This invention relates generally to surgical instruments and, in particular, to an instrument which is particularly suited to spinous process retraction encountered during spine surgery.
With the advent of artificial disc replacements and procedures such as posterior lumbar interbody fusion (PLIF) and transforaminal lumbar interbody fusion (TLIF), there is an increasing need to retract posterior spinal bony structures such as the spinous processes. Most surgeons use a laminar spreader for this purpose, but the use of this instrument has its drawbacks.
A typical laminar spreader is shown in
The arms 114, 116 terminate flattened tips with serrated edges 118, 120. The edges are placed between adjacent lamina to spread the lamina apart. The tool 102 is typically used after spinous processes have been removed with the lamina remaining. This instrument works well for the orientation of the laminar surface but in comparison, the spinous process contact area defines a very narrow vertical surface. As such, the tool just described can slide off or cut right through the spinous process contact area. Further, the spreading arms 114, 116 also obscure the surgeon's visualization, as the tool occupies too much space in and around the spinal midline for interspinous work.
This invention resides in a specialized surgical instrument directed to spinal surgery. The instrument is particularly configured for spinous process retraction, providing a passageway facilitating access to interspinous compartments and cooperative instrument introduction. As such, the inventive instrument solves problems associated with the use of a laminar spreader of the type just described for spinous process retraction by providing a specialized tool for this such purposes.
A spinous process retractor surgical instrument according to the invention comprises a pair of opposing proximal handles coupled to a pair of opposing distal jaws through a joint such that when the handles are compressed the jaws spread apart, the handles defining a plane when viewed from the side. The jaws curve downwardly from the plane distally from the joint, then curve back upwardly before terminating in end portions configured for spreading. The instrument defining a centerline when viewed from above, with the jaws distally from the joint diverging outwardly from the centerline, then curving back toward the centerline before terminating in the end portions.
According to a preferred embodiment, the end portions include opposing, outwardly facing textured or roughened bone-contacting surfaces. The end portions of the jaws when viewed from the sides may define a plane that is substantially parallel to the plane defined by the handles. The instrument may further include a ratcheting mechanism to lock the handles and jaws in a desired spreading configuration.
This application claims priority from U.S. Provisional Patent Application Ser. No. 61/162,416, filed Mar. 23, 2009, the entire content of which is incorporated herein by reference.
Number | Date | Country | |
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61162416 | Mar 2009 | US |