Adjustable double-slot internal spinal fixation apparatus and bone screw

An adjustable double-slot internal spinal fixation apparatus, comprising

• a first base (1), a second base (2), and a connecting rod (3), wherein
• the first base (1) and the second base (2) each contains a U-shaped slot (4) from top to bottom,
• an inner wall of each U-shaped slot (4) contains inner threads,
• the connecting rod (3) is disposed along a horizontal direction,
• the second base (2) contains a long slot (21) along the horizontal direction,
• the connecting rod (3) is capable of swinging in the long slot (21),
• the first base (1) and the second base (2) are capable of relatively rotating on the connecting rod (3),
• one end of the connecting rod (3) is fixedly connected to the first base (1), and the other end of the connecting rod (3) is inserted in the long slot (21) of the second base (2) in a rotatable manner,
• the U-shaped slot (4) on the second base (2) is connected with the long slot (21), a pressing block (5) is disposed in the U-shaped slot (4) of the second base (2), wherein the pressing block (5) has an inverted U-shaped structure adapted to a shape of the connecting rod (3), wherein
• the inverted U-shaped structure has two ends and includes an inner plate (52) and an outer plate (53) at each of the two ends, and a gap (54) is formed between the inner plate (52) and the outer plate (53), wherein a side of the inner plate (52) facing the connecting rod (3) has a shape adapted to an outer wall of the connecting rod (3),
• an annular groove (31) is formed around the connecting rod (3), the connecting rod (3) is inserted to the bottom of the U-shaped slot (4) through the long slot (21), and a limit bump (51) having an annular structure protrudes from the side of the inner plate (52) facing the connecting rod (3) and fits with the annular groove (31) to limit a position of the second base (2) on the connecting rod (3),
• the inner plate (52) is made of an elastic material, and is configured to be elastically deformed when the connecting rod (3) swings in the long slot (21), the connecting rod (3) is capable of rotating with respect to the pressing block (5), and
• the pressing block (5) is capable of rotating inside the U-shaped slot (4) in a horizontal plane while being static relative to the connecting rod (3) when the connecting rod (3) swings in the long slot (21).