HK40012899A - Rotary oscillating surgical tool - Google Patents

Description

Rotary vibration surgical tool

Technical Field

The present invention relates to a vibrating rotary tool having a cutter adapted to modify tissue such as bone, cartilage and intervertebral discs.

Background

The prior art provides surgical tools having rotary cutters adapted to modify tissue, such as bone, cartilage and intervertebral discs, within a patient. However, such tools present problems if the cutter encounters fibrous tissue, such as muscle and nerves. Such fibrous tissue may wrap around the cutter and thus be damaged. The prior art also provides vibrating rotary tools for such surgical procedures, but the mechanisms for effecting cutter vibration during cutting do not operate smoothly due to the mechanisms for effecting vibration. An advance of such a vibrating tool is represented by our co-pending application, No. 13/469,665, filed on 11/5/2012 in the name of pitter L knoop.

Disclosure of Invention

According to one embodiment of the present invention, a surgical tool is provided with a housing, a cutter support shaft operatively connected to a motor to effect rotation of the shaft, and a drive transmission configured between the motor and the shaft to effect oscillating rotational movement of the shaft and cutter.

It is therefore an object of the present invention to provide a vibratory-action-driven transmission that is operatively connected to a motor using a planetary gear set wherein the ring gear of the planetary gear set is fixed against rotation.

It is a further object of the present invention to provide a vibratory-action drive transmission that utilizes the planet gears of a planetary gear set coupled to an engine through an input crank such that the planet gears rotate about the axis of rotation of a motor output shaft located within a ring gear.

It is another object of the present invention to provide a vibratory-action-driven transmission such that a planetary gear set and an input crank are operatively coupled to an output drive connected to the planetary gears of the planetary gear set, wherein a portion of the planetary gears have a substantially linear path of motion forming a Cardan (Cardan) mechanism.

It is a further object of the present invention to provide a universal mechanism that is operatively coupled to the cutter shaft by a motion translation mechanism that includes an output drive coupled to a pivotally mounted follower, the output drive having a gear segment operable to engage a second pinion gear connected to the shaft to drive the cutter.

Other objects and advantages of the present invention will become apparent from the following description taken in conjunction with any accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of the present invention. Any drawings contained herein form a part of the specification, include exemplary embodiments of the present invention, and illustrate various objects and features thereof.

Drawings

FIG. 1 is a perspective view of a surgical tissue removal tool;

FIG. 2 is a cutaway perspective view of the surgical tool of FIG. 1;

FIG. 3 is a partial perspective view of a detail of the internal components of the surgical tool shown in FIG. 1;

FIG. 4 is an enlarged partial perspective view of the transmission portion of the surgical tool of FIG. 1 with some components broken away to show detail;

FIG. 5 is a view similar to FIG. 4, showing portions of the transmission in a first rotational position;

FIG. 6 is a view similar to FIG. 5, showing portions of the transmission in a second rotational position;

FIG. 7 is a view similar to FIG. 4, showing portions of the transmission in a third rotational position;

FIG. 8 is a view similar to FIG. 4, showing portions of the transmission in a fourth rotational position; and

FIG. 9 is a view similar to FIG. 4, showing portions of the transmission in a fifth rotational position.

Detailed Description

Reference numeral 30 generally designates a rotary vibration surgical tool, which is particularly useful for modifying or removing hard tissues such as bone, cartilage and intervertebral disc tissues. The surgical tool 30 is a hand-held tool having a housing 32, the housing 32 being provided with a handle 34 for manually holding the tool 30 for use during surgery. Although one shape and style of handle 34 is shown, any suitable handle shape and style may be provided. For example, a right angle pistol grip may be added. In addition, the housing may have a narrow front for a smaller pencil-like "precision grip" while a larger remainder is sized to balance in the user's hand, such as in the web area between the index finger and thumb to allow for better control, reducing fatigue.

The tool 30 may be used in procedures such as spinal surgery, where tissue, preferably of a non-fibrous tissue type, such as bone, cartilage and intervertebral disc material, may be altered or removed, such as from a patient's spine. The tool 30 has an output shaft 36, the output shaft 36 being driven to rotate in an oscillating manner in two alternating directions about the longitudinal axis 35 of the shaft 36. The shaft 36 is provided with a cutting tool or cutter 38, the position of which cutting tool or cutter 38 is fixed to the distal end portion of the shaft 36. Cutter 38 is driven, as is shaft 36, to rotate in alternate directions with a limited range of rotational angular displacement. Such vibratory rotation has been found to be effective in cutting or modifying hard tissue such as portions of bone, cartilage and intervertebral discs. It has also been found that such vibrational rotation reduces the risk of damage to fibrous tissue such as muscles and nerves.

The tool 30 may receive energy for its operation from an external power source, such as a dc power cord 40. A power control switch 42 may be provided on the housing 32 for controlling operation of the tool 30, such as in an on and off manner and/or in a variable speed manner. A light source 44 may also be disposed on the housing 32 for illuminating the surgical site. Such light sources may be Light Emitting Diodes (LEDs) that may be powered directly or indirectly by energy from the wires 40.

Fig. 2 shows the internal components of the tool 30. The energy source may be provided by a battery power source 46 mounted in the housing 32. The battery power source 46 may be charged by the power cord 40. Electronics 48 are provided in the housing 32 for controlling operation of the tool 30. The power switch 42 may alternatively be located at the distal end of the housing, opposite the position shown at the middle portion of the housing 32. A plurality of indicator lights 50 may also be provided on the housing 32 and may be LEDs for indicating operating characteristics of the tool 30, such as the charge status of the battery power source 46. Alternatively, the battery 46 may be eliminated, facilitating connection of the electrical cord 40 to a source of electrical energy. Additionally, the motor 52 may be powered by compressed air, vacuum, or any other suitable energy source that will effect rotation of the rotor portion of the motor 52 as desired.

The motor 52 is suitably mounted in the housing 32, wherein a portion of the motor, i.e., the rotor, is free to rotate and ultimately drive the shaft 36. A portion of the motor 52 is fixed against rotation within a housing 32, such as a motor housing and/or stator, as is known in the art. The motor 52 drives the shaft 36 through a transmission 54, the transmission 54 being operable for converting continuous rotational motion from the motor 52 into rotational vibration of the shaft 36. The shaft 36 is suitably mounted in a nose 57 of the housing 32, as in a bearing 59. The shaft 36 may be angled relative to the longitudinal axis of the housing 32, as shown in fig. 2, for ergonomics. Cooling fins or cooling fans, not shown, may be attached to or near the motor 52 for cooling the motor and/or the tool 30.

3-9, a transmission 54 is located in the housing 32 and operatively couples the shaft 36 to the motor 52 and is operable to convert continuous rotary motion of an output shaft 60 of the motor 52 into oscillating rotary motion of the shaft 36. By rotational movement, it is meant that the shaft 36 will rotate a portion of a full revolution, first in one rotational direction, then in another rotational direction, e.g., first counterclockwise, then clockwise, then counterclockwise, and so on. To achieve this movement, the transmission 54 includes two parts. A first portion is generally indicated at 61 and is operable to convert the rotary motion of the shaft 60 of the motor 52 into a generally linear reciprocating motion of a portion thereof, and a second portion is generally indicated at 62 and is operable to convert the generally linear reciprocating motion into an oscillating rotary motion.

In the illustrated embodiment, the transmission portion 61 takes the form of a universal mechanism that utilizes an internally-toothed ring gear 64 and externally-toothed planet gears 65, with the planet gears 65 being located internally thereof and having their external gear teeth engaged with the internal gear teeth of the ring gear 64. The gear ratio of the ring gear 64 to the planet gears 65 is 2: 1. the ring gear 64 is suitably secured within the housing 32 to prevent movement thereof relative to the housing 32. The planet gears 65 are suitably mounted to crank arms 66, which crank arms 66 are in turn fixed to the shaft 60 of the motor 52 and offset from the axis of rotation of the shaft 60, so that the planet gears 65 rotate about the axis of rotation of the shaft 60 inside the ring gear 64. Preferably, the crank arm 66 has a counterweight 67, the counterweight 67 being opposite the position where the planetary gear 65 is mounted to the crank arm 66. In a universal mechanism, a tip on a planet gear will move substantially linearly in a reciprocating manner within its associated ring gear. In the illustrated embodiment, oriented as shown in fig. 4, the path of movement of the toe is timed to move in a generally transverse plane relative to the portion of the first portion 61 of the transmission 54. Preferably, fixed to the planet gears 65, in a unitary manner, are drive arms 69 which extend in front of the ring gear 64 for being housed in the followers 70, so as to enable the movement of the followers 70 in response to the movement of the arms 69. Follower 70 is suitably mounted in housing 32 in a manner that allows pivotal movement thereof about axis 71. The transverse linear motion of the point on the planet gear 65 is generally transverse to the longitudinal axis of the elongated slot 74 in the follower 70. Shaft 71 is suitably mounted in bearing support 73, and bearing support 73 is in turn suitably mounted to housing 32. Although only one bearing support 73 is shown, it is preferred that each end of shaft 71 have a bearing support 73 associated therewith. It should be appreciated that shaft 71 may utilize follower 70 as a bearing for rotation of follower 70 about shaft 71, with shaft 71 being fixedly mounted to housing 32. The drive arm 69 is received within an elongated slot 74 for effecting movement of the follower 70 in a rotational oscillating manner. Follower 70 moves in oscillating rotation about the axis of shaft 71. As a portion of the drive arm 69 moves along its linear path, portions of the arm 69 engage the sides of the slot 74 to effect movement of the follower 70 in response to movement of the drive arm 69. This movement can be seen in the various orientations shown in fig. 5-9. In the illustrated construction, the driver 69 is offset to the outside of the outer diameter of the planetary gear 65 so that its central axis does not move in a straight path, but rather in a series of arcs elongated in the horizontal direction and decreasing in the vertical direction as shown by the orientation of the tool 30 in fig. 2. This back and forth and up and down movement is accommodated by configuring the slot 74 to be elongated, as best shown in fig. 4. As driver 69 moves in its path, it affects the oscillating rotational movement of follower 70 about axis 71. Two counterclockwise and two clockwise oscillations of cutter 38 are achieved and four elliptical paths of a portion of driver 69 are traversed for each rotation of planet gear 65 in ring gear 64. The follower 70 is provided with a drive gear, such as a sector gear 76, which is operatively coupled to a driven gear member 77 secured to the shaft 36. As follower 70 moves, shaft 36 responds to it by engagement between gears 76 and 77. Because follower 70 moves in a rotationally oscillating manner, shaft 36 also moves in a rotationally oscillating manner. The components of the transmission portions 61, 62 are configured relative to each other such that when the rotational vibratory motion changes direction at the shaft 36, the torque applied by the motor 52 will be high; when in the center of one vibration, the torque applied by the motor 52 will be lower. This helps provide a high starting torque for cutter 38 to reverse rotational direction.

All patents and publications mentioned in the specification are indicative of the levels of those skilled in the art to which the invention pertains. All patents and publications are herein incorporated by reference to the same extent as if each individual publication was specifically and individually indicated to be incorporated by reference.

It is to be understood that while a certain form of the invention is shown, the invention is not limited to the specific form or arrangement of parts herein described and illustrated. It will be apparent to those skilled in the art that various changes may be made without departing from the scope of the invention and the invention is not to be considered limited to what is shown and described in the specification.

Those skilled in the art will readily appreciate that the present invention is well adapted to carry out the objects and obtain the ends and advantages mentioned, as well as those inherent therein. Any compounds, methods, procedures and techniques described herein are presently representative of the preferred embodiments, are intended to be exemplary, and are not intended as limitations on the scope. Variations thereof and other uses will occur to those skilled in the art, which are encompassed within the spirit of the invention and are defined by the scope of the appended claims. Although the present invention has been described in connection with the specified preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the invention which are obvious to those skilled in the art are intended to be within the scope of the following claims.

Claims (10)

1. A vibrating rotary surgical tool, comprising:

a housing forming a handle;

a motor mounted in a housing, the motor having a rotary output first shaft;

a second shaft rotatably carried by the housing and having a cutter at a distal end of the shaft;

a transmission mounted in the housing and operatively associated with the motor and coupling the first shaft to the second shaft, the transmission having a first portion and a second portion, wherein the first portion includes a planetary gear set including a ring gear fixed against rotation relative to the housing and including first planet gears coupled to the motor for movement within the ring gear about the first shaft, the first portion further including a driver mounted to the first planet gears and movable therewith, the second portion including a follower operatively associated with the driver, the follower being pivotably mounted in the housing and movable in an oscillating manner in response to movement of the driver effected by rotation of the first shaft, the follower includes a drive gear that is also rotationally vibrationally movable, the drive gear engaging a driven gear member fixed to the second shaft such that the second shaft is rotationally vibrationally movable by rotation of the first shaft.

2. The surgical tool of claim 1, wherein a gear ratio of the ring gear to the first planet gears is 2: 1.

3. The surgical tool of claim 2, wherein the first planetary gear is coupled to the first shaft by a crank arm.

4. The surgical tool of claim 3, wherein said follower is operable for reciprocating rotational oscillatory mode motion about a shaft to which it is pivotally mounted.

5. The surgical tool of claim 4, wherein the drive gear is a sector gear that moves arcuately in reciprocating rotational vibration about an axis.

6. The surgical tool of claim 5, wherein the second shaft has a driven gear member secured thereto and is coupled to a sector gear such that reciprocating rotational vibration of the sector gear effects reciprocating rotational vibration of the driven gear member and the second shaft.

7. The surgical tool of claim 6, wherein the second shaft includes a cutter at a distal end thereof and movable with the second shaft in a reciprocating rotational vibration manner.

8. The surgical tool of claim 7, wherein the motor is an electric motor.

9. The surgical tool of claim 8, comprising a power source carried in the housing, the power source comprising at least one battery.

10. The surgical tool of claim 4, wherein the follower includes an elongated slot, wherein a portion of the driver is received in the elongated slot.