JP4598199B2 - Neurosurgical screw kit and electric drill used therefor - Google Patents

Description

  The present invention relates to a neurosurgical screw kit in which a screw for fixing a joint plate that joins a bone flap and a skull is locked to a driver bit in a pre-centered state and is assembled and set to a main body. The present invention relates to an electric drill for tightening the screws of the screw kit.

  A method has been adopted in which the skull is opened by neurosurgery or the like, the opening is closed using a bone valve cut out after the operation or an artificial skull valve, and the opening is fixed to the surrounding skull. In this case, the joining plate is straddled from the outside to the bone flap and the skull, and is fixed by screwing with a tapping screw or driving a nail with a retaining projection called Harken. This type of fixing method is disclosed in, for example, cited references 1 to 4.

  By the way, although the screw which fixes the said joining plate uses the product made from a titanium alloy excellent in biocompatibility, since it is a difficult-to-cut material and processing is difficult, a product will become expensive. Moreover, since it is very small, about 2 mm in diameter and about 4 mm in length, the handling is difficult. Although depending on the case, normal brain surgery is often performed for a long time, and the number of screws used to close the head is as large as 8-20. Of course, the burden on the surgeon at the final stage of the long-term treatment is significant, as well as the burden on the patient.

Japanese Patent Laid-Open No. 9-206311 JP 2000-135220 A JP 2002-45367 A JP 2003-126107 A

An object of the present invention is to provide a neurosurgical screw kit that can be prepared by previously locking a screw head and a driver bit to which a joining plate is attached.
Another purpose is to use a screw kit and use an electric drill for tightening, so that the screw can be screwed in quickly, accurately and easily, shortening the operation time and reducing the burden on both the patient and the operator. It is to provide a dedicated electric drill that can reduce the risk.
Yet another object is to provide a neurosurgical screw kit that can accurately identify the screw used and can easily replenish or manage the screw.

In order to achieve the above object, the neurosurgical screw kit according to the invention of claim 1 is used to fix a bone flap or a prosthetic bone flap and a skull with a joint plate straddling at the time of craniotomy, A screw having a screw thread screwed into the bone flap or skull and a plus groove in the screw head;
A screwdriver bit having a bit fitting portion which is provided with an engaging portion of an annular ridge slightly raised from the peripheral surface on the side surface of the bit shaft, and which is engaged with the plus groove of the screw at the tip of the bit shaft ;
A cylindrical molded body made of a synthetic resin having an inner diameter through which the screw and driver bit shafts are inserted . The cylindrical molded body has an inlet at one end and an outlet at the other end. A locking portion of the annular groove to be stopped is provided , and a main body provided with a flange on the driver bit insertion side,
When the screwdriver bit and the screw are assembled to the main body, the screw bit is fitted into the plus groove of the screw to engage the bit insertion portion, and the screwdriver bit is locked to the main body. It is characterized by.

According to a second aspect of the present invention, in the first aspect, the screw head has a concave portion at the center of the plus groove, and a bit fitting portion that fits into the concave portion projects from the center of the bit fitting portion of the driver bit. It is characterized by being.

The invention of claim 3 is characterized in that, in claim 1, a lot number for identifying a screw is attached to a side surface of the main body.

The invention according to claim 4 is an electric drill used in the neurosurgical screw kit according to claim 1 or 2 , wherein the case main body that fits in one hand has a power supply unit for supplying power and a motor as a drive source. And a planetary gear speed reduction mechanism for reducing the rotational speed of the motor and a fitting portion for a driver bit, an output shaft for transmitting the output rotation from the planetary gear speed reduction mechanism to the driver bit, and the case body itself by the hand. Built-in reverse rotation prevention mechanism that works when rotating and tightening,
The reverse rotation prevention mechanism is provided with a notch having a cam surface with a different depth at an output shaft side end of an internal gear that is rotatably inserted into a case, and a shaft is formed on the cam surface of the notch by a spring. One end of the shaft is pressed, guided by the cam surface of the notch by the rotation of the internal gear, and the other end of the shaft protrudes through a hole in the case end surface on the output shaft side, and is concentric with the rotation output shaft And a lever that rotates synchronously with the internal gear is provided so as to be able to swing between pins fixed at intervals to the case,
When the lever rotates in the forward direction, the shaft is positioned at the deepest cam surface and the shaft end is immersed in the hole of the case. In addition, when further tightening by manual tightening after forward rotation, the shaft is positioned on the shallowest cam surface due to the relative rotation of the internal gear and the case, and the lever contacts the protruding shaft to prevent reverse rotation. It is characterized by.

According to the neurosurgical screw kit of the present invention, a small screw that is difficult to handle is preliminarily locked to the main body in a state where it is centered on the driver bit, so that it is possible to prevent mishandling or dropping from the driver bit. It is possible to prevent a tightening failure caused by a screw being lost or not being centered.

Furthermore, inventory management can be prepared by assigning a lot number to each screw.

According to the combination of the electric drill of the present invention and the neurosurgical screw kit, the operation of attaching the driver bit to the electric drill, the operation of stopping screwing, and the operation of manually tightening after stopping can be performed with one hand. The screw can be screwed quickly, accurately and easily, and the operation time can be shortened, and the burden on both the patient and the operator is reduced.

  In response to the above problems, the present invention incorporates a screwdriver bit and screw into the main body and locks the screwdriver bit to the main body to form a screw kit. It was realized by an electric drill that can be mounted on the shaft and that can be manually tightened by using a reverse rotation prevention mechanism after the electric screw tightening operation.

  1 is a plan view showing an external appearance of an embodiment of a neurosurgical screw kit according to the present invention, FIG. 2 is a plan view showing a screw kit before assembly, FIG. 3 is a sectional view when the screw kit is assembled, FIG. 3A FIG. 2 is a partially enlarged sectional view of a main body.

  The screw kit 1 is composed of three parts, a cylindrical main body 2, a screw 3, and a driver bit 4. A screw 3 for fixing a joint plate 12 (see FIG. 9) for connecting the bone flap and the skull 13 is previously provided. The driver bit 4 is set in the main body 2 in a centered state.

Body 2 is synthesized resins or Ranaru open ends, and having a cylindrical shaped body having an inner diameter screw 3 and the driver bit 4 is inserted, and an outlet 22 to the inlet 21 and the other end to one end. The inlet 21 of the main body 2 is provided with an annular flange 23. Lot number 15 (LOT # ***) of the screw 3 is attached to the outer peripheral surface of the cylinder of the main body 2, so that the screw can be easily specified and managed.

Locking portions 210 and 220 each having an annular groove are provided on the inner edge of the inlet 21 and the inner edge of the outlet 22 of the main body 2. On the side surface of the driver bit 4, there is provided an engaging portion 41 constituted by an annular ridge or the like slightly raised from the peripheral surface. When the driver bit 4 is inserted into the main body 2, the engaging portion 41 of the driver bit 4 gets over the locking portion 210 of the main body 2 to prevent the driver bit 4 from falling off the main body 2.

FIG. 4 is a side sectional view of the screw, FIG. 4A is a front view of the screw head, and FIG. 4B is a side view of the tip portion of the driver bit.
The screw 3 is made of a titanium alloy because of its non-toxicity and biocompatibility that is unmatched by other metals, and is formed into a round tip with a screw head 30 diameter of about 2 mm and a screw thread length of about 4 mm. It is a tapping screw. The screw head 30 is provided with a plus groove 31 that meshes with the plus blade 41 of the driver bit 4, and a circular fitting recess 32 is formed at the center of the plus groove 31.

  The tip of the driver bit 4 is provided with a plus blade 41 that meshes with the plus-type groove, and a projection 42 that is fitted into the fitting recess 32 of the screw 3 at the center of the plus blade 41. In addition, a bit grip portion 43 having a hexagonal cross section is provided at the other end, and is attached to an electric drill 30 described later.

Next, the electric drill will be described.
FIG. 5 is a plan view of the electric drill, and FIG. 6 is a longitudinal sectional view of the electric drill. The electric drill 30 has a motor 32, a speed reducer 33, a rotation output shaft 34, and a stop switch 35 incorporated in a case body 31 that can be held in one hand, a power switch 36 for operating the motor 32, and forward / reverse switching. A switch 37 and a start switch 38 are provided. The motor 32 is supplied with power from the battery 40, and is decelerated to a rotation speed suitable for tightening by the speed reducer 33 and output to the rotation output shaft 34. The grip portion of the case body 31 is provided with a slit 39 for preventing slipping.

  FIG. 7 is a plan view of a case provided with a speed reducer and a reverse rotation prevention mechanism. FIG. 7A shows the relationship between the internal gear and the shaft. (1) Plan view when screw tightening, (2) Hand tightening 7B is a left side view of the case of FIG. 7A, and FIG. 7C is a right side view of the case of FIG. 7A.

  The reduction gear 33 is composed of a planetary gear mechanism, and the sun gear 50 is attached to the rotation shaft 321 of the motor, and is configured to transmit the rotational force from the planetary gear 51 arranged at intervals of 60 degrees to the internal gear 52. The internal gear 52 is rotatably inserted into the case 60. A notch having a cam surface 54 is formed at the end of the internal gear 52 on the rotation output shaft 34 side, and a shaft 56 is disposed so as to be pressed against the cam surface 54 by a spring 55. The other end of the shaft 56 passes through the hole 61 in the end surface of the case 60 on the rotation output shaft 34 side, and protrudes against the elasticity of the spring 55.

When the case 60 rotates forward, the shaft 56 is guided by the cam surface 54 and the shaft 56 protrudes from the hole 61 of the case 60 (FIG. 7A (2)).
A lever 62 that rotates synchronously with the internal gear 52 is concentrically supported by the rotation output shaft 34 and is provided so as to swing between pins 63 and 64 fixed to the case 60.

  During forward rotation of the lever 62, the shaft 56 is positioned at the deepest cam surface (FIG. 7A (1)), and the shaft end is immersed in the hole 61, so that it abuts against the pin 63 and stops (FIG. 8 (1)). At the time of reverse rotation, it abuts on the pin 64 and stops (FIG. 8 (2)). When further tightening is performed by hand tightening after the forward rotation, the shaft 56 is positioned on the shallowest cam surface as shown in FIG. 7A (2) due to the relative rotation of the internal gear 52 and the case 60. The lever 62 abuts against the reverse rotation to prevent reverse rotation (FIG. 8 (3)).

  The sensor unit will be described. In FIG. 6, the sensor unit 7 surrounds the rotation output shaft 34 and is fitted in the case main body 31, and forms a small diameter portion 71 on the distal end side of the case main body 31 and a large diameter portion 72 on the inner side of the case main body 31. As a whole, it is configured as a cylindrical body. The stepped portion 73 of the small diameter portion 71 and the large diameter portion 72 has a flange portion 731 outside the large diameter portion 72, and a spring 74 is disposed between the flange portion 731 and the case body 31, and the sensor portion 7 is always provided. As shown in the figure, the stepped portion 73 is brought into contact with the receiving portion 311 of the case main body 31. At this time, the small diameter portion 71 is kept protruding from the case body 31. The switch knob 351 of the stop switch 35 faces the end surface of the large diameter portion 72, and the stop switch 35 is turned on and off by the movement of the large diameter portion 72.

  The small diameter portion 421 is incorporated so as to be movable in the direction along the rotation output shaft 34, and a part of the small diameter portion 421 protrudes from the tip of the case main body 31. A through hole 72 of the bit head 43 of the driver bit 4 is formed on the end surface of the small diameter portion 421, and the peripheral end surface of the through hole 72 acts on the end surface of the annular flange 23 of the main body 2. At this time, a sufficient gap is provided between the inner surface of the end portion of the small diameter portion 421 and the tip of the rotation output shaft 34 in order to allow the small diameter portion 421 to be pushed toward the case body 31.

Next, the operation of the screw kit and the tightening electric drill will be described.
FIG. 8 shows a procedure for attaching a screw with a driver bit, and FIG. 9 shows a procedure for using the screw with a driver bit.
A plurality of screw kits 1 are accommodated in the screw case 20. The bit head 43 of the driver bit 4 is inserted into the hexagonal recessed hole 341 at the tip of the rotary output shaft 34 and held by friction on the inner wall surface, and then pulled upward and mounted on the electric drill 30.

When performing the screw tightening operation, the forward / reverse switch 37 is set to the forward rotation position, and the power switch 36 is set to the on position. Subsequently, the start switch 38 is operated (FIG. 9 (2)) while the tip of the screw 3 is aligned with the hole of the joining plate 12 (FIG. 9 (1)) and pressed vertically.
When the screw 3 is screwed into the bonding plate 12 to an appropriate position, the sensor unit 7 is pushed, and the motor 32 stops when the stop switch 35 is turned off. At this time, since the final retightening is performed, if the case main body 31 itself is rotated forward by hand, the reverse rotation prevention mechanism works to securely retighten (FIGS. 9 (3) (4)).

It is a top view which shows the external appearance of the Example of the screw kit for neurosurgery which concerns on this invention. It is a top view before the assembly | attachment of a screw kit. It is sectional drawing at the time of the assembly | attachment of a screw kit. It is a partial expanded sectional view of a main part. It is a longitudinal cross-sectional view of a screw. It is a front view of a screw head. It is a side view of the front-end | tip part of a driver bit. It is a top view of an electric drill. It is a longitudinal cross-sectional view of an electric drill. It is a top view of a case provided with a reduction gear and a reverse rotation prevention mechanism. It shows a relationship between an internal gear and a shaft, and is a plan view when (1) screw tightening and (2) additional tightening by hand. It is a left view of the case of FIG. 7A. It is a right view of the case of FIG. 7A. It is a figure which shows the procedure which mounts | wears with a screw with a driver bit. It is a figure which shows the procedure which uses a screw with a driver bit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Screw kit 2 Main body 3 Screw 4 Driver bit 7 Sensor part 12 Joining plate 15 Lot number 20 Screw case with driver bit 30 Electric drill 32 Motor 33 Reducer 34 Rotation output shaft 35 Stop switch

Claims (4)

A screw having a screw thread to be screwed into the bone flap or the skull and a plus groove of the screw head, which is used when the bone plate or the artificial bone flap and the skull are fixed over the joint plate at the time of craniotomy;
A screwdriver bit having a bit fitting portion which is provided with an engaging portion of an annular ridge slightly raised from the peripheral surface on the side surface of the bit shaft, and which is engaged with the plus groove of the screw at the tip of the bit shaft ;
A cylindrical molded body made of a synthetic resin having an inner diameter through which the screw and driver bit shafts are inserted . The cylindrical molded body has an inlet at one end and an outlet at the other end. A locking portion of the annular groove to be stopped is provided , and a main body provided with a flange on the driver bit insertion side,
When the screwdriver bit and the screw are assembled to the main body, the screw bit is fitted into the plus groove of the screw to engage the bit insertion portion, and the screwdriver bit is locked to the main body. A neurosurgical screw kit.   2. The screw head has a recess at the center of a plus groove, and a bit fitting portion that fits into the recess is formed at the center of a bit insertion portion of the driver bit. Neurosurgery screw kit.   The screw kit for neurosurgery according to claim 1, wherein a lot number for identifying a screw is attached to the side surface of the main body. An electric drill used in the neurosurgical screw kit according to claim 1 or 2 ,
The case body that fits in one hand has a power supply unit for supplying power, a motor as a drive source, a planetary gear reduction mechanism for reducing the rotational speed of the motor, and a fitting portion for a driver bit, and the planetary gear reduction mechanism An output shaft that transmits output rotation from the driver bit, a reverse rotation prevention mechanism that works when the case body itself is rotated forward and tightened by hand is incorporated,
The reverse rotation prevention mechanism is provided with a notch having a cam surface with a different depth at an output shaft side end of an internal gear that is rotatably inserted into a case, and a shaft is formed on the cam surface of the notch by a spring. One end of the shaft is pressed, guided by the cam surface of the notch by the rotation of the internal gear, and the other end of the shaft protrudes through a hole in the case end surface on the output shaft side, and is concentric with the rotation output shaft And a lever that rotates synchronously with the internal gear is provided so as to be able to swing between pins fixed at intervals to the case,
When the lever rotates in the forward direction, the shaft is positioned at the deepest cam surface and the shaft end is immersed in the hole of the case. In addition, when further tightening by manual tightening after forward rotation, the shaft is positioned on the shallowest cam surface due to the relative rotation of the internal gear and the case, and the lever contacts the protruding shaft to prevent reverse rotation. Electric drill characterized by

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