3010 Service Manual, version 2.1
Contents
1. The stimulus verification circuitry monitors the integrity of the patient instrument circuit including continuity of the probe and cable W hen proper current is being delivered the amber INCOMPLETE STIMULATION light will go out It will flash at all other times i e broken cables disconnected cables poor ground poor probe contact etc Verification of stimulation can also be obtained by touching the forearm or wrist area of a test subject starting with a low current setting and increasing to a reasonable level up to 6 or 8 MA may be required due to the narrow pulse width of 0002 sec Use anon sterile probe for this procedure so that sterile probes will be available for surgery The unit may also be tested on an oscilloscope using a 1K precision resistor across the output The oscilloscope will then display the pulse amplitude directly in milliamperes 1 volt 1 mA T he active probe can be shorted to the indifferent electrode without damage to the circuitry Silverstein Facial Nerve M onitor Stimulator Service M anual version 2 1 Page 11 BATTERY CONDITION INDICATOR AND BATTERY CHARGING WARNING Check battery condition prior to and during use The monitor and stimulator circuits each have their own independent battery supply The monitor battery should be fully charged before use For full battery capacity charge for 36 hours before use or leave plugged in when not in use The yellow warning light will illuminate when approxi2. Voltage R egulator Supplies a constant 3 8 volts for the pulse generator and primary driver Pulse G enerator G enerates stimulator pulse train at specified frequency and width Driver Switches 9 volts pulse into 100 volt pulse e Adjustable Constant C urrent G enerator Stimulation current is user adjustable via switches on the surgical probe Relays drive a motorpot assembly which sets the output current level The constant current pulse is then generated by measuring the voltage drop across an internal load and varying the output voltage as needed If the voltage drop is too small the incomplete stimu lation light flashes to warn the operator that excess resistance exists Silverstein Facial N erve M onitor Stimulator Service M anual version 2 1 Page 20 2 0 MAINTENANCE SCHEDULE Detailed maintenance procedures are in sections 3 and 4 2 1 THE FOLLOWING ACTIONS MUST BE TAKEN AFTER EACH USE 1 Sterilize equipment 2 Recharge monitor batteries 3 Check stimulator batteries and replace if necessary 4 Check front panel controls 2 2 THE FOLLOWING ACTIONS MUST BE TAKEN EVERY THREE MONTHS 1 Check monitor calibration 2 Check stimulator calibration 3 Replace stimulator batteries 4 Clean the exterior with a water damp cloth 2 3 THE FOLLOWING ACTIONS MUST BE TAKEN EVERY YEAR 1 Unit should be returned to WR M edical Electronics every year for routine calibration 2 Replace Nickel cadmium monitor batteries BEE Sil
3. mately 30 minutes to 120 minutes of battery power remain depending on current ad justment activity Do not use instrument if FAIL light is illuminated The stimulator bat tery will last approximately 50 hours and must be replaced if the green light is out Do not use instrument without positive green indications To charge batteries plug wall mount charger into 115 volt wall receptacle and plug the small round connector into the back of the unit T he charge light should illuminate and will become dim as battery reaches fully charged level T he monitor and stimulator are disabled when the small battery charge connector is plugged in To replace the stimulator batteries simply open the small door on the rear panel Four size A A batter ies will be found inside INSTALLING THE CHEEK MUSCLE MOVEMENT SENSOR Thecheek muscle movement sensor isinserted into the mouth and is attached to the cheek of the in tubated patient on the same side as the intended surgical procedure T he side with the adjusting screw goes on the outside against the cheek The blade inside the mouth should angle upward to ward the eye between the gum and the oral mu cous on the inside of the cheek Bunch the cheek up in between the blades while pushing the sensor in tightly T he thumbscrew should be adjusted so the blades grasp the patient s cheek securely with alight pressure Excessive pressure may impair the response The sensor may be secured to the cheek Fig
4. 15006 15010 15014 15042 15048 15049 15079 15091 15095 15098 15103 15121 15146 15149 15163 16000 16005 16007 16009 16011 16013 16014 17026 17034 17038 17039 17040 17042 17043 17046 17048 17049 17050 17051 17052 17053 17054 17057 Component Conn Crimp 10 6 cond mol Decal Wall Mt Chgr S8 Br Decal Bright O range Decal Ser No Decal Batt Repl 58 Hdwr Bracket motorpot Hdwr Cardboard rect Hdwr Cardboard sq H dwr Elec Test Point Hdwr Knob chrome faced H dwr Lock washer int 4 Hdwr Nut 4 40 Hex Keps Hdwr Nut 8 32 Hex Keps Hdwr Screw Phil pan hd 4x1 4 Hdwr Screw pan hd 4 40x1 2 Hdwr Screw pan hd 8 32x1 2 Hdwr Stand off PSA 1 4 Audio alarm Display LCD Backlit Lamp LED green Lamp LEID red Lamp LED yellow Lamp neon amber Lamp neon clear Res 1 4w 270 ohm Res 1 4w 0 ohm jumper Res 1 4w 100 ohm CF Res 1 4w 100K ohm CF Res 1 4w 10K ohm CF Res 1 4w 150K ohm CF Res 1 4w 15K ohm CF Res 1 4w 1K ohm CF Res 1 4w 2 2K ohm CF Res 1 4w 2 2M ohm CF Res 1 4w 2 7K ohm CF Res 1 4w 220 ohm CF Res 1 4w 220K ohm CF Res 1 4w 221 ohm 1 Res 1 4w 22K ohm CF Res 1 4w 270K ohm CF Silverstein Facial N erve M onitor Stimulator Service M anual version 2 1 Stock No 3910 POPP PRP E Ho RP RBNNG NN RB HQ o o oo o o N N mn Fi kA WN k N DI k k DP Pp Page 38 Silverstein S8 Materials List con t Part Component Part Component 17058 Res 1 4w 27K ohm CF 2005
5. 1uF Disc o L GNDA 8 4V S GNDA R16 10K Ohm 250W Monitor Title R15 Silverstein Facial Nerve Monitor Stimulator S8 1K 250W COMPARITOR Size Number Rev LF353N c 3910 001 06 1 5 0 Stin Dote 11 18 2002 Drawn by TW Amp Av 10 Filename MainCB sch Sheet 1 of 4 A B Cc D E F Page 34 2 1 version Silverstein Facial N erve M onitor Stimulator Service M anual Page 35 2 1 y version A B D E F 8 4V pay 8 4v z 3 3 z y mes AS D gt E SES KSI c13 TP8 Comparator Av 1 5 Y eo gt h E ba a 1uF Disc ka N COMPARITOR KHEN LM339 N c3 R19 N de GNDA gt a S TPS wa t 4 SO 6 TA Usa 1uF 100V 10K Ohm 250W l 8 ph LM741CN 5V Mite mes One Shot pm i RSE c14 1uF Disc 5 N T IF x 5 1uF Disc D F 8 4V 1 GNDA 2 N ns xl 8 4v ONDA ESS NTE GNDA pa 0 5 x e w Sensitivity Switch R22 C4 i T ki 1 270K 250W 0 1uF 100V erm Term erm Term Term Term erm Term A B A B A B A B bk GNDA Position 1 Position 2 Position 3 Position 4 35 mV 50 mV 65 mV 100 mV Se Ze N Z esi SE poe E tas da Bdg 38 Loupe 8 4V 8 4V 3 UB 5 Footswitch Jack Driver De gel c Gen Han x IRF511 7 E U4 c S Horn Light Switch 14 LM339 Ye ki o ape Sc Sonalert ES N GNDA Remote l SES Light Ala
6. 20031 IC IRF511 Pwr Mosfet 20032 IC LF353 Dual Bifet OpAmp 20033 IC LM317T pos V reg 20034 IC LM336Z 2 5V 20036 IC LM339N Quad Comp 20037 IC LM3914 LED Driver 20048 IC Socket 14 pin 20049 IC Socket 16 pin N N H NN HN k k A Ui UP RP HK N HR RP PNB k FA WNP PN P k kA BN HUN KH KR k Hp BEE Silverstein Facial N erve M onitor Stimulator Service M anual version 2 1 Page 39 SUGGESTED READING T he following references will provide excellent reading Pay particular attention to the articles writ ten by H erbert Silverstein MD and view the video provided with the instrument e Campbell E D R A Simple Prognostic Test in Facial Palsy of Laryngology 77 462 466 June 1963 e Campbell E D R Hickey R P Nixon K H and Richardson A T Value of N erve Excitability Measurements in Prognosis of Facial Palsy Brit M ed J 2 7 10 July 7 1962 e Chase S G Hughes GB and Dudley A W N europathic Changes Following Direct C urrent Stimulation of the Rat Sciatic N erve O tolaryng H ead N eck Surg 92 615 617 Dec 1984 e Gray Jack A Nerve Stimulators and Burns Anesthesiology 42 2 231 232 Feb 1975 e Hilger Jerome A Facial N erve Stimulator trans A mer Acad O pthal amp O tolaryng 64 74 76 Jan Feb 1964 e Hughes GB Bottomy M B Dickens J R E Jackson C G Sismantis A and Glasscock III M E A Comparative Study of N europathologic C hanges Fo
7. 4 2 STIMULATOR INITIAL POWER UP STIMULATOR BATTERY METER SET AND STIMULATOR VOLTAGE REGULATOR CALIBRATION E quipment 1 Digital VOM 2 Power supply Setup 1 Set the power supply to 0 volts and turn supply off 2 UnplugtheAA battery pack Connect power supply to the AA battery pack connector observ ing polarity 3 Turn the power supply on 4 Slowly raise the power supply voltage to 4 75 volts while observing the current draw T he current draw should be approximately 20 milliamps 5 If the unit is drawing proper current check the red battery fail indicator The indicator should just be coming on at 4 75 volts 6 Adjust component R72 for battery fail at 4 75 volts if necessary 7 With the power supply at 4 75 volts adjust the stimulator voltage regulator to 3 8 volts M ovethe positive volt meter leads to the positive pole of capacitor C 16 M ove the negative leads to T P7 A djust R45 until 3 8 volts is displayed on the volt meter 4 3 STIMULATOR PULSE WIDTH FREQUENCY AMPLITUDE AND MOTOR POT OPERATION Current intensity refers to the stimulator pulse amplitude in milliamperes Stimulator pulse amplitude is measured with a 1K resistor across the output of the instrument T he voltage drop across the IK is displayed on the scope In accordance with Ohm s law the scope therefore measures pulse amplitude directly in milliamps 1 volt on scope 1 milliamp The GND jack corresponds to the PAD jack and the ACTIVE jac
8. B88 85 BB Sz 8988984839884 g x o ER KSE o 3 a Zi y gt EEN sgp 8 3 LCD Display do ddddld o 7 LM339 8 4V 5V e 7 Fail paki op U4 B 3 ae 8 4V AR 8 4v 5 8 3 S E 3 8 JB 8 D wen ne N 4 o 3 D pes NI UTa 0 3 N S E gt E TST N Monitor GND oe z XN E O COM So Monitor GND EN N E o E E x x 5 S sawl 2 INLO 3 5 High Set o d LI INHI Term 2 of rear pot R66 a S o L2 RFL Monitor GND g z 8 4V RFH H o_ Term 3 of rear pot R66 e 5 ROH Term 3 of rear pot R66 Se 3 3 3 p GNDA 03 6 S 8 S 8 Monitor RG d D2 Na E SS he S Title D o Ka 5 Seis E 5 Silverstein Facial Nerve Monitor Stimulator S8 mal Modutec Bay S Ki Size Number Rev ba e 3910 001 06 1 5 0 8 4V Date 11 18 2002 Drawn by TW Filename MainCB sch Sheet 3 of 4 A B D E F Page 36 2 1 version Silverstein Facial N erve M onitor Stimulator Service M anual A B C D E F Stimulator Battery Indicator ug 1 o 1 27V In out LM339 R74 not used 4 LM317T 3 H l U10 A a sl U10 B 620 Ohm 250W 3 2 mo gt Ba f BoE gt A Fail ai rt M339 5 Ss cy o x 3 Dk 3 el LM339 RIS a zl u10 C 620 Ohm 250W
9. N D Good Stimulator Output 5 8 0 10mA Ge 1K load SE X E Neon S lt w 3 E D Excess gt EE c y kg 5 T Resist Pulses 8 x Ti N H Second N P gei 2N3638 ua L S S 3 3 Bo 42N ned nga BS aL 2 es Zs gt ESN 2 2K 250W a8 3 BG ES Pa 2 N N 3 Q9 o gt Gain Ni a A D 3 8 aff NG E 4 SE gs 353 o Ek EK ess NTE 128 AA z Q14 q o x x o 8 A S pth E tx 1N4005 AD 5 10V 0 5Wott NTE 194 7 SI e v E 1N459A 1N5248 Q134 3 L o7 S 3 o 7 5 la b s ug E RW RW WHT E Xx A NS Sr Bs gs I8 E Neon Rj ng 94 8 E NTE 128 SE RSE BAS 3 PI lt Z Pulse ei 3 ver a e Jag ox E R66 10K J2 0122 Pulse Sg S TSE 1 turn HE 6V Width 3 aps x Front sec NTE 194 Y gt s1 B G 3 3 3 3 e 1 ono wg E gs9 39 gs gle 3 o ess ess ESN TO Is Baw pa x x x 8 N wl ng f S S KE 5 e 8G BS 05 DAG esa ofi 0 lt bi Q10 oJ eS E BARS NS EST 5 Jj Z3 x Nas ba TR EBias NTE 128 Y S ei 0 To RFH and ROH of LCD lu NTE 128 15 3 S NG S ng d x R66 10K 4 2 p Q2 Sa 1 turn ee To INHI of LCD J Rear sec PNTE 128 V Reg 1 R43 N 3 8V 4 ges ES E 10K Ohm 250W TP7 GNDA A 5 Stimulator x a Q4 N Title A We t d Silverstein Facial Nerve Monitor Stimulator S8 NTE 158 eRe Size Number Rev c 3910 001 05 1 5 0 Date 11 18 2002 Drawn by TW Filename MainCB sch Sheet 4 of 4 A B Cc D E F Page 37 2 1 version Silverstein Facial N erve M onitor Stimulator Service M an
10. TP1 attach Ce E the negative leads of the volt er strain gauge meter to TP6 monitor we ground 3 Turn the unit on The voltage reading should be between 5 volts and 4 volts Do NOT A djust the offset if the read ing is within these limits be cause each sensor hasa slightly white outer strain gauge different offset T he proper set ting allows using many differ ent sensors on each unit If it is not within tolerance the sensor is defective or the unit connector needs calibration cable ground shield red common Figure 9 4 WR Medical Electronics suggests sending the complete unit to them if calibration is necessary If you attempt to adjust the input use two 350 ohm resistors connected in series that are within 2 of each other in place of the sensor s strain gages refer to Figure 8 The common point is where the two resistors connect together This point represents the center connection on the sensor plug where the strain gages meet Attach the remaining end of each resistor to there respective location See the schematic for details before attempting this procedure A djust R2 until 2 volts is obtained A fter calibration repeat step 1 2 and 3 of section 4 5 part 2 If the offset is still not within specifications the sensor is defective and must be repaired or replaced 5 After completing part 2 tap lightly on the sensor to test for alarm outpu
11. not penetrate the fabric and will not assure good electri cal contact The purpose of the fabric layer is to retain the THERASOL electrode cream and maintain good conductivity during long surgical procedures The T HERAT RODE pad isdisposable and if it is reused the solids from previous applications of THERA SOL cream will retard penetration of the cream and Cause excessive resistance When the patient is being prepared for surgery apply the THERAT RODE electrode pad saturated with THERASOL cream in an appropriate area outside the sterile field underneath the drapes and secure it with adhesive tape A ttach one end of the Pad ground cable to the snap connector on the pad allowing the other end to extend from beneath the drapes for later connection to the unit PULSE LIGHT W hen instrument is on the clear PULSE light flashes with each pulse of the stimulating current indicating that the instrument ison and that the stimulator section is functioning Between stimulat ing or monitoring activity turn the instrument off to conserve battery power HORN LIGHT SWITCH TheHORN LIGHT switch is used to select aural or visual signal at the option of the surgeon In cases where other patient alarms have a similar aural signal or where the operating environment may be too noisy to hear the audible tone the visual signal may be selected An extra loud audio signal has been provided for procedures where other surgical equipment may generate subst
12. the current inten sity should increase But above 5 0 milliampsthe cur rent should not increase 1k 1 1 4w 3 The incomplete stimulation light should come on between 4 5 and 5 2 milliamps If any problems are found in section 3 return complete unit to WR M edical Electronics for repair If you are quali fied and choose to perform Calibration procedures your self please follow section 4 If the unit isopened section 3 must be repeated after the enclosure is closed T his helps Figure 8 assure safe and reliable operation IS Silverstein Facial Nerve M onitor Stimulator Service M anual version 2 1 Page 27 4 0 CALIBRATION PROCEDURES WR M edical Electronics recommends contacting there Technical Service Department with the unit serial number before attempting Calibration procedures The Dept can check on any recommended modifications for your unit A fter completing section 4 refer to section 3 for a final check out with the case closed In section 4 the case must be opened to recalibrate settings 4 1 POWER UP The monitor section of the Silverstein runs on two nickel cadmium battery packs located in a battery case black inside of the main enclosure To access the nickel cadmium battery packs the Silverstein S8 enclosure and the battery case must be opened E quipment 1 Two Digital VOM s fused Setup 1 Separate the nickel cadmium battery connectors and put an ammeter in series with the positive red battery
13. the sensor T he gauge differentially detects changes in pressure of the facial muscle e Voltage Reference and Bridge A 5 volt reference and bridge is used to put current through the differential strain gauges Changes in pressure yield a small change in voltage e Hi Gain Differential A mplifier A high gain differential amplifier Gain X 500 is used to amplify the differential voltage e Precision Rectifier Detects zero crossing points and converts signals to pulsed DC signals e Bandpass Filter 10 200 Hz twin T bandpass filter Removes DC component and filters out electrical noise e Adjustable Voltage Reference T he user may select 4 sensitivity levels which are represented by 4 discrete voltage references which are used by the signal comparator e Comparator Detects peaks of input pressure signal and compares them with input reference signals If a peak ishigher than the reference signal the output istransmitted to the Pulse Stretcher e Pulse Stretcher C onverts detected peak into 1 second 5 volt pulse that then triggers the audio visual alarm Driver and A larm Drives LED indicator and Sonalert audio alarm 1 3A STIMULATOR BLOCK DIAGRAM Voltage Pulse Regulator Generator TI 9 N Adjustable Stimulator Output Volts Driver Transformer Constant Current ROON In eg P Generator 1 3B STIMULATOR BLOCK DIAGRAM DESCRIPTION
14. 4 IC Socket 18 pin 1 17059 Res 1 4w 3 3K ohm CF 20056 IC Socket 8 pin 13 17061 Res 1 4w 3 9M ohm CF 20065 Transis 2N 3638 2 17063 Res 1 4w 330K ohm CF 20068 Transis NTE 194 4 17064 Res 1 4w 33K ohm CF 20069 Transis 2N6027 1 17066 Res 1 4w 4 7K ohm CF 20070 Transis 2N 697 4 17067 Res 1 4w 43K ohm CF 20074 Transis GE 53 Phil ECG 158 1 17068 Res 1 4w 470 ohm CF 20092 Diode 1N4005 2 17070 Res 1 4w 47K ohm CF 21010 SW relay 2 Form C 2 17071 Res 1 4w 5 1K ohm CF 21011 SW rotary 3P4T 1 17074 Res 1 4w 6 8 ohm CF 21014 SW toggle 3PDT 1 17075 Res 1 4w 620 ohm CF 21015 SW toggle SPDT d 17076 Res 1 4w 8 2K ohm CF 21016 SW toggle SPDT on off on 1 17082 Res 1Ow 75 ohm 22004 Wire Set 58 1 17085 Res Pot 10K 10 turn 2 Section 23014 Manual pgs SS opr 3009 1 17098 Res Trimpot 25 turn 100K top adj 23015 Manual pgs SS serv 3010 1 17103 Res Trimpot Piher 100k ohm 23016 Manual pgs H3 opr 3025 1 17104 Res Trimpat Piher 10k ohm 23017 Manual pgs H3 serv 3024 1 17107 Res Trimpot Piher 1k ohm 23018 Manual pgs SACS kit opr 3029 1 17108 Res Trimpot Piher 200 ohm 23019 Manual pgs Br Il serv 3170 1 17109 Res Trimpot Piher 20K ohm 23020 Manual pos Br Il scientific 3169 1 17110 Res Trimpot Piher 500 ohm 17111 Res Trimpot Piher 5K ohm 17131 Res pot 25turn 20K top adj 20005 Diode 1N2069A 20007 Diode 1N459A 20013 Diode 1N5240 20014 Diode 1N5267 20015 Diode 1N914 20017 IC 1458 Dual OpAmp 20019 IC 741 0pAmp 20020 IC 7805 Vreg
15. Check the Stimulator Bias Current and Gain Check the bias current intensity display at 0 00 for 50 microamps or 50 millivolts displayed on the scope Check the current gain by adjusting the scope to 2 volts division and changing the unit s current intensity to 10 milliamps By ohms law 10 volts dropped across a 1K resistance equals 10 milliamps E 1 R 2 To Check the Stimulator Pulse Frequency pw 2 ms frq 200 ms not to scale frq Jout 50UA to 10mA Vdrop SOUN to 10V not to scale e Setthe scope sensitivity at 2 volts division sweep at 20 milliseconds div and align the triggered pulse precisely on the grid line on the far left Figures 6 top and 7 side of the screen Check the frequency for 200 milliseconds 3 To Check the Stimulator Pulse W idth e Reset the sweep to 0 1 milliseconds division and check for a pulse width of 0 2 milliseconds If unit is out of calibration return to WR Medical Electronics for calibration 3 6E STIMULATOR OUTPUT LINEARITY AND EXCESS RESISTANCE LIGHT TEST Equipment Same as in step 3 6d oa E Setup 1 Scope sweep at 1 milliseconds division sensitivity to 2 volts division DC coupled slope at negative 2 Set current intensity display on the Silverstein 58 to 10 00 milliamps PART A Procedure 1 Disconnect the stimulator output load IK ohm The excess resistance light should flash 2 Reattach the IK load 3 Adjust the current intensi
16. H ead N eck Surg 113 1291 1293 Dec 1987 Silverstein Facial N erve M onitor Stimulator Service M anual version 2 1 Page 40
17. OARD pista EL PAUL ARREST aika COMPONENT LAY OUT deg Sve Silverstein Facial N erve M onitor Stimulator Service M anual version 2 1 Page 33 A B C D E F 8 4V 5V TAPI LM7885CT T Ly vo H 8 4v d x SC uy pe DAG Female Recept SS 74 2 6 Hypertronics 3 3 _LGNDA DOZEE7Q6FSTAH g re C7 W aa D aa t 1 CNDA MG ES 1uF Disc Male Plug 3 5 TPI Hypertronic 7 4 25 poozpro6ustH 8 AL LF3SIN Loun 9 7 AE xE Differential Amp j g HE L GNDA Lon U11 Filter Av 270 R4 C6 IR 290W 1uF Disc x GNDA 3 8 4V D S esa ost 2SN te R5 TE 8 5 270K 250W Inner Strain Outer Strain E C15 Gauge 350 Ohm Gauge 350 Ohm 220pF 3kV GNDA Bandpass Filter Av 1 R9 c1 R7 10K Ohm 250W Full Wave Precision At 10K Ohm 250W IT m4 1N914 Ris Kita 15K Ohm 250W E la 5K Ohm 250 8 4V c9 NI Li R1 1uF Disc 9 ch 1 R6 10K Ohm 250W TP2 t L N mng U2A L CNDA 1N914 m 0 1uF Disc 10K Ohm 250W 1 HG T Peb R12 c2 A Mc1458P D2 5 1K 250W 5 2 He ng 3 1 GNDA ag R11 54 MC1458P 8 2K 250W TuF 35V 4 GNDA L i CEA LF353N PAYA bise 2 7K 250W 3 A L CNDA ONDA 2 R GNDA cle 8 4V
18. RVICE amp REPAIR Because of the specialized circuitry of this instrument the need for special test instruments and our familiarity and experience with thisinstrument we recommend that the instrument be returned to the factory for any necessary checking or servicing except routine battery replacement Seethe W arranty Service and Loaner Program section of thismanual for return instructions T his unit should be repaired only by qualified biomedical electronic tech nicians e GROUND ELECTRODE PLACEMENT Do not place any stimulator ground electrodes on the chest or in close proximity to a pacemaker Interference with the pacemaker could occur If there is any uncertainty as to stimulator pacemaker interference do not use the stimulator on pacemaker patients E Silverstein Facial N erve M onitor Stimulator Service M anual version 2 1 Page 6 INTRODUCTION TheSILVERSTEIN FACIAL NERVE STIMULATOR MONITOR Model 58 isa greatly enhanced version of the JAKO FACIAL NERVE MONITOR which hasbeen in use since 1974 T he methods of stimulation and monitoring have remained unchanged from the JA KO and the intended use remains the same but the M odel 58 is much more sensitive and has additional controls to make operation of the instrument easier The Silverstein Facial N erve Stimulator M onitor M odel 58 uses adjustable precisely controlled low energy pulses to stimulate the facial nerve A highly sensitive muscle movement sensor detects the re
19. Sensitivity Switch and Alarm Attacke AAA 10 System COMPONENG eeng 11 Testing for Stimulus O utput Stimulus Verification 11 Battery Condition Indicator and Battery Charging maana 12 Installing the Cheek Muscle Movement Sensor u s 12 Checking the Sensor eg EE 13 Care of the E 13 The Remote PrODE senses loia titi 13 AA Un ie saceid ee nee 13 Pad Ground Calar 13 Skin Preparation asaan 14 PPV Eet 14 Kaman E 14 Use Or the Remote Li Eu Eege Eed 14 Ile 15 General Theory Of Nerve SUMULILION seras rea 15 General Procedure for Use of the Model SB ccecsssseessssesesssreesssesssssrerersnaeeess 16 Finding a Nerve Underlying O ther Tissue u s 16 Indicating Proximity Of a Nerve u nono nnnnnnnccnconononnnnnnnrnnnnnnnos 16 Nerve En et E 17 Nerve tin PPP RERAN 17 MAINTENANCE 1 0 MAINTENANCE INTRODUCTION ula 18 1 1a O utp tinp t KEE cxciccsscsadesnnsectecsesssxesacenseionsextecsenestutaasatmnenietecnesersehau ens 18 1 1b Technical Specification saciar 19 1 23 Monitor Block Daan ma NAAN KATAGA AGA GASA NAA 19 1 2b Monitor Block Diagram Description Kaanak 20 1 3a Stimulator Block Diagram nit 20 1 3b Stimulator Block Diagram Description E 20 E l y yll TZTqZ8T86666qq 28z8sz8riIi 5352 Silverstein Facial N erve M onitor Stimulator Service M anual version 2 1 Page 3 2 0 MAINTENANCE SCHEDULE nr nnrrrrranass 21 2 1 The Following Actions M ust Be Taken After Each Uee aaa aaaaaaaa 21 2 2 The Following Actions Must Be Ta
20. Superior Systems for Every Need Silverstein Facial N erve M onitor Stimulator Model 58 Service M anual Verson 2 1 aY P4 MEDICAL ELECTRONICS CO COPYRIGHT INFORMATION This manual copyright 1992 1997 2003 by WR Medical Electronics Co All rights reserved No part of this manual may be reproduced in any form by any means graphic electronic or mechanical including photocopying recording taping or any information storage and retrieval system without the written permission of WR Medical Electronics Co All WR Medical Electronics Co products including Silverstein Silverstein A dapter for C ontinuous Stimulation SACS Brackmann Brack mann Il and Theratrode are trademarks or registered trademarks of W R M edical Electronics Co Silverstein Facial N erve M onitor Stimulator M odel 58 Service M anual version 2 1 item no 3010 revised 05 13 03 P N 920 W 0 23016 WR M edical Electronics Co 123 North Second Street Stillwater MN 55082 USA 651 430 1200 FA X 651 439 9733 Toll free 800 635 1312 Toll free FA X 800 990 9733 Silverstein Facial N erve M onitor Stimulator Service M anual version 2 1 Page 2 CONTENTS GENERAL Electrocautery ET ne EE 5 EE nt Caen EE 5 ageet Te 7 Features of the Moderno oia 7 Warranty Service and Loaner Program u s 8 Sterilizati n Eer Un 8 Current Ee E RE 8 9 Paralyzing DING aaa daria 9 Procedures Tor U se with Electrocautery UN maam 9 Sensitivity the
21. antial sound levels The sound level may be easily reduced to a comfortable level by adjusting the sound attenuator on the face of the horn USE OF THE REMOTE LIGHT With the HORN LIGHT switch in the LIGHT position the REMOTE INDICATOR LIGHT if plugged in will activate at the same time as the red panel light TheREMOTEINDICATOR LIGHT may be placed in a position convenient to the surgeon s or other staffs field of vision This is useful where the monitor which is placed outside the surgical field cannot be readily viewed Silverstein Facial Nerve M onitor Stimulator Service M anual version 2 1 Page 14 TILT STAND Thetilt stand can be rotated to the rear of the instrument to allow placement on a stack of monitoring equipment To rotate pull both stand hubs out simultaneously and rotate underneath the instrument GENERAL THEORY OF NERVE STIMULATION Electrical stimulation of a nerve or nerve branch evokes contractions of associated muscles affording a visual confirmation of the response to the stimulation A certain minimum level of current intensity through the nerve tissue is required to reach the stimulation threshold and produce minimal muscle contractions A sthe current isincreased above thislevel the contractions become progressively stronger until the point at which the entire muscle is responding ZEN sd Wee fully Y Probe Probe W hen a stimulating current is applied directly to an exposed Nerve nerve fig
22. ator Service M anual version 2 1 Page 23 5 Tap on the top sensor blade lightly the top blade has a thumb screw the audio alarm should sound 6 Repeat steps 1 5 for sensitivity settings 2 3 and 4 7 While taping on the sensor lightly to evoke the audio alarm step on the foot switch N o audible response should be evoked 8 If audible alarm does not cease when you step on the foot switch while taping on the sensor check the foot switch with an ohm meter for continuity when the foot switch is at rest Also check for infinite resistance when the switch is stepped on If fault cannot be found return complete unit to WR M edical Electronics for repair 3 6 STIMULATOR CALIBRATION CHECK Procedures in section 3 6a through 3 6f are to be done without opening the unit enclosure 3 6A STIMULATOR AA BATTERY PACK CURRENT DRAW Thisstep checks the circuit board and wiring to be sure that excessive current isnot being drawn from the stimulator AA battery pack E quipment N eeded 1 Power supply 2 VOM meter Setup 1 Open the small gray door on the rear of the unit 2 Disconnect the AA battery pack 3 Set the power supply to zero 0 volts 4 Turn the power supply off Procedure 1 With the Silverstein 58 power switch in the off position observe polarity and connect wires from the power supply to the stimulator battery connector with an in line A mmeter 2 Turn the unit on and slowly bring the power supply voltage up
23. atteries M onitor Battery Life Stimulator Battery Life Case Size Current C haracteristics Sterilization G uidelines 1 1B TECHNICAL SPECIFICATIONS 0 to 10 mA residual 05 mA at 0 indicated 02 M sec 200 M sec 5 Hz Linear down to 15 mA residual current of 05 mA at 0 indicated Two 8 4 volt 2 2 AH nickel cadmium packs Four 1 5 volt AA alkaline batteries 11 hours continuous use when fully charged Charge after each use and once a month Replace nickel cadmium pack once a year 300 hours replace when stimulator battery fail indicator light illumi nates 8x5x9 inches 21 x 13 x 23 cm Constant pulsed current stimulation A ccurate delivery from 0 10K ohm load at 1 mA typical Gasonly Remote Probe M uscle Sensor R emote Indicator Light Steam G as Pad Ground Cable Probe Tips 12A MONITOR BLOCK DIAGRAM Sensor High Gain gt Kach ai gt Differential e Amplifier Comparator Bandpass ea Precision Filter Rectifier Adjustable a Voltage Pulse o Driver gp Audio Stretcher Out Reference NJ Silverstein Facial N erve M onitor Stimulator Service M anual version 2 1 Page 19 1 2B MONITOR BLOCK DIAGRAM DESCRIPTION e Dual Strain Gauge Sensor Clip type muscle movement sensor is clamped to the facial muscle Consists of two strain gauges located on the upper blade of
24. binding posts accept banana plugs spade lugs alligator clips or bare wire Either plug can be connected to either AU X jack Shorting the probe tips or AUX jacks together will not harm the instrument N o reference electrode is required when a bipolar stimulating probe is used Surgical instruments having a black non reflective coating are not suitable for applying the stimulating current because of the high electrical resistance of the coating PAD GROUND CABLE W hen a unipolar probe is used either the Remote Probe or a customized probe a ground Pad must be used to complete the electrical path through the patient Silverstein Facial N erve M onitor Stimulator Service M anual version 2 1 Page 13 SKIN PREPARATION An indifferent electrode pad also called a ground pad applied to the skin outside the sterile field completes the stimulator circuit through the patient Use WR Medical THERAT RODE or new self adhesive THERATRODE II for best results If using the THERAT RODE pad and to minimize the electrical resistance between the electrode and skin the fabric layer of the pad must be thoroughly saturated with TH ERA SOL electroconductive cream so that the cream reaches the underlying layer of foil A small amount of the electrode cream should also be massaged into the skin to break down the natural skin oils and reduce the electrical resistance THERA SOL cream readily soaks through the fabric layer but electroconductivity gels may
25. ch tissues or fluids in the surgical field Electrocautery voltages can damage the stimulator and monitor circuits and cause a burn at the location of the indifferent electrode pad if the stimulator probes are allowed to touch the patient s tissues or fluids while electrocautery is energized e Alarm artifactscan also occur when electrocautery units are energized Interference from electro surgery is common with many monitoring instruments The high energy of electrocautery units simply cannot be kept out of sensitive monitoring circuitry The monitor has been deliberately Silverstein Facial N erve M onitor Stimulator Service M anual version 2 1 Page 9 designed to be quite sensitive in order to respond to very small muscle response T his sensitivity can cause artifacts that are not a result of nerve stimulation Patient movement and accidental contact with cables can also cause a monitor response O peration of electrosurgery cautery equip ment may also cause a false response depending on the equipment cable and electrode arrange ment and other unknown factors SENSITIVITY THE SENSITIVITY SWITCH AND ALARM ARTIFACTS In position 1 the monitor is most sensitive To desensitize turn the knob to numbers 2 3 or 4 This instrument is highly sensitive and has been designed to pick up the slightest vibrations and contractions of the cheek muscle The sensitivity of the instrument is primarily determined by how the sensor isinstalle
26. ct the probe from the unit A ttach a jumper wire between the activeand GN D jack the incomplete stimulation should go out indicating a complete electrical path If malfunctioning return to WR M edical Electronics for repair 3 6D STIMULATOR PULSE WIDTH FREQ UENCY AND AMPLITUDE CHECK Current intensity in this section refers to stimulator pulse ampli tude in milliamperes Pulse amplitude is measured with a 1K re sistor across the output of the instrument T he voltage drop across Silverstein S8 the resistor is displayed on the scope In accordance with Ohm s Ken law the scope measures the amplitude directly in milliamperes 1 volt 1 mA GND ACTIVE The Active jack corresponds to the active electrode and is con 2 3 nected to the positive scope terminal The stimulator GN D jack is connected to the negative scope terminal A 1K 1 4W resistor is placed across the jacks See figure 5 for setup 1k 1 1 4w The output pulses are negative going on the scope See figures 1 6 and 7 for description of waveform Figure 5 Silverstein Facial N erve M onitor Stimulator Service M anual version 2 1 Page 25 E quipment 1 Oscilloscope 2 IK 1 4 watt resistor Setup 1 Set the scope sweep to 1 milliseconds division sen sitivity to 10 0 millivolts division DC coupled slope to negative 2 Set the current intensity display on the Silverstein S8 to 0 00 mA a e Procedure 1 To
27. d and physiological factors of the patient It isimpossible to quantify how small of a contraction could be detected but the instrument has the capability under certain conditions to pick up the expansion of tissue due to blood flow T his has been demonstrated in the lab and has been reported by surgical personnel If you detect a blood pulse turn the sensitivity down to the next level Generally you will want to use the instrument on the most sensitive setting possible A larm artifacts sometimes signify a problem and sometimes can be ignored It isimperative that you learn their causes and meanings A rtifacts will be caused by the following e Movement of the drapes operating table or tubes near the face or in the mouth e Adjustment of the stimulus output current The alarm will sound when the current is being adjusted on some or all sensitivity levels This is a normal occurrence and does not indicate a fault with the unit This occurs because the monitor is so sensitive it can detect the loss of electrons from the nickel cadmium battery pack due to current draw by the motorpot e Energizing of electrocautery Use the foot switch provided with the instrument to disable the alarm when electrocautery is energized The LIGHT position may also be used W hen locating nerves be sure that interfering equipment is off Since the cheek can only contract asa result of nerve impulses and since sensor only picks up contrac tions as a result
28. e unit with its probes sensor and cables via insured parcel post or insured U PS Be sure to pack with plenty of padding to prevent damage during shipping Loaner units are available at no charge except for shipping insurance and any loaner supplies used STERILIZATION GUIDELINES Gas sterilize only M uscle Sensor Remote Indicator Light Remote Probe Gas or Low Pressure Steam Probe Tips Indifferent Electrode pad Cable The Sensor Probes and C ables should not be immersed in liquids but may be wiped with cleansing agents T he cables should be carefully coiled to prevent tangling and kinking CURRENT CHARACTERISTICS The Model S8 is safer than most constant voltage or non pulsed DC stimulators because it delivers pulsed constant current stimulation To illustrate the amount of energy transmitted to the patient is proportional to the amplitude of current in milliamperes and the duration of the pulse C onstant voltage units can deliver excessive current because these units au tomatically deliver an unlimited amount of current subject to circuitry limitations to meet the voltage chosen by the opera tor In some cases this can damage nerve tissue Likewise non pulsed D C stimula tion may damage nerve tissue because they allow non pulsed current to be transmit ted through the nerve aslong asthe probe tip touches the nerve The Model 58 al Ov SE lows stimulation to be applied directly on Current Voltage nerve t
29. en the probe tip and the nerve The nerve underlies the point at which muscle contractions occur with the lowest current setting INDICATING PROXIMITY OF A NERVE At the beginning of the surgical procedure while the exposed tissues are still a good distance from the nerve turn the current up high enough to cause muscle contractions and sound the signal T his will verify that the instrument is functioning properly and will establish as a reference the current intensity corresponding to the initial distance from the nerve T hen turn the current down until the signal stops sounding As you dissect the overlying tissues and get closer to the nerve you will provide sufficient intensity through the nerve to evoke contractions and sound the signal As you continue the dissection turn the current to successively lower levels to sound the signal at correspondingly shorter distances from the nerve Experience with the instrument enables the surgeon to relate the current settings required to evoke contractions to the corresponding distances from the nerve It must be borne in mind that as you approach a nerve a given change in current setting corresponds to progressively smaller increments of distance W hen a current setting of about 0 2 mA actuates the signal it indicates that the nerve is quite close If the signal does not sound after further dissection of the tissue has brought you significantly closer to the nerve turn the current setting back u
30. issue without risk of over stimula tion Figure 1 known amplitude IT Q LI Loi zl A NO o 0 2 PULSE WIDTH v 2 Silverstein Facial N erve M onitor Stimulator Service M anual version 2 1 Page 8 OUTPUT PARAMETERS TheM odel 58 provides a square wave pulse which is adjustable from 05 mA residual current to 10 0 mA maximum current by means of the remote probe or a switch on the front panel Current inten sity refers to the amplitude of the individual pulses not to the average level of current Between pulses there is no current N erve response to electrical stimulation is a function of current intensity through the nerve rather than of applied voltage Consequently precise control of current intensity is essential for quantitative evaluation of nerve response In the M odel S8 the voltage is automatically adjusted utilizing a con stant current output to compensate for any differences or changes in the patient stimulator circuit resistance so that the current is constant at any given setting of the current intensity display The pulse width is 0002 sec with an off time of 1998 sec for a total period of 200 sec T he corre sponding frequency is 5 pulses per second T here is a residual current of 05 mA when the display is at The pulse width of 0002 seconds has been found to be optimal for subcutaneous intraoperative stimulation For transcutaneous stimulation a pulse width
31. k corresponds to the probe tip or active electrode T he output pulses are negative going on the scope See Figure 1 for complete description of stimulator waveform E quipment 1 Oscilloscope 2 IK 1 1 4W resistor Setup 1 Attach a 1K resistor across the output of the stimulator see figure 5 between ACTIVE and GND 2 Attach the scope input across the stimulator output see figure 5 ACTIVE to pos GND to neg 3 Scope sweep 1 milliseconds sensitivity 10 millivolts division DC coupled slope at nega tive Silverstein Facial N erve M onitor Stimulator Service M anual version 2 1 Page 29 4 Set the Silverstein 58 current intensity display to 0 00 mA Procedure 1 Turn unit on and set the stimulator bias with R62 to 50 microamps 50 millivolt on scope Change scope sensitivity to 2 volts division set the current intensity display to 10 mA and adjust the gain trimpot R59 to 10 milliamps amplitude 10 volts on scope 2 Thebiasand gain trimpotsare interactive Repeat step 1 above until both the bias 50 microamps and the gain 10 milliamps are correct 3 Set scope sensitivity to 2 volts division sweep to 20 milliseconds division and align the triggered pulse precisely on the far left grid division marker 4 Adjust the pulse frequency trimpot R 60 to 200 milliseconds 5 pulses second 5 Reset the sweep to 0 1 millisecond division and A djust R 46 for a pulse width of 0 2 milliseconds 6 The m
32. ken Every Three Month 21 2 3 The Following Actions M ust Be Taken Every eat 21 3 0 MAINTENANCE PROCEDURES ociosa 22 3 1 Sterilization GUIACINES a naaa a 22 3 2 Monitor Battery Recharge EE 22 3 9 Simulator Battery CHECK geegent Eege dE NAAN 22 23 3 5 Sensor Audio Alarm and Footswitch ss 23 3 5a Cheek Muscle Movement SeNnsor ccsscccsssscesssseesssssesssseresssseeesseseeeessns 23 3 5b Audio Alarm and Foot WIN aaa AA 23 3 0 Sumulator Cahbration COS lia bad 24 3 6a Stimulator AA Battery Pack Current Draw u a 24 3 6b LCD Current Intensity Display Drift Check cccccccnnnononoccccnnnncccnnnnnnnn ones 24 3 6c Remote Probe Pad Jack Aux Ground Jack Check ococonococccocononnncnonononnnos 25 3 6d Stimulator Pulse Width Frequency and Amplitude Check sssr 25 3 6e Stimulator O utput Linearity and Excess Resistance Light Test 26 4 0 CALIBRATION PROCEDURES a 28 MAL POWER UD EE 28 4 1a Monitor Battery Meter Calibration maa GI AA 28 4 2 Stimulator Initial Power Up Stimulator Battery M eter Set and Stimulator Voltage Regulator Calibration 1 111 1 29 4 3 Stimulator Pulse Width Frequency Amplitude and Motor Pot O peration 29 AA MONILOP SENSON E 30 4 5 Cheek M uscle Movement Sensor and Instrument Input Calibration 30 4 6 Closing the Enclosure After Completing Preliminary Calibration Procedures 31 APPENDICES suis 32 Board Lavouta
33. leads 2 Put an ammeter in series with the negative black battery leads 3 Attach the remaining two battery connections to there matched connections with two jumpers Procedure 1 Turn the ammeters on 2 Turn unit on momentarily T he positive side of the battery supply should draw approximately 50 milliamps and the negative side of the battery supply should draw approximately 100 milliamps 4 1A MONITOR BATTERY METER CALIBRATION E quipment 1 TwoVOM 2 Power Supply Setup 1 Ed the unit off and unplug all peripheral equipment from the unit including the wall mount charger 2 Removethefour enclosure screws and open the unit Be careful not to put excessive strain on any wires Separate the two M olex battery connectors 4 Adjust the power supply to 16 8 volts then turn the supply off Attach the positive from the power supply to the red wire on the circuit board side of the M olex connectors 6 Attach the negative from the power supply to the black wire on the circuit board side of the M olex connectors Procedure 1 Adjust component R35 until both the green and yellow battery LED indicators on the front panel flicker Silverstein Facial N erve M onitor Stimulator Service M anual version 2 1 Page 28 2 Turn the supply down to 16 2 volts T he red battery fail indicator should come on at this point If the fail indicator does not illuminate adjust component R70 until it just comes on at 16 2 volts
34. llowing Pulsed and Direct Current Stimulation of the M ouse Sciatic N erve Amer J Oto 1 5 378 384 N ov 1980 e Lippmann M aurice Fields William A Burns of the Skin C aused by a Pheral N erve Stimulator Anesthesiology 40 1 82 84 Jan 1974 e Love Jr J T and M archbanks J R Injury to the Facial Nerve A ssociated with the Use of a Disposable N erve Stimulator O RL 86 61 64 Jan Feb 1978 e Prass R L Kinney S E Hardy Jr R W Hahn J F and Luders H Acoustic Loudspeaker Facial EMG Monitoring Il Use of Evoked EMG A ctivity During A coustic N eroma Resection Otolaryngol H ead N eck Surg 97 6 541 551 Dec 1987 e Silverstein H Microsurgical Instruments and N erve Stimulator Monitor for Retrolabyrinthine Vestibular N eurectomy O talaryngol H ead N eck Surg 94 3 409 411 1986 e Silverstein H Smouha E JonesR O Routine Intraoperative Facial N erve M onitoring During Otologic Surgery Amer J Otol 9 4 269 275 July 1988 e Silverstein H Smouha E and Jones R O Routine Identification of the Facial N erve U sing Electrical Stimulation During Otological and N eurotological Surgery Laryngoscope 98 1 4 July 1988 e Silverstein Herbert Surgery of the Facial N erve J of Otolaryngol 10 6 449 458 1981 e Zini Carlo Gandolfi A ngelo Facial N erve and Vocal C ord M onitoring During O toneurosurgical Operations Otolaryngol
35. nd SONA geet 33 Parts Bi AA AA AA AA 38 ll een Le E 40 Silverstein Facial N erve M onitor Stimulator Service M anual version 2 1 Page 4 READ ME FIRST M emorize T hese Warnings Before U sing T his Instrument in the O R ELECTROCAUTERY WARNING To avoid patient burns and damage to the unit observe the electrocautery precautions in the Operator s manual K eep the ground electrode pads of the two units separated by at least 6 inches and keep the area between them free of electroconductive cream Do not allow the cables of the electrocautery unit to be routed near the stimulator monitor cables or sensor Keep both sets of cables at least 6 inches apart N ever allow the electrocautery and stimulator probes to contact each other or simultaneously touch tissues or fluids in the surgical field OTHER WARNINGS AND CAUTIONS SENSOR INSTALLATION Read and understand the section in this manual that describes proper installation of the cheek muscle sensor ALARM ARTIFACTS Read and understand the section in this manual that covers alarm artifacts their causes and meaning M onitor alarm may sound while output is being adjusted SENSOR CARE amp STERILIZATION Read and understand the section in this manual that covers care of the sensor and sterilization guidelines Do not steam sterilize the muscle sensor or the remote probe Do not immerse in fluids PARALYZING DRUGS Read and understand the section in this manual on the effect of
36. nt s cheek lightly and get a response CARE OF THE SENSOR The sensor is quite delicate and should be treated with care Pulling on wires repeated bending especially sharp bends can cause broken wires or intermittent false signals T he sensor does not need to be sterilized because the patient s mouth is not a sterile field The sensor may be cleaned by wiping with cold cleaning or sterilizing solutions and may be gas autoclaved It must not be immersed in cleaning solutions and must not be steam autoclaved because such procedures will draw moisture into the sensor and the cable causing corrosion and malfunctioning of the instrument THE REMOTE PROBE The Remote Probe accepts seven interchangeable tips to meet different needs T he long tips are insu lated so they will not short out against the edge of the incision The tip is secured in the probe chuck by tightening the chuck nut The remote probe has two buttons for controlling current output The front button is up the rear button is down To connect the remote probe to the front panel align connectors insert plug and rotate locking collar on plug Never simultaneously press both up and down buttons AUX STIMULATOR JACKS A ny standard bipolar forceps type probe can be used Current can be controlled using either the remote probe or the switch on the front panel If the remote probe is used to control current use caution as the tip is active whenever it is plugged in The AUX
37. obe mounted output control Allows the surgeon to quickly adjust current as sur gery proceeds eliminating the need for additional personnel 4 Easy to read lighted digital current display Easily read from a distance in a darkened operating room 5 Stimulus verification indicator M onitors the integrity of all cable connections and verifies that proper current is being delivered Shatterproof case W ithstands accidental abuse High output audible alarm for high ambient sound level with adjustable sound attenuator U ser selectable audible or visual signal oo 4 A uxiliary panel jacks for bipolar forceps type stimulator probes Silverstein Facial N erve M onitor Stimulator Service M anual version 2 1 Page 7 WARRANTY SERVICE AND LOANER PROGRAM The Model 58 main unit is warranted to be free of defects in material and workmanship for a period of one year from purchase The peripheral equipment is warranted for 90 days from date of purchase Warranty is void if the unit has been damaged by electrocautery Service and technical questions are welcome Because of the specialized circuitry of this instrument the need for special test instruments and our familiarity and experience with this instrument we recommend that the instrument be returned to the factory for any necessary checking or servicing except routine battery replacement T his unit should be repaired only by qualified electronic techni cians To return a unit ship th
38. of 0006 secondsisrequired due to the skin barrier Stimulators with a 0006 second pulse width are available from W R M edical Electronics Stimu lators with a 0006 second pulse width may be used subcutaneously without ill effect but a 0002 second wave will not be effective transcutaneously PARALYZING DRUGS A fairly high concentration of X ylocaine injected in close proximity to the facial nerve can reduce its responsiveness to the stimulating current and or paralyze the nerve so that the muscle does not re spond to electrical stimulation H owever it has been found that solutions containing one per cent or less of X ylocaine injected in normal quantity and not unduly close to the nerve do not appear to affect the function of the M odel 58 Succinylcholine can also cause muscle paralysis and prevent the facial muscles from contracting dur ing stimulation PROCEDURES FOR USE WITH ELECTROCAUTERY UNITS Procedures should be established to insure that the following precautions are taken e Keep the ground electrode pads of the electrocautery unit and stimulator unit separated by at least 6 inches and keep the area between them free of electroconductive cream Donotallow thecablesof the electrocautery unit to be routed near the stimulator monitor cables or sensor Keep both sets of cables at least 6 inches apart e Never allow the electrocautery probes stimulator probes or monitor sensors to contact each other or simultaneously tou
39. of impulses natural or artificial stimulation most artifacts can be ignored with this exception In some cases the exposed nerve will spontaneously fire impulses when it is directly manipulated with a surgical instrument bumped with a tool or irrigated with cold fluids If the spontaneous impulses are large enough they will cause a contraction large enough to be detected by the sensor The sensitivity levels of each sensitivity switch position 1 2 3 and 4 can be checked and modified as outlined in the service manual Settings should be set according to the latest standards issued by WR Medical Electronics BEE Silverstein Facial N erve M onitor Stimulator Service M anual version 2 1 Page 10 SYSTEM COMPONENTS The Silverstein Facial N erve Stimulator M onitor Model 58 Components Remote Control Probe Pad ground Cable Remote Indicator Light Cheek muscle Movement Sensor Foot Switch Set of 3 Snaps 7 Probe Tips Short Pointed Short Blunt Long Pointed Std Long Pointed M edium Long Pointed Fine Long Blunt Long Flush Tip Therasol Electrode C ream 4 oz Bottle T heratrode Disposable Electrode Pads Pkg of 10 O perator s M anual Service M anual Reference Papers Video Tape Electrocautery Warning TESTING FOR STIMULUS OUTPUT STIMULUS VERIFICATION The unit may be tested for output by touching the active electrode to the ground pad If the amber INCOMPLETE STIMULATION light goes out the instrument is working properly
40. otorpot should run smoothly from 0 milliamps to 10 milliamps If operating improperly check for proper alignment between the motor and the 10 turn potentiometer 4 4 MONITOR SENSITIVITY E quipment 1 Digital VOM Setup 1 A ttach the negative lead on the volt meter to monitor G round T P6 and the positive lead to T P5 Procedure 1 Za Turn the sensitivity Knob to position 1 TP5 should read as follows Position 1 35 mv R27 Position 2 b mv R28 Position 3 65 mv R29 Position 4 100 mv R30 4 5 CHEEK MUSCLE MOVEMENT SENSOR AND INSTRUMENT INPUT CALIBRA TION E quipment 1 Silverstein 58 M uscle M ovement Sensor 2 Digital VOM Procedure Part 1 see figure 9 1 With the sensor removed from the unit test the strain gages for proper resistance 2 DO NOT flex the sensor The two strain gauges should have approximately 350 ohms of resis tance to the common pin located in the center of the plug 3 Attach one lead from the ohmmeter to the center pin on the plug 4 Oneat atime touch the remaining lead from the ohm meter to each of the remaining 3 pins Two of the leads should equal approximately 350 ohms one should equal infinite ohms Silverstein Facial N erve M onitor Stimulator Service M anual version 2 1 Page 30 1 Plug sensor into the unit sensor body Procedure Part 2 see figure 5 outer strain gauge 2 Attach the positive leads of ei e the volt meter to
41. p enough to actuate the signal T his assures that the system is functioning and provides a new reference point with respect to current setting CAUTION Sounding of the signal indicates that the nerve is within the relative distance corresponding to the current setting Absence of the audible signal should not however be construed as assurance that the nerve is beyond the distance corresponding to the current setting The usual caution must be used in approaching the nerve even though the current setting may indicate that it is still a safe distance away Normal precautions must be taken to see that the lead wires do not become disconnected from the instru ments or from the output receptacles If a particular lead wire should be disconnected the signal would not sound regardless of the proximity of that instrument to the nerve IS Silverstein Facial N erve M onitor Stimulator Service M anual version 2 1 Page 16 NERVE IDENTIFICATION In differentiating a nerve from fibrous tissue the current intensity should be set at the minimum level which will evoke muscle contractions with the probe applied directly to the nerve W hen the probe is applied to other tissues at this same setting there should be no response If the current is set too high the nerve may be stimulated when the probe is applied to other tissues and the test will not differenti ate the nerve In differentiating two nervesor nerve branchesin close proximity the stimulating c
42. paralyzing drugs on nerve response EXPLOSIVE GASES T his unit isnot explosion proof Do not use this instrument in the pres ence of explosive gases BATTERY INDICATOR amp RECHARGING Check battery condition prior to and during use The monitor and stimulator circuits each have their own independent battery supply The monitor battery should be fully charged before use For full battery capacity charge for 36 hours before use or leave plugged in when not in use Yellow warning light illuminates when approxi mately 30 minutes to 120 minutes of battery power remains depending on current adjustment activity Do not use instrument if FAIL light is illuminated The stimulator battery will last approximately 50 hours and must be replaced if the green light is out Do not use the instrument without two positive green indications Do not attempt to recharge the monitor battery while stimulating because the stimulus output display and output control circuit will be disabled INSTRUMENT PERFORMANCE Caution must be exercised since there is no guarantee that the monitor system will always respond to nerve stimulus Current setting distance from nerve position and placement of sensor muscle response and other factors will affect operation of the monitor T he monitor is designed to assist in locating nerves N o guarantee of performance isintended or implied Silverstein Facial N erve M onitor Stimulator Service M anual version 2 1 Page 5 e SE
43. rent intensity and distance is nonlinear as shown graphically in figure 4 and a given increment of current intensity does not correspond to a fixed increment of distance In close proximity to the nerve a given increment of dis tance Ad corresponds to a smaller increment of current intensity Al than at greater distances from the nerve Al Figure 4 General relationship between applied current and distance from nerve Applied Current Al Ad Distance from nerve Silverstein Facial N erve M onitor Stimulator Service M anual version 2 1 Page 15 GENERAL PROCEDURE FOR USE OF THE MODEL SS During surgery the lowest possible current should be used especially in a wet field close to nerves With the bipolar probe on anerve a fraction of a milliampere should be sufficient W ith the unipolar probe high current settings will cause nerve and muscle response at a greater distance from the nerves FINDING A NERVE UNDERLYING OTHER TISSUE The selected probe is applied to the tissue bed overlying the nerve and the current intensity is turned up until muscle contractions are observed The probe is then applied at intervals along a line at right angles to the general course of the nerve At each point the current intensity is readjusted to the minimum level which will produce muscle contractions and the current reading is noted T he succes sive current readings will vary depending upon the square of the distance betwe
44. rm Di LED Jack 9 END 1 GNDA a Monitor 8 Title 3 Silverstein Facial Nerve Monitor Stimulator S8 D not used o z e Size Number Rev E C 3918 001 06 1 5 0 NA Date 11 18 2002 Drawn by TW ES Filename MainCB sch Sheet 2 of 4 B Cc D E F Silverstein Facial N erve M onitor Stimulator Service M anual A B D E F Remote Probe amp Front 8 4v Panel Up Down Switch T off Down U om j SI A S1 8 off A On o GNDA 8 4V ain 5 A MOTOR MOTOR E B ER GER 3 A 3 es SZ BEI RL ml K2 Y 2v 3 2v 3 o o q DF2E ocev ZL se Ep DF2E DC6V Z ES E A S g N 9 o EE Fl ES Ek wo MOTOR MOTOR 7 d A D Charging LED ES 3 Sleeve Battery B Red 2 Center 4 1 2 Charge Jack back view 3 8 4V MOTOR MOTOR Monitor Battery Indicator Motor drives a 10 turn 2 gang pot R66 S a Front section controls Stimulator Intensity Good y E 8 4V Rear section controls LCD display 00 Low T 22uF Disc S N 1 aod C20 3 gt Fail Adj 5 JAI 22329 ta 8 4V 84vV 8
45. ry Good indicator should illuminate this indicates adequate charge is present Do not use instrument without the green Battery Good indicator illuminated The yellow Battery C harge indicator illuminates when there is approxi mately 30 minutes of battery power remaining 3 3 STIMULATOR BATTERY CHECK E quipment needed none Set up none Procedure 1 Check the red and green stimulator battery indicators for the battery condition A green indica tion indicates adequate power remains A red indicator indicates that the stimulator batteries must be replaced WARNING Check the stimulator battery condition prior to and during use The stimula tor will function for about 10 hours once the red stimulator Battery Fail indicator illu minates Replace the batteries as soon as possible when the red Battery Fail indicator illuminates Silverstein Facial N erve M onitor Stimulator Service M anual version 2 1 Page 22 3 4 VISUAL INSPECTION E quipment none Setup none Procedure de 2 Check knobs for tight fit Check indicator lights for proper indication with no peripheral equipment plugged into the unit a Digital Display Illuminated b Monitor Battery Good indicator illuminated C Stimulator Battery Fail indicator off d Stimulator Pulse and Incomplete Stimulation Lights flashing Check thecharge circuit by turning the unit off and plugging the W R wall mount battery charger into
46. ses there is no current T he pulse width is 0002 seconds with an off time of 1998 seconds T here isa residual current of 05 mA when the digital display is at 0 N erve response to electrical stimulation is a function of current intensity through the nerve rather than of applied voltage Consequently precise control of current intensity is essential for quantitative evaluation of nerve response In the Silverstein 58 the voltage is automatically adjusted utilizing a constant cur rent output to compensate for any differences or changes in the patient stimulator circuit resistance so that the current is constant at any given setting of the current intensity display MONITOR The Silverstein N erve Stimulator M onitor model 58 is very sensitive It utilizes a high gain differen tial amplifier in conjunction with a mechanical strain gage muscle movement sensor to detect con tractions of the cheek muscle when the Facial nerve is stimulated The signal is then processed and presented in the form of an audio alarm beep or the flash of an indicator light T he sensitivity of the monitor is controlled by the sensitivity switch on the front panel Sensitivity position 1 is the most sensitive and position 4 is the least sensitive The unit can be muted with the use of the foot switch E Silverstein Facial N erve M onitor Stimulator Service M anual version 2 1 Page 18 Stimulator C urrent Output Pulse W idth Pulse Frequency Dial A ccuracy B
47. sulting muscle movement in the cheek and generates an audible or visual signal T he muscle sensor isa clothespin shaped device which slides easily onto the patient s cheek T his allows detection of super fine cheek contractions often finer than can be felt with the nurse s hand and allows drapes to remain over the face undisturbed Pulses current measured in amperes are delivered to the tissues using a pencil shaped probe T he current intensity can be accurately adjusted by the surgeon using push buttons on the probe A t very low settings the nerve will respond only when direct contact with the nerve is made By probing the surgical site and finding the lowest current which will elicit the least contraction the surgeon can locate the Facial N erve TheM odel 58 utilizes two separate circuits one for monitoring and one for stimulating T hese circuits may be used concurrently or separately The unit may be used as a stimulator only for plastic and reconstructive surgery orthopedic surgery or other procedures where visual or EMG confirmation of stimulus exists or with the monitor for proce dures involving the facial nerve FEATURES OF THE MODEL S8 1 Ultra sensitive muscle movement sensor and circuitry O ften detects contractions finer than can be felt with the hand 2 Sensitivity adjustment switch on front panel A Ilows for varying degrees of sensitivity depending on requirements of the surgical procedure 3 Convenient pr
48. t with the sensitivity set at positions 1 2 3 and 4 6 Test the sensor for shorts and open circuits when flexed The monitor bias with the sensor in stalled should be checked before testing for sensor shorts and open circuits T his is because the resistance of the strain gages are altered when the blades are flexed a small amount It takes a short time for the strain gage resistance to stabilize after being flexed See section 3 5 part a for procedure 4 6 CLOSING THE ENCLOSURE AFTER COMPLETING PRELIMINARY CALIBRA TION PROCEDURES Procedure 1 Remove any foreign material from inside the enclosure 2 Install the enclosure sides handle assembly on the instrument top panel by sliding it in to place Check for alignment of the front and rear panels in the groves of the case assembly 3 Install the case bottom feet and enclosure screws Tighten screws down after checking panel alignment A fter the unit calibration is complete and the case is closed it must then go through complete final checkout procedures see section 3 Silverstein Facial N erve M onitor Stimulator Service M anual version 2 1 Page 31 APPENDICES Board Layout and Schematic Parts List Suggested R eading E Silverstein Facial N erve M onitor Stimulator Service M anual version 2 1 Page 32 TOLER HES EXCEPT AN MITES Harap gy WED Op SILVERSTEIN HERVE RENT ATIT KO o menr STIMULATOR MONITOR G WR menicar eurcraomies co ITT CIRCUIT B
49. the 115 volt wall outlet and the power plug into the rear of the unit The red Battery Charge indicator should illuminate Check the electrocautery mute foot switch for nicks and cutsin the cable or other obvious physi cal damage Check the plug for proper fit into the foot switch jack on the instrument 3 5 SENSOR AUDIO ALARM AND FOOTSWITCH E quipment Silverstein Facial N erve M onitor Stimulator M odel 58 Cheek M uscle M ovement Sensor Foot Switch VOM 3 5A CHEEK MUSCLE MOVEMENT SENSOR 1 2 U nplug the sensor from the unit A ttach one ohm meter probe to the center conductor on the plug end of the sensor A ttach the remaining ohm meter probe to the opposite side of one of the two strain gages see figure 8 A pproximately 350 ohms should be obtained Flex the ends of the protruding bladestogether and then apart 1 8 CAUTION over flexingthe blade may cause damage to the sensor If any shorts or open circuits are detected the sensor must be repaired or replaced Place the ohm meter probe located on the outer plug pin on the remaining plug pin with a strain gage attached 350 ohms should be obtained See figure 9 Repeat step 3 5a 3 3 5B AUDIO ALARM AND FOOT SWITCH 1 2 3 4 Plug the Cheek M uscle M ovement Sensor into front panel sensor jack Plug the foot switch into the foot switch jack Turn the sensitivity switch to setting 1 Turn the unit on BH Silverstein Facial N erve M onitor Stimul
50. to 4 75 volts The current draw should equal approximately 20 mA at 4 75 volts If the stimulator current draw exceeds 30 mA return unit to WR M edical Electronics for repair 3 6B LCD CURRENT INTENSITY DISPLAY DRIFT CHECK Procedure 1 Turn unit on 2 After 10 seconds the numbers on the display should be stable 3 Increase and decrease the stimulator current intensity and let the digital panel display stabilize for a short time The display should not drift If display drifts return to WR Medical Electronics for repair Silverstein Facial Nerve M onitor Stimulator Service M anual version 2 1 Page 24 3 6C REMOTE PROBE PAD JACK AU X GRO UND JACK CHECK The remote probe is used to change the stimulator current intensity and acts as the active stimulating electrode E quipment 1 Remote Probe 2 Probe tip 3 Jumper wire Setup 1 Insert a probe tip into the chuck on the remote probe 2 Plugthe remote probe into the probe jack Procedure 1 Turn the unit on The pulse light and the Incomplete Stimulation Light should be flashing 2 Touch theend of the probe with a tip inserted to the PA D jack and then to the GND jack The Incomplete Stimulation Light should go out indicating a complete electrical path 3 Push the remote probe switch button nearest the probe tip The current intensity should in crease W hen pushing the switch button on the cord end the current intensity should decrease 4 Disconne
51. ty display down from 10 milliamps progressively to settings of 6 0 3 0 and 0 0 milliamps checking the pulse amplitude on the scope against the current intensity dis play to verify linearity Silverstein Facial N erve M onitor Stimulator Service M anual version 2 1 Page 26 4 Test the excess resistance light operation at 6 0 3 0 and 0 0 milliamps by disconnecting the IK resistor from the output W hen the IK load is removed the Incomplete Stimulation light should flash PART B Description W hen the stimulator load resistance is too great to supply constant current the Incom plete Stimulation light will flash E quipment 1 Oscilloscope 2 1K 1 4W resistor 3 100K variable resistor Setup See Figure 8 1 Connect alK 1 4 W resistor and a 100K variable resistor in series across the stimulator output 2 Set the variable resistor at 0 ohms 3 Attach the scope output across the IK resistor 4 Set the scope sensitivity to 1 volt division sweep at 0 1 milliseconds division DC coupled and the slope to negative 5 Adjust the current intensity to 5 50 milliamps Procedure Silverstein S8 1 Adjust the 100K variable resistor upwards until it EX brings the pulse amplitude on the scope back down to 5 milliamps 5 volts displayed on the scope CND ACTIVE 2 Adjust the current intensity down below 5 0 milliamps and then adjust it back to 5 0 and above Up to a setting of 5 0 milliamps
52. ual Part 10000 10003 11000 11002 11015 11023 11027 11031 11032 12005 12006 12008 12010 12011 12017 12021 12024 12028 14004 14012 14030 14036 14038 14057 14063 14064 14072 14073 14074 14075 14082 14087 14088 14094 14104 14113 14114 14115 14131 14133 Silverstein S8 Materials List Component Batt Alk AA Batt Nicad 8 4V 2200mAH Batt hold Bud for dual Nicads Batt holder Pactec w insert Case finished S8 Brack Case panel front S8 finished Case panel rear S8 finished M otorpot Coupler M otorpot M otor 6V 30RPM Cap Disc luF12 25V Cap Disc 22UF12v Cap Disc 220pF 3000v Cap Elec 47uF 50V Cap Elec 68uF 35v Cap Elec 4700uF6VDC Cap Poly 1uF 100v Cap Tant 1 UF35v Transformer M C5086A C B Auxport2 C B 58 Conn H eader 10 2 pin Conn Header 1 7 pin Conn H eader 10 8 pin Conn plug IDC 10 2 cond Conn plug IDC 1 7 cond Conn plug IDC 10 8 cond Conn Jack 4 conductor Conn Jack 7 pin hypertronics Conn Jack BNC Conn Jack Binding Post Small Black Conn Jack Phono Conn Jack miniature Scraft 42A Conn Jack power Conn Jack tip W hite Conn Pin for 6 pin con mol 0850011 Conn Pin female molex 02091143 Conn Pin male Irg tab mol 02092118 Conn Pin male sml tab mol 0209214 Conn Plug female M olex 03092022 Conn Plug male M olex 03091022 Print date 19 Jan 98 WU P FA DOP KH RFP k k BPP RP PP RP PPP RPP NN KH RP RPP WO HR RP RPP PRP BN KB Part 14146 15002
53. ure 2 Photograph showing hard Page with strips of adhesive tape A fter installing the mask covering mouth sensor to prevent drapes sensor but before draping theface cover the eyes from impeding muscle movement with eye protectors and then cover the sensor with a hard surgical mask to prevent the drapes from impeding muscle movement and to prevent the drapes from brushing up against the sensor which would cause alarm artifacts T he sensor wire should also be taped to the head The plug on the end of the sensor cable is plugged into the SEN SOR jack on the instrument panel A sensor should be connected to the SEN SOR jack at all times that the monitor isin use If a sensor is not connected the audible tone or light indicator may give false indication due to pickup of stray electrical noise or signals Each contraction of the cheek muscles causes a slight displacement of the white plastic blade on both sides of the cheek The strain gages on the blades transmit an electrical signal which actuates the audible device on the instrument Silverstein Facial Nerve M onitor Stimulator Service M anual version 2 1 Page 12 CHECKING THE SENSOR CIRCUIT You may test the functioning of the monitoring circuit and audible signal by lightly touching the sensor W hen the sensitivity switch is set to 1 the sensor will be so sensitive that if you set it on a flat surface and blow on it you will set it off You should be able to touch the patie
54. ure 3 virtually the en tire current flows through the PENIS nerve tissue consequently the muscle response occurs at a Figure 3 Probe applied to nerve relatively low current setting W hen the current is applied at a point remote from the nerve the current flow is diffused through the tissues and only a portion of the applied current actually reaches the nerve Inasmuch as the muscle response is a function of current intensity through the nerve a higher level of current is required to evoke a given muscle response than when the current is applied directly to the exposed nerve The current level required for a given response is generally proportional to the square of the distance between the nerve and the point at which the current is applied It isnot possible to set forth a definite numerical relationship between current setting and distance in millimeters from the nerve Rather the current settings must be considered as indicating relative distances as you work progressively closer to the nerve during a given procedure W hen the signal sounds at a relatively low current setting it indicates that the surgical instrument is correspondingly close to the nerve With experience the user will be able to relate current settings to approximate distances from the nerve Silverstein hasfound that 1 mm bone needs approximately 1 milliampere of current to stimulate the facial nerve It should be noted that the relationship between cur
55. urrent is applied to each in turn and the differential muscle response is observed It is essential that the current intensity be set low enough to stimulate only the nerve to which the probe is applied Too high a current could stimulate both nerves simultaneously NERVE EVALUATION W hen greater than threshold electrical stimulation is applied to an exposed nerve the presence or absence of muscle contractions indicates the viability of the nerve Stimulation of the exposed facial nerve with currents of 05 to 2 mA will indicate normal facial function postoperatively BEE Silverstein Facial N erve M onitor Stimulator Service M anual version 2 1 Page 17 10 MAINTENANCE INTRODUCTION Thissection of the manual covers the Silverstein Facial N erve Stimulator M onitor model 58 periodic maintenance and checkout procedures If you experience problems with your unit contact W R M edi cal Electronics Technical Service H otline Because of specialized circuitry only qualified biomedical personnel should attempt to repair the Silverstein Facial N erve Stimulator M onitor model S8 LIA OUTPUT INPUT PARAMETERS ST IMULATOR The Silverstein N erve Stimulator M onitor model 58 provides a square wave pulse which is adjustable from 05 mA residual current to 10 mA maximum current by means of a remote probe or a switch on the front panel Current intensity refers to the amplitude of the individual pulses not the average level of current Between pul
56. verstein Facial N erve M onitor Stimulator Service M anual version 2 1 Page 21 3 0 MAINTENANCE PROCEDURES Maintenance procedures in sections 3 2 through 3 6 must be done only when the instrument case is closed If calibration procedures are going to be preformed complete section 4 and then follow the maintenance procedures in section 3 2 through 3 6 for the final checkout 3 1 STERILIZATION GUIDELINES 1 The Remote Probe Remote Indicator Light and the M uscle M ovement Sensor must be gas sterilized only WARNING Steam sterilization will cause corrosion and discoloration of the Silverstein S8 peripheral equipment and possible malfunction may occur O nly the probe tips and the Indifferent Electrode PAD Cable can be steam sterilized 3 2 MONITOR BATTERY RECHARGE E quipment N eeded 1 WR wall mount battery charger Setup 1 Turn unit off U nit will not charge when unit ison 2 Plug wall mount charger into 115 volt wall receptacle 3 Plug the wall mount charger connector into the charger jack on the rear of the unit WARNING Do not attempt to recharge the monitor battery while stimulating or moni toring The unit will only charge when the unit is off Procedure 1 Thecharge light should illuminate when the charger is plugged in and the unit is turned off For full battery capacity charge the unit for 36 hours or leave the unit plugged in when not in use 2 When the unit is turned on the green monitor Batte
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