Intervertebral expandable cage system and its instrument

Abstract

An expandable cage (1) for maintaining a distance between two vertebras on a spine and providing fusion is disclosed. The expandable cage (1) comprises a horizontal axis, a front part with an upper arm (1.1), a lower arm (1.2), and shaft fixation sockets (1.7.1 and 1.7.2) located between the arms (1.1 and 1.2), and a hollow shaft (2) with graft holes (2.4). The shaft (2) is placed parallel to the horizontal axis and partially inside the shaft fixation sockets (1.7.1 and 1.7.2). The cage (1) is expanded vertically by rotating the shaft (2) 90 degrees with an instrument, thus further separating vertically the upper arm (1.1) and the lower arm (1.2).

Claims

1. An expandable cage (1) system comprising: a vertically expandable front part, a back part, a lower surface, an upper surface, an open position, a closed position, a cage length measured from the back part to the front part, an upper arm (1.1) located at the front part, a lower arm (1.2) located at the front part, an expandable cage cut (1.3) located between the upper arm (1.1) and the lower arm (1.2), an outer socket (1.7.1) located inside the expandable cage cut (1.3), an inner socket (1.7.2) located inside the outer socket (1.7.1), lower and upper teeth (1.4) respectively located at the lower and the upper surfaces, an instrument hollow (1.5) located at the back part, a threaded instrument hole (1.6) located at the back part, a central space (1.8), a horizontal axis extending from the back part to the front part, and a shaft (2) extending from the back part to the front part, the shaft (2) being restricted to a single 90 rotation movement around the horizontal axis and having: a shaft length being substantially the same as the cage length; a frontal expansion end (2.1) placed at the front part in the outer socket (1.7.1); a cornered back end (2.2) placed at the back part; and a shaft body (2.3) located between the frontal expansion end (2.1) and the cornered back end (2.2), wherein a. at the closed position, the frontal expansion end (2.1) of the shaft (2) sits in the outer socket (1.7.1), b. during the 90 rotation movement of the shaft (2), the frontal expansion end (2.1) slides from the outer socket (1.7.1) into the inner socket (1.7.2), and c. after the 90 rotation movement of the shaft (2), the system irreversibly reaches the open position, the upper arm (1.1) and the lower arm (1.2) are further separated, and the frontal expansion end (2.1) is locked in the inner socket (1.7.2) to prevent accidental movement of the shaft (2).

2. An expandable cage (1) system according to claim 1, wherein the shaft (2) has no further rotational moving capability around the horizontal axis after the single 90 rotation movement configured for the system to irreversibly transit from the closed position to the open position.

3. An expandable cage (1) system according to claim 1, wherein a. the back end (2.2) and the shaft body (2.3) are hollow, b. the shaft body (2.3) further comprises at least one hole (2.4), and c. the back end (2.2) further comprises a graft filling hole (2.5) configured for a bone graft to be injected into the shaft (2) after the system is inserted between vertebras.

4. An expandable cage (1) system according to claim 1, wherein the back end (2.2) of the shaft (2) is square or hexagonal or octagonal and the frontal expansion end (2.1) is rectangular prism-shaped.

5. An expandable cage (1) system according to claim 1, wherein a height of the inner socket (1.7.2) is greater than a height of the outer socket (1.7.1), and a width of the frontal expansion end (2.1) of the shaft (2) at the closed position is greater than a height of the frontal expansion end (2.1) and the height of the inner socket (1.7.2).

Description

DESCRIPTION OF FIGURES AND REFERENCE NUMBERS

(1) In order to explain the invention better, drawingswhich is detailed beloware attached: 1. General overview of the expandable cage system 2. Back view of the expandable cage system 3. General overview of the shaft 4. General overview of the instrument 5. General overview of the of the disassembled instrument

(2) Parts of the Figures are numbered as follows: 1. Expandable Cage 1.1 Expandable cage upper arm 1.2 Expandable cage lower arm 1.3 Expandable cage cut 1.4 Lower and upper teeth 1.5 Instrument hollow 1.6 Threaded instrument hole 1.7 Shaft fixation socket 1.7.1 Outer socket 1.7.2 Inner socket 1.8 Central space 2. Shaft 2.1 Frontal expansion end 2.2 Cornered back end 2.3 Shaft body 2.4 Graft holes 2.5 Graft filling hole 3. Instrument 3.1 Handle 3.2 Shaft Adapter 3.2.1 Shaft adapter end 3.2.2 Shaft adapter handle 3.3 Cage Fixator 3.3.1 Outer cage fixator 3.3.1.1 Cage fixator claw 3.3.2 Inner cage fixator 3.3.2.1 Cage fixator threads 3.3.2.2 Inner cage turning fixator 3.3.2.3 Shaft adapter handle stopper.

DETAILED DESCRIPTION OF THE INVENTION

(3) The intervertebral expandable cage system and its instrument which is the scope of this invention, comprise of in general terms; an intervertebral expandable cage (1), a shaft (2) which is placed into the expandable cage (1) in parallel with expandable cage (1) axis and an instrument (3) which enables the system to be implanted between the vertebras.

(4) The expandable cage (1) shown in detail in FIG. 1-2 comprises of; an expandable cage upper arm (1.1) which enables the cage (1) to be expandable, an expandable cage lower arm (1.2), an expandable cage cut (1.3), lower and upper teeth (1.4) which enables firm hold of the cage (1) into the vertebras, an instrument hollow (1.5) and a threaded instrument hole (1.6) and an outer socket (1.7.1) which the frontal expansion end (2.1) of the shaft (2) will fit into in closed position and an inner socket (1.7.2) which the frontal expansion end (2.1) of the shaft (2) will fit into and fixed in open position and a central space (1.8) which is suitable for bone graft filling in case of a need.

(5) The cage (1) is preferable made of PEEK (polyetheretherketone) material. However it can be made of from stainless steel, titanium, titanium alloy, carbon, ceramic or a material that is bio compatible and strong enough to prevent damaging of the structure.

(6) There are lower and upper teeth (1.4) on the lower and upper surfaces of the cage (1) that are in parallel to the cage (1) horizontal axis. These upper and lower teeth (1.4), after the cage (1) is implanted between the vertebras, enable it to be firmly situated and prevent the cage (1) to move backwards especially.

(7) At the back of the expandable cage (1), there is an instrument hollow (1.5), which enables cage fixator threads (3.3.2.1) at the end of the instrument (3) to be fixed to the cage (1) and a threaded instrument hole (1.6) which the shaft adapter end (3.2.1) at the end of the instrument (3) goes into. Instrument hole (1.6) can be in a threaded form or can have a cavity, tab, teeth or thread which will allow the inner cage fixator (3.2.2) to grasp the end of it. As an advantage, instrument hollow (1.5) and threaded instrument hole (1.6) are placed in such a way that they enable using a single instrument (3) which can perform all processes.

(8) As an advantage, there are shaft fixation sockets (1.7) on the expandable cage upper arm (1.1) and expandable cage lower arm (1.2) which are placed at the front of the expandable cage (1). When the shaft (2) is turned to open position, that is when the cage is expanded, the frontal expansion end (2.1) of the shaft (2) sits in the inner socket (1.7.2) and system fixation is achieved. In the pre-cage expansion position, frontal expansion end (2.1) sits in the outer socket (1.7.1) in a fixed position. With the turning movement applied by the instrument (3) to the shaft (2), the frontal expansion end (2.1) of the shaft (2) slides from outer socket (1.7.1) to the inner socket (1.7.2) and provides a secure locking and expansion with the help of the effective fixation. Thanks to the sliding claw structure in the shaft fixation sockets (1.7), a clear information as to the completion of the locking is provided to the surgeon.

(9) The shaft (2) as shown in detail in FIG. 3; comprises of frontal expansion end (2.1), cornered back end (2.2), shaft body (2.3), graft holes (2.4) and graft filling hole (2.5).

(10) The shaft (2) is preferable made of titanium alloy material. However it can be made of from stainless steel, PEEK (polyetheretherketone), titanium, carbon, ceramic or a material that is bio compatible and strong enough to prevent damaging of the structure.

(11) Preferably and as an advantage, the cornered back end (2.2) of the shaft (2) has a hexagonal form which enables a suitable instrument to grip it and turn the shaft (2) in the desired direction and angle. It is also possible that the back end of the shaft (2.2) can be in different cornered geometrical forms or state of the art structures which enable the instrument (3) to grip it. Thus, due to the hexagonal back end of the shaft (2.2), during surgery, the shaft (2) can firmly be turned, until the expandable cage upper arm (1.1) and expandable cage lower arm (1.2) are expanded in proper angle between the vertebras and frontal expansion end (2.1) of the shaft (2) sits on the inner socket (1.7.2) at the front of the expandable cage (1).

(12) As an advantage, the shaft (2) is located in the middle of the cage (1). Due to this, during surgery, it is possible to place bone grafts to speed up the fusion process into the central space (1.8) in the middle of the expandable cage (1). As an advantage, due to round shape of the body (2.3) of the shaft (2) and keeping its initial volume during the movement, the expansion movement does not affect the structure of the bone grafts.

(13) As an advantage, the shaft (2) has a hollow interior and there are graft holes (2.4) on it. After the expandable cage (1) is implanted into its place between the vertebras, during the surgery, with the help of the graft filling hole (2.5) at the back of the shaft (2), a suitable bone graft can be injected into the shaft (2). The bone graft which is injected through graft filling hole (2.5) fills into the central space (1.8) in the middle of the expandable cage (1) with the help of graft holes (2.4) on the shaft (2).

(14) The instrument (3) shown in detail in FIGS. 4 and 5, comprises a handle (3.1) which enables firm grip of the instrument (3), cage fixator (3.3) and shaft adapter (3.2). Furthermore, cage fixator comprises an outer cage fixator (3.3.1) and an inner cage fixator (3.3.2). There are cage fixator claws (3.3.1.1) at the tip of the outer cage fixator (3.3.1). The inner cage fixator (3.3.2) comprises cage fixator threads (3.3.2.1) at its tip and an inner cage turning fixator (3.3.2.2) and a shaft adapter handle stopper (3.3.2.3).

(15) As an advantage, the cage fixator claws (3.3.1.1) which are at the tip of outer cage fixator (3.3.1), are designed to sit into instrument hollow (1.5) at the back of the cage (1). When the cage fixator claws (3.3.1.1) is fixed into instrument hollow (1.5), with the help of lower and upper tabs located at the back of the cage (1) which outlines the lower and upper frame of the hollow (1.5), the rotating movement of outer cage fixator (3.3.1) is prevented and the first step of the fixation is achieved. Secondly, inner cage fixator (3.3.2) achieves the second fixation by turning the inner cage turning fixator (3.3.2.2) (this turning movement enables the cage fixator threads (3.3.2.1) to hold on to the threads in the threaded instrument hole (1.6) at the back of the cage (1)). With this fixation, sitting of the shaft adapter end (3.2.1) on the cornered back end (2.2) of the shaft (2) is also achieved. In this way, the instrument (3) fixes the expandable cage (1) by holding firmly on to the instrument hole (1.6) at the back of the expandable cage (1).

(16) As an advantage, the shaft adapter end (3.2.1) is designed to fit firmly to the cornered back end (2.2) of the shaft (2). In this way, the shaft (2) can be fully and strongly turned and the expandable cage (1) is brought to expanded position.

(17) As an advantage, the shaft adapter handle (3.2.2) at the back of the instrument (3) is designed such that it can be firmly grasped by the hand of the surgeon and can move only 90 degrees. The turning movement of the shaft adapter handle (3.2.2) is limited by the shaft adapter handle stopper (3.3.2.3) on the inner cage fixator (3.3.2). In this way, it is ensured that the shaft (2) cannot be turned more than 90 degrees in the expandable cage (1) and the irreversibility of the expansion property of the system is secured.

(18) In a sample application of the invention;

(19) The height between the vertebras in the operation area is measured and suitable size of the expandable cage (1) is determined. The suitably sized expandable cage (1) is locked to the instrument (3), with the help of threaded instrument hole (1.6) and instrument hollow (1.5) at the back of the expandable cage (1). During locking, the shaft adapter (3.2) is properly fitted to the cornered back end (2.2) of the shaft (2). Then the expandable cage (1) is implanted to its place between the two vertebras with the help of the instrument (3). After the expandable cage (1) is implanted, with the help of shaft adapter handle (3.2.2) of the instrument (3), the frontal expansion end (2.1) of the shaft (2) is turned 90 degrees, simultaneously sliding from outer socket (1.7.1) to the inner socket (1.7.2) at the front part of the expandable cage (1); then the expansion is achieved. In this way, the expansion is achieved by moving the expandable cage upper arm (1.1) and expandable cage lower arm (1.2) of the expandable cage (1) in opposite directions and the lower and upper teeth (1.4) fit completely into the vertebras. After controlling the position and the angle of the expandable cage (1) preferably with various imaging methods and being ensured of the proper position, the instrument (3) can be released from the cage (1) by turning the inner cage turning fixator (3.3.2.2) in the opposite direction. After that if requested, the bone graft can be injected into the shaft (2) with the help of graft filling hole (2.5) at the back of the shaft (2) and by using a proper apparatus. The filled in graft will flow through the graft holes (2.4) on the shaft (2) and fills the central space (1.8) within the cage (1), thus speeding up the fusion is ensured.

(20) The invention is described by way of example above. Of course, the invention cannot be limited with the above described applications and the person skilled in the art can implement various variants of the invention without going beyond the ambit of the patent.