Peripheral nerve stimulation - Outcome Medical of Georgia

Peripheral nerve stimulation in thetreatment of intractable painJAMESN. CAMPBELL M.D. AND DONUN M. LONG M.D. PH.D.Department of Neurosurgery. JohnsHopkinsHospital. Baltimore. MarylandPeripheral nerve stimulating deviceswere implanted for pain control in 33 patiewith variety of disabling chronic pain conditionswhich had persisted despite ustmedical and surgical therapy. The implantswere placed on major nervesthe areaof the patientspain.innervatiRecordswere obtained of each patientsstatedfrom pain produced by nerve stimulation along with assessmentsof narcowithdrawal ability to return to work sleep pattern and relief from depression. Bason these five criteria 17 patientswere judged to be treatment failureswhile eighttientshad excellentwereresultsand seven had intermediate results. Twelve of the failurin patientswith either low back pain with sciatica or pain from metastaticease. The most dramatic successesoccurred in patientswith peripheral nerve trauirThe incidence of complicationshas been low and two patientshave usedstimulator foryearswithout adverse effects. Techniquesof peripheral stimulator itplantation possible mechanismsof action and conclusionsregarding peripheral netstimulation in the treatment of chronic pain are discussed.rdKEYWORDSintractable pain nerve stimulation0.THE optionsfor treatment of intractable pain are few. Until recent yearsthey have been confined to psychotherapy narcoticsor variousneural ablative promethod has provedcedures. None of these methodssatisfactory for long-term patient management. The finding of Wall and Sweee in1967 that percutaneoussensory nerve electrical stimulation could produce hypesthesiasdistal to the point of stimulation thereforeencouraged interest in the possibility thatneural stimulation could be used to treat intractable pain. The two most common techniquesdescribed are transcutaneouselectrical stimulation and spinal cord stimulationviaelectrodes placed over the dorsal columns.317Transcutaneousstimulation has the. disadvantage of being cumbersome moreoveradequatestimulation of the involved ncrvcproducesdiscomfort referred to the overing skin. Spinal cord stimulation has the diadvantage of requiring major operation.addition there are often difficultieswith ide.placement of the electrodesand di.turbingly high number of long-term technicfailuresoccur due in part to scar formaticaroundpainthe clectrodes.3third method of neural stimulation fccontrol involvesimplantationof peripFera nerve stimulatorsPNS. Bipolar dcctrodesare attached tothe field of innervation containswhichmajor nervesof whicthe regionpain arisesand are then connected toradiofrequency receiver placed under thskin. The electrodescan then be activatedtransmitting device connected to an antenntaped in place over the receiver.In the following report we describe thresults obtained in seriesof 23 patientswhi692 J.Neurwurg. Volume 45 December. 1973015

J.N. Campbell and I. M. Longdirected at the assessment of five variablesI. Each patientsown impression of howmuch pain relief he was receiving fromuse of the stimulator device2. Patternsof drug use3. Sleeping habits4. Activity level5. Psychological well-being.In addition inquiriesas to patternsstimulator use and adverse effectswere made.Follow-up information was also obtainedon nine of 10 patientswith PNS implantationdone at the University of Minnesota. Patientchartsandinformation obtained from the patientspersonal physician were used assourcesof thisinformation.Summary of PatientsJohnsHopkinsHospital Seriessummaryof the resultsfor each patientis contained in Table along with thepatientsdiagnosistype of stimulator implanted and length of follow-up period. Anexcellent result is defined by the followingcriteriaI. The patient must continue to require theuse of the stimulator for pain relief thusallpatientswithofspontaneousremission are excluded. Only one patient had spontaneousremission andthispatient was consideredtreatment failure by other criteria.2. Analgesic use must be confined to occasional use of Tylenol acetaminophen oraspirin.3. All patientsmust have been able toresume their usual occupation or at lcast beactive at level compatible with their neurological deficit.4. All patientswho previously had beendepressed because of their pain must have hadan improvement in mood.5. Sleep disturbance previously associatedwith pain must have ceased.6. Each patient must have felt that use ofthe peripheral nerve stimulator providedmore than 50% relief of his pain.Of the 23 patientsfour were judged to havehad excellent results. Another five patientsmet some of these criteria and were judged tobe partial successes. The remaining 14 patientswere treatment failures. Eleven of thetreatmentfailuresoccurred in patientswithlow back pain syndrome with sciatica or painfrom metastatic disease. One of the treatmentfailureswas in patient Case who had hadtraumatic amputation of hs thumb withresulting dysesthesias.Trialsof percutaneousstimulation preoperatively had failed torelieve his pain however because of hisdesperate situation brachial plexusstimulator was implanted although thechancefor successwas thought to be poor.One of the four partial successpatientsCase had had nerve trauma in the handand had undergone number of handoperations. He had two distinct typesof painthe worse being sharp jabbing pain and theother burning dysesthesia. The stimulatorrelieved the former pain and allowed him toreturn to work. Subsequent to the stimulatorimplantation he had sympathectomy andinternal neurolysisof the median nerve whichhas relieved his second type of pain. He isnow able to resume normal life without useof analgesicsbut requiresthe use of thestimulator to control the sharp jabbing painto which he is still subject.Another partial successwas patient whohad had excellent resultsfor monthsbutthen developed an incomplete radial nervepalsy and partial return of pain in the areasdistal to the brachial plexusstimulationdevice. Thispatient is currently in the hospital undergoing diagnostic evaluation. Theother partial successeswere in patientswithlow back pain sciatica tvho claimed substantial pain relief with use of the stimulatorbut who were unable to resume normal livesbecause of remaining pain.Two of the excellent resultsoccurred in patientswith peripheral nerve trauma which hadfailed to improve despite multiple operations. Another was in patient with brachialneuritissecondary to radiation therapy forbreast carcinoma. The fourth case was inpatient who continued to have severe armpain following removal of cervical rib causing brachial plexuscompression.There was one infection which occurred inthe area where the receiver had been implanted on the anterior chest wall. The patientCase had had radical mastectomyandradiation therapy to thisarea and the infection probably resulted from poor healing. Shehas done well after relocation of the receiver.There was one noninfectioustissue reaction.Thiscomplication presumably reflectsanidiosyncratic reaction to the PNS implant as694J. iVcurosurg. Volume 45 lkcenbcr. /9763016

Nerve stiniulation for intractable painTABLEResultsof peripheral nerve stimulator imp/at in 23 patientstoLiushe1tsStimulatorAge SexDiagnosisNo.Location155 brachial arm pain after cervicalrib removalComplications32 brachial crush injury to elbow relict foryr thenwrist weaknessRu1tFollow-Upmosnone excellent 12andreturnpartial painpartialsuccess1327 brachial ringer injury to hand none partial12adthetor51 brachial traumatic amputationof thumb71 brachial brachial plexitisradiotherapyfromfornoneinfectionremovedPNSthensuccessfailureexcellenttotortndich33 medianbreasttraumaticcarcinomaof forefinger37 median wrist crush withamputationmedian nerve injuryreimplantednoninfectiotisnonetissue reactiontechnicalfailureexcellent1017 NI ulnar elbow crush with ulnar none excellent 12jsetheambut10 5711 54nerve injury60 sciatic metastasisto spinebilateralsciaticsciaticcoloniccarcinomametastasisto spine hiphypernephromametastasisto hipadrenalcarcinoma12 33 sciatic hyperesthesia leg paincausenone failure 12nonefailure17nonefailure13none failure II13 56 sciatic foot pain cause none failure 1514 43 sciatic low back pain syndromewith sciatica15 38 sciatic low back pain syndromewith sciatica16 42sciatic low back pain syndromewith sciatica17 56sciatic low back pain syndromewith sciatica18 43 Nt sciatic low back pain syndromewith sciaticanonenonenonenonesorenessof receiverin areapartialsuccesspartialsuccesspartialsuccess14failure 12failure 1419 32 NI sciatic low back pain syndromewith sciatica20 53 sciatic low back pain syndromesciatica21 78 sciatic low back pain syndromewith sciatica22 38 sciatic low back pain syndromeWith sciatica23 51 sciatic low back pain syndromenone failure 13none failure 16none failure 13none failure 12none failure 16withsciaticat.ntr.a.no source of contamination could be found.Another patient had considerable tendernessin the area of the receiver leading to removalof the implant. There were no objective signsof inflammation.The use of the stimulator by patientseither the excellentor partial successcategoryinchanged little from the time immediatelyafter implantation to the time of follow-upexamination. Almost all of the patientsusedthe device more than 12 hoursday. All usedsufficientpower output to produce light-tosttong buzzing sensation which radiated tothe area of pain.693I. iVeurosurg. Volume 45 December. /976ac.scr 4L ..

J.N. Campbell and D. Ni. LorTABLEResultsof peripheral tierve stimulator irnplanta in the University of tIhnesuta .ccriesAgeSnrnuIiturDiagnosisComplicationsResultFollow-U47 NI uhiar gunshot wound innone excellent 68elbow ulnar palsy42 ulnar ulnar pain fromnone excellent 63olecranon fracture42 ulnar tardy ulnar palsy none excellent 4641 ulnar tardy ulnar palsy none xccllent 5419 sciatic hip dislocationsciaticinjurynone partial 44successnone failure 4459 sciatic spine injurysciatic palsy31 brachial traumatic amputationof arm stump pain57 brachial traumatic amputationof arm stump pain64 sciatic amputation above theknee vascular diseaseneuropathy stumpinfectionremovedPNSthen failurerecent 44reimplantedwire disconnected initially excellentrcimplantedlost to follow-upmuscle movement failure 48with stimulation10 63 sciatic andfemoralpainleg trauma stump pain none failure 54Patientswere asked to characterize theirpain in termsof variouscharacteristicssuchas steady pulsating hot burning heavypressing aching. Patientsin either the partialsuccessor excellent category more oftencharacterized their pain as sharp and stabbing six patientsas compared to patientsinthe failure group one patient. Two patientsin the excellent result group had hypercsthesiasas major problem and thesedisappeared with stimulation. Power outputrequirementsfrom the transmitter did notincrease with time as has been noted withdorsal column stimulation5t although thefollow-up period is too short for thistoconclusive.Muscle cramping from stimulation did notoccur in any of the patientsin either of thesuccessgroups. Furthermore these patientsdid not find the stimulation distracting butrather that with the reduction in pain theyhad better ability to concentrate. Pain relieflastedfor variousbelengthsof time after givenstimulation period. In three patientsthe painbegan again as soon as stimulation stoppedin twootherspainreturned within 30 to 60minutesand in four otherspain returnedtohours.Patientsdenied that the stimulation interfercd with walking coordination sexualinfunctioning driving sensation or musculstrength. These patientsreported no tissuejuryresult.ofin the stimulated limbanalgesia.or elsewhereUniversity of Minnesota SeriesIn 1973 seriesof 10patientswithchrornerve injury treated with PNS implantsdescribed. At that time six patientsjudged to have excellent resultswhilehad good resultsand two were treatmefailures. Now yearslater one ofpatientsin the excellent result serieshas belost to follow-up while another has becomcfailure.Thislatter patient who hadtraumatic arm amputation continuedreceive stimulation into the painful areano longer obtainspain relief. The longefollow-up period is in two of the patientswiexcellentweresultswho have now been using.nar nerve stimulatorsfor yearsand cctinue to obtain complete pain relief. Theresultsarc summarized in Table 2.DiscussionThe best predictor for successin usingPNS implant in the treatment of intractabpain was the patientsdiagnosis. No patietreated with sciatic implant for the low ba696 J. Neurosurg. Volume 45 December 19sois

Nerve stimulation for intratctuble puzupain syndrome had an excellent result.Patientswith pain front ntetastatic diseasealso did poorly. Patientswith chronicperipheral nerve injury had the best results.withfoursix patientshaving excellenthaving partial success.resultsandhigh failure rate occurred in patientswith low back pain syndrome despitesuccessfultrialswithpercutaneoustion. The reason for thismay be relatedstimulato theobservation noted by the present authorsandothers12 that for stimulation to provide painrelief it must be applied to an area proximaltQ the source of the pain. Thusbipolarstimulation of the sciatic nerve in patientswith the low back pain syndrome would beexpectedto fail since the source of the pain isproximal to the area stimulated. The temporarythe other handtrialsstimulation may onsucceed since thisis done withunipolar stimulation which allowsfor greatercurrent spread. In support of thispreliminary work has shown that in suchpatientspercutaneousbipolar epiduralstimulationmay be completely effective inrelieving sciatic pain when the electrodesareplaced over the ipsilateral LA L-5 or S-Inerverootsunder fluoroscopic control.The first reported use of permanentperipheral nerve implantsfor pain controlwas made by Sweet and \Vepsc in 1968however these resultshave not beenpublished and detailed follow-up data are notavailable. Picaza et at reported that 20 outof 23 patientshad excellent resultsafterfollow-up period ranging from to 20months. Ninepatientsin their serieshadlowback pain syndrome. The stimulation wasapplied to an area remote from the locationof pain in nine patients. The reason for thediscrepancyour own is not clear.in resultsbetween their seriesandThe mechanism by which peripheral nervestimulationrelievesis still pain uncertain.Campbell and Taub confirmed that normalhuman subjectshad sensory lossduringtranscutaneousnerve stimulation in the distribution of the stimulated nerve. Thischangebegan with decreased touch sensation at lowlevelsof stimulation and progressed toanalgesia with levelshigherof stimulation.The development of analgesia was associatedwith lossof the A-delta elevation in the compound action potential recording whichsuggeststhat peripheral axonal blockadewas responsible for the observed analgesia.Thishypothesiswas supported by work ofTorehj rk and l-lallin2 who showed thatrepeated electrical stimulation of humanperipheralinnervesresulted in excitation failurefibersfollowed to lesser extent by excitation failure in fibers. That electricalstimulation may relieve clinical pain by thismechanism was shown by Wall and Gutnick.24Experimentally induced neuromasinratswere shown to have an abundance ofhyperirritable small myelinated fibersrecording techniquesdid not allow for recording from fibersthat showedprolongedsilentperiodsafter brief antidromic tetanus.mechanism by whichelectrical stimulationmay selectively block small fiber activity wasdescribed by Accornero at. who showedthat eathodal current can stimulate both largeandselectivelysmall fiberswhile the anodal currentaxonal blockadeinactivates the smaller fibers. Thehypothesisis in keeping withthe observation that electrical stimulationmust be applied to an area proximal to thesource of pain and to nerve of which theperipheral field of innervation includessite of origin of the pain.Alternatively peripheral nerve stimulationthemay inhibit pain perception by way of centralnervoussystem effects. There are numerousexamplesof inhibitory and facilitatory interactionsof sensory stimuli. It is postulatedthat electrical stimulation of peripheralnerve may block more distal nociceptive inputby inhibitory action at the dorsal horn brainstem thalamusor even the parietal cortex.The gate theory proposed by Melzackand Wall in 1965L0 representsspecifichypothesisinvolving thisgeneral mechanism.Thisproposal along with increasing Westernawarenessof the application of acupuncturein China led to the popularization of electrical stimulation techniquesfor the treatment of pain. In the gate theoryit isproposed that electrical stimulation activateslarge fiber activity in peripheral nerveswhichinducessuppression of transmission of largeand small fiber activity to high C145 structuresand thereby blockspain perception.The specific assumptionsof thishypothesishave not been supported by subsequent investigationsa.3.s.2.at and Wall himself hasstated The least and perhapsthe bestthatcan be said for the 1965 paper was that itprovoked discussion and experiment. Thet.ti1. Nvurocurg. Volunt- 45 December. /976 697301

J. N. Campbell and D. M. Longrote of central effects as meansby whichelectrical stimulation relievespain thereforeremainsunsettled.Conclusionsas to the role of peripheralnerve stimulation in the treatment of chronicpain can only be made tentatively. In selectgroupof patientsin thisseriesthismode oftreatment has provided relatively safeeffective meansof controlling pain. Thissuccessis evidenced by pain relief imin lifeprovementsstyle cessation of narcoticintake normalization of sleep-wake cyclesand improvement in psychological well-beingwith no disturbance of other neurologicalfunctions. The most promising group ofpatientsfor thismode of treatmentappearstobe those with peripheral nerve injurieswhich the stimulation can be attached to theaffected nerve at point proximal to the siteof injury. The incidence of complicationsappearsto be relatively low. The use of sciaticnerve stimulatorsin the treatment of the lowback pain syndrome and painfrom metastaticdisease is not advocated for in our seriesthesepatientshave done poorly. Futureresearch will be directed toward determiningthe safety of thistechnique and its mechanismof action and toward better definition ofthe patient population that will respondfavorably to its use.References1. Accornero Bini Manfredi Differential block of cutaneousnerve fiberswith triinangularly shaped electrical impulses. Presented at the First World Congressof theInternational Association for the Study ofPain Florence Italy September 19752. Bessou Perl ER Response of cutaneoussensory unitswith unmyelinated fibersto noxiousstimuli. Neurophysiol 321025104319693. Campbell 3M Local analgesia froni percutaneouselectrical stimulation andperipheral mechanism. M.D. thesisUniversity 1973Yale4. Campbell 3M. Taub Local analgesia fromelectrical stimulation.percutaneousperipheral mechanism. Arch Neurul 23347350 19735. Hodge Ci ir Potential changesinside centralafferentterminals secondary to stimulationoflarge- and small-diameter peripheral nervefibers. Neurophysiol 353043 19726. Long DM Electrical stimulation for rclicf ofpain from chronic nerve injury. Neurosurg3971S722 19737. Long DM External electrical stimulation astreatmcnt of chronic pain. Minn Med 57195198. 19748. Long DM Erickson DE Stimulation of theposteriorof1975intractablecolumnsof the spinal cord for reliefpain. Surg Neurol 41341419. Manfredi Modulation of sensory projectionsin anterolateral column of cat spinal cordby peripheral afferentsof different size. Archhal Biol 10872lOS1970 Eng10. Melzack Wall PD Pain mechanismsnew theory. Science 150971979 196511. Mendell Properties and distribution of.peripherally evoked presynaptic hyperpolarization in cat lumbar spinalcord. PhyslolLond 226769792 197212. Meyer GA FieldsIlL Causalgia treated byselectivelargenerve. Brain 95163168 1972fibre stimulation of peripheral13. Nashold BS Jr Friedman Dorsal columnstimulation for control of pain. Preliminaryreport on 30 patients. Neurosurg36590597 197214. Picaza JA Cannon BW Hunter SE ct alPain suppression by peripheral nerve stimulation. Part I. Observationswith implanteddevices. Surg Neurol 4115126 197515. Pineda Dorsal column stimulation and itsprospects. Surg Neurol 4157163 197516. Shealy CM Dorsal column stimulation optimization of application. Surg Neurol4142145 197517. Shealy CM Mortimer JT HagforsNR Dosal column clectroanalgesia. Neurosurg32560564 197018. Sweet WH Wepsic JO Stimulation of theposteriorcontrolcolumnsof the spinal cord for painindicationsClin Neurosurg 212783 10 1974techniquesand results.19. Sweet WH Wcpsic JO Treatment of chronicpain by stimulation of fibersof primaryafferent neurons. Trans Am Neurol Asset93103107 196820. Taub Electrical stimulation for the relief ofpain two lessonsin technological zealotry.Perspect Biol Med 19125135 Autumn 197521. Torebjork HE Hallin RO Responseshuman and fibersto repeatedinelectrical intradermal stimulation. Neurol NeurosurgPsychiatry 37653664 197422. Wngman III Price DD Respntsesof dorsalhorn celisof Af. mulatto to cutaneousand aural nerve and fiber stimuli. Neurophysiul32802817 196923. Wall PD Dorsal horn electrophysiology inIggo ed Handbook of Sensory PhysiologyVolume Soniatosensory System. BerlinSpringer-Vcrlag 1973 pp 253270698J.Peurosurg. Volume 43 0fjnbcr.1976

ItNerve stimulation or intractabic pattiWaIl PD Gutnick Ongoing activity inperipheralnervesthe physiology and phar.macology of impulsesoriginating from Adtlres.c eprin nqziesrs to Donlin NT. Longneuron. Exp Neurol 43580593 1974 M.D. Department of Neurosurgery Johns\ValI PD. Sweet %VH Temporary abolition of HopkinsHospital 601 North Broadway.pain in man. Science 155108109 1967 Baltimore Maryland 21205.illiiIVeurosurg. Volume 45 December. 197621El