An expandable cage configuration that preserves the distance between two vertebrae as preferred during cervical surgical procedures, can be implanted easily, does not cause any infection, and can be used in patients with different body and bone type due to the height-adjustable structure thereof, comprising - at least one body which is located in the emptied area between the damaged vertebrae during the surgical procedure and serves as a disc, which comprises at least one upper surface (2.1) fitted in the upper vertebra and having sparks (2.1.1) on the surface thereof, at least one lower surface (2.2) fitted in the lower vertebra and having spark (2.2.1) on the surface thereof, lateral surfaces (2.3) provided at both sides of the body, at least one front surface (2.4) facing towards the inside of the body according to the vertebrae to which it is positioned, and at least one rear surface (2.5) facing towards the outside of the body according to the vertebrae to which it is positioned and, - characterized by: one lug (2.11) which has a "cam" form being raised in upward direction from the lower portion of the side inner wall (2.7) and is arranged on the side inner wall (2.7); which also presents the portion in which the movable element is fitted at the preferred height; and which preserves the movable element to stabilize at the preferred height, - at least one insert (2.12) which is the portion in which the retainers (3.1) provided at the sides of the movable element are fitted in the position where the movable element, which is placed in the emptied portion inside the body, is not preferred to be raised; which is positioned in the lower portion of the lugs (2.11) disposed on the side inner walls (2.7); and which is arranged perpendicular to the lugs (2.11) and parallel to the lower inner wall (2.9). - at least one movable element which is located on the body and is fitted in the opening made in the body by means of the retainers (3.1) disposed at the sides thereof; which has a toothed surface (3.2) contacting with the upper vertebra and being attached to it; and the height of which can be adjusted by pushing the protrusion (3.3) provided in the lower portion thereof according to the intervertebral distance of the patient by means of the expansion apparatus, - at least one retainer (3.1) which is fitted in the lugs (3.11) when the movable element is not raised within the body; and which is fitted and fixed in the emptied area between the front inner wall (2.6) and front surface (2.4) when the movable element is elevated to the preferred height by means of the expansion apparatus. - at least one protrusion (3.3) which is the component with which the expansion apparatus contacts during the elevation of the movable element, which is positioned in the body, in upward direction by means of the expansion apparatus which at the same time enables the user to rotate the expansion apparatus clockwise and counterclockwise in a way to elevate the movable element. - at least one body which is located in the emptied area between the damaged vertebrae during the surgical procedure and serves as a disc, which comprises at least one upper surface (2.1) fitted in the upper vertebra and having sparks (2.1.1) on the surface thereof, at least one lower surface (2.2) fitted in the lower vertebra and having spark (2.2.1) on the surface thereof, lateral surfaces (2.3) provided at both sides of the body, at least one front surface (2.4) facing towards the inside of the body according to the vertebrae to which it is positioned, and at least one rear surface (2.5) facing towards the outside of the body according to the vertebrae to which it is positioned and, - characterized by: one lug (2.11) which has a "cam" form being raised in upward direction from the lower portion of the side inner wall (2.7) and is arranged on the side inner wall (2.7); which also presents the portion in which the movable element is fitted at the preferred height; and which preserves the movable element to stabilize at the preferred height, - at least one insert (2.12) which is the portion in which the retainers (3.1) provided at the sides of the movable element are fitted in the position where the movable element, which is placed in the emptied portion inside the body, is not preferred to be raised; which is positioned in the lower portion of the lugs (2.11) disposed on the side inner walls (2.7); and which is arranged perpendicular to the lugs (2.11) and parallel to the lower inner wall (2.9). - at least one movable element which is located on the body and is fitted in the opening made in the body by means of the retainers (3.1) disposed at the sides thereof; which has a toothed surface (3.2) contacting with the upper vertebra and being attached to it; and the height of which can be adjusted by pushing the protrusion (3.3) provided in the lower portion thereof according to the intervertebral distance of the patient by means of the expansion apparatus, - at least one retainer (3.1) which is fitted in the lugs (3.11) when the movable element is not raised within the body; and which is fitted and fixed in the emptied area between the front inner wall (2.6) and front surface (2.4) when the movable element is elevated to the preferred height by means of the expansion apparatus. - at least one protrusion (3.3) which is the component with which the expansion apparatus contacts during the elevation of the movable element, which is positioned in the body, in upward direction by means of the expansion apparatus which at the same time enables the user to rotate the expansion apparatus clockwise and counterclockwise in a way to elevate the movable element.