Intraventricular baclofen as an alternative to intrathecal baclofen for intractable spasticity or dystonia: outcomes and technical considerations

Deep brain stimulation for pediatric pantothenate kinase-associated neurodegeneration with status dystonicus: A case report and literature review

BACKGROUND

Pantothenate kinase-associated neurodegeneration (PKAN) is a type of inherited metabolic disorder caused by mutation in the PANK2 gene. The metabolic disorder mainly affects the basal ganglia region and eventually manifests as dystonia. For patients of dystonia, their dystonic symptom may progress to life-threatening emergency--status dystonicus.

OBJECTIVE

We described a case of a child with PKAN who had developed status dystonicus and was successfully treated with deep brain stimulation (DBS). Based on this rare condition, we analysed the clinical features of PKAN with status dystonicus and reviewed the reasonable management process of this condition.

CONCLUSION

This case confirmed the rationality of choosing DBS for the treatment of status dystonicus. Meanwhile, we found that children with classic PKAN have a cluster of risk factors for developing status dystonicus. Once children diagnosed with similar neurodegenerative diseases are under status dystonicus, DBS can be active considered because it has showed high control rate of this emergent condition.

Intraventricular baclofen for palliative management of acquired generalized dystonia in pediatric patients: a case series and literature review

Dystonia represents a significant source of disability in children. Generalized dystonia, which involves multiple body regions, leads to impaired mobility and motor function, resulting in substantial challenges in daily activities. Surgical treatments are used when medical treatments fail. Intrathecal baclofen (ITB) or deep brain stimulations (DBS) are the most employed surgical therapies. When these options are not feasible or ineffective, some authors have explored the use of intraventricular baclofen (IVB). In this report, we present four cases of pediatric patients with generalized dystonia who underwent treatment with IVB, resulting in notable improvements. To further explore the potential of this treatment modality, we conducted a comprehensive literature review. The findings from our study provide a comprehensive overview that can guide palliative management in similar cases.

Perspectives on the pharmacological management of dystonia

Introduction: Treatment of dystonia is particularly complex due to various etiologies and heterogeneous clinical manifestation, as well as different degrees of disability. In absence of causative treatment, all symptomatic therapy should be predominantly tailored to ameliorate those symptoms (motor and non/motor) that mostly affect patients' daily life and regular activities. Many different treatment options, including oral medications, neurosurgical interventions, physical and occupational therapy are available in treatment of dystonia.Areas covered: The aim of this perspective is to point out different possibilities in pharmacological management of dystonic movements. Due to pure clinical presentation, the authors concentrate mainly on the isolated dystonias, which are presented solely as dystonic movements. Combined and complex dystonias are not instructive due to compound clinical presentation and consequently, complicated treatment. The article is based on a literature search from sources including PubMed, the Cochrane Library, Web of Science, PiCarta, and PsycINFO.Expert opinion: Although dystonia therapy should be adapted according to the individual needs, severity, age, type, symptoms distribution and acceptable side-effect profile, certain principles should be followed to reach the optimal result. Furthermore, the authors believe that a better understanding of the pathophysiology of dystonia will bring with it the development of new and improved treatment approaches and medications.

Treatment of Dystonia: Medications, Neurotoxins, Neuromodulation, and Rehabilitation

Dystonia is a complex disorder with numerous presentations occurring in isolation or in combination with other neurologic symptoms. Its treatment has been significantly improved with the advent of botulinum toxin and deep brain stimulation in recent years, though additional investigation is needed to further refine these interventions. Medications are of critical importance in forms of dopa-responsive dystonia but can be beneficial in other forms of dystonia as well. Many different rehabilitative paradigms have been studied with variable benefit. There is growing interest in noninvasive stimulation as a potential treatment, but with limited long-term benefit shown to date, and additional research is needed. This article reviews existing evidence for treatments from each of these categories. To date, there are many examples of incomplete response to available treatments, and improved therapies are needed.

Intrathecal Drug Delivery

Targeted intrathecal (IT) drug delivery systems (IDDS) are well established as an effective treatment of patients with chronic nonmalignant or malignant pain, and as a tool for management of patients with severe spasticity. The risk to benefit ratio of IDD makes it a relatively safe therapy for both cancer- and noncancer-related pain, but it is not free of risks, so it should be managed at specific centers. Recent technological advances, new therapeutic applications, reported complications, and the costs as well as maintenance required for this therapy require the need to stay up to date about new recommendations that may improve outcomes. This chapter reviews all technological issues regarding IDDS implantation with follow-up and pharmacological recommendations published during recent years that provide evidence-based decision-making process in the management of chronic pain and spasticity in patients.

Intrathecal Therapies

Intrathecal baclofen therapy is a well-established technique for spasticity management. This article briefly reviews the pharmacology of intrathecal baclofen as well as customary approach for utilization of this targeted drug delivery concept. Following these descriptions, four unusual presentations will be described, including the need for initial trialing, patient-directed boluses during chronic intrathecal baclofen therapy, use of medications other than baclofen for intrathecal therapy in spastic patients, and intraventricular baclofen delivery. These hypothetical cases are provided in an effort to expand the use of targeted drug delivery to larger population of spastic patients.

Dystonia

Dystonia is a neurological condition characterized by abnormal involuntary movements or postures owing to sustained or intermittent muscle contractions. Dystonia can be the manifesting neurological sign of many disorders, either in isolation (isolated dystonia) or with additional signs (combined dystonia). The main focus of this Primer is forms of isolated dystonia of idiopathic or genetic aetiology. These disorders differ in manifestations and severity but can affect all age groups and lead to substantial disability and impaired quality of life. The discovery of genes underlying the mendelian forms of isolated or combined dystonia has led to a better understanding of its pathophysiology. In some of the most common genetic dystonias, such as those caused by TOR1A, THAP1, GCH1 and KMT2B mutations, and idiopathic dystonia, these mechanisms include abnormalities in transcriptional regulation, striatal dopaminergic signalling and synaptic plasticity and a loss of inhibition at neuronal circuits. The diagnosis of dystonia is largely based on clinical signs, and the diagnosis and aetiological definition of this disorder remain a challenge. Effective symptomatic treatments with pharmacological therapy (anticholinergics), intramuscular botulinum toxin injection and deep brain stimulation are available; however, future research will hopefully lead to reliable biomarkers, better treatments and cure of this disorder.

Clinical Management of Dystonia in Childhood

Dystonia is one of the most frequent movement disorders in childhood. It can impede normal motor development and cause significant motor disability. The diagnostic evaluation of childhood dystonia is challenging due to the phenotypic variability and heterogeneous etiologies. Evidence to guide the diagnostic evaluation and treatment is limited. Assessment is primarily directed by clinical history and distinctive examination findings. Neuroimaging is typically necessary to evaluate for acquired or complex inherited dystonias. A trial of levodopa can be both diagnostic and therapeutic in children with dopa-responsive dystonia. However, for the majority of children with early-onset dystonia, treatment is symptomatic with varying efficacy. There is a paucity of therapeutic trials for childhood dystonia and most treatment recommendations are consensus or expert opinion driven. This review summarizes the available evidence and guidelines on the diagnostic evaluation and pharmacological treatment of childhood-onset dystonia and provides practical frameworks to approach both issues based on best evidence.

Medical treatment of dystonia

Therapeutic strategies in dystonia have evolved considerably in the past few decades. Three major treatment modalities include oral medications, botulinum toxin injections and surgical therapies, particularly deep brain stimulation. Although there has been a tremendous interest in the later two modalities, there are relatively few recent reviews of oral treatment. We review the medical treatment of dystonia, focusing on three major neurotransmitter systems: cholinergic, GABAergic and dopaminergic. We also provide a practical guide to medication selection, therapeutic strategy and unmet needs.

Advances in intrathecal drug delivery

PURPOSE OF REVIEW

Targeted intrathecal drug delivery systems (IDDS) are an option in algorithms for the treatment of patients with moderate-to-severe chronic refractory pain. This article is intended to review the literature regarding IDDS published over the last year, with special attention to the Polyanalgesic Consensus Conference 2012.

RECENT FINDINGS

The recommendations made by the Polyanalgesic Consensus Conference 2012 are reviewed. Separate considerations of intrathecal drug therapy for neuropathic and nociceptive pain syndromes and the new concept of 'microdosing' are discussed in this article.

SUMMARY

This review includes the recommendations for the use of IDDS, trialing, and recent reports of complications (especially, the occurrence of granulomas). In addition, the latest documents on cerebrospinal fluid and potential lines of future development are discussed.

Intrathecal baclofen for treating spasticity in children with cerebral palsy

BACKGROUND

Cerebral palsy is a disorder of movement and posture arising from a non-progressive lesion in the developing brain. Spasticity, a disorder of increased muscle tone, is the most common motor difficulty and is associated with activity limitation to varying degrees in mobility and self care.Oral baclofen, a gamma-aminobutyric acid (GABA) agonist, has been used in oral form to treat spasticity for some time, but it has a variable effect on spasticity and the dose is limited by the unwanted effect of excessive sedation. Intrathecal baclofen produces higher local concentrations in cerebrospinal fluid at a fraction of the equivalent oral dose and avoids this excessive sedation.

OBJECTIVES

To determine whether intrathecal baclofen is an effective treatment for spasticity in children with cerebral palsy.

SEARCH METHODS

We searched the CENTRAL, MEDLINE, EMBASE and CINAHL databases, handsearched recent conference proceedings, and communicated with researchers in the field and pharmaceutical and drug delivery system companies.

SELECTION CRITERIA

We included studies which compared the effect of intrathecal baclofen treatment on spasticity, gross motor function or other areas of function with controls.

DATA COLLECTION AND ANALYSIS

Two authors selected studies, two authors extracted data and two authors assessed the methodological quality of included studies.

MAIN RESULTS

Six studies met the inclusion criteria. The data obtained were unsuitable for the conduct of a meta-analysis; we have completed a qualitative summary.All studies were found to have high or unclear risk of bias in some aspects of their methodology.Five of the six studies reported data collected in the randomised controlled phase of the study. A sixth study did not report sufficient results to determine the effect of intrathecal baclofen versus placebo. Of these five studies, four were conducted using lumbar puncture or other short-term means of delivering intrathecal baclofen. One study assessed the effectiveness of implantable intrathecal baclofen pumps over six months.The four short-term studies demonstrated that intrathecal baclofen therapy reduces spasticity in children with cerebral palsy. However, two of these studies utilised inappropriate techniques for statistical analysis of results. The single longer-term study demonstrated minimal reduction in spasticity with the use of intrathecal baclofen therapy.One of the short-term studies and the longer term study showed improvement in comfort and ease of care. The longer term study found a small improvement in gross motor function and also in some domains of health-related quality of life.Some caution is required in interpreting the findings of the all the studies in the review due to methodological issues. In particular, there was a high risk of bias in the methodology of the longer term study due to the lack of placebo use in the control group and the absence of blinding to the intervention after randomisation for both participants and investigators.

AUTHORS' CONCLUSIONS

There is some limited short-term evidence that intrathecal baclofen is an effective therapy for reducing spasticity in children with cerebral palsy. The effect of intrathecal baclofen on long-term spasticity outcomes is less certain.The validity of the evidence for the effectiveness of intrathecal baclofen in treating spasticity in children with cerebral palsy from the studies in the review is constrained by the small sample sizes of the studies and methodological issues in some studies.Spasticity is a impairment in the domain of body structure and function. Consideration must also be given to the broader context in determining whether intrathecal baclofen therapy is effective. The aim of therapy may be, for example, to improve gross motor function, to increase participation at a social role level, to improve comfort, to improve the ease of care by others or to improve the overall quality of life of the individual. Intrathecal baclofen may improve gross motor function in children with cerebral palsy, but more reliable evidence is needed to determine this.There is some evidence that intrathecal baclofen improves ease of care and the comfort and quality of life of the individuals receiving it, but again small sample sizes and methodological issues in the studies mean that these results should be interpreted with caution.Further evidence of the effectiveness of intrathecal baclofen for treating spasticity, increasing gross motor function and improving comfort, ease of care and quality of life is needed from other investigators in order to validate these results.The short duration of the controlled studies included in this review did not allow for the exploration of questions regarding whether the subsequent need for orthopaedic surgery in children receiving intrathecal baclofen therapy is altered, or the safety and the economic implications of intrathecal baclofen treatment when long-term therapy is administered via an implanted device. Controlled studies are not the most appropriate study design to address these questions, cohort studies may be more appropriate.

Intrathecal Baclofen therapy in Germany: Proceedings of the IAB-Interdisciplinary Working Group for Movement Disorders Consensus Meeting

Continuous intrathecal Baclofen application (ITB) through an intracorporeal pump system is widely used in adults and children with spasticity of spinal and supraspinal origin. Currently, about 1200 new ITB pump systems are implanted in Germany each year. ITB is based on an interdisciplinary approach with neurologists, rehabilitation specialists, paediatricians and neurosurgeons. We are presenting the proceedings of a consensus meeting organised by IAB-Interdisciplinary Working Group for Movement Disorders. The ITB pump system consists of the implantable pump with its drug reservoir, the refill port, an additional side port and a flexible catheter. Non-programmable pumps drive the Baclofen flow by the reservoir pressure. Programmable pumps additionally contain a radiofrequency control unit, an electrical pump and a battery. They have major advantages during the dose-finding phase. ITB doses vary widely between 10 and 2000 μg/day. For spinal spasticity, they are typically in the order of 100-300 μg/day. Hereditary spastic paraplegia seems to require particularly low doses, while dystonia and brain injury require particularly high ones. Best effects are documented for tonic paraspasticity of spinal origin and the least effects for phasic muscle hyperactivity disorders of supraspinal origin. Oral antispastics are mainly effective in mild spasticity. Botulinum toxin is most effective in focal spasticity. Myotomies and denervation operations are restricted to selected cases of focal spasticity. Due to its wide-spread distribution within the cerebrospinal fluid, ITB can tackle wide-spread and severe spasticity.

Indwelling intrathecal catheter with subcutaneous abdominal reservoir: a viable baclofen delivery system in severely cachectic patients

Intrathecal baclofen (ITB) is a reversible treatment that reduces muscle tone to ameliorate spasticity and dystonia in patients with cerebral palsy (CP). The resulting decrease in energy expenditure allows patients to gain much-needed weight, albeit temporarily. Modern techniques require sufficient abdominal musculature and subcutaneous fat to permit the implantation of an indwelling pump. In patients with extremely low muscle bulk, visceral pumps may be impractical or impossible, with increased risks of dehiscence and infection. The authors describe a variation of the classical procedure in a young patient with severe cachexia. A 10-year-old boy with spastic-dystonic quadriplegic CP was admitted to the neuromedical unit. Numerous drug trials had failed, and surgical intervention was deemed necessary but was complicated by his cachectic body habitus. The authors inserted a lumbar intrathecal catheter and subcutaneously tunneled it to the anterolateral abdomen, where it was connected to a subcutaneous injection port. Baclofen was continuously infused into the subcutaneous port using a noncoring needle connected to an external pump. The needle and line were changed every 5 days to minimize the risk of sepsis. Although other techniques, such as intraventricular baclofen delivery, have been described, these are largely dependent upon sufficient musculature to support a visceral pump. A subcutaneous injection port system represents an alternative approach that reduces the risk of sepsis and may be better tolerated in cachectic patients.

Intrathecal delivery of analgesics

Targeted intrathecal (IT) drug delivery systems (IDDS) are an option in algorithms for the treatment of patients with moderate to severe chronic refractory pain when more conservative options fail. This therapy is well established and supported by several publications. It has shown efficacy and is an important tool for the treatment of spasticity, and both cancer and nonmalignant pain. Recent technological advances, new therapeutic applications, reported complications, and the costs as well as maintenance required for this therapy require the need to stay up-to-date about new recommendations that may improve outcomes. This chapter reviews all technological issues regarding IDDS implantation with follow-up, and pharmacological recommendations published during recent years that provide evidence-based decision making process in the management of chronic pain and spasticity in patients.

Treatment of dystonia

Selecting the appropriate treatment for dystonia begins with proper classification of disease based on age, distribution, and underlying etiology. The therapies available for dystonia include oral medications, botulinum toxin, and surgical procedures. Oral medications are generally reserved for generalized and segmental dystonia. Botulinum toxin revolutionized the treatment of focal dystonia when it was introduced for therapeutic purposes in the 1980s. Surgical procedures are available for medication-refractory dystonia, markedly affecting an individual's quality of life.

Role of Catheter's Position for Final Results in Intrathecal Drug Delivery. Analysis Based on CSF Dynamics and Specific Drugs Profiles

Intrathecal drug delivery is an effective and safe option for the treatment of chronic pathology refractory to conventional pain therapies. Typical intrathecal administered drugs are opioids, baclofen, local anesthetics and adjuvant medications. Although knowledge about mechanisms of action of intrathecal drugs are every day more clear many doubt remain respect the correct location of intrathecal catheter in order to achieve the best therapeutic result. We analyze the factors that can affect drug distribution within the cerebrospinal fluid. Three categories of variables were identified: drug features, cerebrospinal fluid (CSF) dynamics and patients features. First category includes physicochemical properties and pharmacological features of intrathecal administered drugs with special attention to drug lipophilicity. In the second category, the variables in CSF flow, are considered that can modify the drug distribution within the CSF with special attention to the new theories of liquoral circulation. Last category try to explain inter-individual difference in baclofen response with difference that are specific for each patients such as the anatomical area to treat, patient posture or reaction to inflammatory stimulus. We conclude that a comprehensive evaluation of the patients, including imaging techniques to study the anatomy and physiology of intrathecal environment and CSF dynamics, could become essential in the future to the purpose of optimize the clinical outcome of intrathecal therapy.