Closure assembly for securing a stabilization element in a receiving part of a bone anchoring device

A method of coupling an elongate stabilization element to a bone or vertebra using a bone anchoring device comprising a shank for anchoring in the bone or vertebra, a receiving part pivotably connectable to the shank, the receiving part comprising two legs defining a U-shaped recess therebetween for receiving the elongate stabilization element, and a closure assembly for securing the elongate stabilization element in the receiving part, the closure assembly comprising a first closure member receivable between the legs of the receiving part, the first closure member having an axis of rotation and comprising an outer surface with a first threaded portion comprising a single-start thread formed on at least a portion thereof that is configured to engage the legs of the receiving part, and an inner surface having at least a portion that is threaded, the inner surface defining a central passage that passes axially through the first closure member, and a second closure member having an axis of rotation and an outer surface with a second threaded portion comprising a multi-start thread with at least two starts that are configured to cooperate with the threaded portion of the inner surface of the first closure member, the method comprising:

• anchoring the shank to the bone or vertebra;
• adjusting an angular position of the receiving part relative to the shank;
• inserting the elongate stabilization element into the U-shaped recess of the receiving part;
• inserting the closure assembly into the receiving part;
• advancing the first closure member into the receiving part to lock the angular position of the receiving part relative to the shank;
• and
• advancing the second closure member into the receiving part to lock the elongate stabilization element in the U-shaped recess of the receiving part.