Screw fixation method

Abstract

A method for fixing a bone graft on a shoulder bone includes, before selection and use of a fixation device, a preoperative plan including collecting a preoperative imaging of a shoulder of a patient; virtually 3D modeling the shoulder; identifying at least one anatomical structure; and preoperative planning by one of sizing the graft, positioning the graft on the host bone, positioning the fixation device, and/or selecting the fixation device.

1 . A method for fixing a bone graft on a shoulder bone, the method comprising, before selection and use of a fixation device, a preoperative plan including the following operations:
 collecting a preoperative imaging of a shoulder of a patient by radiography and/or ultrasound and/or CT image and/or MRI of the shoulder;   virtually 3D modeling the shoulder;   identifying at least one anatomical structure; and   preoperative planning of at least one of the following operations: sizing the graft, positioning the graft on the host bone, positioning the fixation device, and selecting the fixation device.   
     
     
         2 . The fixation method according to  claim 1 , wherein the method further comprises the following operations: displaying during surgical intervention the preoperative plan on an augmented or mixed reality device. 
     
     
         3 . The fixation method according to  claim 2 , wherein the operations of displaying during the surgical intervention the preoperative plan on an augmented or mixed reality device comprises overlaying the preoperative plan onto a corresponding patient bone. 
     
     
         4 . The fixation method according to  claim 2 , wherein the operations of displaying during the surgical intervention the preoperative plan on an augmented or mixed reality device comprises overlaying the preoperative plan onto a corresponding patient bone and guiding at least one of the following operations: sizing the graft, positioning the graft on the host bone, positioning the fixation device and selecting the fixation device. 
     
     
         5 . The fixation method according to  claim 1 , wherein the fixation device is comprised of two screws and only two screws. 
     
     
         6 . The fixation method according to  claim 5 , wherein at least one of the two screws comprises a cannula, where the at least one of the two screws is provided with a longitudinal through hole. 
     
     
         7 . The fixation method according to  claim 1 , wherein the fixation device is comprised of two screws and only two screws, comprising:
 a first screw provided at a proximal end with a head for compressing a bone by an end-abutment; and   a second screw provided at a distal end with a bone threading having a first helix pitch and at a proximal end with a bone threading having a helix with a pitch smaller than the first helix pitch, the second screw being headless.   
     
     
         8 . The fixation method according to  claim 7 , wherein the method further comprises, after the preoperative planning step, using the first and second screws to position the bone graft on the host bone and fix the bone graft on the shoulder. 
     
     
         9 . The fixation method according to  claim 1 , wherein the method further comprises, after the preoperative planning step, using the fixation device to position the bone graft on the host bone and fix the bone graft on the shoulder. 
     
     
         10 . The fixation method according to  claim 9 , wherein the method further comprises the following operations: displaying during surgical intervention the preoperative plan on an augmented or mixed reality device. 
     
     
         11 . The fixation method according to  claim 10 , wherein the operations of displaying during the surgical intervention the preoperative plan on an augmented or mixed reality device comprises overlaying the preoperative plan onto a corresponding patient bone. 
     
     
         12 . The fixation method according to  claim 10 , wherein the operations of displaying during the surgical intervention the preoperative plan on an augmented or mixed reality device comprises overlaying the preoperative plan onto a corresponding patient bone and guiding at least one of the following operations: sizing the graft, positioning the graft on the host bone, positioning the fixation device and selecting the fixation device. 
     
     
         13 . The fixation method according to  claim 9 , wherein the fixation device is comprised of two screws and only two screws. 
     
     
         14 . The fixation method according to  claim 13 , wherein at least one of the two screws comprises a cannula, where the at least one of the two screws is provided with a longitudinal through hole. 
     
     
         15 . The fixation method according to  claim 9 , wherein the fixation device is comprised of two screws and only two screws, comprising:
 a first screw provided at a proximal end with a head for compressing a bone by an end-abutment; and   a second screw provided at a distal end with a bone threading having a first helix pitch and at a proximal end with a bone threading having a helix with a pitch smaller than the first helix pitch, the second screw being headless.