Surgical devices and methods of use thereof
Contents
1. and refer to the interfacial energies of the liquid vapor solid vapor and solid liquid interfaces respec tively If the contact angle 0 is less than 90 degrees the liquid is said to wet the solid If the contact angle is greater than 90 degrees the liquid is non wetting zero contact angle 0 represents complete wetting Thus preferably the contact angle is less than 90 degrees The bipolar devices disclosed herein are particularly useful as non coaptive tissue sealers in providing hemostasis during surgery In other words grasping ofthe tissue is not necessary to shrink coagulate and seal tissue against blood loss for example by shrinking collagen and associated lumens of blood vessels e g arteries veins thereby inhibiting blood flow therethrough and therefrom to provided the desired hemostasis of the tissue More particularly the devices may be useful to shrink blood vessels either severed or unsevered during spine surgery such as blood vessels of the vertebral venous and or arterial systems during for example a discec tomy Intervertebral discs are flexible pads of fibrocartilaginous tissue tightly fixed between the vertebrae of the spine The discs comprise a flat circular capsule roughly an inch in diameter and about 0 25 inch thick made of a tough fibrous outer membrane called the annulus fibrosus surrounding an elastic core called the nucleus pulposus Under stress it is possible forthe nucleus pulp2. 65 8 trosurgical unit 14 it may be plausible to use other electro surgical devices with electrosurgical unit 14 such as monopo lar devices or it may be plausible to use the electrosurgical devices disclosed herein with another electrosurgical unit other than electrosurgical unit 14 As shown in FIG 7 exemplary bipolar electrosurgical device 30a comprises a single stationary arm 100 which comprises a rigid self supporting hollow shaft 102 As shown shaft 102 is preferably angled to provide better view ing of the distal tip portion 106 of device 30a during use thereof Shaft 102 preferably comprises metal tubing and more preferably thick walled hypodermic stainless steel tub ing In this manner shaft 102 has sufficient rigidity to main tain its form during use of device 30a without kinking or significant bending and support the distal portion 106 in rigid relation to a proximal handle 104 In other embodiments shaft 102 may be made of an electrical non conducting mate rial such as a polymer or composite material Proximal handle 104 comprises mating handle portions 104a 1045 Handle 104 is preferably made of a sterilizable rigid non conductive material such as a polymer Also handle 104 is preferably configured slender along with the rest of the device 30a to facilitate a user of device 30a to hold and manipulate device 30a like a pen type device Device 30a also comprises a flexible fluid delivery tubing 28 which i
3. p 7 A 1 Y Br MM H cate ty Ma rin tan dale merci tin 7 3 U S Patent Jan 8 2013 Sheet 11 of 15 US 8 348 946 B2 4 co 326 U S Patent Jan 8 2013 Sheet 12 of 15 US 8 348 946 B2 US 8 348 946 B2 Sheet 13 of 15 Jan 8 2013 U S Patent ml m P ee pci P E 2 y d d ot 1 Mu T 2UU 1 CN XM d 4 Ame i DRM 4 MS d i SS FH lt V N Y Me ett i f Pad 5 b x 3 E H qe Vt s s E Q iai iic D 5 U S Patent Jan 8 2013 Sheet 14 of 15 US 8 348 946 B2 U S Patent Jan 8 2013 Sheet 15 of 15 US 8 348 946 B2 Eum 229 US 8 348 946 B2 1 SURGICAL DEVICES AND METHODS OF USE THEREOF CROSS REFERENCE TO RELATED APPLICATIONS The present application is a divisional of U S application Ser No 12 053 030 filed Mar 21 2008 now U S Pat No 8 216 233 issued Jul 10 2012 which claims the benefit ofthe filing date of U S Provisional Application Ser No 60 896 768 filed Mar 23 2007 The teachings of each of these applications are incorporated herein by reference FIELD This invention relates to surgical devices systems and methods for use upon tissues of a human
4. 864 2001 0001314 2001 0014806 2002 0049438 2002 0077626 2002 0198520 2003 0233023 2004 0243121 2005 0059966 2005 0070894 2005 0090816 2005 0154386 2005 0288665 2006 0052776 2006 0106375 2006 0149225 2007 0027449 2007 0270791 U S PATENT DOCUMENTS Bl Bl Bl B2 B2 B2 B2 B2 B2 B2 B2 B2 B2 B2 B2 B2 Al Al Al Al Al Al 6 2003 8 2003 12 2003 3 2004 11 2005 12 2005 9 2006 9 2006 12 2006 2 2007 11 2008 8 2009 11 2009 10 2010 10 2010 10 2010 5 2001 8 2001 4 2002 6 2002 12 2002 12 2003 12 2004 3 2005 3 2005 4 2005 7 2005 12 2005 3 2006 5 2006 7 2006 2 2007 11 2007 Eggers et al Fung et al Hedge et al McClurken et al Shapeton et al Baerveldt et al Jenkins et al Cosmescu Goble Cooper et al Swanson Saadat et al Sugi McClurken Auge II et al Morgan et al Davison et al Ellman et al Sharkey et al Ellman et al Coen et al Khaghani et al 600 18 Lee et al McClurken et al McClurken McClurken et al West et al Woloszko Desinger et al Werneth et al McClurken Godara et al Wang et al 2008 0033421 Al 2 2008 Davis et al 2008 0221567 Al 9 2008 Sixto et al 2009 0118732 Al 5 2009 Desinger 20090156981 Al 6 2009 Fay et al 2009 0177192 Al 7 2009 Rioux etal 2009 0270856 Al 10 2009 Saadat et al 2010 0036371 Al 2 2010 Park et al 2010 0100095 Al 4 2010 McClurken et al 2010 0114095 Al 5 2010 Janssen etal 2010 0160906 Al 6 2010 Jarrard 2010 0
5. FIG 1 the fluid delivery tubing 28 passes through pump 32 As shown pump 32 comprises a peristaltic pump and more specifically a rotary peristaltic pump With a rotary peristaltic pump a portion of the delivery tubing 28 is loaded into the pump head by raising and lowering the pump head in a known manner As best shown in FIG 6 fluid 24 is conveyed within the delivery tubing 28 by waves of contrac tion placed externally on the tubing 28 which are produced mechanically typically by rotating pinch rollers 57 which rotate on a drive shaft 55 and intermittently compress the tubing 28 against an anvil support 58 Alternatively pump 32 may comprise a linear peristaltic pump With a linear peri staltic pump fluid 24 is conveyed within the delivery tubing 28 by waves of contraction placed externally on the tubing 28 which are produced mechanically typically by a series of compression fingers or pads which sequentially squeeze the tubing 28 against a support Peristaltic pumps are generally preferred as the electro mechanical force mechanism here rollers driven by electric motor does not make contact the fluid 24 thus reducing the likelihood of inadvertent contami nation In a preferred embodiment the fluid 24 comprises saline and even more preferably normal physiologic saline Although the description herein may make reference to saline asthe fluid 24 other electrically conductive fluids can be used in accordance with the invention
6. FIG 6 shows exemplary block diagram of how electro surgical unit 14 processes the inputs of RF power setting and the fluid flow rate setting either Q4 or Qy to control the pump speed and therefore the throughput of fluid expelled by the pump 32 As shown user selected input values for the RF power setting and the fluid flow rate setting of either low medium and high corresponding to Q Q and as well as activating the priming function are entered US 8 348 946 B2 7 into electrosurgical unit 14 by pushing corresponding switches for these parameters positioned on the front panel of the electrosurgical unit 14 As shown in FIG 6 the RF power setting switches 46a 46b the flow rate setting switches 52a 525 52c and the priming switch 54 are a display panel module 40 preferably comprising a printed circuit board which receives the inputs into electrosurgical unit 14 The user selected input values for RF power fluid flow rate and priming are then conveyed via corresponding input sig nals 41 to a main module 43 which preferably comprises a printed circuit board including a computer chip 45 a radio frequency generator 47 and a pump controller 48 As shown display panel module 40 and main module 43 as well as other components receive power from a power supply module 49 which also comprises a printed circuit board Computer chip 45 preferably comprises a micro processor unit a memory and an input o
7. No 60 896 768 filed on Mar 23 2007 The invention provides surgical devices and methods to treat tissue In one device embodiment the invention comprises 51 Int Cl bipolar electrosurgical device to treat tissue in a presence of 18 14 2006 01 radio frequency power and a fluid provided simultaneously 606 50 606 40 froma distal portion of the device with the device comprising 58 Field of Classification Search 606 21 31 a disc shaped distal end In one method embodiment the MU 606 41 48 50 invention comprises a method of treating tissue having a See application file for complete search history blood vessel during spine surgery with the method compris ing pressing a portion ofthe blood vessel against a supporting 56 References Cited spine structure with a surgical device to provide a compressed U S PATENT DOCUMENTS 4 936281 A 6 1990 Stasz 5 098 431 A 3 1992 Rydell 5 383 876 A 1 1995 Nardella 5 395 363 A 3 1995 Billings et al portion ofthe blood vessel and heating the compressed por tion ofthe blood vessel with the surgical device sufficiently to inhibit a blood flow through the vessel after the surgical device is removed from the blood vessel 16 Claims 15 Drawing Sheets US 8 348 946 B2 Page2 6 575 968 6 602 242 6 656 174 6 702 810 6 960 200 6 979 328 7 104 990 7 112 199 7 147 637 7 175 644 7 455 669 7 571 729 7 621 910 7 811 282 7 819 861 7 819
8. While a conductive fluid is preferred as will become more apparent with further reading of this specification fluid 24 may also comprise an electrically non conductive fluid The use of a non conductive fluid is less preferred than conduc tive fluid however the use of a non conductive fluid still provides certain advantages over complete elimination of the fluid and the use of a dry electrode including for example reduced occurrence of tissue sticking to the electrode of device 30 and cooling of the electrode and or tissue There fore it is also within the scope of the invention to include the use ofa non conducting fluid such as for example deionized water As shown in FIG 1 electrosurgical device 30 is connected to electrosurgical unit 14 via a cable 34 which comprises a plurality of electrically insulated wire conductors and at least one plug 36 at the end thereof The electrosurgical unit 14 provides radio frequency RF energy power via cable 34 to electrosurgical device 30 As shownin FIG 2 plug receptacle 38 of electrosurgical unit 14 receives the plug 36 of device 30 therein to electrically connect device 30 to the electrosurgical unit 14 Preferably the fluid delivery tubing 28 is provided as part of cable 34 and produced with the electrically insulated wires via plastic co extrusion FIG 2 shows the front panel ofthe electrosurgical unit 14 power switch 42 is used to turn the electrosurgical unit 14 on and off Aft
9. an electrosur gical apparatus to provide controlled delivery of radio fre quency power and a fluid to an electrosurgical hand held device to treat tissue The apparatus comprises a radio fre quency generator to deliver the radio frequency power with the radio frequency power from the radio frequency genera tor selectable at a radio frequency power level a pump to deliver the fluid a primer to prime the hand device with the fluid a control system to control a flow ofthe fluid delivered by the pump with a functional relationship between the radio frequency power level and the flow ofthe fluid the functional relationship to increase the flow ofthe fluid in response to an increase in the radio frequency power level and to decrease the flow of the fluid in response to a decrease in the radio frequency power level and a fluid flow selector which changes the functional relationship between the radio fre quency power level and the flow of the fluid In another embodiment the invention provides a bipolar electrosurgical device to treat tissue The device comprises a handle anda shaft extending distally from the handle with the 20 25 30 35 40 45 50 55 60 65 2 shaft supporting the distal portion of the device in rigid rela tion to the handle The distal portion of the device terminates at a distal end comprising a disc shaped distal end The disc shaped distal end comprises a first semi circular shaped elec tro
10. lar veins of each vertebral level US 8 348 946 B2 13 The vertebral arterial system includes the segmental arter ies of the vertebral column which supply anterior and poste rior radicular arteries of the various vertebral levels In tho racic and lumbar regions segmental arteries include the posterior intercostal subcostal and lumbar arteries which arise from posterior aspect of the aorta The blood supply to the spinal column is derived from the segmental arteries which supply two networks one feeds the bony elements of the vertebrae the paraspinal muscles and the extradural space and the other an inner network nourishes the spinal cord itself Extending from the aorta the segmental arteries hug the perimeter of the vertebral bodies of the vertebrae giving off paravertebral anastomoses prevertebral anastomoses and a main dorsal branch as they approach the neural foramina This main dorsal branch continues posteriorly below the transverse process of the vertebrae supplying the bone ofthe posterior elements of the vertebrae and the paraspinal muscles Shortly after its origin the dorsal branch gives off a spinal branch which supplies the anterior radicular artery and anterior segmental medullary artery which ultimately sup plies the anterior spinal artery The spinal branch also sup plies a branch to the vertebral body and dura mater and the posterior radicular artery which ultimately supplies the pos terior spinal art
11. pe mn Rm AB IE a Di U S Patent Power Watts Saline Flow Rate cc min Jan 8 2013 Sheet 4 of 15 US 8 348 946 B2 RE BE SOOT AWN NOTA DUAE 3 THEE rei eee nn nna i ees Bipolar Pow er e 200 Watt Setting Bipolar Power 100 Watt Setting BM H T 100 200 300 400 500 600 700 800 900 1900 Load pu FIG 4 20 40 60 80 100 7120 440 180 180 200 Power Setting Watts E E High Oy i Medium p FIG 5 US 8 348 946 B2 Sheet 5 of 15 Jan 8 2013 U S Patent 9 Old revere seme MANARE 10005 U S Patent Jan 8 2013 Sheet 6 of 15 US 8 348 946 B2 120 7 US 8 348 946 B2 Sheet 7 of 15 Jan 8 2013 U S Patent US 8 348 946 B2 Sheet 8 of 15 Jan 8 2013 U S Patent cta e REESE AAA TT Es A ARTT CER we 257 4 AL 4 Pi zei US 8 348 946 B2 Sheet 9 of 15 Jan 8 2013 U S Patent s TE U S Patent Jan 8 2013 Sheet 10 of 15 US 8 348 946 B2 equ SO lida kig A or IE 155 198 158 Bh 2
12. provided by various structures Fluid 24 from the fluid source 22 15 first communicated through lumen 29 of delivery tubing 28 As shown in FIG 8 fluid 24 then feeds into a lumen 156 of a size reduction bushing 154 located within handle 104 and then into lumen 152 of tubing 150 which is contained in the lumen 124 of shaft 102 as shown in FIG 12 From lumen 152 of tubing 150 fluid 24 then flows through bore 140 then into bore 144 and is expelled from holes 146a 1465 In the present embodiment which makes use of a peristaltic pump 32 a special pump tubing segment 182 as shown in FIG 7 designed to operate specifically with the peristaltic pump 32 20 40 45 55 65 12 may be spliced in between portions of delivery tubing 28 and connected thereto using barbed fluid line connectors 180 at each end thereof The relationship between the material for electrodes 114a 1145 and their surfaces and fluid 24 throughout the various embodiments should be such that the fluid 24 wets the surface ofthe electrodes 114a 1145 Contact angle 0 is quantita tive measure of wetting of a solid by a liquid It is defined geometrically as the angle formed by a liquid at the three phase boundary where a liquid gas and solid intersect In terms of the thermodynamics of the materials involved con tact angle 0 involves the interfacial free energies between the three phases given by the equation cos 974sy sr where
13. second Stated another way for expediency the tissue should be heated sufficiently to shrink the collagen in the range between and including about 1 second to 10 seconds after RF activa tion Fluid 24 in addition to providing an electrical coupling between the device 30a and tissue 200 cools and lubricates surface 202 of tissue 200 to inhibit electrodes 114a 1146 from sticking to tissue 200 Depending on the amount of fluid atthe distal end of device 30a and the tissue treatment site the fluid coupling 204 may comprise a single coupling which encompasses the distal end of the device 30a or a plurality of discrete couplings which are located on each side of the device closest to holes 146a 1465 The fluid coupling for device 30a may also comprise a conductive fluid bridge between electrodes 114a 1145 which rests on surface 202 of tissue 200 and forms a shunt between electrodes 114a 1146 Given this scenario a certain amount of RF energy may be diverted from going into tissue 200 and actually pass between electrodes 114a 1145 via the conduc tive fluid bridge This loss of RF energy may slow down the process oftreating the tissue However for device 30a having this coupling located between the opposing corners 148a and 1486 and or opposing corners 149a and 1496 of electrodes 114a 1146 respectively may be desirable as the tissue cent to these corners may heat faster or get hotter than other tissue being treated due to the ele
14. the vertebra deforming In this manner the blood vessel may be compressed at which time the compressed portion of the vessel may be heated sufficiently to occlude the blood vessel after the surgical device is removed from the blood vessel FIG 17 shows how the distal portion 106 of device 30a and similarly for devices 305 304 may be oriented for use with the longitudinal axis of shaft 102 vertically oriented and the distal end of device 30a facing a tissue treatment site In other embodiments device 30a may be used with the longi tudinal axis of shaft 102 horizontally oriented or at any orientation between vertical and horizontal FIG 17 shows device 30a and tissue 200 prior to treatment thereof As shown tissue 200 comprises a blood vessel 220 and more specifically an epidural vein Underlying blood vessel 220 is a ligament 230 and more specifically a longi tudinal ligament of the spine Underlying ligament 230 is a vertebra 232 and more specifically a vertebral body of the vertebra 232 FIG 18 shows device 30a applied to tissue 200 with suf ficient force and pressure applied to device 30a by the user thereof to press a portion of the blood vessel 220 against the supporting spine structure here ligament 230 and vertebra 232 to provide a compressed portion of the blood vessel 220 In certain embodiments device 30a may include a feedback mechanism such as a force or pressure gauge which alerts the user of the device when suf
15. 1145 at corner 1495 thereof In this manner fluid may be provided to the locations of electrodes 114a 1145 and tissue expected to have the greatest need for the fluid for device 30a to function most properly i e the electrode corners and tissue adjacent thereto Also in this manner fluid from holes 146a 1466 may be provided to the semi circular shaped side perim eter 151a 1515 of electrodes 114a 1145 As shown in FIG 12 the semi circular shaped perimeter 151a 1515 of elec trodes 114a 1145 is exposed to tissue and extends circum ferentially around a substantial portion of the distal end of device 30a As shown the semi circular shaped perimeter 151a of electrode 114a extends from corner 148a to corner 149a of electrode 114a and the semi circular shaped perim eter 1516 of electrode 1145 extends from corner 1485 10 corner 1495 of electrode 1145 In other embodiments as shown in FIGS 15 and 16 the semi circular shaped side perimeter 151a 1515 of electrodes 114a 1145 for device 30d is covered by an electrical insula tion preferably provided by outer housing portion 112 to eliminate the semi circular shaped perimeter 151a 1515 of electrodes 114a 1145 from being used to treat tissue As shown the semi circular shaped perimeter 151a 1515 of electrodes 114a 1145 is covered by a ring shaped portion of outer housing portion 112 During use of device 30a fluid 24 from fluid source 22 is communicated through a fluid passage which
16. 204560 Al 8 2010 Salahich etal 2010 0241178 Al 9 2010 Tilson etal 2010 0312259 Al 12 2010 Houser et al 2010 0331883 Al 12 2010 Schmitz et al FOREIGN PATENT DOCUMENTS SU 1161093 6 1985 WO WO 02060523 8 2002 OTHER PUBLICATIONS Palanker et al Electrosurgery with Cellular Precision IEEE Trans actions on Biomedical Engineering Feb 2008 vol 55 No 2 p 838 841 McCauley Genard Understanding Electrosurgery MC 55 049 001 Rev 2 2010 16 pages Bovie Medical Corporation Clearwater FL United States International Search Report and Written Opinion dated Aug 29 2008 issued in related International Patent Appln No PCT US08 057815 European Search Report dated Mar 1 2010 issued in related Euro pean Patent Appln No 08744175 4 2305 cited by examiner US 8 348 946 B2 Sheet 1 of 15 Jan 8 2013 U S Patent FIG 1 Lae d i j H 4 US 8 348 946 B2 Sheet 2 of 15 Jan 8 2013 U S Patent Tann ey 2222 ETE EEE DZS Jed 5 ww ERE md M US 8 348 946 B2 Sheet 3 of 15 Jan 8 2013 U S Patent Ti prs Meus C 1 3 1 4 4 4 t 1 1 1 k x x sb RR AR eM P ER MEN
17. United States Patent US008348946B2 12 19 Patent No US 8 348 946 B2 McChurken et al 45 Date of Patent Jan 8 2013 54 SURGICAL DEVICES AND METHODS OF 5 460 629 A 10 1995 Shlain et al USE THEREOF 5 484 435 A 1 1996 Fleenor et al 6 004 269 A 12 1999 Crowley et al 6 053 937 4 2000 Edwards et al 75 Inventors Michael E McClurken Durham NH 6 149 646 11 2000 West Ir et al US Roger D Greeley Portsmouth 6 485 490 B2 11 2002 Wampler et al NH US Brian M Conley South Continued Berwick ME US FOREIGN PATENT DOCUMENTS 73 Assignee Medtronic Advanced Energy LLC Minneapolis MN US JP 2003079633 3 2003 Continued Notice Subject to any disclaimer the term of this patent is extended or adjusted under 35 OTHER PUBLICATIONS U S C 154 b by 0 days Salameh et al An Animal Tissue Model Study to Clarify and Inves 21 Appl No 13 494 574 tigate Endoscopic Tissue Coagulation by Using a New Monopolar Device Gastrointestinal Endoscopy Jan 2004 vol 59 No 1 p 22 Filed Jun 12 2012 107 112 65 Prior Publication Data Continued US 2012 0253343 A1 Oct 4 2012 Primary Examiner Lee S Cohen M Assistant Examiner Khadijeh Vahdat Related U S Application Data 74 Attorney Agent or Firm Sterne Kessler Goldstein 62 Division of application No 12 053 030 on amp Fox PL L C 21 2008 now Pat No 8 216 233 57 ABSTRACT 60 Provisional application
18. and or weld ing the opposite internal surfaces of the lumen together by collagen welding to inhibit a blood flow through the vessel after the surgical device is removed from the blood vessel The supporting spine structure against which the blood vessel is compressed comprises one or more vertebra of the spine and may further comprise the vertebral body of the vertebra The vertebra may comprise one of the cervical ver tebrae thoracic vertebrae or lumbar vertebrae In addition to the vertebrae the support structure may also comprise a spi nal ligament such as the anterior longitudinal ligament or the posterior longitudinal ligament or an intervertebral disc Depending on the type of procedure the supporting spine structure may further comprise an anterior side of the verte bral body of the vertebra or a lateral anterior side of the vertebral body of the vertebra which would be encountered during an anterior approach For a posterior approach the supporting spine structure may further comprise a posterior 20 25 30 35 40 45 50 55 60 65 14 side ofthe vertebral body of the vertebra or a lateral posterior side of the vertebral body of the vertebrae The anterior or posterior approach may be part of an endoscopic spine sur gery laparoscopic spine surgery or open spine surgery Due to the rigidity of the vertebra and stability of the vertebrae the blood vessel may be pressed against the verte bra without
19. as an electrical insulator polytet rafluoroethylene is preferred because it is hydrophobic and thus inhibits fluids present during surgery from settling thereon provides good are resistance and provides a low coefficient of friction for reduced tissue sticking As shown in FIG 12 housing outer portion 112 electrically insulates electrodes 114a 1145 from metal shaft 102 As shown in FIGS 11 and 12 housing outer portion 112 com prises a proximal cylindrical portion 118 and a distal cylin drical portion 120 Proximal cylindrical portion 118 has a slightly small outer diameter than distal cylindrical portion 120 which creates a rim 122 there between For assembly proximal cylindrical portion 118 provides a connector por tion for connecting housing outer portion 112 to shaft 102 As shown in FIG 12 the outside diameter of proximal cylindri cal portion 118 is configured to extend into lumen 124 of shaft 102 and fit with the inside diameter of shaft 102 with rim 122 in contact with the distal end 110 of shaft 102 The outside diameter of proximal cylindrical portion 118 may be config ured to fit with the inside diameter of shaft 102 to form a slip fit in which case adhesive or another bonding agent will be employed between cylindrical portion 118 and shaft 102 to provide a secure connection or a press interference fit which would not require the use of a separate bonding agent As shown in FIGS 11 and 12 housing inner portion 116 e
20. body during surgery particularly open surgery and minimally invasive surgery such as laparoscopic surgery BACKGROUND A dry tip electrosurgical device such as a Bovie pencil can cause the temperature of tissue being treated to rise signifi cantly higher than 100 Celsius resulting in tissue desicca tion tissue sticking to the electrodes tissue perforation char formation and smoke generation Furthermore certain surgical devices are too large to be used in confined surgical spaces and or are simply ineffective in treating tissue such as to inhibit blood loss More recently fluid assisted electrosurgical devices have been developed which use saline to inhibit undesirable effects such as tissue desiccation electrode sticking smoke produc tion and char formation during the treatment of tissue How ever too much saline can provide too much electrical disper sion and cooling at the electrode tissue interface This reduces the temperature of the tissue being treated and in turn can result in a longer treatment time to achieve the desired tissue temperature for treatment of the tissue Long treatment times are undesirable for surgeons since it is in the best interest of the patient physician and hospital to perform surgical procedures as quickly as possible In light of the above there is a need for devices and meth ods which address the foregoing concerns SUMMARY OF THE INVENTION The invention in one embodiment provides
21. close up view of a distal portion of the device of FIG 7 and tissue FIG 18 is a close up view of a distal portion of the device of FIG 7 pressing against tissue FIG 19 is a close up view of a distal portion of the device of FIG 7 being used to treat tissue and FIG 20 is a close up view of a distal portion of the device of FIG 7 removed from treated tissue DETAILED DESCRIPTION Throughout the description like reference numerals and letters indicate corresponding structure throughout the sev eral views Also any particular feature s of a particular exemplary embodiment may be equally applied to any other exemplary embodiment s of this specification as suitable In other words features between the various exemplary embodi ments described herein are interchangeable as suitable and not exclusive From the specification it should be clear that any use of the terms distal and proximal are made in reference from the user of the device and not the patient The inventions disclosed herein provide devices systems and methods for treating tissue during a surgical procedure These inventions are particularly useful for procedures where it is desirable to shrink coagulate and seal tissue against bloodloss for example by shrinking lumens of blood vessels e g veins arteries The invention will now be discussed with reference to the figures with FIG 1 showing a front view of one embodiment ofa system ofthe present
22. ctrode configuration In such a case having the fluid coupling 204 at these locations may provide for more balanced heating and treating of tissue 200 Consequently it may be desirable to provide fluid 24 from device 30a in such a quantity that a small portion of the fluid boils to dissipate heat from the tissue while at the same time the fluid diverts a certain amount of RF energy from going into tissue 200 at locations which may heat faster or get hotter than other tissue being treated FIG 20 shows device 30a removed from tissue 200 with the blood vessel 220 sealed against blood loss and blood flow there through As established above the bipolar devices of the present invention inhibit such undesirable effects of tissue desicca tion electrode sticking char formation and smoke genera tion and thus do not suffer from the same drawbacks as prior art dry tip electrosurgical devices The use of the disclosed devices can result in significantly lower blood loss during surgical procedures Such a reduction in blood loss can reduce or eliminate the need for blood transfusions and thus the cost and negative clinical consequences associated with blood transfusions such as prolonged hospitalization While a preferred embodiment ofthe present invention has been described it should be understood that various changes adaptations and modifications can be made therein without departing from the spirit ofthe invention and the scope ofthe appended c
23. de and a second semi circular shaped electrode The device may further comprise a fluid delivery passage being connectable to a fluid source of fluid and at least one fluid exit in fluid communication with the fluid delivery passage Inanother embodiment the invention provides a method of treating tissue having a blood vessel during spine surgery with the method comprising pressing a portion of the blood vessel against a supporting spine structure with a surgical device to provide a compressed portion of the blood vessel and heating the compressed portion of the blood vessel with the surgical device sufficiently to occlude the blood vessel after the surgical device is removed from the blood vessel In certain embodiments the supporting spine structure com prises a vertebra and more particularly a vertebral body of the vertebra Inanother embodiment the invention provides a method of treating tissue having a blood vessel during surgery with the method comprising pressing a portion of the blood vessel against a bone structure with a surgical device to provide a compressed portion ofthe blood vessel and heating the com pressed portion of the blood vessel with the surgical device sufficiently to occlude the blood vessel after the surgical device is removed from the blood vessel In another embodiment the invention provides an electri cally powered surgical device to be used during a surgical procedure with the device comprising an aperture f
24. desiccation electrode sticking smoke production and char formation while at the same time pro viding a fluid flow rate Q at a corresponding RF power setting which is not so great as to provide too much fluid and associated electrical dispersion and cooling at the electrode tissue interface While not being bound to a particular theory more detailed discussion on how the fluid flow rate interacts with the radio frequency power modes of heat transfer from the tissue fractional boiling of the fluid and various control strategies may be found in U S Publication No 2001 0032002 published Oct 18 2001 and assigned to the assignee ofthe present invention and hereby incorporated by reference in its entirety to the extent it is consistent As shown electrosurgical unit 14 has been configured to increase the fluid flow rate Q linearly with an increasing RF power setting P for each of three fluid flow rate settings of low medium and high corresponding to Q and respectively Conversely electrosurgical unit 14 has been configured to decrease the fluid flow rate Q linearly with a decrease RF power setting for each of three fluid flow rate settings of low medium and high corresponding to Qz and respectively As shown Qz and can be expressed as a function ofthe RF power setting chang ing exemplary proportionality constants as follows 0 0 1 0 1286 0 1571
25. e X axis FIG 6 15 a block diagram showing one embodiment of how the electrosurgical unit processes the inputs of RF power setting P and the fluid flow rate setting either Q to control the pump speed FIG 7 is an isometric view of an assembly of an exemplary electrosurgical device according to the present invention FIG 8 is an isometric view of the inner components of the handle with the handle removed US 8 348 946 B2 3 FIG 9 is a side view of a handle portion of the device of FIG 7 assembled with various components FIG 10 is a close up side view of a button and handle portion of the device of FIG 7 assembled with various com ponents FIG 11 is an exploded view ofa distal portion ofthe device of FIG 7 FIG 12 is a close up longitudinal cross sectional view of a distal portion of the device of FIG 7 FIG 13 is a close up longitudinal cross sectional view of a distal portion of an alternative exemplary electrosurgical device according to the present invention FIG 14 is a close up longitudinal cross sectional view of a distal portion of an alternative exemplary electrosurgical device according to the present invention FIG 15 is an isometric view of a distal portion of an alternative exemplary electrosurgical device according to the present invention FIG 16 is a close up longitudinal cross sectional view of the distal portion of the device of FIG 15 taken along line 16 16 and FIG 17 is a
26. ebra 13 The method according to claim 9 wherein the supporting spine structure further comprises a lateral posterior side of the vertebral body of the vertebra 14 The method according to claim 1 wherein the supporting spine structure comprises a spinal ligament and a vertebra 15 The method according to claim 1 wherein the spine surgery further comprises a discectomy 16 The method according to claim 1 wherein the spine surgery further comprises a spinal fusion
27. er turning the electrosurgical unit 14 on the RF power setting display 44 is used to display the RF power setting numerically in watts Preferably the power setting display comprises a liquid crystal display LCD Addition US 8 348 946 B2 5 ally this display 44 is used to display errors in which case display 44 will show Err and blink alternately with a special error code number s The RF power selector comprises RF power setting switches 46a 46b which are used to select the RF power setting Pushing the switch 46a increases the RE power set ting while pushing the switch 465 decreases the RF power setting RF power output may be set in 5 watt increments in the range of 20 to 100 watts and 10 watt increments in the range of 100 to 200 watts Additionally electrosurgical unit 14 includes an RE power activation display 74 comprising an indicator light which illuminates when RF power is activated Switches 46a 466 may comprise membrane switches In addition to having a RF power setting display electro surgical unit 14 further includes a fluid flow rate setting dis play Flow rate setting display comprises three indicator lights 50a 505 and 50c with a first light 50a corresponding to a fluid flow rate setting of low a second light 505 correspond ing to a fluid flow rate setting of medium intermediate and a third light 50c corresponding to a flow rate setting of high Oneofthese three indicator lights will illuminate
28. eries During a posterior discectomy the devices of the present invention may be more particularly used by a surgeon to seal veins of the posterior external vertebral venous plexus pos terior internal vertebral epidural venous plexus and anterior internal vertebral epidural venous plexus prior to entering the intervertebral disc space Alternatively during an anterior discectomy the devices of the present invention may be more particularly used by a surgeon to seal veins of the anterior external vertebral venous plexus and segmental arteries par ticularly the anterior and lateral anterior portions adjacent the vertebral bodies During a discectomy blood vessels are often cut ruptured or otherwise severed These blood vessels bleed and the resulting blood can flow into the tissue treatment site making visibility more difficult and prolonging the procedure A method of the present invention may be used to seal such vertebral blood vessels against blood loss before the vessels are cut rupture or are otherwise severed This method involves pressing a portion of the blood vessel against a supporting spine structure with a surgical device such as the devices of the present invention to provide a compressed portion of the blood vessel and heating the compressed por tion ofthe blood vessel with the surgical device sufficiently to occlude the blood vessel e g by shrinking the vessel and the Iumen by shrinkage ofthe collagen in the vessel
29. ficient force pressure is applied to vessel 220 In other embodiments the feedback mechanism may comprise a light which activates As shown electrodes 114a 1145 of device 30a are spaced adjacent tissue surface 202 of tissue 200 by the width of distal spacer portion 126 of housing inner portion 116 FIG 19 shows device 30a in use with fluid 24 expelled from holes 146a 1465 that flows distally to electrodes 114a 1145 to provide a localized fluid coupling 204 between sur face 202 of tissue 200 and electrodes 114a 1145 Preferably fluid 24 couples between the electrodes 114a 1145 and the tissue 200 at both the perimeter 151a 1515 of electrodes 114a 1145 and flat semi circular shaped electrode portions 138a 1385 of the electrodes 114a 1145 located at the distal end of device 30a At the same time RF electrical energy power shown by electrical field lines 206 is provided to tissue 200 at tissue surface 202 and below tissue surface 202 into tissue 200 through fluid 24 Electrodes 114a 1145 are connected to electrosurgical unit 14 to provide RE energy power and form an alternating cur rent electrical field in tissue 200 In the presence of alternating current the electrodes 114a 1145 alternate polarity between positive and negative charges with current flow from the positive to negative charge Without being bound to a particu lar theory heating of the tissue is performed by electrical resistance heating That is the temperature of t
30. h 162 on device 30 as shown in FIG 1 ora footswitch not shown A pullout drawer 76 is located under the electrosurgical unit 14 where the user of electrosurgical unit 14 may find a short form of the user s manual FIG 3 shows the rear panel of electrosurgical unit 14 The rear panel of the electrosurgical unit 14 includes a speaker 60 and a volume control knob 62 to adjust the volume ofthe tone that will sound when the RF power is activated RF power activation tone The volume ofthe RF power activation tone 15 increased by turning the knob clockwise and decreased by turning the knob counterclockwise However the electrosur gical unit 14 prevents this tone from being completely silenced Rear panel of electrosurgical unit 14 also includes a power cord receptacle 64 used to connect the main power cord to the electrosurgical unit 14 and an equipotential grounding lug connector 66 used to connect the electrosurgical unit 14 to earth ground using a suitable cable The rear panel also includes a removable cap 68 for the installation of a bipolar footswitch socket connectable to an internal footswitch cir 20 25 30 35 40 45 50 55 60 65 6 cuit of electrosurgical unit 14 so that the RF power may be activated by a footswitch in addition to a handswitch of device 30 Additionally the rear panel also includes a fuse drawer 70 which includes which contains two extra fuses consistent with the line voltage Finally
31. he tissue increases as a result of electric current flow through the tissue with the electrical energy being absorbed from the voltage and transformed into thermal energy 1 heat via acceler ated movement of ions as a function of the tissue s electrical resistance Heating the compressed portion of blood vessel 220 with device 30a is sufficient to at least partially occlude blood vessel 220 to inhibit blood flow through the vessel 220 after device 30a is removed from vessel 220 Here this is per US 8 348 946 B2 15 formed by heating vessel 220 sufficiently to shrink the col lagen in vessel 220 thereby shrinking the vessel 220 and the Iumen 222 of vessel 220 This is also performed by apply sufficient heating and pressure to the compressed portion of vessel 220 to weld the opposing internal surfaces 224 and 226 of the lumen 222 together here by collagen welding The time to shrink tissue containing Type I collagen such as blood vessels is generally dependent on temperature For example Type I collagen shrinks at an exposure time of about 0 01 seconds when exposed to a temperature of about 85 C at an exposure time of about 1 second when exposed to a temperature of about 75 C at an exposure time of about 10 second when exposed to a temperature of about 70 C and at an exposure time of about 15 minutes when exposed to a temperature of about 65 C An exemplary target tempera ture time for tissue heating is about 75 C with
32. ice comprises a bipolar electrosur gical device 4 The method according to claim 3 wherein the bipolar electrosurgical device is configured to treat tissue in a presence of radio frequency power and a fluid provided simultaneously from a distal portion of the device 5 The method according to claim 1 further comprising heating the compressed portion of the blood vessel in a range of at least about 65 Celsius to about 85 Celsius 6 The method according to claim 1 further comprising heating the compressed portion of the blood vessel in a range of at least about 7 Celsius to about 75 Celsius 7 The method according to claim 1 further comprising heating the compressed portion of the blood vessel in a range of about 70 Celsius to about 100 Celsius 8 The method according to claim 1 wherein the supporting spine structure comprises a vertebra 9 The method according to claim 8 wherein the supporting spine structure further comprises a vertebral body ofthe vertebra 10 The method according to claim 9 wherein the supporting spine structure further comprises an anterior side of the vertebral body of the vertebra 11 The method according to claim 9 wherein the supporting spine structure further comprises a lateral anterior side of the vertebral body of the vertebra 12 The method according to claim 9 wherein the supporting spine structure further comprises a posterior side of the vertebral body of the vert
33. ings and an explanation of the operation of switch assembly 162 may be found in U S Publication No 2005 0090816 published Apr 28 2005 and assigned to the assignee of the present invention and hereby incorporated by reference in its entirety to the extent it is consistent During use of device 30a blood and coagulum may deposit in a narrow gap 170 between button 164 and handle 104 As best shown in FIG 10 button 164 is located in aperture 166 of handle 104 which is defined by a perimeter wall 168 As shown button 164 includes a plurality of apertures 163 in the sides thereof Apertures 163 reduce the surface area of the side walls 165 of button 164 adjacent to the perimeter wall 168 of handle portions 104a 1045 Consequently due to the reduced surface area of the side walls 165 of button 164 button 164 is less apt to adhere and stick to handle portions 104a 1045 by virtue of the blood and coagulum when the depression force is removed from button 164 As best shown in FIG 11 device 30a has a disc shaped distal end comprising two bipolar electrodes 114a 1145 An insulator housing assembly comprising housing outer portion 112 and housing inner portion 116 secures the electrodes 114a 114 to device 30a Housing outer portion 112 and housing inner portion 116 comprise an electrically insulative material preferably a polymer and more preferably a fluori nated polymer such as polytetrafluoroethylene PTFE In addition to functioning
34. invention having an electrosurgical unit 14 in combination with a fluid source 22 and a handheld electrosurgical device 30 FIG 1 shows a movable cart 2 having a chassis 4 which is provided with four wheels 6 for easy transportation The chassis 4 carries a vertical support member 8 comprising a hollow cylindrical post to which a storage basket 10 may be fastened and used to store the electrosurgical unit s user manual as well as additional unused devices Furthermore the support member 8 carries a platform 12 comprising a pedestal table to provide a flat stable surface for location of the electrosurgical unit 14 As shown cart 2 further comprises a fluid source carrying pole 16 having a height which may be adjusted by sliding the carrying pole 16 up and down within the support member 8 and thereafter secured in position with a set screw On the top 20 25 30 35 40 45 50 55 60 65 4 of the fluid source carrying pole 16 is a cross support 18 provided with loops 20 at the ends thereof to provide a hook for carrying fluid source 22 Returning to FIG 1 fluid source 22 comprises a bag of fluid from which the fluid 24 flows through a drip chamber 26 afterthe bag is penetrated with a spike located at the end ofthe drip chamber 26 Thereafter fluid 24 flows through flexible delivery tubing 28 to handheld electrosurgical device 30 Preferably the fluid delivery tubing 28 is made from a poly mer material As shown in
35. ition to FIG 8 switch assembly 162 is shown in FIGS 9 and 10 As best shown in FIG 10 switch assembly 162 comprises a push button 164 and a dome switch 172 having two electrical contacts The contacts preferably com prise upper and lower contacts disposed on a platform 174 in overlying relationship Preferably the upper contact com prises a dome shaped configuration overlying and spaced from the lower contact which is flat Preferably the contacts are spaced from one another by virtue of the domed configu ration of the upper contact when the button 164 is in an undepressed position thus creating an open control circuit relative to switch 172 However when the top of button 164 is pressed and the upper contact is correspondingly pressed into a depressed position the upper contact comes into contact with the lower contact thus closing the hand switch control US 8 348 946 B2 9 circuit The presence of the closed control circuit is then sensed by electrosurgical unit 14 which then provides power to the electrodes 114a 1146 When a depression force is removed from the upper con tact the contact returns to its undepressed domed position as a result of its resiliency or elastic memory thus returning button 164 to its undepressed position and reopening the hand control circuit The presence of the open control circuit is then sensed by electrosurgical unit 14 which then stops providing power to electrodes 114a 1145 More detailed draw
36. laims The scope of the invention should there 20 40 45 50 16 fore be determined not with reference to the above descrip tion but instead should be determined with reference to the appended claims along with their full scope of equivalents Furthermore it should be understood that the appended claims do not necessarily comprise the broadest scope of the invention which the Applicant is entitled to claim or the only manner s in which the invention may be claimed or that all recited features are necessary publications and patent documents cited in this appli cation are incorporated by reference in their entirety for all purposes to the extent they are consistent What is claimed is 1 A method of treating tissue having a blood vessel during spine surgery the method comprising providing an electrically powered surgical device having a planar distal end pressing a portion of the blood vessel against a supporting spine structure with the planar distal end of the device to provide a compressed portion of the blood vessel and heating the compressed portion ofthe blood vessel with the surgical device sufficiently to occlude the blood vessel after the electrically powered surgical device is removed from the blood vessel 2 The method according to claim 1 wherein the electrically powered surgical device comprises an elec trosurgical device 3 The method according to claim 2 wherein the electrosurgical dev
37. lectrically insulates electrodes 114a 1145 from one another by providing a spacer there between In particular housing inner portion 116 comprises a distal spacer portion 126 dis posed between electrodes 114a and 1146 For assembly housing inner portion 116 further comprises a proximal cylin drical portion 128 for connecting housing inner portion 116 to housing outer portion 112 As shown in FIG 12 the outside 20 25 30 35 40 45 50 55 60 65 10 diameter of proximal cylindrical portion 128 is configured to extend into inner bore 130 of housing outer portion 112 and fit with the diameter of bore 130 with the distal cylindrical portion 120 of housing outer portion 112 providing a collar around housing inner portion 116 and electrodes 114a 1145 The outside diameter of proximal cylindrical portion 128 may beconfigured to fit with the diameter of bore 130 to form a slip fit in which case adhesive or another bonding agent will be employed between cylindrical portion 128 and housing outer portion 112 to provide a secure connection or a press inter ference fit which would not require the use of a separate bonding agent In addition to the above as best shown in FIG 11 proximal cylindrical portion 128 of housing inner portion 116 is pro vided with two opposing flat surfaces 132a 1326 formed thereon to create two localized gaps 134a 1345 as shown in FIG 12 between housing outer portion 112 and housing inne
38. ormed in the device the aperture having a button therein to activate the device the aperture defined by a perimeter wall surrounding the button a narrow gap between the button and the perimeter wall the narrow gap open to a flow of fluid therein from the surgical procedure the fluid comprising blood and the button having at least one side closely adjacent the perimeter wall surrounding the button the at least one side of the button having at least one aperture formed therein to inhibit the button from adhering with the perimeter wall by the blood Itis understood that the specific features described in these embodiments can be rearranged among the various embodi ments to provide devices apparatus systems and methods that fall within the scope of this disclosure BRIEF DESCRIPTION OF THE DRAWINGS FIG 11sa front view of one embodiment ofa system ofthe present invention having an electrosurgical unit in combina tion with a fluid source and handheld electrosurgical device FIG 2 isa front perspective view of the electrosurgical unit of FIG 1 FIG 3 is a rear view of the electrosurgical unit of FIG 1 FIG 4 is a graph of the RF power output P versus imped ance Z for the electrosurgical unit of FIG 1 FIG 5 is graph showing three relationships of fluid flow rate of saline at high medium Q and low Q in units of cubic centimeters per minute cc min on the Y axis and the RF power setting in units of watts on th
39. osus to swell and herniate pushing through a weak spot in the annulus fibrosus membrane of the disc and into the spinal canal Consequently all or part of the nucleus pulposus material may protrude through the weak spot causing pressure against surrounding nerves which results in pain and immobility Where a damaged intervertebral disc must be removed fromthe patient as part ofa discectomy and subsequent fusion of vertebral bodies of the superior and inferior vertebrae the devices ofthe present invention may be particularly useful to shrink and seal blood vessels of the vertebral venous and or arterial systems The vertebral venous system includes any of four intercon nected venous networks surrounding the vertebral column These are known as the anterior external vertebral venous plexus the system around the vertebral bodies the posterior external vertebral venous plexus the system around the ver tebral processes the anterior internal vertebral epidural venous plexus the system running the length ofthe vertebral canal anterior to the dura and the posterior internal vertebral epidural venous plexus the system running the length ofthe vertebral canal posterior to the dura with the latter two constituting the epidural venous plexus The veins of the exterior vertebral venous plexus communicate with the veins of the interior vertebral venous plexus through intervertebral veins and anterior and posterior segmental medullary radicu
40. ovided in the electrically insulative material used for housing outer portion 112 and are located on the distal portion of device 30a proximal to the distal end of the device In this manner holes 146a 1465 are configured to inhibit clogging during use of the device 30a In other words since housing outer portion 112 is not electrically conductive and does not function as an electrode tissue and blood coagulum are less apt to stick to housing outer portion 112 Also since holes 146a 1466 are located on the distal portion of device 30a proximal to the distal end of the device holes 146a 1465 are less apt to be exposed directly to the bloody field generally located at the distal end of device 30a In the event holes 146a 1465 and bore 144 become clogged holes 146a 1465 and bore 144 may be unclogged and cleaned by inserting a pin type structure into one of the holes and bore 144 and extending the pin completely through device 30a and exiting the pin from the other hole In this manner the matter clogging holes 146a 1465 and bore 144 may be pushed and removed there from by the pin Also as shown in FIG 11 holes 146a 1465 are located on opposing sides of device 30a Hole 146a is provided adjacent and closest to electrode 114a at corner 148a thereof and adjacent and closest to electrode 1145 at corner 1485 thereof Hole 1465 is provided adjacent and closest to electrode 114a at corner 149a thereof and adjacent and closest to electrode
41. r portion 116 through which legs 136a 1365 of elec trodes 114a 1145 may extend to be connected with wire conductors 158a 1585 of insulated wires 160a 1605 Returning to FIG 11 legs 136a 1366 of electrodes 114a 1145 extend proximally from two semi circular shaped elec trode portions 138a 1385 located at the distal end of device 30a and having the same size and shape In this manner the current density exhibited by the electrodes relative to one another will be substantially uniform Also as shown the semi circular electrode portions are mirror images of each other and each comprises the shape of about half of a circle Electrodes 114a 1145 preferably comprise an electrically conductive metal which is also preferably non corrosive preferred material is stainless steel Other suitable metals include titanium gold silver and platinum As shown in FIG 12 the distal end of device 30a is planar flat and perpendicular to the longitudinal axis of shaft 102 In other embodiments as shown for example in FIG 13 the distal end of device 305 may be convex In still other embodi ments as shown for example in FIG 14 the distal end of device 30c may be concave Returning to FIG 12 housing inner portion 116 also includes a longitudinally oriented linear blind bore 140 and counter bore 142 centrally located within cylindrical portion 128 As shown the outside diameter of fluid delivery tubing 150 is configured to extend into co
42. s connectable to fluid source 22 preferably via a spike located at the end of drip chamber 26 as shown in FIG 1 anda cable 34 which is connectable to electrosurgical unit 14 which respectively provide fluid and RF power to distal portion 106 Inthis embodiment cable34 ofdevice 30a comprises three insulated wires 34a 345 34c as shown in FIG 8 connect able to electrosurgical unit 14 via three male plug connec tors 37a 376 37c The plug connectors 37a 375 37c are each assembled with wires 34a 345 34c and wire conductors 35a 35b 35c within a common plug housing 36 As best shown in FIG 8 which shows the inner components of the handle 104 with the handle 104 removed wire conductor 35a is directly connected preferably by welding to wire conductor 158a of insulated wire 160a which is distally connected to electrode 114a as discussed in greater detail below As also shown in FIG 8 wire conductor 355 of wire 345 first connects through hand switch assembly 162 before connecting preferably be welding to wire conductor 1585 of insulated wire 1605 which is distally connected to electrode 1145 as discussed in greater detail below Finally wire conductor 35c of wire 34c is connected to hand switch assembly 162 to alert electrosur gical unit 14 to provide power when the circuit for the switch assembly has been closed through depression of hand switch push button 164 preferably made of a rigid polymer such as polyacetal In add
43. ssignee of the present invention and hereby incorporated by reference in its entirety to the extent it is consistent Electrosurgical unit 14 can include a delay mechanism such as a timer to automatically keep the fluid flow on for several seconds after the RF power is deactivated to provide a post treatment cooling Electrosurgical unit 14 can also include a delay mechanism such as a timer to automatically turn on the fluid flow up to several seconds before the RF power is activated to inhibit the possibility of undesirable effects as tissue desiccation electrode sticking char forma tion and smoke production Electrosurgical unit 14 is particularly configured for use with bipolar devices With a bipolar device an alternating current is created between the first and second electrical poles ofthe device An exemplary bipolar electrosurgical device of the present invention which may be used in conjunction with electrosurgical unit 14 of the present invention is shown at reference character 30a in FIG 7 While various electrosur gical devices of the present invention are described herein with reference to use with electrosurgical unit 14 it should be understood that the description of the combination is for purposes of illustrating the system of the invention Conse quently it should be understood that while the electrosurgical devices disclosed herein may be preferred for use with elec 20 25 30 35 40 45 50 55 60
44. the rear panel includes a name plate 72 which may provide information such as the model number serial number nominal line voltages frequency cur rent and fuse rating information ofthe electrosurgical unit 14 The RF power output curve of electrosurgical unit 14 is shown in FIG 4 Impedance Z shown in units of ohms on the X axis and output power Po is shown in units of watts on the Y axis In the illustrated embodiment the bipolar electrosur gical power RF is set to 200 watts As shown in the figure for an RF power setting of 200 watts the output power will remain constant with the set RF power as long as the impedance Z stays between the low impedance cut off of 30 ohms and the high impedance cut off of 125 ohms Below an impedance Z of 30 ohms the output power will decrease as shown by the low impedance ramp Above an impedance Z of 250 ohms the output power will also decrease as shown by the high impedance ramp Electrosurgical unit 14 has also been configured such that the pump speed and therefore the throughput of fluid expelled by the pump is predetermined based on two input variables the RF power setting and the fluid flow rate setting In FIG 5 there is shown a relationship of fluid flow rate Q in units of cubic centimeters per minute cc min on the Y axis and the RF power setting in units of watts on the X axis The relationship has been engineered to inhibit undesirable effects such as tissue
45. unter bore 142 and fit with the diameter of counter bore 142 with the distal end of the tubing in contact with the bottom of the counter bore The outside diameter of fluid delivery tubing 150 may be config ured to fit with the diameter of counter bore 142 to form a press interference fit to provide a secure connection along with use of an adhesive or another bonding agent to provide a fluid tight seal between fluid delivery tubing 150 and housing inner portion 116 In addition to blind bore 140 and counterbore 142 housing inner portion 116 also includes a linear through bore 144 which perpendicularly intersects bore 140 at the distal end of bore 140 and extends through cylindrical portion 128 As shown bore 140 and bore 144 are in fluid communication with lumen 152 of fluid delivery tubing 150 which is ulti mately in fluid communication lumen 29 of fluid delivery tubing 28 In this manner bore 140 and bore 144 provide a T shaped fluid flow passage for fluid 24 provided from fluid delivery tubing 28 and 150 As shown in FIG 11 in order to have fluid from the fluid passage provided by bore 144 exit device 30a cylindrical portion 120 ofhousing outer portion 112 is provided with two through holes 146a 1465 which align with bore 144 and US 8 348 946 B2 11 provide fluid exits for fluid As shown bore 144 extends through housing inner portion 116 parallel to distal spacer portion 126 As best shown in FIG 11 holes 146a 1465 are pr
46. utput control unit In this manner the functional relationships between the radio fre quency power level and the flow of the fluid may be stored in the memory of the computer chip 45 While the functional relationships may be stored in the form of the foregoing equations they may also be stored as numerical data points as part of a database look up table As shown the input signals 41 are received and processed by computer chip 45 More specifically for example from the input signal received corresponding to the fluid flow rate setting of either Q or the computer chip 45 may first determine which ofthe above equations to apply After deter mining which equation to apply computer chip 45 may then apply the relationship to determine the output for flow of the fluid from the pump 32 based on the selected radio frequency power level Having determined this output the computer chip 45 then sends output signals 51 and 53 corresponding to the selected radio frequency power level and calculated out put for flow of the fluid from the pump 32 to the radio frequency generator 47 and pump controller 48 respectively Thereafter the pump controller 48 controls the speed of the pump drive shaft 55 by controlling the input voltage 59 to the pump motor 61 which rotates the drive shaft 55 More detailed drawings of exemplary electrosurgical unit 14 may be found in U S Publication No 2006 0149225 published Jul 6 2006 and assigned to the a
47. when a fluid flow rate setting is selected A fluid flow selector comprising flow rate setting switches 52a 52b and 52c are used to select or switch the flow rate setting Three push switches are provided with the first switch 52a corresponding to a fluid flow rate setting of low the second switch 525 corresponding to a fluid flow rate setting of medium intermediate and the third switch 52c correspond ing to a flow rate setting of high Pushing one of these three switches selects the corresponding flow rate setting of either low medium intermediate or high The medium or inter mediate flow rate setting is automatically selected as the default setting if no setting is manually selected Switches 52a 52b and 52c may comprise membrane switches Before starting a surgical procedure it is desirable to prime device 30 with fluid 24 Priming is desirable to inhibit RF power activation without the presence of fluid 24 A priming switch 54 is usedto initiate priming of device 30 with fluid 24 Pushing switch 54 once initiates operation of pump 32 for a predetermined time period to prime device 30 After the time period is complete the pump 32 shuts off automatically When priming of device 30 is initiated a priming display 56 comprising an indicator light illuminates during the priming cycle On the front panel the bipolar activation display 74 illumi nates when RF power 15 activated from the electrosurgical unit 14 either via a hand switc
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