WO2019185104A1

WO2019185104A1 - The gear dynamic compression plates

Info

Publication number: WO2019185104A1
Application number: PCT/EG2019/000007
Authority: WO
Inventors: Ahmed Mohamed Abou Elainen ELKHAWAGA
Original assignee: Elkhawaga Ahmed Mohamed Abou Elainen
Priority date: 2018-03-28
Filing date: 2019-03-26
Publication date: 2019-10-03

Abstract

The current invention seeks to provide surgeons with a new method depending on mechanism of rank and pinion to get unlimited compression of fractures especially in minimally invasive techniques and also it helps in correction of angular deformities by distraction after osteotomy.

Description

The Gear dynamic compression plates

Technical Field

The present invention relates to gear plating system used in orthopedic surgeries to compress or distract the bone edges in patients with fractured bones, or angular bone deformities.

Background Art

There are numbers of surgical procedures which involve the fixation of bone fracture by plates or correction of small angular bone deformities using plates.

In bone fractures the surgeons have to mount the plate on the tension side of the bone to act by a tension band mechanism. Then reduction of the fracture edges is done and screws are tightened to compress the fracture edges. The better in fracture reduction is to gain cortical contact between fracture edges to get good bone union.

At the beginning there were dynamic compression plates that have dynamic holes and depend on application of the screws at eccentric positions to get the compression.

Appearance of osteolysis beneath the dynamic compression plates because of contact with the bone surface led to appearance of the low contact plates that have beveling of the undersurface of the plate to decrease contact with bone surface and locked plates that have threaded holes and threaded heads of the screws to act as internal external fixators.

In many situations the reduction and the compression of fracture edges are lost and there are critical sites of bone fracture that limit the capability of the surgeon to expose the bone because of fearing to endanger other vital tissues or due to inaccessibility.

Indirect compression tools are used in these situations, but their uses need more bone exposure with its complications. Also there are indirect reduction techniques and uses of minimally invasive plating techniques but it lacks the good compression.

In cases of angular deformities planned for correction by osteotomy and plating the surgeon faces the difficulties in adjusting the proper angle of correction and also the lost reduction after osteotomy.

There are many plates used in correction of angular deformity and each type of plates has its function to be suitable with type of bone deformity.

The current invention is different from SURGICAL COMPRESSION PLATE AND DRILL GUIDE by Klaue US 4,493,317 as the latter invention is used to compress fracture fragments together by the plate and screws through it but this need a good exposure of the all bone fragments and makes more devitaliziation of soft tissue coverings of the bone. Also its power of compression is limited when used with large bones as the tibia and the femur.

The current invention is different from BONE PLATE SYSTEMS USING PROVISIONAL FXATION by Gerlach et al. US 7,909,858 B2 as it is of limited amount of compression especially when used in minimally invasive techniques.

The current invention is different from COMPRESSION PLATEKIT AND METHODS FOR REPAIRING BONE DISCONTINUITIES by Schelling US 9,011,507 B2 as there are many tools for compression and the compression screws should be removed after compression and replaced by fixation screws,

The current invention is different from BONE PLATE SYSTEM FOR OPENING WEDGE PROXMAL TIBIAL OSTEOTOMY by Puddu US 5,620,448 as the fixed projection of the plate is of multiple sizes, each size for a precise angle of correction but the current invention can correct many angles by one plate.

Ilizarov external fixator used from decades in correction of angular deformities but the lost reduction after osteotomy and psychological effects on the patients are main problems.

Problem of prior Art:

The limited amount of resulted compression when using the ordinary dynamic compression plates. The locked dynamic compression plates cannot be handled easily when dealing with compression. Chances of lost reduction and compression are not uncommon. Some uses a tool for compression that necessitates more bone exposure and devitalize more tissues. In certain critical sites the compression is not easy to do hence more exposure may endanger other vital tissues and in fracture pelvis the compression is very difficult by plates because of the tight access to fractured bones. The main problem when using plates with minimally invasive techniques is inability to get enough compression of the fracture edges. The lost reduction after osteotomy and the psychological hazards of using external fixators especially illizarov in deformity correction.

- Side Effects:

a- Iatrogenic bone fracture if the surgeon over compress the fracture edges,

b- Friction between the gear head teeth and the smooth bar may results in abrasion of the plate alloy and separation of minute parts of plate materials,

c- Non union, mal union and delayed union. d- Complications resulted from surgery in general such as hemorrhage, contamination and screw and plate breakage.

References

Citations:

CN105828732A, CN201426768Y, EP0865258B1 , US4493317, US5620448,

US5971984, US6102911, US7744638, US7909858, US8029507, US8172885, US9011507, US9060822, US9579134, US9877755, US10149707, US20140025123 Al, US20120109143A1 and US20150216565A1

Publications:

Campbell's Operative Orthopaedics 13th-(elsevier) 2017

BRIEF DESCRIPTION OF THE DRAWINGS

1. Fig. 1 (A): shows a perspective view of a cut section in a Gear dynamic compression plate in accordance with the present invention.

2. Fig. 1 (B): shows a perspective view of the under surface of a Gear dynamic compression plate in accordance with the present invention.

3. Fig. 1 (C): shows a perspective view of an upper view of gear screws in position in a Gear dynamic compression plate in accordance with the present invention.

4. Fig. 1 (D): shows a schematic view of a gear reconstruction plate with the same mechanism of Gear dynamic compression plate in accordance with the present invention.

5. Fig. 2 (A-F) shows a perspective view different types of screws used in Gear dynamic compression plate in accordance with the present invention.

6. Fig. 2 (G) shows a perspective view from above to a gear screw in accordance with the present invention.

7. Fig. 2 (H) shows a perspective view from below to a gear screw in accordance with the present invention. Disclosure of the invention:

The present invention aims to provide surgeons with a new way to treat bone fractures and deformities. This invention consists of a gear plate that is mounted to the bone. The plate has two gear holes, or all holes in gear reconstruction plates. There are other ordinary locked holes surround each gear hole for fixation to bone.

- Bone exposure and reduction of fracture edges is done.

- The plate is mounted over tension side of bone and preliminary fixed by bone holders.

- The bone is punctured through one of the peripheral locked holes, then width is measured and locked screw is advanced and not tightened.

- At the other gear hole of the plate the bone is punctured at the eccentric side of the gear hole and a gear screw is advanced up to compression of the fracture edges is done the all other screws are advanced and if the first gear screw head not reached the whole depth of the plate then we can change it by an ordinary screw.

- When the plate used for distraction in deformity correction the first gear screw is put in concentric side of the gear hole until reaching the eccentric side of the hole and when more distraction is needed the other gear hole is used by the same technique and rest of screws are advanced and tightened.

- The gear reconstruction plate is used by the same technique.

Detailed Description:

(Including operation method in case of devices, tools & equipment, or chemical preparation method in case of chemical & agricultural substances, and laboratory experiments and side effects)

The Gear dynamic compression plates are composed of set of geared plates having a geared hole or more arranged along the length of the plate or at the proximal or distal ends of the plate. Also the system composed of set of geared screws of different shapes and functions and ordinary fixing screws. Its mechanism of action depends on rank and pinion to transport motion from screw on the plate to the bone.

1) The Gear dynamic compression plates (Fig.l) :

a- The Gear dynamic compression plates (Fig.l -A) is a rectangular plate having holes arranged in longitudinal direction of the plate as follows:

• Near an edge of the plate (1 -Al) at its upper surface (1-A2) there is a sloped rounded opening or hole (1-A3) ended by a threaded part of the hole (1-A4) that ends at the lower surface of the plate. This hole is designed to be filled by a locked screw (2- A). • The gear hole is separated from the locked hole by a short distance and started by a smooth arch (1-A5) called eccentric arch that ends at one side by a rack (1-A6) that is composed of fixed cogged or toothed bar. The other end of the arch is continuous with a smooth bar (1-A12) at the opposite side of the toothed bar, and both bars ended by another arch (1-A7) called concentric arch to complete the oval shape of the gear hole. The both arches. Toothed bar and smooth bars are occupying only part of the depth of the gear hole but the other part is occupied by an oval border (1-A11) to prevent sinking of head of the gear screw (2-B-F) and as a smooth base for easy rotation. This border could be absent in low profile type of plates.

• The first tooth bar should be at the left side of the plate when it stands upright and should be placed on the distal fragment of the fracture site planned for compression.

• After short distance of the gear hole there is another locked hole (1-A8) resembles that near edge of the plate.

• After each set of adjacent holes there is a longer distance (1-A9) in each plate.

That longer distance bisects the plates having even number of holes and lies near the center in plates having an odd number of holes.

• After that longer distance the other half of the plate is repeated like a mirror image. The difference will be in the position of bars of the gear hole, the gear hole starts by a concentric arch (1-A10) (near the center of the plate) and ended at one side by a toothed bar that lies (1-C4) at an opposite side to that on the first half of the plate (1-C3). Also the other end of the concentric arch is continuous with the smooth bar that lies on a side of the plate (1-C3) opposite to the same bar (1-C4) on the first half of the plate. Both bars ended by an eccentric arch (1-A13) (near periphery of the plate).

• Some modifications could be added to the plate as sharp edge of the lower surface for easy elevation of the periosteum especially in minimally invasive techniques. b- Geared reconstruction plates (1-D):

These are type of plates characterized by presence of constrictions (1-D1) at both sides after each oval hole. The gear hole likes that of that hole of gear compression-distraction plate but it lacks the oval border and there are alternations of the position of the toothed and smooth bars at each gear hole (1-D2& D3). The first tooth bar should be at the left side of the plate when it stands upright and should be placed on the distal fragment of the fracture site planned for compression.

c- The gear hole could replace the dynamic holes in any linear plates to enhance the minimally invasive techniques in fractures planned for compression. These types of plates should have two gear holes. The toothed bar of the lower gear hole should be placed on the right side of the plate and the toothed bar of the upper gear hole should be placed on the left side of the plate when we look at an upper surface of the plate.

2) The geared screws (Fig. 2):

These are set of locked and gear screws for multiple functions like compression, distraction, reduction and fixation through the holes of geared plates:

a- The locked screw (2-A): like any screw it is composed of a head and tail. The head is circular have a hexagonal depression to fit with a screw driver (as shown in 2- G2). The upper surface of the head is circular and of larger diameter than the threaded part. It slopes from below (2-A1) to end with the threaded part (2-A2) of the locked head that is locked with the threaded part of the locked hole (1-A4). The tail of the locked screw is fully threaded to be suitable for advancement with clockwise rotation and.

b- The polished gear screw (2-B): is composed of a gear head (2-B1) and a tail (2- B2). The head is circular have a hexagonal depression to fit with a screw driver (as shown in 2-G2). The upper surface of the head is circular (2-G1) and of larger diameter than the gear part (2-G3). The gears of the gear screw (2-G3) are of conical teeth arranged (2-H2) in circular manner with its base to the center of screw and its apex directed outwards. The teeth of the gear screw (2-H2) separated by conical spaces (2-H3). The under surface of the circular part of the gear screw (2-H1) cover the upper part of the teeth of the gear head (2-H2). The lower part of the said teeth is angled (2-H4) to decrease friction with the smooth bar of the plate (1-A12). The said angled parts of the teeth ended by the smooth undersurface of the head (2-H5). The tail is polished (2-B2) and ended by a tapering conical end (2-B3). During movement of the gear screw the teeth of the gear head are interdigitating with that of the toothed bar (1-C5) while the teeth of the second half of the gear strikes the sooth opposing bar (1-C6). The function of said screw is to transfer movement from plate to bone indirectly when large distance of movement is required. When compression is desired the polished screw is put eccentric and clockwise rotation in needed. When distraction is desired the screw is put concentric and anticlockwise rotation is needed. When function is ended the screw is removed and replaced by an ordinary screw. The amount of compression or distraction is estimated. When small amount of compression or distraction is desired it is wise to put the gear screw along the desired position (1-C7) and moves it eccentric (1-C9) or concentric (1-C8).

c- The geared fully threaded clockwise screw (2-C): it is formed of head and tail (2- Cl). The said head resembles that of the polished gear screw (2-B1) but the tail (2- Cl) is fully threaded in a clockwise manner. The function of said screw is to compression and fixation also of a compressed bone to the surface of the plate. So the said screw is rotated in clockwise direction and moves (1-C7) from eccentric (1-C9) to concentric (1-C8) positions. So there is no use to replace said screw as polished screw hence said screw will fix the compressed bones in position, d- The geared fully threaded anticlockwise screw (2-D): it is formed of head and tail (2-D1). The said head resembles that of the polished gear screw (2-B1) but the tail (2-D1) is fully threaded in an anticlockwise manner. The function of said screw is distraction and fixation also of distracted bones to the surface of the plate. So the said screw is rotated in anticlockwise direction and moves (1-C7) from concentric (1-C8) to eccentric (1-C9) positions. So there is no use to replace said screw as polished screw hence said screw will fix the distracted bones in position.

e- The geared partially threaded clockwise screw (2-E): it is formed of head and tail (2-E1& E2). The said head resembles that of the polished gear screw (2-B1) but the tail (2-E1& E2) is partially polished (2-El) partially threaded (2-E2) in a clockwise manner. The function of said screw is compression, withdraw a bone fragment to fix it and fixation also of compressed bones to the surface of the plate. It acts also to decrease the working length of said screw to rest the head on the plate rapidly in desired small distance of compression. So the said screw is rotated in a clockwise direction and moves (1-C7) from eccentric (1-C9) to concentric (1-C8) positions. So there is no use to replace said screw as polished screw hence said screw will fix the compressed bones in position

f- The geared partially threaded anticlockwise screw (2-F): it is formed of head and tail (2-F1& F2). The said head resembles that of the polished gear screw (2-B1) but the tail (2-F1& F2) is partially polished (2-F 1 ) partially threaded (2-F2) in an anticlockwise manner. The function of said screw is distraction; withdraw a bone fragment to fix it and fixation also of distracted bones to the surface of the plate. It acts also to decrease the working length of said screw to rest the head on the plate rapidly in desired small distance of distraction. So the said screw is rotated in a clockwise direction and moves (1-C7) from concentric (1-C8) to eccentric (1-C9) positions. So there is no use to replace said screw as polished screw hence said screw will fix the distracted bones in position,

g- Some modifications could be added to enhance function of the threaded screws as beveling of both sides of the lower tapering end of the threaded screws to be self taping.

Claims

1) The Gear dynamic compression plates comprising:

(a) The Gear dynamic compression plates (Fig.l-A) is a rectangular plate having holes arranged in longitudinal direction of the plate. The said plates have gear holes and locked holes.

(b)The geared reconstruction plates (Fig. l-D) are linear or curved plates characterized by presence of constrictions (1-D1) at both sides after each oval hole. All its holes have gears in an alternating manner.

(c) The gear hole may be added to any type of plates.

(d)The locked screws (2-A) that function to stabilize reduction of bones.

(e) The gear screws (2-B-F) that composed of set of screws characterized by having a gear in its head

2) The Gear dynamic compression plates according to claim 1, wherein said the Gear dynamic compression plate (Fig. l-A) is a rectangular plate having holes arranged in longitudinal direction of the plate

3) The Gear dynamic compression plate according to claim 2, wherein said near an edge of the plate (1-A1) at its upper surface (1-A2) there is a sloped rounded opening or locked hole (1-A3) ended by a threaded part of the hole (1-A4) that ends at the lower surface of the plate.

4) The Gear dynamic compression plate according to claim 2, wherein said there is presence of a gear oval hole at the surface of the said plate that is started by a smooth arch (1-A5) called eccentric arch that ends at one side by a rack (1-A6) that is composed of fixed cogged or toothed bar. The other end of the arch is continuous with a smooth bar (1-A12) at the opposite side of the toothed bar, and both bars ended by another arch (1-A7) called concentric arch to complete the oval shape of the gear hole. Both arches toothed bar and smooth bars are occupying only part of the depth of the gear hole but the other part is occupied by an oval border (1-A11) to prevent sinking of head of the gear screw (2-B-F) and as a smooth base for easy rotation. This border could be absent in low profile type of plates.

5) The Gear dynamic compression plate according to claim 4, wherein said first tooth bar should be at the left side of the plate (1-C3) when it stands upright (1-Cl is up) hence this will be the proximal gear hole. In distal gear hole (1-C2 is down) the tooth bar should be located at the right side of the plate (1-C4). Arrangement of the tooth bars at these positions did not interfere with the ordinary clockwise rotation of the gear screw in most cases of compression.

6) The Gear dynamic compression plate according to claim 2, wherein said after short distance of the said gear hole there is another locked hole (1-A8) resembles that near edge of the plate.

7) The Gear dynamic compression plate according to claim 2, wherein said after each set of adjacent holes there is a longer distance (1-A9) in each plate. That longer distance bisects the plates having even number of holes and lies near the center in plates having an odd number of holes.

8) The Gear dynamic compression plate according to claim 2, wherein said after said longer distance the other half of the plate is repeated like a mirror image. The difference will be in the position of bars of the gear hole, the gear hole starts by a concentric arch (1-A10) (near the center of the plate) and ended at one side by a toothed bar that lies (1-C4) at an opposite side to that on the first half of the plate (1- C3). Also the other end of the concentric arch is continuous with the smooth bar that lies on a side of the plate (1-C3) opposite to the same bar (1-C4) on the first half of the plate. Both bars ended by an eccentric arch (1-A13) (near periphery of the plate).

9) The Gear dynamic compression plate according to claim 2, wherein said modifications could be added to the said plate as sharp edge of the lower surface for easy elevation of the periosteum especially in minimally invasive techniques.

10) Geared reconstruction plates (1-D) according to claim 1, wherein said these are linear or curved plates characterized by presence of constrictions (1-D1) at both sides after each oval hole for remodeling. The gear hole likes that of that hole of gear compression-distraction plate but it lacks the oval border and there are alternations of the position of the toothed and smooth bars at each gear hole (1-D2& D3). The first tooth bar should be at the left side of the plate when it stands upright and should be placed on the distal fragment of the fracture site planned for compression.

11) The geared hole according to claim 2& 10, wherein said could replace any dynamic hole in any linear plate enhance the minimally invasive techniques in fractures planned for compression.

12) The locked screw (2-A) according to claim 1, wherein said composed of a head and tail. The head is circular have a hexagonal depression to fit with a screw driver (as shown in 2-G2). The upper surface of the head is circular and of larger diameter than the threaded part. It slopes from below (2-A1) to end with the threaded part (2- A2) of the locked head that is locked with the threaded part of the locked hole (1- A4). The tail of the locked screw is fully threaded to be suitable for advancement with clockwise rotation and.

13) The geared polished screw according to claim 1, wherein said the polished gear screw (2-B) is composed of a gear head (2-B1) and a tail (2-B2). The said head is circular have a hexagonal depression to fit with a screw driver (as shown in 2-G2). The upper surface of the head is circular (2-G1) and of larger diameter than the gear part (2-G3). The gears of the gear screw (2-G3) are of conical teeth arranged (2-H2) in circular manner with its base to the center of screw and its apex directed outwards. The teeth of the gear screw (2-H2) separated by conical spaces (2-H3). The under surface of the circular part of the gear screw (2-H1) cover the upper part of the teeth of the gear head (2-H2). The lower part of the said teeth is angled (2- H4) to decrease friction with the smooth bar of the plate (1-A12). The said angled parts of the teeth ended by the smooth undersurface of the head (2-H5). The tail is polished (2-B2) and ended by a tapering conical end (2-B3).

14) The geared fully threaded clockwise screw (2-C) according to claims 1& 13, wherein said it is formed of head and tail (2-C1). The said head resembles that of the polished gear screw (2-B1) but the tail (2-C1) is fully threaded in a clockwise manner. The function of said screw is to compression and fixation also of a compressed bone to the surface of the plate.

15) The geared fully threaded anticlockwise screw (2-D) according to claims 1, 13& 14, wherein said is formed of head and tail (2-D1). The said head resembles that of the polished gear screw (2-B1) but the tail (2-D1) is fully threaded in an anticlockwise manner. The function of said screw is distraction and fixation also of distracted bones to the surface of the plate.

16) The geared partially threaded clockwise screw (2-E) according to claims 1, 13& 14, wherein said it is formed of head and tail (2-E1& E2). The said head resembles that of the polished gear screw (2-B1) but the tail (2-E1& E2) is partially polished (2-El) partially threaded (2-E2) in a clockwise manner. The function of said screw is compression, withdraw a bone fragment to fix it and fixation also of compressed bones to the surface of the plate. It acts also to decrease the working length of said screw to rest the head on the plate rapidly in desired small distance of compression. 17) The geared partially threaded anticlockwise screw (2-F) according to claims 1, 13& 15, wherein said it is formed of head and tail (2-F1& F2). The said head resembles that of the polished gear screw (2-B1) but the tail (2-F1& F2) is partially polished (2-F1) partially threaded (2-F2) in an anticlockwise manner. The function of said screw is distraction; withdraw a bone fragment to fix it and fixation also of distracted bones to the surface of the plate. It acts also to decrease the working length of said screw to rest the head on the plate rapidly in desired small distance of distraction.

18) The geared screws according to claims 1, wherein said some modifications could be added to enhance function of the threaded screws as beveling of both sides of the lower tapering end of the threaded screws to be self taping.