Computer-aided three-dimensional bending of spinal rod implants, other surgical implants and other articles, systems for three-dimensional shaping, and apparatuses therefor

Abstract

An implantable rod can be bent three-dimensionally in an automated system, which is especially useful for pre-surgical formation of implantable spinal rods. When local and/or global feedback processing accompanies a series of shaping steps automatically imposed on a rod or other article being shaped into three-dimensional form, formation time may be expedited compared to manual creation, and shapes difficult or impractical to create manually may be constructed simply.

1 . An automated system that bends a rod, comprising: 
 an input mechanism for producing a desired three-dimensional bent shape;    a translational control interface; and    automated rod-bending hardware, wherein the automated rod-bending hardware imposes a series of local bends in the rod until the desired three-dimensional bent shape has been formed.    
   
   
       2 . The rod-bending system of  claim 1 , wherein the rod is a medically implantable rod of less than about 1 cm diameter.  
   
   
       3 . The rod-bending system of  claim 1 , wherein the input mechanism is selected from the group consisting of (1) deforming a deformable template rod into the desired three-dimensional bent shape followed by photographic scanning of the deformed template rod; (2) operating a spatial locator to map a region where the desired three-dimensional bent shape is to be implanted; (3) computer-aided design of a virtual rod; (4) operating a surgical imaging apparatus; and (5) imaging pedicle screws to establish the desired three-dimensional bent shape.  
   
   
       4 . The rod-bending system of  claim 1 , including real-time automated correction of local bends for spring-back.  
   
   
       5 . The rod-bending system of  claim 1 , including a sensor operating at a region where a local bend has just been imposed, information from the sensor being subjected to at least one of a local feedback operation and a global feedback operation.  
   
   
       6 . The rod-bending system of  claim 5 , including information from the sensor being subjected to both a local feedback operation and a global feedback operation.  
   
   
       7 . The rod-bending system of  claim 5 , wherein as a result of the feedback operation(s), a current sequence of applicable automated instructions for bending is automatically modified into a modified sequence of automated instructions for bending.  
   
   
       8 . The rod-bending system of  claim 7 , wherein feedback is used to impose additional bending actuation at the same location to achieve desired local bending accuracy.  
   
   
       9 . The automated system of  claim 1 , wherein in imposition by the automated rod-bending hardware of the series of local bends in the rod, the automated rod-bending hardware provides higher repeatability than could be provided by a human operator manually attempting to execute a same series of local bends.  
   
   
       10 . The automated system of  claim 1 , including after each imposition of a local bend, automated global feedback wherein an actual local bend imposed is automatically compared to the desired shape and instructions for remaining bending steps are automatically evaluated.  
   
   
       11 . The automated system of  claim 1 , including an automated cutting mechanism that reduces the rod to a desired length.  
   
   
       12 . The automated system of  claim 1 , including, after a first set of automated instructions for imposing a series of local bends has been formulated but in advance of implementing the first set of automated instructions, an automated screening of whether sufficient clearance is physically present to justify initiating the first set of automated instructions.  
   
   
       13 . The automated system of  claim 1 , including, prior to each imposition of a local bend according to a bend imposition instruction, an automated screening of whether sufficient clearance is physically present to justify ordering execution of the bend imposition instruction.  
   
   
       14 . The automated system of  claim 1 , including an automated correction system which, when bend imposition has been proceeding along the rod according to a first set of instructions for imposing local bends with the first set of instructions being only partly executed, the automated correction system (1) detects a point at which small errors in imposed bends have accumulated to a point where the first set of instructions cannot viably be completed as a matter of physical clearance and (2) revises the first set of instructions to a second set of instructions, wherein the second set of instructions can be viably completed as a matter of physical clearance.  
   
   
       15 . The automated system of  claim 1 , wherein the rod being bent is made of a material selected from the group consisting of: titanium; titanium alloy; steel and shape-memory alloys.  
   
   
       16 . The automated system of  claim 1 , including one of: (a) a motorized system responsible for forward movement of the rod including stopping according to a series of actuator commands, the actuator commands being computer-generated; or (b) a motorized system responsible for forward movement of the rod-bending hardware including stopping according to a series of actuator commands, the actuator commands being computer-generated.  
   
   
       17 . The automated system of  claim 1 , including one of: (a) a motorized system responsible for rotary movement of the rod including stopping according to a series of actuator commands, the actuator commands being computer-generated; or (b) a motorized system responsible for rotary movement of the rod-bending hardware including stopping according to a series of actuator commands, the actuator commands being computer-generated.  
   
   
       18 . An automated method of making an implantable rod, comprising: 
 non-manual imposition of a series of local bends in an implantable rod, whereby a three-dimensional bent shape is non-manually formed.    
   
   
       19 . The rod-making method of  claim 18 , wherein following imposition of a local bend, at least one feedback loop is operated, with the feedback loop selected from the group consisting of local feedback and global feedback, and with the feedback loop being machine-implemented and human-free.  
   
   
       20 . The rod-making method of  claim 18 , including at least one automated step of translating a desired bent-shape into a series of actuator commands for machine-based rod-bending.  
   
   
       21 . The rod-making method of  claim 20 , including actuator command implementation, resulting in machine-imposed bending of the rod.  
   
   
       22 . The rod-making method of  claim 21 , including automated imposition of at least one three-dimensional bend approaching 180 degrees or automated imposition of a sequence of bends whose combined effect is a three-dimensional bend approaching 180 degrees.  
   
   
       23 . The rod-making method of  claim 18 , including, after automated imposition of a local bend in the rod, operation of both automated local feedback and automated global feedback.  
   
   
       24 . The rod-making method of  claim 18 , wherein the three-dimensional bent shape is constructed before surgical exposure of the patient's spine.  
   
   
       25 . The rod-making method of  claim 18 , including non-manually forming a customized bent rod shape corresponding to a spine of a particular patient having scoliosis.  
   
   
       26 . The rod-making method of  claim 18 , wherein rod-bending is entirely automated and the rod needs no manual shaping before being implanted in the patient.  
   
   
       27 . The rod-making method of  claim 18 , including: 
 determining X-Y-Z coordinates of a desired rod shape;    integrated feedback processing a local bend that has been imposed.    
   
   
       28 . The rod-making method of  claim 18 , including operating an automatic controller commanding operations performed on the rod, the controller including: 
 a feed command for feeding movement of the rod;    a rotate command for rotating movement of the rod; and    a bend command for bending movement of the rod.    
   
   
       29 . The rod-making method of  claim 18 , including measuring spring-back of the rod via an automatic sensor.  
   
   
       30 . The rod-making method of  claim 18 , including collecting spring-back measurements via an automatic sensor and automated processing of the spring-back measurements.  
   
   
       31 . The rod-making method of  claim 18 , including a step of computer-assisted design of a desired three-dimensional bent shape.  
   
   
       32 . The rod-making method of  claim 31 , wherein the desired three-dimensional bent shape is actually constructed.  
   
   
       33 . The rod-making method of  claim 31 , including, as rod-bending progresses, performing a series of automated comparisons of the bent rod as actually-bent to the desired three-dimensional shape.  
   
   
       34 . The rod-making method of  claim 18 , wherein bends are imposed non-manually along the rod in one-direction progression without doubling-back.  
   
   
       35 . The rod-making method of  claim 18 , including an automated step in which is determined an end of the rod at which to begin imposing bends.  
   
   
       36 . The rod-making method of  claim 18 , including disposing the rod in an automated bending system and before bending is permitted to begin, an automated step is performed of processing a desired shape to be constructed to confirm or deny sufficient clearance for automated bending to successfully proceed.  
   
   
       37 . A method of making a rod, comprising: 
 (a) an automated series of non-manual bending steps on a rod, wherein each bending step imposes an actual bend on the rod;    (b) after a bending step, (i) automatic local feedback processing wherein data representing the actual bend is processed for whether the actual bend is according to instruction or varies from instruction; and (ii) automatic global feedback processing wherein data representing the actual bend is processed for formulating at least one next instruction for a bending step downstream along the rod.    
   
   
       38 . The method of  claim 37 , wherein the information from (b)(i) is used to further impose bending actuation to reach the desired bending angle, either in a single step or in a sequence of steps, either by using an analytical estimate of spring-back based on material properties or based on measurements from previous bends.  
   
   
       39 . The rod-making method of  claim 37 , wherein the rod is an implantable rod.  
   
   
       40 . The rod-making method of  claim 39 , wherein a three-dimensionally bent rod is formed.  
   
   
       41 . The rod-making method of  claim 39 , wherein the rod is of titanium or a titanium alloy, and has a diameter of less than about 1 cm.  
   
   
       42 . The rod-making method of  claim 39 , wherein the three-dimensionally bent rod includes at least one severe bend approaching 180 degrees.  
   
   
       43 . An implantable-rod bending apparatus, comprising: 
 a housing receiving an implantable-rod to which bending force is to be applied; and    a fully-automated mechanical system that applies bending force to the rod disposed in the housing and that positions the rod disposed in the housing, including means for positioning, orienting and bending the rod into a three-dimensional bent shape.    
   
   
       44 . The apparatus of  claim 43 , wherein the automated mechanical system that applies bending force can apply bending force approaching imposition of a 180 degree bend to the rod.  
   
   
       45 . The apparatus of  claim 43 , wherein the apparatus includes a minimal clearance that is a void volume such that the rod may be as long as about 1 yard and may be bent while disposed in the apparatus into a three-dimensional bent shape.  
   
   
       46 . An automated rod-bending system, comprising: 
 a housing receiving an implantable-rod to which bending force is to be applied; and    a fully-automated mechanical system that applies bending force to the rod disposed in the housing and that positions the rod disposed in the housing, including means for positioning, orienting and bending the rod into a three-dimensional bent shape;    a fully automated control system that delivers a series of computer-readable instructions to the fully-automated mechanical system that applies bending force and that positions the rod.    
   
   
       47 . The automated rod-bending system of  claim 46 , including a sensor from which is obtained digitized information quantifying bending actually present in the rod.  
   
   
       48 . The automated rod-bending system of  claim 47 , including, after imposition of each bend, processing data from the sensor according to at least one or both of automated local feedback and automated global feedback.  
   
   
       49 . The automated rod-bending system of  claim 48 , including, after imposition of each bend, both automated local feedback and automated global feedback.  
   
   
       50 . A surgical method, comprising steps of: 
 automated bending of a rod into a three-dimensional bent shape implantable in a patient;    surgical implantation into the patient of the three-dimensional bent shape.    
   
   
       51 . The method of  claim 50 , wherein the three-dimensional bent shape is implanted in a spinal region of the patient.  
   
   
       52 . The method of  claim 51 , wherein the surgical implantation is for treating scoliosis.  
   
   
       53 . The method of  claim 51 , wherein the three-dimensional bent shape is constructed and ready for implantation before surgical exposure of the patient's spine.  
   
   
       54 . The method of  claim 50 , including in advance of surgical implantation, automated pre-screening of the three-dimensional bent shape, including a determination of placement in the patient of the three-dimensional bent shape with reference to cooperating hardware placed, or to be placed, in the patient.  
   
   
       55 . A method of making an implantable article, comprising steps of: 
 automated shaping of an article, in a direction of a target design that is a three-dimensional bent shape implantable in a patient, including a series of automated shaping steps each imposing an actual local shape;    after each automated shaping step wherein an actual local shape is imposed, automated global feedback wherein the actual local shape imposed is automatically compared to the target design and instructions for remaining shaping steps are automatically evaluated.    
   
   
       56 . The method of  claim 55 , including automatic adjustment of instructions for at least one automated shaping step still to be performed.  
   
   
       57 . The method of  claim 55 , including automated local feedback wherein the actual local shape imposed is automatically compared to instructions given and additional actuation is imposed to the same local area of the article to improve the agreement between the desired local shape and the achieved local shape.  
   
   
       58 . The method of  claim 55 , wherein the implantable article is a rod.  
   
   
       59 . The method of  claim 55 , wherein the implantable article is formed in less time via the automated shaping than could be accomplished by being manually formed.  
   
   
       60 . A pedicle screw cap, comprising an article having an opening which receives a pedicle screw, the article being biocompatible and of a medically-imageable material.  
   
   
       61 . The pedicle screw cap of  claim 60 , wherein the screw cap has a shape that accentuates its position and orientation to surgical imaging apparatus.  
   
   
       62 . The automated system of  claim 1 , wherein the input mechanism for producing a desired three-dimensional bent shape includes at least one of: in vivo medical imaging or in vivo biological imaging.  
   
   
       63 . The automated system of  claim 1 , wherein the hardware comprises a bending mandrel and a bending arm.  
   
   
       64 . The automated system of  claim 63 , wherein the bending arm is disposed in a rolling sleeve.