Interspinous implants and methods for implanting same

(54) Title: SPINAL IMPLANT, IMPLANT OF (57) Summary:

INTERESPINAL PROCESS FOR PLACING IN AN INTERESPINAL PROCESS SPACE BETWEEN SPINAL PROCESSES OF SYMPTOMATIC DISC LEVELS AND UNILATERAL PLACEMENT METHOD OF AN IMPLANT (30) Unionist Priority: 01/05/2007 us 11 / 743,086,

7/16/2007 US 60 / 959,799, 7/24/2007 US 60 / 961,780, 10/29/2007

US 61 / 000,831,01 / 11/2007 US 61 / 001,430 (73) Holder (s): spinal simplicity llc (72) Inventor (s): harold hess (74) Attorney (s): DAVID DO NASCIMENTO

ADVOGADOS ASSOCIADOS (86) International Request: pct US08001231 de3o / hi / 2oos (87) International Publication: wo 2oos / i36877de

13/11/2008

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1/32 stenosis.

SPINAL IMPLANT, INTER-SPINAL PROCESS IMPLANT FOR PLACING IN AN INTER-SPINAL PROCESS SPACE BETWEEN SPINAL PROCESSES OF SYMPTOMATIC DISC LEVELS AND UNILATERAL PLACEMENT METHOD OF AN IMPLANT

BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION

The present invention relates to spinal implants and, more particularly, to an interspinal implant with foldable flaps for the treatment of lumbar spinal stenosis, to methods for percutaneous implantation of the interspinal implant and to techniques for determining the appropriate size of the interspinal implant.

DESCRIPTION OF THE RELATED TECHNIQUE

The backbone consists of a column of twenty-four vertebrae that extend from the skull to the hips. The soft tissue discs are arranged between adjacent vertebrae. The vertebrae provide support for the head and body, with the discs acting as shock absorbers. In addition, the backbone includes and protects the spinal cord, which is surrounded by a bony canal called the spinal canal. There is usually a space between the spinal cord and the boundaries of the spinal canal, so that the spinal cord and the nerves associated with it are not compressed.

Over time, the ligaments and bones that surround the spinal canal may thicken and harden, resulting in narrowing of the spinal canal and spinal compression of the spinal cord. This condition is called spinal stenosis, which results in pain and tingling in the back and feet, weakness and / or loss of balance. These symptoms often increase after walking or standing for a period of time.

There are a number of non-surgical treatments from These include non-steroidal anti-inflammatory drugs to reduce swelling and pain and injections of corticosteroids to reduce swelling and treat acute pain. Although some patients may experience relief from the symptoms of spinal stenosis with such treatments, many do not and therefore turn to surgical treatment. The most common surgical procedure for the treatment of spinal stenosis is decompressive laminectomy, which involves removing parts of the vertebrae. The purpose of the procedure is to relieve pressure on the spinal cord and nerves, increasing the area of ​​the spinal canal.

Decompression of the interspinal process (IPD) is a less invasive surgical procedure for the treatment of spinal stenosis. With EPD surgery, there is no bone or soft tissue removal. Instead, an implant or spacer is positioned behind the spinal cord between the spinal process that protrudes from the vertebrae in the lower back. A well-known implant used to perform IPD surgery is the X-STOP® device, which was first introduced by St. Francis Medical Technologies, Inc. of Alameda, CA. However, implantation of the X-STOP® device still requires an incision to access the spinal column to implant the XSTOP® device.

It would be advantageous to provide an implant to perform IPD procedures that can be percutaneously introduced into the interspinal space and effectively treat lumbar spinal stenosis.

BRIEF DESCRIPTION OF THE INVENTION

The present invention relates to a spinal implant used mainly to decompress the process for interspin procedures that can be percutaneously introduced into the interspin space. In its most basic configuration, the device includes a portion of the

3/32 body having an internal cavity, a plurality of locking tabs adapted and configured to move between a retracted packaged position within the internal cavity of the body portion and an extended implant position of the internal cavity of the body portion and a device for moving the plurality of locking tabs from the packaged position to the implant position.

The present invention also relates to a method of percutaneous placement of a spinal implant during an inter-spinal decompression procedure, which includes, among others, the steps of providing a spinal implant that has a body portion that contains a plurality of folding locking tabs that are sized and configured for symptomatic spines of adjacent vertebrae, advancing a curved stylus through the skin on one side of the backbone downward in the spinal processes between the levels of the symptomatic disc, directing the spinal implant along the path defined by the curved stylus in the spinal processes from a unilateral approach and subsequently implanting of the locking tabs to couple the spinal processes of the adjacent vertebrae.

couple processes to disk levels

The present invention further relates to a method of percutaneous placement of a spinal implant, which includes the steps of providing a spinal implant that has a portion of the body that contains a plurality of folding locking tabs sized and configured to couple the spinal processes of the adjacent vertebrae at symptomatic disc levels, advancing a curved stylus through the skin on one side of the backbone, down in the spinal process between the levels of the symptomatic disc and out through the skin on the opposite side of the backbone, to

4/32 allow a bilateral approach to the spinal process. The method additionally includes the steps of directing the spinal implant along the path defined by the curved stylus in the spinal processes on either side of the backbone and subsequent implantation of the locking flaps to couple the spinal processes of the adjacent vertebrae. The implant can be advantageously used for various treatments including as an aid to a fusion, for the treatment of back pain and as a treatment to relieve the symptoms of a protruding lumbar disc.

The present invention additionally relates to a tool kit to facilitate percutaneous implantation of the device. The kit includes one or more of the following components: a stylus set that has a graduated positioning stylus, a curved stylus and an adjustable bridge portion with the curved guide sleeve for the curved stylus. The kit may additionally include a kit of curved tubular dilators of varying diameter and a plurality of implants of varying size.

The present invention also relates to an apparatus for more favorably measuring the size of an interspinal implant for the treatment of lumbar spinal stenosis. The apparatus includes a separation device sized and configured for percutaneous insertion into the interspin space between adjacent spinal processes, in which the separation device is mobile between a closed insertion position and an open distraction position. The apparatus additionally includes an implantation device for moving the separation device between the closed insertion position and the open retraction position, in which the amount of movement of the implantation device corresponds to a size of the interspinal implant more favorable for placement in the interspin space between spinal processes

5/32 adjentes.

The present invention also relates to a method for measuring the most favorable size of an interspinal implant for the treatment of lumbar spinal stenosis. The method includes the stage of percutaneous introduction of the distraction device into the interspin space between adjacent spinal processes, in which the separation device is mobile between a closed insertion position and an open distraction position. 0 The method additionally includes the step of moving the distraction device between the closed insertion position and the open retraction position and then the correlation of the movement of the distraction device with a more favorable size of the interspin implant for placement in the interspin space between the processes adjacent spines.

In one embodiment, the present technology refers to an interspinal implant for placement between the spinal processes of symptomatic disc levels including a wrap in which the top and bottom portions of the wrap define four internal grooves that end in openings in the wrap, being that the wrap has a retainer adjacent to each opening. Four locking tabs with folding tabs slide together in a respective groove between: i) a packed position where the tabs are inside the grooves; and ii) an implant position in which the flaps extend out of the wrap. Each flap has a set of tongue teeth to couple and lock the respective retainer in the implant position. A pair of coaxial locking wheels is pivotally mounted on the wrap to selectively exert a force against each locking tab to move the locking tabs from the packaged position to the implant position and an implantation cable for the wheels to cause their

6/32 rotation.

The implant may additionally have a guide on the wrap to accommodate a stylus during a percutaneous placement procedure. In addition, two flaps can be positioned on the first parallel geometric planes, spaced from each other that extend on a first side of a center line of the envelope, with two other flaps located on the second parallel planes spaced from each other that extend on a second side centerline of the wrap.

The interspinal implant can also include a placement tool to introduce the wrap into the spinal process. The placement tool may include an elongated tubular rod that has a rectilinear distal portion and a curved proximal portion that forms a central lumen to accommodate the implantation cable and a coupling sleeve on the rectilinear distal portion to selectively couple the wrap. In another embodiment, the placement tool can be an elongated tubular rod that is curved. The interspin implant can also include a set of stylets for percutaneous insertion of the interspin implant. The stylus set includes an elongated graduated positioning stylus to adjust a position of the stylus set on an axis of a backbone, a curved stylus to gain lateral access to an interspin space and an adjustable guide bridge that has a central portion which extends between the positioning stylus and the curved stylus to guide the positioning stylus, the bridge also having a curved guide sleeve to guide the curved stylus. The curved stylus can be dimensioned and configured for unilateral or bilateral insertion.

The interspinal implant can also include a drive mechanism that includes an elongated arched hollow cable fixation device that has a distal end

7/32 tapered with flexible pins extending inwardly radially that form a distal opening, an implant cable that has a distal end attached to the interspinal implant and a proximal end that has a sphere captured by the flexible pins and a second tube for the insertion in the cable fixing device to deflect the flexible pins and, in turn, release their sphere after implantation of the interspinal implant.

In another embodiment, the present technology relates to a method of placing a spinal implant that comprises the steps of: providing a spinal implant that has a portion of the body that contains a plurality of folding locking tabs sized and configured to couple the processes spinal column of adjacent vertebrae at symptomatic disc levels; advancement of a curved stylet through the skin on one side of the spine downwards in the spinal processes between the levels of the symptomatic disc; directing the spinal implant along a path defined by the curved stylus in the spinal processes from a unilateral approach; and implantation of the locking tabs to couple the spinal processes of the adjacent vertebrae.

However, in another embodiment, the present technology relates to a device for percutaneously measuring the most favorable size of an interspinal implant. The measuring device includes a proximal implant portion that includes a trigger tube containing a stem, a distal measuring set that includes four swivelly connected arms connected at four coupling junctions, a central axis connected to the proximal end stem of the drive tube and connected to the coupling joint at a distal end and two opposed concave bins adjacent to the opposite coupling joints

8/32 of the concave bins adapted to couple a backbone when the stem and, in turn, the central axis are pulled in a proximal direction while the drive tube remains stationary, so that the connected arms expand from a closed position to a measuring position. The measuring device may also include a strain gauge operatively associated with the drive tube and stem to determine one. force to be applied by an interspinal implant.

In another embodiment, the measuring device includes an elongated portion of the body that has a pair of jaw elements at a distal end of the same for positioning in the interspin space, a bin in each jaw element, the bins being adapted and configured to support an adjacent spinal process, a trigger tube and a stem partially housed within the trigger tube and joined to the jaw elements by selectively moving the jaw elements from a closed position to an open position where the bins couple the spinal process, in which a stem travel distance within the drive tube correlates with a length to which an interspin space has been divided.

The present technology also includes a method to measure the most favorable size of an interspin implant for the treatment of lumbar spinal stenosis including the steps of percutaneous introduction of a distraction device into the interspin space between adjacent spinal processes, in which the separation device is movable between a closed insertion position and an open distraction position, movement of the distraction device between the closed insertion position and the open retraction position and the correlation of the movement of the distraction device with a more favorable size of the interspinal implant for the

9/32 placement in the interspin space between adjacent spinal processes.

It should be understood that each aspect of the implants and the methods described can be intercalated and freely coupled with various other aspects to use any combination of them. These and other aspects of the interspinal implant and the percutaneous placement method of the present invention will become more readily apparent to elements skilled in the art from the following detailed description of the preferred embodiment taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the elements skilled in the art to which the present invention belongs will readily understand how to produce and use the interspinal implant of the present invention without improper experimentation, the preferred embodiments of it will be described in detail below with reference to certain figures, in which:

Figure 1 is a perspective view of an interspinal implant in accordance with the present invention, which includes a main wrap portion that has a plurality of locking tabs and an insertion tool to facilitate percutaneous introduction of the implant into the backbone;

<td>Figure 2 is</td><td>a view in</td><td>plant</td><td>higher</td><td>of</td>

<td>interspinal implant of</td><td>Figure 1, which</td><td>illustrates</td><td>the flaps</td><td>in</td>

<td>locking in one position</td><td>implant;</td><td></td><td></td><td></td>

<td>Figure 3 is</td><td>a view in</td><td>elevation</td><td>side</td><td>of</td>

interspinal implant of Figure 1;

Figure 4 is a cross-sectional view taken along line 4-4 of Figure 3 that illustrates a locking wheel disposed within the main envelope of the interspin implant to implant a pair of flaps.

10/32 locking opposite;

Figure 5A is a detailed perspective view of the lower portion of the main envelope of the interspinal implant of Figure 1;

Figure 5B is a plan view of the inside of the lower portion of the main wrapper of Figure 5A;

Figure 5C is a side view of the inside of the lower portion of the main wrapper of Figure 5A;

Figure 5D is a view of the proximal end of the lower portion of the main envelope of Figure 5A;

Figure 6A is a detailed perspective view of the upper portion of the main envelope of the interspinal implant of Figure 1;

Figure 6B is a plan view of the inside of the upper portion of the main wrapper of Figure 6A;

Figure 6C is a side view of the inside of the upper portion of the main wrapper of Figure 6A;

Figure 6D is another side view of the inside of the upper portion of the main envelope of Figure SA with the inside shown in broken lines;

Figure 6E is a view of the proximal end of the upper portion of the main envelope of Figure 6A;

Figure 6F is a view of the distal end of the upper portion of the main casing of Figure 6A;

Figure 7A is a detailed perspective view of a locking tab for the interspin implant of Figure 1;

<td>The figure</td><td>7B</td><td>is</td><td>an</td><td>View</td><td>side</td><td>gives</td><td>tab</td><td>in</td>

<td>Figure locking</td><td>7A;</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>The figure</td><td>7C</td><td>is</td><td>an</td><td>View</td><td>higher</td><td>gives</td><td>tab</td><td>in</td>

<td>Figure locking</td><td>7A;</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>The figure</td><td>7D</td><td>is</td><td>an</td><td>View</td><td>bottom</td><td>gives</td><td>tab</td><td>in</td>

locking of Figure 7A;

Figure 7E is an end view of the

11/32 locking of Figure 7A;

Figure 8A is a detailed perspective view of a locking wheel for the interspinal implant of Figure 1;

<td>The figure</td><td>8B is</td><td>a view</td><td>higher</td><td>gives</td><td>wheel</td><td>in</td>

<td>Figure locking</td><td>8A;</td><td></td><td></td><td></td><td></td><td></td>

<td>The figure</td><td>8C is</td><td>a view</td><td>side</td><td>gives</td><td>wheel</td><td>in</td>

<td>Figure locking</td><td>8A;</td><td></td><td></td><td></td><td></td><td></td>

Figure 8D is an end view of the locking wheel of Figure 8A;

Figure 8E is a detailed top view of another locking wheel and a portion of the drive mechanism for use in the interspinal implant of Figure 1;

Figure 9A is a detailed perspective view of a placement tool for use with the interspinal implant of Figure 1;

<td></td><td>THE</td><td>Figure</td><td>9B is</td><td>an</td><td>View</td><td>side</td><td>gives</td><td>tool</td><td>in</td>

<td>placing</td><td>gives</td><td>Figure</td><td>9A;</td><td></td><td></td><td></td><td></td><td></td><td></td>

<td></td><td>THE</td><td>Figure</td><td>9C is</td><td>an</td><td>View</td><td>higher</td><td>gives</td><td>tool</td><td>in</td>

<td>placing</td><td>gives</td><td>Figure</td><td>9A;</td><td></td><td></td><td></td><td></td><td></td><td></td>

<td></td><td>THE</td><td>Figure</td><td>9D ê</td><td>an</td><td>View</td><td colspan="3">distal end</td><td>gives</td>

placement tool of Figure 9A;

Figure 10A is a perspective view of the interspinal implant of the present invention, in cross section to illustrate the four locking tabs and two locking wheels in a packaged position;

Figure 10B is a perspective view of the interspin implant of the present invention, in cross section to illustrate the four locking tabs and two locking wheels in an implant position;

Figure 11 is a perspective view of the interspinal implant of the present invention, with the four locking tabs fully retracted and packaged within the device's casing;

12/32

Figure 12 is an elevation view of the set of stylets used to percutaneously implant the interspinal implant of the present invention;

Figures 13 to 16 illustrate the percutaneous introduction of the interspinal implant of the present invention by means of a unilateral approach on one side of the spine;

Figures 17 to 21 illustrate the percutaneous introduction of the interspinal implant of the present invention through a bilateral approach on either side of the backbone;

Figure 22 is a perspective view of a cable placement or drive device for use in conjunction with the interspinal implant of the present invention;

Figure 23 is a view of the distal end of the device of Figure 22;

Figure 24 is an illustration of an apparatus for measuring the most favorable size of an interspin implant, which is shown in an initial measurement position;

Figure 25 is an illustration of the apparatus shown in Figure 24 in an open or distracting position;

Figure 25 is an illustration of another device for measuring the most favorable size of an interspinal implant, which is shown in an insertion position or in a closed position;

Figure 27 is an illustration of the apparatus shown in Figure 26 in an open or distracting position; and Figure 28 is a top plan view of a tool kit to facilitate percutaneous placement of a spinal implant.

DETAILED DESCRIPTION OF THE PREFERRED ACHIEVEMENTS

The present invention overcomes many of the prior art problems associated with implants to relieve spinal stenosis. The advantages and other features of the

The system described in the present invention will become more readily apparent to elements skilled in the art from the following detailed description of certain preferred embodiments taken in conjunction with the drawings that determine representative embodiments of the present invention and in which similar numerical references identify similar structural elements . All descriptions relating to the present invention as horizontal, vertical, left, right, top and bottom are made with reference to the figures and are not intended to be limiting. For reference, proximal is usually the area or portion adjacent or close to the surgeon since distal refers to the remote or distant portion of the surgeon.

SPINAL IMPLANT

Referring now to Figure 1, an interspinal implant constructed in accordance with a preferred embodiment of the present invention and generally designated by reference number 10 is illustrated. The implant 10 is particularly well suited for use in performing minimally invasive surgical procedures for treating spinal stenosis, including, for example, decompression of the interspinal process (IPD).

It is envisaged, however, that the implant 10 of the present invention can also be used in other spinal procedures, including, but not limited to, as an aid in spinal fusion procedures. Those skilled in the art will readily appreciate from the following description that the interspinal implant of the present invention is well suited for percutaneous insertion and thereby overcome many of the deficiencies of prior art devices currently used in IPD procedures. That is, implant 10 is sized and configured for insertion and placement through a skin incision with

14/32 a small perforation.

Referring to Figures 1 to 4, the interspinal implant 10 of the present invention includes a portion of the main body or casing 12 which has the upper and lower casing portions 12a, 12b. The wrap portions 12a, 12b can have an interference fit or are secured by a fastener (not shown) inserted into a threaded hole 44. The wrapping portions 12a, 12b are preferably formed of a biocompatible polymeric material that has an elastic modulus that is substantially similar to that of bone, for example, polyether ether, thermoplastic ketone (PEEK) or a similar material. The main wrap 12 can also be made of a biocompatible metal such as a titanium alloy or similar material. The main envelope 12 is dimensioned and configured for placement between the spinal processes of symptomatic disc levels. (see also Figures 5A and 5B). Placing the implant in this way limits the extent to symptomatic levels, while preserving mobility and shelter. Although the wrapper 12 is generally in the form of a bullet or truncated cone, it is envisaged that the curved end section may be truncated or presented in a planed orientation, whereby the wrapper would assume a barrel-shaped configuration among many other variations. Wrap 12 has opposite depressions 13 which serve to match the profile of the adjacent bone when implanted.

The lower wrap portion 12b includes an optional guide 15 to accommodate a stylus during a percutaneous placement procedure, as best seen in Figures 5A-5D and described in further detail below. The guide 15 has a hole 17 that can slide over a stylus. Main wrapper 12 houses four locking tabs with

15/32 folding tabs 14a-14d adapted and configured to couple adjacent vertebral portions of the spinal process. The wrapper 12 has four openings 46a-46d that allow the locking tabs 14a-14d to extend out of the wrapper 12. The locking tabs 14a-14d are preferably formed of a lightweight, high strength biocompatible material such as , for example, titanium or a similar material.

During implantation of implant 10, the locking tabs 14a-14d are packaged within the implant wrapper 12 10, as best seen in Figures 1OA and 11, forming a lean structure. As best seen in Figures 4, 5A, 5B, 6A, 6B, 1OA and 10B, two curved guide rails 19 formed within the wrap portions 12a, 12b accommodate the flaps 14a-14d in the packaged position.

Each locking tab 14a-14d includes a set of tongue teeth 16, as best seen in Figures 7a-7c. The teeth of the tongue 16 on each flap 14a-14d are dimensioned and configured to couple a corresponding retainer structure 18 formed adjacent to the openings 46a-46d in the wrapper 12 during implantation, to lock the flaps 14a-14d in the desired position. The locking tabs 14a-14d secure the adjacent spinal processes. Although implant 10 is used primarily as a spacer between spinal processes, the selectively foldable flaps 14a-14d allow implant 10 to also be used to divide the spinal process. Advantageously, since the flaps 14a-14d are implanted to fix the spinal processes, the migration of the implant 10 is prevented.

As best seen in Figure 3, the two flaps 14c and 14b on the side of the implant 10 are located on parallel geometric planes separated from each other.

16/32 extend on the side of the horizontal centerline of the implant wrap 12. In other words, in an implanted position, the locking tab 14b resides on a deployment plane that is parallel to the deployment plane of the locking tab 14c. Similarly, the locking tab 14a resides on a plane that is parallel to the deployment plane of the locking tab 14d. It follows that locking tabs 14a and 14c reside in a common deployment plan and locking tabs 14b and 14d reside in a common deployment plan. This guidance helps to prevent device migration and maintain stability within the spinal process.

The movement or placement of the locking tabs 14a-14d is controlled or performed by a pair of coaxial locking wheels 20a and 20b, shown in Figures 4 and 8a8d. The locking wheels 20a and 20b have a central opening 25a and 25b, respectively, for mounting on a central hub 21 in the casing 12. The locking wheel 20a is housed in the upper wrap portion 12a to control the movement of the flaps 14a and 14c, the locking wheel 20b being housed in a portion of the lower wrap 12b to control the movement of the flaps 14b and 14d. More particularly, each of the opposite ends 23a, 23b of the locking wheels 20a, 20b is adapted and configured to exert a force against a bearing surface 22 formed at the end of each locking tab 14a-14d, which is best seen in the Figures 10A and 10B.

According to a preferred embodiment of the present invention, locking wheels 20a, 20b and locking tabs 14a-14d are controlled in this way by an implantation cable 27, shown in Figure 10B. One or more cables can be used. The implant cable 27 is fixed in a key-shaped opening 41 formed in the locking wheels 20a, 20b to facilitate remote activation of the

17/32 locking wheels 20a, 20b and the corresponding movement of the locking tabs with the tongue 14a, 14b. The cable 27 divides at the distal end and ends in two spheres (not shown). Each sphere can pass through the respective key-shaped openings 41 and be selectively captured in them. The cable 27 passes out of the wrap 12 through a passage 90 for use by the surgeon. Once deployed, cable 27 can be detached from the key-shaped opening 41 or cut as described below.

Alternatively, the key-shaped opening 41 may be located away from the pivot point of the locking wheels 20a, 20b to provide a greater mechanical advantage. The cable 27 can also form a loop by joining the two key-shaped openings 41. The loop can be a simple loop at the distal end of the cable 27 or a long loop that passes out of the envelope through passage 90. In addition, a second similar loop of the cable (not shown) can join two other key-shaped openings at the opposite ends of the locking wheels 20a, 20b to further increase the mechanical strength during implantation. The second loop of the cable also passes out of the implant 10 through a passage similar to the passage 90, but is formed at the distal end of the implant 10. Once implanted, the loop of the cable can be cut or left as part of the implant 10.

As best seen in Figures 1-3, 9a9d and 11, the interspinal implant 10 is associated with a placement tool 24 adapted and configured to facilitate percutaneous introduction of the implant 10. The placement tool 24 includes an elongated tubular nail 26 that it has a straight distal portion 26a and a curved proximal portion 26b. In another embodiment, the tubular rod 26 can be curved without a straight portion. The tubular stem 26 has a central lumen 29 to accommodate the proximal portion of the

18/32 implantation cable 27. At a distal end, the placement tool 24 has a coupling sleeve 28 to selectively couple a locking clamp 49 to a tail 10b of the wrapper 12. Gasket 28 has a slot 92 and the clamp 49 has one or more projections 94 that couple to form a torsion lock to selectively couple the laying tool 24 to the casing 12. The joint 28 can also form a cutting surface 51, as best seen in Figures 10A and 10B, against which the cable 27 can be distributed for cutting. As the joint 28 rotates, a projection 59 raises the cable 27 so that the cutting surface 51 can cut the cable 27 after the locking tabs 14a-14d have been implanted by the locking wheels 20a, 20b. When cable 27 is a long loop, one end is simply released while the other end of cable 27 is pulled to remove cable 27. It is also provided that each locking wheel 20a, 20b can have a loop or respective cable 27. However, in another embodiment, the cable 27 is relatively short and remains attached to the locking wheels 20a, 20b after implantation. To drive the locking wheels 20a, 20b, there is a longer secondary cable (not shown) that runs from the proximal end to the distal end of the placement tool 24 and is looped around the cable 27. The secondary cable then passes out of the proximal end of the placement tool 24. The ends of the secondary cable are pulled in order to pull the cable 27 and, in turn, drive the locking wheels 20a, 20b. Then, one end of the secondary cable is simply released, the other end being pulled out to remove the secondary cable.

Referring to Figure 8E, another embodiment of a locking wheel 20 'is shown. The locking wheel 20 'has spaced grooves located on the hub

19/32 central 21 'adapted and configured to couple complementary spaced teeth in a drive mechanism 27'. The central hub 21 'is relatively thicker near the central opening 25' so that the teeth on the conical head of the drive mechanism 27 'are effectively interspersed with the grooves to form a mechanism for moving the gear. Various other forms can also form an effective mechanism for moving the gear. The drive mechanism 27¹ it is preferably a stem extending along the long axis of the implant 10. The conical head of the drive device 27 'can be between the two locking wheels 20', or each locking wheel can have a respective drive mechanism 27 ' . At the other end (not shown), the drive mechanism 27 'ends near the end of the wrap 12 and forms a socket. A screwdriver-type device (not shown) introduces the placement tool 24 and attaches to the stem fitting. When rotating the screwdriver type device, the drive mechanism 27 'is rotated and, thus, one or both locking wheels 20' are rotated in the opposite direction to perform the implantation of the locking tabs 14a, 14b of the implant 10.

STYLES SET

Referring now to Figure 12, a set of stylets 30 adapted and configured to facilitate percutaneous insertion of the interspinal implant 10 is shown. The set of stylets 30 includes an elongated graduated positioning stylus 32 to adjust the position of the set 30 around the central axis of the patient's backbone. At a distal end, the graduated positioning stylus 32 has a pointed tip 31 adapted and configured to be introduced into the patient. At a proximal end, the positioning stylus

Graduated 20/32 32 has a button 3 7 to allow easier control of the stylus 32 by the surgeon. The stylus set 30 additionally includes a curved stylus 34 to gain lateral access to the interspin space and an adjustable guide bridge 36 which has a curved guide joint 36a for curved stylus 34. Adjustable guide bridge 36 also has a portion central 36b that acts as an insertion guide for the graduated positioning stylus 32. The curved stylus 34 has a distal end 33 adapted and configured to be introduced into the patient and a proximal end with a loop / path retainer 34a. The relationship between the loop / path retainer 34a and the curved guide joint 36a defines a maximum insertion depth for the curved stylus 34.

UNILATERAL PLACEMENT OF THE IMPLANT

Referring to Figure 13, in use, the graduated stylus 32 is advanced through a small percutaneous incision in the patient's back, under fluoroscopy, so that the pointed tip 31 reaches the interspin space. The distance (D) from the skin to the interspin space is then observed, based on the gradations in the stylus 32. Alternatively, the same distance can be measured from a preoperative CT scan. In each event, the central guide joint 36b of the adjustable guide bridge 36 is positioned on the stylus 32 and the distance (D) is marked in a perpendicular from the direction to the length of the backbone. This distance (D) corresponds to the adjusted length of the adjustable guide bridge 36 of the stylus set 30. Thereafter, the curved stylus 34 is advanced downwards in the interspin space through the curved guide joint 36a of the adjustable guide bridge 36. The curved stylus 34 has a radius of curvature equal to D so that, upon insertion, the distal end 33 moves adjacent to the pointed tip 31 of the graduated stylus 32 in the interspin space.

21/32

At this point in the advance of the curved stylus 34, the travel stop 34a at the end of the stylus 34 is adjacent to the guide gasket 36a to prevent further extension. As a result, the path retainer 34a is threadably removed or else from the end of the curved stylus 34 and the rest of the stylet set 30 including graduated stylus 32 are also removed. However, the curved stylus 34 remains in place, as shown in Figure 14. Then, as shown in Figures 14 and 15, the successive dilators 40, 42 are placed on the curved stylet 34, while observing the interspin space under fluoroscopy. The dilators 40, 42 can also have radii of curvature equal to D. The dilators 40, 42 serve to distract the interspin space. Although two dilators 40, 42 have been shown, more or less of them can be used to perform the desired distraction from the interspin space. Once the proper distraction of the interspinal space has been observed, implant 10 is introduced percutaneously through a lumen 43 formed in the last dilator 42. Preferably, dilators 40, 42 divide the spinal process and implant 10 maintains only division, although the implant 10 can also perform the division. Alternatively, the implant of the implant 10 can be performed by inserting the implant 10 over the curved stylet 34 as a guide in the interspin space through the guide hole 15 in the lower envelope portion 12b.

Implant 10 is maneuvered down into the interspin space. As shown in Figure 16, implant 10 has a button 39 selectively attached to the placement tool 24 to assist the physician in maneuvering the implant 10. Button 39 can include an extension that is inserted into the central lumen 29 to make the nail 26 more rigid. Once the implant 10 is in position, the dilator 42 can be removed by maintaining the implant 10 position for the implant

22/32 of the locking tabs 14a-14b.

ACTIVATION OF THE LOCKING TABS AFTER UNILATERAL INSERTION

Once the wrap 12 is sheltered between the spinal processes so that contact is made with the bone in the depressions 13, the locking tabs 14a-14d are implanted. The surgeon uses the cable 27 to implant the locking tabs 14a-14d and, in this way, to fix the implant position 10. The distal end 27a, 27b of the cable 27 is joined to the coaxial locking wheels 20a, 20b, respectively, so that, as the cable 27 is pulled proximally, the locking wheels 20a, 20b rotate on the central hub 21 in wrapper 12.

The opposing ends 23a, 23b of the locking wheels 20a, 20b are pushed against the bearing surfaces 22 of the respective locking tabs 14a-14d so that the locking tabs 14a-14d are pushed outward on the guide tracks 19 of wrap 12. As the tongue teeth 16 of the locking tabs 14a-14d move outwardly beside the frame of retainer 18 of wrapper 12, retainer 18 engages the corresponding tongue tooth 16 to prevent locking tabs 14a-14d move inward again in the wrapper 12. As a result of the external movement, the locking tabs 14a14d couple the spinal processes until the surgeon feels the adequate resistance, for example, the implantation. Once the locking tabs 14a-14d are deployed, the cable 27 is released or cut. The implant 10 then remains implanted between the spinal processes. In one embodiment, a tilt element or elements such as a spring extends between the locking wheels 20a, 20b so that their movement does not occur before or after implantation.

In one embodiment, to release cable 27, a second cable (not shown) extends below the tool

23/32 placement 24. The second cable is looped around the cable 27 and returns through the central lumen 29 of the placement tool 24. The surgeon can pull on the second cable to perform a pull on the cable 27. Once the tabs locking devices are implanted, the surgeon releases one end of the second cable loop and then pulls this second cable out of the placement tool 24, thereby leaving cable 27 with the implant in the patient.

BILATERAL PLACEMENT OF THE IMPLANT

With reference to Figures 17-21, the operating steps used in the bilateral placement of the interspin implant 10 of the present invention are illustrated. First, as shown in Figure 17, the central portion 36b of the adjustable guide bridge 36 is positioned over the graduated stylus 32 and the graduated stylus 32 is introduced to the depth of the patient's backbone. The measured distance (D) is used to dimension the adjustable guide bridge 36. A second curved stylus 34 ', similar to the curved stylus 34, but longer, is then advanced through the skin down into the interspin space through the curved joint 36a of the adjustable guide bridge 36. The curved stylus 34' is also extensible and the advancement of the curved stylus 34 'continues until the distal end 33 of the curved stylus 34' punctures the skin on the opposite side of the backbone.

As shown in Figures 18 and 19, the adjustable guide bridge 36 and graduated stylus 32 are removed. The successive tubular dilators 50, 52 are placed on the curved stylus 34 'when observing the interspin space under fluoroscopy. These dilators 50, 52, with successively larger diameters, lie along the same route as the curved stylus 34 'through the interspin space until the distal ends 53, 55 respectively, pass out of the patient's body.

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Once the proper division of the interspinal space is observed, the interspinal implant 10, with a profile slightly smaller than the diameter of the larger dilator 52 is introduced percutaneously through the lumen 57 of the last dilator 55. The surgeon guides the implant 10 downwards in the interspinal space, approaching one or the other or both sides of the backbone, as shown in Figure 20. Alternatively, once the interspin space has been properly divided by the dilators 50, 52, a guide stylus (not shown) can be inserted again after removing the last dilator 52. The implant 10 can then be inserted over the stylet guide in the interspin space.

ACTIVATION OF THE LOCKING TABS AFTER BILATERAL INSERTION

As best seen in Figure 20, to activate the locking tabs 14a-14d, the implant is introduced through the final dilator 52 using the placement tool 24a attached to the proximal tail 10b of the implant 10. When passing a second placement tool 24b on the dilator 52 in an opposite direction, the second placement tool 24b is joined to a distal tip 10a of the implant 10. Each placement tool 24a, 24b has a corresponding button 39a, 39a at the proximal end. The final dilator 52 is removed partially or completely when maintaining the position of the implant 10 with the placement tool 24a or with the tools 24a, 24b, depending on the circumstances.

When holding the implant 10 in position with the placement tools 24a, 24b, the implant cable (not shown) is pulled to drive the locking tabs 14a-14d of the implant 10. One distal end of the cable is attached to the locking wheels coaxials 20a, 20b so that while the cable is pulled, the locking wheels 20a, 20b rotate over the

25/32 central hub 21 in the wrapper 12. The opposite ends 23a, 23b of the locking wheels 20a, 20b are pushed against the bearing surfaces 22 of the respective locking tabs 14a-14d so that the locking tabs 14a-14d slide out on the guide tracks 19 of the wrap 12. As the tongue teeth 16 of the locking tabs 14a-14d move outwardly beside the wrap retainer frame 18, the retainer 18 engages the corresponding tongue tooth 16 to prevent the locking tabs 14a-14d from move inward again to wrap 12. As a result of the external movement, the locking tabs 14a-14d couple the spinal processes until the surgeon feels the adequate resistance, for example, the implantation, as shown in Figure 21.

Once the locking tabs 14a-14d are implanted, the cable is released and the placement tools 24a, 24b are detached from the tip 10a and tail 10b of the implant 10. The implant 10 then remains implanted between the spinal processes, as as shown in Figure 21. Before fully removing the placement tool 24a from the implant 10, the implant cable is cut. To cut the cable, the laying tool 24a rotates the cutting surface 51 and, in turn, the cable is cut when distributed against the cutting surface 51.

It is envisaged that the placement tools 24a, 24b are joined to the interspin implant 10 via a selective torsion lock, as noted above. Alternatively, the placement tools 24a, 24b can also be designed so that they have tapered ends with pins that join a bulbous portion of the tip 10a and tail 10b of the interspin implant 10. Similarly, an unlocking rod can be inserted in the placement tools 24a, 24b or in the dilator 52 to uncouple the

26/32 same as wrap 12.

ALTERNATIVE CONTROL DEVICE

Referring now to Figures 22 and 23, a control device 60 is shown. Control device 60 can be used to drive the cable (s) 27 or to place the implant 10. Consequently, the size and shape may vary significantly from those shown, since the principle of operation is widely applicable. The control device 60 has an arcuate tube 61. Preferably, the arcuate tube 61 has a radius of curvature D.

Control device 60 can be used to drive cable 27 so that cutting is not required by removing cable 27 after implantation. For example, the arcuate tube 61 has a tapered distal end 62. The tapered end 62 has radially inwardly extending pins 64 with longitudinal grooves 66 between them. The pins 64 form a distal opening 68. It is envisaged that the proximal end of the implantation cable 27 should be joined to a small sphere (not shown) at the proximal end of the cable 27. The sphere should have a diameter slightly larger than the opening 6 8 so that the sphere is captured at the tapered distal end 62. In particular, the flexible pins 64 of the cable fixing device 60 capture the sphere of the cable. When capturing the ball of the cable, the control device 60 can be used to pull the cable 27 when pulling the device 60.

Once the cable 27 has been pulled, with the implant of the locking tabs 14a-14d of the implant 10, the ball of the cable 27 is released from the tapered distal end 62 of the arcuate tube 61. The release of the ball from the control device 60 is performed by inserting a second tube 6 7 into the arcuate tube 61, as shown in Figure 22. The

27/32 second tube 57 should be slightly smaller in diameter than the arcuate tube 61. Tube 67 provides adequate force to deflect pins 64, resulting in an increase in the diameter of aperture 68 and, in turn, the release of the ball at the end of the implant cable 27. In this way, a short, predetermined amount of the cable 27 can be left implanted.

It is also envisaged that implant 10 could be designed so that the implant of flaps I4a-14d was performed starting from the tip 10a and tail 10b of the wrapper 12, bilaterally, whereby two separate cables could be used to implant the flaps 14a-14d, doubling the mechanical advantage conferred during a unilateral approach when using a single implant cable 27. Control device 60 can be used with one or both cables.

In another embodiment, the control device 60 is used to place the implant 10. The flexible pins 64 must be attached to the cutouts in the implant 10. Two control devices 60 could be used with one attached to each end of the implant 10. Of this Thus, the arcuate tubes 61 could be used to position the implant 10. When implanting the locking tabs 14a14d, the second tubes 67 must be used to release the control devices 60 from the implant 10.

USE OF LOCKING TABS FOR DIVISION

In an alternative approach, locking tabs 14a-14d are used to divide the spinal process. Instead of introducing dilators with increasing diameters, implant 10 is placed in position. Then, cable 27 is used to deploy not only the locking tabs 14a-14d, but also the locking tabs 14a-14d are dimensioned and configured to couple and distract the

28/32 spinal process. For example, each locking tab 14a-14d may have a hook-shaped protrusion positioned to divide the backbone while the tabs 14a-14d are implanted.

IMPLANT IN IMPLANT POSITION

Once implanted, the interspinal implant 10 of the present invention is joined to the adjacent spinal processes. Implant 10 provides a restriction of movement of the backbone in both extensions, as well as flexion. With slight modification of the locking tabs 14a-14d, however, the locking tabs 14a-14d could alternatively be designed to be simply adjacent to the spinal processes, and thus the implant 10 could allow flexion of the backbone.

It is also envisaged that the implant 10 can permanently couple the spinal processes. For example, the tips of the locking tabs 14a-14d can be sharpened to create penetration of the spinal processes. The ends of the locking tabs 14a-14d could be modified so that the edge forms a point on the opposite claws so that the opposite tabs could penetrate more deeply or through the bones of the spinal process. In addition, the direction of the points on the opposite claws could be reversed. In addition, the tips of the flaps 14a-14d could have one or more burrs to prevent decoupling. In addition, the tips of the flaps that 14a-14d could have perforations that allow bone growth of the spinal processes. In addition to being displaced, preferably, the curves of the locking tabs 14a-14d are slightly different to allow the opposite claws not to meet, so that each of them can penetrate more deeply through the bone.

PREDETERMINATION OF IMPLANT SIZE

Referring now to Figures 24 and 25, it is shown

29/32 an apparatus 100 and a method for percutaneously measuring the most favorable size of an interspinal implant 10, which can vary from approximately 8 mm in diameter to approximately 14 mm in diameter, depending on the anatomy of the patient and the position of the implant 10 in the spinal process. Those skilled in the art will readily appreciate that the interspinal measuring devices described in the present invention can also be used to measure or else determine the most favorable degree of force for interspinal division.

With reference to Figure 24, the measuring device 100 is shown in a closed position, since the measuring device 100 is introduced percutaneously into the interspin space. Apparatus 100 includes a proximal implantation portion 110 that includes a trigger tube 102 that contains a stem 104. The stem 104 extends approximately level with the distal end 106 of the trigger tube 102.

Apparatus 100 additionally includes a distal measuring set 112, which consists of four connected arms 114a-114d. Connected arms 114a-114d are pivotally connected to four coupling joints 115a-115d. The stem 104 of the drive tube 102 extends at the distal end to connect to the junction 115c. Adjacent to the coupling junctions 115b, 115d, there are two opposing concave bins 116a, 116b adapted and configured to couple the adjacent spinal processes.

To percutaneously measure the most favorable size of an interspinal implant 10, the apparatus 100 is placed so that the opposite concave bins 116a, 116b are between the adjacent spinal processes. The stem 104 is kept stationary while the drive tube 102 is pushed in a distal direction. The connected arms 114a-114d are directed to expand in a trapezoidal shape, such as

30/32 as shown by the movement arrows a in Figure 25). The expansion of the connected arms 114a-114d can cause the spinal processes to be divided, if this has not already been done by the dilators. A measurement of the travel distance of the stem 104 inside the tube 102 will be correlated with the length to which the interspin space was divided, i.e., the size of the trapezoidal shape. Thus, the travel distance of nail 104 can be used to determine the appropriate size of the interspin implant 10. To facilitate the measurement of travel distance, stem 104 may have graduations or markings that correspond to an actual measurement or that then identify the appropriate implant size selection 10. To measure the most favorable degree of force for interspinous distraction, the drive tube 102 and / or stem 104 are operatively associated with a strain gauge (not shown). Appropriate laboratory tests can be performed to determine the most favorable degree of distracting force so that the apparatus 100 is calibrated. The calibrated apparatus 100 can then be used to determine the appropriate implant 10 to apply that most favorable force. To calibrate the device 100, a clinical study can be done, in which the amount of distracting force is correlated with the radiological studies that show the divided degree. In addition, clinical studies can be performed, which aim at long-term clinical results, as well as the possible placement of the implant 10 in the spinal processes, with different degrees of strength exerted. Referring to Figures 26 and 27, another device 200 is illustrated to percutaneously measure the most favorable size of the interspinal implant 10 in the closed and open positions, respectively. The measuring device 200 includes an elongated body portion 210 that has a pair of jaw elements 211a, 212b at the distal end thereof for the

31/32 positioning in the interspin space. The jaw elements 212a, 212b have respective bins 214a, 214b adapted and configured to couple adjacent spinal processes. The movement of the jaw elements from the closed position of Figure 26 to the open or measuring position of Figure 27 is controlled in a conventional manner (for example, by opposing folded meat inserts or the like) by a flexible rod 216 extending through the portion body 210. For example, similarly to the trigger tube and stem, as shown in Figures 24 and 25. Again, a measurement of the travel distance of stem 216 within body portion 210 can be correlated with the length at which the interspin space was divided or directly to the appropriate implant size 10. In addition, a strain gauge can be used, for example, when coupling the strain gauge to the drive tube 102 or stem 216, to determine a preferable amount of force to be applied. It is also envisaged and framed within the scope of the present description that a temporary balloon can be introduced into the interspin space to determine the appropriate size of the implant 10 to be used. In addition, a more favorable force required for interspinous distraction can be correlated with the amount of pressure required to inflate the balloon. Thus, the size of the implant and the most favorable force must be determined by the proportion in which the balloon was inflated to obtain that most favorable pressure. Toolkit for Percutaneous Implant Placement Referring to Figure 28, a toolkit 400 is shown to facilitate percutaneous implantation of implant 10. Toolkit 400 preferably includes a housing 410 that contains, among other things, a set of stylus 30, which includes the elongated graduated positioning stylus 32, the curved stylus 34 and the adjustable bridge portion 36 with

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The dilators may, depending on whether shown on the curved guide joint 36a. Toolkit 400 is expected to include a curved stylus 34 configured for a unilateral approach to the spinal process (see Figure 13) or a curved stylus 34 'adapted and configured for a bilateral approach to the spinal process (see Figure 18), or it can include both types of curved stylets. Tool kit 400 may also include one or more 10 implants of varying sizes. In addition, toolkit 400 preferably includes a kit of tubular dilators (for example, dilators 42, 50, 52) of varying diameter that corresponds to varied implants 10 having two different lengths, dilators 42, 50, 52 are used in one bilateral approach procedure or a unilateral approach procedure. It is anticipated that tubular dilators 42, 50 may vary from approximately 8 mm or less, to approximately 14 mm or more. The dilators, curved stylus and placement tools also have different radii of curvature to accommodate the shape of different patients' bodies. Naturally, implants 10 can be packaged separately for use with an insertion kit dimensioned by the radius of curvature of the dilators, the curved stylus and the placement tools. Although the apparatus and methods of the present invention have been with reference to the preferred embodiments described, those skilled in the art will readily appreciate that changes and / or modifications can be made without departing from the character and scope of the present invention.

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