Abstract: A bone screw of minimally invasive fixation device for lumbar comprises a positioning casing and a screw body. The positioning casing includes a rod securing base and an alignment portion, both of which are integrally formed; an annular notch is formed between them. The alignment portion has at least two pairs of rod alignment openings in a bulb-shaped or keyhole-shaped form with an upper portion larger than a lower portion. Two longitudinal notches extend from near the top across the alignment openings to the rod securing base. The screw body includes a spherical head and a screw rod; the outer diameter of the spherical head is larger than that of the screw rod. The screw body is rotatably connected to the bottom portion of the positioning casing; the spherical head of the screw body is arranged in the spherical pit of the rod securing base.

Abstract: The percutaneous minimally invasive pedicle fixation system herein comprises a bone screw and a hook-rod, wherein the bone screw includes a positioning casing and a screw body. The positioning casing comprises securing base, an alignment casing and a screw body passage. The securing base includes a through hole at the bottom and two openings arranged opposite to each other in the wall. The alignment casing has a wall portion and a volume reduce portion, wherein the wall portion is configured with an elongate opening and the volume reduced portion is a portion with part of the wall removed to recede from the outer surface of the securing base and a guide opening formed in the volume reduced portion. The positioning casing further includes a first easy breaking portion between the alignment casing and the securing base so that the alignment casing can be removed from the positioning casing.

Abstract: A spinal spacer includes a first plate, a second plate and a middle plate. The first and second plates are in one stack and spaced from each other with a distance. The middle plate is located between the first plate and the second plate, wherein the middle plate connects with the first plate and forms a first gap, and connects with the second plate and forms a second gap. The first plate and the second plate can move relative to the middle plate which leads to deformation of gaps.