US 12,082,852 B2
Locking compression members for use with bone anchor assemblies and methods
Thibault Chandanson, Villers le lac (FR); Ernest Quintanilha, Norton, MA (US); Frank Spratt, Middleboro, MA (US); and Philip A. Cormier, Newburyport, MA (US)
Assigned to Medos International Sàrl, Le Locle (CH)
Filed by Medos International Sarl, Le Locle (CH)
Filed on Mar. 31, 2021, as Appl. No. 17/218,416.
Application 17/218,416 is a continuation of application No. 16/403,114, filed on May 3, 2019, granted, now 10,987,138.
Application 16/403,114 is a continuation of application No. 15/643,075, filed on Jul. 6, 2017, granted, now 10,321,938, issued on Jun. 18, 2019.
Application 15/643,075 is a continuation of application No. 14/987,812, filed on Jan. 5, 2016, granted, now 9,724,130, issued on Aug. 8, 2017.
Application 14/987,812 is a continuation of application No. 13/827,092, filed on Mar. 14, 2013, granted, now 9,259,247, issued on Feb. 16, 2016.
Prior Publication US 2021/0212730 A1, Jul. 15, 2021
Int. Cl. A61B 17/70 (2006.01); A61B 17/00 (2006.01)
CPC A61B 17/7037 (2013.01) [A61B 17/7032 (2013.01); A61B 2017/00477 (2013.01); A61B 2017/00526 (2013.01); A61B 17/7035 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A bone screw assembly, comprising:
a screw having a proximal head portion and a distal shank portion;
a receiver member having a polyaxial seat formed therein and configured to polyaxially seat the head portion of the screw;
a compression cap disposed within the receiver member and having a distal end configured to engage the head portion of the screw, the compression cap including opposed projections extending radially therefrom configured to mate with complementary recesses formed in the receiver member such that the compression cap is retained within the receiver member when the compression cap is rotated relative to the receiver member,
wherein rotation of the compression cap relative to the receiver member about a longitudinal axis of the receiver member urges the compression cap distally against the proximal head portion of the screw to provide a friction force that locks the screw in a fixed position relative to the receiver member and contacts proximal-facing surfaces of the opposed projections with corresponding surfaces of the complementary recesses while the compression cap is urged distally,
wherein the rotation of the compression cap from an unsecured position to a retained position moves the opposed projections from a position where the opposed projections are free to move proximally out of the receiver member to a position in which the opposed projections are captured by the complementary recesses in the proximal and distal directions, and
wherein the angled proximal-facing surfaces of the opposed projections are angled inwardly towards the longitudinal axis of the receiver in the distal direction, and
wherein the opposed projections are formed from a flexible material and are configured to be distally deflected by corresponding surfaces of the complementary recesses as the compression cap rotates from the unsecured position to the retained position.