Fastener having torque optimized head

Abstract

Disclosed is a medical fastener that can be mounted to a bone of a patient. The medical fastener can include a head portion comprising a recess having a first portion, a second tapered portion extending from the first portion, and a third cylindrical portion extending from the second tapered portion. A threaded body portion can extend from the head portion. The first portion and the second portion can have a Torx geometry or star-shaped configuration. Also disclosed is a driver usable to mount the medical fastener to the bone. The driver can include a tip that is complementary to the recess and an end that enables the driver to mount to a drill or other device that can rotate the driver.

1 . A system for mounting a medical fastener to a bone of a patient, the system comprising:
 a driver of a first material comprising a tip having a first portion, a second tapered portion, and a pin having a substantially uniform cross-sectional profile extending from the second tapered portion, the first portion and the second tapered portion having a plurality of indentations and extensions disposed thereon that cooperatively form a fastener contact surface area extending across the first portion and second tapered portion to the pin of the driver; and   a medical fastener of a second material securely coupled to the driver, wherein the medical fastener comprises a head portion and a threaded body portion, the head portion having a recessed inner surface that receives the tip of the driver, the recessed inner surface comprising a first portion that includes a plurality of indentations and plurality of extensions, each of said plurality of indentations and extensions extending across the first portion, a second tapered portion tapering substantially inward and away from the first portion and toward a third cylindrical portion extending from the second tapered portion into the threaded body portion, the second tapered portion including a plurality of indentations and plurality of extensions, each of said plurality of indentations and extensions extending across the second tapered portion, the third cylindrical portion adapted to receive the pin, the third cylindrical portion having a substantially uniform cross-sectional profile that is smaller than the cross-sectional profile of the pin when separate, said first portion and second tapered portion of the recessed inner surface cooperatively forming a driver contact surface area extending across the first portion and second tapered portion to the third cylindrical portion of the recessed inner surface, wherein each of the first portion, the second tapered portion, and the third cylindrical portion of the recessed inner surface are configured to contact and engage with the first portion, the second tapered portion, and the pin of the driver to facilitate driving of the medical fastener by the driver, and wherein the first material is harder than the second material such that the pin of the driver deforms the third cylindrical portion of the recessed inner surface when disposed therein.   
     
     
         2 . The system as recited in  claim 1 , wherein the pin is disposed in the third cylindrical portion of the recessed inner surface such that the driver is securely coupled to the medical fastener. 
     
     
         3 . The system as recited in  claim 2 , wherein the pin interference fits with the third cylindrical portion of the recessed inner surface. 
     
     
         4 . The system as recited in  claim 2 , wherein at least a portion of the pin has a roughened surface. 
     
     
         5 . The system as recited in  claim 2 , wherein one or more portions of the tip interference fits with at least one of the first portion and the second portion of the medical fastener. 
     
     
         6 . The system as recited in  claim 1 , wherein the each of the driver and the medical fastener are sterilized and securely coupled to one another so as to reduce unwanted handling of the medical fastener and so as to maintain sterility of the medical fastener. 
     
     
         7 . The system as recited in  claim 1 , wherein the medical fastener has a Young's Modulus that is lower than that of the driver. 
     
     
         8 . The system as recited in  claim 1 , wherein the threaded body portion comprises a first end located adjacent to the head portion, a second end located distal to the first end, and a channel extending from the second end toward the first end the channel being positioned to collect particles from a hole receiving the threaded body portion. 
     
     
         9 . The system as recited in  claim 8 , wherein the channel comprises an open end at the second end of the threaded body portion. 
     
     
         10 . A system for mounting a medical fastener to a bone of a patient under substantially asceptic conditions, the system comprising:
 a driver comprised of a first material and a medical fastener comprised of a second material that has a Young's modulus lower than that of the first material, wherein each of the driver and the medical fastener are sterilized and securely coupled to one another so as to reduce unwanted handling of the medical fastener to maintain sterility of the medical fastener;   the driver comprising:
 a tip having a first portion, a second tapered portion, and a pin having a substantially uniform cross-sectional profile extending from the second tapered portion, the first portion and the second tapered portion having a plurality of indentations and extensions disposed thereon that cooperatively form a fastener contact surface area extending across the first portion and second tapered portion to the pin of the driver; 
   the medical fastener comprising:
 a head portion and a threaded body portion, the head portion having a recessed inner surface that receives the tip of the driver, the recessed inner surface comprising a first portion that includes a plurality of indentations and plurality of extensions, each of said plurality of indentations and extensions extending across the first portion, a second tapered portion tapering substantially inward and away from the first portion and toward a third cylindrical portion extending from the second tapered portion into the threaded body portion, the second tapered portion including a plurality of indentations and plurality of extensions, each of said plurality of indentations and extensions extending across the second tapered portion, the third cylindrical portion adapted to receive the pin, the third cylindrical portion having a substantially uniform cross-sectional profile that is smaller than the cross-sectional profile of the pin when separate, said first portion and second tapered portion of the recessed inner surface cooperatively forming a driver contact surface area extending across the first portion and second tapered portion to the third cylindrical portion of the recessed inner surface, wherein each of the first portion, the second tapered portion, and the third cylindrical portion of the recessed inner surface are configured to contact and engage with the first portion, the second tapered portion, and the pin of the driver to facilitate driving of the medical fastener by the driver, and wherein the first material is harder than the second material such that the pin of the driver deforms the third cylindrical portion of the recessed inner surface when disposed therein. 
   
     
     
         11 . The system as recited in  claim 10 , wherein the pin is disposed in the third cylindrical portion of the recessed inner surface such that the driver is securely coupled to the medical fastener. 
     
     
         12 . The system as recited in  claim 11 , wherein the pin interference fits with the third cylindrical portion of the recessed inner surface. 
     
     
         13 . The system as recited in  claim 11 , wherein at least a portion of the pin has a roughened surface. 
     
     
         14 . The system as recited in  claim 11 , wherein one or more portions of the tip interference fits with at least one of the first portion and the second portion of the medical fastener. 
     
     
         15 . The system as recited in  claim 11 , wherein the threaded body portion comprises a first end located adjacent to the head portion, a second end located distal to the first end, and a channel extending from the second end toward the first end the channel being positioned to collect particles from a hole receiving the threaded body portion. 
     
     
         16 . The system as recited in  claim 15 , wherein the channel comprises an open end at the second end of the threaded body portion.