Spasticity and strength changes as a function of selective dorsal rhizotomy

Comparing short-term outcomes between conus medullaris and cauda equina surgical techniques of selective dorsal rhizotomy

AIM

To compare short-term outcomes between conus medullaris (conus) and cauda equina (cauda) selective dorsal rhizotomy (SDR) techniques in children with spastic cerebral palsy.

METHOD

This was a retrospective review of SDR at a single center from 2013 to 2017. Gait and functional outcome measures were assessed at no more than 18 months pre-SDR (baseline) and 8 to 36 months post-SDR (follow-up). Transient complications during inpatient stay were quantified.

RESULTS

In total, 21 and 59 children underwent conus and cauda SDR respectively. Ashworth Scale scores were nearly normalized at follow-up. Most physical examination and functional measures exhibited similar baseline to follow-up responses for both groups. From baseline to follow-up, sagittal plane knee kinematics for both groups significantly improved (p<0.01) by 11° at initial contact, 9° to 10° in stance phase, and 4° in swing phase. Sagittal plane ankle kinematics improved more for the cauda group than the conus group in both stance phase (10° vs 2°, p<0.01) and swing phase (13° vs 3°, p<0.01). Post-surgical complications were similar between groups.

INTERPRETATION

Conus and cauda SDR techniques resulted in similar short-term outcomes except in ankle kinematics at follow-up. The cauda group exhibited a large improvement towards dorsiflexion, while there was residual equinus in the conus group despite Ashworth Scale scores normalizing equally in both groups.

WHAT THIS PAPER ADDS

Conus and cauda selective dorsal rhizotomy (SDR) resulted in mostly similar short-term gait and functional outcomes. Conus SDR resulted in residual equinus dynamically, despite normalized spasticity measures. Post-surgical complications were mostly similar between SDR techniques.

The selective dorsal rhizotomy technique for spasticity in 2020: a review

This review looks at the advances in the surgical technique, selective dorsal rhizotomy, used for the management of spasticity in children.

Intraoperative neurophysiological monitoring in selective dorsal rhizotomy (SDR)

For decades, intraoperative neurophysiological monitoring (IONM) has been used to guide selective dorsal rhizotomy (SDR) for the treatment of spastic cerebral palsy (CP). Electromyography (EMG) interpretation methods, which are the core of IONM, have never been fully discussed and addressed, and their importance and necessity in SDR have been questioned for years. However, outcomes of CP patients who have undergone IONM-guided SDR have been favorable, and surgery-related complications are extremely minimal. In this paper, we review the history of evolving EMG interpretation methods as well as their neuroelectrophysiological basis.

Selective dorsal rhizotomy improves muscle forces during walking in children with spastic cerebral palsy

BACKGROUND

Selective dorsal rhizotomy aims to reduce spasticity in children with cerebral palsy. Early investigations indicated postoperative weakness, whereas more recent studies showed that selective dorsal rhizotomy either does not change or improves muscle strength. All previous studies assessed muscle strength in a static position, which did not represent the walking situation. The aim of this study was to analyze the influence of selective dorsal rhizotomy on muscle forces during gait.

METHODS

Motion capture data of 25 children with spastic cerebral palsy and 10 typically developing participants were collected. A musculoskeletal OpenSim model was used to calculate joint kinematics, joint kinetics and muscle forces during gait. Static optimization and an electromyography-informed approach to calculate muscle forces were compared. A Muscle-Force-Profile was introduced and used to compare the muscle forces during walking before and after a selective dorsal rhizotomy.

FINDINGS

Independent of the approach used (electromyography-informed versus static optimization), selective dorsal rhizotomy significantly normalized forces in spastic muscles during walking and did not reduce the contribution of non-spastic muscles.

INTERPRETATION

This study showed that selective dorsal rhizotomy improves dynamic muscle forces in children with cerebral palsy and leads to less gait pathology, as shown in the improvement in joint kinematics and joint kinetics. Individual muscle force analyses using the Muscle-Force-Profile extend standard joint kinematics and joint moment analyses, which might improve clinical-decision making in children with cerebral palsy in the future. The reference data of our participants and MATLAB code for the Muscle-Force-Profile are publicly available on simtk.org/projects/muscleprofile.

Selective dorsal rhizotomy: A multidisciplinary approach to treating spastic diplegia

Background:

Spasticity is a motor disorder that interferes with mobility and affects the quality of life. Different approaches have been utilized to address patients with spastic diplegia, among which is selective dorsal rhizotomy (SDR). Although SDR has been shown to be efficacious in treating spastic patients, many neurologists and neurosurgeons are not well aware of the procedure, its indications, and expected outcomes due to the limited number of centers performing this procedure.

Objectives:

The aim of this study is to describe the collaborative multidisciplinary approach between neurosurgeons, neurophysiologists, and physiotherapists in performing SDR. In addition, we delineate three illustrative cases in which SDR was performed in our patients.

Materials and Methods:

A retrospective review and analysis of the clinical records of our three patients who underwent SDR was conducted and reported. Patients’ outcomes were evaluated and compared to preoperative measurements based on clinical examination of power, tone (Ashworth scale), gait, and range of motion, as well as subjective functional assessment, gross motor function classification system, and gross motor function measure with follow-up at 6, 12, and 24 months postoperatively. A detailed description of our neurosurgical technique in performing SDR in collaboration with neurophysiology and physiotherapy monitoring is provided.

Results:

The three patients who underwent SDR using our multidisciplinary approach improved both functionally and objectively after the procedure. No intraoperative or postoperative complications were encountered. All patients were doing well over a long postoperative follow-up period.

Conclusion:

A multidisciplinary approach to treating spastic diplegia with SDR can provide good short-term and long-term outcomes in select patients suffering from spastic diplegia.

Spasticity secondary to Leigh syndrome managed with selective dorsal rhizotomy: a case report

PURPOSE

Selective dorsal rhizotomy (SDR) is a surgical technique used to treat spasticity in children secondary to cerebral palsy (CP).

METHOD

We report, to the best of our knowledge for the first time, the case of a child who underwent SDR for the management of spasticity secondary to Leigh syndrome.

RESULT

SDR resulted in excellent functional outcome with significant improvement in spasticity. This result contributes to the mounting evidence that SDR could be used to alleviate spasticity secondary not only to CP but also to other pathologies as well.

Infra-Conus Single-Level Laminectomy for Selective Dorsal Rhizotomy: Technical Advance

BACKGROUND/AIMS

Selective dorsal rhizotomy for spastic cerebral palsy is an effective and well-validated surgical approach. Multiple techniques have been described in the past including multiple laminectomies and a single-level laminectomy at the level of the conus. There is considerable technical challenge involved with a single-level laminectomy approach.

METHODS

We report here a modification of the single-level laminectomy that selectively analyzes each individual nerve root with electromyography to separate dorsal and ventral nerve roots through comparison of stimulus responses.

RESULTS

In 18 children with cerebral palsy who underwent this operation there was a mean improvement in the Modified Ashworth Scale of 2.0 with no reported incidence of muscle weakness, sensory loss, or neurogenic bladder.

CONCLUSION

This approach allows for a modification of selective dorsal rhizotomy through a single-level laminectomy and tailors the selection of nerve root sectioning to the individual patient of interest while still maintaining its effectiveness.

Functional outcomes of childhood dorsal rhizotomy in adults and adolescents with cerebral palsy

OBJECT

In this descriptive study the authors evaluated medical outcomes, interventions, satisfaction with life, and subjective impressions about selective dorsal rhizotomy (SDR) in older adolescents and adults who had undergone the procedure as children.

METHODS

A survey was administered to older adolescents (16-20 years old) and adults with CP who had undergone SDR between 1986 and 2000 at two academic centers. The patients or their caregivers participated in telephone or clinic interviews. Subjective impressions about the SDR and a history of post-SDR medical interventions were obtained. Current functional status, history and ratings of pain, educational achievement, living situation, and subjective health status were also recorded. The Diener Satisfaction with Life Scale (SWLS) was administered.

RESULTS

Eighty-eight participants, mean age 25.6 ± 4.8 years (mean ± standard deviation), were interviewed at a mean of 19.6 ± 3.0 years after surgery. The distribution of current reported Gross Motor Function Classification System levels was as follows: I, 7%; II, 18%; III, 23%; IV, 36%; and V, 16%. Moreover, 56% of respondents were living with parents and 25% were living alone. Thirty-five percent were employed, and 39% were still in school. The mean overall SWLS score was 26.0 ± 7.3, indicating a high level of satisfaction with life. According to 65% of the patients, the SDR was helpful; 31% were uncertain about the procedure's efficacy. Sixty-five percent would recommend the procedure to others. Fifty-eight percent reported excellent to very good health. Forty-four percent reported pain in the past week. Fifty-one percent reported chronic back pain in general. Logistic regression analysis suggested that an increased satisfaction with life was a predictor (p = 0.01) of an affirmative response to the question about recommending the procedure to others and that better overall health showed a trend toward being such a predictor (p = 0.08). Additional interventions were frequently performed after the SDR. Seventy-four percent of participants underwent orthopedic surgery. Thirty-eight percent were currently taking oral medications for tone, and 53% had received botulinum toxin injections for spasticity treatment. Thirteen patients (15%) had an intrathecal baclofen pump placed.

CONCLUSIONS

The majority of adults who had undergone SDR as children would recommend the procedure to others. Very few reported negative impressions of the procedure. Levels of satisfaction with life were generally high. Pain prevalence was similar to what has been reported in the literature for adults with cerebral palsy. Despite the SDR, further interventions, both surgical and nonsurgical, were used in the majority of patients.

Knee muscle strength at varying angular velocities and associations with gross motor function in ambulatory children with cerebral palsy

The aim of this study was to evaluate the relationships of muscle strength at different angular velocities and gross motor functions in ambulatory children with cerebral palsy (CP). This study included 33 ambulatory children with spastic CP aged 6-15 years and 15 children with normal development. Children with CP were categorized into level I (n=17) or level II (n=16) according to Gross Motor Function Classification System (GMFCS) levels. All children underwent curl-up test and isokinetic tests of the knee extensor and flexor muscle. Children with CP underwent the gross motor function assessments, including the Gross Motor Function Measure (GMFM-66) and the gross motor subtests of Bruininks-Oseretsky Test of Motor Proficiency (BOTMP). The hamstring-quadriceps ratio (HQ ratio) was calculated as 100%×(isokinetic peak torque of hamstring (knee flexor)/isokinetic peak torque of quadriceps (knee extensor)). Children with GMFCS level II had lower BOTMP and GMFM-66 scores, curl-up scores, HQ ratio, and knee muscle strength, especially knee flexor, compared to those with GMFCS level I. The regression analysis showed that knee flexor torques at 60 and 90°/s are mainly related to balance (r(2)=0.167, p=0.011) and strength (r(2)=0.243, p=0.002) while knee flexor torques at 120°/s mainly contribute to running speed and agility (r(2)=0.372, p<0.001). These findings suggest that children with CP had knee strength deficits, especially knee flexor. Postural muscle (knee flexor) strength dominated gross motor function than antigravity muscle strength (knee extensor). The knee flexor strength at different angular velocities was associated with various gross motor tasks. The HQ ratio may be used as a potential biomarker to probe the therapeutic effectiveness for muscle strengthening in these children. These data may allow clinician for formulating effective muscle strengthening strategies for these children.

The pathophysiological basis of weakness in children with cerebral palsy

PURPOSE

To examine the evidence concerning the neurologic and muscular pathophysiology that contributes to clinically observed weakness in children and young people with cerebral palsy (CP).

METHOD

Literature concerning the neural or muscular changes in subjects with CP was found by searching 6 databases plus supplementary searching.

RESULTS

A final set of 51 articles was identified by 2 independent reviewers.

SUMMARY OF KEY POINTS

Muscle weakness is due to reduced central drive, possible abnormal neural maturation, insufficient and disorganized motor recruitment, impaired voluntary control, impaired reciprocal inhibition, altered setting of muscle spindles, and reinforcement of abnormal neural circuits. Muscle tissue is altered, with selective atrophy of fast fibers and altered myosin expression, changes in fiber length and cross-sectional area, changes in the length-tension curve, reduced elasticity, and impoverished muscle tissue development.

CONCLUSION

Children with CP are weak because of both neurologic and muscular changes.

Normalizing lower extremity strength data for children, adolescents, and young adults with cerebral palsy

The traditional method for normalizing quantitative strength data is to divide force or torque by body mass. We have previously shown that this method is not appropriate for able-bodied children and young adults and that normalization using allometric scaling is more effective. The purpose of the current study was to evaluate the effectiveness of applying existing normalization equations for lower extremity strength to children, adolescents, and young adults with cerebral palsy (CP) and, if appropriate, to develop CP-specific normalization equations using allometric scaling. We measured the maximum torque generated during hip abduction/adduction, knee extension/flexion, and ankle dorsiflexion/plantar flexion in 96 subjects with spastic diplegia CP ages 4-23 years. Traditional mass normalization (Torque/Mass1.0) and allometric scaling equations from children without disability (Torque/Mass1.6 for hip and knee; Torque/Mass1.4 for ankle) were not effective in eliminating the influence of body mass. Normalization using CP-specific allometric scaling equations was effective using both muscle-specific and common (Torque/Mass0.8 for ankle plantar flexors; Torque/Mass1.4 for all others) scaling relationships. For the first time, normalization equations have been presented with demonstrated effectiveness in adjusting strength measures for body size in a group of children, adolescents, and young adults with CP.

Surgical treatment of spasticity in children: comparison of selective dorsal rhizotomy and intrathecal baclofen pump implantation

INTRODUCTION

Neurosurgical treatments for spasticity in children include the traditional selective dorsal rhizotomy (SDR) and intrathecal baclofen pumps (ITBPs), which have been widely used in the past decade as an attractive alternative. The purpose of the study was to examine and compare the outcomes of these two procedures in the treatment of children with severe spasticity.

MATERIALS AND METHODS

A consecutive series of 71 children who underwent SDR for treatment of spasticity was compared with a group of 71 children matched by age and preoperative score on the Gross Motor Function Classification System (GMFCS) who underwent ITBP placement. Change in GMFCS score, lower-extremity tone (based on the Modified Ashworth-Bohannon Scale), and lower-extremity passive range of movement (PROM) at 1 year as well as the need for subsequent orthopedic procedures and parents' satisfaction were selected as outcome measures.

RESULTS

At 1 year, both SDR and ITBP decreased tone, increased PROM, and improved function. Both procedures resulted in a high degree of patient satisfaction. Compared with ITBP, SDR provided a larger magnitude of improvement in tone (-2.52 vs -1.23, p < 0.0001), PROM (-0.77 vs -0.39, p = 0.0138), and gross motor function (-0.66 vs -0.08, p < 0.0001). In addition, fewer patients in the SDR group required subsequent orthopedic procedures (19.1 vs 40.8%, p = 0.0106).

CONCLUSIONS

For children with moderate to severe spasticity, SDR and ITBP are both effective surgical treatments. Our results indicate SDR is more effective in reducing the degree of spasticity and improving function than ITBP is in this group of patients.

Relationships Between Spasticity, Strength, Gait, and the GMFM-66 in Persons With Spastic Diplegia Cerebral Palsy

OBJECTIVE

To determine the relationships between spasticity, strength, and the functional measures of gait and gross motor function in persons with spastic diplegia cerebral palsy (CP).

DESIGN

Retrospective, cross-sectional study.

SETTING

Hospital clinic.

PARTICIPANTS

Ninety-seven participants (49 boys, 48 girls; mean age+/-standard deviation, 9.11+/-4.8 y) with spastic diplegia CP were tested once.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

A KinCom dynamometer was used to objectively measure spasticity (ankle plantarflexors, knee flexors, hip adductors) and maximum strength (ankle dorsiflexors and plantarflexors, knee flexors and extensors, hip abductors and adductors). A gait analysis was conducted to evaluate linear variables (gait speed, stride length, cadence) and kinematic variables (ankle dorsiflexion, foot progression, knee and hip flexion, pelvic tilt at initial contact and ankle dorsiflexion, knee and hip flexion, pelvic tilt, trunk rotation range of motion) during gait. Gross motor function was measured using the Gross Motor Function Measure (GMFM-66) and separately, the GMFM walking, running & jumping dimension. Multiple linear regression analysis was used to determine the relationships between spasticity, strength, gait, and the GMFM (P<.05).

RESULTS

Spasticity did not account for a substantial amount of explained variance in gait and gross motor function (up to 8% for the GMFM walking, running & jumping dimension). Moderate to high correlations existed between strength and gait linear data and function, accounting for up to 69% of the explained variance (strength and GMFM-66, r2=.69).

CONCLUSIONS

For this cohort of participants with spastic diplegia CP who ambulated with or without an assistive device, strength was highly related to function and explained far more of the variance than spasticity. The results may not be generalized to those with more severe forms of CP.

Selective dorsal rhizotomies in the treatment of spasticity related to cerebral palsy

RATIONALE

Selective dorsal rhizotomy (SDR) is a surgical technique developed over the past decades to manage patients diagnosed with cerebral palsy suffering from spastic diplegia. It involves selectively lesioning sensory rootlets in an effort to maintain a balance between elimination of spasticity and preservation of function. Several recent long-term outcome studies have been published. In addition, shorter follow-up randomized controlled studies have compared the outcome of patients having undergone physiotherapy alone with those that received physiotherapy after selective dorsal rhizotomy.

MATERIALS AND METHODS

In this account, we will discuss the rationale and outcome after SDR. The outcome is addressed in terms of the gross motor function measurement scale (GMFM), degree of elimination of spasticity, strength enhancement, range of motion, fine motor skills, activity of daily living, spastic hip, necessity for postoperative orthopedic procedures, bladder and sphincteric function, and finally possible early or late complications associated with the procedure.

CONCLUSION

We conclude that SDR is a safe procedure, which offers durable and significant functional gains to properly selected children with spasticity related to cerebral palsy.

Selective dorsal rhizotomy for spastic cerebral palsy: a review

OBJECTIVE

The purpose of this report is to review the historical development, current operative techniques, selection criteria, outcomes, and complications of selective dorsal rhizotomy (SDR) for treatment of spastic cerebral palsy (CP).

MATERIALS AND METHODS

This review is based on a review of literature and personal observations.

RESULTS

SDR has evolved from the 1960s onwards into a standard neurosurgical procedure for spastic CP. There is much variation in the operative technique among surgeons with respect to the level of exposure, electrophysiological guidance, and extent of rhizotomies. Appropriate selection of patients for SDR requires determination that spasticity, not dystonia, is the major disabling hypertonia and that the lower limbs are maximally involved. Positive outcomes have been well demonstrated in the impairment, functional limitations, and disability dimensions, as per the National Center for Medical Rehabilitation Research Model of Dimensions of the Disabling Process. Complications have been relatively few.

CONCLUSIONS

SDR is the procedure of choice for treatment of spasticity in spastic diplegic CP and in selected children with spastic quadriplegic CP. Optimal selection and outcomes are achieved using a multidisciplinary approach.

Predicting functional change from preintervention measures in selective dorsal rhizotomy

OBJECT

In this investigation the authors attempted to predict change in function following selective dorsal rhizotomy (SDR) and intensive physical therapy in patients with spastic diplegic cerebral palsy (CP) based on multidomain preintervention measures.

METHODS

Data pertaining to 22 children with CP were collected before the SDR and again 20 months afterward. Although equations for predicting change in gait speed and function (such as the Gross Motor Function Measure) were derived, the 95% confidence interval (CI) widths were too broad to make accurate predictions that were clinically useful outside the study group.

CONCLUSIONS

Future work should be focused on developing additional measures such as lower-extremity motor control and balance in an attempt to reduce the CIs to more clinically relevant values.

Percutaneous radiofrequency lesion adjacent to the dorsal root ganglion in the treatment of spasticity and pain in children with cerebral palsy

The use of percutaneous radiofrequency (RF) lesion adjacent to the dorsal root ganglion (RF-DRG) in the treatment of pain has been established for years. A relatively novel indication for RF-DRG treatment is spasticity in children with cerebral palsy. In this article the pathophysiology and management of spasticity is discussed with an emphasis on the role of RF-DRG. In the management of spasticity, RF-DRG could prove to be a little invasive treatment option with little adverse effects.

Effect of selective dorsal rhizotomy in the treatment of children with cerebral palsy

OBJECT

In this investigation the authors compared impairment and functional outcomes between two groups of children with cerebral palsy (CP): one group underwent selective dorsal rhizotomy (SDR) followed by intensive physical therapy (PT), and the other group underwent the latter only (PT group). Data from an age-matched group of children without disability (nondisabled [ND] group) were also collected.

METHODS

Data pertaining to the 68 children with CP were collected before any intervention and again 8 and 20 months afterwards. Data regarding the 40 children in the ND group were collected in a single session.

CONCLUSIONS

Although patients in both groups with CP were weaker than those in the ND group, they did have strength gains. Gait speed in the SDR-PT group was slower than that in the ND group preoperatively but not at 20 months postoperatively. Gait speed in the PT group remained slower than that in the ND group. The pre- to postoperative change in the Gross Motor Abilities Estimate score was significantly greater in the SDR-PT group than in the PT-only group. An effective treatment for children with CP, SDR offers gains in strength, gait speed, and overall gross motor function.

Test-retest reliability of isokinetic dynamometry for the assessment of spasticity of the knee flexors and knee extensors in children with cerebral palsy

OBJECTIVE

To assess test-retest reliability of the peak resistance torque and slope of work methods of spasticity measurement of the knee flexors and extensors in children with cerebral palsy (CP).

DESIGN

Test-retest reliability study.

SETTING

Pediatric orthopedic hospital.

PARTICIPANTS

Fifteen children with CP.

INTERVENTION

Knee extensor and flexor spasticity was assessed with an isokinetic dynamometer using passive movements at 15 degrees, 90 degrees, and 180 degrees/s taken 1 hour apart.

MAIN OUTCOME MEASURES

Peak resistive torque and work were calculated. The relative and absolute test-retest reliability was calculated by using intraclass correlation coefficients (ICCs) and Bland-Altman plots, respectively.

RESULTS

Relative reliability was good (ICC>.75) for slope-of-work and peak resistance torque measurements at a velocity of 180 degrees/s, whereas reliability of peak torque measurements was decreased (ICC<.51) at slower velocities for both muscle groups. The 95% limits of agreement of Bland-Altman plots contained most data points for both methods, but the width of the limits of agreement were wide.

CONCLUSIONS

The measurement of spasticity of the knee extensors and flexors in children with CP using peak-resistance torque at 180 degrees/s and the slope of work method has acceptable relative test-retest reliability. However, the absolute reliability of spasticity data should be considered cautiously.

Voluntary muscle activation, contractile properties, and fatigability in children with and without cerebral palsy

Cerebral palsy (CP) may lead to profound weakness in affected portions of the extremities and trunk. Knowing the mechanisms underlying muscle weakness will help to better design interventions for increasing force production in children with CP. This study quantified voluntary muscle activation, contractile properties, and fatigability of the quadriceps femoris and triceps surae in children with and without CP. Twelve children with CP (7-13 years) and 10 unaffected children (controls, 8-12 years) were assessed for (1) voluntary muscle activation during maximum voluntary isometric contractions (MVICs); (2) antagonist coactivation during agonist MVICs; (3) contractile properties, and (4) fatigability using electrically elicited tests. Children with CP were significantly weaker, had lower agonist voluntary muscle activation, and greater antagonist coactivation. In children with CP, the quadriceps normalized force-frequency relationship (FFR) was shifted upward at low frequencies and was less fatigable than controls. No differences were seen between groups in the normalized FFR and fatigability of the triceps surae. In addition, no differences were seen in the sum of the time to peak tension and half-relaxation times between groups for either muscle. Because children with CP demonstrated large deficits in voluntary muscle activation, using voluntary contractions for strength training may not produce forces sufficient to induce muscle hypertrophy. Techniques such as enhanced feedback and neuromuscular electrical stimulation may be helpful for strengthening muscles that cannot be sufficiently recruited with voluntary effort.

Validation of portable muscle tone measurement device for quantifying velocity-dependent properties in elbow spasticity

The objective of this study is to develop a portable device for quantifying the velocity-dependent properties of spastic elbow muscles. Based on a motor-driven system, validation tests of the portable system such as accuracy and response of sensors were first examined. Furthermore, simulated modules (inertia, damper and spring) as well as elbow joints (15 control and 15 hemiplegic subjects) were manually stretched under four different frequencies (1/3, 1/2, 1 and 3/2 Hz) through 60 degrees range of motion. Joint resistance and displacement during sinusoidal stretch were collected for further analysis. Two quantitative parameters (i.e., viscous components under each frequency and averaged viscosity across four frequencies) were derived to estimate the velocity-dependent properties of elbow joint. Tests of simulated modules confirm the manual stretch protocol and data analysis are valid in estimating the velocity-dependent component during a sinusoidal stretch. Compared to normal control, viscous component in each stretch frequency and averaged viscosity were significantly higher in subjects with spasticity (P < 0.001). The viscous component and averaged viscosity were found highly correlated with the modified Ashworth scale. These findings suggest that measurements of viscous component and averaged viscosity during manual sinusoidal stretching using the portable device could be clinically useful in evaluating spasticity.

Treatment of spastic diplegia in patients with cerebral palsy: Part II

This review article describes the evaluation, treatment options, and expected outcomes for many of the common deformities of the lower extremities in patients with cerebral palsy. The evaluation tools including gait analysis will be applied to each specific deformity. Dynamic components are addressed with spasticity management and appropriate muscle and tendon procedures. The static components are treated with bony procedures, including various osteotomies and arthrodesis, incorporating biomechanical principles.

Quantifying Active Ankle Range of Motion in Cerebral Palsy Following Selective Dorsal Rhizotomy

This study was conducted to determine whether an objective and quantitative measure for active ankle range of motion would be sensitive to differences between persons of able body and those with cerebral palsy (CP), and between pre- and postselective dorsal rhizotomy (SDR). Twelve children with spastic diplegia CP were tested before undergoing an SDR, and again after 8 months of intensive physical therapy (SDR group). Fourteen other children with spastic diplegia were tested initially and again 8 months following no intervention but maintaining their existing level of physical therapy (CP group). Twenty age-matched children of able body were tested once (AB group). A video system recorded active sagittal plane ankle movements as the seated child independently performed maximum dorsiflexion and plantarflexion. The data were tracked and analyzed to determine end-range dorsiflexion and plantarflexion, and total active ankle range of motion. Repeated-measures ANOVA and Tukey post hoc tests were used to test for significant differences among and between groups, p < 0. 05. Results for the SDR group indicated a significant increase in end-range dorsiflexion and total range of motion following the surgery, with no changes in any measures for the CP group. Results for both groups with CP indicated differences vs. the AB group. The measure provided additional information from what has previously been reported for active ankle range of motion. The integration of this measure with other objective measures for quantifying impairments and presurgical function may be useful in predicting post-SDR gait status and other functional activities.

Long-term functional outcome after selective posterior rhizotomy

OBJECT

Selective posterior rhizotomy (SPR) is a well-recognized treatment for children with spastic cerebral palsy (CP). Few investigators have used quantitative outcome measures to assess the surgical results beyond 3 years. The authors analyzed data obtained from the McGill Rhizotomy Database to determine the long-term functional outcome of children who had undergone selective dorsal rhizotomy accompanied by intraoperative electrophysiological monitoring.

METHODS

The study population was composed of children with spastic CP who underwent SPR and were evaluated by a multidisciplinary team preoperatively, and at 6 months and 1 year postoperatively. Quantitative standardized assessments of lower-limb spasticity, passive range of motion, muscle strength, and ambulatory function were obtained. Of the 93 patients who met the entry criteria for the study, 71 completed the 3-year and 50 completed the 5-year assessments, respectively. Statistical analysis demonstrated significant improvements in spasticity, range of motion, and functional muscle strength at 1 year after SPR. The preoperative, 1-, 3-, and 5-year values for the global score of the Gross Motor Function Measure were 64.6, 70.8, 80, and 85.6, respectively. The greatest improvement occurred in the dimensions reflecting lower-extremity motor function, where the mean change was 10.1% at 1 year, 19.9% at 3 years, and 34.4% at the 5-year follow-up review in comparison with the baseline value. This was associated with a lasting improvement in alignment and postural stability during developmental positions, as well as increased ability to perform difficult transitional movements.

CONCLUSIONS

The results of this study support the presence of significant improvements in lower-limb functional motor outcome 1 year after SPR, and the improvements persist at 3 and 5 years. The authors conclude that SPR in conjunction with intraoperative stimulation is valuable for permanently alleviating lower-limb spasticity while augmenting motor function.

Objective measurement of muscle strength in children with spastic diplegia after selective dorsal rhizotomy

OBJECTIVES

To examine changes in isometric muscle strength at the elbow, knee, and ankle at 6 months and 1 year after selective dorsal rhizotomy (SDR) and to determine if SDR altered the frequency of muscle cocontraction.

DESIGN

Prospective outcome study of a consecutive sample.

SETTING

Children's hospital.

PATIENTS

Ten children with spastic diplegia (7 independent and 3 dependent ambulators who used assistive devices) and 8 age-matched controls.

INTERVENTIONS

SDR; physical and occupational therapy; elbow, knee, and ankle measured for flexion and extension strength during three 10-second isometric contractions for each muscle group; and monitored cocontraction measured via muscle electrodes.

MAIN OUTCOME MEASURES

Absolute and normalized values of isometric strength; and alterations in the frequency of cocontraction at 6 months and 1 year postoperatively.

RESULTS

Children with spastic diplegia showed significantly weaker knee extensors, ankle dorsiflexors, and ankle plantarflexors than age-matched controls. There were no significant differences in strength between the 2 groups in the elbow flexors, elbow extensors, and knee flexors. Isometric strength did not increase or decrease significantly after SDR. Cocontraction during knee extension was normalized after SDR, whereas cocontraction during ankle plantarflexion was unchanged by SDR in the majority of children.

CONCLUSION

SDR did not result in a significant decrease in muscle strength in ambulatory children with spastic diplegia. The normalization of the electromyographic patterns at the knee and not the ankle after SDR lends support to the premise that in children with cerebral palsy cocontraction is multifaceted, representing a volitional strategy to enhance control, as well as a disorder of the mechanisms that govern patterns of muscle activity.

Functional outcome after isolated acetabular fractures

OBJECTIVE

To evaluate objectively the effectiveness of current surgical management of displaced acetabular fractures. To provide insight into how these evaluation methods can be used to identify areas in which improvements in surgery and rehabilitation can be pursued to improve patient outcomes.

DESIGN

Consecutive case series.

SETTING

University medical center.

PATIENTS

Fifteen patients were studied, each with an isolated, displaced acetabular fracture treated with a Kocher-Langenbeck approach.

MAIN OUTCOME MEASURES

Primary outcome measures included hip muscle strength, including work (Joules/minute) and maximum torque (30 degrees/second) for abductors/adductors and flexors/extensors. Gait analysis of patients and able-bodied cohorts, including stride length, speed, and cadence, were also assessed. Motion analysis during gait was also studied for each body segment, including the trunk, pelvis, hip, knee, and ankle, in the sagittal, frontal, and axial planes. Motion data for the affected side was compared with motion data for the unaffected side, and linear gait findings for the study patients were compared to able-bodied cohorts. An assessment of clinical outcome was performed by completion of a validated Musculoskeletal Function Assessment (MFA) questionnaire and the were results correlated with muscle strength and gait analysis. Secondary outcome measures included adequacy of fracture reduction, radiographic grade, the presence and severity of heterotopic ossification at the time of the most recent follow-up, and passive range of motion of the affected and unaffected hips.

RESULTS

No statistical differences in muscle strength for each of the major muscle groups were found when the affected limb was compared with the unaffected limb. No statistical differences were found between the study patients and the able-bodied cohorts with regards to stride length, gait speed, and cadence. The only significant difference found in body segment position was trunk inclination. When the study patients were compared with able-bodied cohorts, the patients tended to walk with greater forward inclination of their trunks; this was true for all phases of gait. Total MFA scores averaged 22 (range, 0-57). Patients could be separated into two separate groups based on their total MFA score. One group (n = 6) had an average MFA score of 7 (range, 0-10), while a second group (n = 9) had an average MFA score of 32 (range, 12-57). The scores of study patients as a whole, and those of each individual group of patients, were compared with known MFA scores for nonpatients and patients in the Orthopaedic Trauma Association/Association for the Study of Internal Fixation (OTA/AO) injury group (hip and thigh). When the muscle strengths of these two groups of patients were compared, all hip flexion and extension variables were significantly weaker in the group with an average MFA score of 32, whereas none of the gait variables were different between the two groups. At an average follow-up of 24 months, seven patients had an excellent radiographic grade, four patients had a good grade, two patients had a fair grade, and two patients had a poor grade. These radiographic grades were in contrast to achieving an anatomic reduction in eleven patients, a satisfactory reduction in three patients, and an unsatisfactory reduction in one patient. Heterotopic ossification was found in eight patients, four patients had Grade 1, and four patients, had Grade 2. No statistically significant differences were observed when each MFA group was compared with each of these radiographic variables. Passive hip range of motion was not statistically different when the affected hip was compared with the unaffected hip.

CONCLUSIONS

Standardized muscle strength determination, gait, and motion analysis, and completion of an MFA questionnaire provided a thorough and revealing evaluation of patients who have undergone open reduction and internal fixation (ORIF) of a displaced acetabular fracture. Minimal alterations in body posture and affected limb motion were present in patients displaying relatively normal gait parameters, including stride length, speed, and cadence. Despite dissection of the hip musculature during surgery, normal muscle strength recovery was possible after operative repair of these acetabular fractures. However, functional outcome, as determined by MFA scores, was considerably poorer in those patients with significantly weaker hip flexion and extension strength, compared with those of patients with more desirable MFA scores. Based on the current data, it appears that the use of these and similar evaluation instruments can allow determination of factors that negatively affect outcome (hip flexion and extension strength), which otherwise may remain unknown. It is possible that identification and treatment of these factors will improve the quality of life for patients after this type of injury.

Outcome measurement of effectiveness of botulinum toxin type A in children with cerebral palsy: an ICIDH-2 approach

The ICIDH-2 serves as a useful framework for differentiating measurement by dimensions of the disabling process. Such differentiation is important to achieve more valid measurement of health related outcomes. We have attempted to examine one intervention, treatment with botulinum toxin type A, for one patient population, children with cerebral palsy, and to describe the outcome measures used in the evaluation of that intervention using this evolving classification system. This process supports the concept that measurement of health outcomes should focus on the nature and extent of functional limitations in physical, social and psychological domains. The selection of measurement outcomes must be determined not only by the requirements of the scientific process but also by the needs of the patients who are the intended beneficiaries of the intervention.

A Measure of Motor Control at the Knee in Cerebral Palsy

This investigation developed a measure of motor control for the knee extensors in adults with cerebral palsy (CP). Four adults with CP and 4 able-bodied (AB) adults participated. A KinCom dynamometer rotated the knee from approximately 90º of knee flexion to 10º/s less than the participant’s maximum knee extension at a speed of 10º/s, while the participant attempted to match a 44.5-N “target” force. The average, standard deviation, and median frequency of the force-time data were used to describe the test results. The individual force values for the AB group were near the target force and clustered together. The values for the CP group were also near the target force, but displayed greater variation. The average standard deviation for the CP group was more than three times larger than that of the AB group. The average median frequency for the CP group was less than that of the AB group. Results pointed to differing strategies for each group as they attempted to match the target force. The AB group attempted to match the target force with frequent small-magnitude force changes, while the CP group attempted to match the target force with fewer oscillations of greater magnitude. The methods employed in the present investigation are initial attempts to quantify one aspect of motor control, a visually guided tracking task.

Spasticity versus strength in cerebral palsy: relationships among involuntary resistance, voluntary torque, and motor function

Despite the lack of consensus of the role of spasticity in the observed motor disability in cerebral palsy (CP), alleviation of spasticity remains a primary focus in the clinical management of these patients. The purposes of this study were to: (1) quantify voluntary torque and passive resistance across speeds in the hamstrings and quadriceps muscle groups with respect to the presence of stretch responses and/or passive muscle stiffness in patients with CP compared to age-related children without disability, and (2) relate these parameters to each other and to functional performance, as measured by the Gross Motor Function Measure (GMFM), in CP. Included were 23 subjects with CP, sub-grouped by the presence or absence of stretch responses as determined by electromyography, and 9 subjects without CP. Results indicated that peak torque was considerably greater in the comparison group than for each of the CP groups and resistance was greater in the CP group with spasticity compared to the nonspastic CP group in both muscles at all speeds. Stiffness differed between the spastic CP group and the comparison group only for the quadriceps at the fastest speed. Higher passive resistance torque and stiffness were correlated with decreased voluntary torque, particularly for the antagonists, and with lower GMFM scores. In conclusion, strength and motor function are related to the magnitude of resistance torque and stiffness in CP, although the small amount of variance explained reinforces the multidimensional nature of this disorder, and the challenges inherent in managing it.

Advances in prevention and treatment of cerebral palsy

In recent years there have been a number of advances in understanding of predisposing and protective factors in the development of cerebral palsy in infants. Multiple gestation births, maternal infection, and maternal and fetal thrombophilic conditions all predispose to the development of CP in the infant. Opportunities for prevention of CP may develop from an improved understanding of these factors and their mechanisms of operation. Similar progress has been made in the evaluation of treatments for CP and the effects of these treatments on the individual's impairment, function, and disability. Selective posterior rhizotomy and Botulinum toxin A are now widely used in the treatment of spasticity. The challenge remains to determine how effectively these promising interventions can alter long-term function and quality of life outcomes in children and adults with CP.

Quantifying muscle activity in non-ambulatory children with spastic cerebral palsy before and after selective dorsal rhizotomy

Cerebral palsy is a condition that results in varying degrees of functional deficits. The goal of this study was to develop an objective measure of muscle activity during a prescribed voluntary motor task in non-ambulatory children with spastic cerebral palsy. While performing a simultaneous hip/knee flexion task from the supine position, followed by return to the starting position, electromyographic and kinematic data were obtained from the right leg of eight children before and after selective dorsal rhizotomy and compared with eight age-matched controls. The electromyographic and kinematic data were combined to determine for each muscle of interest (tibialis anterior, soleus, vastus lateralis, biceps femoris) the percentage of the movement cycle for which the muscle was acting concentrically, eccentrically, isometrically or was considered inactive. Averaged over the four muscles, isometric activity decreased by 38% post-op and the time the muscles were inactive increased by 37% following surgery. The percentages of concentric and eccentric activity did not differ significantly between pre- and post-op conditions. Post-operatively, the percentage muscle activity patterns of the children with cerebral palsy more closely resembled that of the control children: averaged across all muscles and contraction types, the difference between the control children and the children with cerebral palsy was reduced by 50% following surgery. This measurement technique indicates promise as a method for quantifying muscle activity during voluntary motor tasks in non-ambulatory children with cerebral palsy.

Hip Spasticity and Strength in Children with Spastic Diplegia Cerebral Palsy

Hip spasticity and strength from 44 children with cerebral palsy (CP) and 44 children with able bodies (AB) were compared. For spasticity, a KinCom dynamometer abducted the passive hip at 4 different speeds and recorded the resistive adductor torques. Work values for the torque-angle data were calculated at each speed. Linear regression derived the slope for the line of best fit for the work-velocity data to determine the spasticity measure. For strength, the KinCom rotated the hip from maximum adduction to maximum abduction at a speed of 10°/s while the child performed a maximum abduction concentric contraction. Tests were reversed to record maximum adduction. Maximum torques and work by the abductors and adductors were calculated. Spasticity in the adductors for the CP group was significantly greater than values recorded for the AB group. All strength measures were significantly less than the AB group. Results provide objective information, quantifying hip spasticity and strength in children with CP.

Nerve rootlets to be sectioned for spasticity resolution in selective dorsal rhizotomy

BACKGROUND

The goal of this study is to confirm the efficacy of the protocol for selective dorsal rhizotomy (SDR). In this protocol, rootlets to be sectioned are selected by palpable responses elicited by intraoperative electrical stimulation, without detailed electromyographic classifications.

METHODS

Thirty-six children with spasticity due to cerebral palsy underwent SDR according to our protocol. Priority was given to sectioning rootlets that showed palpable clonic or bilateral responses, which were considered abnormal, over sectioning rootlets that merely had hyperactive responses to intraoperative stimulation. The results of intraoperative monitoring and sectioning amount were analyzed by physical evaluation.

RESULTS

Significant improvements were obtained in passive range of motion and muscle tone of the lower extremities. The total percentages of rootlets with abnormal and hyperactive responses at L3 and S1 were bilaterally correlated with preoperative spasticity of the hip adductors and the plantar flexors, respectively. When rootlets with hyperactive responses were excluded from the correlation analysis, no bilateral correlation was observed. From the correlation analyses between the improvement in the physical evaluation and the amount of nerve sectioned, it was concluded that a greater improvement in muscle tone in all examined muscles, except the hamstrings, could be obtained if larger amounts of nerve roots were sectioned.

CONCLUSION

The number of rootlets with palpable abnormal and hyperactive responses elicited by intraoperative stimulation reflects the preoperative spasticity of multiple muscles. This implies that only selecting rootlets with palpable responses can be reliable. Because more sectioning leads to better spasticity resolution, our protocol should be reviewed to increase the percentage of rootlets sectioned with hyperactive responses, especially for innervated levels of severely affected muscles.

The surgical treatment of spasticity

Many neurosurgical procedures have been designed for or applied to the treatment of spasticity arising from different disorders, including cerebral palsy; traumatic, ischemic, or hypoxic brain injury, multiple sclerosis, and spinal cord injury. Neurosurgical procedures are primarily aimed at reducing spasticity by interrupting the stretch reflex at various sites along the spinal reflex arc or attempting to increase the centrally mediated inhibitory influence on the pool of motor neurons in the anterior horn. Surgical interventions for spasticity can be classified into peripheral ablative procedures, such as rhizotomy or peripheral neurectomy, and central ablative procedures, such as cordectomy, myelotomy, or stereotactic procedures. Non-ablative procedures include peripheral nerve or motor point blocks, the implantation of cerebellar or spinal stimulators, and the implantation of subdural catheters for infusion of pharmacologic agents to increase inhibitory activity. Several proposed mechanisms for spasticity are reviewed so that the rationale for the various surgical interventions for spasticity described may be better understood.

Changes in ankle spasticity and strength following selective dorsal rhizotomy and physical therapy for spastic cerebral palsy

OBJECT

In this investigation the authors quantified changes in ankle plantarflexor spasticity and strength following selective dorsal rhizotomy (SDR) and intensive physical therapy in patients with cerebral palsy (CP).

METHODS

Twenty-five patients with cerebral palsy (CP group) and 12 able-bodied volunteers (AB controls) were tested with a dynamometer. For the spasticity measure, the dynamometer was used to measure the resistive torque of the plantarflexors during passive ankle dorsiflexion at five different speeds. Data were processed to yield a single value that simultaneously encompassed the three key elements associated with spasticity: velocity, resistance, and stretch. For the strength test, the dynamometer rotated the ankle from full dorsiflexion to full plantarflexion while a maximum concentric contraction of the plantarflexors was performed. Torque angle data were processed to include the work done by the patient or volunteer on the machine. Plantarflexor spasticity values for the CP group were significantly greater than similar values for the AB control group prior to surgery but not significantly different after surgery. Plantarflexor strength values of the CP group were significantly less than those of the AB control group pre- and postsurgery. Postsurgery strength values did not change relative to presurgery values.

CONCLUSIONS

The spasticity results of the present investigation agreed with those of previous studies indicating a reduction in spasticity for the CP group. The strength results did not agree with the findings of most previous related literature, which indicated that a decrease in strength should have occurred. The strength results agreed with a previous investigation in which knee flexor strength was objectively examined, indicating that strength did not decrease as a consequence of an SDR. The methods of this investigation could be used to improve SDR patient selection.