WO2009094057A1

WO2009094057A1 - Muscle saving device, surgical site barrier and method

Info

Publication number: WO2009094057A1
Application number: PCT/US2008/080931
Authority: WO
Inventors: Jeffery Thramann
Original assignee: Lanx, Inc.
Priority date: 2008-01-24
Filing date: 2008-10-23
Publication date: 2009-07-30

Abstract

A method, kit, and system to separate muscle fiber prior to threading pedicle screws and a barrier to inhibit tissue creep into the surgical site and/or resist withdrawal of a dilator. By separating the muscle fiber prior to threading the pedicle screws, the muscle fiber does not need to be cut to place rods, which facilitates minimally invasive surgical methods.

Description

MUSCLE SAVING DEVICE, SURGICAL SITE BARRIER AND METHOD

CROSS-REFERENCE TO RELAlED APPLICATIONS This application is a continuation-in-part of U.S. Application No. 11/135,685, filed May 24.2005, the disclosure of which is incorporated herein as if set out in full. This application also claims the benefit of U.S. Provisional Application No. 60/887,093, filed January 29, 2007, the disclosure of which is incorporated herein as if set out in full 2007.

FIELD OF THE INVENTION

[01] The present invention relates io a device useful in saving muscle during surgery and, more particularly, to a device useful in minimally invasive spinal surgery to avoid or reduce cutting muscle fiber along the spine.

BACKGROUND

[02] Minimally invasive surgery is preferable to non-minimally invasive surgery. Conventionally, many spinal surgeries include the placement of implants through minimally invasive techniques.

[03] However, conventional methods and devices still require cutting muscle tissue about the spine decreasing the effectiveness of the minimally invasive procedure. For example, and much abbreviated from the actual procedure, when placing a rod and two pedicle screws, a surgeon may use a navigation system to locate where the surgeon wants to place the screw. The surgeon inserts a guide wire and dilator to the located point and threads the pedicle screw into the pedicle. The surgeon repeats the process for the second pedicle screw. Once the screws are placed, a surgical incision is made to provide access such that a spinal rod can be inserted between the screws. Except by happenstance, the surgeon will cut through muscle fiber to insert the spinal rod. Cutting the muscle reduces the effectiveness of the minimally invasive surgery. [04] It would be advantageous to develop a device and method that would drastically reduce the cutting of muscle fiber during minimally invasive surgical procedures. SUMMARY

[05] To attain the advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, devices and a method for saving muscle during surgery are provided.

[06] In one aspect of the invention, a method to save muscle during a spinal surgical procedure includes locating a first place on a first pedicle to thread a first pedicle screw; inserting a first guide wire at the first place; inserting a first dilator over the first guide wire to separate muscle fiber and created a dilated area; expanding the dilated area to separate the muscle fiber from the first pedicle to a second pedicle; exposing the surgical area with the muscle fiber separated; and enlarging a barrier adjacent the surgical area.

[07] In another aspect of the invention, a muscle saving kit useful for minimally invasive surgical procedures includes a dilator defining a surgical passageway from the first end to the second end and an inflatable barrier mounted to the second end and being inflatable to create a radially expanding flange at the second end,

[08] In another aspect of the invention, a system for installing pedicle screws and at least one connecting device connecting the pedicle screws includes a guide wire, a series of successively sized dilators, and a final dilator. The series of successively sized dilators includes at least one muscle fiber separating dilator and the final dilator includes an inflatable barrier mounted to one end and being inflatable to create a radially expanding flange at the end of the final dilator. [09] The foregoing and other features, utilities and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention as illustrated in the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[010] Various examples of the present invention will be discussed with reference to the appended drawings. These drawings depict only illustrative examples of the invention and are not to be considered limiting of its scope.

[011] FlG. I is a top plan view of a muscle over a superior pedicle and an inferior pedicle; 012] FIG. 2 is a side elevation view of FIG. 1;

013] FIG. 3 is a top plan view of a series of nesting dilators according to the present invention; [014] FlG. 4 is a top plan view of the muscle of FIG. 1 with a guide wire and dilator separating muscle fibers consistent with an embodiment of the present invention; [015] FIG. 5 is a top plan view of the muscle of FIG. 1 with a subsequent dilator separating muscle fibers extending between the superior pedicle and the inferior pedicle; [016] FlG. 6 is a top plan view of the muscle of FIG. 1 with a plurality of subsequent dilators separating muscle fibers to expose the surgical site without needlessly cutting muscle fiber; [017] FlG. 7 is a top plan view of the muscle of FIG. 1 with a final fixed dilator separating muscle fibers and exposing the surgical site without needlessly cutting muscle fiber; [018] FIG. 8 is a flowchart outlining possible procedural steps useful in using the muscle saving device consistent with the present invention;

[019] FIG. 9 is a perspective view of a dilator with a site barrier consistent with the technology disclosed by the present application; and

[020] FIG. 10 is a flowchart outlining possible procedural steps for implementing the barrier of FlG. 9. DESCRIPTION OF THE ILLUSTRATIVE EXAMPLES

[021] The present invention will now be described with reference to FIGS. 1 to 10. Referring first to FIGS. 1 and 2, a posterior view and a lateral view of a spinal segment 100 is shown. The figures are not drawn to scale and only show those portions of the anatomy necessary to understand the present invention. Segment 100 has a layer of muscle 102 comprising substantially parallel muscle fibers 104. Muscle 102 resides posterior to a superior pedicle 106 and an inferior pedicle 08.

[022] To implant a rod between superior pedicle 106 and inferior pedicle 108, a surgeon would locate and place a guide wire 200 using conventional navigation technologies on superior pedicle 106, for example, although the surgeon could start with inferior pedicle 108. Next, a dilator would be inserted over the guide wire 200 to provide surgical access through the skin. Conventionally, at this point, the dilator would be removed and a pedicle screw would be threaded over the guide wire 200.

[023] Referring now to FIG. 3, in the present invention a series of dilators are provided for separating muscle fibers without cutting the fibers. A first dilator 400 includes an outer surface 402 and an inner passageway 404 sized to receive the guide wire 200 in a close fit sliding relationship. A second dilator410 includes an outer surface 412 and an inner passageway 414 sized to receive the outer surface 402 of the first dilator 400 in a close fit sliding relationship. A third dilator 420 includes an outer surface 422 and an inner passageway 424 sized to receive the outer surface 412 of the second dilator 410 in a close fit sliding relationship. A fourth dilator 430 includes an outer surface 432 and an inner passageway 434 sized to receive the outer surface 422 of the third dilator 420 in a close fit sliding relationship. A fifth dilator 440 includes an outer surface 442 and an inner passageway 444 sized to receive the outer surface 432 of the fourth dilator 430. [024] Referring now to FIGS. 4-7, the use of the dilators 400, 410, 420, 430, 440 will be described. After the guide wire 200 is placed at the desired surgical site; e.g. superior pedicle 106; the first dilator 400 is slid over the guide wire 200 and pressed through the muscle 102 to separate muscle fibers 104 and create a path to the superior pedicle 106 and an exposure area 306 exposing the superior pedicle 106. Next, at least one additional dilator, and typically a series of dilators, is inserted over the first dilator 400. Referring now to FIG. 5, the second dilator 410 is shown inserted over the first dilator 400. The second dilator 410 expands exposure area 306 towards the next pedicle, which in this case is inferior pedicle 108. [025] Referring now to FIG. 6, the spinal segment 100 is shown with third and fourth dilators 420, 430 installed over first and second dilators 400, 410. A sufficient number of dilators have been installed to expose the inferior pedicle 108 in a second exposure area 502. While all the dilators are shown as successively inserted with the previous dilator remaining in place, the previous dilators can be removed before, during, or after each subsequent dilator is placed.

[026] Referring now to FIG. 7, once the appropriate portion of pedicle 108 is exposed, fifth dilator 440 is inserted and any remaining previous dilators are removed providing a surgical access 604 between superior pedicle 106 and inferior pedicle 108 along a particular muscle fiber 104. If the guide wire 200 has been removed it is now replaced in a desired location in the superior pedicle 106 and an additional guide wire 210 is place in the inferior pedicle. Pedicle screws may now be threaded over the guide wires 200, 210 in a conventional manner. Since the muscle fibers 104 move relatively freely in the transverse direction 150 the dilators and muscle may be moved transversely to locate the dilators to expose the desired portion of the pedicles 106, 108. Thus, the location of the guide wires 200, 210 and eventually the pedicle screws can be established as desired. Because the muscle fibers 104 were separated from the superior pedicle 106 to the inferior pedicle 108 no muscle fibers 104 had to be cut and a rod can thus be inserted between the pedicle screws without cutting across the muscle fibers 104. The rod may be installed using any conventional method.

[027] In the illustrative embodiment, the first dilator 400 is shown with a cylindrical shape and the second, third, and fourth dilators 410, 420, 430 are shown having a leading edge giving it a knife, tear drop, or wedge shape. However, the dilators may be any shape including all cylindrical, all wedge-shaped, and/or any combination of these and/or other suitable shapes. However, it is believed that the wedge shape of the second, third, and fourth dilators 410, 420, 430 will assist in spreading the muscle fibers. Likewise, although the fifth dilator 440 is shown as a generally rectangular shape, it may have any suitable shape. The invention has been illustrated with five dilators, however, any number of dilators may be provided. [028] Also, instead of, or in addition to successive dilators, a means of expanding one or more of the dilators may be provided. Such as, for example, the use of a gas to pressurize the dilator and designing the dilator so it can expand in only the desired direction In another example, the dilator may be made out of an expandable material, such as, a shape memory alloy that can be caused to expand on activation. In another example, the dilator may include a hinged portion that expands and separates muscle fibers. In one illustrative embodiment, the second dilator 410 (FIG. 5), may include at least one substantially rigid portion 416 and at least one substantially elastic portion 418. The at least one substantially rigid portion 416 would reside at least at the portion of dilator 410 that was not to expand. A leading edge 419 may also be relatively rigid if desired to facilitate muscle fiber separation. While the example above is described with the second dilator, the first dilator 400 could be expandable making subsequent dilators optional. [029] For completeness, FIG. 8 is a representative flowchart 700 of using the present invention. First, a surgeon locates a pedicle screw placement on a first pedicle and inserts a guide wire, step 702. Next, the surgeon places a dilator over the guide wire, step 704. A series of dilators are inserted to spread the muscle fiber without cutting the fiber from a first pedicle to a second pedicle, step 706. Successive dilators are external and larger than preceding dilators. Step 706 is repeated until the surgical area between pedicles is exposed. Once the surgical area is exposed, a final dilator is placed extending between first pedicle and second pedicle and exposing a surgical area, step 708. To the extent one or more expandable dilators are used, step 706 may be replaced or further include a step of expanding the dilator to spread the muscle fiber until the surgical area between pedicles is exposed. Moreover, the first dilator or the final dilator can be an expandable dilator and/or the final dilator that actually spreads muscle. Any remaining preceding dilators are removed, step 710. A second pedicle screw placement is located, step 712. Finally, the muscle fibers are laterally aligned such that the surgical area encompasses the first and second pedicle screw placement areas, step 714. Note that location of the second pedicle screw can be done before or after dilation of the muscle fiber. Moreover, and optionally, preceding internal dilators can be removed subsequent to placement of an external dilator, step 707. The second guide wire 210 can be inserted using surgical navigation techniques. [030] While the above described system works satisfactory, in some cases, tissue and fibers may creep under the final dilator and into the surgical area. Furthermore, the dilator may tend to rise up away from the surgical site. Referring now to FIG. 9, a perspective view of a final dilator, access port, or tube 800 is shown. Tube 800 has an access portion 802 traversing from above the patient's skin (not specifically shown) to a distal edge 804 proximate the surgical site 806. An inflatable barrier 808 is attached to the distal edge 804. The inflatable barrier 808 is preferably defoπnable to conform to the patient's anatomy. The inflatable barrier 808 is inflatable to create a radially projecting flange adjacent the distal edge 804. The inflatable barrier 808 needs to be sufficiently strong to inhibit tissue creep under the barrier 808 and into the surgical site 806. In a preferred embodiment, the inflatable barrier 808 is formed as a fluid bladder from an inflatable plastic or synthetic material. The inflatable barrier includes a fluid valve 810 to allow fluid to be supplied to and optionally released from the inflatable barrier 808. The fluid valve 810 may be any conventional valve. The fluid valve 810 is connectable to a fluid supply via a conduit. In the example of FTG. 9, fluid is supplied by a syringe 812 and injected into the valve with a needle 814. However, pre-pressurized fluid cartridges, medical facility fluid supplies, and/or other fluid supplies may be used. The fluid may be air, nitrogen, carbon dioxide, water, saline, mineral oil, and/or any other suitable gas or liquid. The inflatable barrier 808 is preferably puncture and rupture resistance, such as for example the material used for balloons supplied by Kyphon, Inc. 1350 Bordeaux Drive Sunnyvale, CA 94089. [031] Referring now to FlG. 10, a method 900 of using an inflatable barrier 808 is provided. First, the tube 800 is placed consistent with the procedure outlined in FIG. 7, step 902. Next, a fluid supply is connected to the inflatable barrier 808, step 904. Finally, the inflatable barrier 808 is inflated to expand radially outwardly from the distal edge and provide a barrier to inhibit tissue from creeping under the barrier into the surgical site and/or to resist movement of the tube 800 away from the surgical area, step 906. The surgical procedure is performed, step 908. Optionally, the barrier is deflated, step 910. Once access to the surgical site is no longer necessary, the tube 800 is removed, step 912. [032] An embodiment of the present invention and many of its improvements have been described with a degree of particularity. It should be understood that this description has been made by way of example, and that the invention is defined by the scope of the following claims.

Claims

CLAIMS What is claimed is.

1. A method to save muscle during a spinal surgical procedure, the method comprising: locating a first place on a first pedicle to thread a first pedicle screw; inserting a dilator at the first place to separate muscle fiber and created a dilated area, expanding the dilated area to separate the muscle fiber from the first pedicle to a second pedicle; exposing the surgical area with the muscle fiber separated; and enlarging a barrier mounted to the dilator adjacent the surgical area.

2. The method of claim 1, wherein the step of expanding the dilated area comprises the step of expanding the dilator at least in a direction toward the second pedicle.

3. The method of claim 1 , wherein the step of expanding comprises inserting at least another dilator over the dilator to separate muscle fiber.

4. The method of claim 1 , wherein enlarging a barrier comprises inflating a flexible container attached to an end of the dilator

5. The method of claim 4 wherein inflating a flexible container comprises inflating a flexible container to trap tissue and prevent it from moving into the surgical area.

6. The method of claim 4 wherein inflating a flexible container comprises inflating a flexible container to expand the end of the dilator to resist withdrawal of the dilator from the surgical area.

7. The method of claim 4 wherein inflating a flexible container comprises injecting a fluid into the flexible container, the method further comprising removing at least a portion of the fluid after the surgical procedure is completed.

8. The method of claim 1, further comprising the steps of threading a first pedicle screw into the first pedicle, threading a second pedicle screw into a second pellicle, and implanting a rod between the first pedicle and the second pedicle without cutting muscle fiber.

9. The method of claim 1, wherein the surgical area encompasses at least a third pedicle located between the first pedicle and the second pedicle.

10. The method of claim 1, wherein the step of inserting at least one additional dilator includes inserting a plurality of dilators where each successive dilator is larger than each proceeding dilator.

1 1. The method of claim 10, wherein the step of inserting a plurality of dilators includes the step of removing proceeding dilators.

12. A muscle saving kit useful for minimally invasive surgical procedures, comprising: at least one dilator having a first end, a second end, and an axis extending from the first end to the second end, the dilator defining a surgical passageway from the first end to the second end; and an inflatable barrier mounted to the second end and being inflatable to create a radially expanding flange at the second end.

13. The muscle saving kit of claim 12 wherein the at least one dilator comprises at least one muscle separating dilator, the at least one muscle separating dilator being sized to separate muscle fibers between a first pedicle and a second pedicle such that a surgical area is exposed and a final dilator, the final dilator being sized to maintain the separation of the separated muscle fibers and provide surgical access to the surgical area, the inflatable barrier being mounted to the final dilator.

14. The muscle saving Kit or Claim 12, wnerein tne at least one muscle separating dilator comprises a plurality of dilators.

15. The muscle saving kit of claim 12, wherein the at least one muscle separating dilator has a leading edge to facilitate separation of muscle fibers.

16. The muscle saving kit of claim 15, wherein the muscle separating dilator has a shape selected from the group of shapes consisting of: a knife shape, a tear drop shape, or a wedge shape.

17. The muscle saving kit of claim 12, wherein the final dilator has a shape selected from the group of shapes consisting of: a substantially circular shape, a substantially elliptical shape, a substantially rectangular shape, or a substantially square shape.

18. The muscle saving kit of claim 12, wherein the at least one muscle separating dilator is expandable in a direction from the first pedicle to the second pedicle.

19. A system for installing pedicle screws and at least one connecting device connecting the pedicle screws that saves muscle fiber from being cut, the system comprising: a guide wire, the guide wire being able to be located and inserted to determine placement of a first pedicle screw in a first pedicle; a series of successively sized dilators, the series of successively sized dilators comprises at least a first dilator insertable over the first guide wire, at least one muscle fiber separating dilator insertable to separate the muscle fiber between the first pedicle and a second pedicle; a final dilator having an end and being insertable to maintain muscle fiber separation; and an inflatable barrier mounted to the end of the final dilator and being inflatable to create a radially expanding flange at the end of the final dilator.

20. The system of claim 19, further comprising: a first pedicle screw; a second pedicle screw; and a connecting rod engageable with the first and second pedicle screws to maintain the first and second pedicle screws in fixed spaced relationship.