Methods and Devices for Portal Fixation to the Spine

A method and device for attaching a curvilinear access device having a movable top and an expandable working portal to the spine, the attachment including a holding arm assembly, posterior tang, anterior tang and/or a portal fixation pin.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments disclosed herein are merely exemplary of the invention. 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.

Many of the embodiments disclosed herein are disclosed with curvilinear spinal access methods and devices using in a posterior-lateral approach to the spine, such as the guided lumbar interbody fusion (GLIF) using the curvilinear or Arc portal disclosed in co-pending U.S. patent application Ser. Nos. 12/460,795 and 12/069,721, the entire disclosures of these applications are incorporated by reference. Embodiments of the present invention should not be limited curvilinear access methods and devices, and also should not be limited to a posterior-lateral approach. Embodiments of the present invention may also be used in many other surgical approaches to the spine, such as anterior (ALIF), posterior (PLIF), transverse (TLIF), and extreme lateral (XLIF). Embodiments of the present invention should also not be limited to the spine and may be used in other orientations and other surgical sites within the body.

A guided lumbar interbody fusion (GLIF) procedure begins with placing a patient100in a prone position on the surgical table110and, with the aid of lateral fluoroscopy120, adjusting the patient so that the operative disc space is generally perpendicular with the operating room floor, shown inFIG. 1. The GLIF technique accesses the lateral anterior spine through a curvilinear portal, the Arc Portal, while the patient is in the prone position for the purposes of implanting a device. This access and patient orientation offers many advantages over conventional approaches including allowing a larger graft implantation, eliminating the need to reposition a patient for posterior stabilization, persevering natural posterior stabilization elements, etc.

FIGS. 2A and 2Bshow a curved access portal200having a moveable top202a,202b.Examples of curved portal devices and procedures are disclosed in U.S. patent application Ser. No. 12/460,795. The curved portal200allows curved access to the spine while the patient is in the prone position having the following advantages over traditional lumbar interbody fusion: adding posterior fixation without rotating patient, minimizing nerve compression against TP compared to a straight oblique approach, delivering an implant with better anatomic physiology without requiring drastic repositioning (like TLIF req.), protecting anterior aspect, preserving posterior elements and protecting the bowels from injury. In the expanded or open configuration, the movable top allows direct visualization through the working portal, allowing the surgeons to confirm anatomy and ensure soft tissue is protected. Once the curved portal has been inserted into the patient and coupled to the desired area of the spine, any one of many surgical procedures can now be performed through the portal, including removal of annulus material, vertebral distraction, implant insertion, fusion procedures. Tools used in these procedures may include a rotating actuator, shaver blade, osteotomes, cobbs.

The curved portal200includes the moveable top202a,202b,portal slide204, and fixation arm attachment206. The curved portal200is delivered to the patient's lateral spine208area in the closed configuration,FIG. 2Aand then the movable top is expanded or opened to provide direct visualization to the surgical site,FIG. 2B. The curved portal200is delivered over one or more dilators210, shown inFIG. 3and then can be opened in-situ after the dilators210are removed. Any number of dilators may be used. In some embodiments, the curved portal200can be supported using a holding arm assembly212attached to the fixation arm attachment206, shown inFIG. 4. The other end of the holding arm assembly212is typically attached to the surgical table or other solid support. Once in position, the surgical procedure may be done and an implant214may be inserted through the curved portal200to the desired location, shown inFIG. 5.

FIGS. 6A and 6Bshows the curved portal200in the deployed configuration including posterior216and anterior218tangs or tabs for attachment to the spine208. The posterior tang216fits within a distal attachment feature230of the curved portal200. The anterior tang218may be movably coupled to the slide portal204.

When the distal end of the curved portal200is in position at the surgical site and first opened, soft tissue typically obscures the surgeon's view of the operative site. This soft tissue needs to be identified, isolated and retracted out of the working channel of the arc portal. Previously instruments similar to elevators and penfields were used to accomplish this task; however the cantilevered forces innate to these instruments could not provide the mechanical advantage necessary to retract the soft tissue. Furthermore the free-hand nature of these tools made integrating with the connection features in the arc portal very difficult.

A posterior tang guide220, shown inFIG. 7, is used with the GLIF technique to safely and repeatedly deliver and attach the posterior tang216to the curved portal200and move the tissue material away from the surgical site.FIG. 8shows the loading of the posterior tang216into the posterior tang guide220. A knob222is turned to constrain the posterior tang216in the posterior tang guide220. The posterior tang guide220provides the necessary mechanical forces to the posterior tang216to sweep the portal clear of tissue, hold back nerve roots and tissue, and allow the posterior tang to properly integrate with the connection features in the arc portal. The posterior tang guide220allows the delivery of the posterior tang216in a safe and repeatable manner. This instrument transforms a previously cumbersome task into an easily automated procedure. The mechanisms allow tactile feedback to allow surgeons to better manipulate the soft tissue anatomy.

FIGS. 9A-9Dshow the operation of the posterior tang guide220deploying or lifting the posterior tang216(curved portal200not shown). Actuating a handle grip224of the posterior tang guide220raises a lifter226to move tissue posteriorly. When the handle224is squeezed enough a ratcheting mechanism228is engaged.

FIGS. 10A and 10Bshow the posterior tang guide220placed within the curved portal200and deploying the posterior tang216. The handle224is squeezed and released to create a scraping motion of the posterior tang216along the lateral spine to move tissue away from the working portal. When the handle224is squeezed enough for the ratcheting mechanism228to engage, the lifter228moves the posterior tang216into engagement with the distal230and proximal236attachment features in the curved portal200. The distal attachment may include distal wings on the posterior tang216that engage slots230in the curved portal200. As the posterior tang216is advanced, a springed mechanism234enables the posterior tang216catch mechanism to integrate with the proximal window236in the movable top202aof the curved portal200. At this point the lifter226exposes the remainder of the confined channel allowing the posterior tang216to advance by impacting a strike plate232. Once the posterior tang216is attached to the distal230and proximal236attachment features and coupled to the spine, the instrument220is removed, leaving the posterior tang216. As shown inFIG. 6A, the curved portal200now has two tabs, posterior tang216and anterior tang218, protruding from the distal end of the curved portal200that attach to the spine208during the procedure.

Once the working portal of curved portal200is in the open configuration, the surgeon may now perform the desired procedure which may include the implantation of an implant214, or other suitable implants. Throughout the procedure proper stabilization of the curved portal200is imperative to a successful surgery, ensuring the impaction forces do not dislodge or move the instrument from its position against the lateral spine208. In some surgeries, additional attachment means may be desired to hold the curved portal200to the spine208.

FIG. 11shows a portal fixation pin240andFIGS. 12A and 12Bshow the portal fixation pin with the curved portal200. The portal fixation pin240has a bone thread242on a distal end and a knurled barrel244with a hex features to drive the instrument into bone on a proximal end. To integrate the portal fixation pin240into the curved portal200, one or more cannulas246are added to the moveable tops202a,202bof curved portal200through which the portal fixation pin240is delivered when the tops202a,202bare in the expanded or open configuration. The portal fixation pin240may also assist in keeping or locking the tops202a,202bin the expanded configuration. The portal fixation pin240allows the curved portal200to be mechanically joined to the anterior spinal column208and prevents both separation of the curved portal200from the spine208and anterior migration of the curved portal200from the surgical site.

The portal fixation pin240is delivered through cannula246located in the hinged moveable tops202a,202bof the curved portal200. The portal fixation pin240is then driven into the vertebral body208to provide a mechanical fixation of the curved portal200against the spinal column. This fixation prevents curved portal200migration from the surgical site and prevents separation of the curved portal200from the spine208.

In some embodiments, where the present invention's device and instrumentation are used to attach an access portal to the spine for implant delivery, the implants may include, but are not limited to: bone screws, plates, interbody devices, artificial discs, or any other implants. Further, the present invention's device and methodology can be used in any number of surgical procedures, including nucleus replacement, total disc replacement, interbody fusion, discectomy, neural decompression, implant delivery (whether for fixation purposes and/or stabilization), or any other procedure.