ThoraCool™ User Guide
Contents
1. If water is not dripping into the burette check to see if it is running down the wall of the burette Check to ensure the luer lock connection between the Tube Kit and the ThoraCool Probe is not leaking Ensure that the Pump Unit is connected to the PMG TD The pump is not working Pain Management Pump Unit when in Cooled RF Treatment Mode ready pre cooling on post cooling states Ensure the pump head lids are completely closed Open and close both pump lids and try again Check for error messages on the generator Possible error codes include E101 E103 and E106 Follow flow chart for trouble shooting actions No temperature ThoraCool Probe Ensure that all connections are made measurement Cooled RF Connector Cable and ThoraCool Probe to Connector Cable PM1058 Rev 06 09 Page 40 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries Possible Device Trouble Shooting Actions Or Erratic temperature reading Lesion does not reach set temperature after two minutes BMC RF Generator Pain Management Generator ThoraCool Probe PM1058 Rev 06 09 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries Connector Cable to the generator Gen2. Baylis MAEDICAL FOR THORACIC MEDIAL BRANCH NEUROTOMY ThoraCool Pain Management System User Guide The Baylis Medical Logo and ThoraCoo are trademarks or registered trademarks of Baylis Medical Company Inc in the United States of America and or other countries Baylis Medical Company Inc 2009 Patents pending and or issued PM1058 1 Table of Contents le MPQOISZOR GOMLCIA Sap ssetagstatectas cunnetastadeed tdarotansocseteacendedadtncsetenceattadtose teen eeatne 2 2 WATFOGUGUOMN scierie aa e a aaea 2 3 Physics of the ThoraCool Pain Management System ccccceseeeeeeeeeeeeeees 3 4 Benefits of the Pain Management ThoraCool System cccsecceseeeeeeeeeeeeeeeees 7 5 Technical Description of the EQUIDMeN ccccceceececeeeeeeeeeeeeeseeeseeeeseeeeaeeesaees 8 6 Palen SElO CUO tenuis ceneetectets cncecettageney etaade sta ecennhbtaed ete ecuarhiaadett i ecueataade th te 11 fe sDOUMO ISIC OMS oereage EREEREER SESE 12 8 Procedure GuidelneS 5 xcctacaathe teeta bet aie abach rsa ac aaa eet 18 QO JWESIOM F AlAMICleNS Mecstusitestindeasicesinaelehieasienditaadiehieanienstasiiehieaniensatasitehieaaiensitas 30 10 Generator Graphs During Treatment cccccccccsececeeeeceeeceececeeeeeeeeseeseseeesaes 33 diz TROUDIESMOOUNG icenen a a a E E E 37 2 Introduction The ThoraCool Pain Management System in combination with the Baylis Pain Management Generator PMG TD
3. same time Not damaged applicable to E87 Probe may have had poor tissue contact or not fully inserted in introducer Internal error resolved by reboot Turn PMG ON OFF Internal error requires repair Call Clinical Support PM1058 Rev 06 09 Page 45 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries Trouble Shooting Flow Chart Legend Error Persists gt Errors 101 103 and 104 gt Error Clears gt See additional text Loose or improper connections Check all connections Ensure tubing Loose connection Ensure pump PMG connection cable is secure Ensure pump lids are closed Tubing is correctly incorrectly placed within placed within the pump 1 pump head head Pump lids were open Tube kit ear hot incorrectly It TUDI T connected to connecte correctly to probe the probe Damaged Cooled RF E Connector nsure water Cable Occluded Is flowing tube kit through the tube kit and float ball is floating Swap Cooled RF Connector Cable Re prime while squeezing upper and lower jaw of pump head Th Damaged sia tien Probe Internal error requires repair Call Clinical Support PM1058 Rev 06 09 Page 46 of 48 Baylis Medical Com
4. C Ramp Rate 80 C min Time 2 30 minutes These parameters were tested and scrutinized through a series of bench tests and in vivo experiments The experiments were designed to map temperatures in the tissue and in the surrounding neural structures to ensure that heat was applied in a manner suitable for both efficacy and safety during treatment For practical use set the Advanced Settings on the generator as follows Ramp Rate 80 C min Post Treatment Cooling Disable Number of Probes 1 Power Limit 25 Watts Power Limit must be changed in Advanced Settings from 12 W to 25 W for the ThoraCool procedure PM1058 Rev 06 09 Page 32 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries 10 Generator Graphs During Treatment Overview This section shows images of generator screens to explain what a typical procedure looks like compared to an abnormal procedure In this section you will learn e Appearance of a typical procedure graph e Appearance of an abnormal procedure graph The figures in this section represent screens of a Baylis Pain Management Generator Model PMG 115 TD and PMG 230 TD V2 2A Refer to the generator s user manual for complete details The graph on the generator shows the temperature COOLED RF TEMP in yellow and the power POWER
5. Current Current Time Time Direct Current DC Alternate Current AC Figure 1 Direct Current DC and Alternate Current AC signal amplitudes Resistive Heating with DC Electrical conductance is the property of a material that determines the ability of current to flow through it and is based on the availability of loose electrons in the material Resistance is the opposite of conductance Copper wire for instance has high conductance and is a good conductor while rubber has low conductance and is a very poor conductor Because rubber is a poor conductor this means that it is a good resistor In a resistor as current passes through the material energy is used The harder it is to pass current through a material due to lower conductance the more energy is used The energy that is used does not disappear but is converted to a different form of energy often in the form of heat The conversion of electrical energy to thermal energy by passing current through a material with resistance is called resistive heating A good example of resistive heating is an electric toaster The metal filament in the toaster is PM1058 Rev 06 09 Page 3 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries made of nickel and chromium which has an ideal resistance to convert electricity to heat Biological tissue is not
6. 2231 49 6 Haemmerich D Chachati L Wright AS et al Hepatic radiofrequency ablation with internally cooled probes effect of coolant temperature on lesion size IEEE Trans Biomed Eng 2003 50 493 500 TA Lorentzen T A cooled needle electrode for radiofrequency tissue ablation thermodynamic aspects of improved performance compared with conventional needle design Acad Radiol 1996 3 556 63 8 Noe CE Racz GB Radiofrequency In Raj P ed Pain Medicine A Comprehensive Review First ed Mosby 1996 305 8 9 O Connor JL Bloom DA Wiliam T Bovie and electrosurgery Surgery 1996 119 390 6 10 Organ LW Electrophysiologic principles of radiofrequency lesion making Appl Neurophysiol 1976 39 69 76 11 Saberski L Fitzgerald J Ahmad M Cryoneurolysis and Radiofrequency Lesioning In Raj P ed Practical Management of Pain Third ed Mosby 2000 753 67 12 Watanabe l Masaki R Min N et al Cooled tip ablation results in increased radiofrequency power delivery and lesion size in the canine heart importance of catheter tip temperature monitoring for prevention of popping and impedance rise J Interv Card Electrophysiol 2002 6 9 16 13 Wittkampf FH Hauer RN Robles de Medina EO Radiofrequency ablation with a cooled porus electrode catheter abstract J Am Coll Cardiol 1998 11 14 Wong WS VanderBrink BA Riley RE et al Effect of saline irrigation flow rate on temperature profile during cooled radiofrequency ablation J Interv
7. 27 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries 9 After the first lesion is complete remove the probe and introducer from the patient Remove the probe from the introducer and replace it with the stylet This is important as the probe is not designed to penetrate tough connective tissue Re position the c arm for the next level if necessary and repeat steps 2 8 PM1058 Rev 06 09 Page 28 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries Post Procedure Care Discharge Instructions on the day of the procedure Do not drive or operate machinery Do not engage in any strenuous activity Do not soak in the bathtub but a shower is okay Eat a regular diet You may remove bandages the following day You may use an ice pack today and warm moist heat tomorrow if you experience discomfort when the local anesthetic wears off e f you experience fever chills or severe pain accompanied by swelling and redness at the injection site contact your treating physician e If you experience shortness of breath or chest pains go to the nearest emergency room Activity Guidelines e Resume normal activities as tolerated the day after the procedure e Avoid excessive activ
8. 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries 4 Benefits of the Pain Management ThoraCool System Internally Cooled for Greater Power Applications The ThoraCool System electrodes are internally cooled which allows for greater power to be delivered Increasing power enables the creation of large volume spherical lesions When these lesions are positioned appropriately the inherent variability of nerve target location can be overcome in a practical and efficient manner Temperature Control Temperature sensors at the electrode tips allow the RF generator to control the power delivery and the rate of internal electrode cooling In this manner lesion shape and size will remain consistent This is particularly important in an area of the anatomy that contains multiple tissue types near the target structure Note that the temperatures at the electrode tips are reflective of the surface of the cooled electrodes and not the maximum lesion temperature Spherical Lesions The spherical shape of the lesion allows perpendicular oblique or parallel approaches towards the target structure The lesion will form around ridges and within crevices on irregularly shaped surfaces Probe Placement Placement of the ThoraCool probe is straight forward and results in minimal disturbance to the overlying soft tissue Int
9. head Improper positioning of the tubing can pinch the tube and restrict the water flow e Close the lid in order to hold the tubing in place Leave the luer lock caps on the tubing until you are ready to connect the probes so the inner pathway of the tube kit remains sterile PM1058 Rev 06 09 Page 14 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries 4 Fill the burette with sterile water Fill the burette to the 70 mL mark with room temperature sterile water by a injecting through the port in the lid or b removing the lid and pouring the sterile water into the burette a Inject sterile water through the port in the lid e Remove the cap of the burette e Using a sterile syringe fill the burette with 70 ml of sterile water at room temperature b Remove the lid and pour sterile water into the burette e Open the lid by pressing in and up with your thumbs around one of the three petals e Observe proper sterile handling technique while filling the burette do not place the lid of the burette down on a non sterile surface e The fill lines on the burette represent 70 mL and 80 mL respectively e After filling to between the lines snap the lid back into place on the burette e Note that not all burettes have removable lids In this case fill the burette by injecting water through the port in th
10. is indicated for creating RF lesions in nervous tissue to treat patients with thoracic zygapophyseal joint Z joint pain The procedure is known as thoracic z joint radiofrequency neurotomy and ablates the afferent nociceptive nerves Target structures include the medial branches of the dorsal root These nerves are known to be responsible for thoracic z joint mediated pain In this procedure a ThoraCool Pain Management Introducer is placed at the superolateral aspect of the transverse process A ThoraCool Pain Management Probe is inserted through the introducer and into the tissue superior to the superolateral aspect of the transverse process Radiofrequency RF energy is delivered from and concentrated around the electrode The electrode is internally cooled with circulating water RF energy heats the tissue while circulating water moderates the temperature in close proximity to the electrode This combination creates large volume lesions without excessive heating at the electrode Successive lesions are created by repositioning the introducer and electrode in a step wise manner until both medial branches supplying the painful z joint have been disrupted For a list of equipment related to the ThoraCool Pain Management System see Section 5 A physician using this equipment must be familiar with thoracic spine anatomy image guided spine procedures and medial branch block techniques Important Message This guide does not replace the informa
11. through the ThoraCool Probe This is dose JEn achieved via closed loop fluid circuit The closed loop fluid circuit includes a Pain Management Tube Kit and a ThoraCool Probe e The Pain Management Pump comes with e a connector cable which connects it to the ia generator PMG TD for power and speed control a PM1058 Rev 06 09 Page 8 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries Pain Management Cooled RF Connector Cable Model CRX BAY CRP Important features Used to connect ThoraCool Probe to the generator Provides access to the Cooled RF mode in the generator Transmits RF energy from the generator to the probe Transmits signals from the temperature sensor in the probe to the generator ThoraCool Pain Management Kit Model THK 17 75 Including 1xThoraCool Pain Management Probe Model THP 17 75 Important features e One probe is required for a procedure e The probe delivers RF energy creating a spherical lesion centered about the active tip e Sterile water is circulated internally within the electrode during the procedure which cools the electrode The sterile water is contained and does not contact patient tissue e Each probe has a temperature sensor at the distal end of the electrode The temperature sensor measures temperature and provides co
12. tubing is properly placed in the L shaped tubing guides of the Pump Unit and in the correct direction Check to see that burette reservoir has been filled Check to see that the float in the burette is not stuck at the bottom and occluding the flow of water from the burette Check to the see that the Tube Kit is correctly connected to the luer locks on the ThoraCool Probe PM1058 Rev 06 09 Page 39 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries Possible Device Trouble Shooting Actions Ensure that the portion of tubing that is in the pump head is the thick tubing coming out of the bottom port of the burette and NOT the thin tubing coming from the top of the burette Check for leaks or occlusions in tubing and joints of the Tube Kit Ensure that the pump head lid is closed Repeat pump priming by initiating the lesion with the ON OFF button Gently squeeze the upper and lower jaws of the pump head during priming in order to exert additional pressure on the tubing in the pump abnormal noises correct direction One pump head stops Pain Management Pump Unit This is normal The PMG TD stops the pumps during pretreatment cooling so the during Pretreatment generator can identify which pump head the probe is associated with Cooling Water is not dripping Pain Management Tube Kit into the burette
13. used by the body it can interfere with physiological functions causing unwanted effects This is avoided by using a frequency beyond those used by the body Alternating current with a very high frequency in the order of 500 KHz does not affect physiological functions RF Generators in the Market Today Today modern AC generators use a frequency between 400 and 600 kilohertz which is in the radiofrequency RF range and are generally referred to as RF generators RF generators are now equipped with automatic temperature control and impedance monitoring Temperature control allows for effective lesion formation whereas impedance monitoring detects changes in tissue resistance to electric current Impedance monitoring also aids in electrode placement because impedance varies between different tissues Monopolar Electrode Systems Monopolar System Physics In medical applications RF current is delivered to tissue by an electrode usually on the end of a probe or insulated cannula lonic heating of tissue is a function of the current density or current per unit area RF current flows out of the electrode radially and as a result current density progressively decreases away from the electrode This is illustrated in Figure 2 where a circle represents an electrode and arrows represent the current flowing radially from the electrode The current shown by the arrows is denser in areas closer to the electrode Consequently ionic heating is greate
14. using verbal communication as well as equipment to measure heart rate blood oxygen level and blood pressure e As with any minimally invasive technique adhere to sterile procedural practices e Prepare the site with sterile draping to maintain sterility of the lower lumbar and sacral area e The procedure is conducted with the aid of fluoroscopic guidance Precautions should be taken to minimize exposure to radiation e Ensure the patient is comfortable and the appropriate pharmacological pain therapy has been administered This may constitute intravenous sedation oral analgesics or other methods depending on physician and institution preference The patient should be relaxed and able to communicate throughout the procedure General anesthesia should be avoided PM1058 Rev 06 09 Page 21 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries Thoracic Z Joint Neurotomy Procedural Technique A technique for lesioning the medial branch of the thoracic dorsal ramus using the ThoraCool Pain Management System is provided Fluoroscopic images provided courtesy of Dr Nagy Mekhail Cleveland Clinic Dr Robert E Wright Denver Pain Management and Dr Paul Verrills Metro Spinal Clinic Thoracic Z joint Joint Neurotomy Medial Branch Ablation 1 Obtain an anterior posterior A P fluoroscopic image by
15. 06 09 Page 38 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries Troubleshooting during treatment Possible Device Trouble Shooting Actions No Impedance ThoraCool Probe Cooled RF Ensure that all connections are made measurement Connector Cable and Cooled RF Connector Cable to PMG TD Dispersive Electrode ThoraCool Probe to Cooled RF Connector Cable Grounding Pad to PMG TD Check for an error message on the PMG TD Possible error codes include W209 W210 E125 and E126 Follow the Troubleshooting Flowchart provided on subsequent pages of this section for trouble shooting actions Visually inspect the probe dispersive electrode and cable for damage In Treatment Mode ensure the probe is fully inserted into the introducer Ensure that the devices are dry and at room temperature Fluid is not circulating Pump Pain Management Tube Check for an error message on the generator Possible error codes include E101 during ThoraCool Kit ThoraCool Probe and Pain E103 and E106 Follow the Troubleshooting Flowchart provided on subsequent Treatment Mode Management Generator pages of this section for trouble shooting actions Follow the fluid pathway along the tubing and probes to see if it is pinched or kinked For example if clamps are used to hold the tubing they should not pinch it Check to see that the
16. Card Electrophysiol 2000 4 321 6 PM1058 Rev 06 09 Page 48 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries
17. Cool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries LCD Text Message A High Impedance Detected Check probe and cable connections Possible poor tissue contact Probe s or cable s may be defective A Low Impedance Detected Possible short circuit between electrodes or damaged introducer insulation A High Impedance Detected Check probe cable and dispersive return electrode connections Possible poor tissue contact Probe or cable may be defective A Low Impedance Detected Possible short circuit between electrodes or damaged introducer insulation PM1058 Rev 06 09 Page 44 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries Loose connections Trouble Shooting Flow Chart Legend Errors 80 to 87 z Error Persists gt Error Clears gt See additional text Ensure connectors are dry Check connections After drying if error clears moisture on the connector caused the error Not necessary for E80 Reposition Independently One of the probe ensure swap probe and devices is probe is fully cable Swap damaged inserted into cable only for Introducer E87 Swap probe Both of the and cable at the devices are
18. Management Tube Kit Connect the probe to the Cooled RF Connecting Cable PM1058 Rev 06 09 Page 12 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries Or S el a a Detailed Equipment Set Up 1 Connect the Generator to the Pain Management Pump Unit e Connect the male connector of the Pain Management Pump Connector Cable to the generator e Connect the female connector of the Pain Management Pump Connector Cable to the Pump Unit e Push the connectors as far in as possible and then tighten by turning the collar clockwise 2 Plug in the Generator e Plug the power cord into the Pain Management Generator and connect the generator directly to a grounded receptacle e Turn the generator on PM1058 Rev 06 09 Page 13 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries 3 Insert Tube Kit into the Pain Management Pump Unit e Remove the Pain Management Tube Kit from the sterile package e Put the burette into the Pump Unit s burette holder e Open the pump head lid and thread the thicker tubing from the bottom of the burette into the pump head tube holder e Ensure that the tubing is properly placed between the notches and along the center channel beneath the pump
19. a very good conductor when using direct current Resistive heat can be generated but the flow of current cannot be controlled easily and it can damage the cells Using direct current to heat tissue may produce unpredictable tissue temperatures and irregular shaped lesions Excessive temperatures would lead to burning of tissue gas formation and uncontrolled destruction of tissue lonic Heating with AC Another way electrical energy is converted to heat in tissue is by ionic heating To overcome the drawback of direct current use of alternating current for medical applications was pioneered by Cushing and Bovie in the 1920s originally for hemostasis Later in the 1950s Aranow and Cosman deployed alternating current for creating neural lesions Alternating current conducts through tissue with less resistance and more control than direct current The greater the alternating current frequency the greater the conductance Alternating current causes the charged molecules or ions in the tissue to follow the directional variation of the alternating current resulting in molecular vibration The molecular vibration produces heat due to frictional forces This effect is called ionic heating The body is a complex system that uses electric current for a wide range of functions from regulating a heart beat to sending the sense of touch from a finger to the brain If alternating current is applied to the body using frequencies similar to those
20. al Company Inc in the United States of America and or other countries 4 Obtain a lateral fluoroscopic image Ensure the introducer tip is contacting bone on the posterosuperior border of the transverse process 5 Rotate the C arm back to an A P view Remove the stylet from the introducer A small volume less than or equal to 1cc of local anesthetic is optionally administered to the target site through the introducer Place the ThoraCool Probe into the introducer ensuring that it is seated snuggly in the hub Note that the ThoraCool Probe is 2 mm shorter that the stylet The probe is designed to sit 2 mm off of the dorsal surface of the transverse process to ensure that the thermocouple is not forced into bone PM1058 Rev 06 09 Page 24 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries Introducer without stylet Introducer with stylet Introducer with probe Introducer with probe Note that there will be up to 6mm of distal lesion projection from the tip of the electrode Ensure there is adequate distance between the tip of the electrode and the foramen of the segmental nerve root to minimize the risk of inadvertent heating to this structure 6 The probe should be advanced into the intertransverse space until the radiopaque band Is level with the superior margin of the transvers
21. al branches of the dorsal rami are responsible for relaying nociceptive signals from the z joint and the surrounding structures to the CNS Anatomical studies suggest that the course of the medial branches is variable This is demonstrated not only between specimens but also from side to side and from level to level Between levels the variability of the nerve path decreases at the superolateral aspect of the transverse process This is a bony landmark identifiable under fluoroscopy that can be used to locate the medial branch This variability presents a challenge for clinicians seeking to treat thoracic z joint pain Descending articular A T6 7 branch from T5 MB Z Joint Dorsal ramus Medial branch Transverse process Ascending articular branch from T6 MB Figure 5 Thoracic z joint innervation i UPPER Figure 6 Medial branch path variation adapted from Chua 1994 figures 3 3 and 3 4 PM1058 Rev 06 09 Page 20 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries Procedure Preparation e The patient should be N P O nothing by mouth prior to the procedure Prophylactic antibiotics can be administered prior to the procedure based on physician preference Place the patient in the prone position on the table e The patient must be monitored properly throughout the procedure
22. aligning the vertebral end plates at the level to be treated The transverse process should be identifiable If not the image can be rotated in the contralateral oblique direction until the transverse process becomes more visible as it separates from the rib Pinocchio View PM1058 Rev 06 09 Page 22 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries 2 The c arm is rotated ipsilateral oblique until the costotransverse joint lucency comes into view The rotation of the c arm from A P will likely range from 10 15 depending on the anatomy 3 The introducer follows this ipsilateral oblique path to the superolateral aspect of the transverse process Insert the introducer at the inferolateral aspect of the costotransverse joint lucency Advance the introducer up to the superomedial aspect of the costotransverse joint along the beam This trajectory is important to ensure that the electrode is placed at the superolateral aspect of the transverse process in the intertransverse space It is important to confirm that the introducer needle is at the Superior margin of the transverse process The tip of the introducer should be contacting bone Skin Insertion PM1058 Rev 06 09 Page 23 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medic
23. ates of America and or other countries ThoraCool RF System Component Troubleshooting Troubleshooting during equipment set up Damage to the ThoraCool Introducer Visually inspect the packaging before use The sterile pouch should not have any packaging of a sterile ThoraCool Probe and Pain holes device Management Tube Kit Discard the device if packaging has been compromised Obvious visual damage Cooled RF Connector Cable Visually inspect the products for any damage Look for damage such as cuts to any product Pain Management Pump Unit cracks breaks and bends ThoraCool Probes ThoraCool Introducers Pain Management Do not use damaged equipment Tube Kits Electrical connectors do ThoraCool Probe and Cooled not connect BE Connecior Cable Check that the connector s keys are lined up in the proper orientation Turn the connector until it slides in the mating connector Ensure that the connectors are clean and unobstructed Check that the connectors being connected have the same number of pins and that the pins are not damaged connect Management Tube Kit Remove the white luer lock caps The Pump will not Pump Unit and Pain Fully open the cover for the pump and place the tubing coming from the bottom of accept the Tube Kit Management Tube Kit the burette of the Tube Kit into i e above the L shaped tube Guides see step 3 in tubing the Equipment Set Up section can not be removed leaking or is occluded PM1058 Rev
24. e lid Upper 80 mL and Lower 70 mL Fill Lines PM1058 Rev 06 09 Page 15 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries 5 Place the introducer and probe in the patient e Prepare the patient and place the ThoraCool Introducer and Probe See Section 8 for Placement Guidelines 6 Place the Dispersive Electrode on the patient e Place the Dispersive Electrode on the patient according to the Instructions for Use provided with the kit 7 Connect probes to Pain Management Tube Kits e Pass the tubing and electrical connections on the probe out of the sterile field e Remove the caps from the two luer locks on the ThoraCool Probe and the Tube Kit Connect the luer locks snugly Maintain sterility of the tubing s inner pathway so in case water is accidentally spilled in the sterile field sterility will not be compromised Luer Lock Cap 4 I Ww P Q PM1058 Rev 06 09 Page 16 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries 8 Connect the probe to the Cooled RF Connecting Cable e Connect the male connector on the ThoraCool Probe to the female connector on the Cooled RF Connecting Cable e Connect the Cooled RF Connecting Cable to the generato
25. e process PM1058 Rev 06 09 Page 25 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries 7 A Pinocchio View contralateral oblique can be used to visualize the probe on the transverse process The impedance displayed on the screen of the Pain Management Generator should not exceed 500 ohms Impedance values exceeding 500 ohms may indicate that the probe is positioned in tissue not suitable for lesioning or that the probe is not fully seated in the hub of the introducer The position of the probe is secured by Sliding the green depth stopper down to the surface of the skin PM1058 Rev 06 09 Page 26 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries 8 Create the first lesion according to the parameters outlined in Lesion Parameters Section 9 of this document Suggested parameters include Set Temperature 60 C Time 2 30 Monitor the patient s response during lesioning for non concordant pain in the side chest or shoulder The lesion can be stopped at any time by depressing the ON OFF button on the lower right corner of the pain generator Isotherm Celcius Diameter 12 mm posed probe length 5 5 mm _ Probe PM1058 Rev 06 09 Page
26. erator to power outlet Check for an error message on the generator Possible error codes include E108 and E123 Follow flow chart for trouble shooting actions Visually inspect the probe or cable for damage Ensure that devices are dry and at room temperature If problem persists discontinue use Small oscillations or spikes might be seen in temperature during treatment mode This may be due to the probe or patient moving Check the fluoroscopy image to confirm the probes have not moved to an unsafe location If they have moved stop the procedure press the Output On Off Button and reposition the probe Very large oscillations or spikes gt 15 C may be seen during RF delivery if the probe is positioned within dense connective tissue or bone This will likely be accompanied by a higher that normal impedance reading gt 500 Q Stop the procedure press the Output On Off Button and reposition the probe Very large oscillations or spikes gt 15 C may also indicate that the probe is damaged Visually inspect the probe and discard if damaged Check the power output If it power is consistently equal to the Power Limit typically 25 W as modyfied in Advanced Settings Screen then the site of the attempted lesion may be unusually thermally conductive Try repositioning the electrode slightly Confirm the electrode position with fluoroscopy and repeat the lesion If the power is below the Power Limit and repositioning and lesi
27. f America and or other countries The graph on this page is also similar to the ideal graph except that the POWER has reached the power limit of 25 W for a short period of time during the beginning of the procedure As a result it has taken about 15 seconds longer than usual for the COOLED RF TEMP to reach SET TEMPERATURE This is periodically seen when the probe has been placed in particularly dense connective tissue The power limit has ensured that the lesion formed is formed in a safe and uniform manner If the SET TEMPERATURE is unable to reach SET TEMPERATURE because of this feature stop the procedure and reposition the electrode Generator graph showing that reaching the power limit is okay PM1058 Rev 06 09 Page 35 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries An example of a graph that indicates a poor procedure is shown below The COOLED RF TEMP and POWER lines have become erratic indicating that the electrode is not able to deliver RF energy in a consistent manner for this tissue location This will likely be accompanied by a higher than normal impedance reading gt 500 Q9 This may be the result of non homogenous tissue around the active tip of the electrode or by placing the active tip in dense connective tissue or b
28. in magenta An ideal procedure graph as shown below has fairly smooth lines with the COOLED RF TEMP rising steadily until the SET TEMPERATURE dashed yellow line is reached The POWER will increase until the COOLED RF TEMP reaches SET TEMPERATURE Following this the POWER may plateau or decrease slightly over the remainder of the procedure Typical POWER values range from 5 to 25 Watts Generator graph of an ideal procedure PM1058 Rev 06 09 Page 33 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries The graph on this page is similar to the ideal graph except there is a small blip in both lines at about 1 minute This is commonly seen if the patient moves to get more comfortable or coughs It may also be seen if the probe is bumped or moved This is likely not a problem but it is a good idea to check the lateral and AP fluoroscopy views to make sure the probe is still in a desirable position STIMULATION MCHE weTane TEC AUTO OLTADE CURRENT TEMP Generator graph showing a small blip is okay PM1058 Rev 06 09 Page 34 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States o
29. issue contact A Excessive RF Power Measured Possible intermittent tissue contact Possible defective probe s or cable s A High Impedance Detected Check probe cable and dispersive return electrode connections Possible poor tissue contact Probe or cable may be defective A Unrecognized Probe Type See User Manual for a list of valid probes Please note error code and contact technical support if problem persists PM1058 Rev 06 09 A Pump Malfunction Ensure pump lids are fully closed and cable is securely connected Pump unit may be defective A Dynamic Probe Pump Mapping Failure Check probe and cable connections ensure fluid circuitry is connected correctly and free from obstruction Repeat priming while squeezing the upper and lower jaw of the pump head Probe s or cable s may be defective Contact technical support if problem persists A Pump Current Limit Check pump unit and ensure cable is securely connected Contact technical support if problem persists A Cooled Temperature Out Of Range Outside 18 34 C expected range Probe s cable s or pump unit may be defective A Probe A Not Connected Check probe and cable connections Probe or cable s may be defective A Invalid Probe A Temperature Reading Check probe and cable connections Probe or cable s may be defective Try new probe and cable s if problem persists Page 43 of 48 Baylis Medical Company Inc 2009 Thora
30. ity lifting or other forms of increased physical activity for 1 3 days following the procedure PM1058 Rev 06 09 Page 29 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries 9 Lesion Parameters Overview This section describes the parameters used to control the heating profile during the procedure In this section you will learn e What the modifiable parameters are e How the parameters affect the heating e Suggested parameters to use Parameters used to create heating profile The parameters available to control the heating profile are Ramp Rate Set Temperature Time Set Temperature Lai ie ERES 9 sunyesoduia L Ramp Rate C minute Duration a P A N minutes Time min There is a temperature sensor at the tip of the ThoraCool Probe The generator will monitor this temperature sensor and automatically deliver the required power to raise the temperature of the target tissue The shape of the heating profile is determined by the parameters Ramp Rate Set Temperature and Time At the beginning of the procedure the temperature is lower than body temperature because the pump is running and cooling has begun The probe temperature will increase at the Ramp Rate until it PM1058 Rev 06 09 Page 30 of 48 Baylis Medical Company Inc 2009 ThoraCool i
31. ity and increases the risk of inadvertent heating of this structure e For all targets the introducer should be directed towards the target site until the tip is in contact with bone When the stylet is removed and the electrode is inserted It may be necessary to advance the active tip of the probe so that the radiopaque band reaches the superior border of the transverse process e Ensure that the probe is seated firmly in the introducer before proceeding This will achieve the appropriate electrode length for treatment e The stylet should always be replaced in the introducer prior to repositioning The electrode is not designed to create new pathways through tissue PM1058 Rev 06 09 Page 18 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries Thoracic Anatomy 7 g r Fluoroscopic Image p This is an A P view of a thoracic spine showing the transverse process lamina and rib Transverse Process E Lamina Illustration of the thoracic spine Compare the above image with this illustration of the posterior thoracic surface PM1058 Rev 06 09 Page 19 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries Thoracic Z joint Innervation Medi
32. l barriers to recovery Active radicular pain radiculopathy Immunosuppression PM1058 Rev 06 09 Page 11 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries 7 Setup Instructions Overview The following section outlines the procedure for setting up the ThoraCool Pain Management System We have provided two set up guides e Quick Start Equipment Set Up designed for users who have previously handled the equipment Detailed Equipment Set Up designed for users who are using the system for the first time Equipment Set Up Diagram The Pain Management ThoraCool System consists of Reusable Equipment 1 Pain Management Generator V2 2A or higher 2 Pain Management Pump Unit 3 Pump Connecting Cable not shown 4 Pain Management Cooled RF Connector Cable Disposable Kit 5 One Pain Management Tube Kit 6 One ThoraCool Pain Management Probe 7 Two ThoraCool Pain Management Introducers 8 One Dispersive Grounding Pad not included in kit Quick Start Equipment Set Up Connect the Generator to the Pump Unit Plug in the Generator and turn it on Insert one Pain Management Tube Kit into the Pain Management Pump Unit Fill the burette with sterile water Connect the Cooled RF Connecting Cable to the Generator Place the introducer and probe in the patient Connect probes to Pain
33. ntrol of RF energy delivery throughout the procedure e Each probe includes a 4 cable and tubing extension to reach out of the sterile field 2xThoraCool Pain Management Introducer Model THI 17 75 5 5 Important features e An introducer is comprised of a fully insulated cannula and a sharp trocar tipped stylet e The 17 gauge introducer allows for accurate placement of the probe PM1058 Rev 06 09 Page 9 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries 1xPain Management Tube Kit Model TDA TBK 1 Important features e One tube kit is required for a procedure e tis used for circulation of sterile l He water through the ThoraCool Probe aE for the purpose of cooling the electrode e The Pain Management Pump Unit pumps water through the tube kit j The Tube Kit comprises medical 1 grade tubing and a burette that SY holds sterile water PM1058 Rev 06 09 Page 10 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries 6 Patient Selection Candidates for thoracic z joint neurotomy must have a history of chronic thoracic z joint pain for at least six months and meet the selection criteria It is important to adhere to these criteria for
34. one Immediately stop the procedure and reposition the electrode z ay BAYLIS MEDICAL COMPANY INC TIME min Eala 5 so iF r SET TEMP C 0 38 60 av COOLED RF DATA PUMP ON TIME min 100 A c Y 80 40 VW 60 30 0 20 Wy 20 10 0 p 0 N STIMULATION MODE j VOLTAGE CURRENT tees _ Sn a3 a Q on C J PAIN MANAGEMENT GENERATOR h ni UN 2 J OFF J F E T E Generator graph of a poor procedure PM1058 Rev 06 09 Page 36 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries 11 Troubleshooting Overview In this section you will e Learn how to identify potential problems with system components e Become familiar with the Generator Error and Fault Codes that may appear during a ThoraCool procedure Trouble Shooting Pain Management ThoraCool System Components In addition to the information contained within this document each ThoraCool Kit has a troubleshooting table in its Instructions for Use to assist the user in diagnosing potential problems PM1058 Rev 06 09 Page 37 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United St
35. oning does not resolve the issue discontinue use of the probe Page 41 of 48 Pain Management Generator Error Fault Codes for Cooled RF Mode e fan error fault condition should occur a pop up message will display an error fault code in the center of the screen e The error fault event text message displayed including possible cause error fault code and recoverable non recoverable indications regarding Cooled RF Mode are listed in Table 1 NOTE For recoverable faults the error code is displayed for approximately 10 seconds the Generator will automatically transition back to the previous READY state For technical assistance it is important to note the error fault code displayed by the Generator PM1058 Rev 06 09 Page 42 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries Table 1 Cooled Error Fault code interpretation LCD Text Message LCD Text Message A Measured Temperature Exceeds Setpoint Possible high impedance or desiccated tissue at probe tip A Measured Power Exceeds Setpoint Please check all probe and cable connections Possible intermittent cable or poor tissue contact A Excessive RF Current Measured Possible short between electrodes or defective probe or cable A Excessive RF Voltage Measured Possible intermittent cable connection or loss of t
36. pany Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries Trouble Shooting Flow Chart Legend Error Persists Errors 106 108 123 125 Error Clears See additional text Errors 108 123 125 Invalid water temperature Ensure sterile water is gt 17 C and lt 34 C Improper 7 connections Check all connections Damaged Cable Swap Cooled RF Connector Cable Swap ThoraCool Probe Damaged Probe Internal error requires repair Call Clinical Support PM1058 Rev 06 09 Page 47 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries References 1 Aranow S The use of radiofrequency power in making lesions in the brain J Neurosurg 1960 17 431 8 2 Borggrefe M Hindricks G Haverkamp W et al Catheter ablation using radiofrequency energy Clin Cardiol 1990 13 127 31 3 Chua WH Clinical Anatomy of the Thoracic Dorsal Rami Medical Sciences New South Wales University of Newcastle 1994 220 4 Dadd JS Ryan TP Platt R Tissue impedance as a function of temperature and time Biomed Sci Instrum 1996 32 205 14 5 Gabriel C Gabriel S Corthout E The dielectric properties of biological tissues 1 Literature surveys Phys Med Biol 1996 41
37. r 9 Connect the Dispersive Electrode to the Generator Now the equipment set up is complete PM1058 Rev 06 09 Page 17 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries 8 Procedure Guidelines Overview This section describes the positioning of the introducers and probe within the patient In this section you will learn e The general safety guidelines for placement e Brief thoracic anatomy with fluoroscopic and photographic images e Step by step placement technique General Safety Guidelines For safe and effective tissue heating and safe anatomical access abide by the following guidelines e For desired tissue heating and anatomical access abide by the following guidelines e For thoracic z joint neurotomy the electrode should be directed at the superolateral aspect of the transverse process Placement of the electrode more medial on the transverse process brings the electrode closer to the segmental nerve root and farther from the medial branch this can increase the risk of both inadvertent heating of the segmental nerve root and inadequate heating of the medial branch e In a lateral fluoroscopic view the electrode should not be more ventral than the anterior margin of the transverse process Placement more ventral to the target point brings the electrode closer to the pleural cav
38. roducers and electrodes are directed at the target using a down the beam 10 15 ipsilateral oblique approach Summary of System Benefits The ThoraCool System creates reproducible large volume lesions by utilizing e Temperature controlled radiofrequency energy application Internally cooled electrodes Application specific electrode design Impedance monitoring User friendly design and interface PM1058 Rev 06 09 Page 7 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries 5 Technical Description of the Equipment Overview In this section you are going to learn about all of the components of the ThoraCool System You will learn the function of each device and the relationship of the device within the system Baylis Pain Management Generator Model PMG TD V2 2 or higher Important features e A software based computerized radiofrequency generator e Several safety features are incorporated into the control algorithm For example the generator can detect broken or improperly set up equipment and give appropriate error messages e tis designed to power and control the pump unit and provide eta automatically controlled parameters designed for the procedure Pain Management Pump Unit Model TDA PPU 1 Important features e The pump unit circulates sterile water f
39. ry Time is the duration of radiofrequency energy delivery including the temperature ramp up and plateau A longer Time will allow a greater volume of tissue to be heated until thermal equilibrium is reached The optimum Time is long enough for adequate volume heating without excessive procedure time Time can be changed at any point before or during the RF delivery Power Limit is the maximum power in Watts that the generator will output at any time during the procedure Power output will vary throughout the procedure as required to achieve the desired Ramp Rate and Set Temperature Typically power values are higher during the temperature ramp and lower once the probe has reached Set Temperature If the Power Limit is reached during temperature ramp the generator will continue to deliver RF at this maximum value This may increase the Ramp Rate by several seconds but will ensure that the lesion forms in a safe and consistent manner If the Power Limit is set too high it is possible to have irregular lesion shapes or excessive heating Refer to the following page for the suggested lesion parameters PM1058 Rev 06 09 Page 31 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries Suggested Parameters The suggested parameters used for treating a patient with the ThoraCool System are Set Temperature 60
40. s a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries reaches the Set Temperature The temperature will remain at the Set Temperature until the Time is complete Effect of Parameters Ramp Rate is the rate of increase in temperature per minute as measured by the probe s temperature sensor A slower Ramp Rate results in better control of heating larger volumes of heated tissue and more consistent temperature profile A faster Ramp Rate results in shorter procedure time In conventional non cooled RF procedures such as a z joint rhizotomy the ramp rate is usually about 15 seconds The optimum ramp rate for the ThoraCool System is only slight longer lasting 25 seconds It must be understood that this time has been optimized to balance procedural speed and lesion consistency Ramp Rate can only be changed in the Advanced Settings of the generator Set Temperature is the desired temperature of the probe s electrode surface The temperature will increase at the Ramp Rate until it reaches the Set Temperature which is then maintained Due to the cooling of the electrodes the Set Temperature will be 10 15 Celsius lower than the tissue a few millimeters from the electrode The level of the Set Temperature in combination with the Ramp Rate and Time will affect the temperature throughout the tissue Set Temperature can be changed at any time before or during the RF delive
41. s been demonstrated to significantly affect lesion size PM1058 Rev 06 09 Page 5 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries In summary by cooling the tissue adjacent to the electrode with cool water a larger volume lesion can be created This is accomplished by increasing the time of the procedure or the energy output of the RF generator Temperature 80 C Non cooled Cooled Distance Probe Figure 3 Temperature distribution of non cooled and cooled RF electrodes The circulation of coolant through an electrode also affects the shape of the lesion A monopolar cooled RF electrode for example can be designed to create a lesion that is either spherical or elliptical in shape A portion of this lesion can project distally from the probe heating tissue that might otherwise be difficult to access These distinct lesion characteristics allow electrode placement in any angle towards the target In addition the spherical shape accounts for any angle of nerve entry or exit to maximize the length of ablation In the case of the spherical lesion created by the ThoraCool System the lesion shape accommodates the variable nerve path of the medial branch Figure 4 G rs Figure 4 Spherical lesions accounts for any angle of nerve entry or exit PM1058 Rev 06 09 Page 6 of
42. st at the proximity of the electrode and decreases with increasing distance RF devices often contain temperature sensors Note that the electrode itself does not heat up Instead the tissue heats from ionic heating and the heat conducts back to the electrode where the sensor indicates the tissue temperature local to the electrode This decreasing gradient of PM1058 Rev 06 09 Page 4 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries current density limits the size of the heat lesion that can be produced With a constant power a heat lesion will only grow to a limited size because the amount of heat created will come to equilibrium with the heat removed by the surrounding tissue and blood flow Figure 2 Current density represented by arrows around an electrode represented by the circle Note how the tail ends of the arrows are more concentrated at the electrode and less dense as the arrows radiate away from the electrode A way to increase the volume of tissue heated using RF is to increase the power However increasing power also has its limitations AS power increases so does the temperature of the tissue in close proximity to the electrode Exceeding 95 C may cause cavitations tissue charring and uncontrolled lesion formation It has been demonstrated that tissue impedance the measurement of tiss
43. the safety of the patient and success of the treatment The physician must be trained to diagnose thoracic z joint mediated pain Selection Criteria Candidates for the Thoracic Z joint Neurotomy procedure must meet the following inclusion criteria e Predominantly axial pain below the T1 and above L1 vertebrae e Greater than 80 pain relief from two separate medial branch blocks with no more than 0 3 ml of injectate per block It is recommended to use higher concentration anesthetic such as 0 75 bupivacaine or 4 lidocaine for a more effective block e Chronic axial pain lasting for longer than six months e Age greater than 18 years e Failed to achieve adequate improvement with comprehensive non operative treatments including but not limited to activity alteration non steroidal anti inflammatory physical and or manual therapy and fluoroscopically guided steroid injections in and around the area of pathology e All other possible sources of back pain have been ruled out including but not limited to the intervertebral discs the costovertebral joint the costotransverse joint symptomatic spondylolisthesis and other regional soft tissue structures Candidates for the Thoracic Z joint Neurotomy procedure will be excluded if they meet any of the following criteria Pregnancy Systemic infection or localized infection at the anticipated introducer entry site History of coagulopathy or unexplained bleeding Irreversible psychologica
44. tion in the Instructions for Use provided with the components of the ThoraCool Pain Management System The Instructions for Use includes important information such as warnings precautions contraindications and trouble shooting The Instructions for Use for each component must be read prior to use PM1058 Rev 06 09 Page 2 of 48 Baylis Medical Company Inc 2009 ThoraCool is a trademark and or a registered trademark of Baylis Medical Company Inc in the United States of America and or other countries 3 Physics of the ThoraCool Pain Management System Overview This section briefly explains how the ThoraCool System heats nervous tissue In this section you will learn e The reason why high frequency alternating current is used to heat tissue e The reason why the ThoraCool Probes are internally cooled Direct Current amp Alternate Current Electric current refers to the amount of charge that passes through a surface per measure of time At an atomic level current is the flow of electrons A current that moves in the same direction around a circuit is referred to as Direct Current DC A current whose direction alternates continuously back and forth is referred to as Alternating Current AC see Figure 1 The number of times that the current alternates back and forth in a second is known as frequency Frequency is measured in Hertz For example 60 Hertz means that the current alternates back and forth 60 times per second
45. ue resistance to alternating current decreases as the temperature increases up to 60 to 70 C further increase in temperature however leads to a rapid increase in tissue impedance As tissue impedance increases at high temperatures the further flow of current becomes more difficult and harder to control Internally Cooled RF Systems Another means of increasing the volume of the lesion is by using internally cooled RF electrodes This technique was first proposed by Wittkampf in 1988 The hollow lumens of internally water cooled probes permit continuous cooling of the electrode with a fluid Internally cooled RF electrodes act as heat sinks that remove heat from tissue adjacent to the electrode Consequently time duration or power deposition can be increased during the procedure without causing high impedance and tissue charring around the electrodes As a result internally cooled electrodes can produce much larger lesions compared to non cooled electrodes Furthermore the tissue in proximity to the electrode does not need to be as hot in order to reach target temperatures at greater distances away from the electrode Figure 3 The water used for circulation in cooled RF lesions need only be room temperature When used for cooled RF water temperatures of 5 C have been shown to not significantly affect lesion size in ex vivo hepatic ablations compared to water temperatures of 25 C However increasing flow rate of the coolant ha
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