Push-off driver and method for inserting bone screws
A method and device for inserting screws into a patient, such that when the device is removed the device does not stick to the screw. The device, being a push-off driver, may have a handle, an inner driver, and a threaded driver sleeve having a button mechanism and a plurality of spheres, and an inner sleeve. The method includes the steps of assembling a push-off driver attaching a bone screw to the push-off driver inserting the bone screw and detaching the bone screw from the driver by unthreading the threaded driver sleeve from the polyaxial screw which causes the spheres in the recess of the inner driver to back up against the start of the recess and causing the threaded driver sleeve to “push-off” the polyaxial screw from the inner driver.
1. A method of releasing a driver from a bone screw, the method comprising the steps of:
assembling a driver including a driver sleeve connectable at its distal end to the bone screw, wherein said driver sleeve comprises an inner driver sleeve, wherein said inner driver sleeve comprises spheres seated in bores, and an inner driver moveable inside the driver sleeve having a drive structure to drive the bone screw, said inner driver comprising recesses for receiving spheres of inner driver sleeve;
attaching the bone screw to the driver sleeve and inner driver;
inserting the bone screw into a patient; and
detaching the driver from the bone screw by unthreading the driver sleeve from the bone screw engaging an outer sleeve associated with a base portion with an inner driver, thereby coupling the inner driver to the outer sleeve, wherein the outer sleeve is released from or engaged with the inner driver by a button associated with the outer sleeve, wherein depressing said button allows spheres to move along bores and into or out of recesses.
2. The method of claim 1 , wherein assembling the driver comprises:
inserting the inner driver through a central channel of the driver sleeve such that the inner driver extends out a proximal end of the driver sleeve.
3. The method of claim 2 , wherein assembling the driver further comprises:
coupling a proximal end of the inner driver to a base portion of the driver, the base portion of the driver coupled to a handle.
4. The method of claim 3 , wherein assembling the driver further comprises:
rotatably fixing the inner driver with respect to the driver base portion.
5. The method of claim 3 , wherein assembling the driver further comprises:
engaging an outer sleeve associated with the base portion with the inner driver thereby coupling the inner driver to the outer sleeve, the inner driver received within a central channel of the outer sleeve, where the outer sleeve is engaged with the inner driver.
6. The method of claim 5 , wherein engaging the outer sleeve with the inner driver includes transitioning the outer sleeve between a release position and an engaged position.
7. The method of claim 6 , wherein transitioning the outer sleeve between the release position and the engaged position includes moving the outer sleeve in an axial direction along a longitudinal axis of the driver.
8. The method of claim 2 , wherein assembling the driver further comprises:
inserting the inner driver through a central channel of the driver sleeve such that a cross-pin provided at the distal end of the inner driver is accessible when the inner driver is coupled to the bone screw.
9. The method of claim 1 , wherein operating the button associated with the outer sleeve engages/disengages an engagement element associated with the outer sleeve with a corresponding engagement feature of the inner driver.
10. The method of claim 1 , wherein attaching the bone screw to the driver sleeve comprises threading the driver sleeve onto a head of the bone screw, the driver sleeve including a threaded distal end.
11. The method of claim 1 , wherein attaching the bone screw to the inner driver includes engaging a cross-pin provided at a distal end of the inner driver with a head of the bone screw to prevent rotation of the screw when attaching to the driver.
12. The method of claim 1 , wherein inserting the bone screw into the patient comprises rotating the inner driver within the driver sleeve.
13. The method of claim 1 , wherein detaching the driver from the bone screw further includes unthreading the driver sleeve from a head of the bone screw, the driver sleeve including a threaded distal end, wherein the unthreading of the driver sleeve disengages the inner driver from the bone screw.
14. The method of claim 1 , wherein detaching the driver from the bone screw further includes contacting the driver sleeve with a base portion of the driver to prevent axial movement of the driver sleeve as it is unthreaded from the bone screw, where the base portion of the driver is coupled to a proximal end of the inner driver.
15. The method of claim 14 , wherein as the driver sleeve is prevented from moving axially towards a proximal end of the driver, the drive structure of the inner driver is detached from the bone screw.
16. The method of claim 1 , further comprises disassembling the driver including the steps of:
releasing a proximal end of the inner driver from a base portion of the driver, the base portion coupled to a handle;
removing the inner driver from the base portion; and
removing the inner driver from the driver sleeve by sliding the inner driver out through a central channel provided in the driver sleeve.