| 摘要 |
A Top-Loading Bi-Polar bone anchor apparatus is disclosed. The apparatus includes a receiver member, internal threaded ring member, a bi-polar member, a bone anchor and a compression retaining member. The receiver member defines an upper opening and a lower opening, which may form part of the same opening, a channel, and external threaded portion located at the bottom. The Bi-Polar member and bone anchor are loaded into the lower opening of the receiver member thru the bottom of the receiver member, and internal threaded ring member fits around the bone anchor and over the outer lower threaded portion in the receiver member to retain the Bi-Polar member and the bone anchor member. The bone anchor is capable of multi-axial positioning as well as multi-polar positioning with respect to the receiver member. An elongated member is placed in the channel of the receiver member, contacting between the bone anchor member, and a compression retaining member is applied via the upper opening. The compression retaining member presses down on the elongated member, which presses down on the bone anchor member and locks the bone anchor member between the retaining member, Bi-polar member, and the receiver member. |
