Abstract:
Featured is an apparatus that places or locates a proximal end portion of a penetrating member in a target area of a body. Such an apparatus or needle driver is particularly suited for locating a percutaneous needle in a soft tissue target area of a body particularly a body having inhomogeneous soft tissues. The apparatus includes a first arm that is configured and arranged so as to support a distal portion of the penetrating member and a first drive mechanism that is coupled to the first arm. The first drive mechanism is configured and arranged to move or translate the first arm from an initial position to any of a number of other positions that are spaced from the initial position and correspondingly translate the proximal end portion of the penetrating member. In another embodiment, the first arm also rotatably supports the penetrating member and the apparatus further includes a second drive mechanism coupled to the penetrating member distal portion and which is configured an arranged to rotate the penetrating member about the translational axis.

Description:
This application claims the benefit of U.S. Provisional Application Ser. No. 60/228,993 Aug. 30, 2000, the teachings of which are incorporated herein by reference. 

   STATEMENT OF GOVERNMENT INTEREST 
   Funding for the present invention was provided in part by the Government of the United States by virtue of Grant No. EEC9731478 by the National Science Foundation. Thus, the Government of the United States has certain rights in and to the invention claimed herein. 

   FIELD OF INVENTION 
   The present invention relates to methods, systems and devices for percutaneous surgery and more particularly to a controllable, motorized device for percutaneous needle placement in a soft tissue target including systems and methods related thereto. 
   BACKGROUND OF THE INVENTION 
   As an alternative to traditional surgical techniques or methodologies, percutaneous surgery has been found to significantly reduce morbidity and post-operative recovery time. A fundamental problem in clinical delivery of percutaneous therapy and needle biopsy is precise placement of the percutaneous needle in inhomogenous soft tissue. The accuracy of delivery is dependent upon both accurate targeting and on the precise driving of the needle on the target. In conventional systems and methods, the targeting accuracy exceeds and often greatly exceeds the driving accuracy that can be achieved. Furthermore, a wide spectrum of treatment methods require that the percutaneous needle be held firmly in the target location for a considerable period of time while the patient is in repiratory, cardiac and muscular motion. 
   This need for accurate delivery initially required that the surgeon performing the procedure have an extensive amount of experience and skill, however, there were shortcomings with such procedures. For example, then existing radiological image guidance techniques could not provide effective three-dimensional information to the surgeon regarding needle insertion. Consequently a number of robotic systems were proposed to assist in placement of the needle. Such robotic system solutions are found in “Intraoperative Imaging Guidance for Keyhole Surgery Methodology and Calibration,” Potamianos, P. Davies, B. L. and Hubbard, R. D., Proceedings for the First International Symposium on Medical Robotics and Computer Assisted Surgery, Pittsburgh, Pa., pp. 98-104 (1994); “Intraoperative Imaging Guidance for Keyhole Surgery Methodology and Calibration”, Potamianos, P. Davies, B. L. and Hubbard, R. D., Proceedings for the First International Symposium on Medical Robotics and Computer Assisted Surgery, Baltimore Md., pp. 156-164 (1995); “An Automated System for Precise Pecutaneous Access of the Renal Collection System”, Bzostek, A., Schreiner, S., Barnes, A. C., Cadeddu, J. A., Roberts, W. Anderson, J. H., Taylor, R. H. and Kavoussii, L. R. submitted for review to the Proceedings of the First Joint Conference of CVRMed and MRCAS, Grenoble France (1997) and PCT Publication No. WO 989/3688, published Aug. 27, 1998. A number of other robotics systems and methods for use in connection with surgical procedures, including sub-systems, methods and/or device related thereto, are found in U.S. Pat. Nos. 5,086,401; 5,299,288; 5,408,409; 5,279,309; 5,695,500; 5,630,431; 5,445,166; 5,402,801; 5,950,629; 5,976,156; 5,417,210; 5,572,999; 5,749,362; and 5,397,323. 
   Conventional needle drivers for percutaneous therapies typically utilize a friction transmission to achieve motion along the translational axis or idealized travel path, translational motion, to guide a needle into a soft tissue target. The translational axis is the axis along which the percutaneous needle generally travels to the soft tissue target. Such conventional friction transmission needle drivers, however, have a few shortcomings. 
   A frictional transmission has limited accurate encoding to track the translational position of the needle. For example, needle slippage results in loss of encoding, which in turn results in loss of accurate positioning of the needle in the translation axis. Needle slippage occurs when the force experienced by the needle is greater than the product of the preload contact force and the dynamic coefficient of friction. Needle deviation from the planned target also can occur because of needle deflection, organ deformation and respiratory, cardiac or muscular motion. Needle deflection can result from high needle insertion forces, the forces necessary for penetration into the tissue target, which is greatest at the initial point of entry. Needle deflection is a particular concern due to tissue inhomogeneities which in effect creates more of entry points for the needle as it traverses within the body. 
   It thus would be desirable to provide an improved new device, apparatus, system and related methods so a needle or other penetrating member can be accurately driven into an identified target in a soft tissue target and also retain encoding. It would be particularly desirable to provide such a device, apparatus, system and method that reduces or minimizes insertion forces in comparison to prior art devices and methods while the needle is being translated. It also would be desirable to provide such a device, apparatus, system and method that would lead to more accurate final positioning of the needle as compared to prior art devices. Further, it would be desirable to provide a device, apparatus, system and method providing more accurate encoding and tracking of translational needle position as compared to prior art device and methods. Such devices, apparatuses, systems preferably would be simple in construction and less costly than prior art devices and such methods would not significantly increase the complexity of surgical techniques to utilize the device, apparatus or system. 
   SUMMARY OF THE INVENTION 
   The present invention features an apparatus that places or locates a proximal end portion of a penetrating member in a target area of a body. Such an apparatus or needle driver is particularly suited for locating a percutaneous needle in a soft tissue target area of a body particularly a body having inhomogenous soft tissues. Also featured are systems that use such an apparatus as well as methods related to the apparatus and systems. 
   According to one aspect of the present invention, such an apparatus includes an arm, a first arm, that is configured and arranged so as to support the penetrating member, a distal portion of the penetrating member and a drive mechanism or drive transmission assembly, a first drive mechanism, that is coupled (i.e., mechanically coupled) to the first arm. The first drive mechanism is configured and arranged so as to move or translate the first arm from an initial position to any of a number of other positions that are spaced from the initial position and correspondingly translate the proximal end portion of the penetrating member. One of these other positions corresponds to locating the proximal end portion of the penetrating member in the target area. 
   In a further embodiment, the first arm also is configured and arranged to rotatably support the penetrating member and the apparatus further includes another drive mechanism or drive transmission assembly, a second drive mechanism, that is coupled to the penetrating member distal portion and which is configured an arranged so as to rotate the penetrating member about a long axis thereof, the translational axis. In a more particular embodiment, the second drive mechanism also is coupled to the first arm. 
   In another further embodiment, the apparatus further includes a controller that is configured and arranged so as to selectively control the first and second drive mechanisms. In more particular embodiments, the controller is configured and arranged to include a plurality or more of pre-established protocols to implement any one of a plurality or more of techniques for driving the proximal portion of the penetrating member from the initial position to the final position. In one specific embodiment, the surgical personnel manually make the change from one pre-established protocol to another pre-established protocol manually. In another specific embodiment the change from one pre-established protocol to another pre-established protocol is effected automatically by the controller according to a preprogrammed sequence or responsive to receipt of external signals. 
   Such techniques or protocols include both translating and rotating the penetrating member proximal portion when the proximal end of the penetrating member (e.g., needle) is proximal the barrier, membrane or the like defining the interface or outermost surface of the body to be penetrated (e.g., the point of entry). This includes the barrier or interface defining each layer of a body having an inhomogeneous structure. In the case of inhomogeneous tissue layers, the interface defining the boundary between the discrete tissue layers. Another exemplary technique is repetitively translating the penetrating member in a back and forth motion like a hammering motion. Such repetitive translating is done in conjunction with rotation of the penetrating member or without rotation of the penetrating member. The above-described protocols/techniques are illustrative/exemplary of a few protocols or techniques and thus should not be considered exhaustive of all the possible scenarios for operating the first and second drive mechanisms. 
   According to a second aspect of the present invention such an apparatus further includes another arm, a second arm, that is spaced from the first arm and wherein the first drive mechanism as it translates the first arm from the initial position also moves the first and second arms with respect to each other. More particularly, the first arm translates or moves towards the second arm. In further embodiments, the second arm includes a guide mechanism in which is received the penetrating member. The guide mechanism is configured and arranged so as to guide and maintain the penetrating member along the travel path (e.g., translational axis) desired for traversing the body from the entry point or location to the target area. 
   According to a third aspect of the present invention, the first arm is further configured and arranged to releasably support the penetrating member distal portion and the second arm guide portion releasably receives the penetrating member therein. In a more particular embodiment, each of the first and second members is further configured and arranged so as to include a releasable segment that is releasably secured to the other portion of the arm. In more particular embodiments, the apparatus further includes a release-grasp mechanism that is configured and arranged to secure the releasable segment to its arm and to de-secure the release segment upon some action by the surgical personnel. In a more specific embodiment, such de-securing occurs automatically when certain conditions (e.g., power failure) is determined to exist. 
   According to a fourth aspect of the present invention, the apparatus further includes the penetrating member, which penetrating member is configured an arranged so as to perform any of a number of techniques, protocols, surgical techniques or therapeutic techniques. These include but are not limited to injection of therapeutic agents in the target area, location an imaging device in the target area, biopsy, injection of a material in the target area to improve imaging of the target area and surround areas, and location of a device (e.g., RF or ultrasound transmitter) in the target area to perform a procedure, for example tissue ablation and breaking up stones. 
   According to a fifth aspect of the present invention, the apparatus further includes a sensing mechanism for sensing any one of a number of physical parameters (e.g., forces, vibrations) and for coupling the output of each of these sensors to the controller. In more particular embodiments, the controller is configured to give at least one of an auditory or visual que or message to the surgical personnel indicating that a certain condition might be present, for example a tissue wall or calcification, such that the personnel can determine if the driving protocol for the penetrating member should be adjusted (e.g., increase or decrease rotational speed) or changed (e.g., stop rotating and start a hammering translation motion). 
   Further, the controller is further configured and arranged so that it selectively controls the operation of the first and second drive mechanisms responsive to such signals. For example, the controller is configured and arranged to stop the drive mechanisms when a condition(s) suggestive or indicative of an anomalous condition is detected. Also the controller can be configured so as to provide an auditory and/or visual alarm of when the anomalous condition is detected. 
   According to a more particular aspect of the present invention, the apparatus is configured and arranged for encodable placement of a percutaneous needle in a soft tissue target, such as that of a human body. 
   Other aspects and embodiments of the invention are discussed below. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
     For a fuller understanding of the nature and desired objects of the present invention, reference is made to the following detailed description taken in conjunction with the accompanying drawing figures wherein like reference character denote corresponding parts throughout the several views and wherein: 
       FIG. 1  is a perspective view of a penetrating member driver according to the present invention on a member of a targeting apparatus/system; 
       FIG. 2  is a perspective view of the penetrating member driver of  FIG. 1  with sides of the housing removed for clarity; 
       FIG. 3  is a perspective view of the penetrating member driver of  FIG. 2  where the release-grasp mechanism is actuated to de-secure the release segment; 
       FIG. 4  is another perspective view of a portion of the penetrating driver of  FIG. 2  illustrating removal of the release segment from the arms; 
       FIG. 5  is a side view of an alternative penetrating member driver; 
       FIG. 6  is a block diagram of one scheme for controlling the driving of the penetrating member; and 
       FIG. 7  is an exemplary circuit for controlling the translational driving of the penetrating member with a force feedback to the joystick. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring now to the various figures of the drawing wherein like reference characters refer to like parts, there is shown in  FIGS. 1-5  various views of a penetrating member driver  100  according to the present invention particularly configured and arranged for driving a penetrating member, such as a needle  50 , into a target area of soft tissue of a body. These figures also illustrate various in process configurations of the penetrating member driver  100  as well as illustrating its use in connection with a member  60  of any of a number of manual, motorized or robotic targeting apparatuses or systems as is known to those skilled in the art. In use these manual, motorized or robotic targeting apparatuses or systems are operated so the needle  50  axis being held in the penetrating member driver  100  is positioned and oriented so that it points at the entry point of the body and also so that the needle is oriented such that it translates along the translational axis to the target area. Such apparatuses and systems are more particularly identified elsewhere herein, the teachings of which are incorporated herein by reference. 
   The needle  50  is any of a number of penetrating members known to those skilled in the art, and more particularly includes any of a number of percutaneous needles known to those skilled in the art. As more specifically described hereinafter each needle  50  also is configured so as to include a gear member  184  (see  FIGS. 2-3 ) that is attached to the exterior of the needle using any of a number of techniques known to those skilled in the art at a predetermined axial location. In use, a stylet also may be inserted into the lumen of the needle  50 , so as to provide axial support and so as to provide an end detail more appropriate for minimizing trauma at entry points and minimizing the forces required for penetrating the tissue boundary at the entry point, for example a diamond end detail. 
   The penetrating member driver  100  includes a housing  110 , first and second arms  120 ,  140 , a motorized translation transmission assembly  160 , a motorized rotation transmission assembly  180  and a latch assembly  190 . The housing  110  is configured and arranged so as to provide structural support to the first and second arms  120 ,  140 , the motorized translation transmission assembly  160  and the latch assembly  190 . In the illustrated embodiment, the housing also substantially encloses the motorized translation transmission assembly  160 , motorized rotation transmission assembly  180  and latch assembly  190 . The configuration, thickness, and materials of the housing  110  are selected such that it can provide the required structural support while minimizing its capability for being a source of contaminants to the medical procedure penetrating member driver  100  is being used in conjunction with. In an illustrative embodiment, the housing  110  is made from aluminum. 
   In the illustrated embodiment, the first arm  120 , where the translation arm, includes two parts, the support part  122  and the cantilevered part  124 , where the cantilevered part also includes a releasable segment  126 . The support part  122  is configured and arranged to receive and secure the cantilevered part  124  in a pocket  123  formed therein and to support the drive motor  182  for the motorized rotation transmission assembly  180 . The pocket  123  also provides a pathway for coupling the motorized rotation transmission drive motor  182  to the drive gear  186 . 
   The first arm support part  122  also is configured and arranged so as to include two through apertures therein arranged general perpendicular to the pocket  123 . One aperture is configured and arranged to receive therein the ball screw coupler  166  of the motorized translation transmission assembly  160  and to secure the ball screw coupler therein such that it cannot rotate. The other aperture is configured and arranged to receive and secure therein the guide member  178  of the motorized translation transmission assembly  160 . The inter-relationship between the first arm, these parts and the motorized translation transmission assembly in general is discussed below. 
   The configuration, thickness, and materials of the first arm support part  122  are selected such that it can provide the required structural support while minimizing its capability for being a source of contaminants to the medical procedure the penetrating member driver  100  is being used in conjunction with. The support part  122  also is configured and arranged so that any external moment loading, imposed on the first arm  120  is passed onto the linear guide  172  without distortion of the structure making up the support part. Because it is out of the field of view for the target area, the materials of the support part  122  need not be lucent to the particular type of source used for imaging, for example the materials need not be radiolucent (i.e., lucent to x-rays). In an illustrative embodiment, the first arm support part  122  is made from aluminum however other materials are contemplated for use. 
   The cantilevered part  124  extends outwardly from the support part  122  and the housing  110  and has a length such that the penetrating member  50  is located well away from the housing and support part so that the housing and support part are not located in the field of view for the target area or the point of entry. The cantilevered part  124  also is configured and arranged so that it has a pocket  132  therein that runs lengthwise. This cantilevered part  124  also is configured and arranged so that the gear drive  186  is rotatably disposed at a distal end of the pocket  132  and so that the drive belt  190  passes therethrough to mechanically couple the gearhead  168  and the drive gear. The gear drive  186  also is located or positioned such that the gear member  184  and the gear drive are in mechanical engagement with each other when the releasable segment  126  is secured to the first arm cantilevered part  124 . Additionally, the cantilevered part  124  is configured and arranged such that when the first arm  120  translates in a direction  102  towards or away from the second arm  140 , the needle  50  or penetrating member is correspondingly translated at the same time. 
   For purposes of releasably securing the needle  50  to the first arm  120 , the cantilevered part  124  includes a releasable segment  126 , which segment includes a catch arm  128  that extends outwardly from a portion of a surface. When the releasable segment is secured to the rest of the cantilevered part  124 , the catch arm  128  is located in a channel  134  that runs lengthwise within the cantilevered part  124  and continues through the support part  122 . When in this secured condition, a notch  130  or other surface artifact of the catch arm  128  is located proximal to and is put into engagement with a latch finger  192  of the latch assembly  190 . 
   The configuration, thickness, and materials for the first arm, cantilevered part  124  are selected such that it can provide the required structural support for the needle  50  and so that translational motion of the first arm  120  is correspondingly imparted to the needle. The cantilevered part  124  also is configured and arranged so that any external moment loading, imposed on the first arm  120  is passed onto the support part  122  and thence onto the linear guide  172  without distortion of the structure making up the first arm. Because the cantilevered part  124  is in the field of view for the target area, the materials of the cantilevered part are selected so as to be lucent to the particular type of source used for imaging, for example the materials are radiolucent (i.e., lucent to x-rays). In an illustrative embodiment, the first arm cantilevered part  124  is made from a plastic such an acrylic plastic however other radiolucent materials are contemplated for use. 
   In the illustrated embodiment, the second arm  140 , also the fixed arm includes two parts, the support part  142  and the cantilevered part  144 , where the cantilevered part also includes a release segment  146 . The second arm support part  142  is configured and arranged to receive and secure the cantilevered part  144  in a pocket  143  formed therein. The second arm support part  142  also is secured to the housing bottom  112  using any of a number of techniques known to those skilled in the art including welding, brazing, adhesively and mechanically (e.g., nuts, screws, bots, etc.). 
   The configuration, thickness, and materials for the second arm support part  142  are selected such that it can provide the required structural support while minimizing its capability for being a source of contaminants to the medical procedure the penetrating member driver  100  is being used in conjunction with. The second arm support part  142  also is configured and arranged so that any external moment loading, imposed on the second arm  120  is passed onto the housing  110 . Because it is out of the field of view for the target area, the materials of the support part  142  need not be lucent to the particular type of source used for imaging, for example the materials need not be radiolucent (i.e., lucent to x-rays). In an illustrative embodiment, the second arm support part  142  is made from aluminum however other materials are contemplated for use. 
   The cantilevered part  144  extends outwardly from the support part  142  and the housing  110  and has a length such that the penetrating member  50  is located well away from the housing and support part so that the housing and support part are not located in the field of view for the target area or the point of entry. The cantilevered part  144  also is configured and arranged so that it includes a guide  152  for the penetrating member/needle  50 . The guide  152  has a through aperture and is sized so it slidably receives the penetrating member/needle  50  therein. The guide  152  also is disposed and located at a distal end portion of the second arm  140  and located so that the penetrating member/needle  50  extends between the first arm  120  and the second arm  140  such that the penetrating member/needle  50  will translate along a predetermined axis, the translational axis, and so the gear member  184  is maintained in mechanical engagement with the drive gear  186 . 
   For purposes of releasably securing the needle  50  to the second arm  140 , the cantilevered part  144  includes a releasable segment  146 , which segment includes a catch arm  148  that extends outwardly from a portion of a surface. When the releasable segment is secured to the rest of the cantilevered part  144 , the catch arm  148  is located in a channel  134  that runs lengthwise within the cantilevered part  144  and continues through the support part  142 . When in this secured condition, a notch  150  or other surface artifact of the catch arm is located proximal to and is put into engagement with a latch finger  192  of the latch assembly  190 . 
   The configuration, thickness, and materials of the second arm, cantilevered part  144  are selected such that it can provide the required structural support for the anticipated mechanical loadings and intended service. The cantilevered part  144  also is configured and arranged so that any external moment loading, imposed on the second arm  140  is passed onto the support part  142  and thence onto the housing bottom  112  without distortion of the structure making up the second arm. Because the cantilevered part  144  is in the field of view for the target area, the materials of the cantilevered part are selected so as to be lucent to the particular type of source used for imaging, for example the materials are radiolucent (i.e., lucent to x-rays). In an illustrative embodiment, the cantilevered part  144  is made from a plastic such as an acrylic plastic however other radiolucent materials are contemplated for use. 
   The motorized translation transmission assembly  160  includes a motor  162 , a ball screw  164 , interconnecting gearing  163 , a ball screw coupler  166 , bearings  168 , and a linear guide  172 . The motor  162  is any of a number of types of fractional horsepower, bi-directional drive motors known in the art including electrical motors, pneumatically powered motors and hydraulically powered motors. In an exemplary illustrative embodiment, the motor is a bi-directional electrical motor. Preferably, the motor  162  is an encoded type. 
   The interconnecting gearing  163  that mechanically couples the motor  162  to the ball screw  164  is configured and arranged so that the motor rotates the ball screw with very little to, and including, no slippage therebetween. In an exemplary embodiment, the interconnecting gearing  163  includes a planetary gear reduction head, having a 4:1 reduction, so that a maximum translational speed can be developed. 
   The ball screw  164  also is mechanically interconnected to the ball screw coupler  166  secured in the first arm support part  122 . The ball screw coupler  166  is any of a number of devices known to those skilled in the art, which develop linear motion or motion in one direction generally parallel to the axis of rotation, responsive to rotational motion of a member rotating therein. Thus, when the ball screw  164  is rotated within the ball screw coupler  166  responsive to the operation of the motor  162 , the ball screw coupler in turn causes the first arm  120  to move in a direction  102  towards or away from the second arm  140  responsive to the rotation and the direction of rotation of the ball screw. The ends of the ball screw  164  also are supported by the bearings  168  to minimize the frictional losses in the rotation power translation. 
   This configuration and arrangement of the motorized translation transmission assembly  160  yields a translation drive that is essentially slipless in the bi-directional tranalational axis, which results in a drive capable of providing accurate and controllable encoding. The ball screw  164  also offers anti-backlash between the motor and the first arm, for accurate and controllable position encoding. In a particular embodiment, a low screw pitch diameter was selected for the ball screw  164  so that the motor  162  will experience relatively constant force feedback when the needle passes through different regions of anisotropic (i.e., inhomogeneous) soft tissue, and patient movements such as organ and respiration. Because there is no slippage and no loss of encoding, the penetrating member/needle  50  can be released from the penetrating member driving device  100  of the present invention without loss of encoding. Consequently, the penetrating member/needle  50  can be re-affixed to the penetrating member device  100  so that the end portion again lies within the same target area. 
   The linear guide  172  includes a rod member  174 , a track  176 , a sliding member  178 , a mount  173  for the rod member and a coupling mechanism  175 . The sliding member  178  is configured and arranged so a portion thereof slidably engages the track  176 . The sliding member  178  also is configured and arranged so another portion thereof is secured to the first arm  120 . The coupling mechanism  175  is secured to the sliding member  178  and overlays the rod member  174  such that the rod member is slidably received within the coupling mechanism and so that the rod member is slidably coupled with the sliding member. In this way, as the first arm  120  translates responsive to the rotation of the gear screw  164 , motion in directions other than direction  102  of translation by the first arm is suppressed by the sliding engagement between the sliding member  178  and the track  176  and by the sliding coupling of the sliding member and the rod member  176 . Similarly, external moment loadings being imposed on the first arm  120  are communicated to and suppressed by the linear guide  172 . The linear guide  172  also can further include one or more mechanical stops  177  to restrain the translational motion of the first arm  110 . 
   The motorized rotational transmission assembly  180  includes a motor  182 , the gear member  184 , a drive gear  186 , a gearhead  188  and a drive belt  189 . The motor  182  is any of a number of types of fractional horsepower, bi-directional drive motors known in the art including electrical motors, pneumatically powered motors and hydraulically powered motors. In an exemplary illustrative embodiment, the motor is a bi-directional electrical motor. This motor  182  need not be of the encoded type. 
   The gearhead  188  is coupled to the motor  182  and to the drive belt  189 . The drive belt  189  in turn is coupled to the drive gear  186  so that the operation of the motor causes the rotation of the drive gear. As indicated above, when assembled, the drive gear  186  is in mechanical engagement with the gear member  184  that is affixed to the penetrating member/needle  50 . Consequently the penetrating member/needle  50  rotates in a direction  104  in a clockwise or counterclockwise direction responsive to the direction of rotation of the motor  182 . 
   In a more particular embodiment, the gear member  184  for the penetrating member/needle  50  is preferably sized so that it can be adapted for use with penetrating members/needles having a wide range of different diameters or different gauges. More specifically, the inner hub of the gear member  184  has a diameter generally larger than the diameters of penetrating members/needles  50  for use in the present invention. In this way, the outer diameter of the gear member  184  does not change for different size needles and thus there is no change in the gear-contact dimension for the gear member  184 . Consequently, the same radiolucent first arm  120  and motarized rotation transmission assembly  180  is useable for penetrating members/needles  50  being of different diameters or gauges. In an illustrative embodiment, the space between the gear member inner hub is filled with a material such as epoxy so as to secure the gear member  184  to the penetrating member/needle  50  and to fill in any open space therebetween. 
   This drive gear  186  to gear member  184  arrangement yields a gear transmission for the penetrating member/needle  50  having little preload force and which provides bi-directional rotational motion and zero slippage and backlash. The drive gear  186 , the gear member  184  and the drive belt are constructed of a material appropriate for the intended structural loadings and also lucent to the imaging source as also discussed above for the first and second arm cantilevered parts  124 ,  144 . 
   In an exemplary embodiment, the gearhead  188  is a planetary gearhead which is compact in size and allows overall gear reduction to be achieved at the motor location. The drive belt  189  is any of a number of belts known to those skilled in the art and in an exemplary embodiment is an o-ring pulley belt. However, other types and configurations of drive belts, such as toothed drive belts are contemplated for use in the present invention otherwise consistent with the teachings of the present invention. 
   There is shown in  FIG. 5  and alternative arrangement for the rotation drive motor  182 . In this illustrative arrangement, the motor  182  is located so it extends below the first arm  120 . In the other illustrative embodiments the motor  182  is illustrated as extending above the first arm  120 . It should be recognized that this orientations of the motors  162 ,  182  for the motorized translation and rotation transmission assemblies  160 ,  180  are illustrative as the motors can be adapted so as to be arranged in other configurations otherwise consistent with the teachings of the present invention. 
   Each latching assembly  190  includes a latch finger  192 , a spring  194  or other biasing mechanism and a solenoid  196  that controls the actuation and de-actuation of the latch finger. As indicated above, when the penetrating member driver  100  is in its assembled configuration, the catch arm  128 , 148  of the first and second arm releasable segments  126 ,  146  are inserted into the channel  134  and the notch  130 ,  150  in each catch arm is put into engagement with the latch finger  192 . The latch fingers  192  are designed such that when the solenoid  196  is actuated, the latch fingers will engage and remain engaged with the notch  130 ,  150 . 
   When the solenoid is de-actuated the latch fingers  192  are released and biased so as to disengage from the notch  130 ,  150  thereby releasing each catch arm  128 ,  148 . Such de-activation can be the result of the actuation of a manual switch by the surgical personnel, responsive to a signal from a sensor, or responsive to the loss of power to the motors  162 ,  182  (e.g., loss of electricity, pneumatic pressure or hydraulic pressure). Thereafter, a spring  194  acts on each of the catch arms  128 ,  148  causing the catch arm to be moved outwardly and so that the corresponding releasable segment  126 ,  146  is biased away from the corresponding cantilvered part  124 ,  144  as is more particularly shown in  FIG. 3 . 
   Thereafter, either or both of the releasable segments  126 ,  146  can be completely detached from the corresponding cantilevered part  124 ,  144  as shown in  FIG. 4 . This also allows the surgical personnel to replace the penetrating member/needle with another sterilized penetrating member/needle of the same or different size and replace the guide member  152  for the second arm  120 , more particularly replace the guide member halves  154   a,b  in each of the releasable segment  146  and the cantilevered part  144  of the second arm. 
   Now referring to  FIG. 6  there is shown a schematic block diagram of a scheme or circuitry for controlling the operation of the motor  162  for the motorized translation transmission assembly  160 , the motor  182  for the motorized rotational transmission assembly  180 , and the solenoids  196  controlling the latch fingers  192  for each of the first and second arms  120 ,  140 . The circuitry includes a controller  200 , such as a microprocessor or digital signal processor as is known to those skilled in the art, configured and arranged so that various output signals are provided to any one of the motors  162 ,  182  or the solenoids responsive to certain input signals from sensors, switches or other input devices known to those skilled in the art. 
   Inputs are provided to the controller from one or more needle force sensor(s)  202 , or one more needle vibration sensor(s). For example, a number of force sensors  202  can be arranged to provide three dimensional needle force sensing which can provide feedback to determine if the needle trajectory coincides with any obstructions. Also such force and vibration sensing can be utilized as a mechanism for sensing the presence of an anomalous condition or a possible anomalous condition that requires either of the rotational or translation motors  182 ,  162  to be stopped so the medical/surgical personnel can re-evaluate what is going on to determine if the protocol or technique being used to drive the penetrating member should be altered, modified or terminated. For example, the sensors could be set so that translation would be stopped when the sensors output signals to the controller  200  are determined to be of the type and magnitude that could be or is representative of a condition that might be indicating the presence of calcification or hard tissue. 
   When such a condition is detected, the controller also could output signals to a display/warning device  206  which would generate appropriate auditory and/or visual ques to draw the surgical/medical personnel&#39;s attention to the condition. The medical/surgical personnel responsive to these ques and additional information could then establish or utilize another needle driving protocol to deal with the changed condition using an input device  208  such as a conventional keyboard, mouse and/or or joystick. After establishing another needle driving protocol, the needle driving process would be re-started using the new protocol. It should be recognized that it is within the scope of the present invention for the controller to be configured and arranged so as to include a number of different needle driving protocols that can be accessed and used by the medical/surgical personnel. 
   In an additional embodiment, the controller  200  is configured and arranged so as to include a depth of penetration value inputted by the medical personnel for a given procedure. Because the translational motion of the first arm  120  is encoded, the spatial movement of the first arm as it translates is evaluated by the controller  200  to determine if the needle has penetrated within the body to the depth of penetration. If yes, then the controller  200  outputs signals to the motors  162 ,  182  stopping the needle driving process as well as outputting signals to generate auditory/visual ques to draw the personnel&#39;s attention to this stoppage. 
   In another embodiment, motor/motor power sensors  212  are provided to sense the operability of the motor and/or the availability of sufficient power of the right frequency, voltage and current to run a given motor. If the sensors indicate that such power is not available or that one or motors has undergone a catastrophic failure, then the controller can be configured and arranged to automatically shutdown the needle driving process and/or give an auditory/visual warning to the medical personnel. For example, if the rotational motor  182  failed and the translation motor remained operation, the controller  200  would output a signal calling for the translational motor  162  to be shut down. 
   In yet another embodiment, a switch  210  is provided that allows the medical personnel to manually shutdown the needle driving process and/or trigger/de-actuate the solenoids  196  so as to release the penetrating member/needle from the first and second arms  120 ,  140 . For example, if the medical personnel saw the patient make a sudden movement or began coughing which could create a possibly unsafe condition if the needle  50  remained secured in the penetrating member driver  100 , the surgical/medical personnel can trip the solenoids  196  to release the needle using the switch  210 . Specifically, the switch  210  would output a signal to the controller  200  which in turn would trip the solenoids  196 . The solenoids  196  also are preferably configured so that when there is a loss of power to the solenoids, the solenoids automatically de-actuate thereby releasing the needle  50 . 
   There is shown in  FIG. 7  a block diagram of another control circuit for controlling translation of the needle  50 , which circuit also implements a force feedback to the joystick  208   a  that which is used to control or alter the ongoing needle driving process. In the illustrated embodiment, the controller  200   a  includes a digital signal processor  250 , and two signal amplifiers  252  for amplifying signals to the translational motor  162  that control the direction of rotation as well as being capable of controlling the speed of rotation. 
   The needle force/vibration sensor  220 , such as a pressure transducer, strain gauge or encoder, provides a signal output back to the DSP representative of the pressure/vibration being sensed. This output as described above is evaluated to determine if threshold values have been exceeded requiring termination of the needle driving process until the medical personnel can determine if this process can be restarted or continued, whether to change the needle driving protocol before restarting the needle driving process shutdown or whether to take some other appropriate action. Alternatively, the DSP could include instructions and criteria that allow the DSP to automatically alter or modify the needle driving protocol that was being implemented in accordance with some pre-established routine. 
   The needle force/vibration signals also are inputted back to the joystick as a force feedback from the DSP. As is known in the art, the joystick includes motors or mechanisms that can generate a back force on the joystick representative of a force. In the present invention, the force feedback from the DSP is representative of the force acting on the needle as it is being translated. 
   Although a preferred embodiment of the invention has been described using specific terms, such description is for illustrative purposes only, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the following claims.