Retractor system for spinal surgery
The retractor system addresses blade dislodgment and access issues by using angled grooves and dilators, ensuring secure and efficient surgical access with reduced material strength and bulk, facilitating easier shim management.
Patent Information
- Application Number
- JP2025518988
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-10-07
- Filing Date
- 2023-09-21
- Publication Date
- 2025-10-03
AI Technical Summary
Existing spinal retractor systems face issues such as accidental dislodgment of blades due to tissue pressure, complexity in maintaining blades at the surgical site, and the need for stiff, bulky structures, making it difficult to access the site and manage shims.
The retractor system features blades with grooves oriented differently from the blade direction, allowing pins to form a retention angle, and includes a dilator for easier expansion and a shim design to prevent tissue entry, using less mechanically strong materials like plastic.
The system prevents accidental dislodgment, simplifies access to the surgical site, and allows easier management of shims, enhancing surgical precision and safety while reducing material stiffness and bulkiness.
Smart Images
Figure 2025533056000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to a surgical retractor system configured for accessing the spine using lateral, anterior, or posterior surgical techniques. [Background technology]
[0002] Spinal surgical retractor systems are used to retract and keep soft tissue away from a surgical site to allow a surgeon to access an intervertebral disc (or any other structure of the spine), for example, to partially remove the disc, and place an implant such as a cage or screw.
[0003] The retractor system typically includes at least two blades, each having a proximal portion forming a frame, two pins, each having a distal end configured to be fixed to a vertebra, and a blocking mechanism for maintaining the blades at a fixed distance from each other.
[0004] Retractor systems as defined above are disclosed, for example, in US Pat. No. 9,220,491 and US Pat. No. 10,470,753.
[0005] In some systems, each blade includes a channel configured to slidably retain one pin. See, e.g., U.S. Patent Nos. 8,852,089 and 11,426,152.
[0006] In these prior art systems, the channels are oriented along a direction parallel to the blade direction.
[0007] Shims may also be placed between the blade edges or secured to the blade to prevent unwanted or sensitive biological structures, such as tissue, nerves, or blood vessels, from entering the surgical site, and to prevent instruments from passing outside the surgical site and contacting surrounding tissue or structures. Such shims are disclosed in U.S. Patent Nos. 9,220,491, 10,470,753, or 8,821,396.
[0008] Several drawbacks are associated with prior art systems, particularly the risk of the blade being accidentally pulled out of the surgical site due to pressure exerted on the blade by surrounding tissue. Additionally, the method of expansion typically requires the use of very stiff materials and potentially bulky structures.
[0009] It is also complicated, if not impossible, to maintain the blade around the surgical site and remove only the shim, for example, to allow easier access to the surgical site. Summary of the Invention
[0010] According to the present invention, several solutions are provided to overcome the shortcomings of the prior art.
[0011] To this end, the present invention provides a retractor system for spinal surgery comprising two retractor members, each consisting of a blade and a proximal portion forming a frame, at least two pins, each having a distal end configured to be fixed to a vertebra, and a blocking mechanism for maintaining the blades at a fixed distance from each other, wherein at least one retractor member includes a channel configured to slidably hold the pin, and the at least one retractor member is characterized by including a channel configured to slidably hold the pin, the channel being oriented along a direction different from the direction of the blades.
[0012] Preferred embodiments of the invention are defined in the claims.
[0013] Other features, aspects, and advantages of the present invention will become more fully understood when considered in conjunction with the following detailed description, the appended claims, and the accompanying drawings. [Brief explanation of the drawings]
[0014] [Figure 1] 1A-1C illustrate an example of a retractor member according to the present invention. [Figure 2] 2A and 2B illustrate a pair of retractor members as shown in FIG. 1. [Figure 3] 3A and 3B show an example of a dilator member that can be used with the retractor member of FIGS. 1 and 2. [Figure 4] FIG. 4 illustrates a dilator constructed from two dilator members, as shown in FIG. 3. [Figure 5] FIG. 5 shows the dilator of FIG. 4 from above. [Figure 6] FIG. 10 shows the same dilator surrounded by two retractor members (top view). [Figure 7] FIG. 10 is a side view of a retractor with dilators and pins. [Figure 8] FIG. [Figure 9] FIG. 8 is similar to FIG. 7, but showing the angle between the pin and the associated blade. [Figure 10] FIG. 1 is a schematic diagram of forces acting on a blade and a pin. [Figure 11] FIG. [Figure 12] 12 is a view similar to FIG. 11 but taken along the pin axis. [Figure 13] FIG. 10 illustrates a retractor member having a retaining ring. [Figure 14] FIG. 16 is a perspective view of a retractor with a shim. [Figure 15] FIG. [Figure 16] FIG. 10 is a top view of a retractor with shims secured to the blades. [Figure 17]FIG. 10 shows a distal portion of a retractor with pins and shims. [Figure 18] FIG. 10 shows a distal portion of the shim. [Figure 19] FIG. 18 shows a configuration similar to that of FIG. 17 but with the shim in the lower position. [Figure 20] 1A and 1B show a shim in two different positions. [Figure 21] FIG. 1 is a top view of a retractor system relative to a spinal segment. [Figure 22] FIG. 22 is a perspective view showing a configuration similar to that of FIG. [Figure 23] FIG. 10 is a perspective top view showing another example of a retractor according to the present invention. [Figure 24] FIG. 24 is a perspective bottom view of the same object as FIG. 23. [Figure 25] FIG. 24 is a top view of the same object as FIG. 23. DETAILED DESCRIPTION OF THE INVENTION
[0015] The retractor members 1, 2 shown in Figure 1 are the main ones. The retractor members 1, 2 are also called cranial-caudal depending on their position during surgery. The retractor members 1, 2 consist of a blade 1 and a proximal part forming a frame 2 with two arms 4 each located at a different height.
[0016] Figure 2 shows a retractor base made up of the retractor members 1, 2 of Figure 1 and second retractor members 1, 2. The two frames 2 have complementary shapes such that when both retractor members 1, 2 are joined, one arm 4 of the first frame 2 is located above one arm 4 of the second frame 2, and the other arm 4 of the first frame is located below the other arm 4 of the second frame 2.
[0017] Each frame 2 includes a ratchet system 5 for holding the two retractor members 1, 2 at a fixed distance from each other.
[0018] Each blade 1 further includes a groove 3 extending along the entire length of the blade.
[0019] Groove 3 is sized to slidably retain pin 10, as defined below.
[0020] FIG. 3 shows a dilator member 6 and FIG. 4 shows a dilator made up of two dilator members 6 connected together by a guide 8.
[0021] The expander is intended to expand the retractor when positioned within the soft tissue.
[0022] The dilator has several functions, including creating a dilation from inside the retractor down the entire length of the blade 1 .
[0023] The blade 1 is then reinforced and fixed in the bone at the bottom with the help of pins 10 and at the top with the frame 2 .
[0024] This construction allows the blade 1 to be manufactured from a material that is not very mechanically strong, such as plastic.
[0025] As shown in FIG. 4, the two dilator members 6 can together form a progressive dilator, i.e., when introduced between the retractor elements 1, 2, the dilator gradually spreads the blades 1 apart from each other.
[0026] Each dilator member 6 includes a groove 9 on its outer surface designed to guide a pin 10. Together with its adjacent blade 1, which also includes a groove 3, a channel 3, 9 is formed within the retractor for guiding the pin 10. Such an arrangement offers several advantages, in particular an easier and cheaper method of manufacturing the grooves (simple surface groove milling or injection) than a very long, narrow channel (over 200 mm long, φ3.5 hole) running the entire length of the blade.
[0027] The dilator member 6 is also designed to form a K-wire channel 7 around the surgical site for initial positioning of the retractor system.
[0028] The pins 10 (see Figures 7, 8, 9, 13) serve several functions including engaging the bone, securing the blade 1 at the bone level to prevent bending of the blade under tissue pressure, and providing reinforcement as a metal frame for the blade 1, and are positioned in an innovative manner to prevent the retractor from backing out of the surgical wound.
[0029] The pin 10 may or may not be threaded and may or may not have a drive bit (hexagonal, square, male, female, ...) at the other end. Other shapes are also possible at the other end of the pin, such as an eyelet, a bend, or an attached plastic part that can be used to extract the pin by pulling on it.
[0030] 9 and 10, the channels 3, 9 formed by the retractor grooves 3 and dilator grooves 9 are oriented along a direction different from the blade direction. As a result, when the pin 10 is positioned within the channels 3, 9, the axis of the pin 10 forms an angle with the blade axis referred to as the "retention angle."
[0031] Figure 10 shows a schematic representation of the inward force (vertical arrow) exerted on the blade by the surrounding soft tissue. This force has a distally directed component (left arrow, gray). This additional force prevents the retractor from accidentally dislodging from the surgical site.
[0032] This angle provides a second advantage by allowing the pin entry location to be set back slightly from the inner surface of the blade 1, thus forming a short retaining ring 11 that keeps the pin 10 at frame level even when the expander is removed.
[0033] Shims 12 are transverse blades intended to prevent soft tissue from entering the spaces between retractor blades 1 .
[0034] The shim 12 has a distal end 13 designed to cut and enter the disc and a groove 15 to guide the shim 12 along its entire insertion into the retractor blade 1 to avoid deflection towards the patient's posterior nerves or anterior blood vessels.
[0035] Once the shim 12 is well positioned in the disc, the linear guide is interrupted at 14 to allow lateral retraction of the shim without removing or expanding the blade 1 .
[0036] Alternatively, a retractor according to the present invention may include only one arm per retractor member, in which case the frame forms a U-shape. Such an alternative is shown in Figures 23, 24, and 25. In this example, there is only one ratchet on each side.
[0037] Any suitable shape and blocking mechanism for the intended purpose may be used.
[0038] Of course, the present invention is not limited to these examples, which include lateral, anterior and posterior retractor systems.
[0039] The same considerations apply to the number of blades and pins per retractor system. [Explanation of symbols]
[0040] 1 blade 2 frames 3 blade grooves 4 Arm 5 Ratchet System 6. Expander element 7 K-wire channel 8 Guide 9 Dilator groove 10-pin 11 Retaining ring 12 Sim 13 Distal end of shim 14 Guide stop 15 Straight guide groove
Claims
1. 1. A retractor system for spinal surgery, comprising two retractor members (1, 2), each consisting of a blade (1) and a proximal portion forming a frame (2), at least two pins (10), each having a distal end configured to be fixed to a vertebra, and a blocking mechanism (5) for maintaining the retractor members (1, 2) at a fixed distance from each other, wherein at least one of the retractor members (1, 2) includes a channel (3) configured to slidably hold the pin (10), wherein the retractor system is characterized in that the channel (3) is oriented along a direction different from that of the blades (1).
2. The retractor system of claim 1, wherein the channel (3) extends along the entire length of the blade.
3. The retractor system according to claim 1 or 2, wherein the channel is a groove (3).
4. The retractor system of any one of claims 1 to 3, wherein the distal portion of the channel is a groove (3) and the proximal portion of the channel is a ring (11).
5. The retractor system of any one of claims 1 to 4, wherein each blade (1) includes a channel (3) configured to slidably retain one pin (10).
6. 6. The retractor system of claim 3, 4 or 5, further comprising a dilator for expanding the retractor, said dilator configured to be slidably mounted between said blades (1).
7. The retractor system of claim 6, wherein the dilator includes at least one groove (9) configured to slidably retain the pin (10) with a groove (3) of the blade.
8. 8. The retractor system according to claim 6 or 7, wherein the dilator is made up of two members (6) connected to each other by a guide (8).
9. The retractor system of any one of claims 6 to 8, wherein the expander has a radiopaque distal end or includes any kind of marker that can be used to measure or control the position of a cage or implant placed between the vertebral bodies.
10. The retractor system of any one of claims 1 to 9, comprising a shim (12) located between the blades (1).
11. The retractor system of any one of claims 1 to 10, wherein each retractor member includes two arms.
12. The retractor system of any one of claims 1 to 10, wherein each retractor member includes only one arm.
13. A retractor system for spinal surgery comprising two blades (1), each having a proximal portion forming a frame (2), a blocking mechanism (5) for maintaining the blades (1) at a fixed distance from each other, and at least one shim (12) slidably mounted between the blades (1) and having a transversely linear guide groove (15), wherein the retractor system is characterized in that the guide groove terminates before the distal end (13) of the shim.
14. A retractor system for spinal surgery comprising two blades (1), each having a proximal portion forming a frame (2), a blocking mechanism (5) for maintaining the blades (1) at a fixed distance from each other, and at least one expander (10) for expanding the retractor, wherein the expander is configured to be slidably mounted between the blades (1).
15. 15. The retractor system of claim 14, wherein the dilator includes at least one groove (9) configured to slidably retain a pin (10) with a groove (3) of the blade.
16. 16. The retractor system according to claim 14 or 15, wherein the dilator is made up of two members (6) connected to each other by a guide (8).
17. 17. The retractor system of any one of claims 14 to 16, wherein the expander has a radiopaque distal end or includes any kind of marker that can be used to measure or control the position of a cage or implant placed between the vertebral bodies.