Patent ID: 8888820

Claim:
A bone attachment device, comprising: (a) a bone fastener having a distal portion adapted to pierce bone and a proximal portion having a head; (b) a collar comprising: (i) a collar wall defining a cavity and having at least one wall aperture; (ii) a distal portion comprising an opening and a collar seat projecting inward and supporting the head of the bone fastener; (iii) a proximal portion having a hinged lid attached to the collar wall with a pivot pin, the hinged lid possessing a central aperture and a lid hook opposite the pivot in wherein the lid hook is adapted to engage a corresponding feature in the collar wall; and (iv) a spinal rod locking device passing through the central aperture in the hinged lid, comprising: (A) a nut, the nut having an outer diameter, the nut being adapted to turn about an axis from an unlocked configuration to a locked configuration, and which possesses a distal cam surface and a collar engagement member projecting radially from only a segment of an outer diameter surface of the nut such that the collar engagement member does not extend around the entire outer diameter of the nut, wherein the distal cam surface is adapted to impart distal force to a clamp member and the collar engagement member is adapted to rotatably engage a collar overhang of the collar wall in the locked configuration and not engage the collar wall in the unlocked configuration; and (B) the clamp member possessing a proximal cam surface, which interacts with the distal cam surface of the nut, and which is adapted to receive distal force from the nut and impart distal force to a rod extending through the at least one wall aperture; wherein at least a portion of the spinal rod locking device is within the cavity defined by the collar wall.