Remote actuation of trajectory guide

Claims

What is claimed is:

1. A surgical device comprising:

a base unit;

a ball having a passage therein, said ball fitting within the base unit, said ball capable of rotating with respect to the base unit;

a positioning stem connected to said ball, said positioning stem having proximal and distal ends and having a locator attached to said positioning stem, said locator having two portions in spaced relation with respect to each other, each said locator portion comprising a component which provides a distinctly readable reference point when read using a scanning device;

whereby both said reference points are provided for use as inputs to a computer device functionally attached to said scanning device, said inputs used to calculate a trajectory for guiding a surgical instrument to a target site in a patient;

a platform; and

a locking member which engages the ball and fixes the position of the ball and positioning stem upon tightening the locking member when the ball is properly positioned.

2. The surgical device of claim 1, wherein said locator on said positioning stem includes light emitting diodes.

3. The surgical device of claim 1, wherein said locator on said positioning stem includes a cavity which carries a liquid which is visible to a nuclear magnetic resonance imaging system.

4. The surgical device of claim 1, wherein said locator on said positioning stem includes at least one radiofrequency coil.

5. The surgical device of claim 1, wherein said platform further comprises a stage which is movable in a plane of the platform.

6. The surgical device of claim 1 further comprising a guide stem, said guide stem having an opening therein and attached to said surgical device such that the opening in the guide stem substantially aligns with the passage in the ball.

7. The surgical device of claim 6 wherein the positioning stem fits within the opening of the guide stem.

8. The surgical device of claim 7 wherein the locator is readable by an imaging apparatus.

9. The surgical device of claim 7 further comprising an actuator attached to said guide stem, said actuator used to move the guide stem and ball having a passage therein.

10. The surgical device of claim 6 further comprising;

a suspension tube attached to said base unit; and

a stage attached to said suspension tube, said stage moving the ball with the opening therein in a plane transverse to the opening in the guide stem and the passage in the ball.

11. The surgical device of claim 6 further comprising an actuating system for positioning the guide stem and ball.

12. The surgical device of claim 6 further comprising an actuating system for moving an instrument through the opening in the guide stem and through the passage in the ball.

13. The surgical device of claim 1, wherein said scanning device detects infrared energy.

14. The surgical device of claim 1, wherein said locator on said positioning stem includes an energy emitting device.

15. An apparatus comprising:

a base;

a movable member movably attached to said base and having a passage therein;

a locking member for fixing the position of the movable member; and

a positioning stem further comprising:

a first locator; and

a second locator, said first locator associated with a first position of said positioning stem and said second locator associated with a second portion of said positioning stem, said positioning stem removably attached to said movable member and used to position the movable member and the passage therein, wherein each of the first and second locators comprise a component which provides a distinctly readable reference point when read using a scanning device;

whereby both said reference points are provided for use as inputs to a computer device functionally attached to said scanning device, said inputs used to calculate a trajectory for guiding a surgical instrument to a target site in a patient.

16. The apparatus of claim 15 wherein said first and second locators are readable by a body scanning mechanism.

17. The apparatus of claim 16 wherein said first and second locators are readable by a magnetic resonance imaging apparatus.

18. The apparatus of claim 17 wherein at least one of said first locator and said second locator includes a fluid readable by a magnetic resonance imaging apparatus.

19. The apparatus of claim 17 wherein at least one of said first locator and said second locator includes a radio frequence coil which is readable by a magnetic resonance imaging apparatus.

20. The apparatus of claim 19 wherein said source of radio frequency which is readable by a magnetic resonance imaging apparatus includes at least one or more radiofrequency coils.

21. The apparatus of claim 19 wherein said first and second locators are offset with respect to a centerline of the passage in said movable member.

22. The apparatus of claim 15 wherein said first and second locators are substantially aligned with the centerline of the passage in said movable member.

23. The apparatus of claim 15 wherein said first and second locators are offset with respect to the centerline of passage in said movable member.

24. The apparatus of claim 15 further comprising a guide stem, said guide stem having an opening therein and attached to said movable member such that the opening in the guide stem substantially aligns with the passage in the movable member.

25. The apparatus of claim 24 wherein said positioning stem is interchangeable with said guide stem.

26. The apparatus of claim 24 wherein said positioning stem fits within the opening in said guide stem.

27. The apparatus of claim 26 further comprising a first actuator system for positioning the guide stem.

28. The apparatus of claim 27 wherein said passage in said movable member and said opening in said guide stem form a trajectory, said first actuator system moving the positioning (and/or guide) stem to a position where the trajectory is substantially aligned with a target area within the patient.

29. The apparatus of claim 27 wherein said passage in said movable member and said opening in said guide stem form a trajectory, said first actuator system moving the guide stem to a position where the trajectory is substantially aligned with a target area within the patient.

30. The apparatus of claim 27 further comprising a second actuator system for moving an instrument throught the opening in the guide stem.

31. The apparatus of claim 15 wherein the base, the movable member, the positioning stem, and the locking member are made out of materials useable within a magnetic resonance imaging environment.

32. The apparatus of claim 15 wherein at least one of said first second-locators includes a light emitting diode.

33. The apparatus of claim 15 further comprising a stage attached to the base, said stage defining a plane which intersects a centerline of the passage in the movable member.

34. The apparatus of claim 15 further comprising a cap and plug for sealing an opening in the base.

35. A method for determining a trajectory for an instrument through a guiding device for use with a scanning device, said scanning device including a central processing unit and a memory, said method comprising the steps of:

selecting a target within a patient;

attaching a positioning stem to a movable member carried by the guiding device, the movable member having a passage therein, said positioning stem having a first portion readable by the scanning device and a second portion readable by the scanning device;

determining the position of the first and second portions of the positioning stem;

determining if the passage in the movable member is substantially aligned with the target within the patient based on the position of the first and second portions of the positioning stem.

36. The method for determining a trajectory for an instrument of claim 35 further comprising the step of locking the movable member when the passage within the movable member is substantially aligned with the target within the patient.

37. The method for determining a trajectory for an instrument of claim 35 further comprising the steps of:

removing the positioning stem from the movable member; and

attaching a guide stem to the movable member, said guide stem having an opening therein, said opening in the guide stem substantially aligned with the passage in the movable member when the guide stem is attached to the movable member.

38. The method for determining a trajectory for an instrument of claim 35 further comprising the steps of:

removing the positioning stem from the movable member, said movable member including a guide stem attached to the movable member, said guide stem having an opening therein, said opening in the guide stem substantially aligned with the passage in the movable member, said step of removing the positioning stem including removing the positioning stem from the guide stem.

39. The method for determining a trajectory for an instrument of claim 35 wherein the step of determining the position of the first and second portions of the positioning stem is performed at least in part by the central processing unit and the memory of the scanning device.

40. The method for determining a trajectory for an instrument of claim 35 wherein the step of determining if the passage in the movable member is substantially aligned with the target within the patient is performed at least in part by the central processing unit and the memory of the scanning device.

41. The method for determining a trajectory for an instrument of claim 35 further comprising the steps of:

providing a stage which defines a plane which intersects the centerline of the opening in the movable member; and

moving the stage in the plane to define a trajectory which is substantially parallel to the initially determined trajectory.

42. The method for determining a trajectory for an instrument of claim 35 further comprising the steps of:

providing a stage which defines a plane which intersects a centerline of the opening in the movable member, said stage including the movable member; and

moving the stage in the plane to define a trajectory which is substantially parallel to the initially determined trajectory.

43. The method for determining a trajectory for an instrument of claim 35 further comprising the step of repositioning the first and second locators on the positioning stem using an actuator system.

FIELD OF THE INVENTION

The present invention is related to surgical working platforms. More specifically, the present invention relates to a working platform and method for using the same which facilitates the alignment of surgical and observational instruments into a patient.

BACKGROUND OF THE INVENTION

In the treatment of some diseases or defects associated with a patient, it has been found necessary to access specific targets within a patient. In the treatment of some diseases of or defects of human beings, it has been found necessary to access specific portions of the brain. Currently there are several methods for inserting surgical and observational instruments into a patient's brain.

U.S. Pat. No. 3,055,370 issued to McKinney et al. shows one currently used method for placing a surgical instrument to access a specific portion of the brain. The surgical instrument of the '370 patent includes a ball which has a bore. The direction of the bore can be changed. The instrument has an elongated tube of a specific length. A stylet is inserted within the tube to access the globus pallidus and perform a pallidotomy. An opening or burr hole is made in the skull at a specific landmark on the skull. Next, X-rays are taken in the fore-and-aft (AP) and lateral positions, and the line of the bar is projected downwardly by a ruler both in the fore-and-aft (AP) and lateral positions, so that the direction of the needle can be determined before it is inserted. When the direction of the longitudinal axis of the tubular member is determined to be satisfactory, a holder is threaded further into a tap to force a surface against a ball and lock a tubular member into place. Alignment of the trajectory is not measurable along a specific line occurring at the intersection of two planes. Alignment is dependent on placement of the burr hole at a specific location to determine one plane. X-rays are used to determine another plane-based use of common landmarks on the skull. The end result is that an educated guess is being used to position the stylet at the globus pallidus for the pallidotomy. One shortcoming with the method of using X-ray imaging to direct a surgical or observational instrument, is that many of the destinations within a patient are not viewable via X-ray. Another shortcoming relates to the slight shifting of intracranial contents, once a burr hole is placed and the dura and arachnoid are penetrated. Once cerebrospinal fluid is released via the burr hole, the intracranial contents (i.e. brain) may shift one or more millimeters. In such a case, the calculated trajectory is no longer accurate. Hence, there is an inherent inaccuracy with the described scheme.

Several other methods are also used to place instruments, catheters, or observational tools into patients. Currently, surgical procedures are performed through craniotomy flaps or craniotomy burr holes. A burr hole of about 14 mm is made in the skull. Needles or probes are typically passed through the burr hole into the brain using framed stereotaxy, frameless stereotaxy or freehand without stereotaxy.

The freehand method depends very heavily on the knowledge and judgment of the surgeon. In the freehand method, the surgeon determines the insertion point with a couple of measurements from a known landmark The surgeon then looks at the measured point, makes adjustments, determines the angle of insertion and then inserts the surgical instrument or tool.

In framed stereotaxy, a ring frame is mounted to the patient's skull by multiple (typically three or four) pins or screws. This ring frame is used to determine a three dimensional data set. From this data set, Cartesian coordinates are calculated for both the lesion, the location of the pins or screws, and the fiducial marks on the frame. The ring frame fits into a large frame. A large frame is then attached to the patient in the operating suite. The large frame provides known positions and guides the surgical or observational instruments. The large frame is used to position the instrument to be introduced into the patient through a burr hole so that it intersects the target. In frameless stereotaxy, the ring frame is replaced with several markings on the patient's skull which can be used to determine several known positions. The large frame is replaced by a camera. The camera is usually infrared or some such device. Multiple sensors readable by the camera are placed on the instrument. For example, the surgical instrument or tool is provided with one or more light emitting diodes ("LEDs") which are tracked by the camera. The position of the surgical instrument can be calculated from the information from the LEDs on the surgical instrument or observational tool.

U.S. Pat. No. 4,955,891 and U.S. Pat. No. 4,805,615, both issued to Carol, each discuss the use of stereotaxy surgery with computerized tomographic ("CT") scanning. CT scanning is used to determine the exact position of a lesion or specific portion of the brain. After the exact position of the lesion or specific portion of the brain is determined, a phantom fixture is set up. The phantom fixture replicates the position of the ring frame on the patient. A phantom target is set up. The instrument can then be positioned on the phantom such that it intersects the target. The information from the phantom can then be used in actually positioning the instrument in the operating suite.

U.S. Pat. No. 4,998,938 issued to Ghajar et al. shows another surgical device for facilitating the insertion of an instrument into a patient's cranial cavity through a burr hole. The device includes a guide having an end configured to pass into the burr hole. There is a separate locking member. A body member includes alignment markings to help with insertion of a catheter or stylet. Unlike the '370 patent, there is no movable member for adjusting the path of the guide.

The methods currently in use all have a number of shortcomings. Most of the techniques currently used to place a surgical instrument or observational tool within a patient employ a limited amount of accuracy. In particular, current framed, frameless, and freehand methods compute or predict trajectories on the basis of imaging data or anatomic landmarks that do not account for the slight, but real shifting of the brain upon opening the cranium and meninges to the level of the subarachnoid space. This inherent inaccuracy inherently limits the success of these various methodologies. In other words, these systems do not use any means of updating the data files to include data obtained following the placement of a surgical burr hole and opening of the meninges. In addition, all the methods require large amounts of judgment on the part of the surgeon placing the surgical instrument or tool, and in particular, offer no direct feedback on the success or failure of the trajectory to reach the target. Very few of the techniques use an imaging or scanning apparatus to aid in the placement of the surgical instrument or observational tool. The only one that does requires a phantom frame and target to be set up to simulate the real geometry. In short, none of the apparatuses appear to use an imaging or scanning apparatus as extensively as they could be used to minimize the time and effort needed to accurately place a surgical instrument into a patient, and to offer immediate data on the success or failure of the trajectory to reach the target.

Still another disadvantage is that the apparatuses used today are not remotely controlled or actuated. In some operating environments, the patient is not accessible to the surgeon. Therefore, it is advantageous to have remote control of the tool. One such environment is within an MR magnet associated with an MR operating suite. When the patient is in an open magnet, the surgeon may have direct access to the patient. When in a closed magnet, the surgeon probably will not have such direct access to the patient.

SUMMARY OF THE INVENTION

A surgical method and apparatus for accurately aligning the trajectory of, guiding of, and introducing or withdrawal of an instrument is disclosed. The apparatus includes a base which has a movable member movably attached to the base. The movable member has a passage therein which forms a portion of the trajectory path. The movable member also includes a guide stem which has an opening therein. The guide stem is attached to said movable member such that the opening in the guide stem substantially aligns with the passage in the movable member. The movable member can include either an integral guide stem for holding the positioning stem or a removably attached guide stem. In the case of the former, a positioning stem is inserted into the opening of the guide stem for purposes of trajectory alignment. In the case of the latter, the removably attached guide stem can be removed and replaced with a positioning stem.

A positioning stem further includes a first locator and a second locator. The first and second locators are associated with two different portions of the positioning stem so that they are essentially two points on a line. The first and second locators are also locatable by