Spinal Cord Stimulation - Podiatry Today

, LLCA supplement toSPECIAL SUPPLEMENT• Spinal Cord Stimulation for Treatment ofChronic Regional Pain Syndrome .......................3Julie Saranita, DO | Clermont, FL• Clinical Case Report No. 1: ................................7Residual Neuropathic Pain After Neuroma ExcisionTimothy Henne, DPM, FACFAS | Clermont, FL• Clinical Case Report No. 2: ...............................10Development of CRPS After Hammertoe SurgeryAnthony D. Saranita, DPM, FACFAS | Orlando, FL• Clinical Case Report No. 3: ...............................12Severe Neuropathic Pain Caused by Tarsal Tunnel SyndromeCannot be reprinted without permission of Podiatry Today and HMP CommunicationsDouglas Childs, DPM, FACFAS | Orlando, FLCopyright © 2010 by HMP Communications

• Spinal Cord Stimulation for Treatment of Chronic Regional Pain SyndromeJulie Saranita, DO 1 | Clermont, FL• Clinical Case Report No. 1:Residual Neuropathic Pain After Neuroma ExcisionTimothy Henne, DPM, FACFAS 2,3 | Clermont, FL• Clinical Case Report No. 2:Development of CRPS After Hammertoe SurgeryAnthony D. Saranita, DPM, FACFAS 3,4 | Orlando, FL• Clinical Case Report No. 3:Severe Neuropathic Pain Caused by Tarsal Tunnel SyndromeDouglas Childs, DPM, FACFAS 3,4 | Orlando, FLKeywords: Spinal cord stimulation, dorsal column stimulator, chronicregional pain syndrome, reflex sympathetic dystrophy, neuroma, stumpneuroma, tarsal tunnel syndrome, hammertoe surgery1Diplomate, American Board of Anesthesiology; board-certified in pain medicine;director of South Lake Pain Institute, Clermont, FL2Diplomate, American Board of Podiatric Surgery; Center for Ankle and FootCare, Clermont, FL3Board-certified in reconstructive rearfoot/ankle surgery4Diplomate, American Board of Podiatric Surgery; teaching faculty at FloridaHospital East Orlando Podiatric Surgical Residency Program; Orlando Footand Ankle Clinic, Orlando, FLCorresponding AuthorAnthony D. Saranita, DPM, FACFAS835 7th StreetClermont, FL 34711.E-mail: asaranita@yahoo.comCannot be reprinted without permission of Podiatry Today and HMP CommunicationsAcknowledgmentThe authors express appreciation toChristopher Reeves, DPM, FACFAS, for illustrations., LLC 2010-470-0052 Supplement to Podiatry Today • February 2010

Diagnosing and tr eating neur o-pathic pain can be v ery difficultfor healthcare providers, and evenmore fr ustrating for patients. Managementof neuropathic pain varies widely,and options include oral adjuv ant andtopical analgesics, opioids, physical therapy,and regional anesthesia.One of the most effective methods is aform of neur omodulation called spinalcord stimulation (SCS). SCS is a reversibleprocedure that is effecti ve in r educingpain and beneficial in restoring functionto the affected extr emities. This ar ticleprovides backg round on Chr onic RegionalPain Syndrome (CRPS) and itstreatments, and explores the benefits andpracticalities of using spinal cord stimulationto treat patients suffer ing from thistype of neuropathic pain.Causes of Neuropathic PainNeuropathic pain of any origin can bedebilitating to patients. Especially frustratingto patients is that neur opathicpain is one of the most difficult conditionsto treat, and may require repeat officevisits and extensi ve adjustments inmedications.Common causes of neur onal injurythat cause neur opathic pain includecomplex regional pain syndrome typesI and II, diabetic peripheral neuropathy,Spinal Cord StimulationSpinal Cord Stimulation for Treatment ofChronic Regional Pain SyndromeThe benefits of and keys to using an implantable spinal cord stimulatorto relieve neuropathic pain.phantom limb pain, postlaminectomysyndrome, compression and ner ve entrapmentsyndromes. However, neuropathicpain can also occur in theabsence of any injury or known cause.Neuropathic pain may result from a lesionin any part of the nervous system. 1It can involve uninjured adjacent neuronsleading to per ipheral sensitizationand increased excitability of the brainand spinal cord due to central sensitization.Typical manifestations of neuropathicpain include a burning sensation, throbbingpain accompanied b y allodynia(pain with light touch), h yperalgesia(exaggerated pain from pinprick), andsensory deficits. 2Complex RegionalPain Syndrome PrimerThe ter minology of CRPS , for merlyknown as Reflex Sympathetic Dystrophy(RSD), was revised in 1994 by the InternationalAssociation for the Study ofPain. 3 The following is a brief overview.CRPS Type I (RSD) includes the followingclinical findings: allodynia (suchas sensory changes), regional pain, temperatureabnor malities, edema, skincolor alterations, and abnor mal sudomotoractivity. CRPS Type II (causalgia)includes all of the above findings alongwith a definiti ve per ipheral ner ve lesion.It is also important to note that notevery criterion will be present in all patientswith CRPS.While the pathophysiology of the diseaseis not well understood, pain remainsessential to the diagnosis. Therefore, it isimportant to consider the possibility ofCRPS when treating a patient who haspain that is disproportionate to the incitingevent. CRPS usually occur s after aninciting e vent such as surger y or anepisode of trauma. It is important to notethat CRPS has been reported event aftertrivial events such as venipuncture. In fact,there ha ve been documented cases inwhich the patient may not even rememberthe event, because it seemed at thetime such a minor, everyday occurrence.Exclusion criteria for CRPS precludepatients with clinical findings that ar etemporarily proportionate anatomicallyand physiologically to an injury. 4Methods for ManagingNeuropathic PainRecognizing neuropathic pain is the firststep in tr eatment; attempting to medicallymanage the condition is often thesecond. Medications that have been usedto successfully treat neuropathic pain includethe adjuv ant analgesics. Thesemedications are referred to as adjuv antCannot be reprinted without permission of Podiatry Today and HMP CommunicationsSupplement to Podiatry Today • February 2010 3

Figure 1Figure 1. The implantable spinal cord stimulatormasks pain signals by delivering pulses of electricalcurrent directly to the spinal cord, therebytargeting pain in multiple areas.analgesic because their pr imary indicationis to tr eat conditions other thanpain, such as depression or epilepsy. Thesemedications include anti-epileptic drugs(such as gabapentin and pregabalin), tricyclicanti-depressants (such as amitriptylineand desipramine), and ne werserotonin-norepinephrine reuptake inhibitors(such as duloxetine, venlafaxine).Opioids such as tramadol are also believedto be effecti ve when used incombination with other medicationsand aggressive physical therapy. The useof opioids in neuropathic pain was initiallycontroversial, but is now recommendedas fir st-line tr eatment forneuropathic pain. 1,5Topical analgesics such as capsaicincream have been shown to be beneficialby depleting substance P fr om the peripheralter minals of sensor y ner vefibers. 4,6 Selective serotonin reuptake inhibitors,on the other hand, have beenshown to be no mor e effective in thetreatment of neur opathic pain thanplacebo in patients who ar e not clinicallydepressed. 7,8In addition to medical management,mobilization of the affected extremity isessential in the tr eatment. The role ofthe physical therapist should not be underestimatedwhen treating a CRPS patientbecause immobilization of theaffected extremity is counterproductive.Regional anesthesia as well as topicalanalgesics may be used in helping r e-store function to an effected extr emity.Sympathetic blocks are useful in identifyingpain that is sympathetically mediated.The procedure is perfor med byplacing the tip of the needle under fluoroscopicguidance anter ior to the L2or L3 vertebral bodies. A local anestheticis injected to interrupt the transmissionof the lumbar sympathetic ner ves. Objectivedeter mination of a successfulblock includes findings of v asodilationand incr eased temperatur e in the effectedextremity.If a patient r eports reduced pain afterthe procedure, then the pain is classifiedas being sympathetically mediated. Sympatheticblocks performed before physicaltherapy may aid in f acilitating mobilizationof the effected extremity and greaterparticipation in physical therapy. A seriesof lumbar sympathetic blocks are continueduntil either the patient receives resolutionof their pain or no longerdemonstrates continued benefit.History ofSpinal Cord StimulationNeuromodulation is a scientificallyproven treatment used to alter the electricalsignals sent to the brain and spinalcord. SCS, a form of neuromodulation,masks the pain signals b y deli veringpulses of electr ical current directly tothe spinal cord, thereby targeting painin multiple areas (see Figure 1).The use of SCS w as first reported byShealy in 1967. 9 Since then, the devicehas been used to treat a variety of painfulconditions. SCS has been widely appliedto a variety of neuropathic pain conditionsover the past 30 years. Clinical studiesshow it is a safe , effective therapeuticmodality for reducing chronic refractorypain of the trunk and limbs. 10The spinal cord stimulator itself is animplantable medical de vice that bothgenerates and transmits an electrical impulse,thus cr eating an electr ical fieldthat stimulates the dorsal column fibersin the spinal cor d. These electrical impulsesconvert pain signals into par esthesias,which ar e per ceived b y thepatient as a tingling, pleasant sensation.The potential advantages of SCS includethe reduction or elimination ofmedication use in addr essing patients’pain. In addition, SCS is a r eversibleprocedure that is effecti ve in not onlyproviding anaglesia b ut also r estoringfunction to the affected extremities. 4Cannot be reprinted without permission of Podiatry Today and HMP CommunicationsPhoto courtesy Boston ScientificSCS Mechanism of ActionA variety of theor ies have been postulatedas to the mechanism of action ofspinal cord stimulation. In the gate-controltheory, first published by Melzack4 Supplement to Podiatry Today • February 2010

Spinal Cord Stimulationand Wall in 1965, 11 the authors postulatedthe existence of a pr overbial gatein the dor sal hor n of the spinal cor d.This so-called gate contr ols the transmissionof neural activity. 12 By stimulatingthe dor sal hor n and ther ebyactivating the large diameter affer entnerve fibers, the gate could be closed,resulting in suppression of painful inputsto the central nervous system. 12While the exact mechanism of SCSis still debated, recent studies have suggestedthat the effects of SCS are mediatedby multiple mechanisms and ar eeffective in neuropathic, sympatheticallymediated pain and ischemic painstates. 12 SCS is thought to affect theneurotransmitters in the central nervoussystem, acti vate supraspinal cir cuits,modulate the spinothalamic tracts, suppressionof sympathetic activity and activationof the descending inhibitor ypain pathways. 13Indications for Use of SCSSCS is indicated for pain in the tr unkand limbs. It has been shown to be effectivein painful conditions such as radicularpain syndromes, failed back surger ysyndromes, and CRPS. 14 In addition toneuropathic chronic pain conditions inthe trunk and limbs, other applicationsfor SCS ha ve been cited in the literature.14-16Figure 2Figure 2. A screening trial lets the patient test drive the spinal cord stimulator device before permanentdevice implantation. During the trial, the leads are taped to the skin and connected to an externalbattery via an extension cable.Surgical TechniqueA screening trial that lets the patient testdrive the spinal cord stimulator device isperformed before permanent implantationof the device. The trial can be donein the office under light intravenous sedationand local anesthesia while the painmedicine physician percutaneously insertsthe leads. The trial leads are removedafter the tr ial period regardless of theiroutcome. This lets the treating physicianand patient adequately assess the benefitderived from the trial before proceedingto surgical implantation. Hence, removingthe per cutaneous leads mak es thetrial a reversible procedure and helps addresspatients’ pre-operative concerns.The patient is placed in a prone position.A 14-gauge epidural needle is typicallyinser ted into the upper lumbarepidural space. The spinal cord stimulatorleads are then inserted through theneedle and advanced cephalad into thethoracic epidural space under fluor o-scopic guidance. For the lower extremity,the lead tip is typically placedbetween T10 and T11. For bilateral legpain, two leads ar e typically inser ted.Each lead has eight contacts.During the trial, the leads are taped tothe skin and connected to an exter nalbattery via an extension cab le (see Figure2). The goal is to overlap the paresthesiasproduced by the device with thepatient’s painful areas. The device representativeuses an external programmer toadjust the voltage, pulse width and fr e-quency (see Figures 3 and 4). The patientis given several programs to choosefrom, the tr ial phase typically lasts between3 and 7 da ys, which lets the patientassess the effecti veness of thestimulation under normal circumstancesand in nor mal surroundings. 13 The patientis able to turn on and off the deviceusing a wir eless remote control. Uponcompletion of the tr ial, the patient r e-turns to the physician’s office to have theleads removed.A tr ial is consider ed successful if aCannot be reprinted without permission of Podiatry Today and HMP CommunicationsPhoto courtesy Boston ScientificSupplement to Podiatry Today • February 2010 5

Figure 3Figure 4Figures 3 and 4. Once the trial device has beenattached, the device representative uses an externalprogrammer to adjust the voltage, pulse widthand frequency. The patient is able to access severalprograms over the 3- to 7-day trial phase.Figure 5Figure 5. During surgical implantation, a subcutaneouspocket is created in the gluteal area forthe impulse generator (battery). The leads arethen tunneled to the pocket and connected tothis rechargeable battery.Photo courtesy Boston Scientific Photo courtesy Boston ScientificPhoto courtesy Boston Scientific6 Supplement to Podiatry Today • February 201050% reduction in the intensity of thepain is achieved. If the trial is successful,the patient is then scheduled for implantationof the device in an operatingroom as an outpatient pr ocedure. Implantationof the SCS can be performedeither percutaneously or open. Opensurgical placement involves the use of apaddle lead placed thr ough an openlaminotomy incision.For permanent lead placement, a skinincision is made at the lead inser tionsite. Once the leads ar e placed in theepidural space, they are anchored to thefascia or supraspinous ligament. A subcutaneouspock et is cr eated in thegluteal area for the impulse generator ,or battery. The leads are then tunneledto the pock et and connected to thisrechargeable battery (see Figure 5).SummarySpinal cord stimulation has a high initialacquisition cost, but reductions in medicationusage, physician visits, emergencyroom visits, absence from work, surgeries,and additional hospitalizations offset overallcosts. 13,17 Many studies ha ve shownspinal cord stimulation is cost-effective intreating pain in comparison to other conservativetherapies; Bell et al sho w SCSpays for itself within 2.1 years. 17,18In the follo wing pages, we explorethree real clinical cases in which SCSwas used to treat different CRPS situations:after neuroma surgery (see p. 7);after hammertoe surgery (see p. 10); andafter failed tarsal tunnel (see p. 12). ■References1. Raja SN, Haythornthwaite JA. Combinationtherapy for neuropathic pain — whichdrugs, which combination, which patients?N Engl J Med. 2005;352(13):1373–1375.2. Yearwood T. Neuropathic extremity pain andspinal cord stimulation. Pain Med.2006;7(S1): S97–S102.3. Merskey H, Bogduk N. Classifications ofChronic Pain: Descriptions of ChronicPain Syndromes and Definitions of PainTerms. 2nd ed. Seattle, WA: IASP Press;1994:209–214.4. Stanton-Hicks M, Baron R, Boas R, et al.Complex regional pain syndromes: guidelinesfor therapy. Clin J Pain. 1998;14(2):155–166. Review.5. Ballantyne JC, Mao J. Opioid therapy forchronic pain. N Engl J Med. 2003;349(20):1943–53.6. Sawynok J. Topical analgesics in neuropathicpain. Curr Pharm Des. 2005;11(23):2995–3004.7. Max MB, Lynch SA, Muir J, et al. Effects ofdesipramine, amitriptyline and fluoxetineon pain in diabetic neuropathy. N Engl JMed. 1992; 326(19):1250–1260.8. Lynch ME. Antidepressants as analgesics: A reviewof randomized controlled trials. J PsychiatryNeurosci. 2001;26(1):30–36.9. Shealy CN, Mortimer TJ, Reswick JB. Electricalinhibition of pain by stimulation of thedorsal columns: preliminary clinical report.Anesth Analg. 1967;46(4):489–491.10. Cameron T. Safety and efficacy of spinal cordstimulation for the treatment of chronicpain: a 20-year literature review. J Neurosurg.2004;100(3 Suppl Spine):254–267.11. Melzack R, Wall PD. Pain mechanism: a newtheory. Science. 1965;150(699):971–999.12. Oakley JC, Prager JP. Spinal cord stimulation.Spine. 2002;27(22):2574–2583.13. Stojanovic MP, Abdi S. Spinal Cord Stimulation.Pain Physician. 2002;5(2):156–166.14. Lee AW, Pilitsis JG. Spinal cord stimulaton:Indications and outcomes. Neurosurg Focus.2006;21(6):E3.15. Deer TM, Masone RJ. Selection of spinal cordstimulation candidates for the treatment ofchronic pain. Pain Med. 2008;9(S1):S83–S92.16. Linderoth B, Foreman RD. Physiology ofspinal cord stimulation: Review and update.Neuromodulation. 1999;2(3):150–16417. Taylor RS, Taylor RJ, Van Buyten J-P, et al.The cost effectiveness of spinal cord stimulationin the treatment of Pain: a systematicreview of the literature. J Pain SymptomManage. 2004;27(4):370–378.18. Bell GK, Kidd D, North RB. Cost effectivenessanalysis of spinal cord stimulation intreatment of failed back surgery syndrome. JPain Symptom Manage. 1997;13(5):286–295.Cannot be reprinted without permission of Podiatry Today and HMP Communications

Morton’s inter metatarsal neuromais a compr ession neuropathythat most commonlyinvolves the dig ital nerves. The patienthistory, clinical findings and tr eatmentguidelines have recently been publishedand are based on a consensus of currentclinical practice and a r eview of theclinical literature. The guidelines weredeveloped b y the Clinical PracticeGuideline Forefoot Disorders Panel ofthe American College of F oot andAnkle Surgeons. 1Neuromas ar e most commonlyfound in the 3r d interspace, but canoccasionally occur in the other spacesas well. The patient histor y will typicallydescr ibe a b urning or tinglingsensation and possible numbness thatinvolves the associated dig its. The patientmay describe a “hot pok er” or“wrinkle in the sock” sensation that isexacerbated in shoe gear and with ambulation.Relief is often felt upon r e-moval of the shoe and with massage ofthe area.The clinician will commonly be ableto elicit pain and a palpable click (Mulder’ssign) with manipulation of the interspace.X-ra ys ar e needed on theinitial visit to exclude any bony pathologyand MRI may be considered to aidResidual Neuropathic PainClinical Case Report No. 1: ResidualNeuropathic Pain After Neuroma ExcisionA patient who was successfully treated by spinal cord stimulationfor a recurrent neuroma and residual neuropathic pain after previoussurgical resectionin the diagnosis. Devices such as ultrasoundand pr essure-specified sensor ydevice (PSSD) can be v ery helpful ifavailable to the clinician.The diagnosis is made clinically; otherancillary tests should be r eserved foratypical pr esentations or to excludeother types of patholo gy. Pathologicalconditions that mimic Mor ton’s neuromainclude stress fracture, metatarsalphalangeal joint bursitis, metatarsal phalangealjoint instability or predislocationsyndrome (PDS), neoplasm, metabolicperipheral neuropathy, or other chronicpain syndromes.Initial treatment consists of the use ofwider shoes, metatarsal padding, anti-inflammatorymedications and injectionsof either steroids or 4% alcohol. If thepain does not r esolve, the most commonsurgical procedure is excision ofthe neuroma (see Figures 1 and 2 ).Decompression surgery and cr yogenicneuroablation are becoming more commonin attempts to decr ease the complicationsassociated with resection suchas, stump neuroma, seroma, wound dehiscenceand infection.Recurrent or stump neuroma can bea challenging entity for the clinician. Ithas a recurrence rate of 3% to 24% afterdorsal excision, 2–12 and patients whohave failed a primary nerve resection areoften hesitant to undergo fur ther surgery.The symptoms of r ecurrent neuromacan often o verlap with m ultipleetiologies including or thopedic andneuropathic pain conditions.Attempts ha ve been made to decreasethe incidence of r ecurrencewith conservative and surg ical techniques.More conservative treatmentsinclude injections (steroids or 4% alcohol),massage, ultrasound, orthotics,NSAIDS, and adjuv ant analgesics.During initial surger y, the se verednerve is relocated into a local m usclebelly dur ing the initial surger y. Thismay aid in preventing localized traumato the ner ve, but there has been noproven tr eatment to pr event “r e-growth” of the ner ve. 13 Additionalsurgical treatment is commonly performedvia plantar excision with furtherr esection and m uscularimplantation with the possible need ofan additional tarsal tunnel release. 13Pain and n umbness to the plantarfoot, under or betw een the metatar salheads is the pr imary complaint. Accurateclinical diagnosis is paramount tosuccessful treatment; consultation witha pain management ph ysician may aidin accurate diagnosis and tr eatment. IfCannot be reprinted without permission of Podiatry Today and HMP CommunicationsSupplement to Podiatry Today • February 2010 7

Figure 1Figure 2Figures 1 and 2. If the pain caused by a Morton’s intermetatarsal neuroma does not resolve with medicalmanagement, the neuroma can be surgically excised.there is any doubt that the pain is neurologicallyinduced, one can consider anMRI for evaluation of a str ess fractureor bursitis to the associated structures.The neur oma is often located inclose proximity to either the 3r d or4th metatar sal head. PDS m ust beruled out. Occasionally, a patient willpresent with PDS after nerve resectionor due to possible misdiagnosis of PDSbefore the initial nerve resection. Palpationin the ar ea will elicit pain inboth recurrent neuroma and PDS, butthe clinical histor y is quite differ ent,thus the clinical histor y is essential inmaking the diagnosis.Neuroma and r ecurrent neur omapain ar e significantly r educed whenthe patient is bar efoot or wears wideshoes, wher eas PDS is often mostpainful when barefoot. A simple clinicaltest is to strap the toe in a slightlyflexed position with a cross-tape or bybuddy splinting the associated toes.Recurrent neuroma diagnosis can beaided by use of a PSSD. 13 Other neurologicalproblems that may complicatethe diagnosis of r ecurrentneuroma are diabetic per ipheral neuropathy,idiopathic per ipheral neuropathy,tar sal tunnel syndr ome,and radiculopathy.The following case reports a patientwho was successfully treated by spinalcord stimulation for a r ecurrent neuromaand residual neuropathic pain afterprevious surgical resection.Patient and CaseA 31-year old w oman presented tothe office 9 months after nerve resectionfor 2nd and 3r d interspace neuromas,originally performed by her orthopedicsurgeon. Her pain was improved for thefirst 2 months. However, she had a r e-currence of pain that w orsened 3months after the surgery.The patient tr ied physical therapyand a TENS unit, both of which failedCannot be reprinted without permission of Podiatry Today and HMP Communications8 Supplement to Podiatry Today • February 2010

Residual Neuropathic PainFigure 3Figure 3. A 31-year-old woman who could not gain pain relief from more conservative treatments —such as orthotics and anti-neuropathic medications — for neuropathic pain after neuroma excision underwentpermanent implantation of a spinal cord stimulator. After 8 months, she was able to discontinueall pain medications.to impr ove her pain. She w as thenstarted on a combination of anti-neuropathicmedications — gabapentinand nortriptyline — without relief. Aseries of local ster oid injections andperipheral nerve blocks provided onlytemporary relief.Initial pr esentation w as for “footpain after surger y.” The patient’s historyalso revealed lower back pain. Localizedtenderness plantar and slightlylateral to the 3r d metatarsal head wasobserved with “shooting pain” proximally.X-ray findings were negative forosseous pathology.A tentative diagnosisof recurrent neuroma was made andthe patient was instructed to use pregabalin75 mg PO qhs for 3 days thenBID on day 4. Over-the-counter orthoticswere customized to offload thearea, and she was given a prescriptionfor an MRI. She was then instr uctedto follow up in 2 weeks.The patient denied an y relief withorthotics or with pr egabalin. Her MRIwas negative for stress fracture or bursitis,but showed inflammation to the plantarfoot between the metatar sal heads. Thepatient refused any further invasive proceduresand was referred to a pain managementphysician for further care.The patient was then initiated on duloxetine,hydrocodone and diclofenac,all of which failed to improve her symptoms.A lumbar sympathetic b lock alsofailed to alleviate her symptoms. Afterfailing conservative treatment and continuingto suffer fr om lower extremitypain, the patient agreed to a 5-day spinalcord stimulator trial using the PrecisionPlus TM (Boston Scientific Cor poration,Valencia, CA).During the trial, the patient reportedgreater than 80% reduction in her pain.She underwent permanent implantationof the spinal cord stimulator (see Figure3). At the 8-month follo w-up, the patienthas been ab le to discontin ue allpain medications. For exercise, she haseven returned to her pr ior routine oflong-distance running. ■References:1. Thomas JL, Blitch EL, Chaney M, ClinicalPractice Guideline Forefoot DisordersPanel, et al. Diagnosis and treatment offorefoot disorders. Section 3. Morton's intermetatarsalneuroma. J Foot Ankle Surg.2009;48(2):251–256.2. Bradley N, Miller WA, Evans JP. Plantar neuroma:analysis of results following surgicalexcision in 145 patients. South Med J.1976;69(7):853–854.3. Gauthier G. Thomas Morton's disease: a nerveentrapment syndrome. A new surgicaltechnique. Clin Orthop Relat Res.1979;(142):90–92.4. Mann RA, Reynolds JC. Interdigital neuroma— a critical clinical analysis. Foot Ankle.1983;3(4):238–243.5. Addante JB, Peicott PS, Wong KY, Brooks DL.Interdigital neuromas. Results of surgicalexcision of 152 neuromas. J Am PodiatrMed Assoc. 1986;76(9):493–495.6. Karges DE. Plantar excision of primary interdigitalneuromas. Foot Ankle.1988;9(3):120–124.7. Gudas CJ, Mattana GM. Retrospective analysisof intermetatarsal neuroma excisionwith preservation of the transversemetatarsal ligament. J Foot Surg.1986;25(6):459–463.8. Gaynor R, Hake D, Spinner SM, TomczakRL. A comparative analysis of conservativeversus surgical treatment of Morton's neuroma.J Am Podiatr Med Assoc.1989;79(1):27–30.9. Keh RA, Ballew KK, Higgins KR, Odom R,Harkless LB. Long-term follow-up ofMorton's neuroma. J Foot Surg.1992;31(1):93–95.10. Friscia DA, Strom DE, Parr JW, SaltzmanCL, Johnson KA. Surgical treatment forprimary interdigital neuroma. Orthopedics.1991;14(6):669–672.11. Ruuskanen MM, Niinimäki T, Jalovaara P.Results of the surgical treatment of Morton'sneuralgia in 58 operated intermetatarsalspaces followed over 6 (2-12)years. Arch Orthop Trauma Surg.1994;113(2):78–80.12. Banks AS, Vito GR, Giorgini TL. Recurrentintermetatarsal neuroma. A follow-upstudy. J Am Podiatr Med Assoc.1996;86(7):299–306.13. Wolfort SF, Dellon AL. Treatment of recurrentneuroma of the interdigital nerve byimplantation of the proximal nerve intomuscle in the arch of the foot. J Foot AnkleSurg. 2001;40(6):404–410.Cannot be reprinted without permission of Podiatry Today and HMP CommunicationsSupplement to Podiatry Today • February 2010 9

Clinical Case Report No. 2: Development ofCRPS After Hammertoe SurgeryA patient who was successfully treated with spinal cord stimulation for neuropathicpain resulting from a second hammertoeFigure 1Figure 2Figures 1 and 2. Many surgical options are nowavailable for hammertoe, including digital arthroplasty,digital arthrodesis, tendon transfers, andtendon lengthening.Hammertoe correction is a part ofevery surg ical practice . Thesedigital contractures can occur inall three planes of motion including thefrontal, sagittal, and transverse planes. 1Initial classifications of the digital deformitieswe often encounter will includeclaw toe, mallet toe, curly toe, and theclassic hammertoe. The specific term tobe used depends on the location of hyperextensionand hyperflexion. With theclassical hammertoe deformity, 2 we seehyperextension at the metatar sal phalangealjoint as w ell as at the distal interphalangealjoint and an associatedhyperflexion at the pr oximal interphalangealjoint.The etiology of the defor mity includesintr insic m usculature imbalance,length ir regularities of therespective lesser metatar sals, an elongatedplantar plate , progressive contracturesecondary to an ar thropathyand the list goes on fr om there. Froma biomechanical standpoint, we oftenrefer to the causes of hammer toes tobe flexor stabilization, 3 extensor substitution,4,5 or flexor substitution. 1 Regardlessof the etiolo gy, when dig italdeformities lead to pain or tissuebreakdown, they must be addressed.Treatment generally f alls into tw ocategories: conservative care and surgicalinter vention. Conser vative options,especially with a r igid dig italcontracture, ar e often limited topadding and shoe modifications. Whiledifferent manufacturers have producedmore varieties of pads then most of uswill ever use, their goal is often thesame: alleviating pressure from the areaof ir ritation. A biomechanical argumentfor orthotics can always be madewhen addr essing conser vative tr eatmentof hammer toes. If conser vativemeasures fail to adequately address theproblem and the patient is a surg icalcandidate, then surgical intervention isa viable option.Many surgical options are now available(see Figures 1 and 2 ). Surgicaloptions include dig ital ar throplasty,digital ar throdesis, tendon transfer s,tendon lengthening, flexor tenotomies,capsular r ebalancing, capsulotomies,plantar plate procedures, and implantarthroplasties, as well as various combinationsof those procedures.As with any surgery, there is a chanceof complications — hammertoe surgeryis no exception. Surgical complicationsof hammertoe surgery were well outlinedby Judge. 6 Neuritis was discussedamong them; however, Complex RegionalPain Syndrome (CRPS) was not,because it is not generally considered tobe a complication specific to or commonwith digital surgery.The following case reports on a patientwho was successfully treated withspinal cord stimulation for neuropathicpain (due to CRPS) r esulting from asecond hammertoe surgery.Patient and CaseA 39-year old female presented to the clinicianwith a painful second hammertoe.Initial conser vative measur es includedpadding, digital splints and shoe modifications.Unfortunately, the patient f ailedto respond favorably to conservative careCannot be reprinted without permission of Podiatry Today and HMP Communications10 Supplement to Podiatry Today • February 2010

CRPS After Hammertoe SurgeryFigure 3Figure 3. After implantation of the permanent spinal cord stimulator with a single lead at T-10, the patientno longer needs any medications to address her pain.and progressed on to surgery.The isolated digital surgery went welland the patient initially appeared to berecovering in an une ventful manner .Unfortunately, approximately 3 weekspost-operatively, the patient called r e-questing “more” and “str onger” painmedications. Given the abr upt changein the patient’s desire for additional opioids,she w as instr ucted to r eturn toclinic where she could be re-evaluated.The initial clinician concer n was forthe potential for abuse of the prescriptionpain medication. What was insteaddiscovered upon her arrival was an evenworse case scenario: The previously ambulatorypatient presented to the clinicon crutches. During the evaluation, thepatient was noted to be guar ding thefoot. She was also noted to have edemato the second digit as well as the entireforefoot. Examination revealed a temperaturedifference between the affectedand the contra-lateral lower extremity.She was educated on concer ns relatedto neuropathic pain and the probabilityof CRPS . Initial medicalmanagement included additional opioidsand an escalating dose of pr egabalin.After an extended discussion withthe patient, she revealed that she previouslysuffered from “something similar”when she had injur ed her upperextremity, but related that the physicianhad called it “something differ ent” atthe time. When the term reflex sympatheticdystr ophy (RSD) w as mentioned,she immediately related that tobe the condition for which she hadbeen treated after what tur ned out tobe a lower-trunk brachial plexopathy.Given the prior history of CRPS, thispatient was immediately r eferred to apain medicine practitioner for fur thertreatment. The patient was initiated onpregablin and dulo xetine by the painmanagement physician. Three separatelumbar sympathetic nerve blocks whereperformed. Each block was performedone day before physical therapy to facilitatepatient participation.The patient initially r eported a 60%reduction in pain following the sympatheticnerve blocks, but the favorable resultswher e not sustained for an ysignificant duration. The sympatheticnerve blocks where discontinued becausethe last pr ocedure failed to provideeven temporary reduction in herpain. Additional medical managementincluded oxycodone, methadone, hydrocodone,and clonazepam, all withoutbenefit to this patient.The patient then underw ent a 7-dayspinal cord stimulator trial, using PrecisionPlus TM (Boston Scientific Corporation,Valencia, CA). The patient reporteda 90% reduction in her foot pain dur ingthe trial and subsequently pr ogressed toimplantation of a per manent spinal cordstimulator (see Figure 3) with a singlelead at T-10. She has since returned to allactivities and no longer needs an y medicationsto address her pain. At 10-monthfollow-up, the patient continues to maintainreduction in pain and remains a productive,working member of society. ■References1. Root W, Weed J, Orien S. Normal and abnormalfunction of the foot. Vol. 2. Los Angeles,CA: Clinical Biomechanics Corp.;1977:302–309.2. Schuster, OF. Foot Orthopedics. New York,NY: Marbridge; 1927:293–297.3. Gray ER. The role of leg muscles in variationsof the arches in normal and flat feet. PhysTher. 1969;49(10):1084–1088.4. Green DR, Ruch JA, McGlamry ED. Correctionof equinus-related forefoot deformities:a case report. J Am Podiatry Assoc.1976;66(10):768–780.5. Whitney AK, Green DR. Pseudoequinus. JAm Podiatry Assoc. 1982;72(7):365–371.6. Judge, M. How to address complications ofhammertoe surgery. Podiatry Today.2007;20(6):62–70.Cannot be reprinted without permission of Podiatry Today and HMP CommunicationsSupplement to Podiatry Today • February 2010 11

Clinical Case Report No. 3:Severe Neuropathic Pain Caused byTarsal Tunnel SyndromeA patient who was successfully treated by spinal cord stimulation aftertarsal tunnel decompression failed.Tarsal tunnel syndr ome refers tocompression of the posterior tibialnerve as it cour ses along theposterior-medial aspect of the ankle andinto the foot. Keck and Lam w ere thefirst to describe the condition in 1962. 1,2The classic symptoms include paresthesiasalong the medial aspect of the heelassociated with a burning sensation intothe ankle. Pain is often agg ravated byprolonged standing or walking and frequentlyincludes pain at night. Uponexamination, the clinician can elicit apositive Tinel’s sign with percussion ofthe tibial ner ve. In rare cases, a spaceoccupyinglesion may even be palpated.Accurate diagnosis of tarsal tunnel syndromecan be challenging. Many conditionsmimic findings of tar sal tunnelsyndrome. Examples of these conditionsinclude lumbosacral radiculopath y andperipheral neuropathy. Although controversial,electrodiagnostic studies are stillthe most common objective test used forevaluation. The use of a pr essure-specifiedsensory device (PSSD) has becomean alternative method of nerve conductiontesting. 3 An MRI should be orderedbefore treatment to evaluate for a spaceoccupying lesion as w ell as to excludeentities such as intrafascicular ganglions 4and neurilemmomas, 5 which may mimictarsal tunnel symptoms.Tarsal tunnel syndrome may be theresult of both intrinsic and extrinsic factors.Intr insic f actors include o verpronationresulting in a traction injur yor direct compression within the flexorretinaculum. Extr insic f actors includelumbosacral radiculopathy, diabetic neuropathy,ganglions, varicosities, and otherspace-occupying lesions.Conservative care should al ways beattempted when possible. This may includeorthotics, injections, anti-inflammatorymedications, and ph ysicaltherapy. Ob vious exceptions to pr o-longed conservative measures would includemalignancy or a largespace-occupying lesion causing dir ectnerve compression, as expedient surgicalintervention would be indicated.Surgical decompression (see Figures1 and 2) is associated with a high rate ofcomplications. Gundring reported that100% of patients de veloped positi veTinel’s signs and abnormal nerve studiesafter surgery. 6 Raikin also noted that revisionaltar sal tunnel surger y rar elyyielded additional benefit to the patient. 7Chronic tarsal tunnel pain that fails torespond to conser vative tr eatment orsurgical intervention poses a significantobstacle to both the patient and ph ysician.Extrinsic factors such as diabeticneuropathy or lumbosacral conditionscan be of such severity that a tarsal tunneldecompression provides only minimalbenefit to the patient — and ma yeven cr eate an exacerbation of theirpain. In these cases, a timely referral toan interventional pain management specialistfor spinal cord stimulation mightbe indicated.The following case reports a patientwho was successfully treated by spinalcord stimulation to alleviate neuropathicpain when surgery for tarsal tunnel syndromefailed.Patient and CaseA 57-year-old female with multiple comorbidities,including diabetes mellitus,obesity and fibromyalgia, presented tothe office with severe pain in both feet.She was initially treated by her primarycare physician for diabetic neur opathyand b y another podiatr ist, who performedcor tisone injections, initiatedphysical therapy, and provided biomechanicalsupport.Despite this care, she denied any improvementin her intensity of heel painCannot be reprinted without permission of Podiatry Today and HMP Communications12 Supplement to Podiatry Today • February 2010

Figure 3Figure 3. Two weeks after the trial, the patient underwent implantation of the device with dual spinal cord stimulator leads. Two years later, she continues touse the spinal cord stimulator and has been able to discontinue the majority of the pain medications.Her left foot VAS was originally reportedas 10/10, now a 2/10. The right foot alsoimproved from the original 8/10 to 2/10.Her neuropathic and fibromyalgia painremained under the care of her pr imarycare physician.She was referred to physical therapyfor her loss of balance and underw entgait therapy and anodyne tr eatments.Several weeks into this therapy she presentedwith burns on her right foot andankle from the anodyne machine . Shewas treated with local wound care, andthe wounds healed.The patient subsequently missed severalof her scheduled appointments forpersonal reasons and after a 3-monthgap, presented with severe foot pain. Shedenied benefit with anodyne therap yand related an exponential incr ease inthe intensity of her pain to both feetafter the burn from the therapy. Clinicalpresentation included bilateral edema,an antalgic gait and loss of balance.Upon lower-extremity physical examination,the patient was noted to demonstratepain with light touch to bothheels. She also demonstrated limitedankle joint range of motion due to theswelling of her legs. A venous Dopplerwas ordered and did not demonstrate thepresence of a deep venous thrombosis toeither lower extremity.NSAIDs and opioids were prescribedand adjustments were made to her anxiolyticmedications. Despite this tr eatment,she returned with severe burningand tingling in both feet. Her pain wasreported to be worse at night, limitingCannot be reprinted without permission of Podiatry Today and HMP Communications14 Supplement to Podiatry Today • February 2010

Failed Tarsal Tunnel Surgeryher ability to sleep for any duration.Clinical examination w as noted todemonstrate allodynia and hyperalgesiato the bilateral heels with muscle weaknessand peripheral edema. A strong suspicionof chr onic r egional painsyndrome (CRPS) w as documented,and the patient was referred to an interventionalpain medicine ph ysician.Upon examination of the patient, thediagnosis of CRPS was confirmed. Thepatient failed medical management andultimately went on to r eceive a spinalcord stimulator.The patient was initiated on baclofento addr ess lo wer-extremity m usclespasms and celeco xib to addr ess painsecondary to osteoar thritis. Additionalmedical management also included thefollowing anti-neuropathic medications:duloxetine, venlafaxine, gabapentin, andpregabalin, which all f ailed to alleviateher pain. Opioids where discontinueddue to intolerable side effects.After failing conservative treatment,the patient underw ent a 5-da y spinalcord stimulator tr ial. Dur ing the tr ialthe patient was able to ambulate withoutdifficulty. She also r eported improvedsleep and a 95% reduction in theintensity of her pain. Two weeks afterthe trial, the patient underwent implantationof the de vice with dual spinalcord stimulator leads (see Figure 3).The patient continues to use her spinalcord stimulator 2 years after implantationand has been ab le to discontinue use ofthe majority of the pain medications. Asdemonstrated in the patient described inthis case r eport, implantab le SCS canprovide a safe modality for the treatmentof chronic pain in the lo wer extremity,and may be an option that is under usedby the podiatric profession. ■References1. Keck C: The tarsal tunnel syndrome. J BoneJoint Surg Am. J Bone Joint Surg Am.1962;44-A:180–182.2. LAM SJ. A tarsal-tunnel syndrome. Lancet.1962;2(7270):1354–1355.3. Tassler PL, Dellon AL. Pressure perception inthe normal lower extremity and in thetarsal tunnel syndrome. Muscle Nerve.1996;19(3):285–289.4. Fujita I, Matsumoto K, Minami T, et al. Tarsaltunnel syndrome caused by epineural ganglionof the posterior tibial nerve: reportof 2 cases and review of the literature. JFoot Ankle Surg. 2004;43(3):185–190. Review.5. Marui T, Yamamoto T, Akisue T, et al.Neurilemmoma in the foot as a cause ofheel pain: a report of two cases. Foot AnkleInt. 2004;25(2):107–111.6. Gondring WH, Shields B, Wenger S. An outcomesanalysis of surgical treatment oftarsal tunnel syndrome. Foot Ankle Int.2003;24(7):545–550.7. Raikin SM, Minnich JM. Failed tarsal tunnelsyndrome surgery. Foot Ankle Clin.2003;8(1):159–174.Cannot be reprinted without permission of Podiatry Today and HMP CommunicationsSupplement to Podiatry Today • February 2010 15

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