Curved surgical instruments and method of mapping a curved path for stereotactic surgery

Abstract

The method of mapping a curved path for stereotactic surgery involves the selection of a helical-shaped path. The first step is toobtain an accurate image of the pertinent structures of the patient's internal areas. The image includes the lesion or target region ( 15 ) and potential opening site. Using the image, the non-target areas ( 16, 17, 19 ) surrounding the lesion area ( 15 ) are determined and evaluated for the medical acceptability of passing through them. A curved path (H) which is substantially helical in shape is then selected within the image such that the curved path (H) avoids these non-target areas ( 16, 17, 19 ), but intersects the target region ( 15 ) and the opening site. The corresponding surgical instrument ( 65 ) which will be used to follow the path has a rigid body (H) having a shape which is substantially identical to the path.

We claim:  
     
         1 . A method of mapping a curved path for stereotactic surgery using a substantially rigid surgical instrument to access an area of a patient's body comprising: 
 a) obtaining an accurate image of an area of the body, said image including an opening site and a target region;    b) determining high-risk areas around said target region;    c) selecting a non-linear curve within said image, wherein said curve is substantially helical in shape;    whereby said curve intersects said target region and said opening site, but not said high-risk areas, said curve defining the curved path for which a rigid stereotactic surgical instrument having an identical shape to said curve will be navigated to said target region.    
     
     
         2 . The method as recited in  claim 1  wherein the non-linear curve in said selection step is a helix.  
     
     
         3 . The method as recited in  claim 1  wherein said image obtaining step is performed using an imaging technique selected from the group consisting of: MRI, PET, CAT, plain radiography, SPECT, MEG, EEG, US, fMRI, angiography, colour doppler, and reference maps of the body.  
     
     
         4 . The method as recited in  claim 3  further comprising the steps of digitizing said image and interfacing said digitized image with a computer.  
     
     
         5 . The method as recited in  claim 1  wherein said determining step and selecting step are performed simultaneously.  
     
     
         6 . The method as recited in  claim 5  wherein a virtual reality apparatus is used to execute at least one of the steps.  
     
     
         7 . The method as recited in  claim 2  wherein said selecting step includes: 
 a) marking a target point P in said target region;  
 b) selecting straight line L as a helix axis; and  
 c) tracing a curve around said line L maintaining a constant radius r and angle α with respect to said line L, said curve intersecting said target point P.  
 
     
     
         8 . The method as recited in  claim 7  wherein said selecting step b) and said tracing step c) are performed substantially simultaneously.  
     
     
         9 . A method of mapping a curved path for stereotactic surgery using a substantially rigid instrument, said method being aided by a virtual reality apparatus, said apparatus including a 
 a display means, and a stylus adapted for allowing a user to interact with said virtual reality apparatus via said display means, said virtual reality apparatus adapted for displaying medical images on said display means and superimposing a helical curve of a selected radius r and angle α within said images, said method comprising: 
 a) displaying an accurate image of an affected area of a patient's body on said display means, said image including a target region;  
 b) determining high-risk areas around said target region;  
 c) pointing said stylus to a point P in said target region;  
 d) moving said stylus until a helical curve originating from point P is displayed on said displaying means such that no part of the helical curve intersects said high-risk areas, said curve defining the curved path for which a rigid stereotactic surgical instrument having an identical shape as said curve will be navigated to said target region.  
   
     
     
         10 . The method as recited in  claim 8  further comprising: 
 a) determining a location for an opening site;  
 b) determining whether said helical curve intersects the opening site; and  
 c) moving said stylus and selecting another helical curve until no part of the helical curve intersects said high-risk areas but intersects said opening site.  
 
     
     
         11 . A method of mapping a least-invasive curved path for stereotactic surgery using a substantially rigid instrument comprising: 
 obtaining an accurate image of an affected area of a patient's body, said image including a target region and an opening site;    determining high-risk areas around said target region;    assigning a medical acceptability value to each of said high-risk areas;    selecting a plurality of curves within said image wherein each of said curves is substantially helical in shape, and said curves intersecting said target region and said opening site;    assigning a medical acceptability value to each of said curves based on its interaction with said high-risk areas;    comparing said curves based on said medical acceptability value; and    choosing a curve with an optimal value, said curve defining the curved path for which a rigid stereotactic surgical instrument having an identical shape as said curve will be navigated to said target region.    
     
     
         12 . The method as recited in  claim 11  wherein each of said curves is helical in shape.  
     
     
         13 . A method of mapping a curved path for intracranial stereotactic surgery using a substantially rigid surgical instrument comprising: 
 obtaining art accurate image of an affected area of a patient's intracranial area, said image including a target region and an opening site;    determining high-risk areas around said target region;    selecting a curve within said image wherein said curve is substantially helical in shape,    whereby said curve intersects said target region and said opening site, but not said high-risk areas, said curve defining the curved path for which a rigid stereotactic surgical instrument having an identical shape as said curve will be navigated to said target region.    
     
     
         14 . The method of mapping a curved path for intracranial stereotactic surgery as recited in  claim 13  wherein said curve is helical in shape.  
     
     
         15 . A non-linear surgical instrument for stereotactic surgery conducted along a curved path comprising: 
 a substantially rigid, elongated body, said body being substantially helical in shape,    wherein said instrument is adapted for being inserted into a small opening on a patient's body and navigated precisely along a selected curved path having substantially same shape as said instrument to perform a surgical function.    
     
     
         16 . The surgical instrument as recited in  claim 15  wherein said rigid body is helical in shape.  
     
     
         17 . The surgical instrument as recited in  claim 15  further comprising 
 a monopolar electrode disposed at an end of said rigid body;  
 a conductor core electrically coupled to said electrode and disposed inside said rigid body;  
 wherein said rigid body is made of electrically insulating material;  
 whereby said instrument is adapted for measuring or delivering electrical signals.  
 
     
     
         18 . The surgical instrument as recited in  claim 15  further comprising 
 a plurality of electrodes of alternating polarity disposed at an end of said rigid body, said electrodes adapted for delivering electrical current to a localized area;  
 a protruding opening for collecting fluid samples disposed at said end;  
 a fluid channel disposed inside said rigid body leading to said opening; and  
 a power cable electrically coupled to said electrodes, said cable disposed inside said rigid body and around said fluid channel.  
 
     
     
         19 . The surgical instrument as recited in  claim 15  wherein said instrument is a biopsy sampling instrument further comprising 
 a flexible, withdrawable, and turnable shaft disposed inside said rigid body;  
 a collection chamber at an end of said shaft, said chamber adapted for receiving and storing a sample fluid;  
 and a rotatable window head at an end of said rigid body and over said collection chamber.  
 
     
     
         20 . The surgical instrument as recited in  claim 15  wherein said instrument is a needle adapted for extracting material or delivering medicine or other fluids, further comprising 
 a hollow core disposed along inside said rigid body;  
 a sharp point at a tip of said rigid body; and  
 a opening at said tip.  
 
     
     
         21 . The surgical instrument as recited in  claim 15  wherein said instrument is a resection instrument further comprising 
 a flexible, turnable shaft disposed along inside said rigid body;  
 a resection wire having a loop, said loop being cable of being in an active and retracted positions, said loop being outside said shaft in the active position, and inside said shaft in the retracted position.  
 
     
     
         22 . The surgical instrument as recited in  claim 15  wherein said instrument is a temporary implant placement instrument further comprising 
 a tip at an end of said rigid body, said tip having a material chamber adapted for releasing radiation or drugs through said tip.  
 
     
     
         23 . The surgical instrument as recited in  claim 15  wherein said instrument is a permanent implant placement instrument further comprising 
 a core slidably disposed inside said rigid body;  
 a detachable drug source or device disposed at an end of said rigid body, such that said drug source or device is detached by advancing said core.  
 
     
     
         24 . The surgical instrument as recited in  claim 15  wherein said instrument is a cooling or heating instrument for cooling or heating an isolated area of the patient's body further comprising 
 a tip disposed at an end of said rigid body;  
 a core inside said rigid body for delivering heat or cold; and  
 an insulating sheath surrounding said cable.  
 
     
     
         25 . The surgical instrument as recited in  claim 15  wherein said instrument is a drilling instrument further comprising 
 a rotatable flexible shaft inside said rigid body; and  
 a rotatable cutting burr attached to an end of said shaft.  
 
     
     
         26 . The surgical instrument as recited in  claim 15  further comprising 
 a hollow core disposed inside said rigid body adapted for guiding a flexible guide wire, said rigid body capable of being removed from the patient's body while leaving said guide wire in the curved path.  
 
     
     
         27 . The surgical instrument as recited in  claim 26  further comprising a channel inside said rigid body, said channel adapted for delivering electrical current or biological material in either direction.  
     
     
         28 . The surgical-instrument as recited in  claim 15  further comprising 
 a fixed hand grip disposed at an end of said rigid body;  
 a turning hand grip pivotally disposed adjacent to said fixed hand grip;  
 a tool disposed at an end opposite to said fixed and turning hand grip; and  
 a wire attached of said turning hand grip and said tool,  
 such that said tool can be opened or closed by rotating said turning hand grip around a pivot.  
 
     
     
         29 . The surgical instrument as recited in  claim 28  wherein said tool is a pair of scissors.  
     
     
         30 . The surgical instrument as recited in  claim 28  wherein said tool is a nibbler.  
     
     
         31 . The surgical instrument as recited in  claim 28  wherein said tool is a gripping apparatus.  
     
     
         32 . The surgical instrument as recited in  claim 28  wherein said tool is a spreading apparatus.  
     
     
         33 . The surgical instrument as recited in  claim 15  further comprising 
 a laser tip disposed at an end of said rigid body, said laser tip adapted for delivering localized radiation for burning away unwanted material, separating tissues, and cauterizing wounds.  
 
     
     
         34 . The surgical instrument as recited in  claim 15  wherein said instrument is a endoscope further comprising 
 a camera at an end of said rigid body;  
 a optical fiber connection for transmitting and receiving optical information disposed inside said rigid body and coupled to said camera; and  
 a means for lighting disposed at said end.  
 
     
     
         35 . The surgical instrument as recited in  claim 15  wherein said instrument is an ultrasonic aspirator further comprising 
 a vibrating source at an end of said rigid body adapted for delivering directed ultrasound for pulverizing tissues;  
 a liquid insertion tube disposed at said end for making a slurry of said tissues;  
 an extraction tube for extracting the slurry of tissues;  
 a fluid channel disposed inside said rigid body for delivering said slurry of tissues; and  
 a means for delivering power for said aspirator.  
 
     
     
         36 . The surgical instrument as recited in  claim 15  further comprising 
 a vibrating source at an end of said rigid body adapted for delivering low level ultrasound for creating detailed image;  
 a means for delivering power for said vibrating source.  
 
     
     
         37 . A guide block for a surgical instrument for stereotactic surgery, said instrument being substantially helical in shape, comprising 
 a rigid body,    a channel disposed in said rigid body, said channel having an identical shape as said surgical instrument, said channel adapted for fittingly receiving said surgical instrument and allowing said instrument to smoothly slide through said channel without deforming out of shape.    
     
     
         38 . The guide block as recited in  claim 37  wherein said rigid body is made of two parts which are mated together.  
     
     
         39 . The guide block as recited in  claim 38  wherein said parts are mated by being solidly mounted on a common rigid support.