DE202007017159U1 - Tension screw system for the treatment of fractures particularly suitable for stability-reduced bones - Google Patents

Abstract

Tension screw system consisting of different, combinable components, which allows the stable supply of fractures even with porous bones.
The screws can be combined as single lag screws or in combination with existing neutralization plates commonly used in modern orthopedic surgery, dynamic compression plates, angle stable plate systems, intramedullary nails, washers and Kirschner wires to achieve compression and, if necessary, angular fixation of bone fractures.
This is also achieved with reduced stability bones, as the screws are supported by the osteosynthesis plates and / or washers resting on the bone surface and traction is developed by screwing the screw shafts into the screw sleeves.
The screw components are to be adapted to the respective conditions in terms of diameter, length and with regard to the washers used.
The screw shafts and screw sleeves are hollow-> drilled (cannulated) and can thus be introduced via guidewires even via small surgical access (minimally invasive) and brought together (Seldiger technique).
The sleeve parts without screw head can be coupled with a target arc ...

Description

State of the art:

The Compression of fractured surfaces has a favorable effect on bone healing. This is currently achieved through the use of different systems, such as lag screws, which are threaded in the Bone anchoring of dynamic compression plates, intramedullary nails or tension straps.

Problem:

The oa. However, systems rely on a stable bone structure enough for the screws Stop giving to the desired one To achieve compression. When using tension straps the problem is that the rippling wire is angled regularly with respect to the inserted Kirschner wires runs. Thus, according to the laws of vector geometry, only a part the tension is initiated in the direction of Kirschner wires and is called Compression force at the fracture gap effective. In addition, a caterpillar wire not in all cases applied directly to the surface of the bone surface Become. Intermediate soft tissues, e.g. Craving give within a short time Time after and originally he witnesses tension is lost again.

Solution:

The featured screws can with the help of washers, Kirschner wires or Osteosynthesis plates transfer pressure to the bone surfaces by screwing the thread of the shaft component is produced with the sleeve. That's one corresponding voltage can be generated even with stability-reduced bones.

The Direction of compression force can be determined by the off direction of the screw axis perpendicular to the fracture surface lossless be exercised on the fracture surface.

The cannulation The screw components allowed in favorable cases, the placement in the so-called "Seldinger technique" on small Stichinzisionen without to expose the break.

design:

• 1. Hülse mit Linsenkopf und Innengewinde (M 3 bzw. M 4)
• 2. Hülsenteil mit Innengewinde (M 3 bzw. M 4) und Außengewinde am Schraubenkopf
• 3. Hülsenteil wie 1. zusätzlich mit einem Außen-Gewinde auf dem Hülsenschaft (M 4 bzw. M 5)
• 4. Schaftteil mit einem Außengewinde (M 3 bzw. M 4) und Linsenkopf
• 5. Hülsenteil ohne Schraubenkopf mit Innengewinde (M 3 bzw. M 4) und 2 queren Bohrungen von je 2,0 mm Durchmesser mit 2,0 und 6,0 mm Abstand vom Hülsenende
• 3. spindelförmige, 15,0 mal 7,0 mm große, um die Querachse um 4,0 mm gebogene Unterlegscheiben mit einer zentralen Bohrung von 4,0 mm

The screw components are designed as follows:

• 1. sleeve with Linsenkopf and internal thread (M 3 or M 4)
• 2. Sleeve part with internal thread (M 3 or M 4) and external thread on the screw head
• 3. sleeve part as 1. additionally with an external thread on the sleeve shank (M 4 or M 5)
• 4. Shank part with an external thread (M 3 or M 4) and Linsenkopf
• 5. Sleeve part without screw head with internal thread (M 3 or M 4) and 2 transverse bores of 2.0 mm diameter each with 2.0 and 6.0 mm distance from the end of the sleeve
• 3. Spindle-shaped, 15.0 by 7.0 mm, washers around the transverse axis of 4.0 mm, with a central bore of 4.0 mm

The screw parts are available in 2 sizes in terms of diameter: screw head 6.0 and 7.0 mm,
Sleeve: 4.0 and 5.0 mm
Screw shank: 3.0 and 4.0 mm

The screw heads are equipped with a hexagonal hex socket for size 2.5 screwdrivers.

The screw sleeves and screw shafts are in the lengths of 20, 30, 40, 50 and 60 mm available, giving a span from a minimum of 20 mm to a maximum of 110 mm is possible.

Handling:

at The presence of a suitable fracture (for example the kneecap, the joint near the joint) Thigh, shinbone or upper arm, of the elbow, inner or ankle or other bones) becomes closed or open preferably perpendicular to the fracture surface a Kirschner wire in strength introduced the screw shank. Then the wire with a cannulated Drill in strength the screw sleeve overdrilled until the fracture gap. It follows the replacement of the Kirschner wire against a guidewire of Strength 0.8 mm. about This wire, the two screw components are guided to each other and screwed together. According to the requirements round or special spindle-shaped Washers used to transfer the pressure flat on the bone.

At the minimally invasive procedure, the implants along Stichinzisionen along of the target wire introduced.

at the combination of the screw is done with a stable angle plate the setting of the borehole by means of a screwed drill sleeve, the Angle to the plate pretends to be an angular stable screw of the casehead to enable.

If the screw is used to a locking locking the corresponding Markna gels with simultaneous compression of fracture surfaces, a male threaded sleeve is used, which screwed into the locking locking hole of the nail. The compression is again achieved by means of counter-screwed shaft screw with washer (eg fractures on the distal thigh with splitting of the joint parts).

at the supply of demolition fractures e.g. At the elbow is in the corresponding drill hole a sleeve without Screw head on a targeting bar coupled into the main fragment and inserted with 1 or 2 cross over the aiming arm out 2 mm Kirschner wires anchored.

The wires be outside of the bone bent over, shortened and the bone surface created to avoid dislocation. The stable reduction the demolished fragment under appropriate compression of the Breaking gap is about the shaft screw with washer.

Needed instruments:

• - Kirschner wires 2.0 mm and 0.8 mm
• - cannulated Drill bit 4,0 and 5,0 mm
• - 2 cannulated Hexagonal screwdriver 2.5 mm

pictures:

1 : Sleeve ( 1 ) with female thread and Linsenkopf ( 2 )
Shaft screw ( 3 )
0.8 mm Kirschner wire ( 4 )

2 : Sleeve ( 1 ) with inner and head thread ( 5 )
Shaft screw ( 3 )
0.8 mm Kirschner wire ( 4 )

3 : Sleeve ( 1 ) with female thread, Linsenkopf ( 2 ) and external thread ( 6 )
set screw 3 )
0.8 mm Kirschner wire ( 4 )

4 : Sleeve with internal thread without head ( 7 ) with 2 transverse holes with a diameter of 2 mm ( 8th )
Shaft screw ( 3 )
0.8 mm Kirschner wire ( 4 )
Spindle-shaped washer ( 9 )
Aiming arm to sleeve ( 7 ) ( 10 )
Cannulated fixation screw of the aiming device ( 11 )
2.0 mm Kirschner wires for locking ( 12 )

5 : Spindle-shaped washer ( 9 )

Advantages:

The presented screw system allows in combination with various washers, osteosynthesis plates and intramedullary nails the stable supply of fractures under compression of the fracture gap and if necessary angle stable even with stability-reduced Bones in the orthopedic Surgery, in auspicious Fall over too minimally invasive approaches.

Supply Examples:

• 1. Patella transverse fracture with 2 parallel lag screws each with 2 spindle-shaped washers
• 2. Olecranon fracture with cross-locked sleeve without head and 1 spindle-shaped washer
• 3. Condylar distal humeral fracture with lag screw and 2 round washers
• 4. internal malleolar fracture with cross-locked sleeve without Head and spindle-shaped washer
• 5. Tuberculum majus - fracture with cross-locked sleeve without head and spindle-shaped washer
• 6. Distal femur fracture: Combination sleeve with external thread and retrograde Nail with angular stable recording in the locking hole and 2 round washers and at the same time: Proximal tibial fracture: Combination sleeve with head thread with angle-stable plate (LISS) and 1 round washer.

Claims (1)

Tension screw system consisting of different, combinable components, which allows the stable supply of fractures even with porous bones. The screws can be combined as single lag screws or in combination with existing neutralization plates commonly used in modern orthopedic surgery, dynamic compression plates, angle stable plate systems, intramedullary nails, washers and Kirschner wires to achieve compression and, if necessary, angular fixation of bone fractures. This is also achieved with reduced stability bones, as the screws are supported by the osteosynthesis plates and / or washers resting on the bone surface and traction is developed by screwing the screw shafts into the screw sleeves. The screw components are to be adapted to the respective conditions in terms of diameter, length and with regard to the washers used. The screw shafts and screw sleeves are hollow-> drilled (cannulated) and can thus be used to guide Wiring wires are also introduced via small surgical access (minimally invasive) and led together (Seldiger technique). The sleeve parts without screw head can be coupled with a target arc introduced into corresponding bone holes and cross-locked with one or two Kirschner wires of dimension 2.0 mm. This allows as an abutment for the shaft screw with washer safe compression of fractured surfaces, for example, in tears on the elbow, ankle or similar fractures.