Chapter 34 What Is the Best Treatment for Ambulatory Cerebral Palsy?
WHAT IS CEREBRAL PALSY? NEW DEFINITION AND CLASSIFICATION
Cerebral palsy (CP) constitutes one of the most common causes of chronic childhood disability, with rates estimated between 2 and 2.5 per 1000 live births.1 This chapter discusses the evidence for interventions for ambulant children with CP. Any discussion about the effectiveness of interventions in CP must first consider what CP and its associated pathophysiology are, and take into account the heterogeneity and natural history of CP to put definitions of “effectiveness” into perspective.
An international multidisciplinary collaborative effort to arrive at a consensus definition and classification system for CP was begun in 2004.2 This culminated in the Report on the Definition and Classification of Cerebral Palsy, which states that the term “CP describes a group of permanent disorders of the development of movement and posture, causing activity limitation, that are attributed to non-progressive disturbances that occurred in the developing fetal or infant brain. The motor disorders are often accompanied by disturbances of sensation, perception, cognition, communication and behaviour, by epilepsy, and by secondary musculoskeletal problems.”3 The robustness (reliability and validity) of this definition is yet to be established, and it is not the only one in current use, but this report based on collective expert opinion, represents the best effort to date to standardize the definition, inclusion/exclusion criteria, and the characteristics used currently for describing children with CP.
In this report, the international group also proposed a new classification system3 because the traditional classifications of CP based on the movement disorder (spastic, ataxic, or dyskinetic) and/or topographic distribution (hemiplegia, diplegia, and quadriplegia) alone were not reproducible, not reliably prognostic, or adequately descriptive of the heterogeneous population of children with CP. The new classification is based on 4 dimensions:
PATHOPHYSIOLOGY
The hallmark of CP is abnormal muscle tone, of which spasticity is the most common type, accompanied by loss of selective motor control, muscle weakness, and impaired balance.7 Muscles grow in response to the stimulus of stretch derived from normal physical activity. Hypertonia and limited use of muscles because of developmental delay result in dynamic (velocity-dependent) muscle contractures, which become static joint contractures over time as the tight muscles fail to grow proportionately with their skeletal attachments (Level V evidence from animal studies).8 These abnormal forces on the growing skeleton lead to secondary bony deformities and joint instability, and related lever arm dysfunction.9 In children with ambulatory potential, the interaction of joint contractures, muscle weakness, bony deformities, and joint instability at multiple levels affect the quality and efficiency of gait and other aspects of their physical function. This understanding of the pathophysiology of CP is based on Level IV and V evidence.
IMPLICATIONS OF NATURAL HISTORY OF CEREBRAL PALSY ON OUTCOMES EVALUATION
Based on a prospective longitudinal cohort study of 657 children, Level I evidence has been reported that shows that gross motor function improves in children up to the age of 6 or 7 years, albeit with different trajectories for each GMFCS level, but it remains stable after motor development is complete.6 “Improvements” after any interventions in younger children must therefore be placed in the context of expected improvements in gross motor function before the age of 7 years. In contrast, although the primary central nervous system pathology is static, the secondary musculoskeletal pathology and its consequences are known to deteriorate over time in older children. Bell and colleagues10 report deterioration in passive range of motion, and spatiotemporal and kinematic parameters on gait analyses an average of 4.5 years apart in a group of 28 ambulatory children with CP who had not undergone any surgery during this interval.10 Johnson and coworkers11 found similar rates of deterioration in gait over a 32-month period in 18 ambulatory children (4–18 years old) regardless of age or history of prior surgery. Despite their small sample sizes, both these longitudinal case series (Level IV evidence) suggest that effectiveness of surgical interventions for this population must be interpreted in the context of natural deterioration of gait with growth. Consequently, preintervention versus postintervention comparisons in uncontrolled case series may underestimate the outcomes of these interventions in the short term.12 However, short-term outcomes are also less meaningful because the growing child is at risk for recurrent deformity and gradual loss of mobility over the long term, because the primary central nervous system pathology remains unaffected by the intervention. Mobility in adulthood may also deteriorate over time (Level IV evidence).13–15 These issues have implications both on the optimal age at which the surgical interventions should be performed and the timing of outcome assessments.
GOALS OF TREATMENT AND OUTCOMES TO CONSIDER
The goals of treatment of ambulatory children with CP are to preserve or improve present and future gait efficiency and physical function, and secondarily to improve the appearance of gait.16 The treatment principles to accomplish these goals are: (1) prevention of joint contractures and skeletal deformities by muscle stretching, spasticity reduction, and muscle strengthening; and (2) correction of significant contractures and bony deformities when these have already occurred. Evaluating the effectiveness of interventions to achieve these goals requires defining the outcomes of interest and the longevity of these outcomes.17,18
The American Academy for Cerebral Palsy and Developmental Medicine (AACPDM) advocates the use of a two-part conceptual framework to evaluate the effectiveness of interventions.19,20 The framework analyzes and categorizes treatment outcomes according to the components of the International Classification of Functioning, Disability and Health (ICF),21 and judges the strength of the evidence according to the study design and rigor in the conduct of the study. The ICF model has two parts, each with two components (Table 34-1).
TABLE 34-1 International Classification of Functioning, Disability, and Health Model
| COMPONENTS | DEFINITION AND EXAMPLES |
|---|---|
| Part I: Functioning & Disability | |
A common, but often untested assumption is that treatment at one level (e.g., body structure and function: knee flexion contracture) may positively affect another level (e.g., activity and participation: by permitting independent walking over longer distances). Similarly, interventions do not always have simple effects on a single dimension. For example, powered mobility may increase activities by providing an alternative means of efficient locomotion, which may also increase participation by allowing a student to be independent and move around the school faster and with less effort, but may have negative effects in the body structure and function such as increased knee flexion contractures.22 A multicenter cross-sectional study found at best a fair correlation between measures of spasticity or range of motion (body structure and function) and measures of gross motor function or physical function.23
INTERVENTION STRATEGIES FOR AMBULATORY CEREBRAL PALSY
A number of complementary strategies are used sequentially or in combination, including physical therapy, orthotics (braces), and serial casting to simulate the stretch that would normally be derived from usual physical activity, to stimulate muscle growth. These strategies are often accompanied by measures to reduce muscle tone by pharmacologic (botulinum toxin type A [BTX-A], phenol) or neurosurgical methods (selective dorsal rhizotomy [SDR], intrathecal baclofen). These are believed to facilitate the stretch from therapy and serial casting, and to improve tolerance of brace wear, which, in turn, may prevent or delay the onset of static contractures and bony deformities.24,25 The musculoskeletal changes, collectively referred to as “lever arm disease” are best addressed with orthopedic surgery.9
EVIDENCE FOR EFFECTIVENESS OF SPASTICITY REDUCTION METHODS
Botulinum Toxin A
A systematic review published in the Cochrane database in 2000 could not find sufficient evidence to support or refute the use of BTX-A in the treatment of lower-limb spasticity in children with CP.26 Systematic reviews of more recent randomized trials (Level 1 evidence) confirm that injection of BTX-A compared with placebo27–30 does reduce calf (equinus) spasticity, increase ankle dorsiflexion, and improve gait pattern in the short term.31,32 When compared with serial casting, two small randomized clinical trials (RCTs) with only 10 patients in each arm (Level II evidence) showed that BTX-A injections were as efficacious as serial casting in the management of dynamic equinus.33,34 The BTX-A group had a more sustained response than casting, although median time to reintervention was similar in both groups.33 This evidence was contradicted by a subsequent small RCT of 23 patients randomized to receive either serial casting alone or serial casting with BTX-A, which showed equivalent reduction in spasticity and increased dorsiflexion at 3 months in both groups, but more sustained benefits in the cast alone group at 12 months.35 However, in another small double-blind RCT, 39 patients were randomized to receive BTX-A alone, placebo injection plus casting, or BTX-A plus casting. The BTX-A injection group did not show any significant change, whereas the two groups that were casted with placebo injection or BTX-A showed significant but equivalent improvements in spasticity reduction, passive range of motion, and ankle kinematics at 12 months.36
In summary, BTX-A injections are superior to placebo injections in reducing calf muscle spasticity and increasing ankle dorsiflexion in the short term, but show only equivalent efficacy in the short term when compared with serial casting, with mixed evidence regarding the combination of serial casting plus BTX-A. Limited evidence exists in the literature to support the widely held belief that the reduction in spasticity brought on by BTX-A potentiates the effect of therapy interventions to reduce the mechanical aspects of the hypertonicity,24 and even less evidence that these effects translate into measurable functional benefits in terms of activities and participation.
In a systematic review to evaluate the evidence for the effectiveness of therapy (including serial casting) after BTX-A injections, Lannin and colleagues37 found only two studies with control groups that compared BTX-A alone with botulinum toxin plus some form of therapy. In a small prospective series of 25 children (Level IV evidence), Boyd and coworkers38 found that a short period of casting improves passive range of motion and ankle kinetics, whereas Desloovere and coauthors39 found that it makes no difference if such casting is provided immediately before or after BTX-A injections in a small randomized trial of 34 children (Level II evidence). In a multicenter clinical trial in the Netherlands, 46 children were randomized to receive multilevel BTX-A followed by comprehensive rehabilitation or just usual physiotherapy (PT). The BTX-A plus comprehensive rehabilitation group experienced significantly greater improvements in the gross motor function measure (GMFM) outcome measure at 24 weeks (3.5 points better than usual physical therapy group). This effect, although clinically significant, is modest at best, and this study cannot separate the relative contributions of BTX-A from those of the cointervention of comprehensive rehabilitation to the improved outcome.40
Although a retrospective cohort study of 424 patients (Level III evidence) concluded that a program of serial multilevel Botox injections might delay the need for, and reduce the frequency of, orthopedic surgery,41 this evidence is undermined by the unknown comparability of the treatment cohorts at baseline, the different periods that the cohorts were treated, and the possibility of bias by indication. Furthermore, the long-term effects or benefits of BTX-A in terms of improved muscle growth, mobility, and function remain unknown.42
Selective Dorsal Rhizotomy
Three published randomized trials have evaluated the efficacy of selective dorsal rhizotomy followed by physiotherapy (SDR + PT) compared with PT alone.43–45 All 3 trials showed that SDR + PT consistently reduced spasticity, but only in the Toronto (n = 24) and Vancouver (n = 30) trials was there a significantly greater improvement in function as measured by the GMFM in the SDR + PT groups at 1 year. In the Seattle trial (n = 38), there was no demonstrable difference in functional outcomes (GMFM) between the 2 groups either at 12 or 24 months, with both groups demonstrating equivalent functional gains. A possible explanation may be that patients in the PT group in the Seattle trial received an intensive and prolonged course of PT, far more than their counterparts in the other two trials, and the rhizotomies performed in Seattle involved transaction of significantly fewer rootlets than at the other 2 locations, which could also explain the smaller gains demonstrated by the SDR + PT groups in the Seattle trial. A meta-analysis of these 3 randomized trials (Level 1 evidence) confirmed that for children between 4 and 8 years of age with spastic CP, SDR + PT does produce a clinically significant reduction in spasticity at 12 months and a statistically significant but relatively small functional advantage of 4 percentage points on the GMFM when compared with PT alone.46 In the multivariate analysis, a positive association was found between the percentage of rootlets transected and the magnitude of functional improvement. Despite the effectiveness of SDR in the short term, the question remains whether these small benefits are worth the time, effort, and expense involved. Only limited evidence (Levels III and IV) exists that SDR reduces the need for or amount of subsequent orthopedic surgery,47–49 and the long-term effects and benefits of SDR have yet to be elucidated.
EVIDENCE FOR MULTILEVEL ORTHOPEDIC SURGERY
Established musculoskeletal problems are thought to be best addressed with simultaneous (single-event) multilevel orthopedic surgery (SEMLS) including tendon lengthening or transfers and corrective osteotomies based on small uncontrolled case series50,51 and expert opinion (Level IV and V evidence). Addressing all deformities simultaneously avoids the “birthday syndrome” of staged isolated procedures16 and limits the interventions to one hospitalization and one period of rehabilitation (Level V evidence). However, to date, no comparative studies have tested the superiority of this approach, leaving room for some debate. Some surgeons recommend (Level V evidence) early surgical interventions during childhood development with the expectation that this will enhance function and allow further improvement of motor skills, with further surgery as needed when the child is older. 52 This approach also uses multilevel procedures as needed and has been referred to as Staged Multilevel Interventions in the Lower Extremity (SMILE). There is some weak Level IV evidence from small case series that children with spastic diplegia who underwent staged orthopedic procedures had unpredictable results.53 In contrast, there is little evidence that the single-event multilevel surgery performed at the optimal (older) age eliminates the need for additional surgery in the future.
Outcomes of Multilevel Orthopedic Surgery Compared with Natural History
Only 1 retrospective cohort study (Level III evidence) compares the short-term outcomes in a small group of ambulatory children with spastic diplegia treated with multilevel surgery (n = 12) with those of a control group of comparable children (n = 12) who were recommended but did not undergo similar types of multilevel surgery.12 Effects of treatment were derived from change in gait analyses between the baseline assessment and 12 months later. Gait of children in the control group deteriorated between analyses, whereas for the treatment group, parents’ perceived walking distance and reliance on assist devices improved. Whether these benefits were a consequence of the multilevel surgery or the intensive postoperative PT (or both) that the operated patients received is unknowable from this study, and whether these benefits will last over the long term remains a concern in light of some Level IV evidence from longitudinal case series that mobility will deteriorate in growing children even after surgery.11 Few published studies evaluate the long-term effects of multilevel orthopedic surgery at skeletal maturity, let alone into adulthood.18
Outcomes of Multilevel Orthopedic Surgery Compared with Other Interventions
In a prospective cohort study of ambulant children with spastic diplegia who underwent either SDR or multilevel orthopedic surgery as their initial surgical procedure, children who underwent SDR (n = 16) demonstrated improvements in 3 of 5 dimensions, as well as the total score of the GMFM, but more than 60% of these patients experienced a reduction in gait velocity. Those who underwent orthopedic surgery (n = 14) had more predictable improvements in spatiotemporal gait parameters, although their improvements in the GMFM was limited to only 1 dimension (walking, running, and jumping) and the total score.54 This study comprised 2 separate treatment cohorts studied prospectively that had the same preoperative and postoperative measures, allowing for the comparison at about 12 months after surgery, rather than a randomized (or nonrandomized trial) of similar patients (Level II evidence). In another prospective cohort study of children with spastic diplegia with a mean age of 73 months, 18 children who underwent SDR were compared with 7 who underwent orthopedic surgery (Level II evidence). Significant improvements were seen in passive range of motion, muscle tone, gait kinematics, and oxygen cost in both groups 2 years after surgery. 48 In both of these studies, the unknown comparability of the groups at baseline and the different indications for choosing SDR or orthopedic surgery bias any inferences. Furthermore, the 2 interventions should be seen as complementary because they address different facets of the problem (spasticity in the case of SDR and fixed contractures, and/or bony deformities in the case of multilevel orthopedic surgery), rather than as competing alternatives to manage the ambulant child with spastic CP.
Evidence for Specific Orthopedic Procedures and Techniques
The most common soft-tissue procedures include intramuscular lengthening of the psoas over the pelvic brim,55–57 fractional lengthening of the medial hamstrings,50,55,58–61 transfer of the rectus femoris for a stiff knee gait,62–66 and recession of the gastrocnemius.67,68 Open lengthening of the hip adductors, iliopsoas tenotomy, lengthening of the lateral hamstrings,61 and tendo-Achilles lengthening69 are rarely required and may lead to overcorrection and weakness, especially in bilateral involvement.70 Significant equinovalgus/planovalgus deformities of the feet can be corrected with calcaneal lengthening,71 sometimes combined with subtalar arthrodesis to prevent recurrence. Equinovarus deformities can be managed with split tibialis posterior tendon transfers for flexible deformities72 and split tibialis anterior tendon transfer combined with intramuscular lengthening of the tibialis posterior and tendo-Achilles for stiffer deformities in older children.73,74 Severe torsional deformities can be addressed with derotational osteotomies of the femur either distally or proximally,75–77 and supramalleolar derotational osteotomies of the tibia and fibula.78
The quality of evidence in support of these specific interventions to improve gait in ambulatory children with CP is weak and based almost entirely on uncontrolled case series (Level IV evidence). This is equally true of studies evaluating the efficacy of multilevel orthopedic surgery as a whole. These studies are typically small, retrospective, uncontrolled case series looking at preintervention and postintervention comparisons that demonstrate some improvements in the short term in outcomes limited to the level of body structures and body functions, such as range of motion, spatiotemporal gait parameters, and kinematic or kinetic improvements on gait analysis.18,59,79–81 The clinical significance of these findings is less clear, with only a few case series (Level IV evidence) reporting benefits in some functional outcomes at the level of activities and participation.80–84
A few retrospective, case–control or cohort studies (Level III evidence) compare different surgical techniques, but few prospective clinical trials compare the effectiveness of these procedures. In a case–control study, rectus femoris transfer (n = 98) has been reported to be superior to distal rectus release (n = 31), especially for children with less than 80% knee range of motion.63 One case–control study showed little difference in functional outcomes or complication rates between proximal (n = 27) and distal femoral (n = 51) derotational osteotomies.77 In a prospective cohort study of 28 patients with spastic diplegia and intoed gait, there was no difference in the gait outcomes between the proximal and distal femoral derotational osteotomies, but the distal osteotomies were reportedly faster with significantly lower blood loss (Level II evidence).76
In a systematic review of different interventions to improve gait, these interventions did have a statistically significant effect on the spatiotemporal parameters of gait.85 This was true for specific orthopedic procedures as well, when the analysis was stratified based on the type of intervention. However, the authors were unable to make any clinical recommendations about relative efficacy of different interventions. The majority of the individual studies included were Level III or IV studies with sample sizes smaller than necessary to detect the effect sizes they found from the meta-analysis. Nearly every study failed to categorize patients by (and therefore adjust for) severity, age, or type of CP, and did not take into account the effect of cointerventions that are inevitable in multilevel surgery and are likely to have an impact on the outcomes.
EVIDENCE FOR USE OF GAIT ANALYSIS FOR SURGICAL DECISION MAKING BEFORE MULTILEVEL ORTHOPEDIC SURGERY
Little consensus exists about the indications or choice of which procedures to perform during multilevel surgery.86,87 For ambulatory patients, gait analysis has been recommended to guide surgical decision making, but it remains an area of much controversy among pediatric orthopedic surgeons.88–90 The basic premise of gait analysis is that gait data generated in a motion laboratory provide insight beyond what is derivable from observational analysis alone, and that it has the potential to influence or alter treatment decisions for at least some patients whose outcomes presumably would have been worse had they had surgery based on decisions made by observational analysis alone.
Does Gait Analysis Alter Decision Making?
Level IV evidence has been reported that gait analysis alters surgical decision making for patients with CP. In 3 separate case series, treatment recommendations based on observation of gait changed with the addition of gait analysis data in 52%, 93%, and 40% of the cases.91–93 However, in all 3 studies, the investigators were not blinded to their decisions based on observation alone. We also do not know whether these decisions would have been consistent if retested at a later time (reproducibility). In the Hartford study, all patients reportedly underwent treatment based on the gait analysis recommendations; therefore, in the absence of control subjects, we do not know whether implementing these recommendations did, indeed, result in different, let alone better, outcomes.91 The authors conclude that because in their series gait analysis data led to an overall reduction in the number of procedures recommended, this would be associated with a reduction in cost of surgery. However, we do not know whether the treatment decisions based on gait analysis were the ones that were, in fact, carried out. Furthermore, conclusions regarding potential cost reductions are somewhat speculative because a valid health economic evaluation was not performed. The 2 other studies also demonstrated that decisions were altered by the addition of gait analysis data, but once again with little evidence that these altered decisions were either reproducible or better than the original decisions made by observation alone.92,93
Does the Use of Gait Analysis for Surgical Decision Making Result in Better Functional Outcomes after Multilevel Orthopedic Surgery?
A systematic review of the literature on the use of gait analysis in children with walking disorders reported that there was little published evidence that outcomes of surgery based on gait analysis are any better than outcomes of surgery based on observational analysis alone.94 One case–control study (Level III evidence) attempts to answer this question. Lee and colleagues95 retrospectively selected 23 patients with ambulatory CP who had complete preoperative and postoperative gait analysis available out of 100 patients who had been evaluated in their gait laboratory over a 5-year period.95 Eight of these 23 children underwent surgery based on the visual analysis alone rather than the recommendations based on gait analysis. The authors provide no information as to why these 8 patients underwent operations different from what was recommended or whether their surgeons had had access to the gait studies. The outcomes of these 8 children were compared with those of the 15 children who were treated according to the recommendations based on preoperative gait analysis. Of the 7 children who reportedly did not improve based on the postoperative gait analysis data as the outcome measure, 5 of these 7 children belonged to the control group that received treatment based on clinical (visual) analysis alone. Thirteen of 15 children showed improved gait outcomes in the gait analysis group compared with only 3 of 8 in the control group. The authors conclude that gait analysis was responsible for the difference in outcomes between the 2 groups. However, the small numbers of patients, the absence of information on the comparability of the 2 groups at baseline, the short follow-up, and the absence of any functional outcomes undermine any conclusions regarding the necessity for, or the benefits of, preoperative gait analysis.
Other retrospective case series (Level IV studies) of children with ambulatory CP undergoing multilevel orthopedic surgery, in which patients underwent preoperative and postoperative gait analyses, have documented postoperative improvement in outcomes.59,82, 96 However, in the absence of any control subjects, it is not possible to conclude with any confidence that these improvements are attributable to the use of gait analysis either.
Molenaers and coauthors41 suggest that gait analysis delays the first orthopedic procedures in children with CP based on a retrospective review of 424 children with ambulatory CP treated at one center from 1985 to 2001. Three historical cohorts were compared (Level III evidence): group 1 (1985–1989), group 2 (1996–1997), and group 3 (2000–2001). These groups were separated by the introduction of gait analysis in 1990 and the addition of BTX-A in the early treatment of these children in 1996. Children in group 1 who did not have the benefit of gait analysis or botulinum toxin underwent surgery significantly earlier than those in group 2 who had the benefit of gait analysis. There was also a significant decrease in the frequency of surgery for groups 3 and 2 compared with group 1. The authors acknowledge the limitations of such a study and are careful to qualify their conclusions. The association between the introduction of gait analysis and the delay of surgery could be attributable to change in philosophy with the times rather than the introduction of gait analysis. Furthermore, delay of surgery is at best a proxy for, and not necessarily representative of, improved outcomes.
Chang and researchers97 evaluated retrospectively 20 children with ambulatory CP who were recommended orthopedic surgery treatment after undergoing gait analysis. For reasons not explained, 10 children did not follow through with these recommendations and underwent unspecified alternative nonoperative treatments, whereas the other 10 completed the surgical procedures recommended. The surgical group experienced “a higher percentage” of positive (44%) gait outcomes compared with the group who did not follow the gait analysis-based surgical recommendations (26%). The authors conclude that “gait performance can be significantly improved when gait analysis is used to determine the appropriate surgical intervention.”97 However, little information is available about the comparability of the 2 groups at baseline other than the similarity of the surgical recommendations based on gait analysis. The “outcomes” are based on desired or expected changes in the gait kinematics. This definition is unsatisfactory because all changes are arbitrarily treated as equal. We also have no knowledge of how these changes relate to the outcome of real interest, which is physical function. The only conclusion is that, in this series, patients treated with surgery responded better based on the authors’ definition of gait outcomes than patients treated by nonoperative methods (Level III). The actual contribution of gait analysis to these outcomes is speculative. For gait analysis to be effective in this role, it needs to be shown to alter decision making in a reproducible or consistent way.90
Effect of Variability in Gait Analysis
Many sources of variability stem from gait analysis, including patients themselves,98,99 and between gait laboratories100 because of variation in equipment, marker placement, and lack of standardization. After implementation of a standardized protocol in gait laboratories in the Shriner’s system in North America, there was only a moderate decrease in the variability across the 12 sites, which the authors conclude must be improved on before the data between laboratories can be considered comparable.101 These technical problems are likely to be solved with technical solutions, which will not, however, address the issue of variability of interpretation and treatment recommendations.90
Reproducibility of Gait Analysis Interpretation and Surgical Recommendations
When the same gait analysis data were examined by gait analysis experts from 6 different institutions in the United States, there was only slight-to-moderate agreement in the list of problems (Kappa values: 0.14–0.46) generated by the experts.102 Agreement about specific surgical recommendations was similarly poor, except for hamstring lengthening (Kappa value: 0.64). The authors conclude that, although gait analysis data are themselves objective, there is subjectivity in interpretation even among recognized experts, with diagnoses and treatment recommendations seemingly influenced by the institution at which the interpretation was performed.102 However, the authors did not report the inter-rater reliability at the institutional level, which would have provided some support to the latter conclusion.
Variability was present in the kinematic data generated in 4 different motion laboratories that tested the same 11 patients.100 Although the clinical significance of some of this variability has been challenged, the treatment recommendations generated from these data were widely different across the 4 centers for 9 of the 11 patients. Perhaps such variability might not have been demonstrated had the patients been tested in other gait centers, as was implied in the accompanying editorial,103 but evidence to support this contention remains elusive.
In the presence of significant variability, the data cannot be used with confidence to influence decision making. Variability in the interpretation of gait data reflects the prevailing uncertainty (or controversies) about the causes and/or significance of specific findings, and will be resolved only with ongoing clinical research and experience using gait analysis.104 Similarly, variability in treatment recommendations based on the same gait data also reflects differences of opinion about best strategies to deal with specific problems, which, in turn, can be definitively resolved only with comparative clinical trials. Neither the variability in interpretation nor the variability in surgical recommendations is the fault of gait analysis per se, but as long as such significant variability exists, the recommendation that gait analysis is essential for preoperative decision making before multilevel orthopedic surgery is currently not supported by the literature.90 Consequently, there is wide variation across North America in the rates of utilization of gait analysis for surgical decision making in the management of children with ambulatory CP.105 It is not clear whether there is corresponding variation in functional outcomes of children receiving multilevel orthopedic surgery in different centers in North America, and if so, whether these differences are attributable to the use of gait analysis or other factors, such as surgical skill and experience, or the quality of the postoperative rehabilitation.
CONCLUSION
A paucity of high-level evidence exists of the efficacy of orthopedic procedures used for children with CP. Moreover, the methodologic rigor of these studies even within their level of study design is low. A lack of consensus has been shown on the indications for these specific procedures. Although there is some evidence (mostly Level IV) that multilevel orthopedic surgery may benefit the gait of ambulatory children with CP in the short term, especially when compared with the natural history (Level III evidence), there is less evidence that these short-term benefits translate into any meaningful improvements in the dimensions of activities and participation, or that these benefits are long lasting, let alone permanent. A growing recognition exists for the need to improve and expand the evidence base for the orthopedic management of children with chronic developmental disabilities.104,106 Further studies are needed to define the long-term outcomes in these children to improve our understanding of the indications for and the effects of multilevel surgery for this population.12 Although RCTs are desirable, these are not immediately forthcoming because of the high cost, multiplicity of interventions, need for long-term outcomes, and problems of recruitment and retention associated with the large numbers of patients from multiple centers needed to participate, which make such trials difficult to conduct.106 Alternatives to RCTs are beginning to emerge including pragmatic or practical clinical trials107 and Clinical Practice Improvement, which uses a large-scale, prospective, observational design incorporating comprehensive review of key patient characteristics, all treatment and care processes and outcomes,108 and multivariate analyses to account for heterogeneity of patient populations. Even the quality of lower-level study designs can be greatly improved by following established guidelines.109 Table 34-2 provides a summary of recommendations.
| STATEMENT | LEVEL OF EVIDENCE/GRADE OF RECOMMENDATION | REFERENCES |
|---|---|---|
43–45
BTX-A, botulinum toxin type A; CP, cerebral palsy; PT, physiotherapy; SDR, selective dorsal rhizotomy; SEMLS, single-event multilevel orthopedic surgery.
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