Fastener insertion method

Abstract

A method may include rotating a threaded fastener at a first rotational speed to provide a kinetic energy force component for the fastener based on the first rotational speed and driving the fastener into a structure based on the rotating. The structure may provide a torsional resistance during the driving greater than a torsional strength of the fastener. The driving may provide a torque force component applied to the fastener. The driving may cut threads into the structure with the fastener. The driving may apply a total force to the structure from the fastener including the kinetic energy force component and the torque force component. The total force applied by the fastener may be greater than or equal to a force required for the cutting. The torque force component may be less than a torsional strength of the fastener.

1 . A method comprising:
 rotating a threaded fastener at a first rotational speed, said rotating providing a kinetic energy force component for the fastener based on the first rotational speed;   driving the fastener into a structure based on said rotating, said structure providing a torsional resistance during said driving greater than a torsional strength of the fastener and said driving providing a torque force component applied to the fastener; and   cutting threads into the structure with the fastener based on said driving, said driving applying a total force to the structure from the fastener including the kinetic energy force component and the torque force component, wherein the total force applied by the fastener is greater than or equal to a force required for said cutting and the torque force component is less than the torsional strength of the fastener.   
     
     
         2 . The method of  claim 1 , wherein the structure includes bone. 
     
     
         3 . The method of  claim 2 , wherein the fastener is formed from one of a polymer, a metal, a biocompatible non-resorbable material, a biocompatible resorbable material, a ceramic, a composite material, an allograft and a xenograft. 
     
     
         4 . The method of  claim 1 , further comprising terminating said driving when a predetermined torque limit is applied to the fastener. 
     
     
         5 . The method of  claim 4 , wherein one of the fastener and the driver includes a torque limiting feature that produces said terminating when an engagement between the fastener and the structure provides a frictional force between the fastener and the structure resulting in a torque that is greater than the predetermined torque limit. 
     
     
         6 . The method of  claim 5 , wherein the frictional force includes an engagement between a head of the fastener and the structure. 
     
     
         7 . The method of  claim 1 , further comprising forming a pilot hole having a first diameter greater than a minor diameter of the fastener and less than a major diameter of the fastener, said driving including driving the fastener into the pilot hole. 
     
     
         8 . The method of  claim 7 , wherein a frictional force is applied to the threads of the fastener as the fastener is driven into the structure, the total force applied by the fastener being greater than the force required for said cutting and the frictional force. 
     
     
         9 . The method of  claim 1 , wherein said driving includes drilling a hole in the structure. 
     
     
         10 . The method of  claim 9 , wherein a drilling force is applied to the fastener as the fastener is driven into the structure, the total force applied by the fastener being greater than the force required for said cutting and said drilling. 
     
     
         11 . The method of  claim 1 , wherein the first rotational speed is at least 12,000 revolutions per minute. 
     
     
         12 . A method comprising:
 applying a kinetic energy force component to a fastener having a torsional strength by rotating the fastener at a first rotational speed;   applying a torque force component to the fastener;   driving the fastener into a structure based on the combination of the kinetic energy and torque force components, wherein the torsional resistance provided by the structure during said driving is greater than a torsional strength of the fastener and the torque force component is less than the torsional strength of the fastener during said driving; and   terminating said driving when the fastening portion is inserted a predetermined amount into the structure.   
     
     
         13 . The method of  claim 12 , wherein said terminating occurs when an additional torque force component is applied to the fastener based on a frictional engagement between a head of the fastener and the structure. 
     
     
         14 . The method of  claim 12 , wherein the structure includes bone. 
     
     
         15 . The method of  claim 14 , wherein the fastener is formed from one of a polymer, a metal, a biocompatible non-resorbable material, a biocompatible resorbable material, a ceramic, a composite material, an allograft and a xenograft. 
     
     
         16 . The method of  claim 12 , further comprising forming a pilot hole having a first diameter greater than a minor diameter of the fastener and less than a major diameter of the fastener, said driving including driving the fastener into the pilot hole. 
     
     
         17 . The method of  claim 16 , wherein a frictional force is applied to the threads of the fastener as the fastener is driven into the structure, the combination of the kinetic energy and torque force components of the fastener being greater than the force required for said cutting and the frictional force. 
     
     
         18 . The method of  claim 12 , wherein said driving includes drilling a hole in the structure. 
     
     
         19 . The method of  claim 18 , wherein a drilling force is applied to the fastener as the fastener is driven into the structure, the combination of the kinetic energy and torque force components of the fastener being greater than the force required for said cutting and said drilling. 
     
     
         20 . The method of  claim 12 , wherein the first rotational speed is at least 12,000 revolutions per minute. 
     
     
         21 . An apparatus comprising:
 a threaded fastener having a torsional strength; and   a driver engaged with and adapted to drive said fastener at a first rotational speed into a structure and apply a torque force component to said fastener, said fastener adapted to have a kinetic energy force component based on the first rotational speed and to apply a total force to the structure including the torque force component and the kinetic energy force component that cuts threads into the structure, wherein the total force is greater than or equal to a force required to cut the threads and the torque force component is less than the torsional strength of said fastener.