Modular bone fastener assemblies with biased angle receivers

An implantable receiver comprising:

• a body configured to be coupled to a bone fastener and a rod for spinal stabilization, the body comprising a longitudinal axis, wherein the body further comprises:
• a base defining an opening from a top end to a bottom end of the base, wherein a bottom axis of the bottom end of the base is obliquely angled with respect to the longitudinal axis;
• and
• a chamber defined within the base and in communication with the opening, wherein the chamber comprises an upper section, a lower section, and a tapered shoulder between the upper section and the lower section, wherein a chamber axis is obliquely angled with respect to the longitudinal axis;
• a retainer comprising a upper portion and a lower portion, wherein the retainer is disposed in the chamber between the upper section and lower section, wherein the retainer is configured to expand in the upper section of the chamber to receive a bulbous head of the bone fastener up through a bottom opening of the retainer, and wherein the upper portion of the retainer is wider than the lower portion of the retainer;
• and
• a pressure insert disposed in the opening at the top end of the base, the pressure insert comprising a downward-facing surface configured to contact a head of the bone fastener, wherein the pressure insert is configured to apply a downward force on the head of the bone fastener when the rod is secured in the receiver.

An implantable receiver comprising:

• a body configured to be coupled to a bone fastener and a rod for spinal stabilization, the body comprising a longitudinal axis, wherein the body further comprises:
• a base defining an opening from a top end to a bottom end of the base, wherein a bottom axis of the bottom end of the base is obliquely angled with respect to the longitudinal axis;
• and
• a chamber defined within the base and in communication with the opening, wherein the chamber comprises an upper section, a lower section, and a tapered shoulder between the upper section and the lower section, wherein a chamber axis is obliquely angled with respect to the longitudinal axis;
• a retainer comprising a first portion and a second portion, wherein the retainer is disposed in the chamber between the upper section and lower section, wherein the retainer is configured to expand in the upper section of the chamber to receive a bulbous head of the bone fastener up through a bottom opening of the retainer, and wherein the first portion of the retainer is wider than the second portion of the retainer;
• a pressure insert disposed in the opening at the top end of the base, the pressure insert comprising a downward-facing surface configured to contact a head of the bone fastener, wherein the pressure insert is configured to apply a downward force on the head of the bone fastener when the rod is secured in the receiver;
• and
• a pin disposed in a pin hole in the body such that the pin extends into a slot in the pressure insert, wherein the pressure insert is pivotable about a longitudinal axis of the pin.

A modular bone fastener assembly, comprising:

• a bone fastener, comprising:
• a head comprising a spherical outer surface;
• a shaft extending downwardly from the head;
• and
• a neck disposed between the head and the shaft;
• and
• a receiver comprising:
• a body configured to be coupled to the bone fastener and a rod for spinal stabilization, the body comprising a longitudinal axis, wherein the body further comprises:
• a base defining an opening from a top end to a bottom end of the base, wherein a bottom axis of the bottom end of the base is obliquely angled with respect to the longitudinal axis;
• a chamber defined within the base and in communication with the opening, wherein the chamber comprises an upper section, a lower section, and a tapered shoulder between the upper section and the lower section, wherein a chamber axis is obliquely angled with respect to the longitudinal axis;
• and
• a channel oriented along the longitudinal axis, wherein a diameter of the channel is smaller than a diameter of the upper section of the chamber;
• a retainer comprising a upper portion and a lower portion, wherein the retainer is expandable around the head and disposed in the channel between the upper section and the lower section, and wherein the upper portion of the retainer is wider than the lower portion of the retainer;
• and
• a pressure insert disposed in the opening at the top end of the base, the pressure insert comprising a downward-facing surface configured to contact a part of the spherical outer surface of the head;
• and
• a set screw receivable within the channel, wherein the set screw is configured to apply a downward force on the rod to secure the rod within the channel and a downward force on the pressure insert and the head of the bone fastener to secure the head of the bone fastener within the receiver.

An implantable receiver comprising:

• a body configured to be coupled to a bone fastener and a rod for spinal stabilization, the body comprising a longitudinal axis, wherein the body further comprises:
• a base defining an opening from a top end to a bottom end of the base, wherein a bottom axis of the bottom end of the base is obliquely angled with respect to the longitudinal axis;
• a chamber defined within the base and in communication with the opening, wherein the chamber comprises an upper section, a lower section, and a tapered shoulder between the upper section and the lower section, wherein a chamber axis is obliquely angled with respect to the longitudinal axis;
• and
• a channel oriented along the longitudinal axis and configured to receive a set screw for locking the rod to the body, wherein a diameter of the channel is smaller than a diameter of the upper section of the chamber;
• and
• a retainer comprising a first portion and a second portion, wherein the retainer is disposed in the chamber between the upper section and the lower section, wherein the retainer is configured to expand in the upper section of the chamber to receive a bulbous head of the bone fastener up through a bottom opening of the retainer, wherein the first portion of the retainer is wider than the lower section of the chamber, and wherein the first portion of the retainer is wider than the second portion of the retainer, and wherein the first portion of the retainer is integral with the second portion of the retainer.