STEREOTAXY WAND AND TOOL GUIDE
This application, a continuation-in-part of U.S. application Ser. No. 08/224,955, filed Apr. 8, 1994, now U.S. Pat. No. 5,517,990 which, in turn, is a continuation-in-part of U.S. Application Ser. No. 07/983,390, filed Nov. 30,1992, now U.S. Pat. No. 5,309,913.
BACKGROUND OF THE INVENTION
The present invention relates to the medical diagnostic and surgical arts. It finds particular application in conjunction with neurosurgery and will be described with particular reference thereto. However, it is to be appreciated, that the invention will also find application in conjunction with neurobiopsy, CT-table needle body biopsy, breast biopsy, endoscopic procedures, orthopedic surgery, other invasive medical procedures, industrial quality control procedures, and the like.
Three-dimensional diagnostic image data of the brain, spinal cord, and other body portions is produced by CT scanners, magnetic resonance imagers, and other medical diagnostic equipment These imaging modalities typically provide structural detail with a resolution of a millimeter or better.
Various frameless stereotactic procedures have been developed which take advantage of the three-dimensional image data of the patient. These procedures include guidedneedle biopsies, shunt placements, craniotomies for lesion or tumor resection, and the like. Another area of frameless stereotaxy procedure which requires extreme accuracy is spinal surgery, including screw fixation, fracture decompression, and spinal tumor removal.
In spinal screw fixation procedures, for example, surgeons or other medical personnel drill and tap a hole in spinal vertebra into which the screw is to be placed. The surgeon relies heavily on his own skill in placing and orienting the bit of the surgical drill prior to forming the hole in the vertebra. Success depends largely upon the surgeon's estimation of anatomical location and orientation in the operative field. This approach has led to suboptimal placement of screws that may injure nerves, blood vessels, or the spinal cord.
The present invention provides a new and improved technique which overcomes the above-referenced problems and others.
SUMMARY OF THE INVENTION
According to one aspect of the present application, a stereotaxic wand is provided. The wand has a tip portion, a portion extending along a pointing axis of the wand, an offset portion which is offset from the pointing axis of the wand, and at least three wand emitters. The three wand emitters selectively emit wand signals which are received by at least two receivers positioned on a frame assembly. The frame assembly mounts the receivers in a fixed relationship to a subject support closely adjacent a means for securing a portion of the patient to the subject support. A wand position determining means determines a position of the wand tip portion from the intersection of the emitter signals between the wand emitters and the two receivers mounted on the frame. A tool guide defines a bore extending longitudinally therethrough along a guide axis. The bore is configured for selectively receiving either a tool or the tip portion of the wand.
According to another aspect of the present application, the tool guide includes teeth on one end to inhibit the guide from slipping on bone.
One advantage of the present application is that it facilitates more accurate surgical procedures.
Another advantage of the present invention is that it promotes patient safety. 5 Still further advantages of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description of the preferred embodiments.
io BRIEF DESCRIPTION OF THE DRAWINGS
The invention may take form in various components and arrangements of components, and in various steps and arrangements of steps. The drawings are only for purposes 15 of illustrating a preferred embodiment and are not to be construed as limiting the invention.
FIG. 1A is a perspective view of an operating room in which the present invention is deployed; FIG. IB is a block diagram of the image data manipula20 tion of the system of FIG. 1A;
FIGS. 2A, 2B, 2C, 2D, 2E, and 2F illustrate alternate embodiments of the wand and guide; FIGS. 3A and 3B are diagrammatic illustrations of the 25 wand and locator relationship;
FIGS. 3C is a flow diagram of the wand location procedure;
FIGS. 4A, 4B, 4C, and 4D are illustrative of a preferred coordinate transform between the coordinate system of the 30 data and the patient.
DETAILED DESCRIPTION OF THE
With reference to FIG. 1A, a subject, such as a human
35 patient, is received on an operating table or other subject support 10 and appropriately positioned within the operating room. A frame 12 is mounted in a fixed relationship to the patient such that it is precisely positioned within the subject or subject support coordinate system. In the illustrated
40 embodiment, the frame 12 is mounted to the patient support 10. Mounting the frame 12 to the patient support permits the patient support to be turned, raised, lowered, wheeled to another location, or the like, without altering the patient coordinate system. Alternately, the support may be mounted
45 to a pole or other stationary support, the ceiling of the room, or the like. The frame 12 supports a plurality of receivers 14 such as charge-coupled device (CCD) arrays, infra-red cameras, light sensitive diodes, other light sensitive receivers, and the like mounted at fixed, known locations
50 thereon. Alternately, the receivers can receive other types of radiant energy such as ultrasound, X-rays, radiation, radio, magnetics, or the like. A securing means such as a head clamp 16, securely positions a portion of the subject under consideration. The frame is mounted at a fixed or selectable
55 angle from vertical such that the frame is positionable more toward the patient, yet still focusing on the region of interest of the patient.
With continuing reference to FIG. 1A and further reference to FIG. IB, an operator console 18 houses a computer
60 system 20. Alternately, the computer system can be remotely located and connected with the control console 18 by cabling. The computer system includes a three-dimensional data memory 22. The stored three-dimensional image data preferably contains a video pixel value for each pixel or
65 point in a three-dimensional rectangular grid of points, preferably a 256x256x256grid. When each image value represents one millimeter cube, the image data represents