Patient-Specific Surgical Guidance Tool and Method of Use

Abstract

Presented is a preoperatively designed guidance tool for intraoperative use during bone or joint surgery wherein the guidance tool is specific to the anatomy of the patient being treated. The guidance tool comprises a body portion, a mating surface provided on the body portion for positioning the guidance tool on a corresponding registration surface of a patient's anatomy. The guidance tool further comprises at least one guide mechanism provided on the body portion for guiding a medical instrument at one or more preoperatively defined trajectories relative to a patient's anatomy. In the event of misalignment, the at least one guide mechanism is adjustable to alter the one or more preoperatively defined trajectories if necessary during intraoperative use. Also presented is a preoperative process for designing the guidance tool.

1 . A preoperatively designed guidance tool for intraoperative use during bone or joint surgery wherein said guidance tool is specific to the anatomy of the patient being treated, said guidance tool comprising:
 a body portion;   a mating surface provided on said body portion, said mating surface for positioning said guidance tool on a corresponding registration surface of a patient's anatomy; and   at least one guide mechanism provided on said body portion, said at least one guide mechanism for guiding at least one medical instrument at one or more preoperatively defined trajectories relative to a patient's anatomy;   wherein said at least one guide mechanism is adjustable to alter the one or more preoperatively defined trajectories if necessary during intraoperative use.   
     
     
         2 . The guidance tool of  claim 1 , wherein said body portion comprises a guide component, and a registration component, each of said at least one guide mechanism and said mating surface being provided on at least one of said guide component and said registration component. 
     
     
         3 . The guidance tool of  claim 2 , wherein said body portion further comprises a stability component. 
     
     
         4 . The guidance tool of  claim 1 , wherein said mating surface comprises a profile that is complementary to characteristic anatomical landmarks found on said registration surface of a patient's anatomy. 
     
     
         5 . The guidance tool of  claim 1 , further comprising a removable verification tool for mechanically verifying the correct position of the guidance tool on the patient's anatomy, having regard to preoperatively selected anatomical landmarks. 
     
     
         6 . The guidance tool of  claim 5 , wherein said verification tool is configured for insertion into said guide mechanism. 
     
     
         7 . The guidance tool of  claim 5 , wherein said verification tool comprises at least one graduated section to determine misalignment of the guidance tool relative to said one or more preoperatively defined trajectories. 
     
     
         8 . The guidance tool of  claim 7 , wherein said verification tool comprises two graduated sections for providing misalignment values relative to the patient's anatomy, a first graduated section providing misalignment values in a longitudinal direction, and a second graduated section providing misalignment values in a radial direction. 
     
     
         9 . The guidance tool of  claim 5 , further comprising locking keys provided on said body portion for aligning said verification tool in a preoperatively defined position for comparison with previously selected anatomical landmarks. 
     
     
         10 . The guidance tool of  claim 1 , wherein said guide mechanism comprises a guide channel and corresponding instrument sleeve for placement within said guide channel, said instrument sleeve for guiding said medical instrument at said one or more preoperatively defined trajectories relative to a patient's anatomy. 
     
     
         11 . The guidance tool of  claim 10 , wherein said guide mechanism comprises a realignment sleeve for use in place of said instrument sleeve, said realignment sleeve providing a realignment of the instrument trajectory where the established trajectory requires adjustment. 
     
     
         12 . A preoperative process for designing at least one guidance tool for intraoperative use during bone or joint surgery wherein said at least one guidance tool is specific to the anatomy of the patient being treated, said process comprising
 creating a 3-D surface model of the patient's anatomy;   using the 3-D surface model of the patient's anatomy to preoperatively determine a trajectory of at least one medical instrument during bone or joint manipulation;   designing at least one guidance tool for registering against the patient's anatomy, said at least one guidance tool providing a guide mechanism and a mating surface, said guide mechanism for guiding said at least one medical instrument during said bone or joint manipulation at one or more preoperatively defined trajectory relative to a patient's anatomy, said mating surface providing positional registration of said at least one guidance tool on the patient's anatomy; and   preoperatively assessing the fit, size and design of the at least one guidance tool on the patient anatomy using the 3-D surface model of the patient's anatomy, and adjusting the design of the at least one guidance tool as necessary to achieve a correct fit.   
     
     
         13 . The preoperative process of  claim 12 , wherein said 3-D surface model of the patient's anatomy is created by one or more of CT, MRI, X-ray, and ultrasound. 
     
     
         14 . The preoperative process of  claim 12 , wherein said assessment of fit involves a quantitative figure of merit determination based on an examination of characteristic landmarks on said mating surface relative to said patient's anatomy. 
     
     
         15 . The preoperative process of  claim 12 , further comprising the identification of at least one characteristic anatomical landmark to be used in connection with a removable verification tool for mechanically verifying correct position of the at least one guidance tool on the patient's anatomy, said verification tool being configured for attachment to the at least one guidance tool. 
     
     
         16 . A method of facilitating bone or joint surgery using a preoperatively designed patient-specific guidance tool, said method comprising the steps of:
 placing the guidance tool directly upon the patient's anatomy for which it has been designed, said guidance tool providing a mating surface and a guide mechanism, said guide mechanism for guiding at least one medical instrument during bone or joint manipulation at one ore more preoperatively defined trajectory relative to a patient's anatomy, said mating surface providing positional registration of said guidance tool on said patient's anatomy;   assessing the position of the guidance tool upon the patient's anatomy;   assessing the preoperatively defined one or more trajectory governed by the guide mechanism of the guidance tool;   determining whether adjustments to the guide mechanism are necessary for achieving an optimal trajectory of said at least one medical instrument; and   adjusting, if necessary, the guide mechanism of said guidance tool to achieve one or more alternate trajectory for said at least one medical instrument.   
     
     
         17 . The method according to  claim 16 , wherein a verification tool, fitted to said guide mechanism of the guidance tool, is used to assess the position and orientation of the guidance tool having regard to the preoperatively defined trajectory. 
     
     
         18 . The guidance tool of  claim 17 , wherein said verification tool comprises at least one graduated section to determine misalignment of the guidance tool relative to said one or more preoperatively defined trajectories. 
     
     
         19 . The guidance tool of  claim 18 , wherein said verification tool comprises two graduated sections for providing misalignment values relative to the patient's anatomy, a first graduated section providing misalignment values in a longitudinal direction, and a second graduated section providing misalignment values in a radial direction. 
     
     
         20 . The method according to  claim 17 , wherein said guide mechanism comprises a guide channel and an instrument sleeve, and wherein a correction to realign said trajectory is provided by a realignment sleeve used in place of said instrument sleeve to achieve the corrected trajectory.