Patent Application
20090326543
A. Field of Invention
This invention pertains to the art of methods and apparatuses regarding spine surgery and more specifically relates to surgical procedures and an extractor used to remove an implant from a vertebral space, and perhaps to un-deploy the implant within a vertebral space.
B. Description of the Related Art
The volume of spinal surgeries to treat degenerative disc and facet disease has steadily increased over the past decade, fueled by population demographics and advancements in diagnostic and instrumentation adjuncts. Improvements in intraoperative radiological imaging and surgical technique have generated a great deal of interest in applying minimally invasive surgical (MIS) techniques to spinal applications. As in other surgical subspecialties, it is hoped such minimally invasive techniques applied to spinal surgery will result in less soft tissue trauma, less operative blood loss, reduced operative time, faster recovery periods and lower costs.
Known spinal surgical techniques, though generally working well for their intended purposes, have been adopted from traditional open surgical (non-MIS) techniques. As a result, known spinal surgical methods, instrumentation and interbody implants have limitations. One limitation is that the physical components are relatively large and bulky. This reduces surgeon visualization of the surgical site. Another limitation of known spinal surgical methods is that known surgical tools and implants are cumbersome and difficult to maneuver within the limited surgical space available. The limitations of current instrumentation in MIS spine surgery are noted particularly with regards to interbody fusion surgery.
The present invention provides methods and apparatuses for overcoming these limitations by providing a surgical extractor that allows for minimally invasive spinal surgery and that provides for precise movement, placement and undeployment of an implant within the vertebral space.
According to one embodiment of this invention, a surgical extractor for use in extracting an implant from a vertebral space, may include: (1) a first handle for use by a surgeon in maneuvering the surgical extractor, the first handle having an opening; and, (2) an implant gripping mechanism comprising: (A) a first grip member having a first end attached to the first handle and a second end comprising a first contact surface; and, (B) a second grip member having a first end threadingly received within the opening in the first handle and a second end comprising a second contact surface. The first handle can be rotated in a first direction with respect to the second grip member to cause the first and second contact surfaces to move relatively toward each other to grip the implant. The first handle can also be rotated in a second direction with respect to the second grip member to cause the first and second contact surfaces to move relatively away from each other to release the implant.
According to another embodiment of this invention, the first and second contact surfaces are shaped to match the surfaces of the implant which they contact.
According to another embodiment of this invention, the extractor also has a second handle for use by a surgeon in maneuvering the surgical extractor.
According to yet another embodiment of this invention, a surgical system may include: (I) an implant comprising: (A) a first portion having a first engagement surface; (B) a second portion having a second engagement surface; and, (C) the implant may be deployed within a vertebral space by moving the second portion with respect to the first portion in a first direction; and, (II) a surgical extractor for use in un-deploying the implant within the vertebral space and for use in extracting the implant from the vertebral space, the surgical extractor comprising: (A) a first handle for use by a surgeon in maneuvering the surgical extractor, the first handle having an opening; (B) an implant gripping mechanism comprising: (1) a first grip member having a first end attached to the first handle and a second end comprising a first contact surface; and, (2) a second grip member having a first end threadingly received within the opening in the first handle and a second end comprising a second contact surface. The first handle may be rotated in a first direction with respect to the second grip member to: (1) cause the first contact surface to contact the first engagement surface; (2) cause the second contact surface to contact the second engagement surface; (3) cause the implant to be un-deployed within the vertebral space by moving the second portion with respect to the first portion in a second direction that is substantially different than the first direction; and, (4) grip the implant for removal from the vertebral space.
According to another embodiment of this invention, the first engagement surface is on a first implant post; and, the second engagement surface is on a second implant post.
According to still another embodiment of this invention, a method comprising the steps of: (A) providing an implant positioned within a vertebral space, the implant having first and second engagement surfaces; (B) providing a surgical extractor comprising: (1) a first handle for use by a surgeon in maneuvering the surgical extractor, the first handle having an opening; (2) an implant gripping mechanism comprising: (a) a first grip member having a first end attached to the first handle and a second end comprising a first contact surface; and, (b) a second grip member having a first end threadingly received within the opening in the first handle and a second end comprising a second contact surface; (C) providing access to the vertebral space; (D) rotating the first handle with respect to the second grip member to cause the first and second contact surfaces to move relatively toward each other; (E) continue rotating the first handle with respect to the second grip member to cause the first and second contact surfaces to engage the first and second engagement surfaces, respectively, to grip the implant; and, (F) moving the surgical extractor and thereby the implant away from the vertebral space.
One advantage of this invention is that the inventive surgical extractor permits an implant to be relatively easily removed from a vertebral space.
Another advantage of this invention is that the implant may be relatively easily and securely attached to the extractor and then detached from the extractor.
Another advantage of this invention is that, in one embodiment, the extractor can be used to un-deploy the implant.
Yet another advantage of this invention is that the surgical extractor allows for minimally invasive application via either an anterior, anterolateral, posterior or posterolateral approach, with the latter approach possible via either a transforaminal or extraforaminal approach.
Still other benefits and advantages of the invention will become apparent to those skilled in the art to which it pertains upon a reading and understanding of the following detailed specification.
The invention may take physical form in certain parts and arrangement of parts, embodiments of which will be described in detail in this specification and illustrated in the accompanying drawings which form a part hereof and wherein:
Referring now to the drawings wherein the showings are for purposes of illustrating embodiments of the invention only and not for purposes of limiting the same, the surgical extractor 200, 200a of this invention can be used to extract and, in some embodiments such as shown by comparing
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With reference now to all the FIGURES, the extractors 200, 200a of this invention may be used to remove or extract and, if required, un-deploy any implant chosen with the sound judgment of a person of skill in the art. To understand the meaning of the term “un-deploy,” the term “deploy” will first be described. The term “deploy” as used in this patent refers to any adjustment of an implant after the implant has been initially placed into the vertebral space that involves relative motion of one portion of the implant with respect to another portion of the implant. Non-limiting examples of deployment include implants that have one portion that pivots or moves curvilinearly with respect to another portion and implants that have one portion that slides or moves linearly with respect to another portion. Implants that expand in any manner and in any direction fall under the definition of “deploy.”
The term “un-deploy” as used in this patent refers to any adjustment of a deployed implant within the vertebral space that involves relative motion of one portion of the implant with respect to another portion of the implant. In one embodiment, un-deployment of an implant means returning the implant to its pre-deployed condition. However, it is not necessary for the implant to be returned to its pre-deployed condition for it to be un-deployed according to this patent. It should also be noted that the not all implants are deployable. If this is the case, it should be noted that the extractors 200, 200a of this invention as described above will work well to extract such an implant.
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With reference again to all the FIGURES, the operation of the extractor 200 of this invention will now be described. First, it should be noted that the implant 100 may have been inserted within the vertebral space 22 in any manner. The implant may be inserted, for non-limiting examples, by any of the insertion techniques and devices described in commonly owned U.S. patent application Ser. No. 11/756,168, titled SPINE SURGERY METHOD AND INSTRUMENTATION and commonly owned U.S. patent application Ser. No. 11/108,625, titled SPINE SURGERY METHOD AND INSERTER, both of which are incorporated herein by reference. In one embodiment, the implant is extracted during the same surgical procedure as when the implant is inserted. This may occur, for some non-limiting examples, when the surgeon discovers that the implant is the wrong size for the patient, that the implant will not deploy properly, or that there are unexpected difficulties related to the patient's spine structure. In another embodiment, the implant is extracted in a separate surgical procedure from the surgical procedure used to insert the implant using any method chosen with the sound judgment of a person of skill in the art. The vetebral space 22 and the implant may be approached, for example, using universally accepted methods for anterolateral, posterior, or posterolateral (transforaminal) discectomy.
With continuing reference to all the FIGURES, once the implant type, style, and size has been determined, the surgeon determines what two surfaces of the implant 100 will be used as the first and second engagement surfaces 102, 104, which are to be gripped by the extractor 200 or 200a. Next, the surgeon assembles the appropriate extractor. It should be noted that the same handle mechanism 300 can be used with numerous implant gripping mechanisms 400. The specific dimensions of the first grip member 402 and the second grip member 420, for example, can be any chosen to properly access and grip the implant to be extracted and may vary, for example, depending on patent parameters (such as patient size) and whether the spinal surgery is done open or via MIS techniques. The surgeon may decide to use a gripping mechanism 400 that has at least one of the contact surfaces 426 or 428 with a shape to match the corresponding at least one of the shapes of the engagement surfaces 102 or 104. For the specific embodiment shown, both of the contact surfaces 426, 428 as well as both of the engagement surfaces 102, 104 are curvilinear. The use of matching surfaces may improve the ability of the implant gripping mechanism 400 to grip the implant 100. As noted above, in another embodiment the connection of the contact surface 426 and/or 428 to the corresponding engagement surface 102 and/or 104 may include a pin in slot connection. However, it should be noted that it is not required that the contact surfaces 426, 428 match the engagement surfaces 102, 104.
Still referring to all the FIGURES, once the surgeon has access to the implant 100 within the vertebral space 22 and is satisfied that the correct extractor 200, or 200a has been assembled, a distractor (not shown) is then placed within the vetebral space 22 and distraction to the selected level of annular tension to remove the implant 100 is achieved. The degree of this distraction would be based on surgeon preference and/or the implant 100 height. With this optimal distraction, further discectomy, or removal of disc material, may be accomplished if required.
With continuing reference to all the FIGURES, the extractor 200 or 200a is then affixed or gripped to the implant 100 using the implant gripping mechanism 400. More specifically, the surgeon first determines the desired space required between the first and second contact surfaces 426, 428 to permit the extractor 200, 200a to grip the implant 100. This desired space between the first and second contact surfaces 426, 428 may be achieved by rotating the handle 302 with respect to the second grip member 420 as described above. If the extractor 200a uses the second handle 330, the surgeon may grip the second handle 330 with one hand while rotating the handle 302 with the other hand. Next, the surgeon maneuvers the extractor 200 or 200a using the handle mechanism 300 into place juxtaposed to the implant 100. The surgeon then rotates the handle 302 with respect to the second grip member 420 to decrease the space between the first and second contact surfaces 426, 428. The surgeon continues this rotation until the first and second contact surfaces 426, 428 are properly in contact with the engagement surfaces 102, 104 of the implant 100. In one specific embodiment, the first engagement surface 102 is on the outer surface of one of the posts 106 on a first portion 110 of the implant 100 and the second engagement surface 104 is on the outer surface of one of the posts 108 on a second portion 112 of the implant 100.
Still referring to all the FIGURES, the next stage of surgery depends on whether the implant 100 needs to be placed into a un-deployed condition before it is to be extracted. If it does, then the surgeon continues the rotation of the handle 302 with respect to the second grip member 420 to decrease further the space between the first and second contact surfaces 426, 428 thereby causing relative motion of one portion of the implant 100 with respect to another portion of the implant 100 to achieve the un-deployed condition. In one specific embodiment, as the space between the first and second contact surfaces 426, 428 is decreased, the first portion 110 of the implant 100 pivots with respect to the second portion 112 about, for example, a pivot point 114.
With continuing reference to all the FIGURES once the implant 100 is in the desired condition (un-deployed or not) to be removed, the surgeon now simply moves the extractor 200 or 200a and thus the implant 100 which is gripped by the extractor using the handle mechanism 300 outside of the vertebral space 22 and then outside of the patient. After the implant 100 is removed from the patient, it may be removed from the extractor 200 or 200a by rotation of the handle 302 with respect to the second grip member 420 to increase the space between the first and second contact surfaces 426, 428 until the implant 100 is released. After the implant 100 is removed, the surgeon can insert a new implant and/or perform any additional surgical techniques that may be required.
Still referring to all the FIGURES, it should be noted that all the extractor embodiments may be formed of any biocompatible material suitable for surgical instruments.
Multiple embodiments have been described, hereinabove. It will be apparent to those skilled in the art that the above methods and apparatuses may incorporate changes and modifications without departing from the general scope of this invention. It is intended to include all such modifications and alterations in so far as they come within the scope of the appended claims or the equivalents thereof.
