WO2015164342A1

WO2015164342A1 - Torsional insertion system

Info

Publication number: WO2015164342A1
Application number: PCT/US2015/026826
Authority: WO
Inventors: Rick LUNN; Timothy Young; Wei Li Fan
Original assignee: Smith and Nephew Inc
Current assignee: Smith and Nephew Inc
Priority date: 2014-04-21
Filing date: 2015-04-21
Publication date: 2015-10-29
Anticipated expiration: 2016-10-21

Abstract

A surgical anchor insertion device provides for soft tissue repair employing a guide and an inserter mating via a controlled insertion region, such as a threaded engagement, in contrast to purely axial impact based approaches. A predetermined shaft length based on the anchor size and desired depth of insertion ensures that the threads engage for driving the anchor and that the depth of insertion is limited by the handle contacting the guide. A surgeon or operator disposes the guide against the insertion surface for fixing the guide and regulating insertion force such that the guide neither "backs out" nor over inserts the anchor. The handle employs a controlled engagement region such as a threaded mating for engaging an insertion shaft with the guide in a depth controlled manner to precisely vary the insertion depth based on rotation of the handle.

Description

TORSIONAL INSERTION SYSTEM

BACKGROUND

Modern surgical techniques often secure skeletal members such as bone, tissue, ligaments, and cartilage to other skeletal members or surgical appliances. It is often desirable to provide attachment to a bone or cartilage structure, based on the inherent rigidity of these skeletal members. Due to the sheer surface of most skeletal structures, drilled holes facilitate attachment. The drilled holes are occupied by a surgical anchor that is frictionally or threadedly engaged for providing a secure attachment point for connective elements such as tendons, ligaments and prosthetic appliances. Surgical anchors may therefore be subject to substantial and varying forces, primarily while being inserted due to transmission of loads through the insertion instruments used for delivery.

SUMMARY

A surgical anchor insertion device provided for soft tissue repair employing a guide and an inserter mating via a controlled insertion region, such as a threaded engagement, in contrast to purely impact based approaches. A predetermined shaft length based on the anchor size and desired depth of insertion ensures that the threads engage for driving the anchor and that the depth of insertion is limited by the handle contacting the guide. A surgeon or operator securely disposes the tip of the guide against the insertion surface for fixing the guide and regulating insertion force such that the guide neither "backs out" nor over inserts the anchor. Surgeons use a variety of anchors to conduct soft tissue repair. The problem with conventional approaches of securing these anchors is that loads imposed during insertion are extremely variable, and the method of insertion leaves room for a wide variety of user error, as well as high stresses and loading conditions associated with such anchors, due to, for example, dense bone or a difficult surgical environment. These conventional approaches can result in undesired results such as damage to the surrounding bone and anatomy, damage to the anchor or suture, and failure to insert the anchor.

Conventional approaches to surgical anchor insertion suffer from the shortcoming that the impact methods often employed do not provide sufficient control over the insertion mechanics, as typically a hammer blow is employed with somewhat variable results. Unfortunately, such conventional approaches suffer from the shortcomings that high impulse forces are applied to the inserter for anchor insertion, often resulting in increased difficulty of insertion, increased risk of damage to surrounding anatomic environment, and misalignment and breakage of anchors due to erratically directed forces. Accordingly, configurations herein employ a controlled engagement region such as a threaded mating for engaging an insertion shaft with the guide in a depth controlled manner to precisely vary the insertion depth based on rotation of the handle.

The disclosed approach provides an insertion system including an inserter, guide, and anchor responsive to insertion driven by axial and threaded mechanisms, or a combination of rotational and impact approaches, for achieving precise insertion without excessive axial or rotational forces resulting in anchor failure.

In further detail, configurations herein depict a surgical anchor insertion device, including an inserter having a handle and an insertion shaft extending from a distal end of the handle, in which the handle is responsive to rotational forces, a guide having a bore therethrough sized to receive the insertion shaft, and a controlled engagement region on the insertion shaft adjacent to the handle for engaging with the guide in a depth controlled manner. In the example arrangement, the controlled insertion region is defined by a threaded engagement between the handle and the guide responsive to rotation of the handle for providing incremental insertion and avoiding sudden and forceful movement of conventional hammer driven approaches.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of the invention will be apparent from the following description of particular embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention.

Fig. 1 is a perspective view of the surgical anchor insertion device as disclosed herein;

Fig. 2 is a side cutaway view of the insertion device of Fig. 1 ;

Figs. 3A and 3B show surgical anchor deployment using the device of Fig. 2; Fig. 4 shows a drill stop for establishing a predetermined depth in the installation of Figs. 3 A and 3B;

Figs. 5A-5E show an insertion sequence using the device of Figs. 3A and 3B; Figs. 6A-6C show the guide of Figs. 3A and 3B used for establishing the predetermined depth of Fig. 4; and

Fig. 7 shows an alternate course thread configuration of the threaded region of Figs. 3A and 3B.

DETAILED DESCRIPTION

Particular configurations of the disclosed surgical anchor insertion device are presented below and in the accompanying Figures. The disclosed insertion system employs modified guide/inserter using a guide tapped with internal threads as to mate with a threaded inserter. These two devices mate circumferentially with each other, creating linear motion along the axial direction of the shaft. This axial motion by circumferential rotation is used to insert the anchor in a controlled manner.

Conventional approaches to improve reliability in the surgical anchor insertion process have included tightening the tolerance between the guides and inserters, and adjusting the tolerances between anchors and bone holes to obtain the desired interference which results in the best chance of insertion with adequate fixation. Insertion forces directly relate to fixation force, and fixation force is a largely a measure of what constitutes a successful anchor. This helps to keep the direction of force all in-line, making for a greater likelihood of successful insertion. Unfortunately, conventional approaches to anchor insertion suffer from the shortcoming of imprecision in applying these insertion forces, as typically a hammer is employed and the blunt impact of a hammer blow can easily be excessive or misdirected; in a surgical environment, even a slight misdirection of "off-center" blow can have detrimental effects on anchor insertion. In addition, any angular shift in the guide in between the surgical steps of drilling the bone hole through the guide, and inserting the anchor through the guide, could misalign the anchor trajectory with the hole trajectory, imposing undesired and misaligned forces to the insertion system. Accordingly, configurations herein substantially overcome the above described shortcomings by providing a insertion handle and guide with a controlled engagement region, such as a threaded engagement between the handle and guides, that allows precise depth travel for inserting the anchor.

Fig. 1 is a perspective view of the surgical anchor insertion device as disclosed herein. Referring to Fig. 1, a surgical insertion device 100 includes a guide handle 110 having a bore 112 therethrough, and an insertion shaft 121 extending from a handle 140 through a cannulated shaft 120 and responsive to rotational 124 and impact 122, or axial, forces exerted on the handle 140. In the example configuration, the insertion shaft 121 has a controlled engagement region such as a threaded portion 118 for engaging a threaded portion 116 of the guide handle 110. The guide handle 110 includes a receptacle 114, which extends into the bore 112 and has a diameter defining the threaded portion 116. Rotational insertion force can therefore be generated from rotation of the handle 140 such that the threaded portion 118 of the insertion shaft 121 engages the threaded portion 116 of the guide handle 110 and generates axial force 122 when the guide handle 110 is held against a surgical surface such as a bone. The above-described process can be accomplished according to several different methods. For a particular approach, the inserter 140 will have a threaded portion 118 which mates with a tapped guide defined by the threaded portion 116. When the inserter 140 is screwed into the guide handle 110, it drives the anchor 132 (Fig. 2, below) into a drilled hole without the need for impact forces from a hammer. In this scenario, the guide handle 110 should be firmly held or affixed against the bone or other surgical surface by the surgeon.

Fig. 2 is a side cutaway view of the insertion device of Fig. 1. In operation, the insertion shaft 121 includes an interface tip 130 for engaging a bone anchor 132 The cannulated shaft 120 extends from the guide handle 110 for slidable and rotational communication with the insertion shaft 121 passing through the bore 112. The cannulated shaft 120 may have a set of prongs 126 on a distal end 128 of the cannulated shaft 120, such that the prong 126 is adapted for engaging a surgical surface for insertion of the bone anchor 132. The cannulated shaft 120 therefore extends the bore 112 through the guide handle 110, and the insertion shaft 121 extends from the handle 110 in a rigid coupling for transmitting axial, impact and rotations forces to the insertion shaft 121 running through the cannulated shaft 120. The handle 110 is therefore responsive to rotational and impact forces, and the insertion shaft 121 extending from the handle 110 is responsive to rotation from the handle for engaging the guide handle 110 and incrementally disposing the insertion shaft 121 through the guide handle 110.

In the approach of Fig. 2, the receptacle 114 on the guide handle 110 is responsive to the controlled engagement region defined by the threaded portion 118, such that the receptacle 114 defines a proximate end 113 of the bore 112 adapted to receive the insertion shaft 121. The depth controlled manner provided by the threaded portion therefore allows incremental travel based on rotation of the handle 140. The threaded portion 118 on the shaft 121 and the threaded portion 116 receptacle 112 have a thread pitch adapted for incremental depth travel proportional to rotation of the handle 140 and insertion shaft 121. Depending on the thread depth, each rotation of the handle 140 draws the insertion shaft axially 122 one thread width. In the example of Fig. 2, the controlled engagement region is a threaded portion 118 disposed on the insertion shaft adjacent to the handle. The

corresponding receptacle 114 is defined by the threaded portion 116 of the bore 112 at the proximate end 113 for engagement with the threaded portion 118 on the insertion shaft 121. Alternate approaches to the controlled engagement portion may be provided. For example, a rubber or resilient material may be provided such that the controlled engagement region includes a resilient region adapted to provide frictional force for controlling insertion. Resistance, tension and/or deformation of the controlled engagement region would provide frictional limitation to sudden forces and mitigate impact type anomalies in the insertion process.

Figs. 3A and 3B show surgical anchor deployment using the device of Fig. 2. Referring to Figs. 2, 3A and 3B, Fig. 3A shows a pre-insertion stage, and Fig. 3B depicts full insertion after deployment via the threaded regions 116, 118. In Fig. 3A, a surgical tunnel 160 has been previously drilled to a predetermined depth 162. The surgical tunnel 160 may have a tapered or narrowed region 160' at its terminus (bottom) sized for the anchor 132, or it may be uniform. A length 164 of the insertion shaft 121 defines an extent of anchor movement into the surgical tunnel 160; this distance less the length 166 of the guide handle 110 and the cannulated shaft 120 (extending from the guide handle 110) determines the insertion depth 162 of the anchor 132, once the handle 140 is drawn adjacent to the guide handle 110 from full engagement of the threaded regions 116, 118. By selecting the guide handle 110 / cannulated shaft 120 length 166 and insertion shaft 121 length 164 accordingly to correspond to the drilled predetermined depth 162, a precise insertion depth 162 into the insertion surface 150 is achieved.

Fig. 3B illustrates the insertion shaft 121 fully deploying the anchor 132 in the surgical tunnel 160 as rotation 124 applied to the handle 140 fully engages the threaded region 118 on the shaft 121 within the threaded region 116 of the receptacle 114 such that the distal end 119 of the handle 140 is drawn flush with the proximal end 114 of the guide handle 110. It may be further noted that the prongs 126 engage only with the surface of the bone, and may slightly embed themselves in the surface of the bone to provide sufficient grip while drilling the bone tunnel or inserting the anchor. The prongs 126 engage the insertion surface 150 as the fully engaged threaded regions 116, 118 dispose the anchor 132 flush with the surface 150.

In operation, the insertion shaft 121 has an engaging tip 130 for mating with a surgical anchor 132, such that the insertion shaft 121 is adapted to dispose a surgical anchor 132 to a predetermined depth 162 based on a length 164 of the insertion shaft and a length 166 of the bore through the guide handle 110. The guide handle 110 has a cannulated shaft 120 extending the bore 112 from a distal end 111 of the guide handle 110 opposed from the handle 140. In other words, the insertion depth 164 from the handle 140 is defined by the length of the insertion shaft 121 that exceeds the guide handle 110 and the cannulated shaft 120 as the handle 140 is drawn flush with the proximate end 113 of the guide. Generally, the guide handle 110 and cannulated shaft 120 are in a fixed arrangement, as are the handle 140 and insertion shaft 121, and the insertion shaft 121 slideably engages the bore 112 extending through the guide handle 110 and cannulated shaft 120.

The cannulated shaft 120 may also have a set of prongs 126 at a distal end

128, typically in a symmetrical arrangement but as few as 1 may suffice. The prongs would most commonly engage the flush insertion surface 150 but an alternative technique could encompass the prongs 126 extending to a shoulder defined by a tapered portion 160' of a surgical tunnel 160.

Fig. 4 shows a drill stop for establishing a predetermined depth 162 in the installation of Figs. 3A and 3B. Referring to Figs. 2, 3A and 4, the predetermined depth 162 is typically established by a drill bit 123 having a drill tip 123', which has a hard stop 125 is disposed at a location based on the depth 162. The same guide handle 110 is also employed with the drill bit 123 as with the insertion shaft 121, and the hard stop 125 placed such that the length of the drill bit that extends through the guide handle 110 (length 166 of guide) will define the predetermined depth 162.

Figs. 5A-5E show an insertion sequence using the device of Figs. 3A and 3B. Referring to Figs. 3A-3B, 4 and 5A-5D, In Fig. 5A the guide handle 110 and attached cannulated shaft 120 define the length 166 from the guide handle 110 to the insertion surface 150 upon full deployment. The cannulated shaft 120 is held against the surgical surface 150 by the guide handle 110, optionally aided by the prongs 126. In Fig. 5B, the drill bit 123 guided by the guide handle 110 and cannulated shaft 120 drills a hole 160 in the surgical surface 150, typically bone or hard tissue. A surgeon drills the tunnel 160 through the guide until the drill stop 125 bottoms out on the proximate end 113 of the guide handle 110. Alternative embodiments of defining insertion depth may be aligning markings on the guide and inserter devices. The drill stop 125 prevents the drill bit 123 from drilling beyond the intended depth 162 when it engages the proximate end 113 of the bore 112 on the guide handle 110. In Fig. 5C, the drill bit 123 is removed, and in Fig. 5D the engaged handle 140 drives the anchor 132 into the surgical tunnel 160 defined by the depth 162 of the drill hole of Fig. 5B. This is done by inserting the anchor 132 until the distal end of the handle 140 bottoms out on the proximate end 113 of the guide handle 110, setting the anchor 132 at the desired depth in the bore/tunnel 160. This depth 162 is predetermined by the relative working lengths of the guide handle 110/cannulated shaft 120 assembly and the insertion shaft 121 extending from the handle 140. A countersunk depth 150' may he achieved if the inserter working length 164' including the interface tip 130 so allows. There may be a small gap between the distal end of the anchor and the tunnel 160 such that the anchor 132 does not bottom out and for dimensional tolerance.

Figs. 6A-6C show the guide of Figs. 3A and 3B used for establishing the predetermined depth of Fig. 4. Referring to Figs. 2, 4 and 6A-6C, a drill 190 locks the drill bit 123 for rotation in the cannulation defined by the bore 112.

Fig. 7 shows an alternate course thread configuration of the threaded region of Figs. 3A and 3B. In an alternate approach, the insertion shaft 121 may have a more course mating thread 118' on the threaded portion 118 which mates with the threaded portion 116' of the guide. A smaller number of threads per inch (TPI) allows the insertion shaft 140 to be inserted via an impact force via a hammer 192, but still exert at least some control over the insertion rate due to the threaded rotation. Also, some surgical anchors 132 may employ angled threads, rather than parallel, transverse ribs. Selection of an insertion thread angle 180 to match an anchor thread angle 182 may allow the insertion shaft 121 and anchor 132 to rotate similarly for providing the same axial movement. The threaded portion 118' and the receptacle 116' may therefore have a steep thread pitch 180 adapted for rotation of the insertion shaft in response to impact forces on the handle 140 from a hammer 192. The insertion shaft 121 remains rigidly coupled to the handle 140 for transmission of both the rotational and impact force.

The insertion system may therefore be responsive to a thread angle 182 on the anchor 132, such that steeper thread angles are responsive to axial insertion and shallower thread angles are responsive to rotational insertion. Further the interface tip 130 may be adapted for at least one of rotational and axial insertion based on axial force 122 or rotational force 124.

An alternate arrangement may also provide for a gear system in the handle and inserter, or combination of both, for augmenting the rotational force of the insertion shaft based on handle rotation.

While the methods and apparatus defined herein have been particularly shown and described with references to embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.

Claims

CLAIMS What is claimed is:

1. A surgical anchor insertion device, comprising:

an inserter having a handle and an insertion shaft extending from a distal end of the handle, the handle responsive to rotational forces;

a guide having a bore therethrough, the bore sized to receive the insertion shaft; and

a controlled engagement region on the insertion shaft adjacent to the handle for engaging with the guide in a depth controlled manner.

2. The device of claim 1 further comprising a receptacle on the guide responsive to the controlled engagement region, the receptacle defining a proximate end of the bore adapted to receive the insertion shaft.

3. The device of claim 1 wherein the depth controlled manner provides incremental travel based on rotation of the handle.

4. The device of claim 2 wherein the controlled engagement region is a threaded portion disposed on the insertion shaft adjacent to the handle.

5. The device of claim 4 wherein the receptacle is a threaded portion of the bore at the proximate end for engagement with the threaded portion on the insertion shaft.

6. The device of claim 1 wherein the insertion shaft has an engaging tip for mating with a surgical anchor, the insertion shaft adapted to dispose a surgical anchor to a predetermined depth based on a length of the insertion shaft and a length of the bore through the guide.

7. The device of claim 6 wherein the guide has a cannulated shaft extending the bore from a distal end of the guide opposed from the handle.

8. The device of claim 7 wherein the cannulated shaft has a set or prongs at a distal end for fixation at a surgical insertion site corresponding to the surgical anchor.

9. The device of claim 5 wherein the threaded portion and the receptacle have a thread pitch adapted for incremental depth travel proportional to rotation of the handle and insertion shaft.

10. The device of claim 5 wherein the threaded portion and the receptacle have a steep thread pitch adapted for rotation of the insertion shaft in response to impact forces on the handle.

11. The device of claim 1 wherein the controlled engagement region includes a resilient region adapted to provide frictional force for controlling insertion.

12. The device of claim 10 wherein the insertion shaft rigidly coupled to the handle for transmission of rotational and impact force.

13. The device of claim 4 further comprising a gear system in the handle for augmenting the rotational force of the insertion shaft based on handle rotation.

14. A method of inserting a surgical anchor, comprising:

disposing an inserter having a handle and an insertion shaft extending from a distal end of the handle through a guide having a bore, the bore sized to receive the insertion shaft; and the handle responsive to rotational forces;

rotating the handle for engaging a controlled engagement region on the insertion shaft adjacent to the handle with a corresponding receptacle defined by a threaded portion on the guide for advancing the insertion shaft in a depth controlled manner.

15. The method of claim 14 wherein the receptacle on the guide is responsive to the controlled engagement region, the receptacle defining a proximate end of the bore adapted to receive the insertion shaft, wherein rotating for the depth controlled manner provides incremental travel based on rotation of the handle.

16. The method of claim 15 wherein the insertion shaft has an engaging tip for mating with a surgical anchor, further comprising inserting the insertion shaft to dispose a surgical anchor to a predetermined depth based on a length of the insertion shaft and a length of the bore through the guide.

17. A surgical insertion device comprising:

a guide having a bore therethrough;

a handle responsive to rotational and impact forces;

an insertion shaft extending from the handle and responsive to rotation from the handle for engaging the guide and incrementally disposing the insertion shaft through the guide; and

an interface tip for engaging a bone anchor, the guide defining a length of the bore based on a desired insertion depth of the bone anchor.

18. The device of claim 17 further comprising at least one prong on a distal end of the guide, the prong adapted for engaging a surgical surface for insertion of the bone anchor.

19. The device of claim 18 wherein the interface tip engages the bone anchor responsive to a thread angle on the anchor, such that steeper thread angles are responsive to axial insertion and shallower thread angles are responsive to rotational insertion.

20. The device of claim 19 wherein the interface tip is adapted for at least one of rotational and axial insertion.