Medical device and method to correct deformity

Abstract

A system for correcting a spinal deformity includes an implant fixed to one side of a vertebra and a rod extending along an axis of the spine on a second side of the vertebra. An adjustment member, which may include a reel, is coupled to the rod. A force directing member, such as a cable, extends between the rod and the adjustment member. The force directing member is retractable toward and extendible from the adjustment member. A method of correcting spinal deformity includes providing an implant, a rod, an adjustment member coupled to the rod, and a force directing member extending between the rod and the adjustment member. The adjustment member can be retractable toward and extendible from the adjustment member.

1 . A system for correcting an abnormal curvature of the spine, the system comprising:
 a proximal attachment anchor configured for fixation to a proximal vertebra, wherein the proximal vertebra is located at a cephalad end of a spinal curvature to be corrected;   a distal attachment anchor configured for fixation to a distal vertebra, wherein the distal vertebra is located at a caudal end of the spinal curvature to be corrected;   a rod adapted to extend between, and be coupled to, the proximal and distal attachment anchors;   an implant configured for fixation to a vertebra, wherein the vertebra is positioned along a spinal column between the proximal vertebra and the distal vertebra;   an adjustment member coupled to the rod and comprising a driving element; and   a flexible force directing member;
 wherein the flexible force directing member comprises a first end coupled to the adjustment member, a second end at least indirectly coupled to the implant, and a length extending between the implant and the adjustment member, 
 wherein the flexible force directing member is configured to exert a force on the vertebra when the length is shortened, and 
 wherein the adjustment member is configured to adjust the length. 
   
     
     
         2 . The system of  claim 1 , wherein the implant is configured for fixation to a plurality of vertebrae. 
     
     
         3 . The system of  claim 1 , wherein the adjustment member is configured to adjust the length over time. 
     
     
         4 . The system of  claim 1 , wherein a location of coupling the proximal attachment anchor to the rod and a location of coupling the distal attachment anchor to the rod are adjustable over time. 
     
     
         5 . The system of  claim 1 , wherein the adjustment member is configured to adjust the length of the flexible force directing member noninvasively. 
     
     
         6 . The system of  claim 5 , wherein the adjustment member further comprises a gear and a reel; and wherein
 the first end of the flexible force directing member is coupled to the reel;   the driving element is configured to actuate the gear;   the gear is configured to spin the reel; and   the reel is configured to adjust the length of the flexible force directing member.   
     
     
         7 . The system of  claim 5 , wherein the driving element comprises a motor and the adjustment member further comprises an implantable power supply configured to power the motor. 
     
     
         8 . The system of  claim 7 , wherein the motor is configured to adjust the length of the flexible force directing member at a programmed rate. 
     
     
         9 . The system of  claim 7 , wherein the motor comprises a stepper motor configured to adjust the length of the flexible force directing member in incremental amounts over time. 
     
     
         10 . The system of  claim 7 , wherein the adjustment member further comprises a sensor, and the motor is configured to maintain a programmed tension in the flexible force directing member. 
     
     
         11 . The system of  claim 5 , wherein the driving element comprises an electric motor configured for remote actuation by an external energy source. 
     
     
         12 . The system of  claim 11 , wherein the external energy source is selected from the group consisting of: an HF transmission coil, an RF energy transmitter, and a magnetic energy transmitter. 
     
     
         13 . The system of  claim 5 , wherein the driving element comprises a spring configured to exert gradual forces on the flexible force directing member. 
     
     
         14 . The system of  claim 1 , wherein the system comprises a plurality of said implants, a plurality of said adjustment members, and a plurality of said flexible force directing members. 
     
     
         15 . The system of  claim 1 , wherein the rod is adjustable in length. 
     
     
         16 . A method of correcting an abnormal curvature of the spine, the method comprising:
 affixing a proximal attachment anchor to a proximal vertebra, wherein the proximal vertebra is located at a cephalad end of a spinal curvature to be corrected;   affixing a distal attachment anchor to a distal vertebra, wherein the distal vertebra is located at a caudal end of the spinal curvature to be corrected;   positioning a rod so that it extends between the proximal and distal attachment anchors;   coupling the rod to the proximal and distal attachment anchors;   affixing an implant to a vertebra, wherein the vertebra is positioned along a spinal column between the proximal vertebra and the distal vertebra;   securing an adjustment member to a position along the rod;   positioning a flexible force directing member such that a portion of the flexible force directing member extends from the adjustment member to the implant, wherein the portion extending from the adjustment member to the implant defines a length; and   adjusting the length, using a driving element, to exert a force on the vertebra.   
     
     
         17 . The method of  claim 16 , wherein adjusting the length is repeated over time. 
     
     
         18 . The method of  claim 16 , wherein the length is adjusted noninvasively. 
     
     
         19 . The method of  claim 16 , wherein the step of adjusting the length comprises spinning a reel, around which at least an end of the flexible force directing member is positioned, by actuating a gear using the driving element. 
     
     
         20 . The method of  claim 16 , wherein the driving element comprises a motor which is powered by an implanted power supply. 
     
     
         21 . The method of  claim 16 , wherein the length is adjusted to a programmed tension in the flexible force directing member. 
     
     
         22 . The method of  claim 16 , wherein the driving element comprises an electric motor which is remotely actuated by an external energy source. 
     
     
         23 . The method of  claim 16 , wherein the driving element comprises a spring. 
     
     
         24 . The method of  claim 16 , wherein the driving element comprises a manually adjustable element. 
     
     
         25 . The method of  claim 16 , further comprising adjusting a position of the adjustment member along the rod after a period of time to accommodate positional changes of the vertebra relative to the rod. 
     
     
         26 . The method of  claim 16 , further comprising adjusting a vertical length of the rod after a period of time to adapt the rod to a straightening and lengthening of the spine. 
     
     
         27 . The method of  claim 16 , further comprising adjusting a location of coupling the proximal attachment anchor to the rod and a location of coupling the distal attachment anchor to the rod after a period of time to adapt the rod to a straightening and lengthening of the spine.