Limb sparing in mammals using patient-specific endoprostheses and cutting guides.

Abstract

A method for performing surgery on a target bone with guidance from an adjacent bone adjacent to the target bone, the method using a cutting guide including a mounting portion, a cut guiding portion and a linking portion extending therebetween, the method comprising: mounting the mounting portion to the adjacent bone and positioning the cut guiding portion adjacent to the target bone, wherein the mounting portion and the cut guiding portion are positioned in a predetermined spatial relationship relative respectively to the adjacent and target bones; and making a cut in the target bone using a saw, the saw being guided along a predetermined path by the cut guiding portion.

What is claimed is: 
     
         1 . A method for performing surgery on a target bone with guidance from an adjacent bone adjacent to the target bone, the method using a cutting guide including a mounting portion, a cut guiding portion and a linking portion extending therebetween, the method comprising:
 mounting the mounting portion to the adjacent bone and positioning the cut guiding portion adjacent to the target bone, wherein the mounting portion and the cut guiding portion are positioned in a predetermined spatial relationship relative respectively to the adjacent and target bones; and   making a cut in the target bone using a saw, the saw being guided along a predetermined path by the cut guiding portion;   whereby the cutting guide is positioned relative to the target bone using a bone that differs from the target bone in which a cut is to be made.   
     
     
         2 . The method as defined in  claim 1 , wherein
 the cutting guide is delimited by a cutting guide peripheral surface defining a bone facing portion which faces the target bone and the adjacent bone when the cutting guide is operatively mounted thereto, the bone facing portion being contoured to match a shape of the target and adjacent bones; and   mounting the mounting portion and positioning the cut guiding portion includes abutting the cutting guide peripheral surface against the target and adjacent bones where the bone facing portion is contoured to match the shape of the target and adjacent bones so that the cutting guide is positioned at a predetermined location and a predetermined orientation relative to the target bone.   
     
     
         3 . The method as defined in  claim 2 , wherein the cutting guide defines a K-wire aperture for inserting a K-wire therethrough, the method further comprising inserting the K-wire though the K-wire aperture and into the target bone to secure the cutting guide to the target bone. 
     
     
         4 . The method as defined in  claim 2 , wherein the target bone is a radius and the adjacent bone is an ulna defining a styloid process. 
     
     
         5 . The method as defined in  claim 4 , wherein mounting the mounting portion including hooking the styloid process. 
     
     
         6 . The method as defined in  claim 1 , wherein making the cut excises a portion of the target bone, the method further comprising replacing the portion of the target bone with an endoprosthesis. 
     
     
         7 . The method as defined in  claim 6 , further comprising:
 imaging a contralateral bone contralateral to the target bone and forming a model of a part of the contralateral bone corresponding to the portion of the target bone; and   manufacturing the endoprosthesis, wherein the endoprosthesis includes a bone replica part thereof that is shaped like a mirror image of the model of the part of the contralateral bone.   
     
     
         8 . The method as defined in  claim 7 , wherein
 the target bone is a radius, the adjacent bone is an ulna and metacarpals are present distally to the radius and ulna;   manufacturing the endoprosthesis further includes providing a fixation shaft and a fixation plate extending from the bone replica opposed to each other;   replacing the portion of the target bone with the endoprosthesis includes inserting the fixation shaft in a medula of a remaining part of the radius after excision and fastening the fixation plate to the metacarpals.   
     
     
         9 . The method as defined in  claim 1 , wherein the cut guiding portion defines a slit extending therethrough for guiding the saw, making the cut including inserting a saw blade of the saw into the slit and cutting through the target bone with the saw blade inserted in the slit. 
     
     
         10 . The method as defined in  claim 1 , wherein the cut guiding portion defines at least one drilling guide aperture extending therethrough, the method further comprising drilling in the bone with a drill having a drill bit extending through the drilling guide aperture. 
     
     
         11 . The method as defined in  claim 1 , further comprising
 imaging the target bone and the adjacent bone;   forming a model of the shape of the target bone and the adjacent bone; and   manufacturing the cutting guide based on the model of the shape of the target bone and the adjacent bone so that the bone facing portion is contoured to conform to the shape of the target bone and the adjacent bone.   
     
     
         12 . The method as defined in  claim 11 , wherein manufacturing the cutting guide is performed through 3D printing. 
     
     
         13 . The method as defined in  claim 1 , wherein the target bone is affected by a tumour.