WO2010024787A1

WO2010024787A1 - Long body polyaxial posterior cervical screw

Info

Publication number: WO2010024787A1
Application number: PCT/TR2009/000083
Authority: WO
Inventors: Ugur Tabuktekin
Original assignee: Hays Saglik Urunleri Ic Ve Dis Ticaret Limited Sirketi
Priority date: 2008-08-26
Filing date: 2009-07-08
Publication date: 2010-03-04

Abstract

The invention relates to a poly-axial cervical system (1) used for treatment purposes in case of failure of spinal column to maintain the inter vertebra (2) relations in cervical zone and consisting of screw (3) forming infrastructure in providing stabilization, body (4) having movement capability, rod (5) making the poly-axial cervical system (1) a whole and set screw (6) providing fixation of the rod (5). The said extension part (4.4) prevents remaining of the rod (5) on or by the rod housing (4.2) during stabilization process and serves as bridge during location of the rod (5) into the rod housing (4.2) on the body (4) and thus the rods (5) are pulled into the rod housing (4.2) in a short time period and in a neat manner.

Description

DESCRIPTION LONG BODY POLYAXIAL POSTERIOR CERVICAL SCREW

THE RELATED ART

The invention relates to posterior cervical long body poly-axial screw providing practicality for the surgeon during operation and developed for use to eliminate the disorders occurring in cervical zone.

The invention particularly relates to a posterior cervical long body poly axial screw developed in order to eliminate the problems encountered during application of screws used in the surgical treatment method applied for treatment of loss of capability to sustain inter vertebral relations occurring under spinal column physiological loads occurring as a result of trauma, degeneration or metastatic lesion in cervical zone and also to make the operation practical.

BACKGROUND OF THE RELATED ART

Spine called column vertebralis consists of combination of bone structures hosting cerebra spine called vertebra and containing spinal cord or medula spinalis. The said spine is surrounded by bond tissue called ligament. The parts of ligmans holding front zone are called onterior ligament while those holding back zone are called posterior ligament. The said vertebras are interconnected by cushions providing flexibility called discus allowing movement of spine by means of prevention of wearing occurring as a result of contact of bones. The said vertebras are collected in 5 main groups. They are the zones of cervical zone containing vertebras from end of cranium to nape of the neck causing paralysis in the arms and lower part of the body in case of damage, thoaracal zone from nape of the neck to the end point where ribs combine with the spine, lumbar zone in the waist zone, sacral zone located in sacrum zone and coxgeal zones on the end parts of sacrum. The vertebras located in the said cervical zone play an essential role in maintaining regular life of a person as they host brain stem and cervical spine in the inner part. Any traumas that might occur in the said cervical zone vertebras may also result in death in addition to serious disabilities. Although there is no chance to 83

2 intervene the spine incision, stabilizing spine in wounding not containing neurologic problem is highly important.

Since characteristics of each vertebra located in the said zones of the spine are different, different surgical interventions and instruments should be applied to each zone. For instance, dorsal thorax and lumbar fixation techniques provide effective spinal stabilization if the load carrying capacity of anterior column has not damaged. Since pedicle diameters are too small in thorax spine, fixation by hook is preferred at this level. On the other hand, pedicle fixation in lumbar zone provides a stronger stability. In general, since approach to the spine is from posterior and the only structure binding the back column and medium and front columns is pedicle, hook-rod systems provide posterior column stability. For that reason, pedicle screw fixation systems are frequently preferred particularly in lumbar spine. Here since the screw passes through pedicle and enters the vertebra, 2 and even 3 columns stabilization can be provided at one time. When compared to rods requiring compression or distraction for stabilization, the screws provide stabilization immediately. However, the purpose of all spinal implant sets is to stabilize the spine during fusion and the rods located on the lamina bond the vertebras to each other by means of pedicular screws or sacral screws through posterolateral way, and are temporary constructions helping regular healing.

Particularly, various posterior systems have been developed from structure of vertebras in cervical zone. The posterior cervical systems used today consist of poly-axial (PX) screws, rods, transverse connections, hooks, oxiput plate and connections. However, the basic member providing stabilization in cervical zone is the poly-axial screws installed onto vertebras planned for operations with their special senders. All of the existing poly-axial screws of the Posterior Cervical Systems are low profiled enabling locking of the rod and therefore the system with the set screw upon insertion cylindrical rod in the canal on the body of the screw. After the said poly-axial screws are connected to vertebra, the rods serving as bridge between the screws connected to the vertebra one after each other are bended as per natural slope of vertebra by use of rod bending hand tools. After this bending process is applied to the rods located on both sides of vertebra, the posterior system becomes ready for combination for stabilization. What should be paid attention during the said combination process is the stage of insertion of rod into poly-axial screw into screw body. Rod and screw may not be at the same level due to the fact that the surgeon gives the slope to the rod not according slope of the patient's vertebra but the required slope during insertion of rod into screw body. Generally rod remains over body canals of one or more screws. Therefore, it will be required to pull the rod into the screw body. The surgeon is required to use different hand tools in order to pull the rods into screw body and position them inside the channel. The most frequently used ones of the said hand tools are persuader, rod pusher and rocker. No matter what the characteristic of the used hand tool is, use of such hand tools causes disadvantages on part of the surgeon. After connecting the screws onto vertebras, the surgeon spends extra power and time to pull the rod into the body. Conduct of this process extends the total time of operation and also causes the patient remain under anesthesia for longer time.

As a result, the need for posterior cervical long body poly-axial screw eliminating the disadvantages of the posterior systems used in cervical zone in the related art and inadequacy of existing solutions have necessitated development in the related art.

OBJECT OF THE INVENTION

From the known status of the related art, the purpose of the invention is to solve the problems mentioned above.

The purpose of the invention is to provide posterior cervical system with elongated body to eliminate the disadvantages encountered as the remaining of the rod on or on right or left of one ore more screws during fixation of the structure provided during stabilization due to anatomical differences.

Another object of the invention is to eliminate the need for use of extra hand tools such as persuader, rot pusher and rockers during pulling the rod to screw body.

A further object of the invention is to reduce the cost and shorten the total operation time as extra hand tools are not used during pulling the rod. Another object of the invention is to allow reduction of vertebra dislocating when the level differences of vertebras called dislocation occurs without need for use of extra thanks to special structure of the posterior cervical system.

A further object of the invention is to provide short time for being under anesthesia for the patient as a result of easy location of rod due to raised body of the posterior cervical screw.

Another object of the invention is to provide a neat sequencing of the screws by means of taking the rods remaining on right or left by means of lying the screw caps on side thanks to poly-axial characteristic of the developed posterior cervical system.

The structural and characteristics features of the invention and all advantages will be understood better in detailed descriptions with the figures given below and with reference to the figures, and therefore, the assessment should be made taking into account the said figures and detailed explanations.

BRIEF DESCRIPTION OF FIGURES

Figure 1 shows general schematic view of demounted poly-axial posterior cervical system.

Figure 2 shows general schematic view of poly-axial posterior cervical system mounted on vertebra.

Figure 3 shows general schematic view of mounted case of the rod when the poly-axial posterior cervical system is on the vertebra.

Figure 4 shows general schematic view of mounted case of insertion of the rod into the body by means of set screw.

Figure 5 shows general schematic view of broken case of the poly-axial posterior cervical system.

REFERENCE NUMBERS

1. Poly-axial cervical system

2. Vertebra 3. Screw 4. Body

4.1. Broken canal

4.2. Rod housing

4.3. Set screw housing 4.4. Extension part

5. Rod

6. Set screw

7. Core

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to poly-axial cervical system (1) provided with easy application by means of raised body (4) used for treatment purposes in case of loss of capability to maintain the inter-relations of spinal column vertebras (2) occurring in cervical zone.

Poly-axial cervical system (1) shown in figure 1 consists of screw (3) inserted into vertebra (2), body (4) connected to the said screw (3) and provided with movement capability, rod (5) making a whole the poly-axial cervical systems (1) connected in a sequenced manner on the vertebra (2) and set screw (6) providing fixation of the rod (5) within the body (4). The function of the said screw (3) is to provide its holding on the vertebra (2) where it is connected and to provide infrastructure for realization of stabilization. The body (4) into which the said screw (3) is connected by means of insertion through provides combination and locking of the rod (5) and the screw (3). In addition, the said body (4) forms the upper part of the stabilization. The said body (4) is characterized in that it consists of an extension part (4.4) in upper part. A breaking canal (4.1) is formed on the body (4) in order to ensure leaving of the said extension part (4.4) upon completion of its duty by means of breaking). Rod housing (4.2) where the rod (5) passes through and is connected and set screw housing (4.3) where the set screw (6) passes through in order to provide fixation after connection of the rod (5) are formed on the said body (4). A core (7) is located in the said body (4) in order to ensure locking of the rod (5) and the screw (3) during compression of the set screw (6). The poly-axial cervical system (1) shown in figure 2 is inserted into the pedicles of the cervical zone in posterior zone by means of specifically designed screw driver after conduct of connection between the body (4) and the screw (3). During the said insertion process, the lower part of the screw (3) goes into the vertebra until level of the body (4). The said body (4) is kept above at a certain distance in order to ensure that it is not influenced by the bone tissue that might develop from the vertebra (2) and to ensure performance of its function. In addition, the said distance also enables the body (4) move poly-axially easier. The said screw (3) insertion process is repeated along the vertebras (2) to be treated.

Upon providing connection between the screw (3) and the body (4) by the vertebra (2) as shown in figure 3, rod (5) is located in order to provide connection between the bodies (4) on the vertebras (2) succeeding each other. Following giving the required form to the said rod (5), it is located in the rod housing (4.2). The said rod (5) becomes an integral part of the poly-axial cervical system (1). Because of the fact that the said vertebras (2) are not in the same plane, remaining the rods (5) located in a neat manner on right or left may occur. Because of the characteristic of the said screw (3) and the body (4), the rod (5) is connected to the rod housing (4.2) easily by tilting. In case of the sliding to right or left, although the movement problem of the said body (4) is solved, the problem of remaining rod (5) above some bodies (4) arising from height difference cannot be solved by this method. The extension part (4.4) formed on the said body (4) makes easy the process of pulling the rod (5) into rod housing (4.2) because of height difference. The said extension part (4.4) provides pulling the rod (5) into the rod housing (4.2) easily without need for use of any extra hand tools. Addition of the said extension part (4.4) to the poly-axial cervical system (1) shortens the operation duration.

The extension part (4.4) shown in figure 4 pushes the rod (5) into the core (7) and locks it without need for any additional tools, equipment or effort, with only set screw (6) after pulling it to the rod housing (4.2). The said set screw (4.3) extends in the set screw housing (4.3) in the body (4) and thus provides pulling the rod (5) into the body (4) towards the core (7). The said set screw (6) also brings the poly-axial cervical system(1) into non-motion position. After the rod (5) shown in figure 5 moves until the end point in the rod housing (4.2) and the said set screw (6) locks the poly-axial cervical system (1), the extension part (4.4) located on the body (4) is moved away by means of breaking through breaking canal (4.1). As the said breaking process is made easily by the surgeon, the poly-axial cervical system (1) is provided with practicality. The said extension part (4.4) prevents remaining of the rod (5) on or by the rod housing (4.2) during stabilization process and serves as bridge during location of the rod (5) into the rod housing (4.2) on the body (4). Thus the rods (5) are pulled into the rod housing (4.2) in a short time period and in a neat manner. The said extension part (4.4) can be manufactured as a single part of the body (4) as well as manufactured as a part separate from the body (4) and then connected onto the body (4).

The protection area of this application has been specified under claims and cannot be limited to the descriptions only given as sampling above. It is obvious that a person skilled in the related art can apply the innovation disclosed by this invention into similar purposed other areas by means of changing the parts in form and using similar structures. Therefore, it is also clear that such embodiments lack of innovation criteria.

Claims

1. The invention is poly-axial cervical system (1) used in the surgical treatment method applied for treatment of the case of loss of capability to maintain inter- vertebral relations occurring as a result of trauma, degeneration or metastatic lesion in cervical zone and under spinal column physiological loads, and consisting of screw (3) forming the infrastructure for providing stabilization by means of connection to the vertebra (2), body (4) connected to the said screw (3) and having moving capability, rod (5) connected in a sequenced manner on the vertebras (2) making the poly-axial cervical systems (1) a whole and set screw (6) providing fixation of the rod (5) in the body (4) and it is characterized in that it consists of extension part (4.4) located on the upper part of the body (4) in order to ensure pulling of the rod (5) to the bodies (4) at different positions from each other due to height differences between the said vertebras (2) without use of extra equipment.

2. Poly-axial cervical system (1) according to claim 1 and it is characterized in that it consists of a breaking canal (4.1) located on the body (4) in order to ensure leaving the said extension part (4.4) upon completion of its duty.