KR20010033867A - Intramedullary Skeletal Distractor And Method - Google Patents

Abstract

There is provided an elongation device 10 for performing progressive elongation of a cut bone having no extraneous elements, and a method of using the device. The stretching device 10 has a pair of elastically coupled cylindrical members 20,30, which are inserted into the bone marrow space and one cylindrical member 20,30 is attached to each bone cut. Under normal torsion applied by an infected limb, clutch mechanisms 60 and 70 are provided and the clutch mechanism forcibly spaces the cylindrical members 20 and 30 to separate the cuts of bone at the site where new bone growth is promoted. Let's do it. A small rotation of 1 ° is enough to cause elongation. Apparatus for detecting and measuring the amount of extraneous elongation generated is also provided.

Description

Intramedullary Skeletal Distractor And Method

The problem of limb-length mismatches resulting from congenital, infectious and traumatic disorders has attracted the attention of a number of researchers. Various devices are known which are capable of joining and progressively elongating the ends of the cut bone, which causes the bone tissue to grow at the site of the cut and thus to extend the bone in a balanced manner. The device can then be removed or left in place as an internal splint when the desired length is achieved.

External renal devices, which typically include pins passing through soft tissues and bones, can pose a non-negligible potential risk of infection, pain, and muscle building. However, one advantage is the in vitro manipulation accessibility of this type of device.

Various internal devices are disclosed that are designed to be located in the bone marrow of elongated bones. Prior art publications also disclose an intramedullary stretching device.

Attempts have been made to prevent the need for direct contact with elongated members (Grammont et al., US Pat. No. 5,074,882; Trans. 37th Ann. Mtg. Orthopaedic Research Soc., Vol. 16, p.657, 1991). ). In conventional prosthetics, two telescoping tubes are used to promote progressive extension of the limbs. Related embodiments of the apparatus and methods described herein are incorporated herein by reference and include: Justin and J. D. The name of the invention given to J.D. Cole is disclosed in US Pat. No. 5,505,733, "Intraspinal Skeletal Stretch Devices and Methods."

FIELD OF THE INVENTION The present invention relates generally to surgical instruments used for bone elongation, and more particularly to devices and methods for intramedullary skeletal extension.

1A is an assembly view of the skeletal stretching device in its most retracted position;

1B is an exploded view of the skeletal stretching device.

2A is a longitudinal view of a first cylindrical member.

FIG. 2B is a longitudinal sectional view of the first cylindrical member with FIG. 2A rotated 90 ° along the cylindrical axis; FIG.

3A is a longitudinal view of a second cylindrical member.

FIG. 3B is a longitudinal sectional view of the second cylindrical member with FIG. 3A rotated 90 ° along the cylindrical axis; FIG.

4A is a view of an extension rod.

FIG. 4B is a view of the extension rod rotated 90 ° along the cylindrical axis of FIG. 4A; FIG.

5A is a cross-sectional view of an embodiment of a display mechanism in which a piston is located in a cutout;

5B is a cross-sectional view of an embodiment of an indicator mechanism with the piston fully positioned in the bore in the extension rod;

5C is a cross-sectional view of another embodiment of a display mechanism having a pair of pistons.

6 is an exploded view of the over-rotating roller clutch used in the stretching device.

7 is a diagram of a skeletal stretching device located within the spinal cord cavity of the bone.

8 is an illustration of another embodiment of an apparatus having a curved first cylindrical member.

9 is a perspective view of a key ring of the present invention.

10 is an exploded view of a device having a magnetic position indicating device.

11A is a perspective view of a magnetically driven embodiment of a skeletal stretching device using static magnets.

11B is a perspective view of a magnetically driven embodiment of a skeletal stretching device using an electromagnet;

11C is an exploded view of the device.

11D is a cross-sectional view of the second cylindrical member.

12 is a perspective view of a magnetic position indicator positioned in the bone;

13 is a perspective view of an integrated assembly of another roller clutch.

14 is an exploded view of another embodiment of an overrotating roller clutch.

It is an object of the present invention to provide an intra spinal skeletal stretching device which is stretched under the normal forces and torsion experienced in everyday life and thus promotes the progressive stretching of the cut bone.

Another object of the present invention is to provide a device having no extraneous elements.

It is a further object of the present invention to provide an elongation mechanism in which the movement is performed by use of a clutch and a threaded rod, wherein the clutch and the threaded rod together generate elongation in one direction under rotation and in opposite directions under rotation Prevent shrinkage.

It is a further object of the present invention to provide a device having an extension mechanism that is not subjected to axial loads imposed by the weight and tissue of the patient, such as in a construction state.

It is still another object of the present invention to provide an apparatus for emitting an extracorporeal water soluble signal indication of the amount of elongation produced by the elongation mechanism.

These and other objects of the present invention are achieved by an apparatus and method for stretching bone. The device, the intramedullary skeletal stretching device, responds to rotational vibrations during vertical movement in the bone marrow of the bone.

The stretching device of the present invention is used in a bone marrow cavity of bone and includes first and second cylindrical members having dimensions such that the second cylindrical member can slide into the first cylindrical member in a stretchable manner. Each member has a first end, a second end, and a bore, wherein the member is stretched such that the first end of the second member is positioned between the first and second ends of the first member. In use, the first and second cylindrical members are attached to the proximal and distal cuts of the bone, respectively.

The apparatus also includes an extension rod, the extension rod also having a first and second end and having a diameter dimensioned to slide into the bore of the second cylindrical member. The first end of the rod is located in and attached to the bore of the first cylindrical member. The second end of the rod is located in the bore of the second cylindrical member.

In one embodiment, the clutch means is located on the extension rod in the bore of the first cylindrical member. The clutch means selectively responds to rotation in the first direction during operation on the second cylindrical member to effect the stretching movement. During rotation in the opposing second direction, the clutch means locks the rotation of the rod, thus preventing the contracted telescopic movement. The clutch means is located outside of the threaded rod and the axial (longitudinal) kinetic chains of the first and second cylindrical members, thereby preventing the clutch means from receiving an axial load during use. This offers the advantage of allowing good rotational response since the clutch means need not have sufficient strength to withstand this axial load.

In one dependent embodiment, the clutch means comprises a first and a second clutch. The first clutch is located between the first ends of the first and second cylindrical members in the bore of the first cylindrical member. The first clutch has an outer circumference dimensioned to sufficiently airtight fit in the bore such that movement is transmitted between the first cylindrical member and the first clutch. The first clutch is also located on the extension rod, the inner diameter of the first clutch being sufficiently tightly fitted on the extension rod such that movement in the first direction is transmitted thereto and movement in the second direction allows sliding therebetween. Is tailored.

The second clutch is located on the threaded portion of the extension rod in the bore of the second cylindrical member. The second clutch also has an outer periphery dimensioned to sufficiently tight fit in the bore such that movement is transmitted therebetween. If rotation of the extension rod occurs in the second direction, sliding of the extension rod in the second clutch is permitted, the second clutch being transferred along the threaded portion and pushing the second cylindrical member away from the first cylindrical member. If rotation occurs in the first direction, the sliding of the extension rod in the second clutch is not allowed, the extension rod rotates with the second clutch and slides into the first clutch, and no axial movement occurs.

In another embodiment, means are provided for communicating with the stretching rod to determine the amount of stretching generated from the starting position. The crystal can originate from an extradermal site (ie it is non-invasive).

In another embodiment, rotational execution means attached to the extension rod is provided. The means takes the form of a magnetizable material and responds to the extraneous signal to cause rotation. Thus, stretching may be performed non-invasive and controllable from an external location of the device.

The method using the first embodiment of the skeletal stretching device includes the following steps. The device is inserted into the bone marrow of the bone. The first cylindrical member is then attached to the proximal cut of the bone and the second cylindrical member is attached to the distal cut of the bone. Due to the precision of the clutch mechanism as used herein, during normal vertical movement, sufficient torsion is normally generated to actuate the clutch mechanism and to perform stretching. Once enough kidneys have developed in the bone, the device is removed.

The method of using an externally driven skeletal stretching device includes the step of generating a stretch movement between the first and second cylindrical members by rotational rotation of the stretching rod rather than relying on physiological twisting.

Features of the construction and method of operation which characterize the invention will become more apparent from the following description set forth in connection with the accompanying drawings, together with other objects and advantages of the invention. It is to be understood that the drawings are for purposes of illustration and description, and do not limit the invention. These and other objects and advantages provided by the present invention will become more apparent from the following detailed description set forth in conjunction with the accompanying drawings.

A preferred embodiment of the present invention will be described with reference to FIGS. 1A-14.

<First Example>

The intramedullary bone marrow extension apparatus shown in FIG. 1A and FIG. 1B, respectively, is shown by reference numeral 10. The stretching device 10 includes a first cylindrical member 20 and a second cylindrical member 30 shown in cross-section in FIGS. 2A, 2B and 3A, 3B, respectively, and the stretching shown in FIGS. 4A and 4B. The rod 40 and the display mechanism 50 shown in FIG. 5A, 5B, and 5C are included. In this embodiment, the clutch means comprises a first clutch 60 and a second clutch 70 (FIGS. 1A and 1B), wherein the first and second clutch allow rotation in one direction and in the other direction. It is an overrunning roller clutch that locks the movement. It will be apparent to those skilled in the art that other types of clutches such as springs, spiral-bands, friction, magnetism, or sprag clutches can be substituted.

Specifically, the first cylindrical member 20 (FIGS. 2A and 2B) has a first end 202, a second end 204, an outer diameter 206, an inner wall 214, an outer wall 216 and a partial bell. Has a directional bore 208. The bore 208 communicates with the second end 204 but does not extend to the first end 202.

An angled bore 212 is adjacent to the first end 202, through which the screw 604 secures the first cylindrical member 20 to the proximal cut 602 of the bone 60. Inserted (see FIG. 7). Angular bore 212 is not in communication with longitudinal bore 208. In a suitable embodiment, the angle 218 measured from the cylindrical axis of the first end 202 to the axis of the bore 212 is, for example, 45 ° to 60 ° for the femur or humerus. The angle allows the fastening means to engage the thickest part of the bone, thus providing the strongest strength.

In the case of the tibia, a slightly different embodiment is provided than the first cylindrical member 80. As shown in FIG. 8, the first end 802 of the first cylindrical member 80 is typically curved at an angle 810 of about 10 ° from the cylindrical axis. The curved position 804 is generated between the first end 802 and the end of the bore 808 closest to the first end 802. In the present embodiment, instead of the angled bores 212, two diameter bores 806, 808 are provided adjacent the first end 802, through which the pair of screws is provided with the first cylindrical member 80. Can be inserted to secure the proximal cut of the tibia.

Referring again to FIGS. 2A and 2B, a threaded longitudinal bore 210 is located within the first end 202 and in communication with the angular bores 212, but not in communication with the longitudinal bores 208. Threaded bore 210 is used during insertion and withdrawal of the device by screwing an extension member (not shown) into bore 210. The bore 210 is also used as a passage for insertion of the drill guide to assist in the correct placement of the screw 604. In other embodiments, nails may be used in place of screws 604. By screw or nail, bore 210 may also be used for locking set screw 606 to secure the screw or nail in place.

The bore 208 starts with the second end 204, and includes a first zone 220 having a maximum diameter 222 and a length 221, a second zone 224 having a median diameter 226, and It has three zones of a third zone 228 having a minimum diameter 230 and having an octagonal inner wall contour in the axial cross section.

The outer wall 216 has a tapered zone 232 at the second end 204, through which a pair of opposing slots 234, 236 can engage the keyring 95 as described below. Has (238).

The second cylindrical member 30 shown in detail in FIGS. 3A and 3B has a first end 302, a second end 304, an outer diameter 306, a longitudinal bore 308, an outer wall 310 and an inner wall. Has 312. The outer diameter 306 is dimensioned to slidably engage the first zone 220 of the bore 208 in the first cylindrical member 20. The outer diameter 306 is dimensioned to be larger than the diameter 226 of the second zone 224, so that the depth within which the second cylindrical member 30 can be inserted into the first cylindrical member 20 is determined by the first zone. It is determined by the length 221 of 220. Upon assembly (see FIGS. 1A and 1B), the first end 302 is inserted into the bore 208 from the second end 204 of the first cylindrical member 20 (extension rod 40, followed by Reference}. In a suitable embodiment, the second end 304 is tapered 315 and has a rounded edge 313 to facilitate insertion. A pair of opposing slots 314, 316 not in communication with the bore 308 extends from an adjacent second end 304 to a region 318 of the first end 302. Slots 314 and 316 have a width 315 perpendicular to the axis of second cylindrical member 30. A pair of diameter bores 320, 322 extend near the second end 304 and have a diameter greater than the width 315 of the slots 314, 316. Bore 320, 322 is used for screws 607, 608 to secure member 30 to distal cut 610 of bone 60 (see FIG. 7).

Starting from the second end 304, the bore 308 has a first zone 334 having a diameter 326, a second zone 336 threaded with a diameter 338, and a diameter 342. Has three zones of a third zone 340 having.

The distal plug 90 (FIG. 1B) is dimensioned to fit into the bore 308 of the second cylindrical member 30 at the second end 304 and the bore 320 from the second end 304. Extends through position. The distal plug 90 extends the distal end and serves to block intramedullary tissue from entering the bore 308 during insertion and extension. The end plug 90 also has a pair of columnar bores 902, 904 extending therethrough and in communication with the bores 322, 320, respectively.

The key ring 95 (FIG. 9) is a cylindrical member that is dimensioned to pressure fit on the second end 204 of the first cylindrical member 20. The key ring 95 has an inner wall 952 from which a pair of opposing protrusions 954, 956, each having a width 958, extends into the bore 960. In assembly, protrusions 954 and 956 are coupled to opposing slots 234 and 236 in first cylindrical member 20 and opposing slots 314 and 316 in second cylindrical member 30. The purpose of the key ring 95 is to prevent excessive rotation of the first cylindrical member 20 and the second cylindrical member 30 while allowing sufficient relative rotation to actuate the clutch. Thus, the width 958 of the protrusions 954 and 956 should be less than the slot widths 238 and 315 to allow sufficient relative rotation to actuate the clutch mechanism and also be within the normal anatomical limb rotation range. In a suitable embodiment rotation of 3 ° is allowed.

The extension rod 40 shown in FIGS. 4A and 4B has a first end 402, a second end 404, a length 408, and a diameter 406. The threaded portion 410 of the rod 40 extending from the second end 404 is dimensioned to engage the threaded region 336 of the second cylindrical member 30. Non-threaded formation 412 extends from first end 402. Partial diameter bore 414 and full diameter bore 416 extend into non-threaded formation 412. Upon assembly (see FIGS. 1A and 1B), the first end 402 is located within the full range of the bore 208 of the first cylindrical member 20, and the threaded region 336 of the second cylindrical member 30. Screwed into), thereby being rotatably coupled and extending in the longitudinal direction as will be apparent below.

The display mechanism 50 (see FIGS. 1A and 1B) is attached to the non-threaded formation 412 of the extension rod 40 at the first end 402 as shown in detail in FIGS. 5A and 5B. The indication mechanism 50 includes an indicator housing 52, a piston 54 and a spring 53.

The indicator housing 52 is a hollow octagonal element having an outer circumference 520 dimensioned to hermetic fit within the third zone 228 of the bore 208 of the first cylindrical member 20. The indicator housing 52 also has a bore 522 having four identical cutouts 526 radially equidistantly spaced (90 ° from each other) about the bore 522, the cutout 526. ) Has a radial range 528. Bore 522 also has a minimum diameter 524 over an area of bore 522 spaced apart from cut 526. The minimum diameter 524 is hermetically coupled to and enclosed with the non-threaded formation 412 of the extension rod 40.

The piston 54 and the cut portion 526 are shaped to be hermetically coupled to each other. The radial contour 542 of the piston 54 has a straight edge 56 and an inclined edge 544 that are colinear with the radius of the extension rod 40. The radial range 548 of the piston 54 is greater than the radial range 528 of the cut 526. The cutout 526 has a radial contour 541 with an inclined edge 543 and a straight edge 545 facing away from the bend 544. The inclined and straight edges of the piston and the cutout are aligned when the piston is positioned in the cutout.

Upon assembly (see FIGS. 1A and 1B), the spring 53 is inserted into the bore 414 in the rod 40 and the piston 54 is inserted into the bore 414 on top of the spring 53. The indicator housing 52 then fits over the first end 402 of the rod 40, so that the piston 54 is located in one cut 526 and partially extends into the bore 414. The relative rotation between the indicator housing 52 and the rod 40 is opposed toward the straight edge 546 in the first direction 548, but may also be opposed towards the inclined edge 544 in the second direction 549. You can see that. However, when rotation in the second direction 549 occurs, sufficient torque is applied to overcome the friction coefficient of the mechanism and the spring constant of the spring 53, so that the spring 53 compressed by the piston 54 Is pressed into the bore 414. As shown in FIG. 5B, when sufficient rotation occurs in the second direction such that the piston 54 is fully positioned into the bore 414, little torque is required to continue the rotation. When a 90 ° rotation is achieved, the piston 54 reaches the next cut 526 and audible sound is emitted as the piston 54 snaps into the cut 526 when the spring 53 is released.

In a dependent embodiment, the audible sound may be a signal that sufficient torque has been applied to overcome the resistance of the indicator mechanism and thus a warning to the patient that progressive elongation may occur.

In another dependent embodiment, a magnetic field can be applied to move the piston into the bore 714 and release the indicator mechanism.

In another dependent embodiment, as shown in FIG. 5C, the indicator mechanism 50 ′ includes a pair of opposing pistons 54, 54 ′ and a full diameter bore extending fully through the extension rod. In this configuration, the spring 53 'is held in the bore by a pair of pistons. The housing and the extension rod are rotated relative to each other in the second direction from the pair of opposing cuts to the pair of adjacent opposing cuts as described above.

It will be appreciated that other dependent embodiments may also include different numbers of cuts radially spaced at equal intervals. For example, three cuts may be spaced 120 degrees apart. The flexibility provided by these various indicator mechanisms allows for custom design of stretch parameters without changing any other factors.

An indicator bearing 55 is also attached to the non-threaded formation 412 of the extension rod 40, the cylindrical member being dimensioned to be hermetically coupled to the non-threaded formation 412 (see FIGS. 1A and 1B). It has a longitudinal bore 552. Diameter bore 554 communicates with bore 416, with locking pin 58 inserted through bore 554, 416 and retaining bearing 55 on the rod 40. In assembly, the bearing 55 is located in the third zone 228 of the bore 208 in the first cylindrical member 20 adjacent the indicator mechanism 50 and further towards the second end 204.

The first clutch 60, shown in FIG. 6, is dimensioned such that it is sufficiently hermetically engaged within the second zone 224 of the bore 208 of the first cylindrical member 20 such that rotational movement is transmitted therebetween. It has an outer peripheral portion 620. In another embodiment, as shown in FIG. 10, the first clutch 60 is screwed into a threaded formation in the second zone 224 of the bore 208, and is retained by a retaining bushing 64. Stay in place. The first clutch 60 is also hermetically coupled to the non-threaded formation 412 of the extension rod 40 and has an inner diameter 604 dimensioned to transmit rotational movement therebetween. In assembly, the first clutch 60 is mounted on the non-threaded portion 412 between the indicator bearing 55 and the threaded portion 410. The first clutch 60 allows sliding between the rod 40 and the first cylindrical member 20 when rotation occurs in the first direction and transmits rotation therebetween.

The second clutch 70 having the same structure as the first clutch 60 shown in FIG. 6 is dimensioned so as to be sufficiently hermetically engaged within the maximum width region 340 of the second cylindrical member 30 such that rotational motion is transmitted therebetween. It has a predetermined outer peripheral portion 702. The second clutch 70 also has an inner diameter 740 that is coupled to the thread forming portion 410 of the rod 40 and dimensioned to move longitudinally along it. The directionality of the second clutch 70 allows locking between the rod 40 and the second cylindrical member 30 when rotation occurs in the first direction and the rotation in the second direction generates a rotational slip, Thus allowing linear movement between the rod 40 and the member 30. When the stretching device 10 is fully assembled, rotation in the second direction moves the second clutch 70 along the thread forming portion 410 of the rod 40 toward the second end 404, The thread forming portion 410 is moved longitudinally from the thread forming region 336 of the bore 308 in the second cylindrical member 30. This relative longitudinal movement acts to press the second cylindrical member 30 from the first cylindrical member 20 and the stretching device 10.

Specifically, the clutches 60, 70 include a cylindrical clutch housing 702, a clutch cage 704, an end cap 706, four clutch springs 708, and twelve clutch rollers 710.

The clutch housing 702 has a bore 711 having an inner surface 712, a first end 701 and a second end 703. The inner surface 712 has sixteen asymmetrical radial cuts 713 with a gentle slope 714 in the first direction and a steep slope 716 in the second direction.

The clutch cage 704 defines a first ring-shaped end 718 and a second ring-shaped end 720 spaced apart by four equally spaced support members 722 attached to opposing surfaces 719,721 of the ends 718, 720. It includes each. Each of the opposing surfaces 719 and 721 has columnar channels 726 and 727 therein, respectively. The second end 720 is dimensioned to slide into the first end 701 of the clutch housing 702, the first end 718 being larger than the clutch housing 702 and thus of the clutch housing 702. It does not slip through the first end 701.

Each clutch roller 710 includes a cylindrical member having a first narrow end 734 and a second narrow end 736. One set of three clutch rollers 710 is located between adjacent support members 722, the first end 734 is located in channel 727 and the second end 736 is located in channel 726. . In assembly, the clutch roller 710 with the cage 704 in the housing 702 is deflected against the steep inclined portion 716 by a spring 708 mounted on the support member 722. The roller 710 may not rotate in the second direction via the steep slope 716 of the housing, but may rotate in the first direction via the gentle slope 714. This selective rotationality provides clutch directionality.

In order to complete the assembly, an end cap 706 having a fitting lip 738 dimensioned to fit within the housing bore 711 is placed above the housing 702 at the second end 703. do.

Since the clutches 60 and 70 are all over-rotating roller clutches, very small rotations cause stretching. Indeed, a small twist of 1 ° within the normal range of physiological movement can lead to stretching of the stretching device 10. Thus, no external manipulation is required, and small progressive longitudinal development can occur over one day rather than many large kidneys per day, which is required for conventional devices, and a more suitable state for promoting bone growth. The only external operation required is to release the display mechanism 50. Indeed, for humans, the device is designed to allow an elongation of 0.20 to 0.25 mm per 90 ° rotation of the elongation rod 40 and the manipulation to release the instrument is 4 per day for a total elongation of 1 mm per day To six times is required.

In another embodiment of the clutch structure shown in FIG. 14, the clutch 61 includes a cylindrical clutch housing 612, a clutch cage 614, an end cap (not shown), eight clutch springs 618, and eight clutches. Has a roller 610. The principle of operation is the same as described for clutches 60 and 70 except that there is one clutch spring 618 for each clutch roller 610.

Another embodiment of a roller clutch is shown in FIG. 13 showing an integral roller / spring / cage assembly 62 dimensioned to be inserted into the housing 702. In the assembly 62, which may be formed by, for example, laser cutting or metal injection molding, the cylindrical “cage” portion 622 of the structure is mutually and with the cage portion 622 for the spring portion 626. The interconnect forms a window having an opening 624 in which the spring portion 626 and the roller portion 628 are supported.

In this clutch 62 design, the first end 625 of each leaf spring 626 is coupled to a roller 628 near its center. The second end 627 of each leaf spring 626 is coupled to the longitudinal portion 621 of the cage 622 near its center. Each roller portion 628 is supported only by the first end 625 of the leaf spring, thereby allowing some relative movement therewith. Under tension, the clutch is operated in a manner similar to the clutch described above in that the roller portion 628 is constrained to rotate in the second direction by the shape of the housing 702 and is allowed to rotate in the first direction. In this case, however, the roller 628 does not rotate completely, but rather rotates slightly and applies a force to the leaf spring 626. Spring portion 626 includes a loop of metal that is flexible enough to allow clutch rotation under physiological conditions but sufficient rigidity to constrain free movement.

In the embodiment shown in FIG. 13, there are thirteen roller / spring units. It should be noted that the numbers are exemplary and not restrictive, but the structure of the clutch should be balanced. The smaller the number of rollers, the larger the diameter, which limits the diameter of the extension rod and the wall thickness of the cylindrical member. The larger the number of rollers, the smaller the diameter, which allows the wall thickness of the elongate rod or cylindrical member to be larger and thus stronger. However, if the number of rollers is too large, the clutch is inoperable and becomes very weak, so the operable range in this embodiment is 8 to 16 rollers, which is not limiting and actually operates clutches having a larger number of rollers by new materials. It may be possible.

The method of using the apparatus described above includes the following steps (see FIG. 7). An incision is made at the head of the cut bone 60 to be treated, through which the stretching device 10 is inserted into the spinal cord of the bone. The first cylindrical member 20 and the second cylindrical member 30 are attached to the proximal cutout 602 and the distal cutout 610 of the bone 60 by screws 604, 607, 608, respectively. When a torsional movement occurs in the first direction, the second clutch is moved along the threaded portion of the elongate rod and presses the second cylindrical member away from the first cylindrical member to elongate the device. Rotation continues to stretch the device until it reaches a 0.25 mm extension, at which point the indication mechanism is locked for additional extension. At the end of the quarter day, the secondary agent or the patient himself is forced to rotate the limb until the piston is pushed into the bore in the extension rod and clutch movement again occurs. When the limb is promoted to allow bone cutting point 601 to grow to a desired length, the stretching device is removed from bone 60 or left in place as an internal splint.

<2nd Example>

In the stretching device 12 of the second embodiment shown in FIG. 10, in order to determine from the external part the amount of stretch movement that occurs between the first cylindrical member 20 and the second cylindrical member 30 from the predetermined starting position. Means for communicating with the extension rod 42 are provided. The movement amount determining means includes signal generating means, and the generated signal indicates the rotational position of the extension rod 42.

In a particular embodiment, the signal generating means comprises a magnet 43, such as a rare earth element magnet having a pole (N-S) axis 432 radially oriented relative to the extension rod 42. Since the magnet 43 is constrained in the rotational direction with respect to the extension rod 42, the movement of the extension rod 42 is transmitted to the magnet 43 whereby the magnetic field indicates the rotational position of the extension rod 42.

As shown in FIG. 10, the extension rod 42 has a partial longitudinal bore 422 from the second end 424 and is dimensioned to place a magnet 43 therein. The hermetic coupling is secured by a plug 44 which tightly surrounds the second end 434 of the magnet and which fits within the bore 422 sufficiently tightly so that rotational movement is transmitted between the magnet 43 and the elongation rod 42. Is provided.

Within the vertical range of physiological movement, the magnet 43 is fully rotated twice per day and measured every four hours by, for example, an electronic Hall effect sensor 49 that detects the direction and magnitude of the magnetic field (FIG. This can be taken. A microprocessor 48 in communication with the sensor 49 counts the change in magnetic field from the north pole to the south pole, which is related to one half of the thread pitch, which provides a measure of the elongation generated. Optionally, the sensor can continue to be worn on the patient and examined whenever desired.

<Third example>

In this embodiment of the intramedullary skeletal stretching device 14 (FIGS. 11A-11D), the first cylindrical member 20, the second cylindrical member 32 and the stretching rod 42 are the same as described above. However, since the rod 42 is coupled to the second cylindrical member 32, the relative rotational movement of the rod 42 is converted into a relative axial movement between the rod 42 and the second cylindrical member 32.

In particular, the rod 42 has a threaded portion 426 positioned to engage the supplemental threaded portion 362 of the bore 334 of the second cylindrical member. The rotation of the rod 43 thus causes a longitudinal movement between the rod 42 and the second cylindrical member 32.

The stretching device 14 of the present embodiment also includes rotation executing means attached to the stretching rod 42 in response to the extracorporeal rotation generating signal. In a particular embodiment, the rotational execution means comprises a magnetic signal responsive material, such as magnet 45, so that the circumferentially oriented magnetic signal causes the rotation of the responsive material and the corresponding rotation of the extension rod 42.

In order to retain the elongate rod 42 in the bore of the first cylindrical member 20, the bushing 64 is screwed into a point adjacent to the first end 202 of the first cylindrical member. The bushing 64 is dimensioned to fit over the first end 421 of the extension rod but is not in contact with the movement. A retaining screw 63 is then inserted into the threaded bore 423 in the first end 421 of the rod which serves to retain the bushing 64 in an encircling relationship with the rod 42.

The method using this embodiment of the present invention thus comprises transmitting a magnetic signal from the second magnet 47 to the magnet 45. The magnetic signal should have a columnar element sufficient to drive the magnet 45 and the rod 42 in rotation. In operation, the second magnet 47 is placed outside the limb, including the stretching device 14, and rotated in the direction to achieve stretching (half of the magnet 47 as shown in FIG. 11A). Clockwise movement).

In the foregoing description, certain terms have been used in a simplified, concise, and understandable manner, but do not make unnecessary limitations that have meanings in excess of the requirements of the prior art, as these terms are used herein for description and are in their broadest interpretation. Because it can be. Moreover, embodiments of the devices illustrated and described herein are by way of example and the scope of the invention is not limited to the precise details of the structure.

The construction, operation and use of suitable embodiments of the present invention and the novel advantages and useful results obtained thereby have been described, the new useful structures and understandable mechanical identity being apparent to those skilled in the art and the invention is described in the claims.

Claims (12)

An intramedullary skeletal extension device for use in a bone marrow cavity of a cut bone, First and second cylindrical members each having a first end, a second end, and a bore; An extension rod having a first end and a second end, the extension rod having a diameter dimensioned to slide into the second cylindrical member; Rotational responsive clutch means positioned in an enclosed relationship with respect to the elongate rod within the bore of the first cylindrical member, Signal generating means for communicating with the stretching rod to determine an amount of stretching movement generated between the first and second cylindrical members from a predetermined starting position from an external part, and generating a signal indicating a rotational position of the stretching rod It includes a means including; The second cylindrical member is dimensioned to be slidably stretchable into the first cylindrical member, The first end of the rod is located in the bore of the first cylindrical member and attached to the first cylindrical member, the second end of the rod is located in the bore of the second cylindrical member, The clutch means is positioned to prevent an axial load from being applied, is rotatable in a first direction and locked in a second direction, and extends and contracts the first and second cylindrical members when rotating in the first direction. Is also operable on the second cylindrical member to effect movement; The signal generating means includes a magnet having a polar axis oriented radially with respect to the elongating rod, the magnet being rotationally constrained with respect to the elongating rod, and the magnetic field of the magnet indicating the rotational position of the elongating rod. My skeletal kidney device. 2. The intramedullary skeletal stretching device of claim 1, wherein the clutch means is operated to effect stretching by rotation in a first direction of at least 1 °. 3. The clutch of claim 2, wherein the clutch means comprises a first clutch located between the first ends of the first and second cylindrical members, and a second clutch located in the bore of the second cylindrical member, The first clutch has an outer diameter dimensioned to hermetically fit within a bore of the first cylindrical member such that movement is transmitted therebetween, and rotation of the first cylindrical member in the second direction is such that Has an inner diameter dimensioned to effect rotation and to fit in tight relationship with the extension rod such that rotation of the first cylindrical member in the first direction allows sliding of the extension rod, The second clutch has an outer diameter dimensioned to tightly fit in the bore of the second cylindrical member such that movement is transmitted therebetween, and rotation of the first cylindrical member in the first direction is directed to the elongate rod. And has an inner diameter dimensioned to fit in tight relationship with the elongate rod to effect rotation about the second rod and allow rotation of the first cylindrical member in the second direction to allow sliding of the elongated rod, The second cylindrical member also has a moving means for moving relative to the elongate rod, wherein rotation in the second direction extends the second clutch and the second cylindrical member outward relative to the first cylindrical member. An intramedullary skeletal extension device that moves relative to the rod and thereby performs a stretch movement that is elongated. 4. The intramedullary skeletal extension device of claim 3, wherein the extension rod has a thread at a second end and the means for movement includes means for moving and engaging along the thread. 5. The intramedullary skeletal extension device of claim 4, wherein the first and second clutches comprise first and second over-rotating roller clutches. 6. The intramedullary skeletal stretching device of claim 5, wherein the first and second over-rotating roller clutches respond to rotations of at least 1 [deg.]. The method of claim 1, The elongate rod has a partial longitudinal bore from the second end, And the magnet is coupled to the longitudinal bore of the elongated rod and sized to be positioned therein in an airtight manner so that rotational movement is transmitted therebetween. An intramedullary skeletal extension device for use in a bone marrow cavity of a cut bone, First and second cylindrical members each having a first end, a second end, and a bore; An elongate member having a first end and a second end, the elongate member having a diameter dimensioned to slide into the bore of the second cylindrical member, A rotation execution means attached to the elongate member and responsive to an extracorporeal rotation generation signal, The second cylindrical member is dimensioned to be slidably stretchable into the first cylindrical member bore, The first end of the rod is located in the bore of the first cylindrical member and attached to the first cylindrical member, the second end of the rod is located in the bore of the second cylindrical member, and the second end of the rod Is coupled to the second cylindrical member such that the relative rotational movement of the rod is converted into a relative axial movement between the rod and the second cylindrical member. 9. The intramedullary skeletal stretching device of claim 8, wherein the rotational execution means comprises a magnetic signal responsive material, whereby the circumferentially directional magnetic signal causes the rotation of the responsive material and the corresponding rotation of the elongated rod. . The method of claim 9, The second end of the rod is threaded, The bore of the second cylindrical member has a supplemental thread to the second end thread of the rod, the bore thread of the second cylindrical member is positioned to engage the second end thread of the rod, Rotation of the rod causes intramedullary skeletal stretching device to effect longitudinal movement between the rod and the second cylindrical member. A method of performing progressive stretching of a cut bone having a proximal end, a distal end, and a bone marrow, First and second cylindrical members each having a first end, a second end, and a bore, and an elongate member having a first end and a second end and having a diameter dimensioned to slide into the bore of the second cylindrical member. Wherein the second cylindrical member is dimensioned to be slidably stretchable into the first cylindrical member bore, the first end of the rod being located in the bore of the first cylindrical member and in the first cylindrical member. And a second end of the rod is located in the bore of the second cylindrical member, the second end of the rod is coupled to the second cylindrical member such that relative rotational movement of the rod is achieved by the rod and the second cylindrical member. Providing an intramedullary bone skeletal device that translates into relative axial movement between members; Inserting the stretching device into the bone marrow of the bone, Attaching the first cylindrical member to a near cut of the bone; Attaching the second cylindrical member to the distal cut of the bone; Executing rotation of the elongation rod by an extracorporeal rotation generation signal, thereby generating an elongate movement that is elongated. The method of claim 11, Providing the stretching device also includes providing a magnetizable material attached to the stretching rod, And said rotating execution step includes transmitting a magnetic signal to said magnetizable material, said signal having a columnar element for rotationally driving said material and said elongation rod.