Abstract:
A device for insertion of a flexible needle or other such instrument into a tissue, incorporating a collapsible support guide which supports that part of the needle which has not yet penetrated the tissue, preventing it from buckling, and an arrangement which pulls the needle from its proximal end to provide sufficient force for the penetration process. The collapsible support guide can be a pair of flexible strips connected along their length and enclosing the needle along its uninserted length in order to support it, with a mechanism at the distal end of the device to peel the strips from the needle as it is inserted. Insertion can be achieved by a pair of rollers engaging and advancing the strips distally. Alternatively, a telescopic support tube can be used to support the needle, the tube collapsing telescopically as the needle is inserted, to maintain clearance above the needle.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to the field of insertion of needles and other thin medical tools, and especially to devices for preventing the medical tool from buckling during insertion. 
       BACKGROUND 
       [0002]    Many routine treatments employed in modern clinical practice involve percutaneous insertion of needles, catheters and other thin medical tools, for biopsy, drug delivery and other diagnostic and therapeutic procedures. The aim of an insertion procedure is to place the tip of an appropriate medical instrument safely and accurately in a target region, which could be a tumor, lesion, organ or vessel. Examples of treatments requiring insertion of a needle, or another similar medical tool, include vaccinations, blood/fluid sampling, regional anesthesia, tissue biopsy, catheter insertion, cryogenic ablation, electrolytic ablation, brachytherapy, neurosurgery, deep brain stimulation and various minimally invasive surgeries. 
         [0003]    Such medical tools (e.g., needles) are generally thin walled, of small diameter and mostly very long. Due to these characteristics, and because of the force needed to penetrate the patient&#39;s skin (approx. 10N), it may be difficult to cause the needle to penetrate the patient&#39;s skin from the proximal end of the needle without the needle buckling under the force. The same problem may apply should the needle encounter a hard object in its travel, such as a bone. 
         [0004]    In co-pending PCT application number PCT/IL2014/050891, for “Needle Steering by Shaft Manipulation” having a common inventor with the present application, there is described a device for the insertion of a needle into a patient, in which the needle is held remotely from its proximal end and pulled via a friction based mechanism. Such a device may prevent buckling, but it is complex in construction, and does not easily enable the use of disposable sterilized needle packs. Furthermore, pulling the needle from its proximal end by means of a friction drive may not provide sufficient force to overcome the penetration forces described hereinabove. 
         [0005]    A friction drive generally requires applying radial forces on the needle, which could cause the needle to yield. As the trend in biopsy needles is for reduction of the needle wall thickness, this could become a significant issue. 
         [0006]    In U.S. Pat. No. 7,822,458 to R. J. Webster III et al, for “Distal Bevel Tip Needle Control Device and Algorithm”, there is described a method of percutaneously steering a surgical needle into a patient&#39;s tissue. One embodiment shows a pair of drive wheels pulling the needle into the patient&#39;s skin from its distal end, this embodiment having the same disadvantages as that of PCT/IL2014/050891. A second embodiment uses a telescopic guide, but has the disadvantage that because of the lead screw used in order to advance the needle, the height of the mechanism is maintained at its fixed full dimension, which hinders its use, for instance, within the limited bore of a CT system. 
         [0007]    There therefore exists a need for a new insertion device, which overcomes disadvantages of prior art devices. 
         [0008]    The disclosures of each of the publications mentioned in this section and in other sections of the specification, are hereby incorporated by reference, each in its entirety. 
       SUMMARY OF THE INVENTION 
       [0009]    The present disclosure describes methods and apparatus for the mechanical insertion of a flexible needle or any other thin long instrument or object, into soft medium (e.g., tissue) by use of a collapsible support guide which supports that part of the needle which has not yet penetrated the medium, preventing it from buckling, yet does not impede the continuous insertion process. Different implementations of the devices described in this disclosure include: 
         [0000]    (i) use of a flexible support guide, such as a pair of flexible strips connected along their length and enclosing the needle along at least a part of the needle&#39;s length. The strips are adapted to peel away from the needle as it is inserted, and this enables the needle to be inserted by advancing it from its proximal end in order to ensure that sufficient force can be applied for the penetration process;
 
(ii) use of a telescopic support tube which supports the needle and prevents that part of it outside of the patient&#39;s skin from buckling, and yet which collapses telescopically as the needle is inserted such that the height of the device does not impede use in limited spaces such as the bore of a CT system.
 
         [0010]    For the first implementation (i) described herewithin using a flexible support guide, a number of propulsion methods can be used in order to push or pull the needle-support guide assembly by its proximal end, into the patient&#39;s body, as follows: 
         [0000]    (a) The proximal end of the guide is pulled down via a pulling mechanism, such as by cables or straps;
 
(b) The guide itself is perforated and two or more rollers in the lower part of the assembly have protrusions that engage the perforations of the guide and pull the guide itself distally toward the patient&#39;s body.
 
(c) The guide is shaped like a rack with teeth throughout at least part of its length, and its teeth mesh with corresponding gear teeth positioned at the lower part of the assembly.
 
(d) A friction based mechanism, in which the guides have a coarse outer surface and a pair of oppositely facing pulleys are pressed against them. The pulleys themselves may also be coarse.
 
(e) An array of piezo-electric drivers are mounted on one or more sides of the needle or the guide, such that their drive elements make contact with the needle or the guide respectively, and their activation propels the needle or guide distally.
 
         [0011]    For the second implementation (ii) described herewithin, the preferred propulsion method is by use of a cable distally pulling the proximal end of the telescopic assembly with its encased needle. 
         [0012]    There is thus provided in accordance with an exemplary implementation of the devices described in this disclosure, a device for insertion of a tool, comprising: 
         [0000]    (i) a guide member having an opening adapted to allow passage of the tool therethrough,
 
(ii) a propulsion mechanism configured to advance the tool through the opening in the direction of an insertion site, and
 
(iii) a buckling prevention mechanism configured to support the tool along at least a portion of its length while it is advanced in the direction of the insertion site,
 
wherein the device is configured such that its height relative to the insertion site decreases as the tool is advanced in the direction of the insertion site.
 
         [0013]    Such a device may further comprise a head element to which the tool is coupled at its proximal region. In such a case, the propulsion mechanism may include the buckling prevention mechanism and comprise: 
         [0000]    (i) a pair of flexible strips connected along at least part of their length and having a central channel therebetween adapted to receive and support the tool, the pair of strips being coupled at its proximal region to the head element, and
 
(ii) a pair of rollers disposed on either side of the pair of flexible strips, and interacting therewith such that counter-rotation of the pair of rollers causes the pair of flexible strips to move between the pair of rollers,
 
wherein upon the tool being received within the central channel, the pair of flexible strips and the tool are connected by means of the head element, such that counter-rotation of the rollers in an appropriate direction pulls the pair of flexible strips and the tool towards the pair of rollers. Each roller of the pair of rollers may then comprise a plurality of protrusions arranged along its circumference, the plurality of protrusions being adapted to engage with a corresponding plurality of holes formed along the length of each strip of the pair of flexible strips. The pair of flexible strips may be connected on at least one side of the central channel adapted to receive the tool. Additionally, they may be not connected in a region of the central channel adapted to receive the tool. Such devices with rollers may further comprise a separating feature adapted to direct each strip of the pair of flexible strips around one of the pair of rollers. This separating feature may be simply the unconnected distal ends of the pair of flexible strips, each of the unconnected distal ends being wound around an associated roller of the pair of rollers. As an alternative, each roller of the pair of rollers may comprise a plurality of ridges arranged along its circumference, the ridges being adapted to engage with corresponding ridges formed in the pair of flexible strips.
 
         [0014]    In any of the above described devices, the central channel may include weakened sections along its length to facilitate the winding of each strip of the pair of flexibles strip around its associated roller. According to different implementations, the insertion device may comprise two separate units adapted to be connected to and disconnected from each other, each unit comprising: 
         [0000]    (i) one strip of the pair of strips,
 
(ii) one roller of the pair of rollers, and
 
(iii) at least a portion of the guide member.
 
         [0015]    In yet other implementations of the above described devices, the buckling prevention mechanism may comprise a telescopic tube. Such a telescopic tube implementation may further comprise a head element to which the tool is coupled at its proximal region, wherein the telescopic tube is attached between the head element and the guide member. In either of such cases, the device may further comprise at least one gripping member connected to the telescopic tube, the at least one gripping member being configured to receive the tool and to support it as it advances in the direction of the insertion site. The tool may be enclosed within the telescopic tube. Furthermore, the head element may be moved towards the guide member by means of a cable attached between the head element and the guide member. Such a cable may be wound around a pulley attached to the guide member. 
         [0016]    In such devices for insertion of a tool, the propulsion mechanism may comprise one or more piezo-electric actuators. 
         [0017]    In any of the above described devices, the opening may further comprise a constraining mechanism configured to be adjusted according to the dimensions of the tool, at least a portion of the constraining mechanism being disposed within the opening. Such a constraining mechanism may comprise at least two portions disposed opposite each other, and wherein at least one of the at least two portions is adapted to be moved towards another of the at least two portions. The constraining mechanism may then further comprise a tightening screw. 
         [0018]    Yet further implementations of the above described devices may further comprise an encoder configured to determine the position of the tool. Such an encoder may be an optical encoder configured to determine the position of the tool by one or more of sensing markings on the tool and sensing features on one or more components of the buckling prevention mechanism. 
         [0019]    Additional examples of the devices described above may comprise two separate units adapted to be connected to and disconnected from each other, each unit comprising: 
         [0000]    (i) at least a portion of the guide member,
 
(ii) at least a portion of the propulsion mechanism, and
 
(iii) at least a portion of the bucking prevention mechanism.
 
         [0020]    Furthermore, the tool may comprise one or more of: a needle, a cannula, a catheter, an introducer, a port, a fluid delivery tube or an electrode rod. 
         [0021]    There is further provided in accordance with an alternative implementation of the devices of the present disclosure, an assembly for insertion of a tool, comprising: 
         [0000]    (i) an insertion module comprising:
       (a) a guide member having an opening adapted to allow passage of the tool therethrough,   (b) a propulsion mechanism configured to advance the tool through the opening in the direction of an insertion site, and   (c) a buckling prevention mechanism configured to support the tool along at least a portion of its length during its advance in the direction of the insertion site,
 
(ii) a housing configured to receive the insertion module, and
 
(iii) an actuation mechanism configured to activate the propulsion mechanism.
       
 
         [0025]    In such an insertion assembly, the insertion module may be configured such that its height relative to the insertion site decreases as the tool advances in the direction of the insertion site. The insertion module may further comprise a head element to which the tool is coupled at its proximal region. Furthermore, the propulsion mechanism may include the buckling prevention mechanism and may comprise: 
         [0000]    (i) a pair of flexible strips connected along at least part of their length and having a central channel therebetween adapted to receive and support the tool, the pair of strips being coupled at its proximal region to the head element, and
 
(ii) a pair of rollers disposed on either side of the pair of flexible strips, and interacting therewith such that counter-rotation of the pair of rollers causes the pair of flexible strips to move between the pair of rollers,
 
wherein upon the tool being received within the central channel, the pair of flexible strips and the tool are connected by means of the head element, such that counter-rotation of the rollers in an appropriate direction pulls the pair of flexible strips and the tool towards the pair of rollers. In such circumstances, each roller of the pair of rollers may comprise a plurality of protrusions arranged along its circumference, the plurality of protrusions being adapted to engage with a corresponding plurality of holes formed along the length of each strip of the pair of flexible strips. Furthermore, the distal ends of the pair of flexible strips may be unconnected, each of the unconnected distal ends being wound around an associated roller of the pair of rollers.
 
         [0026]    According to different implementations, the insertion module may comprise two separate units adapted to be connected to and disconnected from each other, each unit comprising: 
         [0000]    (i) one strip of the pair of strips,
 
(ii) one roller of the pair of rollers, and
 
(iii) at least a portion of the guide member.
 
         [0027]    The buckling prevention mechanism in any of the alternative implementations of the devices of the present disclosure, may comprise a telescopic tube, in which case the buckling prevention mechanism may further comprise at least one gripping member connected to the telescopic tube, the gripping member being configured to receive the tool and to support it as it advances in the direction of the insertion site. In these alternative implementations too, the propulsion mechanism may comprise one or more piezo-electric actuators. Additionally, they may further comprise an encoder configured to determine the position of the tool. The tool itself may comprise one or more of: a needle, a cannula, a catheter, an introducer, a port, a fluid delivery tube or an electrode rod. Furthermore, a first portion of the actuation mechanism may be coupled to the housing, and a second portion of the actuation mechanism may be coupled to the guide member of the insertion module. In such devices, a locking mechanism may be configured to lock the insertion module within the housing. The locking mechanism may comprise: 
         [0000]    (i) a rotating member coupled to the insertion module, and
 
(ii) one or more slits formed in the housing,
 
wherein rotation of the rotating member such that at least a portion of the rotating member enters at least one of the one or more slits, locks the insertion module within the housing.
 
         [0028]    Furthermore, in the above described insertion assemblies, the housing may comprise one or more coupling elements adapted to couple the housing to an automated insertion device, the automated insertion device including at least a controller. Also, the insertion module may comprise two separate units adapted to be connected to and disconnected from each other, each unit comprising: 
         [0000]    (i) at least a portion of the guide member,
 
(ii) at least a portion of the propulsion mechanism, and
 
(iii) at least a portion of the bucking prevention mechanism.
 
         [0029]    According to yet further implementations of the devices of this disclosure, there is provided a device for insertion of a tool, comprising: 
         [0000]    (i) a pair of flexible strips connected along at least part of their length and having a central channel therebetween adapted to receive the tool, and
 
(ii) a pair of rollers disposed on either side of the pair of flexible strips, and interacting therewith such that counter-rotation of the pair of rollers causes the pair of flexible strips to move between the pair of rollers,
 
wherein upon the tool being received within the central channel, the pair of flexible strips and the tool are secured together at an end remote from the pair of rollers, such that counter-rotation of the rollers in an appropriate direction pulls the pair of flexible strips and the tool towards the pair of rollers.
 
         [0030]    In such yet further implementations, each roller of the pair of rollers may comprise a plurality of protrusions arranged along its circumference and adapted to engage with corresponding plurality of holes formed along the length of each strip of the pair of flexible strips. The pair of flexible strips may be connected on at least one side of the central channel adapted to receive the tool, and may be not connected in a region of the central channel. Such devices may further comprise a holder member configured to secure together the pair of flexible strips and the tool. They may also have a guide member, the guide member including: 
         [0000]    (i) one or more cavities adapted to accommodate the pair of rollers, and
 
(ii) an opening adapted to allow passage of the tool therethrough.
 
         [0031]    In that case, the opening may further comprise a constraining mechanism configured to be adjusted according to the dimensions of the tool, at least a portion of the constraining mechanism being disposed within the opening. The constraining mechanism may then comprise at least two portions disposed opposite each other, and wherein at least one of the at least two portions is adapted to be moved towards another of the at least two portions. 
         [0032]    Such yet further implementations may further comprise a separating feature adapted to direct each strip of the pair of flexible strips around one of the pair of rollers. Such a separating feature may comprise unconnected distal ends of the pair of flexible strips, each of the unconnected distal ends being wound around an associated roller of the pair of rollers. Alternatively, it may comprise a pair of structural edges, each being disposed sufficiently close to an associated roller that each flexible strip is directed by one of the edges around that roller disposed close to the edge. Alternatively, the pair of rollers may be disposed within a guide member, and each of the structural edges are then the edges of a component of the guide member. 
         [0033]    In any of such yet further implementations, the central channel may include weakened sections along its length to facilitate the winding of each flexible strip around its associated roller. Furthermore, the distance between two adjacent protrusions of the plurality of protrusions may be larger than the distance between two adjacent holes of the plurality of holes. The external surfaces of the pair of rollers and the external surfaces of the pair of flexible strips may alternatively be roughened such that the interaction between them is achieved by means of friction. The tool may comprise a tip, and the insertion device may further comprise a protecting element configured to prevent the tip from contacting an internal surface of the central channel as the tool is advanced in the direction of the insertion site. The protecting element may be inserted within the central channel, and it may comprise a hollow tube. Alternatively and additionally, it may be coupled to at least a portion of the insertion device externally to the central channel. Finally, in any of these yet further implementations, the insertion device may comprise two separate units adapted to be connected to and disconnected from each other, each unit comprising: 
         [0000]    (i) one strip of the pair of strips, and
 
(ii) one roller of the pair of rollers.
 
         [0034]    Additionally, alternative implementations of devices of the present disclosure may further involve an assembly for insertion of a tool, comprising: 
         [0000]    (i) an insertion module comprising:
       (a) a pair of flexible strips connected along at least part of their length and having a central channel therebetween adapted to receive the tool, and   (b) a pair of rollers disposed on either side of the pair of flexible strips, and interacting therewith such that counter-rotation of the pair of rollers causes the pair of flexible strips to move between the pair of rollers,   wherein upon the tool being received within the central channel, the pair of flexible strips and the tool are secured together at an end remote from the pair of rollers, such that counter-rotation of the rollers in an appropriate direction pulls the pair of flexible strips and the tool towards the pair of rollers,
 
(ii) a housing configured for receiving the insertion module, and
 
(iii) an actuation mechanism configured to rotate the pair of rollers.
       
 
         [0038]    In such an assembly, a first portion of the actuation mechanism may be coupled to the housing. Also, the insertion module may comprise a second portion of the actuation mechanism. Any of such assemblies may further comprise a locking mechanism configured to lock the insertion module within the housing. In such a case, the locking mechanism may comprise: 
         [0000]    (i) a rotating member coupled to the insertion module, and
 
(ii) one or more slits formed in the housing,
 
wherein rotation of the rotating member such that at least a portion of the rotating member enters at least one of the one or more slits locks the insertion module within the housing.
 
         [0039]    The above described assemblies may further comprise a separating feature adapted to direct each strip of the pair of flexible strips around one of the pair of rollers, and that separating feature may itself comprise unconnected distal ends of the pair of flexible strips, each of the unconnected distal ends being wound around an associated roller of the pair of rollers. Additionally, such assemblies may further comprise: 
         [0000]    (i) a front leading element coupled to the insertion module, and
 
(ii) a back leading element coupled to the housing,
 
wherein the front and back leading elements are configured to receive therebetween one of the unconnected ends of the pair of strips after the one of the unconnected ends is wound around its associated roller of the pair of rollers.
 
         [0040]    According to further implementations of such assemblies, the housing may comprise one or more coupling elements adapted to couple the housing to an automated insertion device, the automated insertion device including at least a controller. Furthermore, the insertion module may comprise two separate units adapted to be connected to and disconnected from each other, each unit comprising: 
         [0000]    (i) one strip of the pair of strips, and
 
(ii) one roller of the pair of rollers.
 
         [0041]    Finally, according to yet another implementation of the devices of the present disclosure, there is provided a device for insertion of a tool, comprising: 
         [0000]    (i) a head element to which the tool is attached at a proximal region of the tool,
 
(ii) an end guide element through which the tool is delivered to an insertion site, and
 
(iii) a telescopic tube attached between the head element and the end guide element,
 
wherein as the telescopic tube collapses, the head element is moved towards the end guide element and the tool advances towards the insertion site. In such devices, the head element may be moved towards the end guide element by means of a cable attached between the head element and the end guide element. That cable may be wound around a pulley attached to the end guide element. Any of these other implementations may further comprise at least one gripping element configured to receive the tool and to support it as it advances in the direction of the insertion site. The tool may be enclosed within the telescopic tube.
 
         [0042]    It is to be understood that the terms proximal and distal as used in this disclosure have their usual meaning in the clinical arts, namely that proximal refers to the end of a device or object closest to the person or machine inserting or using the device or object and remote from the patient, while distal refers to the end of a device or object closest to the patient and remote from the person or machine inserting or using the device or object. 
         [0043]    It is also to be understood that although the examples used throughout this disclosure relate to a device for insertion of a needle, the device is not meant to be limited to use with a needle but is understood to include insertion of any long thin tool, medical or other, which may undergo buckling if pushed or pulled from its proximal end without any support means, including a needle, port, introducer, catheter (e.g., ablation catheter), cannula, surgical tool, fluid delivery tool, or any other such insertable tool. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0044]    The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which: 
           [0045]      FIG. 1  shows schematically a cross-sectional view of a first exemplary implementation of an insertion device of the present disclosure. 
           [0046]      FIG. 2  shows an axial cross-section view of a needle enclosed between the two guiding strips of the insertion device of  FIG. 1 . 
           [0047]      FIG. 3  is an isometric view showing schematically an implementation of a flexible strip device with perforations running along the length of the strips. 
           [0048]      FIG. 4  is an isometric view showing schematically an implementation of a flexible strip device with ridges running along the length of the strips. 
           [0049]      FIGS. 5A and 5B  illustrate schematically an implementation in which the motion is applied to the needle by means of piezoelectric motors; in  FIG. 5A  the motors operate on the flexible strips, and in  FIG. 5B  directly on the needle. 
           [0050]      FIG. 6A  illustrates schematically a further implementation of the insertion devices of the present disclosure, in which the needle is supported from buckling by means of a telescopic tube having gripping clamps in each of its levels. 
           [0051]      FIG. 6B  is a close up view of the needle clamps of the device of  FIG. 6A . 
           [0052]      FIG. 7  shows an alternative example of a telescopic tube support device, showing a wire traction assembly for the needle head. 
           [0053]      FIG. 8A  shows a perspective view of an exemplary implementation of the flexible strip device with perforations running along the length of the strips of  FIG. 3 . 
           [0054]      FIG. 8B  shows an exemplary needle constraining mechanism. 
           [0055]      FIG. 9  shows another perspective view of the insertion device of  FIG. 8A . 
           [0056]      FIGS. 10A-10B  are top views of two exemplary arrangements of the rollers and the strips of the insertion device of  FIG. 8A . 
           [0057]      FIG. 11  is a cross-sectional view of operative interface between the rollers and the strips of the insertion device of  FIG. 8A . 
           [0058]      FIGS. 12A-12C  are longitudinal cross-sectional views depicting three needle insertion stages using the needle insertion device of  FIG. 8A . 
           [0059]      FIG. 13  shows a perspective view of an exemplary insertion assembly comprising the insertion device of  FIG. 8A  coupled to a robotic end effector. 
           [0060]      FIG. 14  is an exploded view of the insertion assembly of  FIG. 13 . 
           [0061]      FIGS. 15A-15B  are perspective views of an exemplary mechanism for securing the insertion device to the robotic end effector; in  FIG. 15A  the locking mechanism is in an open state; in  FIG. 15B  the locking mechanism is in a closed state. 
           [0062]      FIG. 16  shows exemplary rear and front guides for controlling the strips&#39; advancement direction. 
           [0063]      FIGS. 17A-17B  show perspective and longitudinal cross-sectional views, respectively, of an exemplary strip having weakened sections along the length of its longitudinal groove. 
           [0064]      FIGS. 18A-18B  show isometric views of an exemplary modular insertion device in assembled ( FIG. 18A ) and disassembled ( FIG. 18B ) states. 
       
    
    
     DETAILED DESCRIPTION 
       [0065]    Reference is first made to  FIG. 1 , which shows schematically a cross-sectional view of a first exemplary implementation of the needle insertion devices described in this disclosure.  FIG. 1  shows an insertion device  10 , with a needle (or any other thin insertable element)  100  held between a pair of flexible strips  110 , of supporting medium. The strips are held together conveniently by means of an adhesive, welding, geometric lock mechanisms such as a snap fit mechanism, or any other suitable attachment means, and the needle  100  is held between the two strips  110  down a thin channel running down the center of the coupled strips  110 . The distal end of the insertion device  10  comprises a holder  150  in which a pair of rollers  120  are disposed. The holder  150  further includes an opening  152  for guiding the needle  100  distally towards the patient&#39;s body. The rollers  120  are positioned within the holder  150  such that they contact the strips  110 , and as the rollers  120  counter-rotate, the double strip-needle assembly moves between the rollers  120 . The rollers  120  may be positioned within cavities formed within the holder  150 , the inner walls of the cavities being a close fit to the outer surfaces of the rollers  120 , such that as the flexible strip-needle assembly passes between the rollers  120 , the needle  100  is able to proceed through the opening  152  beyond the rollers  120 , while each one of the flexible strips  110  is peeled away from the needle  100  on either side of the rollers  120 . The needle then emerges from the double roller assembly bereft of its flexible strip covering, and ready for insertion into the patient&#39;s body. In some implementations, a “knife-edge” (not shown in  FIG. 1 ) or the straight corner of one of the holder elements may be positioned such that it causes the peeling of the flexible strips  110  away from the needle  100  and around the rollers. In order to assist in this action, the forward (i.e., distal) ends of the twin flexible strips  110  may be left unconnected so that each can peel away freely around its own roller  120 . The insertion device  10  may even be supplied with each unconnected strip end partially wound around its roller  120 , or even attached thereto, or just directed each towards a distal point on the circumference of its roller  120 , such that rotation of the rollers  120  causes the strips  110  to peel away from the needle  100  without the need for an “knife-edge” or the like to separate the strips  110  from each other and from the needle  100 . 
         [0066]    The strips  110  may be paper-based or plastic-based, or made of any other material capable of supporting the needle  100  along its length, thereby preventing it from buckling, but at the same time being flexible enough to curve around the rollers  120  and away from the needle  100 . Such materials may be, for example, Polyethylene terephthalate (PET), Polyurethane (PU) or rubberized fabric. At their proximal ends, the flexible strips  110  may be attached to the needle head  102 , or to a needle head holder  160 , which encloses and grips the needle head  102 , such that as the rollers  120  counter-rotate and move the double strip-needle assembly towards the patient&#39;s skin, the proximal end of the flexible strips  110  pulls with it the needle head  102 , and thus the needle  100 , distally towards the insertion point in the patient&#39;s skin. The propulsion of the needle  100  from its proximal end is a unique feature which provides the needle  100  with sufficient force to enable it to overcome any obstacles in its insertion path, whether at the skin entry point or further down during the insertion process. 
         [0067]    An encoder may optionally be disposed adjacent to the strips  110 , so that the position of the strips, and hence the insertion position of the needle  100  can be determined, such as by a controller or a processor (not shown) receiving the output signals of the encoder. By this means, the medical personnel are able to track the progress of the insertion depth of the needle  100 . The encoder can be, for example, an optical encoder, which can either count features on the strip  110 , such as the strip drive holes or ridges, as will be shown hereinbelow in  FIGS. 3 and 4 , or can detect markings on the needle itself. 
         [0068]    The insertion device  10  may be a stand-alone device, or it may be part of an insertion assembly/system. In case the insertion device  10  is a stand-alone device, it may further comprise an actuation mechanism, e.g., motor and gears, for rotating the rollers  120  and thus moving the needle  100  towards (and into) the patient&#39;s body. In the case that the insertion device is part of an insertion assembly/system, it may be configured to be coupled to an external actuation mechanism. 
         [0069]    Reference is now made to  FIG. 2 , which is an axial cross-section view of the two strips  110  of the insertion device of  FIG. 1  and the needle  100  enclosed therebetween. As shown, the two flexible strips  110  are coupled together along their width, except in the region where they envelop the needle  100  at their center line. Each strip  110  has a groove  114  running along its centerline, providing the strip with an “omega-like” traverse cross-section, such that when the strips  110  are coupled together, e.g., using an adhesive, the longitudinal grooves  114  of the two strips  110  form together a hollow tube, or a channel, which receives and encloses the needle  100 . The strips  110  may be coupled to the needle head  102  (not shown in  FIG. 2 , but visible in  FIG. 1 ) or secured to the needle holder  160  (not shown in  FIG. 2 ) together with the needle head  102 . 
         [0070]    As mentioned above, a number of methods are available in order to propel the needle distally into the patient&#39;s body. Reference is now made to  FIG. 3 , which is an isometric view showing schematically a first implementation of the flexible tape device  30 . In this implementation the flexible strips  310  have perforations  312  running along at least a portion of the length of the strips  310  and on either side of the needle position along the centerline. As these perforations  312  engage with corresponding protrusions (or -teeth)  322  on the rollers  320 , and as the rollers  320  counter-rotate in the appropriate direction, the double strip-needle assembly is forced in a distal direction. The proximal ends of the strips  310  are attached to the needle head  302  and/or to the needle head holder  360 , such that as the strips  310  move distally towards the patient&#39;s body, their proximal ends pull the needle towards the patient. More specifically, counter-rotation of the rollers  320  pulls downwardly the coupled strips  310  via a “timing belt-like” mechanism comprised of the rollers&#39; protrusions and the strips&#39; holes. The strips&#39; pull forces then react with the needle head holder  360  which pushes the needle  300  downwardly from the needle head  302 . This force can be substantially higher than that which could be obtained if the rollers  320  were to grip the needle  300  itself by frictional forces, and pull it down from its distal end. As mentioned above, the entire device  30  can be a stand-alone device or it can be part of an insertion system, e.g., it can be mechanically (e.g., robotically) held to align the needle  300  relative to the patient. 
         [0071]    Reference is now made to  FIG. 4 , which illustrates schematically an alternative method of locomotion for the flexible strips. In this implementation the rollers  420  are configured as gears, and the strips  410  are formed with ridges  415  on their outer edges and across at least a part of their width. The ridges  415  mesh with the teeth  425  of the rollers/gears  420 , similarly to a rack and pinion mechanism, and as the rollers/gears  420  counter-rotate, the double strip-needle assembly is forced in a distal direction. The attachment method of the flexible strips  410  at their proximal ends may be the same as that described for the implementation of  FIG. 3 . 
         [0072]    Although the implementations shown in  FIGS. 3 and 4  provide the double strip-needle assembly with optimum, slip-free propulsion force, it is also possible to use conventional friction forces to propel the assembly. In such an embodiment the surfaces of the rollers and the external surfaces of the flexible strips have a friction interface, such as roughened surfaces on one or on both, so that rotation of the rollers causes the flexible strips to move accordingly. 
         [0073]    In order to provide sterilized operation of the device, a number of options are available. The flexible strips may be supplied with the needle installed as a complete sterile assembly, ready for mounting into the roller assembly. Alternatively, the roller assembly may also be part of the supplied device, making the entire device a disposable one-time use device. In further embodiments, the roller assembly, with the strips inserted thereto devoid of any needle, may be provided as a one-time use disposable unit, such that the user can choose the needle to be installed into the double flexible strip guide. In such embodiments, the double flexible strip guide may be supplied with a thin walled introducer tube down its bore, into which the user can insert the needle, following which the introducer tube can be withdrawn and the needle left enveloped by the flexible strips guide. This enables the user to introduce the needle without unintentionally scratching or puncturing the soft material of the flexible strips, which may further result in particles of the strips&#39; material remaining inside the needle and entering the patient&#39;s body. 
         [0074]    Another solution for preventing the needle from scratching the inner surface of the strips may be, for example, including within the bore between the strips a short rod (i.e., shorter than the length of the bore between the strips) with a cone-shaped head, positioned at the top (proximal) end of the bore, the concave side of the cone-shaped head facing the proximal end of the bore, and thus also the incoming needle, such that when the needle is introduced into the bore, its tip encounters the bottom of the concave side of the cone-shaped rod head, and as the needle is being inserted into the bore it pushes down on the cone-shape rod head, thus pushing the entire rod downwardly until the rod falls out from the bottom (distal) end of the bore and the needle is left therein. Yet a further solution may be using an external stabilizing mechanism that is coupled to the device, or at least to the double strip-needle assembly, in order to hold it straight and prevent the strips from folding as the needle is being inserted into the bore, thus preventing the needle from scratching/puncturing the strips&#39; inner surface. Once the needle is positioned properly within the bore between the strips, the external stabilizing member may be removed. Such a mechanism may be disposable and provided with the device, i.e., pre-assembled, and discarded after a single use. 
         [0075]    Reference is now made to  FIGS. 5A and 5B , which illustrate schematically an implementation in which the motion is applied to the needle by means of piezoelectric motors. In  FIG. 5A , the piezoelectric motors  530  are situated on either side of the flexible strips  510 , such that as they are activated, their driver legs  535  move the strips  510  with the encased needle  500  distally towards the patient&#39;s body. In this implementation, the rollers  520  need not take part in the propulsion, and can function just in order to guide the flexible strips  510  so that they are peeled away from the needle  500 .  FIG. 5B  shows a similar implementation except that no flexible strip is used, and the piezoelectric motors  530  operate directly on the needle  500 . 
         [0076]    Reference is now made to  FIGS. 6A to 7 , which illustrate schematically further implementations of the insertion device of the present disclosure, in which the needle is supported from buckling by means of a telescopic tube which provides support along the length of the needle. However unlike prior art telescopic support systems, these implementations enable the height of the device to be reduced as the needle is inserted, such that they are more convenient for use in limited space situations, such as in the bore of a CT system. The needle is attached to a holder element at its proximal end, and to a needle guide at its distal end to align the correct insertion point of the needle. The telescopic tube assembly is attached between the holder element and the end guide to provide support to the needle as it is pushed (or pulled) into the patient by means of a force applied to the holder element. 
         [0077]      FIG. 6A  shows an insertion device  60  having a telescopic tube  610  attached to the needle  600  by means of clamps  620 , which allow the needle to slide through them. As the holder element  660 , to which the needle is attached, is pushed (or pulled) distally to insert the needle  600  into the patient&#39;s body, the telescopic tube  610 , which is connected between the holder element  660  and the distal end guide  640  of the device, collapses, enabling the holder  660  to approach the distal end guide  640  as the needle  600  is inserted. The holder element  660  may be pushed down manually or it may be pushed or pulled down using various propulsion mechanisms, such as a pulley wheel and a cable, as shown below in  FIG. 7 . In some implementations, the needle  600  is not externally attached to the telescopic tube  610 , but encapsulated therein. 
         [0078]    Reference is now made to  FIG. 6B , which is a close up view of the clamps  620  of the device shown in  FIG. 6A , showing how the needle  600  can slide through the openings in the clamps  620  as the telescopic tube  610  collapses upon itself, as shown in region  650  of the telescopic tube assembly. 
         [0079]    Reference is now made to  FIG. 7 , which shows a further exemplary implementation of the telescopic tube support devices shown in  FIGS. 6A and 6B , showing an insertion device  70  in which the motion of the needle  700  is achieved by means of a cable  720  attached to the needle head holder  760 , and passed around a pulley wheel  730  at the distal end of the telescopic tube  710 , and pulled manually or by means of a motor, a hydraulic/pneumatic piston or any other suitable actuation/propulsion mechanism(not shown). By means of such a configuration, needle motion can be obtained by means of a mechanism whose length collapses together with the telescopic support guide  60 , thereby overcoming the above mentioned problem of how to perform needle insertion in limited spaces, where the length of a conventional lead screw drive mechanism connected between the needle head and the distal end, for example, as described in the abovementioned U.S. Pat. No. 7,822,458, would interfere with this aim. 
         [0080]    Reference is now made to  FIGS. 8A-11C , which show an exemplary implementation of the insertion device shown in  FIG. 3 , i.e., a flexible strip device with perforations running along the length of the strips. In this implementation, the insertion device (which may also be referred to as “insertion module”) is configured as part of an insertion assembly, which is configured for coupling to an automated insertion system (e.g., a robotic system). Such an automated insertion system may be body-mounted or may be configured for coupling to a dedicated arm connected to the patient&#39;s bed or to the imaging device (e.g., CT, MRI), if the procedure is image-guided. 
         [0081]      FIG. 8A  shows a perspective view of an insertion module  80  comprising a needle (or any other insertable tool, such as an introducer, a catheter, etc.)  800  enclosed within a channel formed by two flexible strips  810   a ,  810   b  coupled together. In some implementations, the needle  800  is provided together with the insertion module  80 , i.e., as an integral component of the insertion module, whereas in other implementations, the insertion module is configured to receive a variety of different commercially available needle types, and the needle is chosen and introduced into the insertion module by the user (e.g., nurse, physician) prior to initiating the insertion procedure. 
         [0082]    The flexible strips  810   a ,  810   b  have perforations (or -holes)  812  running along at least a portion of their length, and a groove  814   a ,  814   b  running along their longitudinal centerline, such that when the strips are attached to each other their coupled grooves  814   a ,  814   b  form together the channel that receives and encloses the needle  800 . 
         [0083]    In some implementations, each strip  810   a ,  810   b  may include four rows of perforations  812 , e.g., two rows on each side of the groove  814   a ,  814   b , as shown in  FIG. 8A . In other implementations, each strip  810   a ,  810   b  may include two rows of perforations  812 , one row on each side of the groove  814   a ,  814   b , as shown below in  FIG. 9B . It can be appreciated that the arrangement of the perforations is not limited to two or four rows, and the strips may include any number of perforation rows or any other applicable perforation arrangement. 
         [0084]    The insertion module  80  further comprises two rollers  820   a ,  820   b  having protrusions  822  thereon. The protrusions  822  are aligned with the perforations  812  of the strips  810   a ,  810   b , such that as each roller  820   a ,  820   b  rotates, its protrusions  822  engage the perforations  812  of the corresponding strip  810   a ,  810   b , resulting in the strips  810   a ,  810   b  being pulled down and around the rollers  820   a ,  820   b.    
         [0085]    The insertion module  80  may further include a bevel gear  830  mounted on the same shaft  840   a  as one of the rollers, in this case roller  820   a , such that rotation of the bevel gear  830  causes roller  820   a  to rotate in the same direction. Counter-rotation of the second roller  820   b  is achieved via two gears mounted at the opposite end of the shafts  840   a ,  840   b , as described below in  FIG. 8B . 
         [0086]    The shafts  840   a ,  840   b , and the rollers  820   a ,  820   b  may be enclosed within a holder  850 , which may include a shaft (or -axes) holder portion  853 , a strip guide portion  855  and a needle guide portion  857 . The shaft holder portion  853  is configured to hold and secure the position of the shafts  840   a ,  840   b . The strip guide portion  855  is configured to lead the strips away from the rollers as the rollers continue to rotate, and its walls may include slits  8552  that allow passage for the protrusions  822  as the rollers rotate. The needle guide portion  857  may include an elongated “tube-like” opening (not shown in  FIG. 8A ), which is configured to receive the needle  800  as it is pulled (or pushed) in the distal direction and the strips  810  are peeled away from the needle  800 . The needle guide portion  857  also confines the needle  800  to the elongated opening and thus guides the needle  800  in the desired direction of insertion. 
         [0087]    In some implementations, in order for the insertion module  80  to be used with a variety of needle types and sizes, the elongated opening may have a diameter that is equal or slightly larger than that of the needle with the largest diameter (gauge) intended for use with the insertion module  80 . In other implementations, the elongated opening may include therewithin a constraining mechanism, which can be adjusted according to the diameter of the needle being used. An exemplary constraining mechanism is shown in  FIG. 8B , which is a transverse cross-sectional view of the mechanism. The constraining mechanism may include a stationary portion  8572 , which is fixedly connected to the inner surface  8573  of the needle guide portion  857  of the holder  850 , and a moveable portion  8574 . The moveable portion  8574  may be connected to a screw (or -bolt)  8576  whose head is positioned outside the needle guide portion  857  so that it is accessible to the user. The bolt  8578  may be coupled to a stationary nut  8578 , such that rotation of the bolt  8576  results in linear movement of the moveable portion  8574 . In some implementations, the stationary and moveable portions may each comprise a block with two triangular edges  8571 ,  8575  respectively, forming therebetween a v-groove  8573 ,  8577  respectively, and as the moveable portion  8574  advances towards the stationary portion  8572  the triangular edges  8575  of the moveable portion  8574  fit beneath the block of the stationary portion  8572 , as shown in  FIG. 8B , or vice versa. In other implementations, the stationary and moveable portions may each comprise a plurality of such blocks and the triangular edges  8571 ,  8575  intertwine as the moveable portion  8574  advances towards the stationary portion  8572 . Thus, after a needle  800  is inserted into the insertion module, the user rotates the bolt  8576  in the appropriate direction such that the moveable portion  8574  advances towards the stationary portion  8572  until there is contact between the needle  800  and the two v-grooves  8573 ,  8577  and the needle  800  is tangent to each of the triangular edges  8571 ,  8575  along a single line  8579  (shown as a dot in  FIG. 8B ). It can be appreciated that the constraining mechanism may include instead of the bolt  8576 , or in addition to the bolt, a spring (not shown), or any other element suitable for moving/pushing the moveable portion  8574  towards the stationary portion  8572 . 
         [0088]    The axes holder portion  853 , strip guide portion  855  and needle guide portion  857  may be three separate components assembled together to form the holder  850 , or they may be manufactured as a single unit. In some implementations two of the three portions (e.g., the strip guide and needle guide portions) may be manufactured as one component, which is then coupled to the third portion (e.g., the axes holder portion). 
         [0089]    The insertion module  80  may further include a needle head holder  860 , which secures together the needle head  802  and the proximal end of the strips  810   a ,  810   b . In some implementations, the needle head holder  860  may be composed of two portions  862  which are coupled together after the needle  800  is inserted into the channel between the two strips  810   a ,  810   b , e.g., using screws, an adhesive or a latch mechanism. In some implementations, the two portions  862  of the needle head holder  860  may be fixedly secured together at their distal end, to which the proximal ends of the strips  810   a ,  810   b  are attached, and after the needle  800  is inserted into the channel between the two strips, the proximal (top) ends of the two portions  862  are joined together over the needle head  802 . If intended for use in the medical field, the insertion module  80  should be a disposable single-use device, in order to prevent cross-contamination between patients. Thus, in some implementations, in order to ensure that the insertion module  80  is not reused with a new needle, the needle head holder  860  may be configured such that once it is fastened over the needle head  802 , it cannot be removed from the needle head  802 , or that removing the needle head holder  860  from the needle head  802  causes permanent damage to the needle head holder  860  such that it loses its functionality. 
         [0090]      FIG. 9  shows another perspective view of the insertion module  80 . As described above, the insertion module  80  may include a bevel gear (not shown in  FIG. 9 ), which in this implementation is mounted on shaft  840   a  of roller  820   a . Thus, rotation of the bevel gear  830  causes roller  820   a  to rotate in the same direction. The insertion module  80  further includes two gears  870   a ,  870   b  which are mounted on the roller shafts  840   a ,  840   b  respectively. The gear  870   a  is mounted on shaft  840   a  at the end opposite the end at which the bevel gear is mounted, such that rotation of the bevel gear causes rotation of the gear  870   a  in the same direction as the bevel gear and roller  820   a . The teeth of the gear  870   a  mesh with the teeth of the gear  870   b , causing the gear  870   b  to rotate in the direction opposite that of the gear  870   a . Since the roller  820   b  is mounted on the same shaft  840   b  as the gear  870   b , rotation of the gear  870   b  results in rotation of the roller  820   b  in the same direction as the gear  870   b , i.e., in the opposite direction of the roller  820   a . As the rollers  820   a ,  820   b  counter-rotate, their protrusions  822  engage the strips&#39; perforations  812 , such that the strips  810   a ,  810   b , together with the enclosed needle  800 , are pulled in the distal direction towards the patient&#39;s body. The strips  810   a ,  810   b  are then forcefully separated from one another, pulled in opposite directions and around the rollers  820   a ,  820   b , while the needle  800  continues its translation in the distal direction and into the body of the patient. 
         [0091]    In some implementations at least one of the gears  870   a ,  870   b  may be a ratchet gear, provided with a pawl, so that the gears can only rotate in one direction, while synchronizing or meshing the rotation of the rollers  8201 ,  820   b . Use of a ratchet gear prevents re-use of the insertion module  80 , which after one use is no longer sterile, with a new needle. It can be appreciated that the insertion module  80  may include other mechanisms to prevent its re-use, such as a non-removable needle head holder, as described above. 
         [0092]      FIG. 10A  is a top view of the insertion module  80 , without the needle and the needle head holder, showing an exemplary arrangement of the rollers  820   a ,  820   b  within the holder  850  (not shown in  FIG. 10A ). In this implementation, in order to avoid the risk of the protrusions  822  of the two rollers bumping into each other as the rollers counter-rotate, which may interrupt the insertion procedure or even cause damage to the strips or the needle, etc., the rollers  820   a ,  820   b  are positioned in opposite directions relative to each other, such that the protrusions of each roller do not face the protrusions of the other roller. Further, the protrusions  822  are disposed circumferentially around each roller, such that each roller  820   a ,  820   b  includes two “rings” of protrusions  822 . In this implementation, opposite each such “ring” there is an annular groove  824  on the other roller, which allows uninterrupted passage of the protrusions  822  as the rollers  820   a ,  820   b  counter-rotate. Since the protrusions  822  do not face each other, the strips  810  in this implementation are provided with four rows of perforations  812 , one row corresponding to each of the four protrusion “rings”. 
         [0093]    In some implementations, each roller  820   a ,  820   b  further includes an additional annular groove  826 , which may be wider and deeper than the annular grooves  824 , and disposed in the transverse center of the roller, in order to allow uninterrupted passage of the convex side of the grooves  814   a ,  814   b  running down the longitudinal center of the strips  810   a ,  810   b , as the strips move in the distal direction and around the rollers  820   a ,  820   b . When the strips  810   a ,  810   b  are attached (e.g., adhered) to each other, the longitudinal grooves  814   a ,  814   b  form together the channel  815  which receives and accommodates the needle therein. In some implementations, instead of the insertion module  80  including two rollers  820   a ,  820   b  each having an annular center groove  826 , the insertion module  80  may include four rollers, each pair of rollers disposed on a single shaft, and spaced apart so as to allow uninterrupted passage of the convex side of the grooves  814   a ,  814   b  therebetween. 
         [0094]      FIG. 10B  is a top view showing an alternative arrangement of rollers  920   a ,  920   b  within the holder (not shown in  FIG. 10B ) of another exemplary insertion module  90 . In this implementation, the rollers  920   a ,  920   b  are spaced apart slightly further than the rollers  820   a ,  820   b  of  FIG. 10A , such that the protrusions  922  of the two rollers  920   a ,  920   b  can be disposed on the rollers such that they face each other without there being a risk of the protrusions of the two rollers  920   a ,  920   b  bumping into each other as the rollers counter-rotate. Accordingly, in this implementation each strip  910   a ,  910   b  has only two rows of perforations  912 , one row on each side of the annular groove  914   a ,  914   b.    
         [0095]    It can be appreciated that, similarly to the implementation shown in  FIG. 10A , in this implementation as well the insertion module  90  may include, instead of two rollers  920   a ,  920   b  each having an annular center groove  926 , four rollers mounted two on each of the shafts  940   a ,  940   b.    
         [0096]    As further shown in  FIG. 10B , in some implementations the bevel gear  930 , the rotation of which results in rotation of the rollers  920   a ,  920   b , may be mounted on shaft  940   b.    
         [0097]    Reference is now made to  FIG. 11 , which is a cross-sectional view showing the protrusions  822  of the roller  820   b  as they engage the perforations  812  of strip  810   b . As described above, in some implementations the protrusions of the two rollers  820   a ,  820   b  do not face each other, i.e., they are disposed in an offset relative to each other. Accordingly, the cross-sectional view of  FIG. 11  depicts only the protrusions of roller  820   b  as they engage the perforations of strip  810   b , and the interface between the protrusions of roller  820   a  and the perforations of strip  810   a  cannot be seen. However, it can be appreciated, that the description below regarding the interface between the protrusions of roller  820   b  and the perforations of strip  810   b  applies equally to the interface between the protrusions of roller  820   a  and the perforations of strip  810   a.    
         [0098]    In some implementations the pitch of the roller  820   b  may be slightly larger than the pitch of the strips  810   b , i.e., the distance between two adjacent roller protrusions may be larger than the distance between two adjacent strip perforations. As a result, the load of pulling the strip falls on the last protrusion  822   a  that remains engaged with the strip  810   b  before the strip disengages from the roller  820   b . This is advantageous since it ensures that the strip  810   b  remains tightly coupled to the roller  820   b  in the section between the first engaging protrusion  822   b  and the last engaging protrusion  822   a , as the roller  820   b  rotates. If the distance between two adjacent protrusions  822  was smaller than the distance between two adjacent perforations  812 , the load of pulling the strip  810  would fall on the first protrusion  822   b  that engages the strip  810   b  as the roller  820   b  rotates. This might result in the strip  810   b  disengaging from the roller  822   b  as it rotates and falling onto the internal surface of the holder  850 , which may result in high friction or even damage to the strip and/or roller and interruption of the insertion procedure. Further, the friction forces may increase in case the strip  810   b  includes an adhesive on its internal surface for attachment to the second strip  810   a , since the remains of the adhesive might cause the strip  810   b  to attach to the internal surface of the holder  850  after the strips are separated from each other. 
         [0099]    Reference is now made to  FIGS. 12A-12C  which show longitudinal cross-sectional views of the insertion device  80  illustrating three different stages of the needle insertion procedure. 
         [0100]      FIG. 12A  shows the insertion device  80  at its initial state, i.e., prior to initiation of the insertion procedure. In the shown embodiment, the device is supplied with the distal end of the strips  810   a ,  810   b  already wound around the rollers  820   a ,  820   b  respectively so as to ensure that the strips detach from one another and roll outwardly and away from each other, together with the counter-rotating rollers  820   a ,  820   b . In some implementations, prior to commencement of the insertion procedure, the tip of the needle  800  is substantially aligned with the distal (bottom) end of the holder  850 . In other implementations the needle tip may be slightly concealed within the holder  850  or it may slightly protrude therefrom. 
         [0101]      FIG. 12B  shows the insertion device  80  after the needle  800  has been partially inserted into the patient&#39;s body, and the strips  810   a ,  810   b  have peeled further away from the needle  800  and around the rollers  820   a ,  820   b.    
         [0102]      FIG. 12C  shows the insertion device  80  at an advanced stage of the insertion process. The needle head holder  860  is now nearing the holder  850  and the rollers  820   a ,  820   b  and the strips  810   a ,  810   b  are further peeled off the needle  800  and wound around the rollers  820   a ,  820   b.    
         [0103]    Reference is now made to  FIG. 13 , which shows a perspective view of an insertion assembly  5  comprising the insertion module  80  coupled to a robotic end effector  1300 . The end effector  1300  includes a frame (or -housing)  1310  for receiving and housing the insertion module  80 , and a motor assembly  1320 , which includes a geared motor  1322  (i.e., motor and planetary gear system) provided with a motor encoder (not shown) for verifying proper function of the geared motor  1322 , a bevel gear  1324 , and a Printed Circuit Board (PCB)  1326 . After the insertion module  80  is coupled to the end effector  1300 , it may be secured to the end effector  1300  using one or more screws  1330 , or any other suitable securing mechanism, such as the mechanism shown hereinafter in  FIGS. 15A-15B . 
         [0104]    In some implementations, the insertion module  80  is a disposable single-use unit, and the end effector  1300  is reusable, i.e., it can be used repeatedly with new disposable insertion modules  80 . In such cases the end effector  1300  is preferably an integral unit of an automated (e.g., robotic) insertion device (not shown in  FIG. 13 ). In other implementations the end effector  1300  may be disposable and separate from the automated insertion device. In such cases the end effector  1300  and the insertion module  80  may be manufactured as a single unit. 
         [0105]    In some implementations, the motor assembly  1320  is an integral component of the end effector  1300 . In other implementations, the motor assembly  1320  may be separate from the end effector  1300  such that it is coupled to the end effector  1300  either before or after the insertion module  80  is coupled to the end effector  1300 . The motor assembly  1320  actuates the insertion mechanism as follows: the geared motor  1322  rotates the bevel gear  1324 , which in turn rotates the bevel gear  830  of the insertion module  80 , to which it is coupled. The bevel gear  830  of the insertion module  80  then rotates the rollers (not shown in  FIG. 13 ) of the insertion module  80 , as described above with regard to  FIGS. 8A and 9 . It can be appreciated that any other applicable method of transferring moment from the motor assembly  1320  to the insertion module  80  may be implemented, and using coupled bevel gears  830  and  1324  is merely one exemplary method. 
         [0106]    In case the motor assembly  1320  is an integral part of the end effector  1300 , the motor assembly  1320  may be connected to the frame  1310  such that the motor assembly  1320  can be moved aside in order to allow proper coupling (and de-coupling) of the insertion module  80  to the end effector  1300 . For example, the interface between the motor assembly  1320  and the frame  1310  may be in the form of a hinge, such that the motor assembly  1320  can pivot about its axis. After the insertion module  80  is introduced into the frame  1310 , the motor assembly  1320  is moved back to its position such that the bevel gear  1324  is properly coupled to the bevel gear  830  of the insertion module  80 . The motor assembly  1320  may be moved back to its position either manually or automatically, e.g., the motor assembly  1320  may include a projection (not shown) which is pressed (or otherwise engaged) by the insertion module  80  as it is being inserted into the frame  1310  of the end effector  1300 , such that coupling the insertion module  80  to the end effector  1300  causes the motor assembly  1320  to return to its place and establish operative coupling with the insertion module  80  (e.g., between bevel gear  830  of the insertion module and bevel gear  1324  of the motor assembly  1320 ). 
         [0107]      FIG. 14  shows an exploded view of the insertion assembly  5  of  FIG. 13 . Shown are the insertion module  80  with the two portions  862  of the needle head holder  860 , which when connected by means of a plurality of screws  864 , for example, secure together the needle head  802  and the proximal end of the strips  810   a ,  810   b . Also shown is the end effector  1300  comprising the end effector frame  1310  and the motor assembly  1320 . As previously discussed, the insertion module  80  is coupled to the end effector  1300  by inserting the insertion module  80  into the end effector frame  1310 , and locking it therein by means of two screws  1330 , for example. The end effector frame  1310  may include a dedicated slot  1312  for receiving the shaft  840   a  such that the bevel gear  830  remains outside the frame  1310  after the insertion module  80  is inserted into the frame  1310 , to enable its coupling to the bevel gear  1324  of the motor assembly  1320 . 
         [0108]      FIGS. 15A-15B  show an alternative mechanism for locking the insertion module  80  within the frame  1310  of the end effector  1300 . In some implementations, the insertion module&#39;s holder  850 , or more specifically, the needle guide portion  857  of the holder, may include a rotatable element  858  including two blades  8582  (which may be manufactured as a single long blade), and a knob  8584  which can be grasped by the user. The end effector frame  1310  may have two slits  1315 , opposite one another, such that the blades  8582  can enter the slits  1315  when the rotatable element  858  is rotated via the knob  8584 . When the rotatable element  858  is in a vertical position, i.e., the blades  8582  are parallel to the needle  800 , as shown in  FIG. 15A , the insertion module  80  can be moved freely in and out of the end effector frame  1310 . When the rotatable element  858  is rotated into a substantially horizontal position, i.e., 90 degrees (or slightly less/more) to the right or to the left, the blades  8582  enter the slits  1315 , as shown in  FIG. 14B , and the insertion module  80  is locked in its place within the frame  1310  such that it cannot be removed from the end effector  1300  by mere pulling. 
         [0109]      FIG. 16  shows the insertion module  80  inserted within the end effector frame  1310 . As described above, as the rollers  820   a ,  820   b  counter-rotate, the protrusions of the rollers engage the perforations of the strips, which causes the strips  810   a ,  810   b  to peel off the needle  800  in opposite directions, around the rollers  820   a ,  820   b , and then exit the insertion module&#39;s holder  850 . In some implementations, the interface between the insertion assembly  5  and the automated insertion device (not shown) may be such that as the strips  810   a ,  810   b  exit the holder  850  and fold outwardly, at least one of the strips, e.g., strip  810   a , might contact other components of the automated insertion device, such as a joint (not shown) connecting the end effector to the automated insertion device, which may interfere with its proper function. Thus, in some implementations the frame  1310  of the end effector  1300  may include a back guide  1318  and the insertion module  80  may include a front guide  880  coupled to the holder  850 , that together prevent the strip  810   a  from folding outwardly toward the automated insertion device by constraining the strip  810   a  to the space between them. In some implementations, there may be provided only a back guide  1318  without a front guide  880 . 
         [0110]      FIG. 17A  shows a perspective view of an exemplary strip  1710 . As previously discussed, as the rollers counter-rotate, the protrusions of the rollers engage the perforations of the strips, resulting in the strips, with the needle enclosed therebetween, being pulled in the distal direction, while the strips detach from each other and peel off the needle in opposite directions and around the rollers. Since the strips  1710  are not flat but have a groove  1714  running along their length, with the convex side of the groove facing the roller, causing the strips to detach from each other and curve outwardly as they are being pulled by the rotating rollers requires a significant amount of energy, which can only be provided by a powerful and relatively large propulsion mechanism (e.g., motor and gears, piston, etc.). Thus, in order to reduce the amount of energy required to detach the strips from each other and cause them to curve outwardly and wind around the rollers, the strips&#39; groove  1714  may include weakened sections  1716  along its length, which facilitate the curving action of the strips without diminishing the strength of the strips  1710 . Preferably, the weakened sections  1716  should be spaced apart according to the natural plastic deformation pattern of the strip  1710 , as determined empirically.  FIG. 17B  is a longitudinal cross-sectional view of the groove  1714  of strip  1710 , showing the wave-like profile of the groove  1714  having weakened areas  1716 , in this case equally spaced weakened areas  1716 . 
         [0111]    Once the medical tool (e.g., needle) is inserted into its desired position within the patient&#39;s body, the physician/clinician may prefer to remove the insertion device/assembly and the entire automated insertion system (when a body-mounted insertion system is employed) from the patient&#39;s body, leaving only the tool in its place. For example, during biopsies in which an introducer is inserted into the patient&#39;s body using the insertion device, once the introducer is in its position, the core of the introducer is removed from the introducer and a biopsy needle is inserted through the introducer and into the target (e.g., tumor). In such cases, the insertion device and/or the automated insertion device may obstruct the clinician&#39;s view or actions such that he/she may prefer to remove all devices/components other than the introducer from the patient&#39;s body. 
         [0112]      FIG. 18A  shows an isometric view of an exemplary modular insertion device/module  180  in its assembled state. The insertion module comprises two parts  182 ,  184  connected along their longitudinal axis. Each part  182 ,  184  includes one portion of the holder  1852 ,  1854 , one strip  1810   a ,  1810   b , one roller (not shown) and one gear  1872 ,  1874  (all numerals respectively). In the initial situation for inserting the needle, with the two parts  182 ,  184  connected, the strips  1810   a ,  1810   b , in the region before being fed to the rollers, are attached to each other or held together, and their coupled grooves  1814   a ,  1814   b  together form the channel that receives and encloses the needle  1800 . 
         [0113]      FIG. 18B  shows an isometric view of the exemplary modular insertion device/module  180  in its disassembled state. One of the parts, e.g. part  182 , may have a plurality of protrusions  1882 , and the second part, e.g. part  184 , may have a plurality of corresponding slots/niches  1884  (only one slot/niche  1884  is visible in  FIG. 18B ) for receiving the protrusions  1882  when the two parts  182 ,  184  are connected. It can be appreciated that any other suitable method for connecting the two parts of the insertion module may be implemented. Since the needle  1800  is enclosed within the channel formed between the strips  1810   a ,  1810   b , but it is not connected to the strips  1810 ,  1810   b , or to any other component of the insertion module  180 , once the needle  1800  has reached its target, the user can disconnect the two parts  182 ,  184  from one another, thus detaching the strips  1810   a ,  1810   b  from one another and away from the needle  1800 , without applying on the needle  1800  any major forces which may cause it to move from its position. 
         [0114]    It is appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and subcombinations of various features described hereinabove as well as variations and modifications thereto which would occur to a person of skill in the art upon reading the above description and which are not in the prior art.