Abstract:
This document relates to catheter-based therapeutic apparatus and methods for directing therapy within the body of a subject. This document also encompasses a control handle comprising a steering assembly and a delivery assembly suitable for use in conjunction with the catheter-based therapeutic apparatus to provide steering and fine positional control of the catheter tip.

Description:
FIELD 
       [0001]    The present invention relates to the field of steerable tip catheters and devices for their control, in particular, steerable tip catheters and handles for their control for delivering a therapeutic agent into a substrate. 
       BACKGROUND OF THE INVENTION 
       [0002]    Cardiovascular diseases is a leading cause of morbidity and mortality worldwide and in contrast to tissues with high reparative capacity, heart tissue is vulnerable to damage that is irreparable by the normal mechanisms of the body. The prevention and treatment of these diseases are thus a major issue and numerous clinical efforts are being made to improve the care and treatment of cardiac disorders. 
         [0003]    Regenerative medicine is one current research method for reducing dysfunction of organs, such as the heart, for example (Sherman,  Cellular Therapy for Chronic Myocardial Disease: Nonsurgical approaches, Basic Appl. Myol.  13(1) 11-14). This treatment involves the injection of therapeutic solutions directly into the organ through devices such as injection catheters. 
         [0004]    Heldman et al., Cell Therapy for myocardial infarction: Special delivery,  Journal of Molecular and Cellular Cardiology,  2008, 44, 473-476, describes several such delivery devices for use in the heart along with their disadvantages listed according to type of injection (epicardiac, endocardiac, intracoronary or intravenous). 
         [0005]    Steering and fine positional control of the tip of a delivery device such as an injection catheter is of the utmost importance when it is to be used to direct therapy or deliver a therapeutic agent to a predetermined site within the body of a patient. It is imperative that the operator/user of the apparatus is able to undertake functions such as steering of the device and application of therapy concurrently. 
         [0006]    Most existing systems currently available require that steering and application of therapy occur consecutively—i.e. as a first step the functional elements of the tip portion are located at the appropriate site within the body of the subject and then therapy is applied. This two-step approach is particularly limiting in dynamic systems, such as the heart, where the movement of the underlying tissues and vessels can displace the tip and result in incomplete or incorrect delivery of therapy. 
         [0007]    To mitigate such effects using prior art devices it has been known for two operators/clinicians to use these devices at the same time thereby adopting an approach of three or four-handed operation. Since most prior art devices are not designed or marketed for use three or four-handed not only is this unwieldy in the operating theatre, but it results in an increased risk of error in a surgical procedure. Where multiple operators of a device are required the likelihood of confusion or misdirection is increased, which leads to an increased burden of training and specialisation for clinicians using such devices. 
         [0008]    EP 0787019 B1 relates to a steerable catheter and control handle for use in endocardial treatment of the heart. The handle comprises a rotatable thumbwheel mounted at the distal end of the handle for deflection of a catheter tip. 
         [0009]    EP 1323448 A2 describes a control handle for use with a steerable catheter. The handle comprises a rotatable thumbwheel mounted at the distal end of the handle for deflection of a catheter tip. 
         [0010]    WO 02/087676 A2 describes a steerable catheter and control handle for use in endocardial mapping and/or ablation procedures. The handle comprises a rotatable thumbwheel mounted perpendicular to the longitudinal axis of the handle for deflection of a catheter tip. 
         [0011]    Therefore, there remains a need in the art for a catheter apparatus capable of allowing a lone operator a greater level of integration and control than has been achievable with the therapeutic catheters forming the current state of the art. In particular there is a need for a catheter that can integrate both improved flexure and steerability together with functionality that enables delivery of a pharmaceutical preparation to a desired site within the body of a recipient. 
         [0012]    These and other uses, features and advantages of the invention should be apparent to those skilled in the art from the teachings provided herein. 
       SUMMARY OF THE INVENTION 
       [0013]    In its primary aspect the invention provides an apparatus suitable for use as a percutaneous or endoscopic catheter comprising:
       a. an elongate shaft that comprises a proximal end and a distal end, wherein the elongate shaft defines at least one central lumen;   b. at least one steering member that is located within the at least one central lumen and extends along the elongate shaft from the proximal end to an anchor point at the distal end;   c. a steering assembly that is located at or near to the proximal end of the elongate shaft; and   d. a handle that comprises a proximal end and a distal end;       
 
         [0018]    wherein the steering assembly is comprised at the distal end of the handle and at least a portion of the steering member passes through the central axis of the steering assembly. Typically the steering member of the apparatus comprises a steering wire that is slidably located within an outer conduit. Suitably, the outer conduit consists of a hypotube. The steering assembly may suitably comprise a mechanism for controlling movement of the outer conduit relative to the steering wire, thereby imparting a bending force to the elongate shaft at its distal end. 
         [0019]    The described arrangement places the steering controls at the distal end of the handle and, optionally, opposite to additional controls comprised within the handle, such as pharmaceutical delivery controls. This arrangement is particularly ergonomic allowing the operator to use the apparatus, if desired, in a palm-up configuration with the steering controls seated between thumb and forefinger which provides very fine motor control of the distal end of the elongate shaft. In addition, this arrangement frees the spare hand of the operator to manage and control the deployment of and delivery of any therapeutic compositions as and when appropriate. The arrangement of steering and any additional delivery functionalities at opposing ends of the handle thereby reduces muscle fatigue and advantageously allows for single user (one or two handed) operation rather than cumbersome and awkward two user (four handed) operation. 
         [0020]    Suitably, the steering assembly comprises a slidable carriage that is arranged so as to impart force on the outer conduit but not on the steering wire when the carriage is moved axially. Optionally, the steering assembly comprises a slidable carriage that is arranged so as to impart force on the steering wire but not on the outer conduit when the carriage is moved axially. The movement of the carriage may be mediated via engagement with a threaded bar. The rotation of the threaded bar is suitably controlled via a wheel or dial. Typically, the wheel is positioned at the distal end of the handle and the steering assembly is located proximally to the wheel. Alternatively, movement of the carriage can be controlled by a slider arrangement. 
         [0021]    The apparatus may suitably further comprise a therapeutic device. Typically, the therapeutic device comprises at least one penetrating member, wherein the penetrating member extends along the elongate shaft from the proximal end to the distal end, and wherein the penetrating member is capable of being advanced in distal direction beyond the distal end of the elongate shaft. The penetrating member suitably comprises a hollow needle. 
         [0022]    Suitably, the handle of the apparatus further comprises a delivery assembly, wherein the hollow needle is in fluid communication with the delivery assembly. The delivery assembly may suitably be located at the proximal end of the handle. The handle may be suitably configured such that the delivery assembly and the steering assembly are placed in a substantially linear arrangement along the central axis of the handle. Typically, the delivery assembly is arranged to facilitate delivery of a pharmaceutical composition. Optionally, the delivery assembly is arranged to facilitate delivery of a cellular preparation. 
         [0023]    A second aspect of the invention provides a handle, suitable for use in conjunction with a percutaneous or endoscopic therapeutic catheter, the handle comprising:
       a. a housing, wherein the housing is substantially elongate in configuration and comprises a proximal portion and a distal portion;   b. a steering assembly that is located in the distal portion of the housing, wherein the steering assembly is adapted to cooperate with and control the steering mechanism of a catheter;   c. a delivery assembly that is located in the proximal portion of the housing, wherein the delivery assembly is adapted to control application of therapy via the catheter;       
 
         [0027]    wherein the handle is configured such that the delivery assembly and the steering assembly are placed in a substantially linear arrangement along the central longitudinal axis of the housing. 
         [0028]    Typically, the steering assembly of the handle controls movement of the steering mechanism of the catheter. The steering mechanism suitably comprises a steering wire that is slidably located within an outer conduit, and the steering assembly controls movement of the outer conduit relative to the steering wire, thereby imparting a bending force to catheter that facilitates steering of the catheter when in use. 
         [0029]    A third aspect of the invention provides a percutaneous catheter that comprises the afore-mentioned handle. 
         [0030]    A fourth aspect of the invention provides an endoscopic catheter that comprises the afore-mentioned handle. 
         [0031]    A fifth aspect of the invention provides a method for directing therapy within the body of a subject comprising using the catheter-based therapeutic apparatus of the present invention. 
         [0032]    Suitably, the method for directing therapy within the body of a subject comprises a catheter-based therapeutic apparatus that is controlled and manoeuvred via the handle of the present invention. Typically, the therapy comprises delivery of a pharmaceutical composition. Optionally, the therapy comprises delivery of a cellular preparation. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0033]    The invention is further illustrated by the accompanying figures in which: 
           [0034]      FIG. 1  is an oblique view of the handle assembly of one embodiment of the invention (a) shows an unexploded view of the housing, (b) is exploded so as to show the internal arrangement of the handle assembly; 
           [0035]      FIG. 2  is a side sectional view of the handle assembly of  FIG. 1 , the axis of the handle assembly is shown with distal at the bottom and proximal at the top of the figure; 
           [0036]      FIG. 3  shows the distal tip portion of an embodiment of the invention with a curved hollow needle in the deployed state, (a) shows the view with a distal stopper piece in place and (b) shows the view with the stopper removed to reveal the steering wire and the central lumen; 
           [0037]      FIG. 4  is a side sectional view of the control wheel assembly at the distal end of the handle; 
           [0038]      FIG. 5  shows close up sectional view of the steering assembly and in particular the carriage arrangement according to one embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0039]    All references cited herein are incorporated by reference in their entirety. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. 
         [0040]    The invention provides for a medical device comprising an elongated shaft assembly, typically in the form of a catheter that comprises a functional element at its distal tip and a user interface at the proximal terminus. In the art the user interface is sometimes referred to as a handle, handle assembly or hub. 
         [0041]    Prior to setting forth the invention, a number of definitions are provided that will assist in the understanding of the invention. It should be appreciated that the term ‘comprising’ as used herein is intended to mean including but not limited purely to any accompanying features. 
         [0042]    As used herein the terms distal and proximal are used to refer to orientation along the longitudinal axis of the device. Since the devices of the invention are elongate in nature and conform to a single dimension, in use the distal direction refers to the end of the device furthest away from the operator and the proximal direction the end of the device closest to the operator. It should be noted that the term proximal should not be confused with the term ‘proximate’, which adopts its conventional meaning of ‘near to’. 
         [0043]    In its broadest configuration the apparatus of the invention comprises an elongate shaft assembly which is attached to a handle assembly. The elongate shaft is suitably configured for percutaneous use, such as via intravascular, endoscopic or laparoscopic modes that involves introduction into a hollow anatomical vessel or duct within the body of a subject animal. The handle assembly remains outside—i.e. external to—the body of the subject. In a specific embodiment of the invention the elongate shaft is a catheter, suitably comprising a tube portion that may define one or more lumens located coaxially within the shaft. The catheter may be adapted for use with an associated guidewire in convention over-the-wire (OTW) or monorail configurations. In embodiments where the catheter is adapted for use with a guidewire, the catheter will further comprise an additional lumen that is adapted to accommodate a guidewire. Any such guidewire may be prelocated within the subject in order to facilitate placement of the device when in use. 
         [0044]    The device of the present invention is suitable for intravascular use, in particular intracoronary use. However, in other embodiments of the invention the device may be used within the blood vessels of the abdomen, the head and neck or limbs, or within the ducts of the gastrointestinal or genito-urinary tracts. 
         [0045]    In a specific embodiment of the invention the apparatus is configured so as to provide a delivery catheter of the type disclosed in Applicant&#39;s International Patent Application published as WO-A-2010/125166, and marketed under the brand names C-CATH® and C-CATH EZ ® (Cardio3 BioSciences SA, Mont-Saint Guibert, Belgium). 
         [0046]    Typically, the apparatus of the invention is operated according to three main phases of therapy: an insertion phase, a therapy phase and a removal phase. The insertion phase includes the intravascular/endoscopic/laparoscopic insertion of the device and the location of the device to the site of treatment where therapy is to be administered. The therapy phase includes administering pharmaceutical compositions or cellular preparations where required. The removal phase includes the withdrawal of the device from the site of treatment; usually back along the initial insertion route. It will be appreciated that the therapy phase may be repeated several times before the removal phase commences. 
         [0047]    According to one embodiment of the invention the elongated shaft is provided with a central lumen that extends along its entire length. The elongate shaft of embodiments of the invention are suitably constructed as catheters in a variety of sizes typically ranging from about 0.15 mm up to about 4 mm in diameter (corresponds to French sizes 0.5 to 12). The central lumen provides a conduit which may allow engagement with a prelocated guidewire. Alternatively, the central lumen provides a conduit within which the penetrating member is housed. The central lumen may extend entirely along the shaft such that the distal terminus comprises an aperture allowing fluid communication between the central lumen and the hollow anatomical structure within which the shaft is located. In such embodiments of the invention the penetrating member, when advanced out of the central lumen, may be deployed along a path that is at least in part coaxial with the axis of the central lumen. In an embodiment of the invention, the central lumen is formed from a polymer liner that sits coaxially within the elongate shaft. Suitably the polymer liner is comprised of a material such as a fluoropolymer, for example PTFE. In this embodiment of the invention the distal portion, at least, of the polymer liner may be linked or otherwise fixed to the distal part of the elongate shaft and the main portion of the polymer liner is allowed to move freely within and with respect to the elongate shaft. Advantages of this arrangement are that the flexibility of the shaft is improved and deployment and consistency of the penetrating member is easier to control. Embodiments of the invention permit for location of the central lumen centrally within the body of the elongate shaft or at a position that is radially offset from the central longitudinal axis 
         [0048]    It will be appreciated that alternative configurations may also be adopted in which the central lumen may be diverted radially at a position proximal to the distal terminus of the elongate shaft. Such configurations permit embodiments of the invention in which the penetrating member is diverted radially outwardly from the device when extended out of the central lumen. In this embodiment of the invention the central lumen will create an aperture in the side of the elongate shaft rather than at its terminus. Where the aperture is located in the side of the elongate shaft but close (proximate) to the distal terminus the region defined by the distal terminus and the adjacent radially located aperture is referred to collectively as the distal tip portion of the elongate shaft. The distal tip portion of the elongate shaft may comprise a radiopaque material or coating so as to facilitate visualisation during surgical procedures when using X-rays. The shaft may further comprise one or more echogenic surfaces to further facilitate use with ultrasound visualisation (e.g. IVUS) technologies. 
         [0049]    The penetrating member may be a retractable hollow needle or stylet formed from a suitable material including polyether ether ketone (PEEK), carbon fibre loaded liquid crystalline polymer, tungsten carbide polyimide, stainless steel, gold, platinum, shape memory alloy (including NiTinol) or other suitable surgically compatible metal alloys. Typically, the penetrating member is formed from a radiopaque material so as to facilitate visualisation during surgical procedures when using X-ray guidance. The penetrating member may further comprise one or more echogenic surfaces to further facilitate use with ultrasound visualisation (e.g. IVUS) technologies. The penetrating member is provided with a sharp tip at its distal end, which is used to puncture and penetrate tissue at the site of treatment. The lumen of the penetrating member allows for administration of substances, including cell preparations and pharmaceutical compositions, to the site of treatment through the lumen of the penetrating member. The lumen of the penetrating member may also be used as an aspiration channel to extract fluids from the site of treatment and/or to take a tissue biopsy. 
         [0050]    An exemplary device of the invention comprises an elongate shaft which encloses at least one central lumen. The central lumen extends along substantially the entire length of the elongate shaft and provides a conduit for delivery and location of the penetrating member. In one embodiment of the invention, the elongate shaft may also comprise at least one additional lumen located adjacent to the central lumen in a coaxial arrangement. The at least one additional lumen may accommodate one or more steering members. Suitably, the steering member comprises a pull wire that extends along the entire length of the elongate shaft and allows the user to apply a steering action particularly at the distal tip of the elongate shaft via the well-known Bowden cable method of transmitting movement. In a further embodiment of the invention the elongate shaft comprises only a central lumen that accommodates both the penetrating member and one or more adjacent steering members. 
         [0051]    The elongate shaft is suitably constructed from a polymeric material such as a silicone rubber or a polymer including thermoplastic elastomer, PEEK, polyimide, high density polyethylene (HDPE), Pebax, and/or nylon; or composites thereof. All or a portion of the shaft may also comprise a low friction or lubricious coating that may, for example, include a fluoropolymer such as a PTFE or parylene. 
         [0052]    Steering and fine positional control of the distal tip of the elongate shaft is of particular importance where the apparatus of the invention is to be used to direct therapy or deliver a therapeutic agent to a predetermined site within the body of a subject (e.g. a patient). By “steering” it is meant that the distal tip of the apparatus may be diverted away from the longitudinal axis of the device to an extent as required and controlled by the operator. Steering is also commonly termed within the art “flexure” or “bending”. It is imperative that the operator/user of the apparatus is able to undertake functions such as steering of the device and application of therapy as concurrently as possible. Most existing systems currently available require that steering and application of therapy occur in very distinct consecutive phases—i.e. as a first step the functional elements of the distal tip portion are located at the appropriate site within the body of the subject and then therapy is applied. This two-step approach can introduce time delays and is particularly limiting in dynamic systems such as the heart where movement of the underlying tissues and vessels can displace the distal tip portion and result in incomplete or incorrect delivery of therapy. To mitigate such effects using prior art devices it has been known for two operators/clinicians to use these devices at the same time thereby adopting an approach of three or four-handed operation. Since most prior art devices are not designed or marketed for use three or four-handed not only is this unwieldy in the operating theatre, but it results in an increased risk of error in a surgical procedure. It is of particular advantage, therefore, that the apparatus of the present invention is enables a single operator a greater level of integration and control than has been previously achievable. 
         [0053]    Steering and fine positional control is mediated via the handle assembly which is located at and integrated with the proximal end of the elongate shaft.  FIG. 1(   a ) shows an oblique view of an embodiment of the handle assembly  100 , which comprises a housing  101 . Located adjacent to and abutting distal end of the housing  101  is a control wheel  121 , and at the proximal terminus of the handle is located a therapy delivery member  140 . The elongate shaft  200  passes through the control wheel  121  into the housing  101 , as is evident in the exploded view of the handle assembly  100  in  FIG. 1(   b ). 
         [0054]      FIGS. 3(   a ) and ( b ) show the distal tip portion  210  of the elongate shaft  200  in one particular configuration of the apparatus of the invention. It will be appreciated that the handle assembly  100  is not limited to control of or use with this particular embodiment of the invention and may be compatible with other arrangements.  FIGS. 3(   a ) and ( b ) show a delivery needle  211  in a deployed configuration extended outwardly from the shaft  200 . During the insertion phase the needle  211  is stowed within the lumen  214 . The needle  211  may be housed within a sheath  215  to facilitate delivery and enable fluid communication between the needle and the delivery member  140  located within the handle assembly  100 . The elongate shaft  200  also comprises at least one steering wire  213  which is also located within the lumen  214  and extends along the entire length of the shaft  200 . The steering wire  213  is typically comprised within a conduit such as a hypotube  213   a  that allows for slidable movement of the wire  213  relative to the hypotube  213   a.  The hypotube  213   a  may be fabricated from a metal, such as stainless steel, or from a any other material featured with similar rigidity. The distal end of the hypotube  213   a  is rigidly connected to the distal end of the elongate shaft  200  at a point or plurality of points proximal to the region to be steered/flexed The distal terminus of the lumen  214  is enclosed by a stopper  212  which provides an anchor point for the distal end of the steering wire  213 . The stopper  212  comprises at least one aperture to allow passage of the needle  211  therethrough upon deployment. 
         [0055]    A side sectional view of the handle assembly  100  is shown in  FIG. 2 . The elongate shaft  200  passes along the central axis of the assembly  100  into the housing  101 . The proximal terminus of the shaft  200  is located in the distal end of the housing  101  within a steering mechanism  120 , which is described in more detail below. 
         [0056]    In the embodiment shown, the steering wire  213  extends beyond the steering assembly  120  and is rigidly fixed at its proximal end to the body of the housing  101 . In an alternative embodiment (not shown), the proximal end of the steering wire  213  is rigidly fixed to a member which is axially slideable relative to the handle assembly  100 . In this embodiment, the steering assembly is rigidly fixed to the body of the housing whilst the steering wire  213  is axially movable relative to the steering assembly. 
         [0057]    The sheath  215  also extends beyond the steering mechanism  120  towards the proximal end of the housing  101  where it engages with the delivery mechanism  130 . The delivery mechanism  130  comprises a delivery member  140  that controls deployment of the needle  211  through a user operated push-pull plunger arrangement. Located coaxially with the delivery member  140  is means for connecting a therapy administration device  150  that may be suitably in the form of a piston, syringe or dosage pump that is in fluid communication with the lumen of the sheath  215  and, thus, the hollow needle  211 . The connector  150  for the administration device is operated by the user to introduce, for example, a therapeutic composition into the lumen of the needle  211  and consequently into the subject at the site of therapy. The connector  150  may comprise one or more ports (e.g. a Luer Lock) to facilitate loading of a therapeutic composition into the device, either before or during the therapeutic procedure. 
         [0058]    The steering mechanism  120  of the handle  100  is located at the distal end of the housing  101 . Steering/ flexure of the distal end is achieved by axial movement of the elongate shaft  200 /hypotube  213   a  relative to the steering wire  213 . In the embodiment shown, this axial movement is achieved through rotation of the control wheel  121  which in turn is translated into axial movement via a threaded bar  125 .  FIG. 4  shows a sectional view of the control wheel  121  with the elongate shaft  200  passing along the central axis. In the embodiment shown in  FIG. 4 , the control wheel is formed from two symmetrical plastic pieces that in combination form a bulb shaped component. It will be understood, however, that alternative configurations of the control wheel  121  may be contemplated by the skilled addressee and may include use of a slider arrangement or a lever to impart control of movement. The control wheel  121  is rotatable about the elongate shaft  200  in both clockwise and anti-clockwise directions. The proximal end of control wheel  121  is formed into a moulding that sits within recess  124  at the distal end of the housing  101 . The moulding comprises a plurality of surfaces that enable a secure engagement between the control wheel  121  and the recess  124  but still permit the control wheel  121  to rotate freely. The rotation of the control wheel is further facilitated by the presence of a bushing  123  that forms a slidable surface around the distal entrance to the recess  124  in which the control wheel  121  is seated. The interior surface of the control wheel  121  comprises a recess into which is located a nut  122 . The nut  122  is fixed to the control wheel  121  such that rotation of the control wheel controls rotation of the nut  122 . The proximal end of the nut  122  is linked to a hollow threaded bar  125  that extends proximally to a point where it abuts a termination disk  128 . The termination disk is comprised within carriage assembly  126  that is threaded onto the bar  125  and runs along rails  108  formed on the interior surface of the housing  101 . The termination disk  128  sits between proximal and distal carriage components  129   a - b  which are held together by screws  129   c.    
         [0059]    As can be seen in  FIG. 5 , the sheath  215  and the steering wire  213  extend along the lumen of the hollow bar  125  to a point proximal to the termination disk  128  at which point they diverge as described above. However, the hypotube  213   a  of the steering wire  213  terminates flush with the proximal face of the termination disk  128  such that during advancement of the carriage  126  force is translated from the proximal to the distal end of the hypotube  213   a.  This prevents the region of the elongate sheath  200  between these two points from flexing during steering. The carriage assembly comprises a limiter nut  127   a  and spacer  127   b  at the distal end in order to limit the extent of movement of the carriage assembly  126  along the bar  125 . 
         [0060]    In use, the operator of the device is able to control steering of the distal tip  210  via rotation of the control wheel  121 , the movement of which is transmitted to the threaded bar  125  and, thus, to the carriage assembly  126 . Hence, rotational movement of the control wheel  121  is converted to translational movement of the carriage assembly  126  along the axis of the handle  100 . As the carriage assembly  126  moves along the rails  108  in a distal direction in response to rotation of the control wheel  121 , the termination disk  128  is brought to bear upon the hypotube  213   a  causing relative movement of the steering wire  213  to the hypotube  213   a.  By virtue of the foreshortening effect that is caused the movement is transmitted to the fixing point between the steering wire  213  and the stopper  212  in the distal tip  210  of the elongate sheath  200 . In this way, small rotational movements of the control wheel  121  result in movement of the tip  210  in a highly controlled manner. The present arrangement allows for the distal tip  210  to be diverted (i.e. curled) by an angle of in excess of 180°, typically over 230°. Overall rotation of the elongate sheath  200  is achieved by rotation of the handle  100  as a whole about the longitudinal axis of the device. 
         [0061]    The described arrangement places the steering controls at the distal end of the handle  100  and opposite to the delivery controls. This arrangement is particularly ergonomic allowing the operator to use the apparatus, if desired, in a palm-up configuration with the control wheel  121  seated between thumb and forefinger which provides very fine motor control of the distal tip  210 . In addition, this arrangement frees the spare hand of the operator to manage and control the deployment of the needle  211  and delivery of therapeutic compositions as and when appropriate. The arrangement of steering and delivery functionalities at opposing ends of the handle  100  thereby reduces muscle fatigue associated with prior art handles and advantageously allows for single user (two handed) operation rather than cumbersome and awkward two user (three or four handed) operation. 
         [0062]    The steering and handle assembly as currently described is not limited to use in delivery catheters. It will be appreciated by the skilled person that the handle assembly can be adapted for use in any catheter, endoscope or laparoscope that requires operator execution of fine control and steering ability over the distal tip region. Hence, it is appropriate for the handle of the invention to be adapted for use with ablation catheters (e.g. radiofrequency, irreversible electroporation or laser ablation catheter devices), medical imaging catheters (e.g. IVUS or other ultrasound imaging catheters), dilation catheters (e.g. balloon dilation angioplasty or stent delivery catheters). In non-delivery catheter arrangements the delivery assembly  140  is simply replaced with the desired appropriate control mechanism to match with the altered functional configuration at the distal tip  210 . By way of non-limiting example, if the steering assembly is to be used in conjunction with a balloon dilation angioplasty catheter, the controls for deploying the expandable balloon would be located at the proximal end of the handle with the steering assembly as described above located at the distal end of the handle. 
         [0063]    It should be understood that the different embodiments of the invention described herein can be combined where appropriate and that features of the embodiments of the invention can be used interchangeably with other embodiments where appropriate. 
         [0064]    Although particular embodiments of the invention have been disclosed herein in detail, this has been done by way of example and for the purposes of illustration only. The aforementioned embodiments are not intended to be limiting with respect to the scope of the appended claims, which follow. It is contemplated by the inventors that various substitutions, alterations, and modifications may be made to the invention without departing from the scope of the invention as defined by the claims.