Spasticity: pathophysiology and management

Riluzole for treating spasticity in patients with chronic traumatic spinal cord injury: Study protocol in the phase ib/iib adaptive multicenter randomized controlled RILUSCI trial

BACKGROUND

Satisfactory treatment is often lacking for spasticity, a highly prevalent motor disorder in patients with spinal cord injury (SCI). Low concentrations of riluzole potently reduce the persistent sodium current, the post-SCI increase in which contributes to spasticity. The repurposing of this drug may therefore constitute a useful potential therapeutic option for relieving SCI patients suffering from chronic traumatic spasticity.

OBJECTIVE

RILUSCI is a phase 1b-2b trial designed to assess whether riluzole is a safe and biologically effective means of managing spasticity in adult patients with traumatic chronic SCI.

METHODS

In this multicenter double-blind trial, adults (aged 18-65 years) suffering from spasticity after SCI (target enrollment: 90 participants) will be randomly assigned to be given either a placebo or a recommended daily oral dose of riluzole for two weeks. The latter dose will be previously determined in phase 1b of the study by performing double-blind dose-finding tests using a Bayesian continuous reassessment method. The primary endpoint of the trial will be an improvement in the Modified Ashworth Score (MAS) or the Numerical Rating Score (NRS) quantifying spasticity. The secondary outcomes will be based on the safety and pharmacokinetics of riluzole as well as its impact on muscle spasms, pain, bladder dysfunction and quality of life. Analyses will be performed before, during and after the treatment and the placebo-controlled period.

CONCLUSION

To the best of our knowledge, this clinical trial will be the first to document the safety and efficacy of riluzole as a means of reducing spasticity in patients with chronic SCI.

TRIAL REGISTRATION

The clinical trial, which is already in progress, was registered on the ClinicalTrials.gov website on August 9, 2016 under the registration number NCT02859792.

TRIAL SPONSOR

Assistance Publique-Hôpitaux de Marseille.

Optimizing the Management of Disabling Spasticity Following Spinal Cord Damage: The Ability Network-An International Initiative

Optimizing the treatment of disabling spasticity in persons with spinal cord damage is hampered by a lack of consensus regarding the use of acceptable definitions of spasticity and disabling spasticity, and the relative absence of decision tools such as clinical guidelines and concise algorithms to support decision-making within the broader clinical community. Many people with spinal cord damage are managed outside specialist centers, and variations in practice result in unequal access to best practice despite equal need. In order to address these issues, the Ability Network-an international panel of clinical experts-was initiated to develop management algorithms to guide and standardize the assessment, treatment, and evaluation of outcomes of persons with spinal cord damage and disabling spasticity. To achieve this, consensus was sought on common definitions through facilitated, in-person meetings. To guide patient selection, an in-depth review of the available tools was performed and expert consensus sought to develop an appropriate instrument. Literature reviews are guiding the selection and development of tools to evaluate treatment outcomes (body functions, activity, participation, quality of life) as perceived by people with spinal cord damage and disabling spasticity, and their caregivers and clinicians. Using this approach, the Ability Network aims to facilitate treatment decisions that take into account the following: the impact of disabling spasticity on health status, patient preferences, treatment goals, tolerance for adverse events, and in cases of totally dependent persons, caregiver burden.

Pediatric tone management

Tone management is one of the primary roles of a pediatric physiatrist. Hypertonicity frequently inhibits normal movement patterns in children with central nervous system lesions but at times can reinforce muscle group firing and be useful for a child's function. Treatment approaches should be individualized based on functional goals, degree of impairment, interference with care, and type and location of hypertonicity. Treatment plans should be created in collaboration with all individuals caring for the child. There are many causes of hypertonicity as well as many nonsurgical and surgical treatments. Historical and current evidence-based treatments are reviewed.

Adherence associated with oral medications in the treatment of spasticity

OBJECTIVE

To examine adherence to baclofen, tizanidine, and dantrolene (U.S. Food and Drug Administration-approved oral spasticity medications), and identified determinants of adherence.

DESIGN

A retrospective administrative claims data analysis that used medical and pharmacy claims data and enrollment information from a large, national U.S. health plan.

SUBJECTS AND METHODS

The subjects were commercial health plan members who initiated treatment on baclofen, tizanidine, or dantrolene from January 1, 2004, through September 30, 2009, and who had stroke, spinal cord injury, traumatic brain injury, cerebral palsy, or multiple sclerosis. Descriptive and logistic regression statistical analyses were performed.

MAIN OUTCOME MEASUREMENTS

Outcomes were adherence, measured as continuous medication possession ratio (MPR) and as a binary indicator (MPR ≥0.80, adherent; MPR <0.80, nonadherent), change in oral spasticity medication, and use of nonoral spasticity therapy.

RESULTS

The study population included 2840 subjects. Adherence overall was poor: the range of mean unadjusted MPR values was 0.10-0.50, which indicated that, at best, the subjects were adherent to their index spasticity medications for 50% of their treatment periods. Unadjusted overall MPRs for baclofen and tizanidine were 20.4% and 9.1%, respectively. Fewer than 5% of subjects changed oral spasticity medications. The results of logistic regression to identify determinants of adherence showed that subjects treated with tizanidine versus baclofen had 37.4% lower odds of adherence and that subjects with traumatic brain injury versus stroke had 77.5% lower odds of adherence. The odds of adherence increased with age and with preindex contracture or decubitus ulcer.

CONCLUSIONS

Adherence to oral spasticity medication was poor irrespective of index spasticity medication or condition. Results from this study indicated that physicians cannot assume that patients are adherent to prescribed oral spasticity medications. A more complete understanding of the reasons behind nonadherence is required.

Impact of spinal cord injury on sexuality: broad-based clinical practice intervention and practical application

This study focuses on the impact a spinal cord injury may have on achieving physical and emotional intimacy, and potential to maximize sexual ability and quality of life. Spinal cord injury is a traumatic, life-altering event that is usually associated with loss of motor and sensory function, as well as sexual impairment. At the time of injury, the individual is faced with devastating loss and an abundance of new information in a setting of extreme stress and challenge. In the acute rehabilitation setting, there is often a considerable void in providing education and resources regarding sexual concerns and needs. There is a positive relationship between sexual education and sexual activity. The impact of inadequate sexual counseling and education as a part of rehabilitation can be deleterious.

Muscle spasticity associated with reduced whole-leg perfusion in persons with spinal cord injury

OBJECTIVE

To determine the association between peripheral blood flow and spasticity in individuals with spinal cord injury (SCI).

DESIGN

A cross-sectional study with measurements of muscle spasticity and whole-limb blood flow in individuals with SCI.

SETTING

University of Texas at Austin and Brain & Spine Recovery Center, Austin, TX, USA.

PARTICIPANTS

Eighteen individuals (14 males and 4 females) with SCI were classified into high (N = 7), low (N = 6), and no (N = 5) spasticity groups according to the spasticity levels determined by the modified Ashworth scale scores.

INTERVENTIONS

Whole-limb blood flow was measured in the femoral and brachial arteries using Doppler ultrasound and was normalized to lean limb mass obtained with dual-energy X-ray absorptiometry.

OUTCOME MEASURES

Limb blood flow and muscle spasticity.

RESULTS

Age, time post-SCI, and the American Spinal Injury Association impairment scale motor and sensory scores were not different among groups with different muscle spasticity. Femoral artery blood flow normalized to lean leg mass was different (P = 0.001) across the three spasticity groups (high 78.9 ± 16.7, low 98.3 ± 39.8, no 142.5 ± 24.3 ml/minute/kg). Total leg muscle spasticity scores were significantly and negatively correlated with femoral artery blood flow (r = -0.59, P < 0.01). There was no significant difference in brachial artery blood flow among the groups.

CONCLUSIONS

Whole-leg blood flow was lower in individuals with greater spasticity scores. These results suggest that a reduction in lower-limb perfusion may play a role, at least in part, in the pathogenesis leading to muscle spasticity after SCI.

The spinal cord injury spasticity evaluation tool: development and evaluation

OBJECTIVE

To develop and assess the reliability and validity of a new scale designed to measure the impact of spasticity on daily life in people with spinal cord injury (SCI).

DESIGN

Scale development and assessment.

SETTING

General community.

PARTICIPANTS

Community-dwelling persons with chronic SCI and spasticity participated in study 1 (n=9), study 2 (n=19), and study 3 (n=61).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Study 1: participant definitions of spasticity and list of scale items. Study 2: scale refinement, face validity, and time to complete. Study 3: internal consistency, test-retest reliability, and construct validity.

RESULTS

The Spinal Cord Injury Spasticity Evaluation Tool (SCI-SET) is a 7-day recall self-report questionnaire that takes into account both the problematic and useful effects of spasticity on daily life in people with SCI. The scale exhibited good face validity and required 6.8+/-2.6 minutes to complete. The internal consistency (alpha) and intraclass correlation coefficient of the SCI-SET were .90 and .91, respectively. Construct validity was supported by correlations (r range, -.48 to .68; P<.01) between SCI-SET scores and theoretically meaningful constructs.

CONCLUSIONS

The SCI-SET fills a need for a reliable and valid self-report measure of the impact of spasticity on daily life in people with SCI, taking into account both the problematic and useful effects of spasticity.

Nonoperative management of spasticity in children

Central to the longitudinal management of childhood hypertonia are nonsurgical treatments. These include physical and occupational therapy, electrical stimulation, orthotics, botulium toxin, and drugs. This manuscripts reviews these treatment modalities as well as evaluation tools available to assess their impact on a child's hypertonia.

Oral baclofen and clonidine for treatment of spasticity in children

Few data exist in the literature to support the use of high dosages of oral baclofen and clonidine that are frequently required to treat children with spasticity. This study was a retrospective chart review of baclofen and clonidine dosages used in children diagnosed with cerebral palsy or traumatic brain injury. The primary objective was to calculate the mean dosages of baclofen and clonidine based on the duration of spasticity postinjury. Secondary objectives included determining correlations between dosage and age, injury type, location of spasticity, comorbid seizures, or concomitant antispasticity medications. Eighty-seven children receiving baclofen and/or clonidine were included in this study. Mean dosages of 40 mg/day (n = 86) and 0.4 mg/day (n = 31) were required for baclofen and clonidine, respectively. The maximum dosage was 240 mg/day for baclofen and 3.6 mg/day for clonidine. Duration postinjury, age, and concomitant antispasticity medications were the most predictive variables for baclofen dosage as a model (r = .522; P = .000). Duration postinjury and location of spasticity were the most predictive variables for clonidine dosage as a model (r = .523; P = .000). The average dosages of baclofen and clonidine used in this population of children with cerebral palsy or traumatic brain injury were similar to those reported in the literature, with higher maximum dosages found in this investigation.

Spasticity after spinal cord injury

Symptoms of spasticity are often experienced by individuals with spinal cord injury (SCI) following a period of spinal shock and, in many cases, these symptoms negatively affect quality of life. Despite its prevalence, spasticity as a syndrome in the SCI population is not always managed effectively. This is likely due to the fact that the syndrome can have various presentations, each with their own specific etiology. This overview summarizes the symptoms and pathophysiology of the various presentations of spasticity in the SCI population and discusses the currently accepted management techniques. There is a need for a better understanding of the syndrome of spasticity as well as the development of a valid and reliable assessment tool.

Chronic intrathecal baclofen treatment and withdrawal: I. Changes in ankle torque and hind limb posture in normal rats

This study evaluated reflex excitability and locomotor changes during chronic intrathecal infusion of the GABAb agonist baclofen (ITB) and its withdrawal, in the rat. We observed sustained velocity dependent decreases in ankle torque during four weeks of ITB treatment. These changes were correlated with a significant reduction of the EMG burst magnitude time locked to the dynamic phase of ankle dorsiflexion during the first ITB treatment week. However, a considerable recovery of EMG magnitude was observed during the third and fourth weeks of treatment. During baclofen withdrawal, significantly increased velocity dependent ankle torque was observed for 4 weeks. These increases in ankle torque were correlated with increased magnitudes of EMG time locked to the dynamic phase of ankle rotation. Measures of hind limb axis and base of support were obtained using analysis of footprints on a treadmill during ITB treatment and withdrawal periods. During ITB treatment and for up to 7 weeks of withdrawal, hindlimb axis and base of support were significantly altered compared with vehicle controls. These studies were performed to provide a foundation for evaluation of treatment and withdrawal in the setting of experimental chronic contusion spinal cord injury.

Pharmacotherapy of spasticity: oral medications and intrathecal baclofen

Spasticity is a common problem in children with neurologic impairment, particularly in those with cerebral palsy. Clinicians commonly make use of oral medications to attempt to reduce spasticity and increase function. Little has been published in the literature concerning the use of these medications in children and their effects on both muscle tone and function. This article is a review of the sites of action, side effects, and efficacy of benzodiazepines, baclofen, dantrolene sodium, alpha2-adrenergic agonists, and gabapentin. A brief review of intrathecal baclofen is included as well.