Patent Publication Number: US-11648396-B2

Title: Extractor for removing a lead from a patient

Description:
This application is a continuation of application Ser. No. 15/655,773, filed on Jul. 20, 2017, now U.S. Pat. No. 10,532,207, which is a continuation of application Ser. No. 14/455,921, filed Aug. 10, 2014, now U.S. Pat. No. 9,889,294, which claims the benefit of U.S. Provisional Application No. 61/869,729 filed Aug. 25, 2013. The entire contents of each of these applications are incorporated herein by reference. 
    
    
     BACKGROUND 
     Technical Field 
     The invention relates to an extractor for removing an implanted lead from a patient, such as a cardiac pacing lead. 
     Background of Related Art 
     Recently, implantation of cardiac pacing devices has become a standard medical intervention for correcting cardiac rhythm thereby reducing patient&#39;s health complaints due to an abnormal cardiac condition. 
     The cardiac pacing device, such as a pacemaker, includes one or more electrical leads which supply a due electrical stimulus from the pacemaker or implantable cardioverter defibrillator to the heart muscle. These electrodes are implanted in the heart tissue, i.e., in a vein in the heart such as the superior vena cava or subclavia vena which may take place during open heart surgery. The distal portion of the electrical leads may include anchors for affixing the electrode lead inside the heart muscle. The electrode wire is covered with a suitable layer of insulator for electrical safety in operation. The leads can have an externally threaded tip to screw into the tissue. 
     During use, the electrical lead may be damaged or may need to be replaced due to maintenance considerations. This procedure is usually complicated by the fact that during the time the lead has dwelled inside the body, it has grown into a scar tissue as well as it may be covered by tissue as the result of tissue ingrowth. Tissue ingrowth can occur along various portions of the lead. It is appreciated that both phenomena make it difficult to remove the electrode lead from the heart tissue. This is especially the case since the vein makes a curve from the pacemaker to the heart and the lead is often attached to the vein at this curve, thereby making release difficult. 
     Through the years different attempts have been made to provide a suitable lead extractor device which is capable of removing an implanted electrical lead without causing damage to the patient. 
     Originally, lead extractors were mechanical devices operable by a cardiac surgeon to free the leads from the surrounding tissue for removing them from the heart. The disadvantage of such devices is that a mechanical force is initially applied in the region of a manifold of the lead extractor and has to be suitably transferred to a distant location along the lead for freeing it from the tissue. Usually the lead extraction is carried out using a subclavian approach or femoral approach. In both approaches a sheath is placed over the lead and is threaded over the lead to reach the distal portion, i.e., the tip, of the lead. However, it has been clinically found that such mechanical approach has a high risk of undesirable disruption of the tissue of the patient when attempting to free the implanted electrode lead from the heart muscle. Also, the hardened tissue around the lead can in some instances make placement of the sheath difficult. 
     A particular version of a lead extractor is disclosed in U.S. Pat. No. 4,574,800, which is arranged to remove implanted leads from a patient by grasping the lead substantially close to its implantation position. Accordingly, this extractor device includes an elongate tubular member arranged to slide into and through a longitudinal lumen of the cardiac pacing lead. The distal portion of the elongate tubular member comprises a protrusion member adapted to provide a wedging surface. The wedging surface is effected by a tapering proximal surface of the protrusion member. The proximal tapering surface may take the form of a spherical or a conical section. The elongate tubular member further includes a spherical gripping member arranged to engage with the lead. When the proximal end portion of the elongate member is pulled with a substantial force, for example, by suitable actuation of the handle, the protrusion member forms a flared distal end section of the elongate tubular member. The elongate tubular member has a length such that it projects beyond the proximal end of the cardiac lead when the known extractor is fully inserted into the lead. In use, the extractor assembly is inserted into and through the cardiac pacing lead until the protrusion member abuts the proximal end of the implanted electrode. Afterwards, the protrusion member is activated to cause the distal portion of the tubular member to wedge. The wedged portion comes into frictional engagement with the inside surface of the distal portion of the cardiac pacing lead. Finally, a pulling force is applied to the proximal portion of the elongate tubular member, which is transmitted to the distal portion of the elongate tubular member towards the flared portion. This pulls the cardiac pacing lead from its dwelling. 
     Although in the foregoing system&#39;s excessive force to the electrode wire and its insulator sheath may be avoided, the pulling forces, which are transferred from the proximal end of the lead extractor, may cause undesirable local damage to the tissue. Additionally, since the lead extractor is provided inside the lumen of the lead, it has to meet stringent constraints regarding its permissible dimensions. This limits the possibilities of optimization of the lead extractor in terms of mechanics. 
     Other prior art attempts to extract leads involve inserting a tube over the lead and drilling down with the tube to separate surrounding tissue from the external surface of the lead to free the lead. Still other prior art methods include utilizing lasers or electrosurgical energy, such as radiofrequency energy at the end of a catheter to sever the tissue. 
     The need exists for a simplified and less traumatic approach to removing leads, such as cardiac leads, from a patient. 
     SUMMARY 
     The present device provides an improved lead extractor which is capable of secure removal of the implanted leads, such as cardiac leads, causing minimum damage to the patient&#39;s tissue. The lead is clamped by the extractor and incremental relative movement of the lead and retractor moves the lead within the extractor lumen as tissue surrounding the lead is cut (dissected) by the extractor. 
     In one aspect, the present invention provides an extractor for removing an implanted lead from a patient, the extractor comprising a proximal portion, a distal portion, a lumen dimensioned to receive the lead therein, and a cutter at the distal portion of the extractor for cutting tissue adjacent the implanted lead. A first clamping member is spaced proximally of the cutter, the first clamping member movable between a clamping position to clamp the lead and an unclamping position to unclamp the lead, and the extractor and lead are relatively movable to remove the lead. 
     In some embodiments the extractor further includes a movement mechanism operatively associated with the first clamping member, the movement mechanism movable between proximal and distal positions to alter an orientation of the first clamping member to move it between the clamping and unclamping positions. 
     In some embodiments, the first clamping member includes a first pivotable ring member having an opening therethrough to receive the lead therethrough, wherein the first pivotable ring member is tiltable relative to a longitudinal axis of the lead to apply a clamping force on the lead to clamp the lead when in a more tilted position. The extractor can further include a second pivotable clamping member, and the second clamping member can comprise a second ring member axially spaced from the first ring member and having an opening therethrough to receive the lead therethrough and tiltable relative to the longitudinal axis of the lead to apply a clamping force on the lead to clamp the lead when in a more tilted position. In some embodiments, the first and second pivotable ring members are alternatively movable between the clamped and unclamped positions so that the first pivotable ring member clamps the lead while the second pivotable ring member is in an unclamped position to allow relative movement of the lead therethrough and the second pivotable ring member clamps the lead while the first pivotable ring member is in an unclamped position to allow relative movement of the lead therethrough. 
     In some embodiments, the extractor further includes a housing and a carrier slidably mounted within the housing, the first clamping member positioned within the carrier, and axial movement of the carrier moves the first clamping member axially. In some embodiments, movement of the carrier in a proximal direction moves the lead further in the lumen of the extractor. In some embodiments, the extractor further includes a second clamping member positioned distal of the carrier. 
     In some embodiments, the extractor includes a second clamping member, wherein the first clamping member has a first hinge and the second clamping member has a second hinge, the first and second hinges radially spaced from a longitudinal axis of the extractor and lying on opposing sides of the longitudinal axis of the extractor. 
     The extractor can further include a cable operatively associated with the first clamping member, wherein distal movement of the cable advances the first clamping member distally and proximal movement of the cable retracts the first clamping member proximally. 
     The extractor can include a second clamping member and a stop to limit distal travel of the second clamping member, wherein the stop can be overridden to release the first and second clamping members. 
     In some embodiments, the cutter is both axially movable and rotatable concurrently with axial movement of the first clamping member. In some embodiments, the extractor further comprises an outer tube or housing, the cutter positioned at a distal portion of the outer tube and the outer tube having a helical slot for rotational movement of the outer tube. 
     In some embodiments, the extractor includes a second clamping member, wherein movement of the extractor is effected by alternate movement of the first and second clamping members to incrementally move the lead and extractor relative to one another as the tissue is cut, e.g., severed and/or dissected, by the cutter. 
     In some embodiments, the movement mechanism is controlled by an external power source connected to the movement mechanism. 
     In some embodiments, a flexible sheath is provided which is rotatable with respect to the extractor to unscrew a distal tip of the lead from tissue. 
     In another aspect, the present invention provides an extractor for removing an implanted lead from a patient, the extractor having a proximal portion, a distal portion, a lumen to receive the lead therein, and a cutter at the distal portion for cutting tissue adjacent the implanted lead. The extractor and lead are incrementally relatively movable to swallow the lead as tissue is cut by the cutter adjacent the lead. 
     In some embodiments, the extractor includes a first clamping member, and the cutter rotates to cut tissue as the position of the first clamping member changes. In some embodiments, the first clamping member is movable between unclamped position and clamped positions, and in the clamped position retraction of the first clamping member causes swallowing of the lead by the extractor. In some embodiments, the first clamping member is tiltable relative to a longitudinal axis of the extractor to move between the clamped and unclamped positions. 
     The extractor can include in some embodiments a second clamping member movable between unclamped position and clamped positions, and in the clamped position retraction of the second clamping member causes swallowing of the lead by the extractor, the first and second clamping members alternately moved between clamped and unclamped positions. The extractor can further include a second clamping member movable between unclamped and clamped positions, wherein the first clamping member has a first hinge and the second clamping member has a second hinge, the first and second hinges radially spaced from a longitudinal axis of the extractor and lying on opposing sides of the longitudinal axis of the extractor, wherein relative movement of the lead and extractor causes pivoting of the first and second clamping members. 
     The extractor can include a carrier for moving the first clamping member, the carrier including an engagement tab to engage a slot in a housing containing the cutter, wherein movement of the carrier concurrently causes pivoting of the first clamping and rotation of the housing to rotate the cutter. 
     In accordance with another aspect, the present invention provides an extractor for removing an implanted lead from a patient, the extractor having a lumen to receive the lead and first and second clamping members, the clamping members movable between unclamped positions where the lead can freely move within the lumen and clamped positions to frictionally engage the lead, wherein relative movement of the extractor and lead effects pivotable movement of the clamping members. 
     In some embodiments, further relative movement of the extractor and lead causes further frictional force by the first clamping member on the lead. In some embodiments, the first clamping member has a first hinge and the second clamping has a second hinge, the first and second hinges radially spaced from a longitudinal axis of the extractor and lying on opposing sides of the longitudinal axis of the extractor. 
     The extractor can include a movement mechanism for axially moving the first clamping member, wherein such axial movement rotates a cutter of the extractor. 
     The first and second clamping members can in some embodiments be spring biased to the clamped positions. 
     In some embodiments, relative movement of the extractor and lead occurs in discrete increments which progressively swallow the lead within the lumen of the extractor. 
     In accordance with another aspect of the present invention, a method of removing an implanted lead from a patient is provided comprising:
         a) providing an extractor having a lumen to receive the lead and a cutter at a distal portion;   b) positioning the extractor so the lead extends through the lumen of the extractor and the cutter is adjacent or in contact with the tissue adjacent the lead;   c) moving a first clamping member of the extractor in a first direction to relatively move the extractor and lead to swallow the lead; and   d) cutting tissue adjacent the lead by the cutter.       

     In some embodiments, the step of cutting tissue includes rotating the cutter. In some embodiments, rotation of the cutter occurs concurrently with movement of the first clamping member. 
     The method can further include the steps of moving a second clamping member to clamp the lead, and the unclamping the first clamping member before the step of moving the second clamp member proximally and unclamping the second clamping member before the step of moving the first clamping member to thereby provide incremental relative movement of the lead and extractor. The method can further comprise the step of moving a second clamping member proximally to swallow the lead. 
     In some embodiments, the first clamping member is released after the second clamping member is moved to clamp the lead, and the second clamping member is released after the first clamping member is moved to clamp the lead. 
     In some embodiments, the step of moving the first clamping member includes the step of tilting the first clamping member with respect to a longitudinal axis of the extractor so it moves from a first angle to a second different angle. 
     In some embodiments, the extractor has a second clamping member, and the first and second clamping members each have an opening to receive the lead therethrough and changing angles of the first and second clamping members with respect to a longitudinal axis of the extractor changes the angle of the first and second openings to clamp the lead. 
     The method may further include the step of rotating a flexible sheath to rotate the lead to unscrew a distal end of the lead from tissue. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred embodiment(s) of the present disclosure are described herein with reference to the drawings wherein: 
         FIG.  1    illustrates a patient&#39;s anatomy showing an implanted cardiac lead to be removed; 
         FIG.  2    is a perspective view of one embodiment of the lead extractor of the present disclosure; 
         FIG.  3    is a perspective view of the lead extractor of  FIG.  2    positioned over the cardiac lead; 
         FIG.  4    is a side view of the lead extractor of  FIG.  2    with the outer housing shown in phantom to illustrate the internal rings and springs, the extractor shown in the neutral position; 
         FIG.  5    is a side perspective view similar to  FIG.  4    with the housing removed for clarity; 
         FIG.  6    is a side view of the lead extractor of  FIG.  2    showing the distal clamp ring moved to the angled position; 
         FIG.  7    is a side view similar to  FIG.  6    showing the proximal clamp ring moved to the angled position; 
         FIG.  8    is a close up view a portion of the cutter (knife) of the housing for cutting tissue; 
         FIG.  9    is a close up view of the distal end of the housing of  FIG.  2   ; 
         FIG.  10    is a front view illustrating the cable extending through the notch in the proximal clamp ring; 
         FIGS.  11 A- 11 C  are schematic views of an embodiment utilizing a motor to move (oscillate) the cables of the lead extractor to alternatively angle and retract the distal and proximal clamping rings; 
         FIGS.  12 A- 12 F  illustrate side views (with the housing shown in phantom) to show the method of use of the lead extractor of  FIG.  2    wherein: 
         FIG.  12 A  illustrates the lead extractor in the neutral position with the proximal and distal clamp rings in the substantially perpendicular position; 
         FIG.  12 B  illustrates a first cable pulled proximally to move the distal clamp ring to the angled position; 
         FIG.  12 C  illustrates the first cable pulled further proximally to move the lead proximally; 
         FIG.  12 D  illustrates a second cable pulled proximally to move the proximal clamp ring to the angled position; 
         FIG.  12 E  illustrates the first cable released to return the distal clamp ring to its substantially perpendicular and distal position; 
         FIG.  12 F  illustrates the second cable pulled further proximally to move the lead further proximally; 
         FIGS.  13 A- 13 D  are side views of the lead extractor of  FIG.  2   , with the internal rings and spring shown in phantom, illustrating how the lead and extractor are relatively moved to cut tissue about the lead wherein: 
         FIG.  13 A  illustrates the lead extractor being inserted over an implanted lead to approach the tissue surrounding the lead, the lead extractor shown in the neutral position with the proximal and distal clamp rings in the substantially perpendicular position; 
         FIG.  13 B  illustrates the first cable pulled proximally to move the lead proximally and sever the surrounding tissue; 
         FIG.  13 C  illustrates a second cable pulled proximally to move the proximal clamp ring to the angled position; 
         FIG.  13 D  illustrates the first cable released to return the distal clamp ring to its substantially perpendicular position and the second cable pulled further proximally to move the lead further proximally with the surrounding tissue being severed; 
         FIG.  14    is a perspective view of an alternative embodiment utilizing a manual control to actuate the cables of the extractor of  FIG.  2   ; 
         FIG.  15    is a perspective view of an alternate embodiment of the lead extractor of the present disclosure having a flexible tube; 
         FIG.  16    is a close up perspective view of the area of detail of  FIG.  15   ; 
         FIG.  17    illustrates a perspective view of another alternate embodiment of the lead extractor, 
         FIGS.  18 A- 18 D  are side views of the lead extractor of  FIG.  17   , with the sheath shown in cross-section, illustrating how the lead and extractor are relatively moved to cut tissue about the lead wherein: 
         FIG.  18 A  illustrates the lead extractor being inserted over an implanted lead to approach the tissue surrounding the lead, the lead extractor shown in the neutral position with the proximal and distal clamp rings in the substantially perpendicular position; 
         FIG.  18 B  illustrates the first cable pulled proximally to move the lead proximally and sever the surrounding tissue; 
         FIG.  18 C  illustrates a second cable pulled proximally to move the proximal clamp ring to the angled position; and 
         FIG.  18 D  illustrates the first cable released to return the distal clamp ring to its substantially perpendicular position and the second cable pulled further proximally to move the lead further proximally with the surrounding tissue being severed. 
         FIG.  19    is a perspective view of an alternate embodiment of the lead extractor of the present disclosure shown positioned over a cardiac lead; 
         FIG.  20    is a perspective view of the outer housing of the lead extractor of  FIG.  19   ; 
         FIG.  21    is a perspective view of the inner housing of the lead extractor of  FIG.  19   ; 
         FIG.  22    is an exploded perspective view of the lead extractor of  FIG.  19   ; 
         FIG.  23    is a perspective view of the outer housing of the lead extractor of  FIG.  19   ; 
         FIG.  24    is a cross-sectional view of the outer housing of  FIG.  23   ; 
         FIG.  25    is a cross-sectional view illustrating the lead extractor in the initial position and showing the lead extending through the extractor; 
         FIG.  26    is a cross-sectional view similar to  FIG.  25    illustrating the carrier of the lead extractor moved to the proximal position; 
         FIG.  27    is a cross-sectional view similar to  FIG.  26    illustrating the carrier of the lead extractor starting to be returned to the initial distal position; 
         FIG.  28    is a cross-sectional view similar to  FIG.  27    illustrating the carrier of the lead extractor moved to the distal position; 
         FIG.  29    is a cross-sectional view similar to  FIG.  28    illustrating the carrier and components of the lead extractor in the initial position; 
         FIG.  30    is a perspective view corresponding to the position of  FIG.  25   , the inner and outer housings removed for clarity, and showing the lead extending through the extractor; 
         FIG.  31    is a perspective view corresponding to the position of  FIG.  26   , the inner and outer housings removed for clarity; 
         FIG.  32    is a perspective view corresponding to the position of  FIG.  27   , the inner and outer housings removed for clarity; 
         FIG.  33    is a perspective view corresponding to the position of  FIG.  28   , the inner and outer housings removed for clarity; 
         FIG.  34    is a perspective view corresponding to the position of  FIG.  29   , the inner and outer housings removed for clarity; 
         FIG.  35    is a front view of the lead extractor of  FIG.  19   ; 
         FIG.  36    is a front view similar to  FIG.  35    showing rotation of the outer housing with respect to the inner housing for cutting tissue; 
         FIG.  37    is a side view of an alternate embodiment of the lead extractor of the present disclosure having a flexible sheath thereover, the sheath shown in cross-section; 
         FIG.  38    is a side view similar to  FIG.  37    showing rotation of the flexible sheath to rotate the extractor and lead; 
         FIG.  39    is a side view similar to  FIG.  38    showing freeing of the distal tip of the lead from the tissue as a result of rotation of the sheath; 
         FIG.  40    is a side view similar to  FIG.  39    showing removal of the flexible sheath, lead extractor and lead from the body; 
         FIG.  41    is a perspective view of the actuator in a first (neutral) position; 
         FIG.  42    is a perspective view of the actuator in a second position to pull the cable proximally to retract the carrier of the lead extractor; 
         FIG.  43    is a perspective view of the actuator in an override position to advance the carrier of the electrode lead to the distal clamp release position; and 
         FIG.  44    is a cross-sectional view illustrating the lead extractor in the override position to release the clamping rings. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     The lead extractor disclosed herein advantageously holds the lead adjacent the area where the tissue cutting (severing and/or dissecting) occurs, thereby transferring the power of the work required to the location where it is needed. This provides an advantage over prior lead extractors where the extractor is held and maneuvered from a proximal end to apply a cutting or dissecting force to the tissue at the remote distal end. Thus, the lead extractor of the present invention provides for lead removal with minimal damage to the patient&#39;s tissue. 
     To this end, the present disclosure provides a lead extracting device which grips and frictionally retains the lead, and then incrementally moves relative to the lead, cutting the surrounding tissue as it is moved proximally within the device. Note the lead and extractor move relative to each other. That is, if the distal end of the lead is fixed, the relative movement will occur by the extractor being advanced along the lead. If the distal end of the lead is not fixed, relative movement will occur by the lead moving proximally within the extractor. Also, relative movement can include proximal movement of the lead simultaneous with distal movement of the extractor. In any case, as a result of this relative movement, the extractor “swallows” the lead within its lumen as it incrementally and progressively cuts through tissue around the lead to free the lead from the tissue. Cutting of tissue can occur by severing and/or dissecting tissue. The cutter is shown as part of the housing in the embodiments herein, however, alternatively the cutter can be a separate component attached to the housing. 
     With reference to  FIGS.  2 ,  4  and  5   , the lead extracting device is designated generally by reference numeral  10  and includes an outer housing or body  14  and an internal tubular member or inner body  12  having a lumen dimensioned to receive a lead therein. The outer housing (outer tube)  14  has a proximal end  20  and a distal end  30 . As used herein the term “proximal” refers to the portion that is closer to the user and the term “distal” refers to the portion that is further from the user. A cutting knife (cutter) or cutting portion  50  is positioned at the distal end  30  of outer housing  14  configured to cut tissue surrounding the lead, designated by reference letter “A”.  FIG.  1    illustrates an anatomical view of the heart, illustrating the location of the cardiac lead A which is desired to be removed from the right ventricle B. It should be appreciated that the devices disclosed herein are described for removing a cardiac lead, however, it should be understood that the device also has other surgical applications. Note tissue ingrowth around the lead also occurs at regions along the length of the lead proximal of the distal tip of the lead. 
     The lead extractor includes a distal clamping ring  22 , a proximal clamping ring  24 , a distal fixed ring  26  and a proximal fixed ring  28 . A first actuator or actuating (movement) mechanism in the form of a first wire or cable  32  is operably connected to the distal clamping ring  22  and a second actuator or actuating mechanism in the form of a second wire or cable  34  is operably connected to the proximal clamp ring  24 . The cable  32  is operable to pivot distal clamping ring  22  from a substantially perpendicular position to an angled position with respect to the longitudinal axis of the extractor  10 . In the substantially perpendicular position, the extracting device  10  is freely movable over the lead A. In the angled (tilted) or oblique position, due to the dimension of the opening in the distal clamping ring  22 , the distal clamping ring  22  frictionally engages, i.e., clamps, the external surface of the lead A as the surface around the opening in the clamping ring  22  frictionally engages the outer surface of the lead. Such clamping allows relative movement of the lead, i.e., “swallowing” of the lead described in detail below. Similarly, the cable  34  is operable to pivot proximal clamp ring  24  from a substantially perpendicular position to an angled position with respect to the extractor  10 . In the substantially perpendicular position, the extracting device  10  is freely movable over the lead A. In the angled (tilted) or oblique position, due to the dimension of the opening in the proximal clamping ring  24 , the proximal clamping ring  24  frictionally engages, i.e., clamps, the external surface of the lead A as the surface around the opening in the clamping ring  24  frictionally engages the outer surface of the lead. Such clamping allows relative movement of the lead, i.e., “swallowing” of the lead as described in detail below. A distal spring  36  is positioned around tubular member  12  to bias the distal clamp ring  22  in a distal direction and a proximal spring  38  is positioned around tubular member  12  to bias the proximal clamp ring  24  in the distal direction. 
     First cable  32 , also referred to herein as the distal ring cable, is fixedly attached to distal ring  22  (at connection  33 ), extends through an aperture  42  in the distal fixed ring  26  and an aperture  44  in proximal fixed ring  28 . Proximal clamp ring  24  has a cutout or notch  27  to accommodate the first cable  32  (see also  FIG.  10   ). The cable  32  extends proximally to a position outside the patient for manipulation manually by a user or alternatively for connection to a motor as described below. 
     Cable  34 , also referred to herein as the proximal ring cable, is fixedly attached to proximal ring  24  (at connection  35 ) and extends through an aperture  46  in the proximal fixed ring  26 . The cable  34  extends proximally to a position outside the patient for manipulation manually by a user or alternatively for connection to a motor. The cables  32  and  34  thereby provide a movement mechanism for the clamping members. 
     The extractor  10  preferably has three operable positions. In a first or initial position, referred to as the neutral or zero position, both the distal and proximal clamping rings  22 ,  24  are in the substantially perpendicular position in which they do not frictionally retain the cardiac lead and therefore the device  10  can be slidably moved over the lead A, as the lead A extends through the lumen of the tubular member  12 . In this neutral position, this sliding movement is obtained since the inside diameter of the opening in the distal ring and the inside diameter of the opening in the proximal ring  22  is greater, e.g., slightly greater, than the outside diameter D of the lead A. Note this neutral position also enables the device  10  at any time during the procedure to release the lead and be adjusted or removed from the lead and patient. In the second position, the distal ring  22  is moved to the angled position to engage (clamp) the lead A while the proximal ring  24  remains in the substantially perpendicular position, as shown in  FIG.  6   . In the third position, the proximal ring  24  is moved to the angled position to engage (clamp) the lead A while the distal ring  22  remains in the substantially perpendicular position, as shown in  FIG.  7   . It should be appreciated that alternatively, the second position can denote when the proximal ring  22  is moved to the angled position to engage the lead A and the distal ring  24  remains in the substantially perpendicular position, in which case the third position would denote the position wherein the distal ring  22  is moved to the angled position to engage the lead A while the proximal ring  24  remains in the substantially perpendicular position. 
     The knife (cutter)  50  preferably has an angled cutting edge that avoids the knife cutting into the vessel wall. The cutting edge is beveled at end  52 , and has a small cutting edge  54  ( FIG.  8   ), extending at an opposite angle to the bevel, thereby preventing the knife  50  from going into the lead. The knife  50  has a circular design with a sinuous shape, thereby providing a curved knife to perform a relative movement from the cutting edge to the tissue as in a guillotine-like action. The angles shown in  FIG.  8    are by way of example as other angles are also contemplated. The inner diameter E of the knife  50  ( FIG.  9   ) preferably is slightly greater than the outer diameter of the lead A to be received in the lumen of device  10 . 
     Turning now to the method of use, and with reference to  FIGS.  12 A- 12 F , the device  10  is inserted over the lead A and advanced over the lead A until the knife  50  at the distal end  30  of the tubular member  12  is at the desired site, namely the site where the lead A is embedded or surrounded by tissue so it cannot be removed. This is typically proximal of the distal tip of the lead. In this position, the device  10  is ready for lead extraction. 
     The user than pulls cable  32  proximally, or if motor operated, turns on the motor which automatically pulls the cable  32  proximally. In the first proximal movement of the cable  32 , the distal clamping ring  22  is pivoted to its angled position of  FIG.  12 B  to frictionally clamp or grasp the lead A. Upon further movement of the cable  32 , the lead A is pulled back due to its frictional engagement with the device  10  via distal clamp ring  22  as shown in  FIG.  12 C  and/or the device  10  is moved over the lead in this relative movement to “swallow” the lead A. (Since the proximal ring  24  is in its substantially perpendicular or non-engaging position, the lead can move through the opening in the ring  24 ). As the lead A is moved back proximally in the direction of the arrow of  FIG.  12 C  it begins to be freed from tissue as the surrounding tissue is engaged and cut (severed and/or dissected) by knife  50 . As can be appreciated, the cutting of tissue occurs adjacent the end of the device where the lead is engaged, thus providing more leverage and easier severing of the tissue. As the distal ring  22  is pulled proximally (rearwardly), it compresses distal spring  36 . In an exemplary embodiment, distal clamping ring  22  is pulled back a maximum of approximately halfway to the distal fixed ring  26 . In an exemplary embodiment, the distance between distal clamping ring  22  and distal fixed ring  26  is about 20 mm and the distal clamping ring  22  is pulled proximally about 10 mm thereby moving the lead A proximally about 10 mm in the direction of the arrow of  FIG.  12 C . Other distances are also contemplated. 
     Once the distal clamping ring  22  has been pulled back to relatively move the lead A proximally or “swallow” the lead a predetermined amount, the second cable  34  can now be actuated. The user pulls cable  34  proximally, or if motor operated, the motor automatically pulls the cable  34  proximally after the first cable  32  has been pulled. In the first proximal movement of the cable  34 , the proximal clamping ring  24  is pivoted to its angled position of  FIG.  12 D  to frictionally clamp or grasp the lead A. Once the cable  34  has moved the proximal ring  32  to its angled position, the tension on the first cable  34  is released so the distal ring  22  can return to its substantially perpendicular or non-engaged position, aided by the force of distal spring  36  ( FIG.  12 E ). In a preferred embodiment, the first cable  32  (and thus the distal clamp ring  22 ) is not released until the second cable  34  has been tensioned to move the proximal ring  24  to engage the lead A. This helps prevent slippage, e.g., distal movement of the lead A, since the lead A is continuously being grasped, albeit by alternating the grasping function between the proximal and distal clamping rings  22 ,  24 . 
     After the cable  34  has been pulled to pivot the proximal clamping ring  24  to its angled position, further retraction of the cable  34  pulls the lead A back (proximally) or moves the device  10  distally due to its frictional engagement with the device  10  via distal clamp ring  24 . Thus, the lead A is relatively moved further back proximally in the direction of the arrow to further free it from surrounding tissue as the tissue is cut by knife  50  as shown in  FIG.  12 F . As the proximal ring  22  is pulled proximally (rearwardly), it compresses proximal spring  38 . In an exemplary embodiment, proximal ring  22  is pulled back a maximum of approximately halfway to the proximal fixed ring  28 . In an exemplary embodiment, the distance between proximal clamp ring  24  and proximal fixed ring  28  is about 20 mm and the proximal clamp ring  24  is pulled proximally about 10 mm, thereby relatively moving the lead A about 10 mm. Other distances are also contemplated. 
     Next, the first cable  32  is pulled to once again pivot the distal ring  22  to the angled engaging position. Once pulled, the second cable  34  can now be released, followed by further retraction of the first cable  32 , to move the lead proximally due to its frictional engagement. After such movement, the second cable  34  is pulled proximally, followed by release of the first cable  34 , and then further pulling of the cable  34  to move the lead A still further proximally and to continuously sever the surrounding tissue by knife  50 . This step of alternatively pulling of the cables  32 ,  34  is repeated until the lead A is freed from the tissue and can be removed (with or separately from the device  10 ) from the tissue. This alternating cable motion can also be referred to as an oscillating movement in that the pulling of the cable alternates between the first and second cables, to incrementally pull the lead proximally or advance the extractor distally. This alternating action can also be considered as a step by step progressive “swallowing” of the lead. It can also be considered a tunneling action as it tunnels through tissue to separate tissue from the lead. 
       FIGS.  13 A- 13 D  illustrate how the lead is pulled back relative to tissue T.  FIG.  13 A  shows the lead extractor being inserted over lead A to the position where the lead is captured by tissue T. After positioning of the extractor  10  in the desired position, the first cable  32  is pulled rearwardly and the lead A is retracted or the device  10  advanced as described above, with the tissue T engaging the cutting edge of knife  50  to cut the tissue surrounding the lead A to thereby free the lead (see  FIG.  13 B ). In  FIG.  13 C , the proximal clamp ring  24  is angled by the pulling of the second cable  34 . The first cable  32  is then released, and the proximal cable  34  is pulled back further to further move the lead proximally or advance the device  10 , thereby causing the tissue to again be into contact with the knife  50  to cut the tissue. As explained herein, this keeps being repeated so that the knife  50  can continue to cut the tissue as the lead A is incrementally and progressively pulled rearwardly or swallowed within the lumen of tube  12  of the lead extractor  10 . 
     In one embodiment, this alternating movement can be achieved by handle mechanism  80  shown in  FIG.  14   . The handle mechanism  80  includes a first actuator  82 , illustratively in the form of a pivotable handle with a finger loop  83 , and a second actuator  84 , also illustratively in the form of a pivotable handle with a finger loop  85 . The first actuator  82  is operatively connected to the first cable  32  such that proximal movement of the actuator  82 , e.g., moving of the finger loop  83  toward stationary handle  86 , pulls the cable  32  proximally and distal movement returns the cable  32  to its original position. Similarly, second actuator  84  is operatively connected to the second cable  34  such that proximal movement of the actuator  84  (away from the stationary handle  86 ) pulls the cable  34  proximally and distal movement returns the cable  34  to its original position. The handle mechanism  80  in a preferred embodiment includes a locking mechanism (not shown) to ensure that either cable  32 ,  34  cannot be released until the other cable has been moved proximally to move its respective clamping ring to the angled clamping position to frictionally engage the lead. A rotation knob  88  can be provided to rotate the lead extractor to thereby rotate the clamped lead if desired. 
     As can be appreciated, the pistol grip and pivotable handles are shown by way of example as other handle configurations and other types of actuators, e.g., sliding tabs, are also contemplated to provide manual control of the cable movement. 
     In an alternate embodiment, an external power source such as a motor assembly is provided to electrically drive (actuate) the cables instead of the manual operation by the user. As shown schematically in  FIG.  11 A , motor rotation of the wheel  90 , which is preferably eccentric, from the neutral position of  FIG.  11 A  to the position of  FIG.  11 B , pulls cable  32  proximally to move the distal clamping ring  22  to the angled position and then to pull the distal clamping ring  22  proximally to retract or swallow the clamped lead as described above. Rotation of the wheel in the opposite direction ( FIG.  11 C ) will cause cable  34  to be pulled proximally to move the proximal clamping ring  24  to the angled position and to pull the proximal clamping ring  24  proximally to retract the clamped lead further proximally or further swallow lead. Thus, as can be appreciated, the motor causes the oscillating motion of the wheel and respective cables to incrementally relatively retract the lead. It should be appreciated that the motor controlled embodiment can be configured so that the clamping ring cannot be released from its angled position until the other clamping ring is moved to its angled clamping position as described above. Note that such motor operated cables can be utilized with the other embodiments disclosed herein, e.g., extractor  200  discussed below. 
       FIGS.  15 - 18    illustrate an alternate embodiment of the lead extractor, designated generally by reference numeral  100 . The lead extractor  100  is identical to the lead extractor  10  of  FIG.  2    except for provision of the flexible tube/sheath. Therefore, the identical components have been labeled with corresponding numbers in the “100 series” so that extractor  100  has a knife (cutter)  150 , distal clamping ring  122 , a proximal clamping ring  124 , a distal fixed ring  126 , a proximal fixed ring  128 , a first cable  132  operably connected to the distal clamp ring  122  and a second cable  134  operably connected to the proximal clamp ring  124 . The cable  132  is operable to pivot distal clamping ring  122  from a substantially perpendicular position to an angled position and the cable  134  is operable to pivot proximal clamping ring  124  from a substantially perpendicular position to an angled position. As in the embodiment of  FIG.  2   , a distal spring  136  is positioned around tubular member  112  to bias the distal clamping ring  122  in a distal direction and a proximal spring  138  is positioned around tubular member  112  to bias the proximal clamping ring  34  in the distal direction. 
     The extractor  100  differs from extractor  10  in that a flexible tube (sheath)  160  having a handle  162  is provided. The handle  162  enables the extractor  100  to be rotated to thereby rotate the clamped lead. Such rotation provides an unscrewing action of the lead if the user deems it desirable. Thus, after the extractor  100  cuts the tissue surrounding the lead, the user can keep the extractor  100  locked to hold the lead, and the sheath can be rotated to facilitate removal of the embedded screwed-in tip of the lead. Note the tube  160  has a plurality of cutouts in the wall to provide the desired flexibility. The housing  114  can also have a plurality of cutouts in the wall to provide the desired flexibility. In the alternate embodiment of  FIG.  17   , a sheath  170  is provided to cover the flexible tube  160 . 
       FIGS.  18 A- 18 D  illustrate the use of extractor  100  which is identical to the use described in conjunction with  FIGS.  13 A- 13 D  except for provision of a flexible sheath  170  in which the housing  114  is positioned. Thus, as can be appreciated the movement of the clamping rings  122  and  124 , and relative movement of the extractor  10  and the lead A shown in  FIGS.  18 A- 18 D  are identical to that of  FIGS.  13 A- 13 D  and for brevity are not repeated herein. 
     Although two clamping rings are described in the embodiments herein, it is also contemplated that a single clamping ring or more than one clamping ring can be utilized. 
     An alternate embodiment of the lead extractor of the present invention is illustrated in  FIGS.  19 - 36   . The lead extractor is designated generally by reference numeral  200  and includes an outer body (outer housing)  202  and an inner body (inner housing)  204 . The lead extractor  200  is similar to lead extractor  10  described above in that it is configured to move relative to the lead to “swallow” the lead in increments. However, in the lead extractor  10  of  FIG.  2   , the user manipulates the actuators to selectively control pivoting of the clamping members, alternately clamping and releasing the distal and proximal clamping members. In the lead extractor  200  of  FIG.  19   , the changed orientation of the clamping members is a result of the relative movement of the lead extractor  200  and lead. Additionally, the lead extractor  200  has an enhanced cutting action as the cutter also rotates. Other differences between extractor  200  and extractor  10  will become apparent from the detailed description below of extractor  200 . 
     Turning to the components of lead extractor  200 , and with reference to  FIGS.  20 - 24   , outer body (or outer tube)  202  of lead extractor  200  has a proximal portion  206 , a distal portion  208  and an intermediate portion  207  therebetween. A cutter or cutting portion  210  is formed at the distal portion  208  and preferably includes a serrated edge or toothed edge to effectively cut tissue adjacent the lead. Outer body  202  is positioned coaxially over inner housing (or inner tube)  204  as the inner housing  204  is received in lumen  216  of outer body  202 . Outer body  202  has an internal helical slot  218  and is rotatable relative to inner housing  204  (see  FIGS.  35  and  36   ) to cut (sever and/or dissect) tissue as described in more detail below. Outer housing  202  has a conical tip  202   a  tapering in a distal direction to facilitate tunneling of the device. Radial slots  212 ,  214  receive disc  231  and another disc (not shown) or bars which are welded to the outer tube  202  to keep the device  200  together. Also, these block axial movement of the outer body  202  so that when the carrier  240  moves axially, since axial movement of the outer body  202  is blocked, it is forced to rotate. 
     With reference to  FIGS.  21 - 22   , the inner housing  204  has a proximal portion  220 , a distal portion  222  and an intermediate portion  226  between the proximal portion  220  and distal portion  222 . A cutter or cutting portion  224 , preferably having a serrated or toothed edge as shown, interacts with the cutting portion  210  of outer housing  202  to sever tissue adjacent the lead. That is, the cutting portion  210  of outer housing  202  overlies a counterpart cutting portion  224  of inner housing  204 . A circumferential slot  230  is formed between ring  234  and distal end  232  of the carrier receiving portion to receive semicircular disc  231 . 
     Inner housing  204  has a pair of proximally extending arms  238  to form a gap to slidably receive carrier or vehicle  240 . Movement of carrier  240  effects relative movement of the extractor  200  and lead. A proximal end cap  249  is secured within top and bottom notches  238   a  of arms  238  to secure the arms  238  and provide a back wall enclosure for the inner housing  204 . Carrier  240  is slidably mounted within inner housing  204  for movement between proximal (retracted) and distal positions, proximal defined as noted above as the region closer to the user and distal as the region further from the user (and closer to the tip of the lead). The movement of carrier  240  provides the desired clamping of the lead which is positioned within the lumen  228  of inner housing  204 . A cable  330  described in detail below effects movement of the carrier  240 . 
     Carrier  240  is formed by proximal fixed support ring  242 , distal fixed support ring  250 , upper support  274  and lower support  280 . The terms “upper” and “lower” as used herein refer to the orientation of the device in the orientation shown in the drawings and are used herein for ease of description. Clearly, if the orientation of the device changes, the references “upper” and “lower” will also accordingly change. Contained within carrier  240  is proximal clamping ring  260  which has a hinge point on its lower surface and is biased by proximal spring  266  to a tilted position (with respect to the longitudinal axis of the extractor  200  and lead) as shown in  FIGS.  21  and  25   . In this tilted position (tilted toward the distal end of the device), the proximal clamping ring  260  provides a clamping force on the lead as its central opening  264  is sufficiently angled with respect to the outer surface of the lead so the surface surrounding opening  264  grasps (clamps) the lead. Upper support  274  has a distal notch  278   a  seated within upper notch  252  of distal fixed support ring  250  and a proximal notch  278   b  seated within upper notch  244  of proximal fixed support ring  242  to retain and secure these components. Similarly, lower support  280  has a distal notch  284   a  seated within lower notch  254  of distal fixed support ring  250  and a proximal notch  284   b  seated within lower notch  246  of proximal fixed support ring  242  to retain and secure these components. Upper tabs  276   a ,  276   b  of upper support  274  and lower tabs  282   a ,  282   b  of lower support  280  interact with the helical slot  218  formed in the outer housing  202  described in more detail below. Proximal clamping ring  260  receives elongated portion  274   a  of upper support  274  in upper slot  262 . A similar slot on the opposing (bottom) side of proximal clamping ring  260  receives lower support  280 . A slot  268  of proximal spring  266  accommodates upper support  274 . Spring  266  is hinged at a bottom portion and has an opening  270  through which the lead can extend. Spring  266  is preferably attached to proximal clamping ring  260 . 
     Distal of carrier  240 , positioned within inner housing  202  between arms  238 , is a distal clamping ring  290  which has a hinge point on the top surface and is biased by distal spring  302  to the tilted position as shown in  FIGS.  21  and  25   . Spring  302  is preferably attached to distal clamping ring  290  and hinged at a top portion. As can be appreciated, the distal clamping ring  290  and proximal clamping ring  260  have hinge points on opposing sides of the longitudinal axis of the device  10 . In the tilted position of  FIG.  21   , (tilted toward the proximal end of the device), the distal clamping ring opening  290  is at a sufficient angle with respect to the lead such that the lead is clamped by the ring  290 . A ridged, toothed or irregular surface  295  is formed around part or alternatively the entire circumference of opening  292  in distal clamping ring  290  to enhance clamping of the lead extending therethrough when the distal clamping ring  290  is in the tilted position. Such ridged, toothed or irregular surface can also be provided around part or the entire circumference of the opening  264  of proximal clamping ring  260  to enhance clamping of the lead. 
     Clamp engaging member  308  has a distal tab  314  and proximal tab  312 . Clamp engaging member  310  similarly has a distal tab  320  and a proximal tab  318 . The clamp engaging members  308 ,  310  are seated within side notches  294 ,  296 , respectively, of distal clamping ring  290 . The tabs  314 ,  312 ,  318 , and  320  support and retain the upper end of the distal clamping ring  290 . 
     Cable  330  ( FIG.  25   ) includes an outer cable  331  which is attached to the end cap  249  of inner housing  204 . Coaxially positioned within the outer cable  331  is inner cable  333  which extends distally from outer cable  331  and is attached to the fixed proximal ring  242  of carrier  240 . Cable  333  provides a movement mechanism as proximal movement of inner cable  333  pulls the carrier  240  in a proximal direction and distal movement of the inner cable  333  pushes the carrier  240  in a distal direction. The cable  333  is actuated by a trigger  340  shown in  FIG.  41    and described in conjunction with the method of use. 
     The use of the extractor  200  will now be described for use to extract an implanted cardiac lead, it being understood it can be used to extract other leads or other components/devices. Oftentimes, tissue ingrowth and plaque builds around the lead over a period of time which makes extraction difficult. The extractor  200  functions to extract the lead by application of the force at the distal end. That is, the lead extractor  200  is advanced in steps (increments) relative to the lead, thereby cutting e.g., severing and/or dissecting, tissue about the lead and tunneling around the lead to cut it away from tissue. When the tissue has been cut away, the lead can be extracted from the heart tissue. The extractor  200  and lead A are relatively movable with respect to each other. Therefore, if the lead is fixed, then the extractor  200  will move progressively (in discrete increments) over the lead; if the lead is not fixed, then the extractor will progressively pull the lead (in discrete increments) back into the extractor  200 . Alternatively, both the extractor and lead can move in opposing directions. In any event, this relative movement causes the “swallowing” of the lead by the extractor  200 . 
       FIGS.  25 - 29    show in cross-sectional views operation of the extractor  200 .  FIGS.  30 - 34    are perspective views corresponding to the respective positions of  FIGS.  24 - 29   , however the inner housing  204  and outer housing  202  have been removed for clarity. 
     In use, the device  200  is inserted over a proximal end of the lead, e.g., a cardiac lead, which is embedded in tissue and desired to be removed. The extractor  200  is advanced until the distal end  208  of the outer housing  202  encounters hard tissue. Note, in the insertion position, the proximal clamping ring  260  is tilted toward the distal end and the distal clamping ring  290  is tilted toward the proximal end as shown in  FIGS.  25  and  30   . In this position, the extractor  200  can be forced over the lead A with the openings  292  and  264  of distal and proximal clamping rings  290 ,  260  providing a sufficient gap (upon such force being applied) for passage of the outer diameter of the lead and not providing a sufficient clamping or frictional force on the lead A to prevent such passage. In this initial position for insertion over the lead, springs  266  and  302  are not compressed and bias the clamping rings  260 ,  290 , respectively in the tilted positions shown. Note the clamping rings  260 ,  290  can optionally be moved to a less tilted position by movement to the override position described below for initial insertion of the lead, however, in this embodiment it is not necessary since the extractor  200  can be forced over the lead. 
     When hard tissue, e.g., plaque, is encountered so that the extractor  200  cannot be further advanced sufficiently easy over the lead, the user actuates trigger  340  ( FIG.  42   ) to thereby pull inner cable  333  proximally, which pulls the carrier  240  proximally since cable  331  is attached to the fixed proximal ring  242 . When the carrier  240  is pulled back, shown by the proximally pointing arrows of  FIG.  26   , the extractor  200  is advanced distally over the lead A as proximal clamping ring  260  clamps lead A. Note the more relative movement of carrier  240  and lead A, the more tilting of the proximal clamping ring  260  and more clamping force applied to the lead A. Simultaneous with such proximal movement of the carrier, the outer housing  202  rotates, preferably about 45 degrees although other degrees of rotation are also contemplated, due to the engagement of tabs  276   a ,  276   b  (of upper support  274 ) and the engagement of tabs  282   a ,  282   b  (of lower support  280 ) with the internal helical slot  218  of outer housing  202 . This axial and rotational movement of outer housing  202 , in cooperation with the stationary (non-rotating) cutting portion  224  of inner housing  204 , facilitates the cutting portions cutting through tissue around the lead A. This retracted position of carrier  240  is also shown in  FIG.  31   . Note as the carrier  240  is retracted, distal clamp ring  290  is pivoted about upper hinge point in a clockwise direction, compressing spring  302 . The relative movement of the extractor  200  and lead A causes the distal clamping ring  290  to move to this less angled position of  FIG.  26    to facilitate movement of the extractor  200  as the opening in the distal clamping ring  290  provides a larger diameter with respect to the outer diameter of the lead A and no longer provides a restrictive clamping force on the lead A. Although the angle of the proximal clamping member  260  might not substantially change during such retraction of carrier  240 , remaining in substantially the same position as in  FIG.  25   , biased by spring  266 , it will tilt more if needed such as if a larger force is applied. 
     Next, the trigger  252  is returned to the neutral position ( FIG.  41   ), thereby pushing cable  331  distally, which pushes the carrier  240  distally in the direction of the arrow of  FIG.  27    to reset the extractor  200  for the next incremental movement. As shown in  FIGS.  27  and  31   , in the initial movement of the carrier  240  distally, the interaction with the lead A pivots the proximal clamping ring  260  about its bottom hinge in a counterclockwise direction to a more vertical position, thereby compressing spring  266 , and creating a larger diameter gap about opening  264  with respect to the outer diameter of the lead A to facilitate movement of the extractor  200  with respect to the lead A. The carrier  240  thereby moves to the distal position of  FIGS.  28  and  33   , with proximal clamping ring  260  remaining in the less tilted (and unclamped) position as a result of such movement. Distal clamping member  290  returns to the tilted position of  FIG.  25    as the extractor  200  is moved relative to lead A and it remains in the tilted clamping position to clamp the lead A and prevent the lead shifting back, i.e., reversing itself. Such distal movement of carrier  240  causes the outer housing  202  to rotate during its axial advancement due to the tab/helical slot  218  engagement discussed above, the axial movement and rotation of the cutter (rotating relative to the fixed cutting portion of inner housing  204 ) cutting tissue around the lead A. Note the clamping member  290  prevents the lead from moving back and there is no (or little) relative movement of the lead and extractor  200 . However, the outer housing  202  will still rotate upon movement of the carrier  240 , thus making the same but opposite cutting movement when the carrier  240  is moved distally. 
     After full distal travel of the carrier  240  with respect to the lead A, the carrier  240  returns to the position of  FIGS.  29  and  34   , which is the same position of  FIGS.  25  and  30   . Note that the relative movement of the extractor  200  and the lead A causes automatic tilting of the clamping rings  260  and  290 . That is, due to the angular positioning of the clamping rings  290 ,  260 , and the top and bottom hinge points, they operate as follows: when the carrier  240  is moved proximally to swallow the lead A, proximal clamping ring  290  remains in the same angular position (although it is moved axially) and distal clamping ring  290  is rotated by the lead to a less angled position; and when the carrier  240  is moved distally to reset, the distal clamping ring  290  returns, due to the lead (and assisted by spring  302 ), to the tilted (angular) position to prevent reverse relative movement with the lead and the proximal clamping ring  260  is tilted by the lead A to a less angled (move vertical) position. Such rotation or tilting of proximal clamping ring  260  compresses the biasing spring  266 . 
     Note that the proximal and distal clamping rings  260 ,  290  do not perform a clamping function when they are not sufficiently tilted, i.e., when they are in a substantially vertical position. The springs  266 ,  302  aid the clamping rings  260 ,  290  in making the initial tilting to a more angled position. As soon as the clamping rings  260 ,  290  start locking on the lead as a result of relative axial movement, the tilting increases and the locking force increases. The greater the force, the better the locking on the lead. 
     The above steps of  FIGS.  25 - 29    are then repeated the desired number of times by actuation of the trigger (actuating member)  340 . As can be appreciated, the trigger or actuator  340  is repeatedly pulled and released, to cause progressive and incremental relative movement of the extractor  200  and lead A to cut, e.g., sever and/or dissect, tissue adjacent the lead and “swallow” the lead A to free the lead from the surrounding tissue so it can be removed from the body. As can also be appreciated, this movement and tunneling action of the extractor  200  results in the removal force applied at the distal end of the device, adjacent the tissue engagement of the lead. 
     In certain instances it may be desirable to quickly abort the procedure and quickly remove the extractor  200  from the lead. This requires the clamping rings  260 ,  290  to be moved to the less tilted unclamping position. This is shown in  FIGS.  43  and  44   .  FIGS.  41  and  42    show normal use of the trigger  352 . As noted above, when trigger  340  is pulled back, it pulls back on cable  331  to retract the carrier  240 ; when trigger  340  is moved forward (distally), it pushes the carrier  240 . This is the normal use of trigger  252  to achieve desired movement of the carrier and relative movement (“swallowing”) of the lead. However, if during the procedure, the user desires to quickly remove the extractor  200 , the trigger  340  is moved to its forwardmost (distalmost) position to move the carrier  240  to an advanced override position. This override position is distal of the carrier position of  FIGS.  25  and  30   . In this position, the carrier  240  is advanced so the distal edge  275  of upper support  274  contacts a proximal end  290   a  of distal clamping ring  290  forcing it to a less tilted position, and in some embodiments a position close to about 90 degrees with respect to the longitudinal axis of the lead A. Such movement of the carrier  240  with respect to the lead A also causes the proximal clamping ring  260  to move to the less tilted position as it does in  FIGS.  27  and  28   . Thus, with the less tilted position and larger gaps of the openings  292  and  264  in clamping rings  290 ,  260  with respect to the outer diameter of the lead, the extractor  200  can more freely slide over the lead A and be removed from the patient&#39;s body. Note a detent can be provided to limit movement of the trigger to the position of  FIG.  41   , and then overridden by application of sufficient force to move the trigger to the override position. Alternatively, a latch or other locking mechanism can be provided to restrict movement of the trigger to the position of  FIG.  41   , and released to allow movement of trigger  340  to the position of  FIG.  43    to cancel the procedure. Also, a retention mechanism can be provided to retain the trigger in the override position. 
     Note in some embodiments the trigger  340  can be in the neutral position of  FIG.  41    and then return to the position of  FIG.  41    when released from the position of  FIG.  42   . Also, the trigger mechanism can include a stop such as a detent, which would prevent movement of the trigger  340  to the override position of  FIG.  43    during its normal use, and require sufficient force of the trigger  340  to override the detent to force it into the override position of  FIG.  43   . 
     Note alternatively an external power source such as a motor can be provided to electrically drive (actuate) the cable  333  instead of manual operation by the user. 
     In an alternate embodiment illustrated in  FIGS.  37 - 40   , a flexible sheath  370  is provided which enables unscrewing of the lead at the distal end. The sheath  370  also has sufficient rigidity to allow for rotation. The lead extractor  200 ′ is the same as lead extractor  200  except for the provision of the sheath positioned over a portion of the extractor  200 ′. The extractor  200 ′ is used in the identical fashion as extractor  200  described above to separate the lead from the tissue encapsulating the lead along its length. Therefore, for brevity, the components of the extractor  200 ′ and their function will not be repeated herein as they are identical to extractor  200 , and identical components, e.g., outer housing  202 ′, distal clamping ring  290 ′, and proximal clamping ring  260 ′ are labeled with “prime” designations. The sheath  370  is attached to the proximal end cap  249 ′ of the inner tube  204 ′ and extends proximally of the end cap  249 ′, forming an extension of the inner tube  204 ′. After the extractor  200 ′ has completed its tunneling action as described above and the lead A is free from tissue proximal to its embedded distal end, the flexible sheath  370  is rotated ( FIG.  38   ), which in turn rotates the extractor  200 ′. Since the lead A is firmly clamped by the extractor  200 ′, rotation of the sheath  370  also rotates the lead A, thereby unscrewing the distal tip B of the lead A which is embedded in tissue ( FIG.  39   ). The sheath  370 , extractor  200 ′ and clamped lead A can then be removed from the body as shown in  FIG.  40   . 
     Although described for extracting a lead, the extractors of the present disclosure can also be utilized in other surgical applications. 
     While specific embodiments have been described above, it will be appreciated that the invention may be practiced otherwise than as described. Moreover, specific items discussed with reference to any of the isolated drawings may freely be inter-changed supplementing each outer in any particular way. The descriptions above are intended to be illustrative, not limiting. Thus, it will be apparent to one skilled in the art that modifications may be made to the invention as described in the foregoing without departing from the scope of the claims set out below.