 \231 Fluoroscopic guidance (i.e. X-ray image intensifi er or a C-arm X-ray system with in jection of radiopaque contrast to confi rm needle tip position) for epidural steroid inject ions and other IPM techniques enhances accuracy of locating the target tissue and reduces t he potential injury to the surrounding structures. Safe and effi cient use of these modalit ies requires formal train- ing, skills and experience, with attention to minimizing radia- tion exposure to patients \200\231 vital organs and clinicians (Eckel and Bartynski, 2009 ; Hodge, 2005 ). \231 Ultrasound imaging allows visualization of soft tissue, bony, vas- cular, and neural structures, and can diff erentiate various tissue planes and spaces (e.g. epidural, intrat hecal, pleural and perito- neal). Th e operator can confi rm desirable spread of the inject ate in real time. Ultrasound imaging avoids radiation and is virtually without side eff ect s (Peng and Narouze, 2009 ). Interventional pain management for CRPS Sympathetic ganglion blockade Sympathetic ganglia b lockade with local anesthetics may be used as a diagnostic test, and a positive response is interpreted as sym- pathetically mediated pain (SMP), however, this view is not shared by all researchers and is not supported by rigorous investigation. Although favorable response s to sympathetic blockade has been used to predict pain relief from implanted spinal cord s timulators in adult patients with CRPS, the evidence is weak (Bogduk, 2002 ; Sharma et al., 2006 ). Response to sympathetic ganglion blockade success could not be predicted from any of the presenting signs or symptoms (Sethna and Berde, 2012 ; van Eijs et al., 2012 ). Steroids Glucocorticoids are commonly used anti-infl ammatory drugs and suppress infl ammat ory process through many routes despite its limited effi cacy. It is most frequently used v ia lumbar and cau- dal epidural routes for targeting the radicular pain of L5, S1, and othe r nerve roots. Th ey exert their action by blocking the synthe- sis of prostaglandins, leuk otrienes, and platelet activating factor. Steroids also stabilize the neuronal membrane and so are used to reduce pain from neural irritability and diminish perineural infl am- matio n and oedema. Th ere is no supporting scientifi c evidence in children, but a maximum serie s of three nerve blocks are proposed, to achieve longer-term relief. Th ere is no consensus on the type or optimal dose of steroids that should be used for various central and periph eral nerve blocks in adults and no data in children. Th e most common steroid preparations used include triamcinolone, meth- ylprednisolone acetate, and dexamethasone. Even though th e fi rst two are particulate steroids with better effi cacy, the potential risk of vascular injury and infarction makes their use undesirable. Th e main risks of repeat injections of steroids are systemic absorption and Cushing \200\231s syndrome, skin atrophy, and poor he aling. Th e use of steroid for interventional chronic pain in children is not approved by F ederal Drug Administration in US (Eckel and Bartynski, 2009 ). Sympathetic ganglia blockade and/or epidural analgesia must be off ered in the context of m ultidisciplinary management of chronic pain disorders. Preliminary experience in rehabilita tion of chil- dren and adolescents with intractable CRPS reported signifi cant improvement in many domains of the child \200\231s quality of life includ- ing pain reduction, function al improvement to remission, return to normal activities, and improvement of school attenda nce aft er a 3-week outpatient intensive interdisciplinary rehabilitative pro- gramme, cons isting of physical and occupational therapies, cogni- tive-behavioral therapy, and child an d family education (Logan et al., 2012 ). Stellate ganglion blockade Th e stellate ganglion is located on the anterior surface of C7 trans- verse process. Sympathetic innervation to the head and neck arises from T1/T2 and pa sses through the stellate ganglion; and the sym- pathetic innervation to the upper extremit y arises from T2 to T8, but some fi bres synapse at the second thoracic ganglion and may no t be fully interrupted by a stellate ganglion blockade (Tong and Correct needle placement technique Although many axial and peripheral nerve blockades have tra- ditionally been performed without aids to correct placement a SECTION 6 pharmacological interventions 476 Complications Potential serious infectious complications can occur with tempo- rary epidura l catheters and SCS, particularly in immune suppressed children due to malignancy, chronic steroid therapy, chronic pain disorders or those with coexisting infection (Aram et al., 20 01 ; Olsson et al., 2008 ; Sethna et al., 2010 ; Straff ord et al., 1995 ). In a large pedi atric population the incidence of externalized (through a short subcutaneous tunnel) tunnel ed epidural catheter-associ- ated cellulitis, paravertebral muscle, and epidural space infe ctions was evaluated and signifi cantly higher rate of infection was found in children with CRPS when compared to postoperative children: 3.2% versus 0.06% (Sethna et al., 2010 ). Th e median duration of epidural infusion was similar in the two groups of patients (3 versus 4 days, ranging 1 \200\22312 days). Th e diagnosis of the infection in CRPS children (10 \200\22316 years) was made between 3 and 5 days aft er inser- tion of the catheters. All CR PS children were otherwise healthy whereas the children who developed postoperative epidura l cath- eter-associated infection were immunosuppressed due to malig- nancy and/or chronic steroid therapy. Th e most common pathogen was Staphylococcus aureus . Th e reasons for the higher incidence of infection in otherwise healthy CRPS children are not entirely understo od, but are attributed to impaired immune response caused by chronic pain and stress. Nelson, 2000 ). Blockade is achieved by injection of 3 to 5 ml of local anesthetic; larger volumes may spread to the somatic nerve via epidural sleeves, or cause serious systemic tox icity if inadvertently injected in a vessel (particularly the nearby vertebral artery). Sig ns of successful sympathetic blockade include: ipsilateral Horner \200\231s syndrome, nasal congestion, cutaneous vasodilation, and increased cutaneous temperature in the arm. Stella te ganglion blockade is infrequently performed in children because CRPS aff ects pre- domin antly the lower extremity. Recent cases report use for post- traumatic headache, and pain m anagement of acute herpes zoster ophthalmicus using an indwelling catheter for injection of a series stellate ganglion blockade (Agarwal and Joseph, 2006 ; Chan and Chalkiadis, 2010 ; Elias and Chakerian, 1994 ). Lumbar sympathetic blockade Th is procedure is the more commonly performed in children for management of CRPS-I which predominantly aff ects the lower extremity (80 \200\22390%). It is typically performed at L2 to L3 level, and the technique is similar to that described in adults (Meier et al., 2009 , Sethna and Wilder, 1993 ). Successful sympathetic blockade is indicated by interruption of sympathetic innervation to the skin manifested by vasodilatio n, increased blood fl ow and rise in skin temperature of the ipsilateral limb (Irazuzta et al., 1992 ; Krumova et al., 2011 ). Despite widespread use of sympathetic blockade in pain management clinics, only a few controlled trials have shown signifi cant diff erences betwe en sympathetic blockade and control. Systematic reviews have concluded that the overall evi dence for therapeutic benefi t for temporary or neuroablative sympathetic interruption for CRPS is weak (Sethna and Berde, 2012 ). Spinal cord stimulation (SCS) for intractable CRPS Adult controlled trials of intractable C RPS reported that SCS sig- nifi cantly reduced pain (more than 50%) with SCS, but did not a lleviate sensory abnormalities of allodynia or improve function (Kemler et al., 2004 ). Reg rettably, the long-term benefi t at 3-year follow-up waned and was not statistically diff e rent compared to control group. Th e benefi t of SCS for management of challenging cases of CRPS-I in children has been reported in one retrospec- tive review of 7 children ages 11 t o 14 years who benefi ted tran- siently from sympathetic blockade with local anesthetic (Ol sson et al., 2008 ). Th e duration of SCS ranged from 3 weeks to 4 years. Th e pain allevia tion onset occurred aft er 1 to 2 weeks and complete relief at 2 to 6 weeks in fi ve patien ts, which persisted for 1 to 8 years; but in two patients the there was only partial relief . In one patient aft er a few-day trial, the SCS was removed due to local infection, but th e pain reduction persisted, and a recurrence some months later resolved spontaneously. Foll ow-up data were collected via tel- ephone interviews and only three out of seven patients r esponded favorably to the question \200\230Would you have SCS again? \200\231. In view of the limitations of this retrospective review and invasiveness of the procedure, prospective placebo-control trials are needed before application of this intervention can be justifi e d (Olsson et al., 2008 ; van Eijs et al., 2012 ). Th e precise mechanism(s) of CRPS is complex and remains a research challenge, as it involv es somatosensory, motor, and sympa- thetic nervous systems. Potential mechanisms include: d isordered regulation of sympathetic system with sympathetically maintained pain, peripheral and central sensitization, somatosensory and body perception changes (Krumova et al., 2011 ; Price et al., 1998 ). In a few CRPS patients, a series of temporary blockade with local anesthetics leads to long-lasting pain relief (Krumova et al., 2011 ; Meier et al., 2009 ; Price et al., 1998 ), but the long-term benefi t of sympathetic blockade in children and ad ults has not been investi- gated or demonstrated (Perez et al., 2010 ; Wilder et al., 1992 ). As an alternative technique, epidural and peripheral nerve blockade with indwelling cath eters has been used for continuous infusion of local anesthetic to alleviate CRPS pain and facilitate physical therapy for mobilization of the aff ected limb (Dadure et al., 2005 ; S ethna and Wilder, 1993 ). A recent controlled trial in children with CRPS, ages 7 to 17 years, demonstrated thermal a nd mechanical quantitative sensory abnor- malities suggestive of central sensitization (Set hna et al., 2007 ). A second double-blind, placebo-controlled crossover trial by the same i nvestigators compared intravenous versus lumbar sympa- thetic blockade with lidocaine in a small number of children (ages 10 \200\22318 years) and found that a single lumbar sympathe tic block- ade produced signifi cant reduction in pain intensity in response to evoked tact ile and mechanical stimulation, mechanical temporal summation and spontaneous pain scores i n approximately 40% of the patients. Th e fi ndings of this study support the concept that in some patients a component of pain involves a sympathetic eff er- ent and somatic aff ere nt cycle of activities, and suggest that selec- tive sympathetic ganglia blockade can allev iate pain (Meier et al., 2009 ). Neuraxial blockade for intractable cancer-related pain Many of the principles and fundament al tenets of adult pallia- tive care are applied to refractory pediatric cancer and chronic non-malignant pain conditions, but bearing in mind the diff er- ences in child development , pharmacology, and the spectrum of malignancies. For the majority of children (90 \200\22395%) with cancer, pain is eff ec- tively managed w ith conventional analgesics (opioids, non-opioids, adjuvants) via parenteral, enteral, subc utaneous, and transdermal routes (Collins, 2002 ). Analgesia requires optimization as par- ents reported only 27% of children with end-stage cancer pain CHAPTER 46 interventional pain management techniques for chronic pain 477 received adequate conventional analgesia (Wolfe et al., 2000 ). Pain complaints, other than headache, were reported more commonly in children with solid tumors including brain and ne rvous sys- tem, compared to other types (leukemia, lymphoma, etc.). In last days of life 92 % of children with all types of childhood malignancy reported pain and in approximately two -thirds of these patients the pain constituted a diffi cult problem to manage (Goldman et a l., 2006 ). used opioids. Th e initial dose is estimated by conversion of the total daily dose of enter al and parenteral opioids. Th e average ratio of opioid conversion between routes, for inst ance, for morphine oral:intravenous:epidural:intrathecal is 3:1:0.1:0.01 mg respectively (K rames, 1996 ). Initially, frequent dose adjustment is required to titrate analgesic dose, c oncentrations and volume against individ- ual response. Additional small doses may be neces sary for break- through pain. In a small number of children even large doses of opioids do not adequately control pain, b ecause of development of opioid toler- ance and/or opioid-induced hyperalgesia; or because severe diff use pain, involving somatic, neuropathic, and visceral components, develops. Du ring the terminal stages of childhood malignancy, the opioid requirement may escalate expon entially to massive doses. Approximately 3% to 6% of these patients can benefi t from inter - ventional pain therapies for management of the refractory pain unresponsive to standard c ancer and conventional analgesic thera- pies, or because opioid dose escalation is limited by intolerable side eff ects such as nausea, vomiting, sedation, and obtunded mentation (Co llins et al., 1995 , 1996 ). Regular monitoring for side eff ects is required, with close nurs- ing observation, continu ous electrocardiogram, chest wall imped- ance plethysmography, and pulse oximetry. In addit ion, systemic opioids should be gradually reduced as neuraxial analgesia is titrated up, to avoid opioid withdrawal symptoms. In terminally ill children the analgesic requirement by all routes of administration may escalate to massive doses (Queinnec et al., 1999 ; Whyte a nd Lauder, 2012 ). Inadequate analgesia with neuraxial delivery has been reported in a few children with advan ced and extensive malignancy, par- ticularly with the epidural route, and which necessitate d conver- sion to intrathecal analgesia (Collins et al., 1996 ; Portas et al., 1998 ; Quein nec et al., 1999 ; Tobias, 2000 ). Children with extensive vis- ceral and pelvic malignancy refractory to intrathecal analgesia may require neurolytic intrathecal or coeliac blockade (Galloway et al., 2000 ; Patt et al., 1995 ; Shimazaki et al., 2003 ), and one rare case o f cordotomy has been reported in a 10-year-old child (Queinnec et al., 1999 ). Interventional therapies are off ered when the overall benefi ts outweigh the risks. Such t herapies include epidural, intrathecal, plexus, and peripheral nerve analgesic infusions or ablative ther- apies. Th e published experience in children is very limited but includes ( Table 46.1 ): \231 Neuraxial blockade via an epidural (caudal, lumbar, thoracic, cervical) or intrathecal catheter. Contraindications Many of the absolute contraindications for placement of epidural, intrath ecal, and peripheral nerve blockade in healthy patients are considered to be relative contr aindications in children with uncontrolled cancer pain. Advanced malignancy is associated w ith immune suppression and possible coagulopathy, but complica- tions and particularly infe ctions are surprisingly low (Anghelescu et al., 2010 ). Benefi ts should outweigh the poten tial side eff ects, and patients and their families must be fully informed of the potential serious side eff ects. \231 Externalized catheter and infusion for peripheral nerve blockade. \231 Neurolytic nerve and plexus blockade. E \203 cacy and safety of continuous infusion of neuraxial analgesics Several pediatric ca ncer case reports and small series of have reported eff ective analgesia with short-term (w eeks to months) use of externalized and internalized epidural and intrathecal catheters for infusion of various combinations of opioids, local anaesthet- ics, and clonidine ( Tables 46.1 and 46.2 ). Th e spread, absorption, and pharmacodynamics of analgesics administered v ia epidural and intrathecal routes in children are infl uenced by multiple fac- tors such a s the age, weight, height, presence of increased intra- abdominal and intrathoracic pressur e, cerebrospinal fl uid (CSF) fl ow characteristics, and patency of the epidural space. Th ere is no clear standardization or consensus for the use of various analgesics, either give n alone or in combination, in children. Most approaches are derived from pediatric acute pa in management studies and clinical experience. Th e published experience (and our own) woul d suggest starting with a single analgesic for patients who are on sys- temic opioid and ot her adjuvants such as a local anesthetic for epi- dural administration, and opioids for int rathecal administration for the fi rst 24 h. Combinations of analgesics are used when pain is not adequately controlled (e.g. an opioid plus local anesthetic and/or clonidine) to enh ance analgesia and/or reduce dose requirements of an individual analgesic agent and minimiz e the side eff ects. As the need for systemic opioids reduces a second agent may be added ( e.g. opioid to epidural solution, or local anesthetic to intrathecal solution). Morphine an d hydromorphone are the most commonly Neuraxial delivery systems A percutaneous tunneled epidural or intrathecal catheter con- ne cted to a regular syringe pump may be used when life expect- ancy is limited to days or a f ew weeks. For children with longer life expectance (weeks to a few months), an implanted de livery system is a better therapeutic option to reduce catheter displacement and the risk o f infection. Intrathecal delivery circumvents incomplete epidural absorption kinetics, irre gular spread of analgesic solu- tion, and formation of catheter tip granulomas. Smaller vol umes of analgesic are required, which is more convenient for children being cared for in th e community (Galloway et al., 2000 ; Queinnec et al., 1999 ; Tobias, 2000 ). Before proceeding with implantation of the drug delivery system, all patients must undergo a screening trial of intrathecal or epi- dural analgesia for at least 24 h to ensure pain r eduction of 50% or greater and/or reduction in opioid requirement, as well as observing for potential drug reactions. It is advisable to use fl uoroscopic guid- ance and inject contr ast to ensure correct catheter placement, and epidural catheter tips should be placed at th e optimal spinal der- matome to cover the location of maximum pain (Collins et al., 1996 ; SECTION 6 pharmacological interventions 478 Table 46.1 Continuous externalized neuraxial and peripheral nerve blockade management of in tractable malignant pain in children Reference Age (years) n Intervention Site Infusion Duration (Berde et al., 1989) 0.4 1 Epidural Caudal Intermittent morphine 1 week (Berde et al., 1990) 19 1 Intrathecal Lumbar to thoracic Bupivacaine 7 months (Plancarte and Patt 1991) 3.8 1 Epidural Th oracic Meperidine 1 month Droperidol (Meignier et al., 1992) 1.4 \200\22312 5 Intrathecal Lumbar Bupivacaine 20 days \200\2233 months Morphine Fentanyl (Veyckemans et al., 1994) 1.9 1 Epidural Cervical Morphine and 35 days Bupivacaine Intermittent (Patt et al., 1995) 3 5 Intrathecal Lumbar Phenol 10% 8 days until demise (Collins, 1996) 0.4 \200\22316 4 Intrathecal Lumbar Bupivacaine 3 days \200\2237 weeks 6 Epidural Caudal/lumbar Morphine Fentanyl Hydromorphone (Portas et al., 1998) 1 \200\22315 7 Epidural Lumbar Bupivacaine 2 days \200\2236 months Sufentanil Clonidine (Queinnec et al., 1999) 10 1 Epidural Lumbar Bupivacaine 4.8 months Morphine Clonidine (Tobias, 2000) 16 1 Intrathecal Lumbar Bupivacaine 4 weeks Sufentanil (Galloway et al., 2000) 15 1 Intrathecal Lumbar Bupivacaine 5 months Sufentanil (Aram et al., 2001) 6 7 \200\22321 Epidural Lumbar thoracic Bupivacaine, Morphine 5 \200\22354 days Fentanyl Hydromorphone (Bozkurt et al., 2005) 2.5 1 Epidural Th oracic Bupivacaine 2 weeks Fentanyl (Anghelescu et al., 2010) 4.4 \200\22321 10 Epidural Lumbar Local anesthetic 4 \200\22385 days Th oracic Opioids clonidine (Cooper et al., 1994) 6 1 Brachial plexus Bupivacaine intermittent 5 days (Anghelescu et al., 2010) 2, 3, 18 3 Femoral Ropivacaine 3 \200\22381 days Axillary Interscalene (Burgoyne et al., 2012) 14, 13, 8 3 Femoral Ropivacaine 22 \200\22341 days Brachial plexus Queinnec et al., 1999 ). In addition to meticulous attention to aseptic handling of externa lized and internalized catheters, catheters should be clearly labeled to avoid inadvertent administration of drugs not intended for epidural or intrathecal therapy. All drugs used fo r epi- dural and intrathecal administration should be preservative free to minimize the ris k of neurotoxicity. In adults, the subcutaneous Port-A-Cath \204 device has been used for delivery of opioids via epidural and intrathecal routes for long-term management of cancer and non-malignant i ntrac- table chronic pain syndromes (Dahm et al., 1998 ; Plummer et al., 1991 ). A special Port-A-Cath system \204 is designed specifi cally for analgesic drug delivery and repeate d access to the epidural or CHAPTER 46 interventional pain management techniques for chronic pain 479 Table 46.2 Clinical data on neuraxial and peripheral nerve blockade infusion reported in th e literature combinations of analgesic agents is yet to be realized with respect to effi cacy, failure r ates, and technical complications. Complications of neuraxial infusions In children, estimation of the incidence of adverse ev ents with neu- raxial infusion is not possible due to the small number of retrospec- tive c ases reported, and because many side eff ects either did not occur or were not documented. Systemic toxicity has occurred with large doses of epidural bupivacaine (3 \200\2234 mg/kg/ h) in three patients (Portas et al., 1998 ). Cases of tolerance or tachyphylaxis to opioid and/or local anesthetics were treated by converting to another analgesic with a diff erent mechanism of action, or adding clonidine to enhance analgesia (Anghelescu et al., 2010 ; Be rde et al., 1990a ; Whyte and Lauder, 2012 ). Drug-related side eff ects have included: uri nary retention, which usually improved with time (Collins et al., 1996 ; Queinnec et al., 1 999 ); constipation (Queinnec et al., 1999 ); mild reversible somnolence and respiratory de pression (Berde et al., 1990a ; Collins et al., 1996 ). Other potential side eff ects and c omplications such as nausea, vomiting, pruritus, opioid-induced myoclonus and hyperalgesia, CSF-hygroma, implantation pocket seroma, meningitis, and cardiovascular instability and de ath were not reported in these pediatric case reports. Reported catheter- related or techni cal complications include: catheter leakage and fracture (Anghelescu et al., 2010 ); epidur al catheter occlusion by tumor or kinking (Anghelescu et al., 2010 ; Collins et al., 1996 ) ; catheter dislodgement (Anghelescu et al., 2010 ; Aram et al., 2001 ), and Port-A-Cath sys tem malfunction (Queinnec et al., 1999 ); post- dural puncture headache (Collins et al., 19 96 ); and infection at the skin entry port or catheter tip (Aram et al., 2001 ; Berde et al ., 1990a ; Queinnec et al., 1999 ) Site of administration and analgesic agent a Dose Epidural opioid and clonidine (mcg/kg/h) Lumbar morphine 1 \200\2234 Lumbar hydromorphone 0.6 Lumbar fentanyl 0.4 \200\2230.5 Lumbar sufentanil 5 \200\22330 Lumbar clonidine 5 \200\22310 Cervical meperidine 5 mg three times a day Epidural local anesthetic (mg/kg/h) Lumbar bupivacaine 0.2 Th oracic bupivacaine/ropivacaine 0.2 \200\2230.3 Lumbar/thoracic lidocaine 1.5 (maximum 2) Intrathecal opioid (mcg/kg/h) Lumbar morphine 2.5 \200\223252 Th oracic and lumbar fentanyl 0.2 \200\2230.4 Intrathecal local anesthetic (mg/kg/h) Th oracic bupivacaine 0.5% 2 \200\2234 ml/h Lumbar bupivacaine 0.04 \200\2230.25 Th oracic bupivacaine 0.01 \200\2230.12 Intrathecal clonidine 0.04 \200\2230.9 Peripheral nerve blockade Plexus blockade for intractable malignant and chronic non-malignant pain Th e coeliac plexu s is located at the T12/L1 vertebral level, anterior to the aorta and crus of the diaphragm , and supplies sympathetic innervation to the upper abdominal viscera (liver, gall bladder, spleen, stomach, pancreas, kidneys, small bowel, and proximal two-thirds of the large bowe l). Th e preganglionic sympathetic innervation consists of T5 to T12 spinal segments. It su pplies sympathetic supply to greater splanchnic nerve (T5 \200\22310), lesser splanchnic ne rve (T10 \200\22311) and least splanchnic nerve (T11 \200\22312) (Loukas et al., 2010 ; Kam badakone et al., 2011 ; Puli et al., 2009 ). Th e standard coeliac plexus blockade is perfo rmed in adults with the aid of imaging or under direct vision during surgery (Arcidiacono e t al., 2011 ; Kambadakone et al., 2011 ; Levy et al., 2012 , Sharma et al., 2011 ). Femoral nerve ropivacaine 0.2 \200\2230.4% 10 \200\22312 ml/h for 81 days Interscalene ropivacaine 0.2% 8 \200\22312 ml/h for 35 days a Th e lower rates of infusion are for initial dosing. Th e higher rates of infusion of opi oids and/or local anesthetics were administered to children tolerant to opioids. intrathecal space. A subarachnoid or epidural silicon catheter is tunneled subcutaneously t o a small reservoir that has a self- sealing silicone septum for needle insertion and conne ction to an external infusion device. Successful use of epidural or intrath- ecal Port-A-Ca th system \204 has been reported in pediatric case reports for delivery of opioid, local anesthetic and clonidine ( Table 46.1 ) (Galloway et al., 2000 ; Queinnec et al., 1999 ; To bias, 2000 ). In one case the Port-A-Cath system \204 was used for epi- dural analgesia o n four occasions with eff ective analgesia over 143 days. Complications occurred on two occ asions: a catheter dysfunction, and abscess that necessitated removal of the system (Queinn ec et al., 1999 ). Coeliac plexus blockade is primarily indicated for cancer and life limiting/terminating con ditions. Th e principles of pain man- agement and palliative care in adults are incorporate d in the care of children with cancer, including use of neurolytic blockade. Drugs (e.g. al cohol, phenol) and dosing regimens in pediatric case reports have been based on the age of the child and extrapola- tion from adult experience. Neoplastic diseases such as pancreatic and hepatic malignancies can produce intense pain from stretch, compression, invasion, or distension of the visceral structures. Neurolysis of the coeliac plexus is an important adj unct for relief of intractable pain, aiming to optimizing analgesia and reduce the need for , and adverse eff ects of, opioid and non-opioid analgesics. As neurolytic blockade is asso ciated with potential serious side In the past decade fully implanted intrathecal pumps have been used for infusion of baclofe n to manage intractable spasticity. Th e drawbacks of this system are potential technical p roblems, it requires a surgical procedure and a special percutaneous needle and kit for acc essing and refi lling the pump reservoir, and the high cost makes it impractical for childr en with cancer-related pain and limited life expectancy. Although the use of subcutaneous implanted systems in chil- dren is appealing, in reality t he full potential for delivery of various SECTION 6 pharmacological interventions 480 eff ects, this modality of intervention is off ered when the benefi ts clearly outweigh the potential risks. a few retrospective reviews and one prospective study in small numbers of pediatric patient s (Krane and Heller, 1995 ; McGrath and Hillier, 1992 ; Melzack et al., 1997 ; Simmel, 1962 ; Smith and Th ompson, 1995 ; Th omas et al., 2003 ; Wilkins et al., 1998 ). Th e current pharmacotherapy is inadequate to completely prevent or alleviate the pain aft er limb amput ation in children and adults. Th e development of PLP is best conceptualized as multifactor ial and treatment requires a multimodal approach. See elsewhere in this volume for further description of PLP (Walker, Chapter 21), and for pharmacological management options (Rastog i and Campbell, Chapter 48). While PLP cannot be entirely prevented aft er surgery, growing anecdotal data suggests that perioperative neuraxial and peripheral nerve blocks in additi on to systemic analgesics may minimize the immediate and short-term post-amputation PLP. A recent review of cancer amputee children and young adults reported a very lower incidence o f only 10% of PLP at 1 year aft er amputa- tion (Burgoyne et al., 2012a ). In this review 1 7 out of 25 patients had pain prior to amputation and the low incidence post-surgical PLP w as partly ascribed to the preoperative pain management. Th is included administration of ga bapentin in all patients and continu- ous epidural or continuous peripheral nerve blockade in 21 out of 26 cases. In children, CT-guided coeliac blockade has safely achieved eff ective pain management in a small number of patients aged 3 to 7 years. Reported cases include: \231 Neurolytic block for management of refractory upper abdomen visceral pain from cance r (Berde et al., 1990b ; Staats and Kost- Byerly, 1995 ). \231 Neurolytic splanchnic nerve blockade in an 18-year-old with mitochondrial neurogastr ointenstinal encephalopathy and supe- rior mesenteric artery syndrome for management of int ractable abdominal pain, which resulted in pain relief at one-year fol- low-up (Celebi et a l., 2006 ). \231 Diagnostic and temporary treatment of acute on chronic pan- creatitis with local ane sthetic and steroid (Attila et al., 2009 ; Goldschneider et al., 2007 ). \231 Chronic abdominal pain due to infl ammatory bowel disorder (Tanelian and Cousins, 19 89 ) or due to neurodegenerative disor- ders (Goldschneider et al., 2007 ; Teitelbaum et al ., 2002 ). Superior hypogastric plexus blockade (anterior to lower third of L5 and upper two-thirds of S1 vertebral bodies) has been used in adults for management of intractable pain of the pel vic organs and descending colon and rectum as well as perineal hyperhidrosis (Schmidt et al ., 2005 ; Nabil and Eissa, 2010 ). Epidural steroid injection (ESI) Th e indication for ESI is local alleviation of perineural infl amma- tion of the spinal nerve roots that are irritated or compressed by herniated nu cleus pulposus, annular tear, spinal stenosis and post- laminectomy syndrome. Fluoroscopic- guidance is used to place steroid in the vicinity of the aff ected nerve roots. Evidence fo r ESI is restricted to adult practice, predominantly for radicular pain that radiates along the distribution of a specifi c spinal nerve distally below the knee. Radicular pain is ne uropathic pain in the distribu- tion of specifi c spinal nerve roots, and can arise from me chani- cal or chemical irritation due to a herniated nucleus pulposus or spondylosis with s tenosis of nerve pathways (Manchikanti et al., 2012 ). Ganglion impar , a small ganglion formed by convergence of the two pelvic sympathetic trunk s in front of the sacro-coccygeal junc- tion, supplying perineum, distal rectum, anus, dist al urethra, vulva and distal third of the vagina. A trans-sacrococcygeal block with local a nesthetic successfully managed chronic post-traumatic coc- cydynia in an adolescent (Ellina s and Sethna, 2009 ). Neurolytic blockade, with appropriate imaging and confi rmation of a suc- cessful diagnostic local anesthetic block, has been used for adult malignant pain cond itions unresponsive to conventional treatment (Lin et al., 2010 ). Interlaminar epidural steroid injections may be performed in the cervical and lumbar spine using the traditional loss of resistance technique. For accurate placement of the needle, w ithin the epi- dural space and close to the aff ected nerve fl uoroscopic guidance is recom mended to avoid misplacement of the needle and con- fi rm spread of contrast medium in prox imity to the target spinal nerve. In adults, typical injectate is 80 mg (2ml) of triamcinol one. In the lumbar region a small amount of local anesthetic is added to produce pain relie f. In the cervical spine local anesthetics are avoided to minimize excessive cephalad sprea d of the injectate (Manchikanti et al., 2012 ). Interventional pain management for intractable acute and chronic pain Neuraxial blockade Sa fe and eff ective (defi ned as decrease in mean dose of opioid requirement) use of short-te rm caudal, lumbar and thoracic epi- dural infusions via tunneled catheters are also reporte d in a small number of 14 children and adolescents, a mean age 4.4 years, and a mean durati on of 16 days (range 5 \200\22314 days) for management of pain following trauma, extensive surgery and CRPS type I (Aram et al., 2001 ). Long-term continuous peripheral nerve block h as also been used for management of severe pain from pathological fracture of the femur in 3 children, aged 8, 13, and 14 years, with osteosarcoma while awaiting chemotherapy and sur gical treatment. Th e duration of the externalized catheters was 22 to 41 days with signifi cant reduction in pain and opioid use, and without complica- tions related to the catheter , infection or local anesthetic toxicity (Burgoyne et al., 2012b ). Transforaminal epidural steroid injections is intended to deposit the medication around the nerve root sleeve for more accurate tar- geting of the aff ected nerve in the anterior epi dural space where disc herniation occurs. It is primarily performed in the lumbar spine und er fl uoroscopic guidance. In adults, typical dose is 40 mg (1ml) of triamcinolone, with or without a small amount of local anesthetic (Manchikanti et al., 2012 , Quraishi, 2012 ). Selective spinal nerve blockade (SNRB) is a diagnostic technique to determine if a specifi c nerve root is the source of pain prior to surgical removal of the off ending ruptured int ervertebral disc. Th e needle tip is placed just outside of the neural foramen, lateral to the position for transforaminal ESI site but outside the foramina. Phantom limb pain (PLP) In children, the clinical characteristics, preventive measures and treatment of PLP have not been investigated rigorously, with only CHAPTER 46 interventional pain management techniques for chronic pain 481 Peripheral nerve blockade Many diff erent types of peripheral nerve blockade have been uti- lized for either diagnosis or management of various chronic pain syndromes. Local anesthet ic blockade can provide several hours of pain relief, and may aid in diagnosis or predict r esponses to sus- tained pain relief following prolonged nerve blockade techniques. Steroid provides lasting relief in cases of perineural infl ammation from entrapment syndromes. Com mon peripheral nerve blockade used in management of adult chronic pain are described below, but for the majority evidence is limited. For many, pediatric use is pre- dominantly for a cute or perioperative pain, and the role for chronic pain management is unclear. Caudal epidural steroid injection is performed by a technique similar to that performed for caudal anesthesia, with lateral fl uor- oscopy to visualize the spread of contrast medium (Parr et al., 2012 ). Facet joint pain Th e facet joint is formed by articulation of processes of two adja- cent vertebrae and the joint capsule is innervated by a medial nerve branch. Th e joint is susce ptible to chondral damage (e.g. whiplash injury, repetitive strain, sports injury), infl am mation and degenera- tion (e.g. congenital, post-surgical spinal fusion, old age). Estimati on of the true incidence of facet joint pain is diffi cult because the diag- nosis cannot b e made by history, physical examination or imaging, and the most reliable diagnostic test i s response to intra-articular or medial nerve branch blockade (Schwarzer et al., 1994a , 19 94b ). Although some studies report pain relief up to one year, the lack of RCT crossover s tudies precludes drawing defi nitive conclusions about specifi city of this blockade. Trigeminal nerve blockade Th e sensory aff erent inputs from the orofacial structures that sense mechanical, thermal and pain stimuli are served by the fi ft h (trigeminal) cranial n erve, and divided into: \231 Ophthalmic branch innervates nasal and frontal sinuses Intra-articular facet blockade is performed with local anaes- thetic and steroid, and repea t injections may be required to relief fl are-ups. If the pain recurs some practitioners co nsider positive response to steroid injection a criterion to perform radiofrequency lesioni ng for providing prolonged pain relief (Atluri et al., 2008 ; Boswell et al., 2007 ). mucosa. \231 Maxillary branch innervates the nares, upper teeth and gums, nasal mucosa, palate an d roof of the pharynx, maxillary, eth- moid, and sphenoid sinuses. \231 Mandibular branch innervates the lower teeth and gums. Th e trigeminal system is the main source of sensory innervations to the supra-tentorial dura, venous sinuses and mening eal arteries. Medial branch nerve blockade (MBB) interrupt pain conduction by nerves that innervate the f acet joints. MBB is performed using a local anesthetic alone or in combination with steroid s, potentially followed by a series of blocks, or radiofrequency lesioning to pro- vide pro longed pain relief. Th e sensory aff erent input projects to the trigeminal (Gasserian) ganglion. Th e trigemin al brainstem sensory neuron complex receives descending inhibitory modulation from higher c enters (periaqueductal gray, reticular formation and sensory-motor cor- tex) mediated throu gh release of neuropeptides including endog- enous opioids, noradrenaline, 5-HT, and GABA t hrough synaptic connections (Sessle, 2000 ). Radiofrequency nerve lesioning (RFNL) (thermo-coagulation or thermal injury) is utilized to interrupt nerve conduction for 6 to 9 months. Although RFNL is used for interruption of va ri- ous nerves, e.g. peripheral (e.g. occipital neuralgia), visceral (e.g. splanchnic) and sympathetic (e.g. CRPS), presently it is prima- rily used for the treatment of axial back p ain produced by facet and sacroiliac joint arthropathy, and therefore is most oft en used i n adults (van Boxem et al., 2008 ). Pulsed RFNL was introduced recently because of a wider margin of safety, and to expand the application of this therapy to various peripheral neuro pathies, joints arthropathy and painful trigger points as well as treatment of facet joints , sacroiliac joints, dorsal root ganglion, stellate gan- glion, Gasserian ganglion and inte rvertebral disks (van Boxem et al., 2008 ). Th e classic presentation of trigeminal neuralgia (TN) is parox- ysms of lancinating pain, which occur in the territory of one or more trigeminal nerve branches, associated with musc le spasms in the absence of sensory and motor defi cit. Th e pain is easily trig- gered by non-noxious stimuli such as minor mechanical stimula- tion or light touch. Trigeminal neura lgia is rare in the pediatric age group, with case reports of typical (at ages 1.5, 6, 9, a nd 12 years) and atypical (at 9 years) TN described. Th e youngest child in whom TN was ret rospectively suspected was 13 months of age; the child suff ered pain attacks for years bef ore TN was fi nally diagnosed at age 7 years (Bender et al., 2011 ).