TOWER TOOL FOR MINIMALLY INVASIVE SURGERY
A rod reduction tool assembly includes an outer tube with outer tangs for engaging a bone anchor, an inner partially tubular pin support and a threaded cap mated to the outer tube and engaging the inner pin support.
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/852,626 filed Mar. 15, 2013, the disclosure of which is incorporated by reference herein.
BACKGROUND OF THE INVENTIONThe present invention relates to apparatus and methods for use in performing spinal surgery using minimally or less invasive techniques and, in particular, to tools and methods of using such tools, especially for reducing a rod or other longitudinal connecting member into a spinal screw.
For many years, spinal osteosynthesis apparatuses have been utilized to correct spinal deformities, injuries or disease. In such procedures, substantially rigid longitudinal connecting members, for example, elongate solid rods, are surgically attached to vertebrae of the spine to provide support and/or to realign or reposition certain vertebrae. The longitudinal connecting members are typically secured to vertebrae utilizing bone screws and other spinal implants. In order to reduce the impact of such surgery on the patient, a desirable approach is to insert such implants percutaneously or with surgical techniques that are less invasive to the body of the patient.
Problems arise when implant deployment and insertion tools designed for traditional open surgery that is more invasive are utilized in percutaneous or less invasive surgery. The tools may be bulky, oversized or have irregular surfaces or protrusions that can catch and traumatize tissues. A projecting actuator arm or fastening member may be useful with respect to the spinal screw implantation process or the rod reduction process, but there may be insufficient clearance to use such structure and/or such structure may produce additional unwanted trauma which the percutaneous surgery is attempting to avoid. A percutaneous or less invasive procedure also presents challenges in the implantation of elongate connecting members that have historically required a long incision and open wound in order to provide for the length of the connecting member and the space required for the surgeon's hands as well as the tools needed to manipulate the rod. Such problems are then compounded by the implants and insertion tools used with the connecting member.
SUMMARY OF THE INVENTIONA tool assembly according to an embodiment of the invention includes a rotate-on and rotate-off partially tubular and partially open structure providing an open or through channel, the tool for engaging and holding a bone anchor during surgery and particularly during reduction of a rod or other longitudinal connecting member into a receiver or head of a the bone anchor that is typically in the form of a monoaxial or polyaxial bone screw having spaced arms for receiving a rod or other longitudinal connecting member, such screws typically identified as “open” screws. The tool assembly includes structure at a lower end thereof that is operably mateable with outer surfaces of opposed arms of the receiver of the bone anchor. Furthermore the tool structure includes surfaces that engage both inner and outer upper surface portions of each arm of the receiver. Also, the tool structure is sized for rotating on and off of the receiver in either a clockwise or counterclockwise manner, even when a rod is located within the receiver.
A medical implant holding tool according to an embodiment of the invention includes an engagement structure at a lower end thereof operably mateable with opposed arms of an open receiver of a bone anchor, the receiver opposed arms defining a channel for receiving a longitudinal connecting member, an elongate outer holding tool with an upper tubular portion having a top surface and a first helical thread, the tubular portion terminating at a pair of opposed downwardly extending tangs located opposite the top surface, each tang having an aperture and the engagement structure for mating with one of the arms of the bone anchor receiver; and a cap having a bottom surface and a second helical thread sized and shaped for mating engagement with the first helical thread of the outer holding tool, the cap bottom surface engageable with an elongate portion and wherein rotation of the cap with respect to the outer holding tool moves the elongate portion downwardly into a location against an outer surface of the bone anchor, thereby rotationally fixing the holding tool tangs with respect to the bone anchor.
Objects of the invention include providing apparatus and methods that are easy to use and especially adapted for the intended use thereof. Other objects and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention.
The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof.
As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure.
It is also noted that any reference to the words top, bottom, up and down, and the like, in this application refers to the alignment shown in the various drawings, as well as the normal connotations applied to such tools and cooperating devices, and is not intended to restrict positioning of the tools in actual use. It is also noted that reference to words such as front, back, anterior and posterior used in this application also refer to the alignment shown in the various drawings, and in particular, when possible, with reference to the human spine and human body, but also is not intended to restrict positioning of the tools in actual use.
With reference to
With particular reference to
Because the tool assembly 1 may be used with many types of bone anchors, including hooks and other screw types, the illustrations primarily show only the top portion 12 of each arm 13 of the receiver 14 which further includes the following features: a substantially planar top surface 21; an upper outer cylindrical surface portion 22 having a central groove 23; a lower or ledge surface 24 that has an undercut; a lower cylindrical surface portion 26; an outwardly sloping surface portion 28 terminating at an outer surface 29 of the arm 13; an inner cylindrical surface 30 located adjacent the arm top surface 20; an inner sloping surface 32 that extends inwardly to a beginning of a helically would guide and advancement structure 34 that in the illustrated embodiment is a flange form; and opposed substantially planar front and back surfaces 36. As stated above, the top surface 20 is planar and circular or annular. The top surface 20 is located between and adjacent to the outer cylindrical surface 22 and the inner cylindrical surface 30, the surfaces 22 and 30 are both parallel to and run coaxial with a central axis of the receiver 14. The vertical groove 23 formed in the surface 22 is parallel to the receiver axis and is sized and shaped for slidingly receiving one of the support pins of the tool assembly 1 as will be described in greater detail below. The lower undercut surface 24 as best shown in
Returning to the tool assembly 1 and particularly to
The outer holding tool 40 is elongate and includes an upper tubular and substantially cylindrical portion 48 extending axially from a top surface 49 and generally terminating at an integral pair of opposed downwardly extending prongs, tangs or arms 50, each arm having identical opposed tooling features located near bottom surfaces 51 thereof. The arms or tangs 50 are sized and shaped for forming a through channel from the bottom surfaces 51 to the tubular upper portion 48 for receiving the rod 8 or other longitudinal connecting members or other tools or bone screw components. As best shown in
With particular reference to
Moving to a lower portion of each of the arms, at a location approximately two-thirds to three-fourths along a length of the tangs 50, a pair of opposed discontinuous helically wound square threads 80 are formed on each arm inner cylindrical surfaces 70. In the illustrated embodiment, the opposing square thread forms 80 are identical as they are configured for mating with the particular guide and advancement structure 34 of the illustrated bone screw receiver 14 that is a dual or two-start flange form structure. It is noted that the tool inner arms could be equipped with mating flange form structure. However, such is not necessary, as the square thread form 80 is sized and shaped to helically receive the flange forms on the mating closure top 9 and, unlike the flange form structure on the receiver arms, the closure top 9 does not need to frictionally fix upon anything within the tool assembly 1. Therefore, the square thread forms 80 are a more cost effective option. It is noted that the thread forms 80 may be reconfigured for rotatingly receiving and mating with closure tops having different thread-like or non-threadlike helically guide and advancement structures thereon. The assembly 1 advantageously cooperates with dual thread forms, allowing for rotate-on and off of the assembly 1 in either a clockwise or counterclockwise manner as both sides of the cooperating receiver guide and advancement structure are identical for cooperating with the dual-form closure 9. The thread forms 80 terminate at a lower implant engaging portion, generally 82, located near the bottom surfaces 51.
With particular reference to
With particular reference to
The cap 44 as best shown in
With further reference to
With reference to
With reference to
It is to be understood that while certain forms of the present invention have been illustrated and described herein, it is not to be limited to the specific forms or arrangement of parts described and shown.
Claims
1. In a medical implant holding tool having engagement structure at a lower end thereof operably mateable with opposed arms of an open receiver of a bone anchor, the receiver opposed arms defining a channel for receiving a longitudinal connecting member, the improvement comprising:
- a) an elongate outer holding tool with an upper tubular portion having a top surface and a first helical thread, the tubular portion terminating at a pair of opposed downwardly extending tangs located opposite the top surface, each tang having an aperture and the engagement structure for mating with one of the arms of the bone anchor receiver; and
- b) a cap having a bottom surface and a second helical thread sized and shaped for mating engagement with the first helical thread of the outer holding tool, the cap bottom surface engageable with an elongate portion and wherein rotation of the cap with respect to the outer holding tool moves the elongate portion downwardly into a location against an outer surface of the bone anchor, thereby rotationally fixing the holding tool tangs with respect to the bone anchor.
2. The improvement of claim 1, wherein the pin support upper portion has a cylindrical outer surface portion and the cap is slidingly received thereon.
3. The improvement of claim 2, further comprising a deformable ring partially located in an annular recess formed in the cylindrical surface portion, the deformable ring located above the cap.
4. The improvement of claim 1, wherein the tang apertures are in the form of axial through bores.
5. The improvement of claim 1, wherein the outer holding tool tubular portion is integral with the downwardly extending tangs.
6. The improvement of claim 1, wherein the inner pin support upper portion is fixed to the pair of opposed elongate pins.
7. The improvement of claim 1, wherein each tang has a first surface and an opposed second surface, the first surface sized and shaped for engaging an inner curved surface of a receiver arm and the second surface sized and shaped for engaging an outer curved surface of the receiver arm, the first and second tangs rotatably mounted on and off of the receiver arm surfaces.
8. The improvement of claim 1, further comprising an inner pin support received within the outer holding tool, the pin support having an upper portion connected to a pair of opposed elongate pins, each pin sized and shaped to extend through the aperture of one of the outer holding tool tangs.
9. In a combination of a bone attachment structure having a receiver and a medical implant holding tool having receiver attachment structure at a lower end thereof operably mateable with the receiver; the improvement wherein:
- a) the receiver has two arms, each arm having an undercut first surface projecting downwardly toward a bottom thereof and a curved surface located directly above the undercut surface; and
- b) the tool has an outer portion, an inner portion slidably received within the outer portion and a cap, the outer portion having structure in engagement with the receiver undercut surface, the inner portion having a pair of opposed pins, each pin extending through an aperture of the outer portion, the cap threadably connected to the outer portion and in abutment with the inner portion, and wherein rotation of the cap with respect to the outer portion causes the cap to press against and move the inner portion in a downward direction toward the receiver and thereby move the pair of opposed pins into engagement with the receiver arm curved surfaces.
10. The improvement of claim 9, wherein each receiver arm has an inner surface located directly above a dual start guide and advancement structure and wherein the tool engages the inner surface.
11. The improvement of claim 10, wherein the tool is rotatable on and off of the receiver in both a clockwise and a counterclockwise manner.
12. In a medical implant holding tool having engagement structure at a lower end thereof operably mateable with opposed arms of an open receiver of a bone anchor, the receiver opposed arms defining a channel for receiving a longitudinal connecting member, the improvement comprising:
- a) an elongate outer holding tool with a tubular portion having a top surface and an inner cylindrical surface having a first helical thread, the tubular portion terminating at a pair of opposed downwardly extending tangs located opposite the top surface, each tang having an aperture and the engagement structure for mating with one of the arms of the bone anchor receiver;
- b) an inner pin support received within the outer holding tool, the pin support having an upper portion connected to a pair of opposed elongate pins, each pin sized and shaped to extend through the aperture of one of the outer holding tool tangs; and
- c) a cap having a bottom surface and a second helical thread sized and shaped for mating engagement with the first helical thread of the outer holding tool, the cap bottom surface engageable with the inner pin support upper portion and wherein rotation of the cap with respect to the outer holding tool moves the pins downwardly into a location against an outer surface of the bone anchor, thereby rotationally fixing the holding tool tangs with respect to the bone anchor.
Type: Application
Filed: Mar 5, 2014
Publication Date: Sep 18, 2014
Inventors: Roger P. Jackson (Prairie Village, KS), Lawrence E. Guerra (Mission, KS), William R. Hendricks (Overland Park, KS)
Application Number: 14/197,848
International Classification: A61B 17/88 (20060101);