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Neurosign 100 Operating Manual 9883-23-P19

1. insert the electrodes and connect them to the Pre Amplifier Pod see Section 8 on Electrode Placement and Section 6 on the Pre Amplifier Pod for connections ensure that CHANNEL 1 and CHANNEL 2 switches are both OFF attach the Pre Amplifier Pod to the patient or bed and plug the cable into the PRE AMP POD INPUT Socket on the Rear Panel of the NEUROSIGN 100 connect the power lead to the power input module socket with the power switch at Q set power switch to 1 the orange LEDs will light turn on CHANNEL 1 and CHANNEL 2 as required with the electrodes connected and correctly inserted there should be no segments lit on the bargraph with the patient at rest For the first few minutes after needle insertion and whilst the patient is being draped it is normal for a few segments to flicker the muscle is irritated by the electrodes If segments are continuously lit check the location of the electrodes and the wiring to the Pre Amplifier Pod if all the wiring appears to be in order remove and resite the electrodes see Section 8 it is strongly recommended that the Impedance Meter available from the Company is used to check electrode placement before the patient is finally draped This device ensures that electrodes are placed in muscle tissue and also highlights any problems there may be with the electrodes themselves raise the front of the Neurosign 100 by altering the handle position in order to allow low level sounds to
2. 0 30Hz 0 2 1 0 0 1 2 0 3 5 0 0 05 CURRENT mA 5 CURRENT CONFIRM Lame mie NEUROSIGN 100 FREQUENCY This switch has two positions labelled 30Hz and 3Hz It is recommended PROBE that no neuromuscular block is used other than for intubating the patient and that a suitable anaesthetic protocol is implemented so as not to impede muscle movement in which case the frequency switch should be set to 30Hz The advantages of this are that because of the higher frequency the surgeon will need to stimulate the tissue for less time before correctly interpreting a positive response and also that the CURRENT CONFIRM circuitry will be able to check that the correct current has passed more quickly A neuromuscular block will reduce or eliminate the responses from mechanical distortion of the nerve which is the normal early warning to the surgeon If a neuromuscular block has to be used throughout the operation this switch should be set to 3Hz At this frequency the stimulation will overcome the block as long as it is not too deep although it may take 1 2 seconds to confirm that the correct current has been passed Please note that a high dosage of neuromuscular block must be avoided unless the patient needs to be paralysed for clinical reasons as this will significantly reduce the compound muscle action potential The Stimulator Probe Pod c
3. Axillary Musculocutaneous Suprascapula Medial pectoral Frontalis Orbicularis ocili Levator labii superioris Orbicularis oris Mylohyoid Muscle Brachioradialis triceps brachii anconeus extensor carpi radialis longus Flexor carpi ulnaris Pronator teres pronator quadratus flexor carpi radialis palmaris longus flexor digitorum superficialis Supinator extensor carpi ulnaris extensor digitorum extensor indicis aa extensor pollicis longus Aa Deltoid teres minor Coracobrachialis biceps brachii Supraspinatus infraspinatus Pectoralis major pectoralis minor Extensor carpi radialis longus Radial Anconeus 4 Extensor carpi X ulnaris Posterior interosseous Extensor A digitorum Deep Radial Fig 6 Flexible electrode for use in thyroid surgery Vocal cord Endotracheal tube The Magstim Company Ltd 9883 23 P19 Anterior view Ventricular fold false cord Sensing tracks of electrode Active area of electrode Electrode Brachioradialis Flexor digitorum f superficialis Electrode tail magstim Fig 4 Electrode placement suitable for submandibular gland surgery Biceps brachii Musculocutaneous Mm Medion Pronator f A teres WY Flexor i carpi N radialis Radial V Median ff i Palmaris f WY longus Median Yi Median a el F2 Black lines on tube mounted on fobs 8 OS Cuff Page 15 31st
4. The Neurosign 100 needs special precautions regarding EMC and needs to be installed and put into service according to the EMC information provided in Section 16 of this Operating Manual In addition portable and mobile RF communications equipment can also affect the Neurosign 100 The equipment should not be used adjacent to or stacked with other equipment and that if adjacent or stacked use is necessary the equipment should be observed to verify normal operation in the configuration in which it will be used The Magstim Company Ltd 9883 23 P19 Page 2 31st October 2005 Neurosign 100 SECTION 3 ATTENTION magstim WARNINGS AND PRECAUTIONS The Neurosign 100 is designed for use during surgical procedures and must only be used by qualified personnel who have carefully studied this Operating Manual and read this section This instrument is designed as an aid to surgeons in the identification and monitoring of motor nerves at risk during surgery It is not a replacement for experience in surgical decision making Before use ensure that the Voltage voltage selector is set correctly Only use fuses of the correct type and rating see Section 13 Serious damage may occur and a safety hazard exist if incorrect fuses are used or the wrong voltage is selected Do not twist the preamplifier cable around the pod when not in use as this may fracture the internal cores of the cable Coil the cable and use the retaining straps supplied with
5. to ground Autoclave gas sterilisation or chemical sterilant for Reusable Probes sterile single use Probes also available Single use sterile needle electrodes flexible polyester substrate conductive ink laryngeal electrode surface electrodes Reusable uninsulated stainless steel needle electrodes Sterilise as stated in appropriate section 2 Input noise of 8UV peak to peak CMRR greater than 100dB 10Hz to 1OkHz 3dB 1 5kV r m s to ground 10 1 Tuned filter system 6 5 inches 165mm 14W 31st October 2005 Neurosign 100 DISPLAY CONTROLS OUTPUT PORTS OTHER NOTE Bargraph Range Indicators magstim Twin 20 segment logarithmic trailing segment 30UV to 20mV p p Channel and 2 on off indicators Channel 1 and 2 artifact warning indicators Stimulation Current flow CURRENT CONFIRM indicator Stimulator Current Frequency switch 30Hz and 3Hz Stimulator Current control Loudspeaker Volume control Headphone Volume control Two amplifier ON OFF switches Channel Ident ON OFF switch Dual EMG output Headphone socket Stimulation Current Record Trigger output Safety Approvals Power Dimensions Weight Gain of 500 gt 16 ohm impedance 1V mA for data logging purposes TTL level EN60601 1 UL 2601 VDE 0750 MHW 230 240 100 120V 50 60Hz 50VA 290mm x 260mm x 100mm 6kg All specifications are subject to alteration The Magstim Company Ltd 9883 23
6. 0 2mA 0 5mA 3mA 0 5mA ImA 3mA 0 5mA 5mA SmA 0 5mA ImA 2mA ImA 3mA SmA 31st October 2005 Neurosign 100 magstim PROBLEM SOLVING PROBLEM No indicators light when power is switched on Background theatre noise obscures Neurosign 100 information Loud noise when using electrocautery No response at start of operation Little or no mechanically evoked responses Constant clicking noise and bargraph display with no stimulation ELECTRODE WARNING indicator on and beep sounding No response when using Stimulator CURRENT CONFIRM indicator stays lit after Stimulation is finished Bipolar probe is too big under the microscope and penetrates too far through tissue Difficulty in differentiating between the two channels Data logging is required The Magstim Company Ltd 9883 23 P19 Page 22 CURE Check Power Switch is set to 1 check power socket check voltage selector check unit fuses Increase volume or use headphones Attach the mute sensor and clip it to the electrocautery cable bipolar diathermy should not affect the Neurosign 100 but this can also be muted if necessary This is normal It may take a long time to reach the nerve or tissue to which the nerve is attached if in doubt use the stimulator set at a high current 2 3mA to check the area a faint clicking may be heard indicating the nerve lies deep to the probe If any neuromuscular block has been used anything other than direct ele
7. adjacent tissue The further apart the two probe tips the greater the current penetration and the less accurate the probe becomes Disposable Monopolar Probe P N 3602 00 sterile qty 10 Requires Ground Electrode P N 1705 00 This stimulating probe is intended for stimulating across the bulk of a tumour to determine whether a nerve is lying behind a structure and is not designed for accurate and selective nerve stimulation However accuracy can be improved by inserting the ground electrode as close as possible to the surgical area and by using the minimum current that will stimulate the nerve The Magstim Company Ltd 9883 23 P19 Page 30 31st October 2005 Neurosign 100 magstim REUSABLE ENT Forceps Stimulating Probe PROBES P N 9884 00 This pair of 150mm straight forceps will be of particular interest to ENT surgeons It enables the surgeon to continually check the area of work without having to pick up a separate dedicated probe Bayonet Forceps Stimulating Probe P N 9983 00 This pair of 250mm bayonet forceps is primarily intended for Neurosurgeons It fulfils the same function as the ENT forceps A 150mm pair of bayonet forceps is also available to order Straight Bipolar Stimulating Probe P N 1050 00 Intended for ENT surgeons this stimulating probe has a straight shaft with 100mm extending from handle to electrode tips It is better suited ergonomically to parotid and thyroid surgery but maintains
8. and the disposable monopolar probe Impedance Meter P N 9913 00 The Impedance Meter has been designed to ensure that electrodes are correctly placed in muscle tissue and not in fat The device measures the impedance between the electrodes and displays this on a bargraph with a simplified scale which does not _ require expert knowledge to interpret M mtemacsti M atte tow It is battery powered and may D therefore be used before the patient is draped and whilst electrodes can still sviches be repositioned if necessary It is completely self sufficient and does not need the Neurosign 100 to be connected It may be used to measure the impedance of intra ee muscular needles or surface electrodes and may therefore find applications in other departments LED Display 100k 10k 8k 7k 5k 3k 2k 1k 0 5k 0 1k POOR lt gt GooD M N Low Battery indicator Electrodes Dual Pod Switch P N 1037 00 This device enables two Pre Amplifier Pods to be L connected at the same time thus providing four gt channels for monitoring The Dual Pod Switch 3 activates either Pre Amplifier Pod individually with the unused Pod electrically disconnected or it combines the output of each Pre Amplifier Pod into a single channel Hence Pod A output appears on channel 1 of the main unit and the output of Pod B on Channel 2 This enables the monito
9. must come into contact with tissue in order to pass current If the area to be stimulated is very wet for example after being irrigated with saline solution much of the current from the Probe could flow through this liquid rather than through tissue The area to be stimulated should be made as dry as reasonably possible before stimulation Should the CURRENT CONFIRM indicator stay lit after stimulation this implies that there 1s still an electrical connection being made between the Probe tips probably by liquid picked up during the procedure This should be cleaned off before the Probe is used to stimulate tissue again The concentric Probes are very precise and have a diameter of only 1mm They are especially useful when working with the microscope and allow the surgeon to differentiate between the VII and VIII cranial nerves to stimulate within the Internal Auditory Canal or to stimulate fine fibres of the extra cranial nerve without stimulating surrounding tissue See Section 14 for further information The earth lead of the monopolar Probe should be connected to the patient via a sub dermal uninsulated reference electrode inserted at the operating site when required Alternatively the reference needle may be placed in the shoulder before the patient is draped This needle electrode should then be connected to the white socket on the Stimulator Pod and the monopolar probe wire attached to the blue socket The probe shaft is insulated to
10. or by using a damp cloth It may be difficult to obtain a result at the highest current setting so it is best to check the functionality of the Probe at the lowest current setting 0 05mA If the indicator lights the Probe is working Ensure that both electrodes come into contact with tissue not just the side of one electrode If the indicator does not light unplug the Probe and try another if this Probe works the first is faulty but if this still does not work the fault is likely to be in the Stimulation Pod Reasonable care of all items will ensure a long life but the components should be treated appropriately during the sterilisation and storage phases of the equipment s life The Magstim Company Ltd 9883 23 P19 Page 6 31st October 2005 Neurosign 100 CHANNELS 1 amp 2 ELECTRODE WARNING magstim These switches control each channel When the indicator is orange the channel is OFF when the indicator is green the channel is ON The bargraph for each channel will light showing the level of EMG activity Each bargraph is calibrated from 30UV to 20mV peak to peak In practice with the electrodes correctly placed no part of the bargraph should light unless the muscle is stimulated either spontaneously or by the surgeon either through manipulation or electrical stimulation of the nerve When EMG is detected the bargraphs rise when the EMG ceases the bargraphs fall However in order to allow the user to determine the level
11. s return pad often attached to the patient s thigh Thorough preparation of the area to ensure a reliable contact with low impedance 1s vital for patient safety Because the risk is related to the return pad and its impedance with regard to the body the risk is considered to lie exclusively with the use of monopolar electrosurgery Bipolar electrosurgery as its name suggests uses its own active and return electrodes in the same forceps It should therefore be considered whether monopolar electrosurgery is necessary when using nerve monitoring equipment In order to reduce any possible induced current in the needle electrode leads from stray RF emitted by the electrosurgical unit the electrode leads should be kept as far as possible from the unit In practice this means that the electrosurgical unit should not be positioned near the head of the patient Cables from the electrosurgical unit both active and return should also be kept as far as possible from the electrode leads especially whilst monopolar diathermy is being used Consideration should therefore be given prior to the surgery to the balancing of the risks of the surgery to the nerve being monitored and the possible risk of burns caused by any interaction between the electrosurgical machine and the Neurosign 100 The Magstim Company Ltd 9883 23 P19 Page 4 31st October 2005 Neurosign 100 SECTION 4 magstim FRONT PANEL LAYOUT FREQUENCY STIMULATOR CHANNEL 1
12. surgery it is suggested that two muscle groups are monitored one above the eye and the other in the lip For the lip the reference electrode coloured green should be inserted into the orbicularis oris above the vermillion border of the upper lip with the sensing electrodes coloured red and black inserted into the orbicularis oris below the vermillion border of the lower lip When placing the electrodes around the eye the sensing electrodes should be inserted in the frontalis with the reference electrode inserted in the upper cheek near the nose in the levator labii superioris It is important to keep the electrodes away from the masseter surgery of the cerebello pontine angle otherwise extraneous V nerve activity may be detected and misinterpreted For parotid surgery the electrodes must be spread to include the four major branches of the facial nerve See the diagrams on pages 14 and 15 The electrodes must not touch each other or a noisy or nil output will be obtained They should be inserted parallel to each other to reduce the risk of internal contact and approximately 5 10mm apart It will help to reduce noise and interference from other equipment if the wires are lightly twisted together as supplied The electrodes should be firmly attached to the patient using adhesive tape Movement of the patient s head or strong contractions can dislodge the electrodes and so the insertion of a slack loop in the electrode wires en rou
13. than as described in Section 11 may reduce the level of protection provided by the equipment Contact The Magstim Company Limited prior to uses not described in the brochure Before using the instrument check that there are no signs of physical damage to either the main unit the Pre Amplifier Pod the Stimulation Probe or the needle electrodes The Stimulation Probe must be inspected after autoclaving for any signs of physical damage or deterioration and the tip s checked They should be straight parallel and rounded Check the needle electrodes for physical damage Replace as necessary The use of needle electrodes when used near or in conjunction with electrosurgical equipment has the potential under certain fault conditions of the electrosurgical equipment to give rise to burns at the point of contact between the needle electrodes and tissue It is therefore strongly recommended that the instructions for preparation and use relating to the electrosurgical equipment are strictly adhered to and that the equipment itself 1s regularly checked for electrical safety and correct operation particularly in relation to any automatic impedance measuring or current sensing safety devices Only equipment which has an automatic cut out feature and measures the return pad impedance should be used in conjunction with the Neurosign 100 The particular conditions which could give rise to such a potential risk are concerned with the electrosurgical unit
14. the end so it is capable of very precise stimulation although it is difficult to control the degree of current spread The Probe should be touched onto the tissue until the nerve is located observing the same rules as to dryness as above A higher current setting may be required using a monopolar Probe do not exceed ImA as the higher current settings up to 5mA are for stimulating through bone only The monopolar probe is designed to be used to stimulate the tumour mass or where a large current spread is required It is not intended to be as accurate as the bipolar series of probes nor should it be used to try and stimulate through bone The Magstim Company Ltd 9883 23 P19 Page 17 31st October 2005 Neurosign 100 DISPOSABLE PROBES DISPOSAL magstim Some Probes have their tip s covered with a PTFE coating This insulates the tips other than the working surfaces to prevent current being shunted between the tips by liquid or tissue This coating is fragile and care should be exercised so as to avoid scratching it especially during the autoclaving process It is recommended that Probes are placed in two part bags before being put in the autoclave See page 21 for a table of suggested stimulation current settings together with maximum suitable values for a number of usual stimulation tasks The instructions for the surgeon when using a disposable probe are the same as for reusable probes Disposable probes are for single u
15. the pod Do not drop the instrument the Stimulator Pod or the Pre Amplifier Pod or otherwise permit any physical damage to occur Do not permit any liquid to be spilt such that it may enter the casing via the ventilation slots on the side or through the bottom of the casing Do not insert objects into holes or slots in the casing for cleaning purposes as this may cause damage Do not obstruct the ventilation slots Use a lint free cloth damped with alcohol to clean the instrument the Stimulator Pod and the Pre Amplifier Pod Store the instrument in a dry atmosphere within the temperature range of 5 C 30 C The reusable Stimulation Probe s and the reusable Needle Electrodes if specifically selected obtained from The Magstim Company Limited may be autoclaved maximum temperature 140 C Single use electrodes and stimulating probes are supplied sterile If there are any signs of damage to the packaging the electrodes or probes should be discarded No attempt should be made to re sterilise either used electrodes or probes or electrodes or probes found to be in damaged packing Needle electrodes should be removed from the patient by holding the heatshrink covering the end of the needle and pulling out the needle at the same angle as it was inserted The needles should not be removed by pulling the connecting lead This could cause damage and result in reduced performance or product life expectancy The shaft of a single u
16. Neurosign 100 Operating Manual 9853 23 P19 Neurosign 100 Table of Contents Section 1 Section 2 Section 3 Section 4 Section 5 Section 6 Section 7 Section 8 Section 9 Section 10 Guarantee Description Warnings and Precautions Front Panel Layout Rear Panel Layout Pre Amplifier Pod Preparations for Use Sensing Electrodes Electrode Placement Diagrams Stimulator Probe Pod Stimulation Probes magstim Page Number 11 12 13 14 16 17 Neurosign 100 Section 11 Section 12 Section 13 Section 14 Section 15 Section 16 Using the Neurosign 100 Interpreting Audio Signals Interpreting Neurosign Sounds Suggested Stimulation Current Settings Problem Solving Checklist Electrocautery Mute Maintenance and Servicing Voltage Selection and Fuses User Maintenance Preventative Maintenance Cleaning and Sterilising Single use Product Disposal Servicing Accessories Impedance Meter Dual Pod Switch Laryngeal Electrode Needle Electrodes Probes Carrying Case Equipment Trolley Specifications EMC magstim Page Number 19 20 21 21 22 23 24 24 24 25 25 29 26 21 27 21 28 29 30 33 33 34 36 1999 The Magstim company Limited Spring Gardens Whitland Carmarthemshire Wales U K All rights reserved No part of this manual may be reproduced without the written permiss
17. O Q LS o a PATIENT CONNECTION ELECTRICALLY ISOLATED ECOR The standard IEC power lead should be connected before the unit is switched on The unit is OFF when the switch is at the 0 position and ON when at the 1 position There are two fuses rated at T630mA for 100 120V operation or T315mA for 220 240V operation next to the power lead connector The fuses may be checked or replaced by removing the fuseholder cover This cover also provides access to the voltage selector Although it is unlikely that this will need to be changed unless the instrument is shipped to another country the mains voltage may be chosen by rotating the voltage selector and replacing the cover A legend displays the voltage selected when the fuse cover is replaced Do not select the wrong voltage or replace fuses with those of a different rating as severe damage may occur These outputs come after 10kHz filters but before the signal conditioning necessary for the audio section including the CHANNEL IDENT feature and so may be directly connected to an EMG recording instrument or a computer and the waveforms captured and printed if required The signal amplifiers have a gain of 500 and an output in the range 15mV to 10V peak to peak This TTL compatible output allows an oscilloscope external chart recorder or monitor to be synchronised to the unit in order to obtain waveforms or hard copies This facility may be used together with an EMG instru
18. October 2005 Neurosign 100 SECTION 9 CARE AND MAINTENANCE RATIONALE PROBE TESTING magstim STIMULATOR PROBE POD The Pod may be cleaned using an alcohol damped lint free cloth Do s not use water The cable and Probe Probe F connector may be washed in water as required Dry off the parts with a cloth and allow to dry completely N E U R OS I G N before storage The Pod may be Stimulator ETO sterilised if necessary Do not autoclave Sterilisation of the Pod Probe by any other means will invalidate the guarantee To enable disposable Probes to be connected a Stimulator Probe Pod is supplied The cable from the Stimulator Probe Pod should be taken back to the Neurosign 100 and plugged into the PROBE d connector The connector is a push y fit onto the socket it is in position posito d when a click is felt When a removing the plug do not pull on lt gt the cable as this may cause ony damage Always pull on the connector body The Pod should be placed in an accessible position or it may be placed out of reach if the Probe s 1s connected before the patient 1s draped Where possible place the Pod at the opposite end of the table to the surgery usually the feet This enables the Pod to be kept in the non sterile area where Probes can easily be attached or disconnected When connecting Probes ensure that the colour coding is observed this is especially important for m
19. P N 1705 00 Single use electrodes must be discarded after use Do not attempt to reuse Electrodes may be checked for correct location using the Impedance Meter Reusable Needle Electrodes non sterile all stainless steel 0 4mm CH1 and CH2 20mm qty 1 set P N 1178 00 Return electrode 20mm qty 10 P N 9957 00 The reusable needle electrodes are designed to have a long life but they will need to be replaced regularly They are prone to damage by their very nature and over time the surface of the stainless steel may oxidise which will give a poor signal to noise ratio If segments of the bargraph are lit and the electrodes are properly placed then this may be the problem It is safest to use the electrodes a maximum of 10 times and then replace them The Magstim Company Ltd 9883 23 P19 Page 29 31st October 2005 Neurosign 100 magstim DISPOSABLE Disposable Concentric Probe PROBES P N 3600 00 sterile qty 10 cl This stimulating probe is the most accurate of the three but has the least ability to stimulate through a layer of tissue Itis accurate to approximately 0 5mm In order to stimulate through any tissue covering the nerve the current must be increased Disposable Bipolar Probe P N 3601 00 sterile qty 10 This stimulating probe will stimulate through a small amount of tissue and yet remain accurate Current is passed between the two probe tips so the current is localised but will also flow through
20. P19 Page 35 31st October 2005 Neurosign 100 magstim SECTION 16 EMC Guidance and Manufacturer s Declaration Electromagnetic Emissions The Neurosign 100 System is intended for use in the electromagnetic environment specified below The customer or the user of the equipment should assure that it is used in such an environment Emissions Test Compliance Electromagnetic environment guidance RF emissions The Neurosign 100 uses RF energy only for its internal CISPR 11 function Therefore its RF emissions are very low and are not likely to cause any interference in nearby electronic equipment RF emissions The Neurosign 100 System is suitable for use in all CISPR 11 establishments including domestic establishments and those directly connected to the public low voltage power supply Harmonic Class B network that supplies buildings used for domestic purposes Emissions IEC 61000 3 2 Voltage fluctuations Complies flicker emissions IEC 61000 3 3 Guidance and Manufacturer s Declaration Electromagnetic Immunity The Neurosign 100 System is intended for use in the electromagnetic environment specified below The customer or the user of the equipment should assure that it is used in such an environment Immunity IEC 60601 Compliance Electromagnetic environment Test Test Level Level guidance Electrostatic 6 kV contact Floors should be wood concrete or discharge ESD 8 kV air Complies ceramic tile If floor
21. able should be connected to the socket marked PROBE unless the stimulator probe is not required for the procedure in which case it may be left unconnected It is a push fit in the socket and clicks home It 1s removed by pulling the plug from the socket do not pull the cable or damage may occur Always remove by holding the connector body do not remove using the cable or by twisting the connector sideways from the housing The Magstim Company Ltd 9883 23 P19 Page 5 31st October 2005 Neurosign 100 STIMULATOR CURRENT STIMULATOR TESTING magstim This control sets the current which flows through the Stimulation Probe and so through the tissue touched by the Probe It can be adjusted from 0 05mA 50uA to 5mA and consists of a narrow negative going pulse of 200us at a frequency of either 30Hz or 3Hz depending on the FREQUENCY switch setting Note that most of the travel of this control is at the lower levels of current below 1mA the higher levels are used for stimulating through tumour mass and bone Currents in excess of ImA should not be used directly on the exposed nerve in surgery involving the cranial nerves Although the minimum current setting varies dependent on the specific surgical procedure and on the individual patient s physiology the current may be set to 0 2mA as a basic control value but the user should be prepared to alter this in the light of experience There is a simple table suggesting suitable stimulation curre
22. anel will display an ELECTRODE WARNING light This means that there may be a problem with the electrodes for that particular channel which should be checked when convenient Provided that the problem is not severe 1 e the whole bargraph is not lit the instrument may continue to operate with reduced efficiency Refer to Section 8 for details of Electrode Placement If a click is heard each time a surgical instrument touches tissue this is likely to be caused by either metal to metal contact or by a build up of static charge on the surgeon or instrument This charge can be caused by the use of dissimilar metals in the instruments or by poor grounding and anti static precautions in the Operating Theatre In any event these artifacts will be minimised by good electrode placement Using swabs to insulate instruments from retractors will also help to reduce these artifacts There are four basic sounds from the instrument when used correctly The first is due to direct electrical stimulation and forms a series of pulses which last as long as the nerve is stimulated The volume of the signal will vary according to the current being passed the amount of neuromuscular block if any used and the integrity of the nerve The second is caused by direct manipulation of the nerve A brief mechanical contact caused by the surgeon working close to the nerve will be interpreted as a burst of clicks ending as the contact 1s removed The third is formed b
23. ated at a maximum output power not listed above the recommended separation distance d in metres m can be estimated using the equation applicable to the frequency of the transmitter where P is the maximum output power rating of the transmitter in watts W according to the transmitter manufacturer NOTE 1 At 80 MHz and 800 MHz the separation distance for the higher frequency range applies NOTE 2 These guidelines may not apply in all situations Electromagnetic propagation is affected by absorption and reflection from structures objects and people The Magstim Company Ltd 9883 23 P19 Page 38 31st October 2005
24. ation which is caused Train Compression of the nerve by the temperature difference between the Irrigation saline and tissue and is believed to be Heating ie laser or diathermy harmless a train response is a warning that the nerve has been irritated significantly and the surgeon should wait until the response dies down This type of response is important and should not be ignored Silence can often be worrying until the first Nerve not present positive response is obtained Frequently Nerve not stimulated surgeons expect to hear responses long before Silence Incorrect stimulation technique they are close to the nerve Normal anatomic Patient paralysed procedures for locating the nerve should be Nerve damaged prior to surgery followed the monitor will detect the nerve Electrodes in wrong muscle group when the surgeon comes close Silence is also a sign that the surgery is not irritating the nerve and as such is the ideal state of affairs SUGGESTED STIMULATION CURRENT SETTINGS Maximum all values have a tolerance of 20 or 25uA whichever is greater Between IAC and brainstem unmyelinated Myelinated facial nerve Recurrent laryngeal nerve Bone at the IAC Bone in middle ear surgery Bone in mastoid surgery Spinal motor root Stimulating tumour capsule to check for nerve fibres The Magstim Company Ltd 9883 23 P19 Page 21 setting SOuA minimum setting 0 5mA 0 2mA 0 5mA ImA 0 5mA 1 5mA 3mA
25. ation Probes and Reusable electrodes may be sterilised by gas sterilisation chemical sterilisation or autoclaving but the maximum temperature rating of 140 C should not be exceeded Reusable probes and electrodes should be cleaned after use following the hospital s policies and procedures e initially items should be washed under hot running water to remove blood and tissue contamination e items may be further cleaned using disinfectant and a lint free cloth e do not use an abrasive cleaner since this will damage the PTFE coating on some probes identified as a black coating near the probe tip e do not use excessive force when cleaning the probes The probes are fragile and should be cleaned with care cables should be washed but not pulled e there are no lumens in either the reusable probes or electrodes e reusable probes and electrodes may be washed by machine so long as the maximum working temperature of 140 C is not exceeded Items should be placed in a plastic or non metallic container if they are to be machine washed Do not place items on top of probes or electrodes e the exterior of the main unit the Pre Amplifier Pod and the Stimulator Probe Pod may be cleaned using an isopropyl alcohol BP 70 alcohol moistened lint free cloth Disposable items should be discarded after use following the hospital s procedures for disposal of contaminated sharps On no account should they be sterilised and reused as they
26. be heard plug the Stimulator Probe Pod into the front panel connector and locate conveniently near to the patient This is often at the foot of the table where the Pod can remain in the non sterile area for easy attachment of probes connect the Stimulation Probe to the Stimulator Probe Pod observing the colour coding The Magstim Company Ltd 9883 23 P19 Page 12 31st October 2005 Neurosign 100 SECTION 8 TYPES OF ELECTRODE ELECTRODE PLACEMENT magstim SENSING ELECTRODES Dependent on the procedure being monitored and individual preferences different electrodes may be used Surface electrodes may be suitable in some instances although in the majority of cases intra muscular non insulated stainless steel needle electrodes have been found the most satisfactory An electrode to monitor the vocal cords is also available see Section 14 The exact muscle location for the electrodes will vary according to the surgical procedure being performed It is important that the active electrodes are inserted within the muscle proper and are not merely resting in fatty tissue This could occur if an electrode were to be poorly placed or even passed through the muscle reaching fatty tissue on the far side The reference electrode should be placed close to the muscle itself to reduce artifact pick up but not in the same muscle group For monitoring the facial nerve during the resection of acoustic neuromas mastoid surgery or ear
27. ctivity near the nerve at risk will cause associated motor units to contract and the instrument will emit a distinctive sound the level of which is proportional to the stimulus applied to the nerve The nerve may also be directly stimulated using a small current via a Stimulation Probe There are a number of outputs available on the rear of the machine to enable an EMG instrument oscilloscope chart recorder or computer to be connected Dedicated software is available to enable an operation to be data logged and the waveforms analysed This instrument is supplied with a Bipolar Stimulation Probe Pre Amplifier Pod Stimulator Probe Pod Needle Electrodes Mute Sensor and the main signal processing unit For details on the availability of probe types and recording electrodes and their purchase please see the Accessories Section 14 on page 25 and contact either The Magstim Company Limited for the address please see Section 13 or your local distributor if outside the UK All interconnecting cables used with the Neurosign 100 including mains cables and accessory connections must be less than 3m in length If this length is exceeded EMC compliance may be compromised The use of Accessories transducers and cables other than those specified with the exception of transducers and cables sold by the manufacturer of the equipment as replacement parts for internal components may result in increased emissions or decreased immunity of the equipment
28. ctrical stimulation is unlikely to be heard the train of four test is not a guarantee that the neuromuscular junction is free of blockade Part of the bargraph has been lit for more than 20 seconds The electrodes may be poorly placed or faulty giving rise to artifact Check if possible and use the Impedance Meter before the patient is draped a Ifa neuromuscular block has been used set FREQUENCY switch to 3Hz b If neuromuscular block is deep a response is unlikely c Is the CURRENT CONFIRM indicator lighting d Increase current setting up to a maximum of ImA e Did the patient have a normal nerve pre operatively Check for liquid material between probe tips and clean as necessary Concentric probes may cause the indicator to stay lit for several seconds because of the proximity of the electrodes The concentric probes have a diameter of 1mm and also have very much reduced current spread making these probes suitable for use under the microscope and for example differentiating between VIIth and VIIIth cranial nerves Set INDENT feature to ON and ensure that the muscle group for each channel is noted Use EMG Channels Trigger and Stimulation Current Record to log activity as required using as oscilloscope or chart recorder or use Neuroscreen software package for analysis 31st October 2005 Neurosign 100 magstim SECTION 12 ELECTROCAUTERY MUTE SETTING UP DESCRIPTION The Neurosign 100 is fitted wit
29. ctrodes are used to monitor each muscle group The use of disposable needle electrodes is recommended in terms of performance and staff a and patient safety Two of these y electrodes are connected to the sp differential amplifier inputs ve gt and ve colour coded red and black and the third is connected to the reference input Ref colour coded green Care should be taken to connect the electrode wires correctly The best results will be obtained if the wires from each muscle group are lightly twisted together this reduces the amount of noise the wires pick up before they reach the Pre Amplifier Pod The use of the correct electrodes is absolutely essential and it is recommended that only electrodes obtained from the Magstim Company Limited are used The Company cannot guarantee the instrument s performance if these electrodes are not used They may be taped either to the bed or the patient as required For further information see Section 8 The Magstim Company Ltd 9883 23 P19 Page 11 31st October 2005 Neurosign 100 SECTION 7 magstim PREPARATIONS FOR USE The instrument should be prepared for use as follows clean the instrument with a dry cloth or a lint free material damped with alcohol place the Stimulation Probe and reusable electrodes if these are being used in an autoclave for the prescribed period see Section 13 Single use needle electrodes and stimulating probes are supplied sterile
30. etic Immunity The Magstim Rapid System is intended for use in the electromagnetic environment specified below The customer or the user of the equipment should assure that it is used in such an environment Test Test Level Level guidance Portable and mobile RF communications equipment should be used no closer to any part of the Neurosign 100 System including cables than the recommended separation distance calculated from the equation applicable to the frequency transmitter Recommended separation distance Conducted RF IEC 61000 4 6 80 MHz to 800 MHz Radiated RF 3 V m E V m IEC 61000 4 3 80 MHz to 2 5 GHz 7 800 MHz to 2 5 GHz d IN P Ey Where P is the maximum output power rating of the transmitter in watts W according to the transmitter manufacturer and d is the recommended separation distance in metres m Field Strengths from fixed RF transmitters as determined by an electromagnetic site survey should be less than the compliance level in each frequency range Interference may occur in the vicinity of equipment marked with the following symbol i NOTE 1 At 80 MHz and 800 MHz the higher frequency range applies NOTE 2 These guidelines may not apply in all situations Electromagnetic propagation is affected by absorption and reflection from structures objects and people The Magstim Company Ltd 9883 23 P19 Page 37 31st October 2005 Neurosign 100 magstim Field strengths f
31. eurosign 100 magstim Usage The electrode is sterilised using an appropriate technique The backing paper from the adhesive area of the electrode is peeled off and the electrode pressed firmly onto the endotracheal tube as shown in the diagram on page 26 the patient can then be intubated as normal Where possible a laryngoscope should be used to visualise the vocal cords and confirm that the active area of the electrode is lying between them It is strongly recommended that the Impedance Meter is used with this electrode since it is often difficult to confirm its correct position by sight alone The Meter ensures that the electrode touches the cords The cable assembly is connected to the electrode the electrode impedance is checked using the Impedance Meter and the cable is then connected to the pre amplifier pod The left cord will appear on Channel 1 the right cord on Channel 2 If only one side of the larynx is being monitored then only one half of the electrode need be connected however unless the remaining channel is to be used for another site 1t 1s recommended that both sides of the electrode be connected The electrode will detect the responses from electrical stimulation and given a suitable anaesthetic protocol the responses from mechanical distortion of the nerve Single use Needle Electrodes all stainless steel 0 4mm 20mm sterile qty 20 P N 1697 00 Return electrode 20mm sterile qty 20 for monopolar probe
32. h a sensor to enable the sound artifact from monopolar electrocautery to be muted It is not usually necessary to mute bipolar diathermy since the electronics of the pre amplifier pod can reject a high level of common input signals but occasionally a noisy diathermy machine or a poor operating theatre electrical environment may make this desirable Clip the blue Mute Sensor around the monopolar lead and connect the BNC plug to the socket marked Mute Sensor on the rear panel There is no further setting up to be done The easiest place to clip the sensor is usually near the electrocautery machine If the sensor cable is not long enough it may be extended using a BNC to BNC adaptor cable though such an extension should be avoided if possible and a suitable location allowing connection of all peripheral items without cables interfering with theatre staff movement is usually easily arrived at The mute will also cut out bipolar diathermy if required by clipping the sensor around the bipolar cable Both monopolar and bipolar leads can be clipped in together if both are to be muted Please note however that the Neurosign 100 will not normally be affected by bipolar diathermy and useful information about inadvertent stimulation due to proximity movement or thermal effects may be lost The mute is designed to cut out the speaker when monopolar electrocautery is used The bargraphs will show a high level of interference as will the EMG Output
33. han in accordance with this Operating Manual will void this guarantee and release the Company from any further guarantee obligations The Company will only accept responsibility for the safety reliability and performance of the equipment if e modifications or repairs are carried out by persons authorised by the Company and e the electrical installation of the room in which the equipment is used complies with local regulations and e the equipment is used in accordance with the operating instructions No statement in this Guarantee limits the statutory rights of a purchaser of this equipment in the United Kingdom The Magstim Company Ltd 9883 23 P19 Page 1 31st October 2005 Neurosign 100 magstim SECTION 2 __ DESCRIPTION The NEUROSIGN 100 Nerve Monitor has been designed to meet the needs of operating theatre staff by continuously monitoring motor neural pathways which are at risk during surgical procedures The instrument gives an audible interpretation of muscle activity which is sensed by needle electrodes placed into the relevant muscles controlled by those nerves to be monitored Note Muscle contractions are only possible if limited or no neuromuscular block is used The Neurosign 100 cannot be used in instances where the patient is paralysed The train of four stimulator should not be used as proof that any blockade has dissipated the Neurosign 100 can detect EMG well below the threshold of visible muscle movement A
34. have not been designed for this purpose and both the item s and the instrument s performance safety and efficacy will be impaired The Magstim Company Ltd 9883 23 P19 Page 25 31st October 2005 Neurosign 100 magstim SERVICING For further information or service contact The Magstim Company Ltd The Magstim Company Limited Spring Gardens Whitland Carmarthenshire SA34 OHR United Kingdom Telephone General Enquiries U K 01994 240798 International 44 1994 240798 Telephone SalesLine U K 01994 241111 International 44 1994 241111 Fax U K 01994 240061 International 44 1994 240061 email info magstim com Web Site www magstim com A service manual will be supplied to a qualified service repair station only after they have completed a service seminar sponsored by the Company Unauthorised removal of securing screws or any modification to the unit including the use of any unauthorised accessories will void the guarantee The Magstim Company Ltd 9883 23 P19 Page 26 31st October 2005 Neurosign 100 magstim SECTION 14 ___ ACCESSORIES The Neurosign 100 has a number of accessories which meet surgeons preferences or enable particular procedures to be carried out These accessories are listed below together with information for ordering items which have a limited life Please note that all electrodes and probes may be autoclaved with the exception of the laryngeal electrode single use needle electrodes
35. he Operating Manual contains ciruitry to remove the stimulus artifact when using monopolar stimulation The monitor essentially turns off for a period of 1 25ms after the stimulation pulse long enough to remove the artifact but short enough not to remove any response The Magstim Company Ltd 9883 23 P19 Page 10 31st October 2005 Neurosign 100 magstim SECTION 6 _PRE AMPLIFIER POD CARE AND The Pod may be cleaned using a lint free cloth damped with alcohol Do not MAINTENANCE use water as this will cause the instrument to give poor results until completely dry and may even cause damage PREPARATION The Neurosign 100 detects very small voltages within a number of motor FOR USE units In order to ensure that as little electrical noise as possible is amplified the instrument utilises a Pre Amplifier Pod which should be placed on or near the patient usually near the head either at the top rail of the operating table or at the side The Pod is fitted with a clip to enable CH2 CHI it to be attached to the rails on the NEUROSIGN table alternatively it may be laid PRE AMPLIFIER on the patient s chest or secured elsewhere as required The cable A from the Pod should be connected to the Pre Amp Pod Input socket CAUTION RF burns are a recognised risk of using needle electrodes in conjunction on the Rear Panel of the with electrosurgical equipment Refer to the operating manual for safety advice instrument Three ele
36. ion of The Magstim Company Limited Neurosign 100 magstim SECTION 1 GUARANTEE Equipment manufactured by The Magstim Company Limited The Company is fully guaranteed covering materials and workmanship for a period of one year from the date of shipment excepting those items detailed below The Company reserves the right to perform guaranteed services in its factory at an authorised repair station or at the customer s installation Reusable Stimulating Probes are guaranteed covering materials and workmanship for a period of 3 months from the date of shipment Reusable needle electrodes are guaranteed covering materials and workmanship for a period of month from the date of shipment Single use electrodes and stimulating probes are guaranteed to be free of defect upon use Sterilisation is guaranteed subject to the packaging being undamaged and the product being within the serviceable life as stated by the sterilisation date shown on the label The Company s obligations under this guarantee are limited to the repair or replacement of any defective parts without charge if the defects occur during normal service Claims for damages during shipment must be filed promptly with the transportation company All correspondence concerning the equipment must specify both model name and or number and serial number as it appears on the invoice Improper use mishandling tampering with or operation of the equipment otherwise t
37. ment Using the Trigger Output and the appropriate hardware and software the EMG Output can be captured by a computer The Company distributes a dedicated package for this purpose see Section 14 The Magstim Company Ltd 9883 23 P19 Page 9 31st October 2005 Neurosign 100 MUTE SENSOR STIMULATION CURRENT RECORD HEADPHONES PRE AMP POD INPUT OTHER magstim A Mute Sensor can be used with the Neurosign 100 to cut out the sound output during electrocautery The lead from the sensor should be attached to the Mute Sensor socket The sensor itself should be clipped to the monopolar electrocautery cable near the diathermy machine There is no adjustment available for the mute If the mute is not required do not connect the sensor and the Neurosign will operate normally but do not attach the sensor and leave it lying unconnected to the electrocautery cable since it will detect spurious signals and may cause the Neurosign 100 to cut out randomly Note that the bargraphs and EMG outputs are not affected by the mute and they will show a high level of artifact during electrocautery This output may be used to log the Stimulation Probe current setting with respect to time in conjunction with the Trigger and EMG Outputs It provides a voltage proportional to the Stimulation Probe current set on the front panel however the actual current flowing through tissue is affected by the quality of the contact between the Probe and tissue The v
38. nts on page 22 Further information on current settings for specific surgical procedures is outlined in the Procedure Sheets which are available from the Company or Distributor In order to enable the surgeon to know that the set stimulation current has been passed through the Probe an indicator labelled CURRENT CONFIRM is provided This indicator will light when the set current is passed therefore it will only light when the Probe is in good contact with tissue It provides positive proof to the surgeon that the correct current has been passed and also that the Stimulation Probe is functioning When the CURRENT CONFIRM indicator is lit the Stimulation Current Record on the rear panel provides a voltage proportional to the current set on the front panel this in conjunction with the EMG Outputs may be used for data logging See Section 14 for details of the computer software available The CURRENT CONFIRM indicator also provides a warning if the Stimulation Probe is faulty During the operation if the indicator stays on permanently check that the tips of the Probe are dry clean and are not touching and that there is no liquid material bridging them which could create an electrical path for current to flow If cleaning the tips does not cure the problem unplug the Probe If the indicator light turns off the Probe is faulty If the indicator does not light the Probe may be checked by shorting the Probe tips together either physically
39. of the response or to identify the channel the top segment of the EMG response remains lit for a period of several seconds before decaying When the unit is first switched on the bargraphs light and a beep is heard This allows the user to see that all the segments are working correctly The Neurosign 100 contains circuitry to detect the level of artifact present at the output Experience has shown that where the electrodes are poorly placed perhaps in fatty tissue rather than muscle or the incorrect electrodes have been used then a large amount of artifact may be present and can degrade the quality of the output available this possibility can be avoided by using the Impedance Meter described in Section 14 The Neurosign 100 detects this artifact and sounds a warning in the following manner For the purposes of this manual artifact can be defined as unwanted voltages present in the body or in the electrical environment of the Operating Theatre Each channel is monitored independently Artifact must be present continuously for a period of 20 seconds when the ELECTRODE WARNING light will illuminate and a short beep will repeat every 8 seconds until the problem is cleared Should the artifact fall below a certain level even for a moment the warning circuitry will reset and the process will start again There are three reasons why the ELECTRODE WARNING indicator may light e continuous monopolar electrocautery is being used for a period g
40. oltage at the Stimulation Current Record Output is only present when the CURRENT CONFIRM indicator is lit hence its value for data logging This output must not be confused with the Stimulation Probe the Stimulation Current Record Output on the rear panel is not on the isolated side of the electronics and must on no account be connected to the patient The Headphone connector will accept any 3 5mm stereo jack plug and headphones with an impedance of between 20 and 100 ohms Most lightweight headphones have an impedance of 32 ohms The volume of the headphones is controlled by the thumbwheel knob on the rear panel however this control operates after the main volume control on the front panel so both must be operated in order for the headphone output to function The output from the headphones is in mono even when both channels are used so that information is not lost due to any hearing difficulties of individual surgeons When using headphones the mute will be found to be only partially effective and some noise from electrocautery may be heard No sound will be heard from the Neurosign 100 itself The cable from the Pre Amplifier Pod is plugged into the PRE AMP POD INPUT socket The connector should be located in its socket and pushed firmly home To unplug the cable depress the tab and then remove the plug Do not pull on the cable to remove the connector as this may cause damage The Neurosign 100 which accompanies this revision of t
41. onopolar probes which will not function if wrongly connected It is important to realise that if two Probes are connected both Probes will be live In practice there is little risk of a Probe accidentally stimulating the patient but if the CURRENT CONFIRM indicator is lit even when the surgeon is not stimulating tissue then both Probes should be checked to remove the problem Probes must not be left standing in saline or allowed to contact other electrical devices The probe pod and stimulator can be checked by placing a damp cloth across the electrode tips with the current set to 0 05mA The CURRENT CONFIRM indicator should light If it does not there is a fault The Magstim Company Ltd 9883 23 P19 Page 16 31st October 2005 Neurosign 100 magstim SECTION 10 STIMULATION PROBES REUSABLE Both single use and reusable Stimulating Probes are available for use with PROBES the Neurosign These are as follows Disposable concentric probe bipolar probe and monopolar probe Reusable bipolar probe concentric probe and monopolar probe Surgeons may choose their probe type according to individual preferences and the demands of each procedure These are further described in Section 14 The use of the Probes varies slightly according to their type all reusable probes may be autoclaved The bipolar Probe should be plugged into the connectors on the Stimulator Probe Pod when required observing the colour code BOTH Probe tips
42. or must check the Reusable MAINTENANCE Stimulation Probe for any signs of damage It is important to a check that the spacing between the two wire tips is 2 3mm bipolar Probe only b ensure that the end of the wire tip s remain rounded and C that the cable and probe are in good mechanical condition with no splits tears cracks or loose connections If there are any sharp protrusions on the Probe tips the Stimulation Probe must not be used The needle electrodes must also be checked to confirm that they are in good condition Poor quality electrodes will give poor quality results Reusable needle electrodes should be used no more than 10 times before replacing unless they appear in good condition and have been inspected under a 20X microscope for oxidisation and tissue deposits On no account should single use electrodes or stimulating probes be reused The Magstim Company Ltd 9883 23 P19 Page 24 31st October 2005 Neurosign 100 PREVENTATIVE MAINTENANCE CLEANING AND STERILISING SINGLE USE PRODUCT DISPOSAL magstim Preventative maintenance is limited to visual inspection of the casing of the instrument Pre amplifier Pod Stimulator Probe Pod and associated leads and probes to check for any cracks or damage Such inspection must be carried out before each procedure and the instrument must not be used if there are any physical signs of damage No further preventative maintenance is necessary The Reusable Stimul
43. reater than 20 seconds injecting artifact into the patient The ELECTRODE WARNING indicator will extinguish as soon as the electrocautery Stops e the electrodes are poorly positioned or have become detached the use of the Impedance Meter will prevent the former whilst proper taping of the electrode leads as shown in the diagrams on pages 13 and 14 will reduce the risk of the latter e there is continuous EMG activity for more than 20 seconds such continuous EMG activity is not usually a good sign in that it represents continual irritation of the nerve The Magstim Company Ltd 9883 23 P19 Page 7 31st October 2005 Neurosign 100 VOLUME CHANNEL IDENT magstim When the indicator sounds the electrodes should be checked at the earliest convenient point in the surgical procedure if possible Experience has shown that correctly placed electrodes of the appropriate type will not give problems Care should be taken during placement see Section 8 and it should be remembered that strong muscle contractions could easily disturb the electrodes The electrodes should be securely fixed to the patient as well as properly located and inserted This knob controls the volume of the sound available from the speaker but does not affect the bargraph displays or the BNC outputs available at the rear of the machine The instrument utilises a compression technique so that small signals are amplified more than large signals This improves the sensitivi
44. ring of the VII IX X and XII nerves for example during acoustic neuroma surgery Other applications may arise in complex parotid spinal or brachial plexus surgery IAA BOTH PODS POD A CH 1 POD B CH 2 Li POD A POD B POD A ONLY POD B ONLY DUAL POD SWITCH The MAGSTIM Company Limited The Magstim Company Ltd 9883 23 P19 Page 27 31st October 2005 Neurosign 100 ELECTRODES magstim Pre Amplifier Pod P N 1719 00 formerly 9921 00 A second Pre Amplifier Pod is required if the Dual Pod Switch is to be used It is identical to that supplied with the Neurosign 100 Laryngeal Electrode P N 1011 00 to fit 8 or 9mm intubation tubes qty 10 P N 1035 00 to fit 6 or 7mm intubation tubes qty 10 Cable Assembly P N 1180 00 This electrode has been specially developed to enable the recurrent laryngeal nerve to be monitored during thyroid surgery It attaches to the endotracheal tube and is surgically non invasive However it is also useful during acoustic neuroma surgery for monitoring the X cranial nerve In such cases it will need to be used in conjunction with the Dual Pod Switch The electrode will also detect stimulation of the superior laryngeal nerves during radical neck dissections The careful use of anaesthetics which do not involve muscle relaxants is Electrode tail __ especially important when using this electrode during thyroid surgery as the surgeon will be close to
45. rom fixed transmitters such as base stations for radio cellular cordless telephones and land mobile radios amateur radio AM and FM radio broadcast and TV broadcast cannot be predicted theoretically with accuracy To assess the electromagnetic environment due to fixed RF transmitters an electromagnetic site survey should be considered If the measured filed strength in the location in which the Neurosign 100 System is used exceeds the applicable RF compliance level above the Neurosign System should be observed to verify normal operation If abnormal performance is observed additional measures may be necessary such as re orienting or relocating the Neurosign System P Over the frequency range 150 kHz to 80 MHz field strengths should be less than V V m Guidance and Manufacturer s Declaration Electromagnetic Immunity The Neurosign 100 System is intended for use in an electromagnetic environment in which radiated RF disturbances are controlled The customer or the user of the Neurosign 100 System can help prevent electromagnetic interference by maintaining a minimum distance between portable and mobile RF communications equipment transmitters and the Neurosign 100 System as recommended below according to the maximum output power of the communications Rated maximum output Separation distance according to frequency of transmitter power of transmitter m 150 kHz to 80 MHz 80 MHz to 800 MHz 800 MHz to 2 5 GHz For transmitters r
46. s are covered with synthetic material the relative IEC 61000 4 4 humidity should be at least 30 Electrical fast 2 kV for power Mains power quality should be that of Transient burst supply lines Complies a typical commercial or hospital environment IEC 61000 4 11 1 KV for input output lines Surge 1 kV differential Mains power quality should be that of mode Complies a typical commercial or hospital IEC 61000 4 5 environment 2 kV common mode Voltage dips lt 5 Ur Mains power quality should be that of short gt 95 dip in Ur Complies a typical commercial or hospital interruptions for 0 5 cycle environment If the user of the and voltage Neurosign 100 System requires variations on 40 Ur continued operation during power power supply 60 dip in Ur interruptions it is recommended that input lines for 5 cycles the Neurosign 100 System be powered from an interruptible power supply IEC 61000 4 11 70 Ur 30 dip in Ur for 25 cycles lt 5 Ur gt 95 dip in Ur for 5 sec The Magstim Company Ltd 9883 23 P19 Page 36 31st October 2005 Neurosign 100 magstim Power Complies Power frequency magnetic fields Frequency should be at levels characteristic of a 50 60Hz typical location in a typical Magnetic Field commercial or hospital environment IEC 61000 4 8 NOTE Ur is the a c mains voltage prior to application of the test level Guidance and Manufacturer s Declaration Electromagn
47. s from the rear panel This is to be expected valid monitoring will not take place during monopolar electrocautery although bipolar diathermy will leave the unit unaffected Should the mute not be required during the operation disconnect the BNC from the rear panel Do not simply unclip the sensor and leave it connected to the Neurosign 100 as it may detect spurious signals and cut out the speaker unintentionally The Magstim Company Ltd 9883 23 P19 Page 23 31st October 2005 Neurosign 100 magstim SECTION 13 MAINTENANCE AND SERVICING VOLTAGE The Neurosign 100 is preset at the factory to operate at 100V 120V SELECTION AND 230V or 240V A C as appropriate The following are the fuse ratings FUSE RATING SUPPLY FUSE S VOLTAGE Qty Size Rating 100 120V 2 20 x 5mm T630mA 250V 220 240V 2 20 x 5mm T315mA 250V The fuses may be changed by opening the fuse cover pulling out the fuse trays marked with an arrow replacing the blown fuse with one of the correct rating and by locating and pushing home the trays Replace the fuse cover The voltage may be selected by removing the fuse cover rotating the selector and replacing the cover A legend will indicate the voltage selected when the fuse cover is replaced Do not replace fuses with those of the incorrect rating or operate the instrument with the voltage selector set at an inappropriate voltage Serious damage may be caused USER At the start of each session the Operat
48. se concentric or monopolar probe may be bent once to an angle not greater than 30 Following bending the probe function must be re checked Once bent on no account should attempts be made to straighten the probe as this will cause it to fail Do not attempt to bend any other Neurosign Stimulating Probes as they have not been designed to withstand bending and will be damaged High levels of RF usually generated by electrocautery equipment may interfere with the operation of the Mute Sensor if this device is not connected to the electrocautery cable Do not connect the Mute Sensor to the Neurosign The Magstim Company Ltd 9883 23 P19 Page 3 31st October 2005 Neurosign 100 magstim 100 if the clamp is not to be attached to the electrocautery cable or spurious muting of the Neurosign 100 may occur Under extreme conditions it may be possible that the mute sensor or the pre amplifier may be affected by RF in which case a few segments of the bargraph may light In this case the offending piece of equipment should be identified and replaced alternatively an improvement may be achieved by moving the pre amplifier pod stimulating pod associated cables or the position of the Mute Sensor Any attempt to remove the securing screws will invalidate the guarantee There are no user serviceable parts inside There are high voltages present and there is the danger of electric shock if the casing is opened The use of this instrument other
49. se only and no attempt should be made to resterilise them Disposable probes are designed to allow the surgeon to bend the shaft of the probe up to a maximum of 30 This allows the surgeon to use the probe under a microscope Only one bend is permitted Do not straighten or over bend the probe or it may fail Dispose of the single use probe immediately after surgery using a sharps safety box The Magstim Company Ltd 9883 23 P19 Page 18 31st October 2005 Neurosign 100 SECTION 11 magstim USING THE NEUROSIGN 100 Before use refer to Section 3 for Warnings and Precautions to Section 7 for Preparations for Use Section 8 for Electrode Placement and Section 13 for Cleaning and Sterilising With all leads connected and the power switch set to 1 the instrument should be checked as follows Set CHANNEL 1 switch to ON the Orange indicator will change to Green If the electrodes are correctly placed no section of the bargraph should light Set the Volume Control to the desired level probably about half way through its travel If CHANNEL 2 is to be used as well set switch to ON position and check that no section of the bargraph is alight If any segments are permanently lit check the Electrode Placement see Section 8 If required the CHANNEL IDENT switch may be set to ON so that there will be a noticeable differentiation between the two channels The CHANNEL IDENT may be turned off at any time by setting the switch
50. te to the Pre Amplifier Pod is a wise precaution Refer to the diagrams on page 13 and 14 for the suggested placement of electrodes In procedures where it might be useful to be able to monitor several muscles over a long period of time the Neurosign 100 Dual Pod Switch may be used This allows two Pods to be connected and the user may switch between the two Pods This enables four muscles to be monitored see Section 14 The Magstim Company Ltd 9883 23 P19 Page 13 31st October 2005 Neurosign 100 magstim ELECTRODE PLACEMENT DIAGRAMS Fig 1 Electrode placement for acoustic neuroma mastoid and ear surgery Frontalis ve we CH 1 ve Le Reference Orbicularis Incorporate a oculi slack loop when taping each electrode to the patient is Reference CH 2 7 ve N ve Levator labii superioris ve a i CH 1 lt lt ve N Reference Fig 2 Electrode placement suitable for Parotid gland surgery Reference CH 2 7A ve N ve ve POD A CH 1 e ve POD A CH 2 Reference Pod A only ve POD BCH1 Vt Fig 3 Electrode placement suitable for 4 Channel monitoring of the facial POD B CH 2 ve nerve requires Dual Pod Switch Ve The Magstim Company Ltd 9883 23 P19 Page 14 31st October 2005 Neurosign 100 Reference for CH 1 Pa Reference CH 2 ve N ve Fig 5 Brachial Plexus muscle sites Nerve Radial Ulnar Median Posterior interosseous
51. the accuracy and penetration of the standard bipolar probe It can be used in conjunction with the concentric probes to deliver both highly precise stimulation of fine fibres and the checking of larger areas for the presence of neural tissue The Magstim Company Ltd 9883 23 P19 Page 31 31st October 2005 Neurosign 100 SUNDRY magstim Concentric Bipolar Probe P N 1060 00 IT P serr A Neurosurgical probe with a special concentric design which allows very precise stimulation of the nerve It has an overall diameter of only 1mm with the stimulating electrode having a diameter of 0 4mm and consequently it is very accurate The bayonet shaft has a length of 125mm extending beyond the handle This makes it ideal for use under the microscope The probe will allow the surgeon to discriminate between the VII and VIII cranial nerves It has a limited ability to penetrate tissue and should be used in conjunction with other probes Concentric Bipolar probe P N 1061 00 A probe designed primarily for ENT surgeons utilising the concentric principle It is short and straight with 75mm of the shaft extending beyond the handle allowing easy stimulation of small fibres for very precise stimulation Again it has a limited ability to penetrate tissue and should be used in conjunction with other probes Instrument Adaptor Kit P N 1043 00 This simple cable allows surgical instruments to be electrified and used as stimulators This is par
52. the lowest level which produces a satisfactory result As a guideline where the nerve is unmyelinated a brisk response should be available at a setting of 50uA and where the nerve is myelinated the setting is likely to be 0 2mA Nerves other than the vir may react in different ways for example the recurrent laryngeal nerve often requires 0 5mA to ImA The Magstim Company Ltd 9883 23 P19 Page 19 31st October 2005 Neurosign 100 INTERPRETING AUDIO SIGNALS magstim When the Stimulation Probe comes into contact with a neural pathway the associated muscle will contract and the instrument will register a response dependent upon the level of stimulation the contraction may be below the threshold of visible movement The sound level is governed by the Volume control but the bargraph display will show the actual level of activity irrespective of the setting of the Volume control The bargraph has a peak hold facility which keeps the top bar at the maximum signal level for a period of 7 seconds after the response This allows the user to examine the machine once a response is heard to determine which channel was stimulated The volume level is a matter of personal choice but there is useful information even during quiet periods in that as the surgeon works closer to neural fibres so small reactions are picked up and provide a degree of early warning Should the instrument begin to beep at any stage of the procedure the front p
53. the recurrent Conducuye Tracks laryngeal nerve very quickly Because the nerve will be at risk very soon Adhesive backed area after the start of surgery insufficient time may have elapsed for any paralysing agents used during intubation to have worn off and either allowance must be made for this by the surgeon or the intubation procedure should be changed if possible and if appropriate for the patient If it is necessary to paralyse the patient during the surgery the electrode will still detect direct electrical stimulation of the nerve but no mechanical responses will be elicited D Black lines ae Cuff The laryngeal electrode consists of an electrode and a cable assembly The electrode is available in two sizes to suit different sexes and age groups The electrode is supplied in boxes of 10 non sterile but each may be sterilised disinfected by ETO or by immersion in CIDEX ASEP or chlorohexadine for 10 to 15 minutes and followed by washing with copious amounts of sterile water The cable assembly may be washed and sterilised using either a chemical sterilant or by ETO if this is considered necessary but it will normally be outside the sterile field The cable assembly is available separately and connects the electrode to the pre amplifier pod It will have a long life if treated with care 1 Not available in the USA and some other countries The Magstim Company Ltd 9883 23 P19 Page 28 31st October 2005 N
54. ticularly useful when paring tumour off the nerve and constant stimulation is needed to check the position of the cutting edge Instruments are also available but any which are to be used in this fashion must be insulated apart from the stimulating edge and should have a 2mm hole drilled in the end A needle electrode is supplied to act as the return path Both the cable and the needle electrode are reusable and may be autoclaved Headphones P N 130011 This feature is included in the Neurosign 100 so that the surgeon can hear responses when drilling through the mastoid process or internal auditory meatus when the background theatre noise may be high The headphones have been chosen to provide a high output with good low frequency response A 4m extension cable is supplied with the headphones The Magstim Company Ltd 9883 23 P19 Page 32 31st October 2005 Neurosign 100 magstim Carrying Case P N 1176 10 This handy carrying case has ample room to store the Neurosign 100 all its component parts and accessories such as the Impedance Meter Dual Pod Switch and an additional Pre Amplifier Pod It has a shoulder strap and two external side pockets and one large external front pocket The colour is a distinctive dark blue with the Neurosign 100 logo marked on the case to ensure that it is not mislaid or diverted Equipment Trolley P N 1175 00 The trolley has large wheels for safety and folds up for storage It has a useful basket
55. to the OFF position If only one Channel is being used the CHANNEL IDENT should be set to OFF The FREQUENCY switch should be set to 30Hz except where the patient is to be paralysed for the whole procedure In these cases the FREQUENCY switch should be set to 3Hz and the surgeon should be made aware that responses due to electrical stimulation will sound slow and may be weak in comparison to situations where the patient is not paralysed The surgeon must also be made aware of the fact that should the patient be paralysed there will be no mechanically elicited responses There should be no sound or display from the instrument until the procedure reaches the point where a neural pathway can be stimulated other than that caused by spontaneous firing of the nerve At this point the integrity of the system can be confirmed by use of the Stimulation Probe The Stimulator Current should be set to the minimum level appropriate for the procedure and the area checked for nerve fibres Should there be no reaction or only a weak reaction the Stimulator Current may be increased The control is calibrated in a logarithmic manner so most of the rotation of the control is between 0 05mA and ImA with only a small rotation required to take the current to 5mA A strong reaction is normally available at a current of 0 2mA so care should be exercised and the procedure should start with the current at its lowest setting The current setting should always be at
56. ty of the instrument at low signal inputs whilst still giving powerful warning of very high input levels occasioned by either direct stimulation or mechanical distortion of the nerve The volume control cannot be set to zero this is a safety feature in case the control is accidentally set to the minimum and the surgeon is not aware of the fact In most circumstances the surgeon will find it desirable to monitor two sets of muscles together If it 1s important however to be able to differentiate between the two nerve branches being monitored the CHANNEL IDENT switch should be set ON This introduces a different texture to the sound output for each channel This difference is only applied to the speaker the outputs available for connection to external devices do not include this Channel Identification colouration The Magstim Company Ltd 9883 23 P19 Page 8 31st October 2005 Neurosign 100 magstim SECTION 3 REAR PANEL LAYOUT OFF MAINS CONNECTOR EMG OUTPUTS TRIGGER OUTPUT GROUNDING RELIABILITY CAN ONLY BE CAUTION TO REDUCE THE RISK OF ELECTRIC MUT STIMULANON Oo ACHIEVED WHEN THE EQUIPMENT IS SHOCK DO NOT REMOVE COVER REFER URRENT R D CONNECTED TO A HOSPITAL GRADE RECEPTACLE SERVICING TO QUALIFIED SERVICE PERSONNEL ER SAI7i7 SS eee O J FUSE ACCESS MADE IN BRITAIN dd l The MAGSTIM Company Limited COVER BELOW AE had Seer HEADPHONE SERIAL NO 00235XX92 PRE AMP POD INPUT 0 0
57. underneath for storing probes electrodes manuals and pods and is ideal for using with the Neurosign 100 Specifications Open 0 5m Depth x 0 5m Width x 0 8m Height Closed 0 2m Depth x 0 5m Width x 0 8m Height Material Bright polished stainless steel Maximum load 50kg Weight 9 kg The Magstim Company Ltd 9883 23 P19 Page 33 31st October 2005 Neurosign 100 SECTION 15 R AMBIENT CONDITIONS STIMULATION PROBES ELECTRODES AMPLIFIER magstim SPECIFICATIONS This equipment is classified as Class 1 Type BF Permissible Environmental Conditions for Transport Ambient Temperature Range Relative Humidity Range Atmospheric Pressure Range 5 C to 60 C 10 to 80 Non Condensing 50kPa to 106kPa Operating and Storage Conditions Operating Temperature Range Storage Temperature Range Relative Humidity Range 5 C to 30 C 5 C to 40 C 30 to 70 Non Condensing A box of sterile single use probes is included with each instrument as required Probes may be purchased separately see Section 14 Stimulator Output Stimulator Frequency Waveform Isolation Probe Sterilisation Type Channels Frequency range Isolation Audio compression ratio Channel ident Speaker Amplifier output The Magstim Company Ltd 9883 23 P19 Page 34 Constant Current SOWA SmA 20 or 25uA whichever is greater 30Hz or 3Hz 200us pulse width negative going pulse 1 5kV r m s
58. y a regular repetitive train of clicks lasting several seconds or even minutes This train of pulses may be caused by mechanical manipulation of the nerve i e compressing or stretching it or by a change in temperature as when irrigating the area with saline or heating the area by diathermy or with a laser Unless the train of pulses is caused by irrigation it may be advisable to allow the nerve to recover before continuing with the procedure The fourth is an absence of sound Because the instrument registers the voltage in the muscle it follows that the muscle must contract in order for a sound to be heard The muscle may not contract for a variety of reasons the nerve may not be stimulated the nerve may be damaged or transected or any neuromuscular block may be too deep The Magstim Company Ltd 9883 23 P19 Page 20 31st October 2005 Neurosign 100 magstim INTERPRETING NEUROSIGN 100 SOUNDS DESCRIPTION CAUSES TYPICAL SOUND Regular clicks at the Stimulator frequency Pulses Electrical Stimulation when using the Stimulator Probe a weak sound may indicate that the nerve lies behind the stimulated tissue Burst Direct Surgical Manipulation Clicks synchronised with surgical manipulation of the nerve or tissue to which the nerve is attached often sounds like the rustling of tissue paper Continuous clicks lasting several seconds or even minutes after the end of some surgical Stretching of the nerve action Except for irrig

Neurosign 100 Operating Manual 9883-23-P19

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