WO2000048508A1

WO2000048508A1 - Method and apparatus for securing a reference unit to a patient

Info

Publication number: WO2000048508A1
Application number: PCT/US2000/003988
Authority: WO
Inventors: Thomas Boyajian; Brian Conley; Allan Dennison; Martin Sklar
Original assignee: Visualization Technology, Inc.
Priority date: 1999-02-16
Filing date: 2000-02-16
Publication date: 2000-08-24
Also published as: WO2000048508A9; AU3366300A

Abstract

The invention provides an apparatus for use in a system for monitoring the position of a medical instrument (7). The apparatus is for securing a reference unit to a surgical patient (9), includes a first unit (10, 40) that is adapted to be secured to the bone of a patient (9), and a second unit (26) that is adapted to releasably engage the first unit.

Description

METHOD AND APPARATUS FOR SECURING

A REFERENCE UNIT TO A PATIENT

BACKGROUND OF THE INVENTION The present application claims priority to United States Provisional Patent

Application Ser. No. 60/120,185 filed on February 16, 1999.

The invention relates to the field of system for monitoring the position of the medical instrument and/or a patient during surgery as disclosed, for example, in United States Patent No. 5,873,822, the disclosure of which is hereby incorporated by reference. Such systems may include position monitoring systems such as electromagnetic position detection systems, as well as systems that rely on the speed of transmission of signals, e.g., light or sound, or systems that include cameras, charge couple devices (CCDs), and image processors to monitor the position of an instrument and/or a patient in a surgical environment, such as a hospital operating room. As shown in Figure 1, such systems may include computer 3 that communicates with a display monitor 5, a medical instrument 7 and possibly a reference unit that is adapted to be attached to a patient 9.

In such position monitoring systems, it is generally desirable to continuously identify the position of the tip of a medical instrument as well as the orientation of the instrument itself in the surgical environment. It is also generally desirable to monitor the position and orientation of the patient. Although apparatus have been developed for securing a position detection reference unit, e.g., a transmitter, a sensor, or a reflector etc., to a patient's head as shown in Figure 1 , there is a need for fixedly securing a reference unit to other parts of a patient's body, particularly for surgical applications involving areas other than the head and throat. For such applications, a reference unit may be fastened to the outside of a patient's body, but there is still some risk of movement of the reference unit with respect to the body. There is also a possibility that the skin of a patient may move in the area of the reference unit, which might also affect the integrity of the position monitoring system. It is also desirable, however, that the reference unit be easily removed as necessary, yet accurately repositioned on the body in the same position.

There is a need, therefore, for an apparatus and method for fixedly securing a reference unit to a patient's body in a position monitoring system. There is also a need for such an apparatus and method that is relatively easy to use, permitting a reference unit to be repeatedly repositioned on the body with a high degree of accuracy.

SUMMARY OF THE INVENTION

The invention provides an apparatus for releasably securing a reference unit to a surgical patient in a system for monitoring the position of a medical instrument. The apparatus includes a first unit that is adapted to be secured to the bone of a patient, and a second unit that is adapted to releasably engage the first unit. In certain embodiments, the apparatus includes slots on one of the units for receiving posts on the other of the units.

BRIEF DESCRIPTION OF THE DRAWINGS

The following description of various embodiments of the invention may be further understood with reference to the drawings in which:

FIG. 1 shows an illustrative view of a prior art system for monitoring the position of a medical instrument in a surgical environment; FIG. 2 shows an illustrative view of an apparatus for securing a reference unit to a patient in accordance with an embodiment of the invention;

FIG. 3 shows an illustrative view of the apparatus of FIG. 2 secured to a surgical patient;

FIG. 4 shows an illustrative view of the apparatus of FIG. 3 together with a reference unit housing;

FIG. 5 shows an illustrative side view of the reference unit housing engaging the apparatus of FIG. 4;

FIG. 6 shows an illustrative view of the reference unit housing secured to the apparatus of FIG. 5; FIG. 7 shows an illustrative view of an apparatus for securing a reference unit to a surgical patient in accordance with another embodiment of the invention; and

FIG. 8 shows an illustrative view of the apparatus of FIG. 7 secured to a surgical patient.

The drawings are included for illustrative purposes only, and are not to scale.

DETAILED DESCRIPTION OF THE INVENTION

As shown in Figure 2, an apparatus 10 in accordance with an embodiment of the invention includes an internal shaft pin, one end of which includes a tapered and threaded drill bit portion 12, and the other end of which includes a drive member 14, which is hexagonal in cross section. The drill bit shaft is freely rotatable within a sleeve 16, which includes conical prongs 18. The drill bit portion 12 of the apparatus may be driven into a bone portion 20 of a patient 22 as shown in Figure 3 by rotating the drive member 14 in the

5 direction as generally indicated at A. Because the sleeve 16 is retained by the stop 24 on the shaft pin near the drive member 14, the sleeve is caused to be urged toward the patient as generally indicated at B in Figure 2. When the conical prongs 18 of the sleeve 16 contact the patient, they engage the patient as shown in Figure 3. Since the shaft pin is free to rotate within the sleeve, the conical prongs do not rotate with respect to the patient. Instead, they

10 are urged downward (as shown) through the patient's skin and into a portion of the body such as a bone at the insertion site. The conical prongs preferably contact the same bone into which the drill bit portion 12 of the shaft pin is engaged. The apparatus is thereby secured to the patient.

A reference unit housing 26 may then be releasably attached to the apparatus 10 as

15 shown in Figures 4 - 6. The reference unit housing 26 may include an enclosed or attached transmitter, sensor, or passive reflective device 34 for use in a position monitoring system.

As shown in Figures 2 - 4, the sleeve 16 further includes a biasing spring 28, and retaining posts 30, and the reference unit housing 26 includes a pair of generally "j" shaped slots 32 for receiving the posts 30 on the distal end thereof. As shown in Figure 5, when the housing

20 26 is placed over the apparatus 10, it may be rotated slightly to cause the slots 32 to allign with the posts 30. As shown in Figure 6, if the housing 26 is pushed further downward to compress the spring 28, the housing 26 may then be rotated 45 degrees, and then released thereby securing the housing 26 onto the apparatus via the full engagement of the posts 30 within the slots 32. The reference unit housing 26 may then be easily and repeatedly

25 removed from and refastened to the apparatus with a high degree of accuracy.

As shown in Figures 7 and 8, in accordance with another embodiment of the invention, an attachment apparatus 40 may include a rotatable jaw portion 42 that is adapted to be secured to a portion of a patient's body, e.g., a portion of the spine of a patient against a fixed jaw portion 44. Specifically, the teeth 54 of the jaw portions 42 and 44 may engage

30 the spinous process of a single vertibra of the spine of a patient. The rotatable jaw portion

42 is driven toward the jaw portion 44 via sliding movement of an actuator sleeve 46 in the direction generally indicated at C in Figure 8. The sleeve 46 may be biased in the open position via a leaf spring 48 that is caused to bend upon actuation of the rotatable jaw portion 42.

The apparatus 40 also includes a spring 50, and a pair of retaining posts 52 similar to the spring 28 and posts 30 of the apparatus 10 discussed above. A reference unit housing 26 may be easily and accurately attached to, removed from, and reattached to the apparatus 40 as discussed above in connection with the apparatus 10.

Those skilled in the art will appreciate that modifications and variations may be made to the above disclosed embodiments without departing from the spirit and scope of the invention.

What is claimed is:

Claims

1 In a system for monitoring the position of a medical instrument, an apparatus for securing a reference unit to a surgical patient, said apparatus comprising: a first unit that is adapted to be secured to the bone of a patient; and a second unit that is adapted to releasably engage said first unit.

2. An apparatus as claimed in claim 1 , wherein said first unit further includes a biasing spring and a post onto which a slot in said second unit may be secured.

3. An apparatus as claimed in claim 1, wherein said first unit further includes a screw for securing said firs unit to the bone of the patient.

4. An apparatus as claimed in claim 1 , wherein said first unit further includes at least one prong for engaging the patient.

5. An apparatus as claimed in claim 1, wherein said second unit further includes a position detection unit.

6. An apparatus as claimed in claim 1 , wherein said first unit further includes at least one actuatable jaw for engaging the bone of a patient.

7. An apparatus as claimed in claim 6, wherein said first unit further includes a spring bias element urging the actuatable jaw into an open position.

8. In a system for monitoring the position of a medical instrument, an apparatus for securing a reference unit to a surgical patient, said apparatus comprising: a first unit that is adapted to be secured to the bone of a patient via a threaded screw; and a second unit that is adapted to releasably engage said first unit.

9. In a system for monitoring the position of a medical instrument, an apparatus for securing a reference unit to a surgical patient, said apparatus comprising: a first unit that is adapted to be secured to the bone of a patient via at least one actuatable jaw; and a second unit that is adapted to releasably engage said first unit.

10. An apparatus as claimed in claim 9, wherein said first unit is secured to said second unit.