patient;

B) Selecting a pair of soft tissue retraction blades (18) being appropriate to the soft tissue and the surgical procedure to be performed;

C) Attaching the pair of soft tissue retraction blades (18) selected under step B) to a pair of tongs (1 );

D) Selecting a trocar (19) being appropriate to the pair of soft tissue retraction blades (18) being selected under step B);

E) Inserting the pair of soft tissue retraction blades (18) together with the trocar (19) into the stab incision by means of the pair of tongs (1) until the desired insertion depth is reached; and

F) Spreading the pair of soft tissue retraction blades (18) and subsequently removing of the trocar (19).

10. The method according to claim 10, further comprising the steps of

G) inserting a bone screw through the opening formed between the soft tissue retraction blades (18);

H) tightening the bone screw in the bone; and

I) remove the pair of soft tissue retraction blades (18) from the stab incision by means of the pair of tongs (1 ).