Patent Publication Number: US-8121704-B2

Title: Leakage-resistant tissue treatment apparatus and methods of using same

Description:
FIELD OF THE INVENTION 
     The invention generally relates to apparatus and methods for treating tissue with high frequency energy and, more particularly, relates to treatment apparatus and methods for treating tissue with high frequency energy that include liquid-mediated tissue cooling and leakage control mechanisms for the heat transfer fluid used in the liquid-mediated tissue cooling. 
     BACKGROUND OF THE INVENTION 
     Energy delivery devices that can non-invasively treat tissue are extensively used to therapeutically treat numerous diverse skin conditions. Among other uses, non-invasive energy delivery devices may be used to tighten loose skin to make a patient appear younger, remove skin spots or hair, or kill bacteria. Such non-invasive energy delivery devices emit electromagnetic energy in different regions of the electromagnetic spectrum for tissue treatment. 
     High frequency treatment devices, such as radio-frequency (RF)-based devices, may be used to treat skin tissue non-ablatively and non-invasively by passing high frequency energy through a surface of the skin to underlying tissue, while actively cooling the skin to prevent damage to a region of the tissue near the skin surface. The high frequency energy heats the tissue beneath the cooled region to a temperature sufficient to denature collagen, which causes the collagen to contract and shrink and, thereby, tighten the treated tissue. Treatment with high frequency energy also causes a mild inflammation. The inflammatory response of the treated tissue causes new collagen to be generated over time (between three days and six months following treatment), which results in further tissue contraction. 
     Modern high frequency treatment devices employ a handpiece, a treatment tip coupled with the handpiece, and a high frequency generator connected with electrodes in the treatment tip by the handpiece. Conventional electrodes consist of a pattern of metallic features carried on a flexible electrically insulating substrate, such as a thin film of polyimide. The substrate contacts the patient&#39;s skin surface during treatment. The temperature of the treatment tip, which is measured by temperature sensors carried on the treatment tip, is correlated with the temperature of the patient&#39;s skin. 
     Treatment tips are frequently intended for single patient use and, therefore, non-reusable. As a result, the disposable treatment tips are designed to be temporarily installed onto the nose of the reusable handpiece. Upon installation onto the handpiece nose, one or more latches lock the treatment tip in the proper position. After the conclusion of the patient treatment, the doctor or treatment technician unlatches the treatment tip and removes it from the handpiece to be discarded. 
     The treatment tip is cooled with a heat transfer fluid for the purpose of cooling the tissue region proximate to the skin surface that is in a contacting relationship with the substrate carrying the one or more electrodes. The superficial cooling protects outer layers of tissue and regulates the treatment depth. One approach for supplying heat transfer fluid to the treatment tip is a closed-loop cooling system that circulates the heat transfer fluid through the treatment tip. When the treatment tip and handpiece are united together, pathways are established between the treatment tip and handpiece for the transfer of fluid to and the draining of fluid from the treatment tip. 
     When the treatment tip is initially united with the handpiece, the pathways from the handpiece to the treatment tip should be free of leakage. The separate pathways permit the heat transfer fluid to flow from the handpiece to the treatment tip and then return from the treatment tip back to the handpiece after circulation through the treatment tip. When the treatment tip is separated from the handpiece following a patient treatment, the continuity of the pathways is severed. The portions of the severed pathways in the handpiece are unblocked, which may permit the heat transfer fluid to leak or drip from the handpiece. In addition, the portions of the severed pathways in the treatment tip are also unblocked, which may cause heat transfer fluid to leak from the treatment tip before disposal. 
     What is needed, therefore, are apparatus and methods for controlling the escape of heat transfer fluid from the treatment tip when the treatment tip is removed from the handpiece. 
     SUMMARY OF THE INVENTION 
     The invention is generally directed to treatment apparatus and methods that deliver high frequency energy to tissue underlying a skin surface during non-invasive tissue treatments. The treatment apparatus delivers a fluid, such as a heat transfer fluid, from a handpiece to a treatment tip. The fluid may be returned from the treatment tip to the handpiece to define closed loop circulation. 
     In one embodiment, the apparatus includes a treatment tip configured to be removably coupled with a handpiece and a conduit inside the handpiece. The treatment tip includes an electrode configured to deliver the high frequency energy to a region of the tissue, a channel for circulating heat transfer fluid proximate to the electrode, and an inlet passage to the channel. The conduit includes a tubular sidewall with a lumen configured to be coupled with the inlet passage for transferring the heat transfer fluid from the handpiece to the inlet passage of the treatment tip. A septum covers the inlet passage and, when the treatment tip is coupled to the handpiece, is configured to be pierced by the conduit to define an opening for coupling the first conduit with the inlet passage. When the treatment tip is removed from the handpiece to decouple the conduit from the inlet passage, the septum substantially seals the first opening. 
     In another embodiment, a method is provided for operating a tissue treatment apparatus to treat tissue located beneath a skin surface with high frequency energy delivered from an electrode. The method includes attaching a treatment tip carrying the electrode to a handpiece to establish a fluid connection between a lumen of a conduit in the handpiece and an inlet passage in the treatment tip. When attaching the treatment tip to the handpiece to establish the fluid connection, the conduit pierces a septum to define an opening permitting the conduit to be coupled in fluid communication with the inlet passage. The method further includes transferring heat transfer fluid through the lumen of the conduit to the treatment tip, and delivering the high frequency energy from the electrode to a region of the tissue to perform a tissue treatment. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagrammatic view of a treatment system with a handpiece, a treatment tip, and a console in accordance with an embodiment of the invention 
         FIG. 2  is a diagrammatic view of the handpiece, treatment tip, and console of  FIG. 1  showing a closed-loop cooling system of the treatment system. 
         FIG. 3  is a rear view of the assembled treatment tip taken generally along line  3 - 3  in  FIG. 2  showing the electrode and temperature sensors. 
         FIG. 4  is an exploded view of the treatment tip of  FIG. 2  in which the treatment electrode is shown in an unfolded condition. 
         FIG. 5  is a front perspective view of a manifold body located inside the treatment tip of  FIG. 4 . 
         FIG. 6  is a rear perspective view of the manifold body of  FIG. 5 . 
         FIG. 7  is an enlarged cross-sectional view of a circled region in  FIG. 2 . 
         FIG. 8  is a perspective view of the handpiece and treatment tip of  FIG. 2  in which the treatment tip is shown separated from the handpiece. 
         FIG. 9  is an enlarged cross-sectional view similar to  FIG. 7  in which the treatment tip is shown separated from the handpiece. 
     
    
    
     DETAILED DESCRIPTION 
     With reference to  FIGS. 1-4 , a treatment apparatus  10  includes a handpiece  12 , a treatment tip  14  coupled in a removable and releasable manner with the handpiece  12 , a console generally indicated by reference numeral  16 , and a system controller  18 . The system controller  18 , which is incorporated into the console  16 , controls the global operation of the different individual components of the treatment apparatus  10 . Under the control of the system controller  18  and an operator&#39;s interaction with the system controller  18  at the console  16 , the treatment apparatus  10  is adapted to selectively deliver electromagnetic energy in a high frequency band of the electromagnetic spectrum, such as the radiofrequency (RF) band to non-invasively heat a region of a patient&#39;s tissue to a targeted temperature range. The elevation in temperature may produce a desired treatment, such as removing or reducing wrinkles and otherwise tightening the skin to thereby improve the appearance of a patient  20  receiving the treatment. In alternative embodiments, the treatment apparatus  10  may be configured to deliver energy in the infrared band, microwave band, or another high frequency band of the electromagnetic spectrum, rather than energy in the RF band, to the patient&#39;s tissue. 
     The treatment tip  14  carries an energy delivery member in the representative form of a treatment electrode  22 . The treatment electrode  22  is electrically coupled by a set of conductors  21  with a generator  38  configured to generate the electromagnetic energy used in the patient&#39;s treatment. In a representative embodiment, the treatment electrode  22  may have the form of a region  26  of an electrical conductor carried on an electrically-insulating substrate  28  composed of a dielectric material. In one embodiment, the substrate  28  may comprise a thin flexible base polymer film carrying the conductor region  26  and thin conductive (e.g., copper) traces or leads  24  on the substrate  28  that electrically couple the conductor region  26  with contact pads  25 . The base polymer film may be, for example, polyimide or another material with a relatively high electrical resistivity and a relatively high thermal conductivity. The conductive leads  24  may contain copper or another material with a relatively high electrical conductivity. Instead of the representative solid conductor region  26 , the conductor region  26  of treatment electrode  22  may include voids or holes unfilled by the conductor to provide a perforated appearance or, alternatively, may be segmented into plural individual electrodes that can be individually powered by the generator  38 . 
     In one specific embodiment, the treatment electrode  22  may comprise a flex circuit in which the substrate  28  consists of a base polymer film and the conductor region  26  consists of a patterned conductive (i.e., copper) foil laminated to the base polymer film. In another specific embodiment, the treatment electrode  22  may comprise a flex circuit in which the conductor region  26  consists of patterned conductive (i.e., copper) metallization layers directly deposited the base polymer film by, for example, a vacuum deposition technique, such as sputter deposition. In each instance, the base polymer film constituting substrate  28  may be replaced by another non-conductive dielectric material and the conductive metallization layers or foil constituting the conductor region  26  may contain copper. Flex circuits, which are commonly used for flexible and high-density electronic interconnection applications, have a conventional construction understood by a person having ordinary skill in the art. 
     The substrate  28  includes a contact side  32  that is placed into contact with the skin surface of the patient  20  during treatment and a non-contact side  34  that is opposite to the contact side  32 . The conductor region  26  of the treatment electrode  22  is physically carried on non-contact side  34  of the substrate  28 . In the representative arrangement, the substrate  28  is interposed between the conductor region  26  and the treated tissue such that, during the non-invasive tissue treatment, electromagnetic energy is transmitted from the conductor region  26  through the thickness of the substrate  28  by capacitively coupling with the tissue of the patient  20 . 
     When the treatment tip  14  is physically engaged with the handpiece  12 , the contact pads  25  face toward the handpiece  12  and are electrically coupled with electrical contacts (not shown), such as pogo pin contacts, inside the handpiece  12 . These electrical contacts are electrically coupled with insulated and shielded conductors  21  that extend exteriorly of the handpiece  12  to a generator  38  at the console  16 . The generator  38 , which has the form of a high frequency power supply, is equipped with an electrical circuit (not shown) operative to generate high frequency electrical current, typically in the radio-frequency (RF) region of the electromagnetic spectrum. The operating frequency of generator  38  may advantageously be in the range of several hundred kHz to about twenty (20) MHz to impart a therapeutic effect to treat target tissue beneath a patient&#39;s skin surface. The circuit in the generator  38  converts a line voltage into drive signals having an energy content and duty cycle appropriate for the amount of power and the mode of operation that have been selected by the clinician, as understood by a person having ordinary skill in the art. In one embodiment, the generator  38  is a 400-watt, 6.78 MHz high frequency generator. 
     A non-therapeutic passive or return electrode  40 , which is electrically coupled with the generator  38 , is physically attached to a site on the body surface of the patient  20 , such as the patient&#39;s lower back. During treatment, high frequency current flows from the treatment electrode  22  through the treated tissue and the intervening bulk of the patient  20  to the return electrode  40  and then through conductors inside a return cable  41  to define a closed circuit or current path  42 . Because of the relatively large surface area of the return electrode  40  in contact with the patient  20 , the current density flowing from the patient  20  to the return electrode  40  is relatively low in comparison with the current density flowing from the treatment electrode  22  to the patient  20 . As a result, the return electrode  40  is non-therapeutic because negligible heating is produced at its attachment site to the patient  20 . High frequency electrical current flowing between the treatment electrode  22  and the patient  20  is maximized at the skin surface and underlying tissue region adjacent to the treatment electrode  22  and, therefore, delivers a therapeutic effect to the tissue region near the treatment site. 
     As best shown in  FIG. 3 , the treatment tip  14  includes temperature sensors  44 , such as thermistors or thermocouples, that are located on the non-contact side  34  of the substrate  28  that is not in contact with the patient&#39;s skin surface. Typically, the temperature sensors  44  are arranged about the perimeter of the conductor region  26  of the treatment electrode  22 . Temperature sensors  44  are constructed to detect the temperature of the treatment electrode  22  and/or treatment tip  14 , which may be representative of the temperature of the treated tissue. Each of the temperature sensors  44  is electrically coupled by conductive leads  46  with one or more of the contact pads  25 , which are used to supply direct current (DC) voltages from the system controller  18  through the shielded conductors  21  to the temperature sensors  44 . 
     With continued reference to  FIGS. 1-4 , the system controller  18  regulates the power delivered from the generator  38  to the treatment electrode  22  and otherwise controls and supervises the operational parameters of the treatment apparatus  10 . The system controller  18  may include user input devices to, for example, adjust the applied voltage level of generator  38 . The system controller  18  includes a processor, which may be any suitable conventional microprocessor, microcontroller or digital signal processor, executing software to implement control algorithms for the operation of the generator  38 . System controller  18 , which may also include a nonvolatile memory (not shown) containing programmed instructions for the processor, may be optionally integrated into the generator  38 . System controller  18  may also communicate, for example, with a nonvolatile memory carried by the handpiece  12  or by the treatment tip  14 . The system controller  18  also includes circuitry for supplying the DC voltages and circuitry that relates changes in the DC voltages to the temperature detected by the temperature sensors  44 , as well as temperature sensors  90  and  88 . 
     With specific reference to  FIG. 8 , the handpiece  12  is constructed from a body  48  and a cover  50  that is assembled with conventional fasteners with the body  48 . The assembled handpiece  12  has a smoothly contoured shape suitable for manipulation by a clinician to maneuver the treatment tip  14  and treatment electrode  22  to a location proximate to the skin surface and, typically, in a contacting relationship with the skin surface. An activation button  36 , which is accessible to the clinician from the exterior of the handpiece  12 , is depressed for closing a switch that energizes the treatment electrode  22  and, thereby, delivers high frequency energy over a short delivery cycle to treat the target tissue. Releasing the activation button  36  opens the switch to discontinue the delivery of high frequency energy to the patient&#39;s skin surface and underlying tissue. After the treatment of one site is concluded, the handpiece  12  is manipulated to position the treatment tip  14  near a different site on the skin surface for another delivery cycle of high frequency energy delivery to the patient&#39;s tissue. 
     With reference to  FIGS. 4-6 , the treatment tip  14  includes a rigid outer shell  52 , a rear cover  54  that is coupled with an open rearward end of the outer shell  52 , and a manifold body  55  disposed inside an enclosure or housing inside the outer shell  52 . A portion of the substrate  28  overlying the conductor region  26  of the treatment electrode  22  is exposed through a window  56  defined in a forward open end of the outer shell  52 . The substrate  28  is wrapped or folded about the manifold body  55 . A hooked prong  58  ( FIGS. 7 ,  9 ), which projects from the rear cover  54 , is captured by a lip on the handpiece  12  during installation of the treatment tip  14 . 
     As best shown in  FIGS. 4 and 5 , the manifold body  55 , which may be formed from an injection molded polymer resin, includes a front section  60 , a stem  62  projecting rearwardly from the front section  60 , and ribs  64  on the stem  62  used to position the manifold body  55  inside the outer shell  52 . The front section  60  of the manifold body  55  includes a channel  66  that, in the assembly constituting treatment tip  14 , underlines the conductor region  26  of the treatment electrode  22 . The shape of the front section  60  corresponds with the shape of the window  56  in the outer shell  52 . The substrate  28  of the treatment electrode  22  is bonded with a rim  68  of the manifold body  55  to provide a fluid seal that confines heat transfer fluid  94  flowing in the channel  66 . The area inside the rim  68  is approximately equal to the area of the conductor region  26  of treatment electrode  22 . Channel  66  includes convolutions that are configured to optimize the residence time of the heat transfer fluid  94  in channel  66 , which may in turn optimize the heat transfer between the heat transfer fluid  94  and the treatment electrode  22 . 
     An inlet bore or passage  70  and an outlet bore or passage  72  extend through the stem  62  of the manifold body  55 . The inlet passage  70  and outlet passage  72  are rearwardly accessible through an oval-shaped slot  74  defined in the rear cover  54 . The inlet passage  70  intersects the channel  66  at an inlet  76  to the channel  66  and the outlet passage  72  intersects the channel  66  at an outlet  78  from the channel  66 . The channel  66  is split into two channel sections  80 ,  82  so that fluid flow in the channel  66  diverges away in two separate streams from the inlet  76  and converges together to flow into the outlet  78 . Fluid pressure causes the heat transfer fluid  94  to flow from the inlet  76  through the two channel sections  80 ,  82  to the outlet  78  and into the outlet passage  72 . 
     With reference to FIGS.  2  and  4 - 6 , fluid connections are established with the inlet passage  70  and the outlet passage  72  to establish the closed circulation loop and permit fluid flow to the channel  66  in the manifold body  55  when the treatment tip  14  is mated with the handpiece  12 . Specifically, the inlet passage  70  to the manifold body  55  is coupled with a supply line  86  in the form of an inlet conduit or tube. The outlet passage  72  from the manifold body  55  is coupled with a return line  84  in the form of a fluid conduit or tube. The return line  84  and the supply lines  86  extend out of the handpiece  12  and are routed to the console  16 . Structure facilitating the establishment of fluid-tight connections is described in detail hereinbelow. 
     With reference to  FIG. 2 , the treatment apparatus  10  is equipped with a closed loop cooling system that includes the manifold body  55  located inside the treatment tip  14 . The closed loop cooling system further includes a reservoir  96  holding a volume of a heat transfer fluid  94  and a pump  98 , which may be a diaphragm pump, that continuously pumps a stream of the heat transfer fluid  94  from an outlet of the reservoir  96  through the supply line  86  to the manifold body  55  in the treatment tip  14 . The manifold body  55  is coupled in fluid communication with the reservoir  96  by the return line  84 . The return line  84  conveys the heat transfer fluid  94  from the treatment tip  14  back to the reservoir  96  to complete the circulation loop. 
     Heat generated in the treatment tip  14  by energy delivery from the treatment electrode  22  and heat transferred from the patient&#39;s skin and an underlying depth of heated tissue is conducted through the substrate  28  and treatment electrode  22 . The heat is absorbed by the circulating heat transfer fluid  94  in the channel  66  of the manifold body  55 , which lowers the temperature of the treatment electrode  22  and substrate  28  and, thereby, cools the patient&#39;s skin and the underlying depth of heated tissue. The contact cooling, at the least, assists in regulating the depth over which the tissue is heated to a therapeutic temperature by the delivered electromagnetic energy. 
     The heat transfer fluid  94  stored in the reservoir  96  is chilled by a separate circulation loop  101  that pumps heat transfer fluid  94  from the reservoir  96  through separate supply and return lines to a coldplate  102 . A pump  100 , which may be a centrifugal pump, pumps the heat transfer fluid  94  under pressure from the reservoir  96  to the coldplate  102 . In a representative embodiment, the coldplate  102  may be a liquid-to-air heat exchanger that includes a liquid heat sink with a channel (not shown) for circulating the heat transfer fluid  94 , a thermoelectric module (not shown), and an air-cooled heat sink (not shown). 
     A temperature controller  104  inside the console  16  is electrically coupled with the coldplate  102  and is also electrically coupled with the system controller  18 . The system controller  18 , which is electrically coupled with a temperature sensor  88  used to measure the heat transfer fluid temperature in the reservoir  96 , supplies temperature control signals to the temperature controller  104  in response to the measured heat transfer fluid temperature. Under the feedback control, the temperature controller  104  reacts to the control temperature communicated from the temperature sensor  88  to control the operation of the coldplate  102  and, thereby, regulate the temperature of the heat transfer fluid  94  in the reservoir  96 . 
     With reference to FIGS.  4  and  7 - 9 , the handpiece  12  includes a pair of rigid tubes  110 ,  112  with respective tips  114 ,  116  that project outwardly from a flow part  118 . The flow part  118  conceals the portions of the rigid tubes  110 ,  112  located inside the handpiece  12 . The rigid tubes  110 ,  112  extend through respective openings penetrating through the flow part  118  and have lumens  111 ,  113  that are respectively coupled inside the handpiece  12  with a pair of flexible conduits or lines  120 ,  122 . 
     A flow control valve in the representative form of a pinch valve, generally indicated by reference numeral  124 , is located inside the handpiece  12 . The pinch valve  124  includes a pin  126 , a movable member in the form of a ram or plunger  128  that is mechanically coupled with the pin  126  to form an assembly, a stationary member in the form of an anvil body  130  on the flow part  118 , and an actuator in the representative form of a coil spring  132  that is configured to apply a biasing force to the plunger  128 . A forward end  125  of the pin  126  is centrally located between the tips  114 ,  116  of the rigid tubes  110 ,  112  and, inside the handpiece  12 , the remainder of the pin  126  is centrally located between the rigid tubes  110 ,  112  and the flexible lines  120 ,  122 . The anvil body  130  includes a spaced-apart pair of contoured contact or pinch surfaces  134 ,  136 . One of the flexible lines  120  is located between a contact or pinch surface  138  of plunger  128  and pinch surface  134  on the anvil body  130 . The other flexible line  122  is located between a contact or pinch surface  140  of plunger  128  and pinch surface  136  on the anvil body  130 . 
     The pinch valve  124  has a first closed position ( FIGS. 8 ,  9 ) in which the flexible lines  120 ,  122  are respectively compressed between the pinch surfaces  134 ,  136  on anvil body  130  and the pinch surfaces  138 ,  140  on plunger  128 . The material forming the flexible lines  120 ,  122  is sufficiently compliant to the compressive force or pressure from the pinching action so that the respective sidewalls collapse inwardly to totally or partially occlude a lumen  142  of flexible line  120  and a lumen  144  of flexible line  122 . In a closed position, heat transfer fluid  94  is substantially or completely occluded by the pinch valve  124  from flowing through the flexible lines  120 ,  122  to an extent sufficient to reduce or eliminate fluid leakage from the outlets of the rigid tubes  110 ,  112 . The closed position occurs when the treatment tip  14  is removed from the handpiece  12 . 
     The rigid tubes  110 ,  112 , which are relatively short in comparison with the flexible lines  120 ,  122 , may be formed from a stainless steel. In contrast, the flexible lines  120 ,  122  are formed from a polymer or an elastomeric material, like a silicone rubber, that is significantly more flexible (has a greater ability to bend) than the material forming the rigid tubes  110 ,  112 . In other words, the flexible lines  120 ,  122  are formed from a material having a significantly lower shear modulus or modulus of rigidity than a material forming the rigid tubes  110 ,  112 . 
     The flexible lines  120 ,  122  distort slightly to permit the ends of the flexible lines  120 ,  122  to be slipped over respective lengths of the rigid tubes  110 ,  112  and grip the rearward ends of the rigid tubes  110 ,  112  after installation to provide a fluid-tight seal. Flexible line  120  has a tubular sidewall  121  composed of a material with sufficient flexibility to at least partially occlude the enclosed lumen  142  by reducing the cross-sectional area for fluid flow when a compressive force is applied between pinch surface  138  of plunger  128  and pinch surface  134  on the anvil body  130  of the pinch valve  124 . The occlusion, which controls the flow of fluid through the lumen  142 , causes deformation that at least partially collapses the lumen  142 . Similarly, flexible line  122  has a tubular sidewall  123  composed of a material with sufficient flexibility to at least partially occlude the enclosed lumen  144  by reducing the cross-sectional area for fluid flow when a compressive force is applied between pinch surface  140  of plunger  128  and pinch surface  136  on the anvil body  130  of the pinch valve  124 . The occlusion, which controls the flow of fluid through the lumen  144 , causes deformation that at least partially collapses the lumen  144 . The deformation of the tubular sidewalls  121 ,  123  is primarily elastic in that the tubular sidewalls  121 ,  123  return to substantially their original shape and cross-sectional area when the compressive force is removed. 
     In the closed position, respective columns of residual heat transfer fluid  94  may remain inside the rigid tubes  110 ,  112 , as well as inside the portion of the flexible lines  120 ,  122  between the pinch surfaces  134 ,  136 ,  138 ,  140  and the rigid tubes  110 ,  112 . Although not wishing to be bound by theory, the columns may remain static and resident inside the handpiece  12  until another treatment tip  14  is installed, which implies that the effective flow rate is zero milliliters per minute. 
     The pinch valve  124  has an open position ( FIGS. 4 ,  7 ) in which the pinch surfaces  138 ,  140  on plunger  128  are separated from the pinch surfaces  134 ,  136  on anvil body  130  so that the flexible lines  120 ,  122  are not compressed therebetween. In the open position, heat transfer fluid  94  is permitted to flow at a given flow rate through the lumen  142  of flexible line  120  to the manifold body  55  inside the treatment tip  14  and to flow through the lumen  144  of flexible line  122  out of the manifold body  55 . The second position is created when the treatment tip  14  is installed on the nose of the handpiece  12 . When the compressive force or pressure applied by the pinch surfaces  134 ,  136 ,  138 ,  140  is removed from the flexible lines  120 ,  122 , the sidewalls of the flexible lines  120 ,  122  recover approximately to their initial non-compressed state and provide a given flow rate of the heat transfer fluid  94  to the treatment tip  14 . 
     The inlet passage  70  in the stem  62  of the manifold body  55  has a tubular section  152  truncated to terminate at an open end. Similarly, the outlet passage  72  in the stem  62  of the manifold body  55  has a tubular section  154  terminating at another end. The tubular sections  152 ,  154  are raised above the surrounding portions of the manifold body  55  and project toward the handpiece  12  when the treatment tip  14  is installed to establish a fluid interface with the handpiece  12 . 
     The tubular sections  152 ,  154  intersect to define a central activation arm  146 . A contact block  145  is located on an opposite side of a septum  150  from the activation arm  146 . The contact block  145  and activation arm  146  participate in providing the open position when the treatment tip  14  is installed in the nose of the handpiece  12 , as depicted in  FIGS. 4 and 7 . Specifically, the activation arm  146  and contact block  145 , which are self-aligned, are also aligned with the pin  126  of the pinch valve  124 . During installation to mate the treatment tip  14  with the handpiece  12 , the contact block  145  contacts a portion of the pin  126 . The activation arm  146  prevents the septum  150  from deflecting as a reinforcement force is applied by the pin  126  to the contact block  145 . The pin  126  and the plunger  128  are pushed by the activation arm  146  and contact block  145  in a direction away from the treatment tip  14  and against the biasing force applied by the coil spring  132  to the plunger  128  that resists motion toward the open position. The coil spring  132  compresses so as to store biasing energy for use in applying a force urging the pinch valve  124  to re-establish the first closed position ( FIGS. 8 ,  9 ). 
     The coil spring  132  must apply a spring force to the plunger  128  that is sufficient to compress the flexible lines  120 ,  122  and place the pinch valve  124  in its closed position. However, the coil spring  132  must readily yield to permit installation of the treatment tip  14  and establish the open position of pinch valve  124 . Hence, the properties of the coil spring  132  should be selected to apply an appropriate spring force to the plunger  128 . 
     The flexible lines  120 ,  122  isolate the heat transfer fluid  94  inside the closed-loop cooling from the components of the pinch valve  124 , which prevents contact between the components and the heat transfer fluid  94 . The tubing constituting flexible lines  120 ,  122  is always imposed between the heat transfer fluid  94  and the components of the pinch valve  124 , which may be beneficial, for example, if contact with the heat transfer fluid  94  is capable of corroding the components of the pinch valve  124 . This benefit means that the materials for the components of the pinch valve  124  are not constrained to be corrosion resistant to the heat transfer fluid  94  as these components are not wetted by the heat transfer fluid  94 . Fluid transfer can be effectively controlled by the pinch valve  124  without concerns raised by fluid wetting of the valve components. 
     The septum  150 , which is best shown in  FIGS. 4 and 9 , covers the open end  151  of the inlet passage  70  and the open end  153  of the outlet passage  72 . During installation, the tips  114 ,  116  of the rigid tubes  110 ,  112  apply a force that is substantially perpendicular to the plane of the septum  150 . The applied force pierces the septum  150  to define openings  115 ,  117  that place the lumens  111 ,  113  of the rigid tubes  110 ,  112  in fluid communication with the inlet and outlet passages  70 ,  72 , respectively. These temporary fluid connections, which are formed when the treatment tip  14  is attached to the handpiece  12 , complete the closed circulation loop. When the treatment tip  14  is separated from the handpiece  12 , the septum  150  heals to close or substantially close the openings  115 ,  117  so that residual heat transfer fluid  94  remaining in the detached treatment tip  14  is blocked from escape. 
     When the treatment tip  14  is coupled with the handpiece  12 , the tip  114  of the rigid tube  110  protrudes through the opening  115  in the septum  150  and projects into an enlarged region at the entrance to the inlet passage  72 . Similarly, the tip  116  of the rigid tube  112  protrudes through the opening  117  in the septum  150  and projects into an enlarged region at the entrance to the outlet passage  70 . The material of septum  150  about the openings  115 ,  117  grips the exterior of the tips  114 ,  116  so that fluid-tight connections are established. 
     In one embodiment, the septum  150  is a thin membrane composed of an elastomeric material characterized by properties that permit the tips  114 ,  116  of the rigid tubes  110 ,  112  to pierce the septum  150  and, upon withdrawal of the tips  114 ,  116 , permit the membrane to heal or close the openings  115 ,  117  so that residual heat transfer fluid  94  is retained in the treatment tip  14 . Specifically, the elastomeric material, when pierced at spaced apart locations by the tips  114 ,  116  of the rigid tubes  110 ,  112 , near the edges of openings  115 ,  117  compresses slightly and grips about the outer diameter of each of the rigid tubes  110 ,  112  with a radial reaction force. When the tips  114 ,  116  of the rigid tubes  110 ,  112  are withdrawn, the compressed elastomeric material forces the openings  115 ,  117  to close. Starter openings  156 ,  158  are provided in the septum  150  at the approximate locations at which the septum  150  is pierced by the tips  114 ,  116  of the rigid tubes  110 ,  112 . The starter openings  156 ,  158  function to permit the tips  114 ,  116  to initiate penetration through the septum  150  and the formation of openings  115 ,  117  with a reduced likelihood of either tearing or ripping the septum  150 . 
     In another embodiment, the septum  150  is composed of an elastomeric membrane that is either adhesively bonded with the rear cover  54  or, when the rear cover  54  is integrally formed, with the rear cover  54  by an overmolding process. In yet another embodiment, the septum  150  may be formed from a material having a durometer of about 30 Shore A, as measured by the ASTM D2240 type A scale, and a thickness in a range of about 25 mils to about 35 mils. These combinations of durometer (i.e., the material&#39;s resistance to permanent indentation) and thicknesses is believed adequate to impart tear and rip resistance when the tips  114 ,  116  pierce the septum  150 . Other representative materials for septum  150  include, but are not limited to, thermoplastic elastomers (TPEs), such as the DYNAFLEX® family of TPE compounds commercially available from GLS Corporation (McHenry, Ill.). 
     While the invention has been illustrated by a description of various embodiments and while these embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Thus, the invention in its broader aspects is therefore not limited to the specific details, representative apparatus and method, and illustrative example shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicant&#39;s general inventive concept.