Patent Publication Number: US-2007112343-A1

Title: Surgical tip device with retractable sheath and methods for using same

Description:
FIELD OF THE INVENTION  
      The invention relates to devices, and methods for using the devices, for electrosurgery and more specifically to a surgical tip device that has a retractable sheath that reduces the risk of injury to patients and medical personnel.  
     BACKGROUND OF THE INVENTION  
      Radiofrequency (RF) and laser sources are commonly employed in surgery through a hand held activator, that are capable of delivering a variety of currents and energy levels for coagulation, cutting and tissue stimulation. The terminal section of the hand held delivery system applies the energy typically through a detachable tip. Such tips are available in many shapes and sizes. The tips used for conventional surgery are either blunt or needlepoint. The needlepoint electrode offers significant advantages over larger and/or blunt tipped electrodes. The fine point of a needle improves accuracy to dessicate, diminishes RF scattering during coagulation and increases the versatility of electrosurgery, especially within the pediatric surgical population. Moreover, the widespread acceptance of minimally invasive surgical techniques and laparoscopy will usher in wider applications for needle tip delivery systems.  
      However, needlepoint electrodes have several drawbacks. Significant morbidity to both the patient and the entire surgical team is associated with the needlepoint electrode. The needlepoint is sharp enough to penetrate a vital organ or major vascular structure if inadvertently dropped into an open incision. The surgeon and allied health personnel are also at significant risk for puncture wounds during surgical procedures. As such, in view of the further risk of contracting HIV and Hepatitis viruses through puncture wounds, many operating rooms avoid using the needlepoint system.  
      In addition to the health risks, surgical tips, such as the fiber optic tips associated with surgical laser devices, are somewhat fragile and susceptible to damage if handled roughly or scratched on their surgically active surfaces.  
      Some devices are known that include either retractable electrodes, such as the jaw-like retractable blades disclosed in U.S. Pat. No. 5,456,684 and the complex retractable, adjustably angled needlepoint devices disclosed in U.S. Pat. Nos. 5,366,490 and 5,456,684. However, these devices are limited to very specific uses, they are complex and are not adapted for delivering finely directed and easily manipulated energies currently available for surgical uses.  
     SUMMARY OF THE INVENTION  
      It is therefore a primary object of this invention to provide a surgical tip that is accurate, versatile and safe, and to provide methods for using the tip.  
      It is a further object of this invention to provide a safe, surgical tip that is particularly suited for use within the pediatric surgical population.  
      It is a further object of this invention to provide a surgical tip that is adapted to deliver coagulating and cutting currents.  
      It is a further object of this invention to provide a retractable sheath for surgical tips that is disposable and enhances the safety of electro or laser surgery to both personnel and patients.  
      The retractable sheath of the surgical tip of the invention was designed to provide a beneficial alternative to the deployable needlepoint electrode disclosed in U.S. Pat. No. 6,569,161B2. The deployable needlepoint electrode disclosed in the &#39;161 patent offers many of the same advantages as the subject invention, however, the applications will likely differ somewhat depending on the surgical conditions. In the subject invention,.the sheath protecting the surgical tip is retracted back from the tip towards the handle of the device when in use as opposed to the deployable needle disclosed in the &#39;161 patent that is pushed out from a fixed sheath to expose the electrode tip when in use. In the subject invention the needle remains fixed in position relative to the handle and the sheath is moved back and forth. The subject invention also includes the combination if desired in which the sheath and the surgical tip may both be adjusted or otherwise movable.  
      A preferred embodiment of the surgical tip device of the invention generally comprises: a proximal handle; a distal surgical member, having a surgical tip, and at least temporarily fixed to the handle; a retractable sheath that at least partially covers the surgical tip; and a means for retracting the sheath backwards from the tip towards the handle to at least partially uncover the tip. The device may further comprise a means located on the handle for activating the surgical tip. The surgical tip may comprise one or more tips such as, but not limited to, a needle point electrode, a blunt electrode, a fiber optic laser probe, a cryogenic probe, a paddle, a ball, and a loop The means for retracting may take a variety of forms including but not limited to a plurality of threads on the sheath and a corresponding plurality of threads on the handle; and/or one or more tension spring members between the sheath and the handle.  
      The sheath may also comprise a contact-activating member and the handle may likewise comprise one or more corresponding activation contacts. The device preferably further comprises a safety means for preventing unintentional activation of the surgical tip, wherein the safety means may comprise a housing on the handle that at least partially encloses the means for activating the surgical tip.  
      Another preferred embodiment of the surgical tip device of the invention generally comprises: a proximal handle having an electrode receptacle and a sheath receptacle having a plurality of threads; a distal electrode surgical member, having a distal electrode surgical tip, and a proximal electrode end that is at least temporarily fixed in the electrode receptacle; a retractable sheath at least partially covering the tip and having a plurality of threads corresponding to the threads of the sheath receptacle ; and a means for activating the surgical tip. The sheath receptacle threads may be provided on an inside surface of the handle, in which case the retractable sheath threads are preferably provided on an outside surface of the retractable sheath.  
      A preferred method of the invention for using a surgical tip device, generally comprises the steps of: providing a surgical tip comprising, a proximal handle; a distal surgical tip, having a surgically active tip, and at least temporarily fixed to the handle; a retractable sheath that at least partially covers the surgically active tip; and a means for retracting the sheath backwards from the tip towards the handle to at least partially uncover the tip; retracting the sheath to uncover the tip; and activating the surgically active tip.  
      The means for retracting may comprise a means for at least partially rotating the sheath around the surgical tip, wherein the means for rotating may comprise a plurality of threads provided on the sheath and a plurality of corresponding threads provided on the handle; and/or one or more grooves on the sheath and a detent on the handle.  
      The surgical tip device may further comprise a means for activating the surgically active tip wherein the means for activating then preferably comprises one or more contact activating members on the sheath and one or more activation contacts on the handle. The device used in the method may still further comprise a safety means for preventing unintended activation of the currents, wherein the safety means comprises one or more detents on the sheath and one or more activation members at least partially enclosed in a housing on the handle. The housing may comprise an opening through which the detent is adapted to engage the activation member when the sheath is retracted.  
      Another preferred method for using the surgical tip device of the invention that is adapted to deliver adjustable levels of energy to a surgical site, generally comprises the steps of, providing a surgical tip device comprising, a proximal handle; a distal surgical member, having a surgically active region, and at least temporarily fixed to the handle; a sheath that at least partially covers the surgically active region; and a means for adjusting the relative positions of the sheath and the surgically active region, backwards to and forwards from the handle, to variably expose the surgically active region of the distal surgical member; activating the surgical tip; and adjusting the level of energy at the surgical site by variably exposing one or more areas of the surgically active region of the distal surgical member.  
      The invention is adapted to deliver laser or electro energies at its tip that are protected within a retractable sheath that is retracted when the surgical tip device is in use. The invention is particularly suited for incorporation into a handle hand device much like a ballpoint pen except that the sheath is retracted rather than the tip deployed. A variety of means are disclosed for retracting the sheath. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      Other objects, features and advantages will occur to those skilled in the art from the following description of the preferred embodiments and the accompanying drawings in which:  
       FIG. 1A  is a side view of a preferred embodiment of the surgical tip device of the invention showing the sheath in a non-retracted position;  
       FIG. 1B  is a side view of the embodiment shown in  FIG. 1A  showing the sheath in a retracted, surgical position;  
       FIG. 2A  is a side view of another preferred embodiment of the surgical tip device of the invention showing the sheath in a non-retracted position;  
       FIG. 2B  is a side view of the embodiment shown in  FIG. 2A  showing the sheath in a retracted, surgical position;  
       FIG. 3  is a side view of another preferred embodiment of the surgical tip device of the invention showing the sheath in a non-retracted position;  
       FIG. 4  is a side view of the embodiment shown in  FIG. 3  showing the sheath in a retracted, surgical position;  
       FIG. 5  is side-by-side view of another embodiment of the sheath and the forward section of the handle showing another means for retracting the sheath of the invention;  
       FIG. 6  is side-by-side view of another embodiment of the sheath and the forward section of the handle showing another means for retracting the sheath of the invention;  
       FIG. 7  is a side view of another embodiment of the surgical tip and sheath of the invention with the sheath fully retracted and the sheath fully enclosing the surgical tip;  
       FIG. 8  is a side view of the embodiment of the surgical tip and sheath of the invention shown in  FIG. 7  with the sheath fully retracted and the sheath partially retracted. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS AND METHODS  
      The invention generally features a sheath that protects a surgical tip device, such as a needlepoint electrode or laser tip, by surrounding the tip while the tip is not in use and then is retracted backwards from the tip towards the handle away from the tip to expose the tip when the surgical tip is in use. The preferred embodiments of the device of the invention are shown in the Figures.  
      The first described embodiment is shown and generally referred to in  FIGS. 1A and 1B  as device  10 . As with all of the embodiments described herein, device  10  can be readily inserted into currently available hand held systems, connected to a generator and then thrown away after a single use.  
      Device  10  comprises proximal handle  14  having an electrode receptacle  30  into which the proximal end of electrode  21  is inserted and at least temporarily fixed in place. Electrode  21  is one example of the surgical tip of the invention. Other surgical tips include but are not necessarily limited to, needles, paddles, ball-ends, lasers, cryogenic tips, and probes. The surgical tip device of the invention may be used in all surgical specialities such as, but not limited to, urological, endoscopic, laparoscopic, neurology, cardiology, orthopedic, gynecological, colorectal, vascular, and opthalmic. The device of the invention may also include a light source and/or an irrigation canal proximate the surgical tip end.  
      Device  10  further comprises needle sheath  16  having a finger grip  12  with a finger tab  28 . Finger tab  28  may be an ergonomically molded depression in grip  12  as shown in  FIG. 1A  or other suitable gripping means such as one or more raised asperities on the surface of grip  12 . Device  10  is shown with the components concentrically or telescopically arranged so that the outside diameter of the needle  18  with needle or electrode tip  20  is smaller than the inside diameter of sheath  16 . In turn, sheath  16  has an outside diameter that is smaller than the inside diameter of receptacle  30 . The outside surface of receptacle  30  then increases gradually or frustoconically to a larger diameter and more ergonomically sized handle  14  for gripping. Device  10  further comprises bridge  23  that extends out laterally from sheath  16  to grip  12  to enable grip  12  to be pull backwards towards handle  14 . Depending on the distance that grip  12  is pulled backwards, bridge  23  allows grip  12  to clear the outside surface of handle  14 .  
      Device  10  also comprises tension spring  22  that is seated concentrically around needle electrode  21  between the rearward end of sheath  16  and the forward end of receptacle  30 . Tension spring  22  places forward pressure on sheath  16  to maintain sheath  16  in a non-retracted position when not actively being pulled backwards. Inner shoulders (not shown) may be provided on the inner forward end of sheath  16  and the inner rearward end of receptacle  30  against which spring  22  may be seated inside the inner tubular sides of sheath  16  and receptacle  30 . Sheath  16  may further comprise a second telescoping member (not shown) between the forward section of sheath  16  and handle  14  to fully enclose needle electrode  21  when spring  22  is in a relaxed state and needle tip  20  is fully enclosed as shown in  FIG. 1A . When grip  12  is pulled backwards in the direction of arrow A towards handle  14 , sheath  16  retracts from the distal end of needle  18  to expose needle tip  20  as shown in  FIG. 1B .  
      Handle  14  is also provided with two buttons  24  and  26  for engaging, respectively, the cutting and coagulating currents carried over electrode  21  to the surgical site. Buttons  24  and  26  may be provided with a safety to prevent them from engaging the electrical current unless sheath  16  is in a retracted position.  
      The retracting sheath not only protects the surgical tip from damage and users from injuries, as importantly, it also enables the user to control the level and intensity of the energy delivered at the surgical site. For example, the level and density of the electrical energy delivered to the surgical site using a surgical electrode may be increased or decreased, respectively, by decreasing or increasing the exposed area of the surgically active tip. The intensity or power at the surgical tip may be increased by reducing the active area at the distal end of the surgical tip through which the same amount of electrical energy is delivered at the surgical site. The same is true of laser energy delivered through an optical fiber tip.  
      The adjustment of power may also be achieved by moving the surgical tip relative to the sheath, as opposed to moving the sheath relative to the surgical tip. A number of means for retracting or moving the needle relative to the sheath are described in U.S. Pat. No. 6,569,161B2 issued on May 27, 2003 to S. Zappala and is hereby incorporated by reference to described such means.  
      Another embodiment of the needlepoint electrode device of the invention is shown in  FIGS. 2A and 2B  and is generally referred to as device  40 . Similar to device  10 , needlepoint electrode device  40  comprises proximal handle  42  having an inner electrode receptacle.  41  into which the proximal end of electrode is inserted and at least temporarily fixed in place. Device  40  further comprises needle sheath  56  having a finger grip  44  with a finger tab  48  integrally and ergonomically molded into grip  12  as shown in  FIG. 2A . Device  40  is shown with the components concentrically or telescopically arranged so that the outside diameter of the needle  18  with needle or electrode tip  20  is smaller than the inside diameter of sheath  16 . In turn, sheath  16  has an outside diameter that is smaller than the inside diameter of receptacle  30 . Device  40  further comprises bridge  45  that extends out laterally from sheath  58  to grip  44  to enable grip  44  to be pull backwards towards handle  42  in the direction of arrow B and turned in the direction of arrow D.  
      Bridge  45 , in this embodiment allows grip  44  to clear the outside surface of button housing  46 . Button housing  46  acts as a type of safety to prevent buttons  52  and  54  from being activated when sheath  58  is not retracted. Grip  44  further comprises detent  50 , which is adapted to be inserted into opening  55  in the top of button housing  46  to engage buttons  52  and  54  when sheath  58  is retracted. Depending on the height of bridge  45  or the thickness of detent  50 , bridge  45  may be elastomeric to enable grip  44  to be depressed in the direction of arrow C so that detent  50  engages buttons  52  and  54  when inserted into openings  55 . The elasticity of bridge  45  will depend on the material used but should offer a degree of resistance when depressed to ensure that detent  50  spontaneously disengages from buttons  52  and  54  when finger tab  48  is released. If continuous current is desired without having to continuously depress tab  48 , a releasable or resistive catch may be provided on detent  50  or housing  46 , or any other suitable surface, to temporarily maintain detent  50  in position against one of the buttons.  
      Another preferred embodiment is shown in  FIGS. 3 and 4  and generally referred to as needlepoint electrode device  70 . Device  70  comprises a pen body or handle  72  with a threaded electrode receptacle  80  and a correspondingly threaded sheath  74 . Handle  72  is also provided with a non-threaded receptacle  82  into which the proximal end of the electrode is inserted and at least temporarily fixed or otherwise held is place. Sheath  74  is provided with a finger knob  76  that is used to provide a grip on sheath  74  to rotate sheath  74 . Sheath  74  is rotated is the direction of arrow F to move sheath  74  forward and backwards in the direction of arrow E. Threads  84  are provided on the outside surface-of sheath  74  that correspond to threads  78  provided on the inside surface of threaded receptacle  70 . When sheath  74  is rotated in one direction, sheath  74  retracts backwards from the distal end of the needle tip towards the handle to expose the surgically active needle electrode tip during surgical procedures. When sheath  74  is rotated in the opposite direction, sheath  74  moves forward again to recover tip  76  of the needle electrode. The extent to which sheath  74  is rotated in either direction of arrow E will determine the density of the energy delivered at the surgical tip assuming that the current level remains the same. The amount and density of the energy delivered may be adjusted by varying the area of the exposed surgical tip and by raising and lowering the current at the generator or other energy source. Such adjustments, either at the surgical tip or at the generator, can be used to alternate between coagulating and cutting modes.  
      Although buttons  24 ,  26 ,  52 , and  54  are described as a means for activating the RF current of the device and may be used with any of the embodiments described, other suitable means for activating may be used. Such means include but are not limited to one or more switches located on the device itself or at location remote from the device, or contacts provided on opposing inner or outer surfaces of the retractable sheath and the handle. In the latter instance, activation is achieved when the sheath is retracted and a contact on the sheath touches one or more corresponding contacts on the handle or handle receptacle.  
      Although not meant to be limiting,  FIGS. 5 and 6  illustrate two other means for retracting the sheath of the invention. Sheath  90 , shown in  FIG. 5 , comprises a tab or detent  92 , and handle receptacle  94  comprises a corresponding notched groove  96  on the inner surface. If desired, the detent and groove may be provided instead on the inside surface of the receptacle and the outside surface of the sheath, respectively. To retract sheath  90 , sheath  90  is rotated backward along groove  96 . In the embodiment shown, sheath  90  may be adjusted to three different positions at stops  98 ,  100  and  102 . Any number of position stops may be provided as needed.  
      Similarly, sheath  110 , shown in  FIG. 6 , comprises a detent  112 , and handle receptacle  114  comprises a corresponding notched groove  124 . In the non-retracted position, tab or detent  112  is seated in stop  120 . To retract sheath  110 , the sheath is pulled slightly forward, to release the detent from  120 , rotated counterclockwise along lateral groove  118 , then pulled backwards toward the handle until it butts up against the proximal end of groove  124 , and then rotated counterclockwise again and released so that detent is seated in stop  122 . To move sheath  110  forward again to protect the needle electrode tip the reverse steps are taken. Sheath  110  is pushed forward slightly to release the detent from stop  122 , then rotated clockwise, the pushed forward along groove  124  until it butts up against groove  118 , and rotated again clockwise and released to seat again in stop  120 .  
      Another embodiment of the surgical tip and sheath of the invention are shown in  FIGS. 7 and 8 . The distal end of device  130  comprises metal surgical loop  132  and retractable sheath  134 . In  FIG. 7B , the surgical tip of loop  132  is shown fully exposed when sheath  134  is fully retracted in the direction of arrow G. In  FIG. 7A , the surgical tip of loop  132  is fully enclosed and protected when sheath  134  is in a closed position. As shown in  FIGS. 8A and 8B , the diameter, and therefore size, of the distal end of surgical loop  132  may be adjusted by only partially retracting sheath  134 . As shown in  FIG. 8B , the diameter H of loop  132  is at its maximum when sheath  134  is fully retracted. Yet, as shown in  FIG. 8A , the diameter I of loop  132  is reduced when sheath  134  is only partially retracted. By adjusting the extent to which sheath  134  is retracted, either or both the density of energy delivered at the surgical site and the size of the loop may be modified to suit the surgical application.  
      In addition to the various means for retracting the sheath that are shown in the drawings other means, although not limiting, may comprise corresponding elastomeric materials on the outside of the sheath and the inside of the handle, and/or any other materials or surface asperities that would provide a frictional or mechanical means for retracting the sheath from the needle electrode tip and at least temporarily maintaining the sheath in a retracted position.  
      The needlepoint electrode of the invention has a surgically active tip that is adapted to deliver both coagulating and cutting currents. The device of the invention is preferably insulated over  80 % of its electrode surface to reduce scatter and the inadvertent delivery of current through tissue that may come into contact with the shaft of the device. The sheath, in addition to any of the other components of the device of the invention, may be made from electrically and/or thermally insulating materials to reduce or prevent electrocution or burns.  
      The method of the invention for using a surgical radio frequency needlepoint electrode begins by providing a surgical radio frequency electrode device, such as devices  10 ,  40  and  70 , and inserting the device into a hand held device that is connected to an RF generator. The surgically active region of the needlepoint electrode is then exposed by retracting the needlepoint sheath from the needlepoint tip by pulling backwards on the sheath, as in devices  10  and  40  or by turning the sheath to rotate and move the sheath backwards as in device  70 . After the electrode top is exposed, the surgeon activates the surgically active region to the tip by initiating a current for cutting and/or coagulating through the electrode by depressing the appropriate button or otherwise engaging the activating contact. After the tissues are cut, ablated and/or coagulated as needed, the surgically active region of the needlepoint electrode covered by releasing the pressure on the grip of devices  40  and  70  or by rotating the sheath of device  70  forward to allow the sheath to surround and protect the distal tip of the needlepoint electrode.  
      Although specific features of the invention are shown in some drawings and described in connection with one embodiment, and not others, this is for convenience only as some feature may be combined with any or all of the other features in accordance with the invention.  
      Other embodiments will occur to those skilled in the art and are within the following claims: