CM E Management of Childhood Spasticity: A Neurosurgical Perspective Christopher E. Mandigo, MD; and Richard C.E. Anderson, MD S pasticity is a vexing problem for or damage to the developing CNS. Spas- both healthcare providers and pa- ticity is demonstrated in children as in- tients. Cerebral palsy is the most creased muscle tone, persistent primitive common cause of spasticity and physical reﬂexes, and delay of normal motor skills. disability in children. It deﬁnes a range of Spasticity inhibits effective use of motor nonprogressive syndromes of posture and control and strength and can lead to pro- motor impairment that results from an gressive musculoskeletal complications insult to the developing central nervous such as joint and muscular contractures, system (CNS) either in utero or within bony deformation, and joint subluxation the ﬁrst 2 years of life.1 The prevalence or dislocation.5 Proper treatment for spas- of cerebral palsy is not known but is esti- ticity can halt progression of contractures mated at approximately 2 per 1,000 chil- or deformity and often can return func- dren, and its incidence may be increasing tion to affected limbs. Both prospective secondary to improved care in neonatal and retrospective studies of children intensive care units and improved surviv- treated for spasticity have demonstrated al of low birth-weight infants.2 The com- improved ease of caregiving, decreased mon features of cerebral palsy include pain, and improved quality of life.6 movement disorders, muscle weakness, Spasticity in children can result from ataxia, rigidity, and spasticity. any disease process that affects the upper Spasticity is deﬁned as a velocity- motor neuron within the CNS. Injury to dependent increased resistance to pas- the upper motor neuron decreases corti- sive muscle stretch, or alternatively as cal input to the descending reticulospinal inappropriate involuntary muscle activity and corticospinal tracts, which causes associated with upper motor neuron pa- weakness, loss of motor control, and re- ralysis.3,4 It is a hallmark of cerebral pal- duction in the number of voluntarily ac- sy but can occur with other genetic and tive motor units. The reduction of these metabolic diseases that cause dysfunction descending tracts removes the normal 354 PEDIATRIC ANNALS 35:5 | MAY 2006 inhibition of the reﬂex arcs within the evidence of hemorrhage, hydrocephalus, other healthcare professionals, is best grey matter of the spinal cord, leading to or structural abnormalities of the CNS. suited to treat children with spasticity. a hyperactive reﬂex arc and spasticity. Spasticity is most commonly quantiﬁed Therapy should be guided by the clini- The diagnosis of spasticity requires by the Ashworth spasticity scale (Table cal scenario and speciﬁcally targeted at a complete history and physical exami- 1, see page 356).7,8 treating pain, decreasing tone, and re- nation, with ancillary testing as needed. ducing muscle contractures, joint defor- The history should inquire about pos- MANAGEMENT mities, and abnormal motor control. sible gestational and perinatal events Treatment of spasticity involves mul- Spasticity should be addressed at an and motor and cognitive development. tiple modalities that most commonly early age to prevent permanent contrac- The physical examination should focus include observation, physical and oc- tures, joint subluxation, dislocation, and on motor power, muscle tone, active cupational therapy, orthotics, oral medi- bony deformity. In general, young children and passive range of motion of joints, cines, intramuscular injections, and both generally respond well to physiotherapy, sensation, deep tendon reﬂexes, station neurosurgical and orthopedic surgery. orthotics, intramuscular injections, and (pelvis and leg alignment while stand- A combination of methods is employed neurosurgical procedures. Older children ing), presence of limb deformity, spinal most often to increase the beneﬁcial ef- beneﬁt from these therapies as well but alignment, and extent of movement dis- fects of each modality synergistically. A also may need orthopedic surgery to ad- orders. Ancillary testing usually includes multidisciplinary team, including pedia- dress musculoskeletal deformity. imaging studies such as cranial ultra- tricians, physical and occupational ther- An approach directed by the location sound, computed tomography, or mag- apists, neurologists, orthotists, orthope- and severity of the spasticity is used to netic resonance imaging to evaluate for dic surgeons, neurological surgeons, and identify the appropriate therapeutic in- PEDIATRIC ANNALS 35:5 | MAY 2006 355 tervention. These therapies should be TABLE 1. directed toward achieving goals deter- mined in concert with caregivers, and Ashworth Scale of Muscle Tone4,7 ideally should be monitored by the use Ashworth Scale Degree of Muscle Tone of clearly deﬁned outcome measures.6 1 No increase in tone 2 Slight increase in tone, “catch” when limb is moved Nonpharmacologic Therapy 3 Marked increase in tone, passive movements difﬁcult Physical and occupational therapy, 4 Considerable increase in tone, passive movements difﬁcult orthotics, and casting are just a few 5 Affected part is rigid in ﬂexion or extension of the nonpharmacologic and surgical therapies employed to improve joint range of motion, strengthen muscles, in- hibit spastic agonist muscles, and assist Oral Medications cal situation and age of the patient as the with motor development. There is a lack Oral medicines are used often to re- natural course of speciﬁc musculosk- of evidence-based information address- duce spasticity. The most common agents eletal abnormalities is factored into the ing these therapies for the treatment of are baclofen, diazepam, dantrolene, and decision-making process. spasticity, largely because commonly tizanidine. These have different mecha- used outcome measures have not been nisms of action with the common goal Neurosurgical Therapy validated or may not be functionally of reducing spasticity. Several medi- The role of the neurosurgeon in the relevant.9 However, decades of clinical cines are summarized in Table 2 (see treatment of spasticity is essential. A experience support their use for maxi- page 357). Additional novel agents that variety of surgical procedures and treat- mizing the beneﬁt of medical and surgi- are under investigation include canna- ment options have a proven long-term cal intervention. binoids, gabapentin, and 4-aminopyri- and signiﬁcant effect on spasticity in dine. Although improvements in clinical appropriately selected patients. These CM E EDUCATIONAL OBJECTIVES measures of spasticity have been noted procedures include chemical or surgical with several of these medications, few neurotomies, botulinum toxin injections, 1. Recognize the importance of early identiﬁcation and intervention in have shown signiﬁcant functional ben- selective dorsal rhizotomy, and chronic an infant or child with spasticity. eﬁt. Unfortunately, limiting side effects intrathecal baclofen therapy. 2. Discuss the pathophysiology of often are reached before a clinically sig- Selective neurotomy. Selective neu- upper motor neuron lesions and niﬁcant effect of the medication can be rotomy, or surgical and chemical lesion- their effects on muscle. obtained. Antispasmodic medications ing of peripheral nerves, has been prov- 3. Describe the management of a are very useful adjuncts to more invasive en to be effective in treating spasticity. child with spasticity and the cre- therapies and physiotherapy.10 This can be accomplished in three ways: ation of a care plan, including phar- macologic and surgical options. through surgical exposure and transec- Orthopedic Surgery tion of all or a portion of the nerve; Dr. Mandigo is resident and Dr. Ander- A wide variety of surgical options are through injection of ethanol or phenol son is assistant professor, pediatric neu- available for the orthopedic surgeon to around the nerve; or through blockade rosurgery, Department of Neurological treat spasticity and its long-term conse- of the neuromuscular junction by botu- Surgery, The Children’s Hospital of New quences on the musculoskeletal system.1 linum toxin injection. Recently, ethanol York, Columbia University, New York, NY. In general, orthopedic procedures have and phenol injections have largely been Address reprint requests to: Richard C.E. been used to improve the biomechanics set aside, as the favored technique has Anderson, MD, Division of Pediatric Neu- of spastic patients. Some common goals become botulinum injection of spastic rosurgery, Columbia University Medical of surgery include lengthening of con- muscles. Center, 710 W. 168th St., 2nd Floor, Neu- tracted muscles, balancing of joint forces, The objective of surgical neuroto- rological Institute, New York, NY 10032; or reduction of joint subluxation, fusion of my is to expose and isolate the nerve e-mail email@example.com. unstable joints, and dimishment of pain- branches that supply the spastic muscle. The authors disclosed no relevant ﬁ- ful spasticity. The surgical techniques in- A complete or partial division is then nancial relationships. clude tenotomy, arthrodesis, osteotomy, performed depending on both the par- and tendon transfer or lengthening. The ticular muscle involved and a pre-opera- procedures used are tailored to the clini- tive plan designed to balance spasticity 356 PEDIATRIC ANNALS 35:5 | MAY 2006 with motor weakness. The technique in- not currently approved by the Food and denervating a spastic muscle. Although volves intra-operative neurophysiologic Drug Administration for spasticity, BTX speciﬁc timing varies, the effects of BTX monitoring and active stimulation of the has been used clinically since 1988 to generally begin after 1 to 3 days, peak nerves to better target destructive lesion- treat spasticity associated with cerebral around 21 days, and usually have little ef- ing. Stimulation also may provide some palsy. At least two subtypes are available fect after 3 to 4 months. The dose of BTX guidance to muscle strength and how it in the United States, BTX-A (Botox) and injected varies according to the muscle relates to the amount of nerve lesioning BTX-B (Dysport). size and formulation of the toxin, but in that is acceptable before motor function general a dose of 2 to 6 U per kilogram of is lost completely. body weight is used.12 BTX can be inject- Percutaneous neurotomy is performed The physical examination ed into spastic muscles with or without by injecting either alcohol or phenol to the use of electromyography guidance. sclerose the nerve, which causes partial should focus on motor power, A number of randomized clinical tri- or complete destruction of the nerve muscle tone, active and als have demonstrated the efﬁcacy and supply to muscles. Localizing the nerve safety of BTX injections.13-16 These trials is performed with anatomic landmarks passive range of motion of have demonstrated a signiﬁcant reduc- and neurophysiologic testing through joints, sensation, deep tendon tion in spasticity and improved function the needle. The relative indications for in both lower and upper extremities. The selective denervation are spasticity, joint reﬂexes, station (pelvis and leg drug has a very good safety proﬁle and imbalance secondary to spasticity, and has infrequent side effects, mostly related decreased function. Ethanol is used more alignment while standing), to an allergic reaction to the medicine.17 in children because it is less caustic than presence of limb deformity, Selective dorsal rhizotomy. Selective phenol to surrounding tissues. dorsal rhizotomy (SDR) derives from Ethanol and phenol denervation lasts spinal alignment, and extent of late 19th Century procedures for spastic- about 3 to 8 months. Potential compli- movement disorders. ity, during which a complete rhizotomy cations and side effects include pain, was performed — the entire nerve root permanent muscle ﬁbrosis, and dyses- within the spinal canal was transected. thesias. The obturator nerve is the most When BTX is injected into spastic These initial attempts effectively elimi- commonly targeted nerve. Lesions in the muscle tissue, it acts at the neuromus- nated pathologic tone and spasticity but nerve can help stop or prevent progres- cular junction to inhibit the release of resulted in clinical failure because of sive subluxation secondary to hip adduc- acetylcholine and balance muscle forces complete loss of motor function, pain tor spasticity. across the joint.11 BTX acts locally, so it sensation, and proprioception function. Botulinum toxin injections. Botuli- is not effective in reducing global spas- The procedure was abandoned until the num toxin (BTX) injections have been ticity. The general indications for BTX 1960s, but a modiﬁcation of this ap- used increasingly in place of alcohol and are for temporary management of focal proach has now been accepted as an ef- phenol for chemodenervation. Athough spasticity and to evaluate the effects of fective treatment for spasticity. TABLE 2. Oral Medications Used in the Treatment of Spasticity Medication Mechanism of Action Half-Life Initial Dosage Maintenance Side Effects 20 to 90 mg/day Drowsiness, ataxia, Baclofen (Lioresal) GABAB agonist 3 to 4 hrs 2.5 to 10 mg/day (in three doses per day) confusion Benzodiazepine receptor 0.1 to 0.8 mg/kg/day Diazepam (Valium) 3 to 6 hrs 0.1 to 0.2 mg/kg/day Lethargy, tolerance agonist (in three doses per day) Impedes Ca2+ inﬂux into 12 mg/kg/day Weakness, diarrhea, Dantrolene (Dantrium) 3 to 9 hrs 0.5 to 1.0 mg/kg/day muscle (in four doses per day) rash, liver Alpha-2 adrenergic agent; 8 to 24 mg/day Sedation, dizziness, Tizanidine (Zanaﬂex) 2 to 3 hrs 4 to 8 mg/day inhibits aspartate output (in four doses per day) hypotension PEDIATRIC ANNALS 35:5 | MAY 2006 357 Figure 1. Schematic drawings representing the excitatory and inhibitory inﬂuences on the spinal cord alpha motor neuron, which innervates the muscle ﬁbers. (A) Normal physiology with a balance of inhibitory inﬂuence from descending neurons and excitatory inﬂuence from the sensory spinal reﬂex arc. (B) In children with spasticity, injury to the upper motor neuron results in a decrease in the descending inhibitory inﬂuence, leaving a hyperactive spinal cord reﬂex arc. By cutting some of the dorsal rootlets, selective dorsal rhizotomy can help restore balance to the alpha motor neuron by reducing the amount of excitatory inﬂuence on the alpha motor neuron. SDR was made possible after the ex- on the activity of the alpha motor neu- Traditionally, surgery for SDR has in- act anatomical localization of the Ia sen- ron. These interneurons generally have volved a 5- to 6-inch skin incision and a sory input to the spinal cord at the dorsal an inhibitory effect on the alpha motor ﬁve-level laminectomy or laminoplasty. root entry zone (DREZ) by Sindou in neuron and are activated by descending More recently, SDR can be performed 1974.18 It is believed that these sensory input from cortical upper motor neurons using a minimally invasive approach. ﬁbers help mediate the abnormal reﬂex (overall inhibitory inﬂuence to the mus- Surgery now can be done through a arc in spasticity. In principle, selective cle). On the other hand, interneurons are small (approximately 1- to 2-inch) in- lesioning of these ﬁbers could result in inhibited by the local spinal reﬂex arc, cision over the lower back and a single loss of tone without loss of other sensory which are mediated by Ia sensory ﬁbers level lumbar laminectomy.20 Intraop- input or motor control at that spinal cord (overall excitatory inﬂuence to the mus- erative ultrasound is used to conﬁrm the level. This ﬁnding was further supported cle). With damage to the brain or spinal location just caudal to the conus, and by the discovery of neurophysiological cord, the balance of input is disrupted the dura is opened to expose the conus techniques that help differentiate nerve and the reﬂex arc becomes hyperactive, and nerve roots. Individual dorsal nerve rootlets responsible for spasticity from leading to increased limb tone and spas- rootlets are then tested using electri- normal rootlets uninvolved in the dis- ticity. By selectively lesioning sensory cal stimulation and neurophysiological ease process. This method, originally nerve rootlets, SDR reduces the amount monitoring. Sensory rootlets that result described by Fasano, uses electric stim- of Ia sensory input and helps restore a in spastic responses when stimulated are ulation of dorsal sensory rootlets with more normal balance to the alpha motor identiﬁed as “abnormal” and transected 30 to 50 hertz sustained impulses to ac- neuron (Figure 1). according to a pre-operative plan based tivate the hyperactive reﬂex arc.19 These SDR is used primarily to treat chil- on the patient’s pattern of spasticity stimulated motor responses are thought dren with lower extremity spasticity, (Figure 2, see page 359). The physical to occur in the abnormal nerve rootlets or spastic diplegia. Decades of clinical therapy team is very helpful in the oper- because of the loss of descending corti- experience suggest that the patients who ating room to manually palpate muscle cal inhibitory pathways. ultimately beneﬁt the most from SDR are groups and provide physiological feed- The ability of SDR to reduce spas- those with pure spasticity involving the back during stimulation. ticity can be explained by the current lower extremities, normal intelligence, Recovery from surgery typically pathophysiological understanding of good strength, no ﬁxed contractures, and takes 2 to 3 days, followed by discharge spasticity. Motor control and tone of the postural stability. The ideal patient age to home with intensive outpatient re- muscle ultimately are controlled by the is still not known and is probably best habilitation or to acute inpatient reha- alpha motor neuron in the spinal cord. determined by the individual clinical bilitation. Long-term physical and oc- Interneurons within the spinal cord scenario. The typical age ranges from 3 cupational therapy is employed to insure grey matter have a regulatory inﬂuence to 8, but adolescents beneﬁt as well. optimal outcomes. 358 PEDIATRIC ANNALS 35:5 | MAY 2006 One Dorsal Root Normal EMG: Fascicle function in children with spastic diple- Conus Under Placed Behind Silastic gia. Interestingly, multivariate analysis Cotton Patty in the selective dorsal rhizotomy group Scheer Needle also revealed a direct relationship be- tween percentage of dorsal root tissue transected and functional improvement. A review of the literature supports the B C D ﬁndings summarized in Table 3. Tetanic Stimulation Complications occasionally can be Peacock Rhizotomy Probes of Fascicle seen following SDR, the most common Short Burst Nerve Roots being pain or transient neurologic dys- Stimulus to Whole to be Tested Sectioned function including weakness, sensory Dorsal Root Fascicles loss, or bladder dysfunction. The major- Spared Fascicles ity of these are temporary, with perma- A F nent dysfunction occurring in less than E 5% of patients. Retrospective studies Abnormal EMG: Fascicle Sectioned, have drawn attention to the possibility Placed Behind Silastic of an increased incidence of scoliosis and hip subluxation after SDR. Because Figure 2. Illustration of steps shows sparing and sectioning the dorsal root fascicles during selective these conditions are common in chil- dorsal rhizotomy. (A) An innervation pattern of each dorsal root is examined by electromyographic (EMG) responses to electrical stimulation with a threshold voltage. (B) A dorsal root is subdivided into dren with spasticity who do not undergo four to seven smaller rootlets of equal size. (C) The rootlets are tested for EMG responses. (D) Rootlets SDR, it is unclear what role SDR plays spared from sectioning are placed behind and covered by the Silastic sheet. (E) Rootlets producing 3+ in the development of scoliosis or hip or 4+ responses are sectioned. Bipolar cautery is seldom used for hemostasis. (F) Dorsal roots remain- ing over the Silastic sheet are those requiring EMG examination. Spared rootlets are placed behind the subluxation.23-25 It remains to be seen Silastic, and sectioned rootlets are left on the side of the Silastic. No dorsal rootlet is left over the Silastic if minimally invasive SDR through a after the EMG testing and the sectioning of the dorsal rootlets are completed.29 single level laminectomy rather than a multilevel laminectomy reduces the in- There have been a number of ex- or physiotherapy alone. Outcome mea- cidence of these conditions. cellent long-term outcome studies for sures were used for spasticity (Ashworth Baclofen. Baclofen was ﬁrst used pa- SDR. The outcome measures examined scale) and function (Gross Motor Func- rentally for spasticity in the late 1960s. include muscle tone, ﬂexibility, gait tion Measure) and applied at a 12-month Baclofen works as an agonist of gamma pattern, functional positioning, and the follow-up visit. As shown in Figure 3 aminobutyric acid (GABA) at GABA-B ability of the child to deal with his or her (see page 360), selective dorsal rhizot- receptors within the dorsal horn of the environment. Nearly all studies investi- omy with physical therapy was more ef- spinal cord. Activation of these receptors gating SDR have demonstrated a signiﬁ- fective than physical therapy alone in re- is thought to inhibit the excitatory input cant and persistent decrease in spasticity ducing spasticity and improving overall to the alpha motor neuron. The effective- without a return of hypertonicity over TABLE 3. time. Improved function and ambula- tion are commonly seen regardless of Summary of Reported Outcomes the pre-operative abilities. Despite the Following Selective Dorsal Rhizotomy impressive decrease in spasticity after Class I Decrease in lower limb spasticity (Ashworth scale); up to 12 years the procedure, some patients still suffer Increase in lower extremity range of motion; up to 5 years from loss of joint mobility and require Improvement in motor function (Gross Motor Function Measure) subsequent orthopedic surgery for ten- Class II Improvement in disability (Pediatric Evaluation of Disability Inventory) and don lengthening or transfer. activities of daily living performance McLaughlin et al. reported a compar- Improvement in gait including increased stride length and velocity ative analysis and meta-analysis of three Improvement in suprasegmental effects including upper limb function and cognition randomized clinical trials in 2002.21,22 Eighty-two children with spastic diplegia Class III Reduce the need for future orthopedic procedures received either SDR and physiotherapy PEDIATRIC ANNALS 35:5 | MAY 2006 359 long term therapy with and the daily administration of care.29 A baclofen. All patients experienced decreased The second group includes those chil- dren with a spastic diparesis that use muscle tone, and there their increased tone for ambulation and were minimal compli- functional mobility. If an SDR is per- Ashworth Change cations. The safety and formed in these children, the concern efﬁcacy of chronic in- is that the signiﬁcant reduction in tone trathecal therapy in adult might impair function. ITB therapy can patients was reported be effective because the intrathecal dos- in 1993.27 A total of 93 ing can be titrated to balance tone reduc- Vancouver Toronto Seattle All P < .001 P = .003 P < .001 P < .001* patients with intractable tion with functional improvement. spasticity due to either All potential candidates for ITB B spinal cord injury, mul- tiple sclerosis, or other therapy are ﬁrst evaluated with a trial injection of intrathecal baclofen. After spinal pathology were the patient receives a thorough base- entered into a random- line evaluation by the spasticity team, GMFM Change ized, double-blind, pla- a bolus of 50 micrograms of baclofen cebo-controlled screen- is given into the spinal ﬂuid through a ing protocol of (ITB) lumbar puncture. Anti-spastic effects of test injections, and 75 intrathecal baclofen can be seen within underwent implantation 30 minutes, peak between 2 and 4 hours, of a programmable pump and wear off after 6 to 8 hours. Serial ex- Vancouver Toronto Seattle All system for chronic ther- aminatons are then performed approxi- P = .012 P = .008 P = .649 P = .008* apy. Patients were fol- mately every two hours to determine its lowed for 5 to 41 months efﬁcacy. A reduction by one point on the Figure 3. Summary of meta-analysis data after selective dorsal rhizot- omy. Ashworth change score (A) and Gross Motor Function Measure after surgery (mean = (GMFM) change score (B) are shown for those receiving physical ther- 19 months). The results apy only and selective dorsal rhizotomy plus physical therapy group of this study indicated data for individual studies and pooled meta-analysis. Interval is from The objective of surgical baseline to 12 months after beginning treatment (9 months for Van- that intrathecal baclofen couver). Boxes represent the 25th, 50th, and 75th percentiles. Whiskers infusion was safe and ef- neurotomy is to expose and represent minimum and maximum values excluding outliers beyond 1.5 times the interquartile range. P values are based on Wilcoxon’s fective for the long-term isolate the nerve branches that tests, with blocking on site for combined tests.21 treatment of intractable spasticity. The ﬁrst trial supply the spastic muscle. A ness of oral baclofen may be limited by reported in children was by Albright et complete or partial division is dose-related side effects such as seda- al.28 in 1991, which also demonstrated tion, respiratory depression, confusion, signiﬁcantly reduced spasticity with an then performed. and hallucinations. Baclofen penetration acceptable complication rate. into the central nervous system is also In the clinical setting, it often is dif- limited by the blood–brain barrier. ﬁcult to determine which patients are Ashworth scale is considered a positive Impressive results from intrathecal better suited for SDR and which are bet- response and is seen in approximately administration of baclofen (ITB) were ter for ITB therapy. Two main groups 90% of patients. Escalating doses of 75 ﬁrst demonstrated in adult patients with of children generally have a better out- or 100 micrograms of intrathecal ba- spasticity from spinal cord injury or come if treated with ITB therapy. The clofen can be attempted if the ﬁrst dose multiple sclerosis. A dramatic reduc- ﬁrst group includes those who have a is unsuccessful. tion of tone was achieved with dosages severe spastic quadriparesis, are func- Implantation of a pump to administer that were many orders of magnitude less tionally debilitated, and are completely baclofen continuously can be undertak- than oral or parental doses. Penn et al.26 dependent for care. These children often en after a positive trial. The pump itself, ﬁrst reported a trial of 20 patients in respond well to ITB therapy because a which is roughly the size of a thin hockey 1989 who received baclofen or placebo global reduction in tone can lead to an puck, is implanted into the anterior ab- for three consecutive days followed by improvement in comfort, positioning, dominal wall in either the subcutaneous 360 PEDIATRIC ANNALS 35:5 | MAY 2006 space or in a subfacial location. Flexible tubing runs subcutaneously around the A ﬂank to the lumbar spine and into the Average Ashworth Score subarachnoid space. The tip of the intra- thecal tubing is positioned under ﬂuoro- (± 2 SE) scopic guidance at a spinal cord level as determined by the pattern of spasticity preoperatively (ie, higher placement of the catheter if severe upper extremity spasticity is present). The pump is pro- grammed via a telemetry magnet on the Baseline skin directly over the pump, with the ini- Follow-up Months tial setting typically delivering around 50 micrograms per day. The dose can B be increased as the child recovers from Average Ashworth Score surgery in the hospital, and then in the outpatient setting until the desired goal (± 2 SE) is achieved. The child should be monitored close- ly after an ITB trial or pump placement, as side effects including sedation, hy- potonia, and respiratory depression can Baseline result in rare circumstances. Reﬁlling of Follow-up Months the pump is required every 2 to 6 months, depending on the dose administered, and Figure 4. (A) Graph demonstrating the mean Ashworth scores in the lower extremities at 6-month is done via a percutaneous injection, The intervals after pump implantation. The scores were signiﬁcantly decreased at 1 and 2 years post-im- battery in the pump expires after seven plantation (P < .005). (B) Graph demonstrating the mean Ashworth scores in the upper extremities at 6-month intervals after pump implantation. The scores were decreased signiﬁcantly at 1 and 2 years years. The minimum weight require- post-implantation (P < .005). (SE = standard error.)30 ment for a child to have an ITB pump is approximately 10 kg. months. Lower-extremity and upper-ex- Awaad31 also reported on 29 patients Multiple clinical studies have dem- tremity spasticity decreased signiﬁcantly with cerebral palsy with short-term fol- onstrated that the majority of patients in all patients. The side effects observed low-up (48 months or less) after intra- with ITB therapy have a signiﬁcant de- were mostly drug-related and included thecal baclofen therapy. The outcome crease in spasticity and some functional temporary hypotonia, seizures, somno- measures of spasticity as rated by the improvement.30-33 The multicenter trial lence, and nausea or vomiting. Ashworth scale and the caregiver assis- that resulted in FDA approval was re- In 2003, Albright30 reported a pro- tance scales of the Pediatric Evaluation ported in 2000 by Gilmartin et al.14 This spective, multicenter study of 68 patients of Disability Inventory (PEDI) were im- study assessed the effectiveness of in- with chronic intrathecal baclofen therapy proved in all patients. trathecal baclofen in reducing spasticity who were followed closely for an aver- The signiﬁcant advantage of ITB in cerebral palsy through an open-label age of 70 months. The majority (76%) of therapy is the adjustable and nondestruc- trial of intrathecal baclofen administered these patients were younger than 16 and tive nature of the therapy. The amount of through a chronic implanted pump. Can- willing to participate in long-term sur- drug delivery can be adjusted to meet the didates were ﬁrst screened with random- veillance. Spasticity in both upper and needs of each speciﬁc child. Because no ized, double-blind, intrathecal injections lower extremities decreased signiﬁcantly nervous tissue is destroyed, the effect of of baclofen and placebo. Responders and remained decreased throughout the the therapy is reversible. The disadvan- were deﬁned as those who experienced study period (Figure 4). The dosage of tage, however, is that complications arise an average reduction of one point in the baclofen doubled on average during the in some patients. Patients can be over- lower extremities on the Ashworth Scale. initial 2 years and then remained stable; dosed with baclofen with subsequent Ultimately, 44 patients received chronic there were no signiﬁcant differences with hypotonia and lethargy, which usually therapy and were observed for up to 43 dosage in children of different ages. are managed with supportive care and PEDIATRIC ANNALS 35:5 | MAY 2006 361 adjustments of the pump rate. Catheter 6. Gooch JL, Oberg WA, Grams B, Ward LA, Child Neurol. 2002;44(1):17-25. Walker ML. Care provider assessment of in- 22. McLaughlin JF, Bjornson KF, Astley SJ, et al. migration, disconnection or fractures trathecal baclofen in children. Dev Med Child Selective dorsal rhizotomy: efﬁcacy and safety in can occur, as well as other surgical prob- Neurol. 2004;46(8):548-552. an investigator-masked randomized clinical trial. lems such as seromas, cerebrospinal 7. Ashworth B. 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Zafonte R, Lombard L, Elovic E. Antispastic- thop. 1991;11(4):494-497. ity medications: uses and limitations of enteral 25. Mooney JF 3rd, Millis MB. Spinal deformity tions were catheter disconnection (9%), therapy. Am J Phys Med Rehabil. 2004;83(10 after selective dorsal rhizotomy in patients catheter dislodgement (8%), pump site suppl):S50-S58. with cerebral palsy. Clin Orthop Relat Res. infection (4%), and cerebrospinal ﬂuid in- 11. Koman LA, Mooney JF 3rd, Smith B, Goodman 1999 Jul;(364)48-52. A, Mulvaney T. Management of cerebral palsy 26. Penn RD, Savoy SM, Corcos D, et al. Intra- fection (1%).35 Also, if ITB therapy is dis- with botulinum-A toxin: preliminary investiga- thecal baclofen for severe spinal spasticity. N continued abruptly, baclofen withdrawal tion. J Pediatr Orthop. 1993;13(4):489-495. Engl J Med. 1989;320(23):1517-1521. can occur, leading to rebound spasticity, 12. Gormley ME, Gaebler-Spira D, Delgado MR. 27. Coffey JR, Cahill D, Steers W, et al. 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