Minimally invasive intervertebral rod insertion

A method of planning an intervertebral rod insertion procedure, comprising:

• receiving a preoperative surgical plan defining positions and orientations for inserting screws into a plurality of vertebrae of a subject's spine as well as a target curvature profile, each of the screws having a head;
• calculating a shape of a rod that will connect the heads of the screws;
• determining whether one or more osteotomies are required to permit percutaneous insertion of the rod, such that manipulation of a proximal end of the rod having the calculated shape enables a distal end of the rod to pass sequentially through the heads of the screws;
• when no osteotomy is required:
• providing instructions for insertion of the screws in the defined positions and orientations,
• providing information for forming the rod having the calculated shape, and
• providing instructions for insertion of the rod;
• or
• when one or more osteotomies are required:
• adjusting the plan by updating at least one of the position and orientation of at least one of the screws to yield an updated screw configuration;
• recalculating the shape of the rod to match the updated screw configuration;
• determining whether each of the one or more osteotomies is still required to permit percutaneous insertion of the rod have the recalculated rod shape;
• and
• repeating the steps of adjusting the plan and recalculating the rod shape until fewer than all of the one or more osteotomies are required to permit percutaneous insertion of the rod having the recalculated rod shape.

A system for planning an intervertebral rod insertion procedure, comprising:

• a robot whose position is known relative to a subject's vertebrae;
• and
• a control system configured to:
• receive a preoperative surgical plan comprising a planned position and orientation for insertion of each of a plurality of screws into vertebrae of a subject's spine to achieve a target curvature profile of the subject's spine, each of the screws having a head;
• calculating a rod shape that will enable a rod to connect the heads of the plurality of screws;
• determining, using a path planning algorithm, whether performance of one or more osteotomies is required to permit percutaneous insertion of the rod having the rod shape, such that manipulation of a proximal end of the rod having the rod shape enables a distal end of the rod to pass sequentially through the heads of the screws;
• and
• when performance of one or more osteotomies is required:
• adjusting the plan by updating at least one of the position and orientation of at least one screw of the plurality of screws to yield an adjusted plan with an updated screw configuration;
• calculating an updated rod shape to match the updated screw configuration;
• determining, using the path planning algorithm and based on the adjusted plan and the updated rod shape, whether performance of each of the one or more osteotomies is still required to permit percutaneous insertion of the rod;
• repeating the steps of adjusting the plan and calculating the updated rod shape until performance of at least one osteotomy of the one or more osteotomies is not required to permit percutaneous insertion of the rod;
• and
• causing the robot to insert the screws in the updated screw configuration or to insert the rod having the updated rod shape.