LASER HANDPIECE HAVING ZERO TIME POSITIONING SYSTEM

Abstract: A laser ablation device is provided having a zero time positioning system. The laser ablation device includes a handpiece (14) having a sensor (28) adjacent the distal end of a tube (24) from which an optical fiber (12) exits the handpiece. This sensor (28) senses the fiber's position within the tube (24) by detecting a signal such as the red light which emanates from the fiber prior to firing. Upon detection of the red signal, the sensor (28) sends feedback information to a control module (22) which can suspend further advancement of the fiber. The sensor could include an infrared detector, a photo-detector, or a heat/temperature sensor. In an alternate embodiment of a zero time positioning system configured for closed surgery, a sensor (28) is provided for detecting a marker on the fiber sheath as the fiber sheath moves relative to the handpiece (14). Upon detection of the marker, the sensor sends feedback information to the control module which can suspend further advancement of the fiber.

Description: LASER HANDPIECE HAVING ZERO TIME POSITIONING SYSTEM BACKGROUND Technical Field The present disclosure relates generally to a laser ablation device for surgical use More specifically, the present disclosure relates to a laser ablation handpiece having a zero time positioning system designed to provide an accurate location of the distal end of an optical fiber prior to starting a surgical procedure. Background of the Related Art A variety of procedures and apparatus have been developed to treat cardiovascular disease. For example, minimally invasive surgical procedures such as balloon angioplasty and atherectomy have received extensive investigation and are in wide use In some patients, however, circumstances still require conventional open heal-t bypass surgery to correct or treat advanced cardiovascular disease In some circumstances patients may be too weak to undergo the extensive trauma of bypass surgery or repetitive bypasses may already have proved unsuccessful. An alternative procedure to bypass surgery is transmyocardial revascularization (TMR). TMR is a procedure for producing channels of small diameters within the myocardium, which channels extend into the ventricle Such channels are believed to facilitate delivery of blood directly from the ventricle to oxygen starved areas of the heart TMR is typically used on patients with ischemic heart disease who are not candidates for coronary artery bypass or percutaneous transluminal angioplasty During a conventional procedure, typically dozens of channels are created from the epicardium, through the myocardium and endocardium and into the ventricle, with each channel being of sufficiently small diameter such that the end portions of the channels at the epicardium can be closed by blood clotting The channels are preferably created by employing either a mechanical coring apparatus or an advancing lasing device, such as an optical fiber In the case of the latter, the optical fiber is advanced through a handpiece in proximity to the heart tissue and a laser is fired to transmit laser energy through the fiber to ablate the heart tissue A TMR procedure is generally performed either percutaneously or by exposing the heart via a thoracotomy, i e , an open procedure In the earlier procedure, a laser fiber is navigated through the tortuous arterial pathways to reach a ventricular cavity Laser energy is then transmitted through the laser fiber to create TMR channels within the heart tissue In the latter method, the surgeon places the optical fiber in proximity to the epicardium and subsequently fires the laser to create TMR channels within the heart tissue Before laser energy is transmitted to ablate heart tissue, i e , at time zero, it is desirable for the surgeon to know the location of the distal end of the fiber This location information is useful in letting the surgeon know if the fiber has exited the handpiece and if so, how much fiber has exited the handpiece This information is necessary to prevent premature firing of the laser, i.e., firing the laser before the fiber has exited the handpiece Premature firing could damage the handpiece and other components therein, including the fiber sheath Additionally, if too much fiber exits the handpiece prior to the TMR procedure, heart tissue in proximity to the handpiece may be inadvertently scratched or pierced It is preferred for the surgeon to know the location of the distal end within 0.50 mm for open procedures and 0 25 mm for percutaneous procedures Accordingly, a need exists for a TMR laser ablation device having an accurate zero time positioning system for allowing the surgeon to know the location of the distal end of the fiber prior to initiating the TMR procedure SUMMARY In accordance with the present disclosure, a laser ablation device is provided having a zero time positioning system The laser ablation device includes a handpiece having a sensor adjacent the distal end of a tube from which an optical fiber exits the handpiece This sensor senses the fiber's position within the tube by detecting a signal such as the red light which emanates from the fiber prior to firing Upon detection of the red signal, the sensor sends feedback information to a control module which can suspend further advancement of the fiber The sensor could include an infrared detector, a photodetector, or a heat/temperature sensor In an alternate embodiment of a zero time positioning system configured for closed surgery, a sensor is provided for detecting a marker on the fiber sheath as the fiber sheath moves relative to the handpiece Upon detection of the marker, the sensor sends feedback information to the control module which can suspend further advancement of the fiber The distance from the distal end of the fiber to the marker and the position of the sensor can be arranged such that when the control module suspends advancement of the fiber, the fiber extends slightly beyond the distal end of the articulating tube After time zero, the laser ablation device allows for longitudinal movement of the optical fiber at a controlled rate coordinated with the laser energy generator output to ablate heart tissue BRIEF DESCRIPTION OF THE DRAWINGS Various preferred embodiments are described herein with reference to the drawings FIG 1 is a perspective view of a laser ablation device in accordance with the present disclosure, FIG 2 is a perspective view of a laser ablation control module and optical fiber advancing assembly combined into a single unit. FIG 3 is an enlarged perspective view of the handpiece of the laser ablation device shown in FIG 1 , FIG 4 is an enlarged perspective view with parts separated showing the various components of the handpiece, FIG 4A is an enlarged perspective view of a light-detecting sensor, FIG 5 is an enlarged perspective view of the distal end of the handpiece shown in FIG 1, FIG 6 is an enlarged perspective view of the distal end of the handpiece shown in FIG 1 with the articulating tube being in the articulating position, FIGS 7-12 illustrate a TMR procedure using the laser ablation device of FIG 1, FIG 7 is a side view showing the articulating tube moved into the articulating position, FIG 8 is a side view showing distal translation of an optical fiber through the articulating tube, FIG 8A is an enlarged side view showing the optical fiber exiting the articulating tube, FIG 9 is an enlarged side view in partial cross-section illustrating the fiber piercing the epicardium, FIG 10 is an enlarged side view in partial cross-section illustrating the formation of a channel through heart tissue, FIG 1 1 is an enlarged side view in partial cross-section illustrating the fiber withdrawn from the heart tissue, FIG 12 is an enlarged side view of the handpiece illustrating the fiber retracted back into the articulating tube, FIG 13 is a perspective view of an alternative laser ablation device, FIG 13A is an enlarged perspective view of a marker positioned on an optical fiber of the laser ablation device of FIG 13, FIG 14 is an enlarged perspective view with parts separated showing the various components of the handpiece of the laser ablation dev ice of FIG 13 FIG 15 is an enlarged perspective view of the handpiece of the laser ablation device of FIG. 13, FIG. 16 is an enlarged cross-sectional view showing a sensor within the handpiece detecting a marker positioned on the optical fiber of the laser ablation device of FIG. 13, FIG. 17 is an enlarged perspective view of the distal end of the handpiece shown in FIG 15; FIG. 18 is another alternative laser ablation device, FIG. 19 is an enlarged perspective view of a marker on the optical fiber of the laser ablation device of FIG. 18; FIG. 20 is a cross-sectional view of an alternate handpiece for operating with the laser ablation device shown by FIG l, and FIG. 21 is an enlarged cross-sectional view of the area of detail circled in FIG 20 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the laser ablation device will now be described in detail with reference to the drawings, in which like reference numerals designate identical or corresponding elements. The disclosed embodiment is particularly suited for used in performing transmyocardial revascularization (TMR) Other uses are also contemplated including any procedure wherein an accurate position of the fiber is desirable Referring to FIG 1, a laser ablation device having a zero time positioning system is shown and designated generally by reference numeral 10 Laser ablation device 10 is employed to perform a TMR procedure in accordance with the present disclosure Lasing device 10 is similar to lasing devices disclosed in copending, commonly assigned U.S. Patent Application Serial No 08/648,638 to Pacala et al , filed May 13, 1996, the subject matter of which is incorporated herein by reference Device 10 is capable of advancing a laser ablation member 12, e g., an optical fiber, optical fiber bundle or other laser energy transmission mechanism, through heart tissue while concomitantly outputting laser energy, where the advancement rate is coordinated with the magnitude of laser energy generated and with the pulsing frequency of the laser source It is contemplated that the advancement rate, the magnitude of laser energy generated, and the pulsing frequency of the laser source are automatically controlled by feedback control systems Laser ablation device 10 includes a handpiece 14, an optical fiber advancing mechanism 16, a laser generator 18, a foot operated actuator 20. a control module 22, and a zero time positioning system 27. Handpiece 14 includes an elongated, rigid tube 24 having an articulating tube 26 traverse therethrough. Zero time positioning system 27 includes at least one sensor 28 capable of detecting the red positioning light emanating from fiber 12 prior to firing of the laser generator 18 as further described below. The Max-30 excimer laser manufactured by Medolas of Germany and the Spectranetics CVX-300 excimer laser both transmit a red positioning light through the fiber prior to firing the laser. It is also contemplated that other signals could be utilized to activate the sensor. For example, sound, magnetic, electromagnetic, and chemical. Zero time positioning system 27 further includes circuitry within control module 22 for processing signals transmitted from sensor 28 via a wire 3 1 for determining when fiber 12 has exited articulating tube 26. Sensor 28 could include an infrared detector, a photodetector, or a heat/temperature sensor. It is also contemplated to utilize more than one sensor to position fiber 12 relative to handpiece 14. Laser generator 18 may be either a continuous wave laser or a pulsed, high energy laser, such as, for example, an excimer, C0 2 , Yag or an alexandrite laser. Optical fiber advancing mechanism 16 and laser generator 18 are operably connected to foot actuator 20. Optical fiber advancing mechanism 16 is of the type capable of precisely transmitting longitudinal motion to optical fiber 12 and to suspend advancement of fiber 12 upon detection of the red positioning light by sensor 28. The controlled longitudinal motion can be provided by one or more motors and preferably by one or more stepper motors which can deliver approximately four pounds of pushing force and 1.25 pounds of pull force to a 1.4 mm fiber bundle. After sensor 28 has detected the red positioning light, i.e., after time zero, foot actuator 20 is depressed to transmit laser energy through optical fiber 12 while fiber advancing mechanism 16 contemporaneously advances optical fiber 12 relative to handpiece 14. An electrical signal from foot actuator 20 actuates control module 22 which communicates with fiber advancing mechanism 16. Control module 22 is programmable and controls the motors or other suitable advancing structure in advancing mechanism 16 upon actuation of foot actuator 20. With reference to FIG. 2, control module 22 is shown with a programmable computer 74 having a terminal 76 and a keyboard 78 for storing instructions required to operate advancing mechanism 16. Computer 74 may be programmed to suspend operation of advancing mechanism 16 when sensor 28 has detected the red positioning light and the fiber 12 has advanced a predetermined distance relative to handpiece 14. A toggle switch 35 may be provided on control module 22 to switch from an operation mode to a test mode. In a particular test mode, when foot actuator 20 is acted upon, flexible optical fiber 12 is moved sequentially from a retracted position, to a predetermined extended position, and back to the retracted position. It is contemplated that the predetermined extended position is the desired position of fiber 12 relative to handpiece 14 after sensor 28 has detected the red positioning light. Fiber advancing mechanism 16 is equipped with two limit switches which are set to control the amount of advancement of optical fiber 12 within the heart tissue. Preferably, these limit switches are automatic, however manual switches are also contemplated. Both limit switches are preempted by control module 22 during ablation if control module 22 determines that optical fiber 12 has entered the ventricle. The first limit switch is activated when optical fiber 12 is at a desired retracted position (i.e., a "home" position), wherein the mechanism that is retracting the fiber is caused to stop. Optical fiber 12 is in the retracted position unless foot actuator 20 is depressed or the test mode is activated. The exact retracted position can be selected by means of programming control module 22 or manually setting selector 36 which is a rotatable knob. The second limit switch limits/controls the maximum distance that optical fiber 12 can extend from handpiece 14. This limit switch may cooperatively operate with the zero time positioning system to receive feedback signals for determining the amount of advancement of fiber 12. External selector 36 is provided so that the operator can select the desired maximum extension of the distal end of optical fiber 12 from a distal end 30 of the articulating tube 26. For example, selector 36 is in the form of a rotatable knob that can be set at selectable positions, wherein each position corresponds to a predetermined maximum longitudinal position of optical fiber 12. When the fiber reaches the selected maximum position, the fibers advancement is automatically terminated. It is contemplated that external selector 36 can be controlled automatically to control the amount of maximum extension of optical fiber 12 beyond handpiece 14. By way of example, the operator can select maximum fiber extension positions so that the distal end of fiber 12 extends from the distal end of articulating tube 26 from between about 1.5 mm and about 50 mm, with the ability to select in increments of about 2.5 mm to about 5 mm. The zero time positioning system can send signals to computer 74 to compute the amount of advancement of fiber 12 by taking into consideration the rate of advancement of optical fiber 12 and the amount of extension of fiber 12 beyond the distal end of articulating tube 26 at time zero. The maximum extension position is preferably chosen to be slightly longer than the heart wall thickness for the particular patient such that fiber 12 will penetrate into the patient's ventricle. Once the maximum extended, position is reached, output of laser energy is automatically suspended. With reference to FIGS. 3 and 4, handpiece 14 includes housing 40 formed from molded housing half-sections 40a and 40b. Housing 40 has an elongated body 42 with a conically tapered section 44. Tube 24 traverses through housing 40 and rests against channel 80 formed within conically tapered section 44 of housing half-sections 40a and 40b. Articulating tube 26 which guides optical fiber 12 traverses a portion of tube 24 and is held within tube 24 by washers 82 and 84. Washer 84 includes a proximal end 85 which is press fit to a distal end of inner tube 88 which traverses rigid tube 24. A proximal end of articulating tube 26 is press fit to a distal end 87 of washer 84 for articulating tube 26 to be held within rigid tube 24. A proximal end of tube 24 is press fit within a first cavity 86 of slidable lever 46 as shown by broken line "A". Inner tube 88 traverses a second cavity 90, a channel (not shown) within wall 92 of lever 46 and tube 24. A distal end of inner tube 88 rests against channel 91 formed in housing 40 and flange 81 rests against groove 83 to fix inner tube 88 to housing 40. When lever 46 is moved proximally along slot 89 formed between housing half-sections 40a and 40b, rigid tube 24 is moved proximally over inner tube 88 to cause articulating tube 26 to move into the articulating position as shown by FIGS. 6 and 7. Articulating tube 26 is manufactured from shape memory, alloy. Two ridged surfaces 47 are formed on lever 46 to facilitate grasping and moving of lever 46. With reference to FIGS. 4A-6 and as noted above, at least one sensor 28 of the zero time positioning system 27 is fitted adjacent the distal end of articulating tube 26 and is electrically coupled to magnetic stripe 29 traversing articulating tube 26. Magnetic stripe 29 is coupled to a wire 31 which exits at the proximal end of handpiece 14. The wire 3 1 is connected to circuitry within control module 22 via an adapter 45 as shown by FIG. 3. A flexible support tube 48 surrounds the distal end of sheath 50 covering optical fiber 12 to reduce stress at the proximal end of handpiece 14. An elongated tubular portion 92 of metallic washer 94 is inserted within a distal end of support tube 48 to connect support tube 48 with handpiece 14. Washer 94 is housed within elongated body 42 of housing 40. The operation of the laser ablation device 10 and zero positioning system 27 will become more apparent from a detailed discussion of a TMR procedure in conjunction with FIGS. 7-12. First, as shown by FIG. 7, lever 46 may be moved proximally to advance articulating tube 26 into the articulating position. Advancing mechanism 16 is then actuated by depressing foot actuator 20 to advance optical fiber 12 a predetermined distance beyond the distal end of articulating tube 26 The predetermined distance can be programmed into control module 22 by using selector 36 as discussed above It is preferred that optical fiber 12 is advanced approximately 1.5 mm beyond articulating tube 26 as shown by FIG. 8. Zero positioning system 27 prevents fiber 12 from being advanced more than 1.5 mm by sending at least one feedback signal to control module 22 to suspend operation of advancing mechanism 16. Then at least one feedback signal is generated by sensor 28 after detecting the red positioning light emanating from fiber 12, as shown by FIG. 8 A. By suspending operation of advancing mechanism 16, zero positioning system 27 ensures that the tip of fiber 12 is protruding approximately 1 5 mm at zero time or whatever distance the surgeon programmed control module 22 to suspend operation of advancing mechanism 16 after detection of the red positioning light. After sensor 28 detects the red positioning light and the operation of advancing mechanism 16 is suspended, handpiece 14 is brought in proximity to the epicardium. It is preferred to position the distal end of optical fiber 12 either on the epicardium or to about 0.5 mm from the epicardium prior to firing laser generator 18 to initiate the TMR procedure. An alternate contemplated procedure is to position optical fiber 12 approximately 1.5 mm from the epicardium. With an advancement rate of 1 mm per second and a pulse rate of 30 pulses per second, upon further activation of the advancing mechanism 16, there are approximately 45 laser pulses prior to contact of fiber 12 with the epicardium. It may be desirable to fire laser generator 18 prior to contact of fiber 12 with the epicardium to loosen any debris on fiber 12 or between fiber 12 and the distal end of articulating tube 26 In one method, with reference to FIGS 9 and 10, fiber 12 is brought into contact with epicardium 60 without actuating laser generator 18 so as to mechanically pierce and thus separate the epicardial outer surface to facilitate the formation of a flap to prevent bleeding as shown by FIG. 9. As the tip of fiber 12 penetrates, epicardial and myocardial tissue 64 adjacent to the fiber tip is pushed aside This pushed aside tissue 64 will not be ablated with laser energy since foot actuator 20 has not yet been activated Tissue 64 will substantially return to its natural position following channel formation and act as a cap to reduce bleeding from the channel. With reference to FIG. 10, the surgeon then commences TMR channel formation by depressing foot actuator 20. This initiates operation of laser generator 18 and advancing mechanism 16 to transmit laser energy from the tip of fiber 12 to ablate heart tissue while correspondingly advancing fiber 12 Optical fiber 12 is advanced through the myocardium 62 and endocardium 66 until it reaches its maximum extended position corresponding to a predetermined distance as preset by selector 36 or until its advancement is suspended by control module 22 in response to feedback control signals or other parameters Optical fiber 12 is preferably advanced at a rate of between about 0 5 mm/sec (0.02 in/sec) to about 12.7 mm/sec (0.5 in/sec) with a laser power level of about 10 mJ/mm 2 to about 60 mJ/mm 2 and a pulsing frequency of about 5 Hz to about 100 Hz. Preferably, the optical fiber is advanced at a rate of about 1 0 mm/sec to about 2 0 mm sec with a laser power level of between about 30 ml/mm 2 to about 40 mJ/mm 2 and a pulse frequency of about 50 Hz. In a most preferred embodiment, the rate of advancement of the optical fiber is no greater than the rate of ablation of tissue in order to minimize mechanical tearing by the fiber Alternatively, if some degree of mechanical tearing is desired in addition to laser ablation, the advancing mechanism can be manually set to advance the fiber at a rate greater than the ablation rate. When fiber 12 penetrates slightly into ventricle 68, output of laser energy is suspended and fiber 12 is automatically retracted. Handpiece 14 is then drawn away from the heart wall whereby transmyocardial channel 70 is completed as shown by FIG. 1 1 The epicardial and myocardial tissue 64 which was pushed aside during channel formation acts as a cap to prevent bleeding from channel 70 Slidable lever 46 is then pushed distally for rigid tube 24 to extend over articulating tube 26 as shown by FIG. 12 It is contemplated to provide a rachet mechanism to operatively cooperate with lever 46 to provide a tactile feedback as to the position of articulating tube 26 when lever 46 is translated distally or proximally. It is also contemplated for the surgeon to apply pressure to the epicardium to stop bleeding when the epicardium is not pierced or apply a suture to the epicardium Handpiece 14 is then is moved to another location on epicardium 60 to begin forming another channel. The overall procedure wherein dozens of channels are typically formed can thus be performed much faster as compared to prior an methods, since each channel 70 can be provided with a cap to prevent bleeding and fiber 12 is automatically retracted into articulating tube 26 following the formation of each TMR channel An alternative embodiment of the laser ablation device having a zero time positioning system is shown by FIG 13 and designated generally by reference numeral 100 Laser ablation device 100 includes a handpiece 104, an optical fiber advancing mechanism 106, a laser generator 108, a foot operated actuator (not shown), a control module 1 12, and a zero time positioning system 1 13 Similarly to laser ablation device 10, laser ablation device 100 is capable of accurately positioning laser ablation member 12 a predetermined distance beyond the distal end of a handpiece at zero time and advancing laser ablation member 12 through heart tissue during a TMR procedure. With reference to FIG 14, handpiece 104 includes an elongated, rigid tube 1 14 having an articulating tube 1 16 traverse therethrough and other components similar to handpiece 14 Sensor 1 18 is mounted within handpiece 104 on inner tube 1 10 to detect marker 120, as shown by FIG. 13N on sheath 122 as fiber 12 is advanced relative to handpiece 104 At least one electrical signal is transmitted to control module 1 12 via wire 124 as sensor 1 18 detects marker 120 on sheath 122, as shown by FIG 16 After receiving at least one electrical signal, control module 1 12 can suspend operation of advancing mechanism 106 Preferably, marker 120 is positioned on sheath 122 where upon detection by sensor 1 18 fiber 12 has advanced approximately 1 5 mm beyond the distal end of articulating tube 1 16, as shown by letter "D" in FIG 17 It is contemplated that marker 120 is movable along sheath 122 to change the amount of advancement of fiber 12 from articulating tube 1 16 at time zero. It is further contemplated that sensor 1 18 is inductive for sensing a pattern created by marker 120 to emulate a magnetic Hall effect sensor. In an alternative embodiment, as shown by FIG 18, and designated generally by reference numeral 200 several markers 202, as shown by FIG 19, are spaced apart on sheath 204 and are designed to create different signals as they are detected by a sensor (not shown) within handpiece 210 Each signal is indicative of a different marker 202 for relaying the amount of advancement of fiber 12 beyond the distal end of articulating tube 206 The signals are sent to control module 208 which determines the amount of advancement of fiber 12 With reference to FIGS 20 and 21 , there is shown a handpiece for preferably performing TMR designated generally by reference numeral 300 and having a fiber positioning calibration mechanism 302 Calibration mechanism 302 permits a surgeon to manually calibrate the position of the distal end of handpiece 300 relative to fiber 12 With particular reference to FIG. 21, calibration mechanism 302 includes an inner member 304 having an outer threaded surface 306 and an outer member 308 having an inner threaded bore 3 10 Inner member 304 includes a bore 3 12 configured and dimensioned to matingly engage tubing 3 14 housing fiber 12 therein Tubing 3 14 is preferably made from hard plastics In operation, the surgeon grasps handpiece 300 with one hand and tubing 3 14 with the other hand and rotates inner member 304 within outer member 308 to move tubing 3 14 distally or proximally depending on the direction of rotation As the tubing 3 14 moves counter- clockwise relative to handpiece 300, the distal end of handpiece 300 moves proximally relative to fiber 12. It is preferred that the maximum distance fiber 12 can be exposed by calibration mechanism 302 is 3 mm. It is contemplated that the calibration mechanism 302 or a similar mechanism can be provided at the proximal end of tubing 3 14, such as at or near advancing mechanism 16. It is further contemplated to provide a marking on the distal end of tubing 3 14 to provide a reference point to easily determine the amount of displacement of fiber 12 with respect to handpiece 300. It will be understood that various modifications be made to the embodiments disclosed herein. For example, other types of lasing devices and handpieces could alternatively be used to produce TMR channels utilizing a sensor adjacent a distal end of the handpiece. Therefore, the above description should not be construed as limiting, but merely as exemplifications of preferred embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the disclosure.

Claims: What is Claimed is: 1. A sensing device for determining the position of a fiber, comprising: a fiber transmitting a position signal; a handpiece having a proximal end and a distal end, the fiber located within the handpiece and being advanceable and retractable within the handpiece; and at least one sensor disposed on the handpiece, the sensor determining the position of the fiber within the tube by detecting the position signal. 2. The sensing device of claim 1, wherein the fiber is an optical fiber. 3. The sensing device of claim 2, further comprising a laser generator for transmitting laser energy through the optical fiber, wherein the position signal is a red positioning light emanating from the optical fiber prior to firing the laser generator. 4. The sensing device of claim 2, further comprising: an optical fiber advancing mechanism to advance and retract the optical fiber; a control module coupled to the sensor and the optical fiber advancing mechanism, the control module programmed to suspend further advancement of the optical fiber when the sensor detects the position signal. 5. The sensing device of claim 1 , wherein the sensor is an infrared detector. 6. The sensing device of claim 1, wherein the sensor is a photodetector. 7. The sensing device of claim 1 , wherein the sensor is a heat/temperature sensor. 8. The sensing device of claim 1 , wherein the handpiece includes an articulating tube to guide the fiber and the sensor is disposed on the articulating tube. 9. The sensing device of claim 8, wherein the articulating tube comprises a shape memory alloy such that the articulating tube is curved when extended and substantially straight when retracted. 10 The sensing device of claim 8, further comprising a magnetic stripe traversing the articulating tube and in electrical connection with the sensor; and a control module electrically connected to the magnetic stripe, wherein the control module is programmed to suspend further advancement of the optical fiber when the sensor detects the position signal 1 1 A sensing device for determining the position of a fiber, comprising a fiber having a marker thereon, a handpiece having a proximal end and a distal end, the fiber located within the handpiece and being advanceable and retractable within the handpiece, and at least one sensor disposed on the handpiece, the sensor determining the position of the fiber within the tube by detecting the marker 12. The sensing device of claim 1 1, wherein the sensor is inductive for sensing a pattern created by the marker to emulate a magnetic Hall effect sensor 13. The sensing device of claim 1 1 , wherein a plurality of markers are spaced apart on the fiber, each marker transmitting a unique position signal such that the relative position of the fiber may be determined when the sensor detects the unique position signal 14. A laser handpiece having a zero time positioning system, comprising an optical fiber emanating a position signal, a handpiece, the optical fiber located within the handpiece and being advanceable and retractable within the handpiece, a sensor disposed on the handpiece, the sensor determining the position of the fiber within the tube by detecting the position signal, and a control module coupled to the sensor and programmed to suspend advancement of the optical fiber when the sensor has detected the position signal and the optical fiber has advanced a predetermined distance relative to the handpiece 15 The laser handpiece of claim 14, wherein the position signal is a red positioning light 16. The laser handpiece of claim 14, further comprising a fiber advancing mechanism to advance and retract the optical fiber, the fiber advancing mechanism being coupled to the control module, and wherein the control module includes a programmable computer with a terminal and keyboard for storing instructions to operate the advancing mechanism 17 A laser handpiece having a zero time positioning system, comprising an optical fiber, a handpiece, the optical fiber located within the handpiece and being advanceable and retractable within the handpiece; a control module programmed to suspend advancement of the optical fiber when the optical fiber has advanced a predetermined distance relative to the handpiece, and a first limit switch and second limit switch coupled to the control module, the first and second limit switches set to control the amount of advancement of the optical fiber within a tissue; wherein the first limit switch is set to activate when the optical fiber is at a retracted "home" position and to cause the fiber advancing mechanism to stop, and wherein the second limit switch is set to limits or control the maximum distance the optical fiber can extend from the handpiece and to cause the fiber advancing to stop 18 The laser handpiece of claim 17, wherein the first and second limit switch are automatic switches 19 The laser handpiece of claim 17, wherein the first and second limit switch are manual switches 20 A method of determining the position of a fiber, the method comprising the steps of: providing a fiber which transmits a position signal, providing a handpiece having at least one sensor disposed thereon, advancing and retracting the fiber relative to a handpiece, and sensing the position of the fiber relative to the handpiece by having the sensor detect the position signal 21. A method of determining the position of a fiber, the method comprising the steps of: providing a fiber having at least one marker disposed thereon; providing a handpiece having a sensor disposed thereon; advancing and retracting the fiber relative to a handpiece; and sensing the position of the fiber relative to the handpiece by having the sensor detect the marker. 22. A method of controlling the position of a fiber, the method comprising the steps of: providing a fiber disposed within a handpiece; advancing and retracting the fiber relative to a handpiece; providing a first limit switch and a second limit switch to control the amount of advancement of the optical fiber; programming the first limit switch to be activated when the optical fiber is at a retracted "home" position and to cause the fiber advancing mechanism to stop; and programming the second limit switch to be activated to limit or control the maximum distance the optical fiber can extend from the handpiece and to cause the fiber advancing to stop.

Inventors: PERNA WILLIAM P, SCHNUT ROBERT H, PERNA, WILLIAM, P., SCHNUT, ROBERT, H.
Applicants: BAXTER INT, PERNA WILLIAM P, SCHNUT ROBERT H, BAXTER INTERNATIONAL, INC., PERNA, WILLIAM, P., SCHNUT, ROBERT, H.
Application year: 1999
Main classification: A61B17
IPC codes: A61B17, A61B18, A61B19