Polyaxial surgical screw and device for implanting said surgical screw
Inventors
Siccardi, Francesco • Fiechter, Meinrad • Riva, Marco • RAMPON, Marco
Assignees
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Publication Number
US-12336743-B2
Publication Date
2025-06-24
Expiration Date
Abstract
Various implementations include a polyaxial surgical screw and a device for implanting the screw. The screw comprises: an internally hollow tulip displaying a first open end for accessing inside the tulip, a second end opposite to the first end, and a side wall extending between the first and the second end; and a threaded shank displaying a first end defining the tip of the screw and a second end opposite to the first one displaying a ball joint joined to the second end of the tulip to orient said shank with respect to the tulip itself. The tulip also comprises at least one elongated rod projecting from the side wall and extending from the first end in a direction opposite to the second end.
Core Innovation
A polyaxial surgical screw is provided with an internally hollow tulip having a first open end and a second end, and a side wall extending between them. At least two elongated rods project from the side wall and extend from the first end in a direction opposite to the second end, with respective concave inner faces facing each other. A thread is formed on the concave inner faces near the tulip and on a cylindrical inner surface of the side wall, and a threaded shank with a ball joint joined to the tulip orientates the shank with respect to the tulip.
The implantation device includes a shaped tip for engaging the second end of the threaded shank to rotate the shank about its longitudinal extension axis, and a tubular body having a first end supporting the shaped tip and a second end opposite the first end configured to remain outside a patient's body. The tubular body defines two housing cavities spaced apart by two arched walls, and the arched walls define, in cooperation with outer surfaces of the elongated rods, a continuous cylindrical surface with a circular cross-section.
A rotation component of the shaped tip extends along the tubular body and is actuated by an operator, and the rotation component comprises an actuation cylinder extending through the tubular body and rotating inside the body itself. The rotation component further includes a bush having an outer surface that is at least partially threaded, housed inside the tubular body and defining a longitudinal through cavity for housing the actuation cylinder, with the bush attached to the actuation cylinder along a common longitudinal axis and rotatable relative to the cylinder about that axis.
After screw fixation, a manually held retaining element externally houses the protruding rods to enable later insertion of correction rods and locking bushes, and then the rods are extracted by breaking along weakening lines, leaving only the tulip and shank in the patient.
Claims Coverage
The document contains one independent claim defining the overall system, with dependent claims refining rod arrangement, rod cross-section geometry, interfaces, structural weakening and separation behavior, and operator-retained and actuation features. The independent claim includes multiple inventive features, chiefly the threaded concave rod interface with a hollow tulip and the implantation device that rotates the threaded shank via an internal actuation cylinder and a threaded bush engaging the rod threading.
Polyaxial surgical screw with hollow tulip and threaded concave rod interfaces
A polyaxial surgical screw having an internally hollow tulip with at least two elongated rods projecting from a side wall, where the rods have concave inner faces facing each other and a thread is formed on the concave inner faces near the tulip and on a cylindrical inner surface of the side wall, together with a threaded shank and a ball joint joined to the tulip to orient the shank with respect to the tulip.
Implantation device with shaped tip rotating the threaded shank
An implantation device comprising a shaped tip for engaging a second end of the threaded shank to rotate the shank about its own longitudinal extension axis, and a tubular body configured to remain outside a patient's body and defining housing cavities configured to engage the elongated rods, with a rotation component extending along the tubular body and actuated by an operator.
Tubular body with two spaced rod-engaging cavities and continuous cylindrical surface
The tubular body comprises two housing cavities spaced apart by two arched walls, with the arched walls defining, in cooperation with outer surfaces of the elongated rods, a continuous cylindrical surface with a circular cross-section.
Internal actuation cylinder and threaded bush engaging rod and tulip threads
The rotation component comprises an actuation cylinder extending through the tubular body and rotating inside the body itself, and a bush housed inside the tubular body defining a longitudinal through cavity for housing the actuation cylinder, where the bush has an outer surface that is at least partially threaded and is configured to be screwed onto the thread formed on the concave inner faces of the elongated rods and on the inner cylindrical surface of the polyaxial surgical screw, with the bush attached to the actuation cylinder along a common longitudinal axis and rotatable relative to the cylinder about that axis.
Across the independent claim and refinements reflected in dependent claims, the coverage centers on a polyaxial screw geometry with concave rod inner faces bearing thread that cooperates with a hollow tulip inner cylindrical surface, together with an implantation device whose shaped tip and internal actuation cylinder rotate the threaded shank. The tubular body uses two spaced housing cavities and arched walls to define a continuous cylindrical surface for engaging the rods, while a threaded bush screws onto the rod and tulip threads and is rotatable relative to the actuation cylinder to drive the engagement configuration.
Stated Advantages
Enables a system in which the implantation device engages and rotates the shank by cooperation of the shaped tip, actuation cylinder, and threaded bush.
Provides rod engagement via two housing cavities and arched walls that define a continuous cylindrical surface with a circular cross-section.
Provides an externally manually held retaining element for later insertion of correction rods and locking bushes.
Documented Applications
Minimally invasive implantation device for polyaxial spine surgery, with later insertion of correction rods and locking bushes following screw fixation.
Interested in licensing this patent?