Abstract:
A surgical probe is disclosed which includes a stiff treatment waveguide extending between a first end and a second end, the first end being adapted for connection to a handpiece, the second end being adapted for insertion through an incision into an area of tissue. The treatment waveguide in configured to receive treatment light from the handpiece at the first end, transmit the light to the second end, and emit the light from the second end into a portion of the tissue proximal the second end. The treatment waveguide is adapted to penetrate through a portion of the area of tissue in response to pressure applied to the handpiece.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims benefit to each of U.S. Provisional Application Ser. No. 60/987,596, filed Nov. 13, 2007, U.S. Provisional Application Ser. No. 60/987,617, filed Nov. 13, 2007, U.S. Provisional Application Ser. No. 60/987,819, filed Nov. 14, 2007, U.S. Provisional Application Ser. No. 60/987,821, filed Nov. 14, 2007, U.S. Provisional Application Ser. No. 61/018,727, filed Jan. 3, 2008, U.S. Provisional Application Ser. No. 61/018,729, filed Jan. 3, 2008, and U.S. Provisional Application Ser. No. 60/933,736, filed Jun. 8, 2007, the contents each of which are incorporated by reference herein in their entirety. 
     
    
     BACKGROUND 
       [0002]    The present invention relates to a surgical waveguide. Plastic surgeons, dermatologists, and their patients continually search for new and improved methods for treating the effects of an aging or otherwise damaged skin. One common procedure for rejuvenating the appearance of aged or photodamaged skin is laser skin resurfacing using a carbon dioxide laser. Another technique is non-ablative laser skin tightening, which does not take the top layer of skin off, but instead uses a deep-penetrating laser to treat the layers of skin beneath the outer epidermal layer, tightening the skin and reducing wrinkles to provide a more youthful appearance. 
         [0003]    For such techniques as laser skin tightening treatment, it has been difficult to control the depth and amount of energy delivered to the collagen without also damaging or killing the dermal cells. Much of the energy of the treatment pulse is wasted due to scattering and absorption in the outer epidermal layer, and the relatively high pulse energy required to penetrate this outer layer can cause pain and epidermal damage. 
         [0004]    Some skin tightening techniques include using a hollow tubular cannula that contains an optical fiber connected to a laser source. The cannula can be inserted subcutaneously into a patient so that the end of the fiber is located within the tissue underlying the dermis. The source emits a treatment output, for example an output pulse that is conveyed by the fiber to the dermis, which causes collagen shrinkage within the treatment area, thus tightening the skin. 
         [0005]    A technical complication common to the use of cannula sheathed optical fibers for surgical applications is the break off of fatigued fiber ends (‘tips’). Additionally, an improperly tightened optical fiber can slide up into the cannula such that the fiber tip is located within the cannula air space. This can cause very high cannula and fiber tip temperatures with corresponding excessive temperatures coupled to adjacent tissue. The susceptibility of standard optical fibers to tip breakage is worsened by autoclave cycles and by long duration high power use. 
       SUMMARY OF THE INVENTION 
       [0006]    In one aspect, the inventors have realized that a surgery tool employing a robust waveguide can be used in an invasive laser surgical procedure. Use of such a waveguide can eliminate the need for a cannula, as the waveguide may be inserted directly into the incision. This improves both safety and efficacy in that broken and lost optical fiber tips are avoided. Further, this reduces or eliminates the possibility of the waveguide slipping up into a cannula or catheter and operating within an air filled space in the cannula or catheter, leading to excessive waveguide tip temperature rise. 
         [0007]    In another aspect, the inventors have realized that including infrared (IR) temperature sensing with a laser surgical device of the type described above, or otherwise, allows for temperature monitoring of a treatment area. Temperature information can be used as a feedback to control the applied treatment. 
         [0008]    In some embodiments, a surgery tool or a surgical probe includes a stiff treatment waveguide extending between a first end and a second end, the first end being adapted for connection to a handpiece, and the second end being adapted for insertion through an incision into an area of tissue. In some embodiments, the treatment waveguide is configured to receive treatment light from the handpiece at the first end, transmit the light to the second end, and emit the light from the second end into a portion of the tissue proximal the second end. 
         [0009]    In some embodiments, the treatment waveguide is adapted to penetrate through a portion of the area of tissue in response to pressure applied to the handpiece. In some embodiments, the treatment waveguide is substantially free of external mechanical support. The treatment waveguide is free from an external cannula. 
         [0010]    In some embodiments, the treatment waveguide includes an optical fiber having a diameter of about 1000 μm to about 2000 μm. The treatment waveguide may be composed of one or more materials selected from the list of: glass, plastic, quartz, and Nd glass, and a Cerium-doped quartz. A treatment waveguide composed of a glass may be sheathed in a plastic coating to prevent fragments and shards from an accidental break from contaminating a treatment site. 
         [0011]    In some embodiments, the surgical probe of the sensing waveguide is adapted to transmit treatment light at wavelengths of about 532 nm to about 1550 nm. The second end of the treatment waveguide comprises a strip and cleave tip. The second end of the treatment waveguide comprises one selected from the group of: a wedge shaped tip, an angled tip, or a side firing tip. 
         [0012]    In some embodiments, the first end of the treatment waveguide is adapted for detachable connection to the handpiece. In some embodiments, the handpiece itself includes one or more optical elements adapted to direct light from a light source to the first end of the treatment waveguide. The handpiece may further include: a sterile sheath defining an interior volume and an exterior volume, where the one or more optical elements are positioned within the interior volume and the treatment waveguide is positioned in the exterior volume, and a connector adapted to receive the first end of the treatment waveguide and to optically couple first end of the treatment waveguide to the one or more optical elements while preventing pneumatic communication between the interior and exterior volumes. 
         [0013]    In some embodiments, the treatment waveguide is adapted to receive infrared light from an area of tissue proximal the second end of the sensing waveguide, direct the infrared light to the first end of the sensing waveguide, and emit the infrared light onto a infrared temperature sensor located within the handpiece. 
         [0014]    In some embodiments, the surgical probe further includes a sensing waveguide extending between a first end proximal the first end of the treatment waveguide and a second end proximal the second end of the treatment waveguide, where the waveguide is adapted to receive infrared light from an area of tissue proximal the second end of the sensing waveguide, direct the infrared light to the first end of the sensing waveguide, and emit the infrared light onto a infrared temperature sensor located within the handpiece. 
         [0015]    In some embodiments, the surgical probe sensing waveguide is coaxial with the treatment waveguide. In some embodiments, the sensing waveguide comprises an optical fiber positioned beside the treatment waveguide. In some embodiments, the sensing waveguide is relatively less stiff than the treatment waveguide, and further includes an overjacket surrounding the treatment waveguide and the sensing waveguide adapted to secure the treatment waveguide and the sensing waveguide in fixed relative position. The sensing waveguide is adapted to transmit light at wavelengths of about 5 μm to about 14 μm. The treatment waveguide may be composed of ZnSe. 
         [0016]    In some embodiments, the surgical probe further includes: the handpiece, the temperature sensor, and a processor, where the temperature sensor is configured to detect one or more properties of the infrared light from the first end of the sensing waveguide, and where the processor is configured to determine information indicative of the temperature of the tissue area of tissue proximal the second end of the sensing waveguide based on the one or more detected properties of the light. 
         [0017]    In some embodiments, the surgical probe further includes an optical element configured to separate a first portion of the infrared light at a first wavelength and a second portion of the infrared light at a second wavelength, where the temperature sensor is configured to detect a property of the first portion and a property of the second portion, and the processor is configured to determine information indicative of the temperature of the area of tissue proximal the second end of the sensing waveguide based on the property of the first portion and the property of the second portion. 
         [0018]    In some embodiments, the processor is configured to determine information indicative of the temperature of the tissue area of tissue proximal the second end of the sensing waveguide based on the property of the first portion and the property of the second portion by comparing the properties. In some embodiments, the processor is configured to control the treatment light based on the determined information indicative of the temperature of the area of tissue. 
         [0019]    In some embodiments, a method is defined including: providing a stiff treatment waveguide extending between a first end and a second end, the first end connected to a handpiece, the second end being adapted for insertion through an incision into an area of tissue, where the treatment waveguide being substantially free of external mechanical support. The method further includes: inserting said waveguide into an incision in a patient, applying pressure to the handpiece to advancing said waveguide through an area of tissue, providing treatment light directed from a treatment source to the handpiece, directing treatment light to the first end of the treatment waveguide, transmitting the light from the first end to the second end, and emitting the light from the second end into a portion of tissue proximal the second end. 
         [0020]    In some embodiments, the method may specify the treatment waveguide is free from an external cannula. The method further may include: repetitively advancing and withdrawing the treatment waveguide along multiple paths through the area of tissue and applying treatment light to multiple areas of tissue along the multiple paths. The method may further include: providing a sensing waveguide extending between a first end proximal the first end of the treatment waveguide and a second end proximal the second end of the treatment waveguide, receiving infrared light from an area of tissue proximal the second end of the sensing waveguide, directing the infrared light to the first end of the sensing waveguide, and emitting the infrared light onto a infrared temperature sensor located within the hand piece. 
         [0021]    In some embodiments, using the temperature sensor, the method may further specify detecting one or more properties of the infrared light from the first end of the sensing waveguide and determining information indicative of the temperature of the tissue area of tissue proximal the second end of the sensing waveguide based on the one or more detected properties of the light. In some embodiments, the method further includes controlling application of the treatment light based on the determined information indicative of the temperature of the area of tissue. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. 
           [0023]      FIG. 1  shows a first view of a surgical waveguide 
           [0024]      FIG. 2  shows a second view of a surgical waveguide. 
           [0025]      FIG. 3  shows an partial assembly drawing of a surgical waveguide. 
           [0026]      FIG. 4  shows an assembly drawing of a connection between the surgical waveguide and an optics focus interface to a fiber optic line. 
           [0027]      FIG. 5  shows a collection of surgical waveguide tips designs. 
           [0028]      FIG. 6  shows a surgical waveguide integrated with a thermal temperature sensor. 
           [0029]      FIG. 7  shows a cross sectional view of the optics focus interface between the surgical waveguide and a fiber optic line. 
           [0030]      FIG. 8  shows a plot of radiation transmission vs. wavelength for a ZnSe sense fiber with an anti-reflection (AR) coating. 
       
    
    
     DETAILED DESCRIPTION 
       [0031]      FIGS. 1 and 2  show a first and a second view of a surgical waveguide adapted for use in a subdermal tissue ablation procedure according to an embodiment.  FIGS. 1 and 2  show a laser surgical waveguide assembly  100  including a hand piece  105  which receives a surgical waveguide  110 . The surgical waveguide  110  is chosen to have suitable mechanical, material, and optical properties for surgical applications without need for a supporting cannula. That is, the surgical waveguide  110  itself may be inserted through an incision directly into a patient&#39;s tissue for the delivery of therapeutic laser light. For example, the waveguide may be chosen to be mechanically strong and/or stiff enough to withstand multiple aggressive passes into fibrous tissue, while being capable of transmitting high power laser pulses. Further, the waveguide may be chosen to be mechanically strong and/or stiff enough to maintain control of a surgical waveguide  110  tip, such that the surgical waveguide  110  body undergoes a minimum of flexure under a compressive or shear force applied by the hand piece  105 . In some embodiments, the waveguide may be removable, disposable, and/or consumable 
         [0032]    For example, in some embodiments, the surgical waveguide  110  can be a relatively short (e.g., about 6″ or less) length of large core fiber having a large diameter (e.g. about 1000 μm or more, about 1000-2000 μm, or greater than 2000 μm. The cost for such a fiber is low due to the short fiber length, but due to its large diameter, the fiber has sufficient mechanical strength to meet the requirements of surgical applications. The larger diameter of the fiber at the fiber tip lowers the power density at the tip and may add to the longevity of the fiber tip. In some embodiments, the surgical waveguide is a consumable, large diameter, (e.g., 1800 μm) optical fiber with a strip and cleave tip. In such embodiments, as the tip of the fiber becomes worn with use, it may be removed, and the exposed fiber end may be cleaved to provide a new operating tip. 
         [0033]    In some embodiments, the surgical waveguide  110  comprises a stiff glass or plastic waveguide suitable for surgical applications without the need for a cannula. Other suitable waveguide materials include glass or quartz rods with some sort of cladding, hollow tubing with dielectric coatings, Nd glass, and Cerium-doped quartz. In some embodiments, waveguides made of glass are sheathed in a plastic coating analogous to a safety glass to retain glass fragments and shards within the plastic coating if the glass breaks, and greatly reducing the possibility of glass fragments and shards contaminating a treatment site. In various embodiments, the surgical waveguide  110  requires a cladding material. The cladding material may be selected to add necessary strength and stiffness to the surgical waveguide  110 , eliminating the need for cannula. Although several examples of waveguide types have been provided, it is to be understood by those skilled in the art that any other suitable material or configuration may be used. 
         [0034]    Referring again to  FIG. 1 , the surgical waveguide  110  is held in place in the hand piece  105  by a waveguide chuck  115 . The surgical waveguide  110  protrudes from the back end of the hand piece  105  and is received by a waveguide stop  120 . A treatment laser light from a treatment laser  450  is coupled to a reusable optical fiber  125  which terminates in a connector  130 , for example, an SMA-like connector, which receives the hand piece  105 . 
         [0035]    Light from the reusable optical fiber  125  is coupled into the surgical waveguide  110  using a focusing assembly  135  including, for example, a set of optical elements  140 . The set of optical elements  140  includes, for example, lenses, a single or dual focus mirror, and others. The set of optical elements  140  directs light from the end of the reusable fiber  125  into the surgical waveguide  110 . In some embodiments, an optical coupling can be achieved by placing the end faces of the reusable fiber  125  and the surgical waveguide  110  in contact or close proximity, a technique known as ‘butt-splicing’. Note that, because the reusable fiber  125  is not inserted into the patient, the reusable fiber  125  need not be as physically strong as the surgical waveguide  110 . For example, in some embodiments, the reusable fiber may be a 300-600 μm fiber. 
         [0036]    The surgical waveguide  110  and hand piece  105  may be sterilized using, for example, an autoclave. The reusable fiber  125 , connector  130 , and focusing assembly  135  are covered with a sterile sheath  150 , and thus need not be autoclaved. Note that this allows for the use of, for example, a focusing assembly  135  including optical elements  140  that are not sufficiently robust to undergo one or more autoclave cycles. 
         [0037]      FIG. 3  shows a partial assembly drawing of a surgical waveguide adapted for use in a subdermal tissue ablation procedure according to an embodiment.  FIG. 4  shows an assembly drawing of a connection between the surgical waveguide and an optics focus interface to a fiber optic line according to an embodiment. When connected, the surgical waveguide  110  pierces through the sterile sheath  150 . The sterile sheath  150  is clamped between the hand piece  110  and the connector  130 , thereby maintaining the integrity of the sheath. For example, in some embodiments the hand piece  110  may include a coupling with an O-ring groove  305 . The connector  130  and focus assembly  135  may include a matching O-ring  310 . When connected, the O-ring  310  compresses the sterile sheath  150  against the hand piece  110  O-ring groove  305 , preventing communication between the sterile region inside the sterile sheath  150  and the non-sterile region outside of the sterile sheath  150 . 
         [0038]      FIG. 5  shows a collection of surgical waveguide tips designs according to an embodiment.  FIG. 5  shows several embodiments of surgical waveguides, including a glass waveguide  505 , a consumable optical fiber  510  with strip and cleave end as described above, a hollow metal waveguide  515 , and a quartz waveguide  520 . A collection of waveguide tips with different exemplary configurations are shown, whereby arrows indicate the direction of light emission. The collection of waveguide tips includes: wedge tips  550 , angled tips  555 , and side-firing tips  560 . In some embodiments, the surgical waveguide  110  may be discarded after each use. In some embodiments, the surgical waveguide  110  may be reused multiple times, for example, being sterilized by autoclave between each use. In some embodiments, the surgical waveguide  110  may be discarded after a given number of uses, duration of use, duration of use at a given power level, etc. 
         [0039]      FIG. 6  shows the surgical waveguide integrated with an IR temperature sensor adjacent to the treatment waveguide fiber tip.  FIG. 7  shows a cross sectional view of the optics focus interface between the surgical waveguide and a fiber optic line. An IR waveguide  605 , for example a ZnSe sense fiber, is bundled with the surgical waveguide  110  in an over-jacket  610 . In the example shown, a two sensor IR photodetector assembly  615  is located in the hand piece  105  adjacent to the treatment beam focus assembly  135 . Portions of light from the IR waveguide  605  at two distinct wavelengths are separated and directed respectively to the two IR sensors  620  using, for example, a dichroic beamsplitter  621 . Signals from the two IR sensors  620  are compared differentially to increase sensitivity and reject errors due to a sense waveguide  605  transmission loss variables or characteristics. 
         [0040]    The signals from the two IR sensors  620  are processed to obtain temperature information about a tissue under treatment. IR temperature monitoring provides a tissue temperature feedback to the treatment laser  450 , which may use the tissue temperature feedback to adjust laser energy deposition based on observed tissue temperatures. In various embodiments, adjusting laser energy deposition could include a simple maximum temperature safety limit, or the tissue temperature feedback could allow for a closed loop tissue temperature control. In either case, the treatment laser  450  takes feedback from the IR sense fiber  605 , or equivalently, from an IR sense fiber ring  705 , then adjusts the treatment laser  450  output power in a closed loop to achieve a selected tissue temperature. 
         [0041]    In some embodiments, the surgical waveguide itself can collect IR light from the treatment area during treatment to provide IR tissue temperature sensing. However, for some applications, such a waveguide or fiber would be required to pass high energy treatment laser  450  wavelengths in the range of approximately 532 to 1550 nm and also to pass IR wavelengths on the order of 5-14 μm for temperature sensing and feedback. In some embodiments, this may be an unwanted requirement. Referring back to  FIG. 6  shows an example of a device which avoids this requirement by employing a dual fiber approach. 
         [0042]    As with the systems described above, light at a treatment wavelength is delivered via a surgical waveguide  110 , for example, a stiffened fiber suitable for surgical use without a cannula. As shown in  FIG. 7 , the surgical waveguide  110  is surrounded by and coaxial with an IR waveguide tube  710 , as an example, a ZnSe sense fiber cylinder or tube. As described above, the surgical waveguide  110  is coupled to a treatment fiber  125  which delivers light from a treatment source, in the given example, a treatment laser  450  source. The coupling is accomplished using a focus assembly  135  in a connector  130  connected to the back of the hand piece  105 . As shown in  FIG. 7 , the connector  130  also includes an IR pass filter ring  715  to filter out stray treatment laser  450  light and an IR sense fiber ring  705 , as an example, an annular array of IR photodetectors, aligned with the IR waveguide tube  710 . The IR sense fiber ring  705  produces electrical signals in response to incident IR radiation. The electrical signals corresponding to IR radiation incident to the IR sense fiber ring  705  are directed to a processor  706 , which functions to determine the tissue temperature and to provide a feedback to the treatment laser  450 , as described above. 
         [0043]    As described above, in various embodiments, IR radiation from a treatment site is propagated to an IR photodetector assembly  615  through the IR pass filter ring  715  via the IR sense fiber ring  705  and IR waveguide tube  710 , or via other suitable optics. Other optics suitable to function as the IR waveguide tube  710  may include, for example, anti-reflection (AR) coated ZnSe or Germanium rods or tubes, or certain IR transmissive plastics, or even photonic waveguides.  FIG. 8  shows a plot of radiation transmission vs. wavelength  800  for a ZnSe sense fiber with an anti-reflection (AR) coating as implemented. 
         [0044]    Although several examples of IR optics and geometries are presented, it is to be understood that other suitable materials, geometries, and configurations may be used. 
         [0045]    While this invention has been particularly shown and described with references to example embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention. 
         [0046]    For example, it is to be understood that although in the examples provided above laser light is used for treatment, other sources of treatment light (e.g. flash lamps, light emitting diodes) may be used. 
         [0047]    In some embodiments, a safety accelerometer  160  may be incorporated in the laser surgical waveguide assembly  100 . For example, as shown in  FIGS. 1 and 2 , an accelerometer  160  may by included within the sterile sheath  150  and attached to, for example, the connector  130  or focus assembly  135 . The accelerometer  160  may be attached to, for example, an electronic processor  706  via wiring  161  contained in the sterile sheath  150 . During treatment, the accelerometer  160  measures acceleration of the hand piece  105  and may determine, for example, if the hand piece  105  has come to rest in a single position for too long a period of time, potentially leading to unsafe heating levels, triggering, for example, a warning, or treatment laser  450  shut off. 
         [0048]    In various embodiments, other safety devices (e.g. position sensors, temperature sensors, etc.) may similarly be incorporated with the surgical waveguide  110  and hand piece  105 . 
         [0049]    One or more or any part thereof of the treatment, IR sensing, or safety techniques described above can be implemented in computer hardware or software, or a combination of both. The methods can be implemented in computer programs using standard programming techniques following the method and figures described herein. Program code is applied to input data to perform the functions described herein and generate output information. The output information is applied to one or more output devices such as a display monitor. Each program may be implemented in a high level procedural or object oriented programming language to communicate with a computer system. However, the programs can be implemented in assembly or machine language, if desired. In any case, the language can be a compiled or interpreted language. Moreover, the program can run on dedicated integrated circuits preprogrammed for that purpose. 
         [0050]    Each such computer program is preferably stored on a storage medium or device (e.g., ROM or magnetic diskette) readable by a general or special purpose programmable computer, for configuring and operating the computer when the storage media or device is read by the computer to perform the procedures described herein. The computer program can also reside in cache or main memory during program execution. The analysis method can also be implemented as a computer-readable storage medium, configured with a computer program, where the storage medium so configured causes a computer to operate in a specific and predefined manner to perform the functions described herein. 
         [0051]    As used herein the term “light” is to be understood to include electromagnetic radiation both within and outside of the visible spectrum, including, for example, ultraviolet and infrared radiation. 
         [0052]    While the invention has been described in connection with the specific embodiments thereof, it will be understood that it is capable of further modification. Furthermore, this application is intended to cover any variations, uses, or adaptations of the invention, including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains, and as fall within the scope of the appended claims. 
         [0053]    It should be appreciated that the particular implementations shown and described herein are examples and are not intended to otherwise limit the scope in any way.