1. Technical Field
The present disclosure relates to orthopedic surgery apparatus for stabilizing and fixing the bones and joints of the body. Particularly, the present disclosure relates to a manually operated apparatus for reducing a spinal rod into a bone screw in a controlled, measured, and efficient manner.
2. Description of Related Art
The spinal column is a complex system of bones and connective tissues that provides support for the human body and protection for the spinal cord and nerves. The human spine is comprised of thirty-three vertebrae at birth and twenty-four as a mature adult. Between each pair of vertebrae is an intervertebral disc, which maintains the space between adjacent vertebrae and acts as a cushion under compressive, bending, and rotational loads and motions.
There are various disorders, diseases, and types of injury that the spinal column may experience in a lifetime. The problems may include but are not limited to scoliosis, kyphosis, excessive lordosis, spondylolisthesis, slipped or ruptured disc, degenerative disc disease, vertebral body fracture, and tumors. Persons suffering from any of the above conditions typically experience extreme or debilitating pain and often times diminished nerve function.
One of the more common solutions to any of the above mentioned conditions involves a surgical procedure known as spinal fusion. A spinal fusion procedure involves fusing two or more vertebral bodies in order to stabilize or eliminate motion at the intervertebral disc or joint. To achieve this, natural or artificial bone, along with a spacing device, replaces either part, or the entire intervertebral disc to form a rigid column of bone, which is stabilized by mechanical hardware.
The mechanical hardware used to immobilize the spinal column typically involves a series of bone screws/anchors and metal rods or plates. When the spine surgery is performed posteriorly, it is common practice to place bone screws into the vertebral bodies and then connect a metal rod between adjacent vertebral bodies. When the spine surgery is performed anteriorly, it is common practice to attach a thin metal plate directly to the vertebral bodies and secure it to each vertebral level using one or more bone screws.
The process of properly inserting the spinal rod into the receiving slot of a bone screws and then securing that connecting rod in place can often require that the clinician use a number of instruments and expend a great deal of time and effort. When bone screws in several adjacent vertebrae are to be securely connected by a spinal rod, the repeated process of inserting the rod into the screw housing of the bone screws and then securing the rod in place for each respective bone screw can be difficult, tiresome, and time consuming. Further, the alignment of the rod as it connects to each of the sequential bone screws may require adjustment during the procedure and, therefore it is desirable that an apparatus and method be provided by which the rod can be reduced into the screw housing of each of the sequentially aligned bone screws and, as necessary, easily adjusted so as to facilitate the process for the clinician with minimal effort and loss of time. Therefore, a need exits for an efficient way to reduce the rod into the screw housing and lock the rod in place.
The present disclosure is directed to a rod reducer apparatus including a housing having an opening, a shaft disposed through the opening and having threads formed thereon, and an anvil coupled to the shaft. The rod reducer apparatus further includes a button slidably disposed in the housing which is transitionable between a first position, wherein the threads of the shaft are engaged with threads on an inner surface of the button, and a second position, wherein the threads of the shaft are spaced apart from the threads on the inner surface. Additionally, first and second arm members are coupled to the housing and are configured to engage a bone screw. First and second arms are movable towards a parallel configuration as the anvil is advanced away from the housing. The rod reducer apparatus is configured such that rotation of the shaft with the button in the first position translates into linear movement of the shaft relative to the housing, while linear movement of the shaft with the button in the second position is independent of shaft rotation.
In one embodiment, the rod reduction apparatus further includes an elongated throughhole that extends through the button, the elongated throughhole is alignable with the opening such that the shaft is insertable therethrough.
In one embodiment, the shaft cooperatively engages threads of the button with the button in the first position.
In a further embodiment, the diameter of the elongated throughhole is larger than a diameter of the shaft.
In yet another embodiment, the first and second arm members are pivotably coupled to the housing.
In a further embodiment, the first and second arm members are flexibly coupled to the housing.
In one embodiment, the rod reduction apparatus further includes a spring element disposed in the housing and abutting the button.
In yet another embodiment, the spring element biases the button towards the first position.
In a further embodiment, a receiving saddle is disposed on the anvil, such that the receiving saddle cooperatively engages with a surface of a spinal rod.
In another embodiment, the receiving saddle is generally formed into an arch, and is adapted to engage with a variety of spinal rod diameters.
In one embodiment, a head at a proximal end of the shaft is adapted to cooperatively engage with a drive tool.
In another aspect of the present disclosure, a method for reducing a spinal rod into a bone screw includes, providing a rod reducer apparatus including, a housing, a shaft disposed through the housing, and an anvil coupled to the shaft. The rod reducer apparatus further includes a button that is transitionable between a first position and a second position. Additionally, first and second arm members are coupled to the housing and are configured to engage the bone screw. The rod reducer apparatus is configured such that rotation of the shaft with the button in the first position translates into linear movement of the shaft relative to the housing, while linear movement of the shaft with the button in the second position is independent of shaft rotation. The method further includes coupling the rod reducer apparatus to the bone screw, positioning the spinal rod between the anvil, the first and second arm members, and the screw housing of the bone screw, transitioning the button of the rod reducer apparatus from the first position to the second position, sliding the shaft, and anvil attached thereto, distally such that the arm members grasp the bone screw, and sliding the shaft and anvil distally such that the anvil comes into contact with the spinal rod.
In one embodiment of the present disclosure, the method may further include, transitioning the button of the rod reducer apparatus to the first position and rotating the shaft such that the shaft and anvil travel linearly with respect to the housing towards the spinal rod such that the anvil urges the spinal rod into engagement with the screw housing of the bone screw.
In yet another embodiment of the present disclosure, the method may further include, manipulating the spinal rod and bone screw into a desired orientation with the anvil securely holding the spinal rod in engagement with the screw housing.
In yet another embodiment of the present disclosure, the method may further include, transitioning the button of the rod reducer apparatus to the second position and sliding the shaft away from the spinal rod.
In a further embodiment of the present disclosure, the method may further include, decoupling the first and second arm members of the rod reducer apparatus from the bone screw.
In an embodiment of the present disclosure, the method may further include, selecting the spinal rod from a plurality of spinal rods having varying diameters, selecting the bone screw from a plurality of bone screws having a variety of sizes, and reducing the selected spinal rod into the selected bone screw.
In a further embodiment of the present disclosure, the method may further include, implanting at least one bone screw into a bone of a subject.
In another aspect of the present disclosure, a kit is provided. The kit includes a rod reducer apparatus, a plurality of bone screws, and at least one spinal rod. The rod reducer apparatus includes, a housing having an opening, a shaft disposed through the opening, and an anvil coupled to the shaft. The rod reducer apparatus further includes a button slidably disposed in the housing which is transitionable between a first position and a second position. Additionally, first and second arm members are coupled to the housing and are configured to engage a bone screw. The rod reducer apparatus is configured such that rotation of the shaft with the button in the first position translates into linear movement of the shaft relative to the housing, while linear movement of the shaft with the button in the second position is independent of shaft rotation.
The above and other aspects and features of the present disclosure will become more apparent in light of the following detailed description when taken in conjunction with the accompanying drawings in which:
Embodiments of the present disclosure are now described in detail with reference to the drawings in which like reference numerals designate identical or corresponding elements in each of the several views. As used herein, the term “clinician” refers to a doctor, a nurse, or any other care provider and may include support personnel. Throughout this description, the term “proximal” will refer to the portion of the apparatus or component thereof that is closer to the clinician and the term “distal” will refer to the portion of the apparatus or component thereof that is farther from the clinician. In addition, the term “cephalad” is used in this application to indicate a direction toward a patient's head, whereas the term “caudad” indicates a direction toward the patient's feet. Further still, for the purposes of this application, the term “lateral” indicates a direction toward a side of the body of the patient, i.e., away from the middle of the body of the patient, whereas “medial” refers to a position toward the middle of the body of the patient. The term “posterior” indicates a direction toward the patient's back, and the term “anterior” indicates a direction toward the patient's front. Additionally, in the drawings and in the description that follows, terms such as front, rear, upper, lower, top, bottom, and similar directional terms are used simply for convenience of description and are not intended to limit the disclosure.
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Operating a rod reduction apparatus in accordance with the present disclosure will be described with reference to
The clinician next positions a rod reducer apparatus 10 into proximity with each respective bone screw “BS”, such that a hook portion 34 of arm members 30 of rod reducer 10 is in near abutment to the screw housing 100 of each respective bone screw “BS”. Next, the clinician causes the hook portion 34 of the arm members 30 to grasp, clip, or otherwise affix to the screw housing 100, such that during reduction of spinal rod 200 attachment of the rod reducer 10 to the bone screw “BS”, and alignment of spinal rod 200 to the screw housing 100, is maintained. During reduction, spinal rod 200 is positioned between the screw housing 100, the anvil 40, and the arm members 30, and may be in abutment to the anvil 40 (as seen in
The clinician next reduces spinal rod 200 into seat 110 of screw housing 100. Often times there may be 15 mm or more of travel required in order to reduce spinal rod 200 fully within the seat 110 of screw housing 100 such that spinal rod 200 and screw housing 100 can be locked. Manually rotating threaded rod 50 such a distance can be cumbersome, tedious, and time consuming. The second position of button 60 of rod reducer 10 permits the clinician to perform course adjustments and quickly slide shaft 50 distally to position anvil 40 against spinal rod 200 to effect a reduction of spinal rod 200 into screw housing 100. With button 60 in the second position, shaft 50 is uncoupled from a threaded portion 66 of an elongate hole 64 disposed on the button 60, allowing shaft 50 to freely slid distally through the opening 26 of the housing 20. Free translation of shaft 50 permits anvil 40 to rapidly move distally in relation to housing 20 towards and into abutment with spinal rod 200. In the envisioned method of reducing a spinal rod, with button 60 in the second position, the clinician freely slides shaft 50 through the opening 26 of housing 20 until anvil 40 abuts spinal rod 200. The clinician continues to slide threads shaft 50, and anvil 40 attached thereto, distally causing spinal rod 200 into near abutment with screw housing 100. With a plurality of rod reducer apparatus 10, where each rod reducer apparatus 10 is mounted to a different bone screw “BS”, the clinician is able to gradually reduce the spinal rod 200 to a plurality of bone screws “BS” by sequentially reducing each rod reducer apparatus 10 all or part way until all rod reducer apparatus 10 have been actuated fully and the spinal rod 200 is reduced into all of the adjacent bone screws “BS”.
Once the anvil 40 is in abutment to spinal rod 200, and/or spinal rod 200 is in abutment to screw housing 100, the clinician may move button 60 into the first position. In the first position, shaft 50 is coupled to the threaded portion 66 of the elongated throughhole 64 of the button 60, such that the clinician may make fine adjustments and manually, or with a surgical tool (not shown), rotate shaft 50 causing anvil 40 to drive spinal rod 200 into securement with screw housing 100. In the first position, the clinician is provided a mechanical advantage of torque driven rotation of spinal rod 50.
With the rod reducer 10 attached to bone screw “BS”, it is further envisioned that the clinician may additionally use rod reducer 10 to further assist the alignment of spinal rod 200 between multiple bone screws “BS”. The clinician is provided a mechanical advantage to further bend or shape spinal rod 200 while spinal rod 200 is securely held by both rod reducer 10 and the screw housing 100 of the bone screw “BS”. In this configuration, the clinician may make final adjustments to the spinal rod 200 when connecting spinal rod 200 between multiple bone screws “BS”. After spinal rod 200 is properly aligned, the clinician may further reduce spinal rod 200 to secure the spinal rod 200 into the screw housing 100 of the bone screw “BS”.
Upon final alignment of spinal rod 200 between multiple bone screws “BS”, and/or securement of spinal rod 200 into screw housing 100, the clinician may place button 60 into the second position. In the second position, shaft 50 can again slide freely within the opening 26 of the housing 20, to permit anvil 40 to quickly and easily move proximally with respect to housing 20. Once the clinician moves shaft 50 and anvil 40 into a proximal most position (as seen in
In accordance with the present disclosure, it is envisioned that the clinician may perform the method described above with multiple bone screws “BS”, implanted in sequence to a number of vertebra, to facilitate the reduction of spinal rod 200 into and between multiple screw housings 100. It is envisioned that the clinician may be provided with multiple spinal rods 200. The clinician may perform the method described above to facilitate the reduction of multiple spinal rods 200 into multiple screw housings 100 to a number of vertebras in sequence. It is further envisioned that the clinician may be provided with multiple bone screws and spinal rods of varying sizes.
In accordance with the present disclosure, a kit will be described with reference to
While several embodiments of the disclosure have been shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of presently disclosed embodiments. Thus, the scope of the embodiments should be determined by the claims of the present application and their legal equivalents, rather than by the examples given.
The present application claims the benefit of U.S. Provisional Application Serial No. 61/887,911, which was filed on Oct. 7, 2013, the entire contents of which are incorporated herein by reference.
Number | Date | Country | |
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61887911 | Oct 2013 | US |