Gabapentin for the treatment of spasticity in patients with spinal cord injury

The Complex Role of Botulinum Toxin in Enhancing Goal Achievement for Post-Stroke Patients

INTRODUCTION

The rehabilitation medical team is responsible for the therapeutic management of post-stroke patients and, therefore, for the complex therapeutic approach of spasticity. Considering the generous arsenal at our disposal in terms of both pharmacological treatment, through the possibility of administering botulinum toxin to combat spasticity, and in terms of accurate assessment through developed functional scales such as the GAS (Goal Attainment Scale), one of our purposes is to monitor the parameters that influence the achievement of functional goals set by patients together with the medical team in order to render the patients as close as possible to achieving their proposed functional goals, thus enhancing their quality of life. By assessing and establishing statistical and clinical correlations between the GAS and quantifiable parameters related to the affected post-stroke upper limb, namely degree of spasticity, motor control, pain level and evolution of pain under treatment with BoNT-A (abobotulinum toxin A), and patients' overall response to BoNT-A treatment, we aim to quantify the improvement of the therapeutic management of post-stroke patients with spasticity and develop a more personalized and effective approach to their disability and impairment.

RESULTS AND DISCUSSIONS

The analysis concluded that there were two independent predictors of the Achieved GAS-T score (the study's endpoint parameter) motor control at any level of the upper limb and number of prior BoNT-A injections. The number of prior BoNT-A injections was an independent predictor of Achieved GAS-T score improvement but had no significant influence over Baseline GAS-T score. Enhancement in proximal and intermediate motor control showed a GAS score improvement of 3.3 points and a 0.93-point GAS score improvement for wrist motor control progress. From a separate viewpoint, patients with motor deficit on the left side have shown significantly greater improvement in Changed GAS-T scores by 2.5 points compared to patients with deficits on the right side; however, we note as a study limitation the fact that there was no statistical analysis over the dominant cerebral hemisphere of each patient.

CONCLUSIONS

Improvement in the Achieved GAS-T score means better achievement of patients' goals. Thus, after the BoNT- A intervention, at follow-up evaluation, GAS was found to be directly correlated with improvement in motor control of the affected upper limb. Mobility of the corresponding limb was enhanced by pain decrease during p-ROM (passive range of motion) and by amelioration of spasticity.

MATERIALS AND METHODS

We conducted an observational, non-randomized clinical study on 52 stroke patients, a representative sample of patients with post-stroke spasticity and disability from our neurological rehabilitation clinic, who have been treated and undergone a specific rehabilitation program in our tertiary diagnostic and treatment medical center, including BoNT-A focal treatment for spasticity in the affected upper limb. The primary objective of the study was to assess the influence of abobotulinum toxin A treatment on the Goal Attainment Scale. Secondary objectives of the study included the assessment of BoNT-A treatment efficacy on spasticity with the MAS (Modified Ashworth Scale), pain with the NRS (Numerical Rating Scale), and joint passive range of motion (p-ROM), identifying demographic, clinical, and pharmacological factors that influence the response to BoNT-A treatment, as well as to conduct a descriptive and exploratory analysis of the studied variables.

Gabapentin as part of a multimodal pain protocol for selective dorsal rhizotomy does not impact percentage of rootlets transected

PURPOSE

We aim to determine whether preoperatively initiated gabapentin for pain control impacts the percentage of rootlets cut during monitored, limited laminectomy selective dorsal rhizotomy (SDR) procedure.

METHODS

This retrospective cohort study includes participants with cerebral palsy who had SDR for treatment of spasticity between 2010 and 2019 at a single-institution tertiary care center. One-level laminectomy SDR aimed to evaluate the cauda equina roots from levels L2-S1 with EMG monitoring. Gabapentin titration began 3 weeks prior to SDR. Data was analyzed using simple linear regression. Thirty-one individuals met inclusion criteria. Mean age was 7 years, 4 months. Eighteen participants (58%) identified as male, 12 (39%) female, and one (3%) non-binary. Thirty (97%) had bilateral CP. Sixteen (52%) were GMFCS II, four (13%) GMFCS III, five (16%) GMFCS IV, and six (19%) GMFCS V.

RESULTS

Mean percentage of rootlets transected was 50.75% (SD 6.00, range 36.36-60.87). There was no relationship between the dose of gabapentin at time of SDR and percentage of rootlets cut with a linear regression slope of - 0.090 and an R2 of 0.012 (P = 0.56).

CONCLUSION

Results indicate that preoperative initiation of gabapentin did not impact the percentage of rootlets transected. Thus, gabapentin can be initiated prior to SDR at moderate dosages without impacting SDR surgical outcomes.

Biodegradable nanoparticles targeting circulating immune cells reduce central and peripheral sensitization to alleviate neuropathic pain following spinal cord injury

ABSTRACT

Neuropathic pain is a critical source of comorbidity following spinal cord injury (SCI) that can be exacerbated by immune-mediated pathologies in the central and peripheral nervous systems. In this article, we investigate whether drug-free, biodegradable, poly(lactide- co -glycolide) (PLG) nanoparticle treatment mitigates the development of post-SCI neuropathic pain in female mice. Our results show that acute treatment with PLG nanoparticles following thoracic SCI significantly reduces tactile and cold hypersensitivity scores in a durable fashion. Nanoparticles primarily reduce peripheral immune-mediated mechanisms of neuropathic pain, including neuropathic pain-associated gene transcript frequency, transient receptor potential ankyrin 1 nociceptor expression, and MCP-1 (CCL2) chemokine production in the subacute period after injury. Altered central neuropathic pain mechanisms during this period are limited to reduced innate immune cell cytokine expression. However, in the chronic phase of SCI, nanoparticle treatment induces changes in both central and peripheral neuropathic pain signaling, driving reductions in cytokine production and other immune-relevant markers. This research suggests that drug-free PLG nanoparticles reprogram peripheral proalgesic pathways subacutely after SCI to reduce neuropathic pain outcomes and improve chronic central pain signaling.

Treatment of spasticity

Spasticity is characterized by an enhanced size and reduced threshold for activation of stretch reflexes and is associated with "positive signs" such as clonus and spasms, as well as "negative features" such as paresis and a loss of automatic postural responses. Spasticity develops over time after a lesion and can be associated with reduced speed of movement, cocontraction, abnormal synergies, and pain. Spasticity is caused by a combination of damage to descending tracts, reductions in inhibitory activity within spinal cord circuits, and adaptive changes within motoneurons. Increased tone, hypertonia, can also be caused by changes in passive stiffness due to, for example, increase in connective tissue and reduction in muscle fascicle length. Understanding the cause of hypertonia is important for determining the management strategy as nonneural, passive causes of stiffness will be more amenable to physical rather than pharmacological interventions. The management of spasticity is determined by the views and goals of the patient, family, and carers, which should be integral to the multidisciplinary assessment. An assessment, and treatment, of trigger factors such as infection and skin breakdown should be made especially in people with a recent change in tone. The choice of management strategies for an individual will vary depending on the severity of spasticity, the distribution of spasticity (i.e., whether it affects multiple muscle groups or is more prominent in one or two groups), the type of lesion, and the potential for recovery. Management options include physical therapy, oral agents; focal therapies such as botulinum injections; and peripheral nerve blocks. Intrathecal baclofen can lead to a reduction in required oral antispasticity medications. When spasticity is severe intrathecal phenol may be an option. Surgical interventions, largely used in the pediatric population, include muscle transfers and lengthening and selective dorsal root rhizotomy.

Feasibility of gabapentin as an intervention for neurorecovery after an acute spinal cord injury: Protocol

Introduction

This protocol is describing the first ever prospective, mock-efficacy, dose exploration trial design testing the feasibility of administering gabapentin in the acute setting as an intervention for neurorecovery. Gabapentin is an FDA-approved medication for treating seizures and postherpetic neuralgia and is used broadly off-label for neuropathic pain management for many conditions, including spinal cord injury. Emerging data suggests that when given early after spinal cord injury onset and in low-medium doses, gabapentin may have properties that promote recovery of neurological function. The objective of this trial is to assess the feasibility of conducting an efficacy trial in which gabapentin is started early after injury, is restricted in its dose, and is not used for pain management.

Methods and analysis

Forty-two people aged 18 years or older with any level and any severity of spinal cord injury induced by a trauma will be enrolled, randomized, and have the first dose of study medication by 120 h post-injury onset. Participants will be randomly assigned to one of three groups: 600, 1,800 mg/day gabapentin, or placebo. Study medication will be given for a 90-day duration. Blinded assessments will be obtained at 7 days post-injury (baseline), 30 days post-injury (interim), after the 90-day treatment duration/approximately 3 months post-injury (end of treatment), and at 6 months post-injury (end of study). The key analysis parameters will evaluate feasibility of recruitment of target population, delivery of drug treatment protocol, maintenance of blinding, and retention of participants.

Discussion

Outputs from this trial will inform research and clinical practice on the effects of manipulating gabapentin for non-pain management purposes in the acute setting and will guide the development of a properly powered efficacy trial of gabapentin as an intervention for neurorecovery in spinal cord injury.

Ethics and dissemination

The study was approved by the MetroHealth Institutional Review Board (IRB21-00609) and registered at clinicaltrials.gov prior to enrolling any participants. Dissemination will include peer-reviewed publications, presentations at professional conferences and in the community, and through other healthcare and public venues.

Clinical trial registration

www.ClinicalTrials.gov, identifier: NCT05302999; protocol version 1.1 approved 05/23/2022.

Trial funding

National Institute on Disability, Independent Living and Rehabilitation Research.

The Role of Microglia in Modulating Neuroinflammation after Spinal Cord Injury

The pathobiology of traumatic and nontraumatic spinal cord injury (SCI), including degenerative myelopathy, is influenced by neuroinflammation. The neuroinflammatory response is initiated by a multitude of injury signals emanating from necrotic and apoptotic cells at the lesion site, recruiting local and infiltrating immune cells that modulate inflammatory cascades to aid in the protection of the lesion site and encourage regenerative processes. While peripheral immune cells are involved, microglia, the resident immune cells of the central nervous system (CNS), are known to play a central role in modulating this response. Microglia are armed with numerous cell surface receptors that interact with neurons, astrocytes, infiltrating monocytes, and endothelial cells to facilitate a dynamic, multi-faceted injury response. While their origin and essential nature are understood, their mechanisms of action and spatial and temporal profiles warrant extensive additional research. In this review, we describe the role of microglia and the cellular network in SCI, discuss tools for their investigation, outline their spatiotemporal profile, and propose translationally-relevant therapeutic targets to modulate neuroinflammation in the setting of SCI.

Flumazenil therapy for a gabapentin-induced coma: a case report

Background

Spasticity and neuropathic pain are common in patients after spinal cord injury and negatively affect patients’ quality of life. Gabapentin and baclofen are frequently used to treat these conditions. We present a flumazenil-reversed gabapentin-induced coma case, which, to our knowledge, is the second one described in scientific literature.

Case presentation

A 70-year-old Caucasian man was admitted to our neurorehabilitation ward following a fall with cervical trauma that resulted in immediate tetraplegia. During his stay, he suffered from lower limb pain, both neuropathic and due to severe spasticity. Gradual baclofen and gabapentin administration was prescribed, with reduction in both pain and spasticity. One morning, the patient was found unresponsive, with a Glasgow Coma Score of 3. Head computerized tomography, electrocardiogram, electroencephalogram, vital signs, blood tests, breathing, and blood oxygenation were normal. Renal and liver failure were ruled out. Intravenous 0.25 mg of flumazenil (Anexate) was administered, resulting in complete neurocognitive recovery with a Glasgow Coma Score of 15.

Discussion and conclusions

This case report highlights the importance of the individual response to certain pharmacological agents and suggests that further studies need to be conducted both on flumazenil and gabapentin pharmacodynamics to better understand their molecular–receptor activity, and on possible multiple flumazenil mechanisms of action, beyond its classical strict benzodiazepine antagonist action.

The Minimum Data Set: An Opportunity to Improve Spasticity Screening

Spasticity is a common movement disorder that arises from trauma or disease affecting the central nervous system. Untreated spasticity can result in limitations in completing activities of daily living, painful limb contractures, and other conditions associated with loss of mobility. In the long-term care setting, this treatable condition is prevalent, yet often unrecognized likely because of a lack of spasticity-trained practitioners. A recently published spasticity referral tool holds promise for addressing the underdiagnosis of spasticity in the long-term care population. The Minimum Data Set (MDS) would be an ideal mechanism for increasing the diagnosis and treatment of spasticity because it is a government-directed comprehensive screening tool that informs care plans for all residents residing in federally funded long-term care facilities. The MDS could easily integrate the published referral assessment to record the presence of spastic postures and muscle rigidity. We propose expanding the MDS to include 3 questions related to spasticity to improve the recognition and treatment of this prevalent and treatable condition.

Pharmacologic Treatment Tools: Systemic Medications and Toxins, Opportunities, and Pitfalls

Treatment of pathologic muscle overactivity associated with upper motor neuron syndrome can be multifaceted. One of the initial decisions to be made when formulating an overarching treatment plan is selecting a combination of strategies that is most applicable. Strategies may include physical interventions, such as stretching or splinting modalities, or surgery, whereas pharmacotherapeutic strategies encompass oral/systemic medications as well as agents, such as toxins and alcohols, used for focal chemodenervation. This article reviews the oral/systemic therapies as well as toxins that are used focally. Although medication can also be administered via intrathecal pumps, this treatment approach is discussed elsewhere.

Neuropathic Pain After Spinal Cord Injury: Challenges and Research Perspectives

Neuropathic pain is a debilitating consequence of spinal cord injury (SCI) that remains difficult to treat because underlying mechanisms are not yet fully understood. In part, this is due to limitations of evaluating neuropathic pain in animal models in general, and SCI rodents in particular. Though pain in patients is primarily spontaneous, with relatively few patients experiencing evoked pains, animal models of SCI pain have primarily relied upon evoked withdrawals. Greater use of operant tasks for evaluation of the affective dimension of pain in rodents is needed, but these tests have their own limitations such that additional studies of the relationship between evoked withdrawals and operant outcomes are recommended. In preclinical SCI models, enhanced reflex withdrawal or pain responses can arise from pathological changes that occur at any point along the sensory neuraxis. Use of quantitative sensory testing for identification of optimal treatment approach may yield improved identification of treatment options and clinical trial design. Additionally, a better understanding of the differences between mechanisms contributing to at- versus below-level neuropathic pain and neuropathic pain versus spasticity may shed insights into novel treatment options. Finally, the role of patient characteristics such as age and sex in pathogenesis of neuropathic SCI pain remains to be addressed.

Effects of pregabalin on brain edema, neurologic and histologic outcomes in experimental traumatic brain injury

Brain edema and increased intracranial pressure (ICP) are among the main causes of neurological disturbance and mortality following traumatic brain injury (TBI). Since pregabalin neuroprotective effects have been shown, this study was performed to evaluate the possible neuroprotective effects of pregabalin in experimental TBI of male rats. Adult male Wistar rats were divided into 4 groups: sham, vehicle, pregabalin 30 mg/kg and pregabalin 60 mg/kg. TBI was induced in vehicle and pregabalin groups by Marmarou method. Pregabalin was administered 30 min after TBI. Sham and vehicle groups received saline. Brain water and Evans blue content and histopathological changes were evaluated 24, 5 and 24 h after TBI, respectively. The ICP and neurological outcomes (veterinary coma scale, VCS) were recorded before, 1 h and 24 h post TBI. The results showed a significant reduction in brain water content and ICP, and a significant increase in VCS of pregabalin group (60 mg/kg) as compared to vehicle group (P < 0.05). Also, pregabalin reduced brain edema and apoptosis score as compared to vehicle group. Post TBI pregabalin administration revealed a delayed but significant improvement in ICP and neurological outcomes in experimental TBI. The underlying mechanism(s) was not determined and needs further investigation.

Therapeutics in the Management of Spasticity

Spasticity is commonly defined as a velocity-dependent increase in tonic stretch re flexes that results from a variety of disorders affecting the brain and spinal cord. Treat ment of spasticity is generally considered when the increase in tone interferes with functional activities, such as positioning, mobility, or daily cares, when it is painful, or when it leads to complications such as contractures or skin breakdown. This re view discusses the pathophysiology of spasticity and details the various treatments avail able, including physical and occupational therapy modalities, use of splints and or thoses, oral and intrathecal medications, nerve blocks, botulinum toxin injections, and orthopedic and neurosurgical interventions.

A Review of Spasticity Treatments: Pharmacological and Interventional Approaches

Spasticity is a velocity-dependent increase in muscle tone and uncontrolled, repetitive, involuntary contractions of skeletal muscles. Spasticity presents as upper motor neuron symptoms in patients with central nervous system pathology such as stroke, spinal cord injury, brain injury, or multiple sclerosis. As a result, a patient can have significant pain and limited mobility, which can lead to decreased quality of life and difficulty maintaining personal care. In this article we discuss mechanisms, indications, efficacy, and side effects of the most accepted current treatments. Currently available treatment options include oral medications and interventional procedures. Oral medications comprise centrally acting agents, such as baclofen, clonidine, and tizanidine, as well as anticonvulsants such as benzodiazepines and gabapentin and peripherally acting dantrolene. Interventional procedures include focal injections of botulinum toxin, phenol or alcohol, and an intrathecal baclofen pump. Surgical treatments include selective dorsal rhizotomy and neurectomy. We found that there are several treatments available with data to support their use, but many still need further research to prove their efficacy and develop optimal utilization.

Effects of gabapentin on muscle spasticity and both induced as well as spontaneous autonomic dysreflexia after complete spinal cord injury

We recently reported that the neuropathic pain medication, gabapentin (GBP; Neurontin), significantly attenuated both noxious colorectal distension (CRD)-induced autonomic dysreflexia (AD) and tail pinch-induced spasticity compared to saline-treated cohorts 2–3 weeks after complete high thoracic (T4) spinal cord injury (SCI). Here we employed long-term blood pressure telemetry to test, firstly, the efficacy of daily versus acute GBP treatment in modulating AD and tail spasticity in response to noxious stimuli at 2 and 3 weeks post-injury. Secondly, we determined whether daily GBP alters baseline cardiovascular parameters, as well as spontaneous AD events detected using a novel algorithm based on blood pressure telemetry data. At both 14 and 21 days after SCI, irrespective of daily treatment, acute GBP given 1 h prior to stimulus significantly attenuated CRD-induced AD and pinch-evoked tail spasticity; conversely, acute saline had no such effects. Moreover, daily GBP did not alter 24 h mean arterial pressure (MAP) or heart rate (HR) values compared to saline treatment, nor did it reduce the incidence of spontaneous AD events compared to saline over the three week assessment period. Power spectral density (PSD) analysis of the MAP signals demonstrated relative power losses in mid frequency ranges (0.2–0.8 Hz) for all injured animals relative to low frequency MAP power (0.02–0.08 Hz). However, there was no significant difference between groups over time post-injury; hence, GBP had no effect on the persistent loss of MAP fluctuations in the mid frequency range after injury. In summary, the mechanism(s) by which acute GBP treatment mitigate aberrant somatosensory and cardiophysiological responses to noxious stimuli after SCI remain unclear. Nevertheless, with further refinements in defining the dynamics associated with AD events, such as eliminating requisite concomitant bradycardia, the objective repeatability of automatic detection of hypertensive crises provides a potentially useful tool for assessing autonomic function pre- and post-SCI, in conjunction with experimental pharmacotherapeutics for neuropathic pain, such as GBP.

Latest approaches for the treatment of spasticity and autonomic dysreflexia in chronic spinal cord injury

Two of the most prevalent secondary complications following spinal cord injury (SCI), besides loss of function and/or sensation below the level of injury, are uncontrolled muscle spasticity and hypertensive autonomic dysreflexia. Despite the desires of the SCI community, there have been few advances in the treatment and/or management of these fundamental impediments to the quality of life associated with chronic SCI. Therefore, the purpose of this review is to focus on current drug treatment strategies that alleviate symptoms of spasticity and autonomic dysfunction. Subsequently, looking ahead, we discuss whether individuals suffering from autonomic dysreflexia and/or muscle spasms can take certain compounds that specifically and rapidly block the neurotransmission of pain into the injured spinal cord to get rapid relief for both aberrant reflexes for which painful stimuli below the level of SCI are common precipitants.

WITHDRAWN: Gabapentin for acute and chronic pain

BACKGROUND

February 2009: The authors are aware of unpublished trial data for Gabapentin which could affect the results of this review. This information together with that from trials published since 2005, will be considered when this review is updated in 2009.Anticonvulsant drugs have been used in the management of pain since the 1960s. The clinical impression is that they are useful for chronic neuropathic pain, especially when the pain is lancinating or burning.

OBJECTIVES

To evaluate the analgesic effectiveness and adverse effects of gabapentin for pain management in clinical practice.

SEARCH STRATEGY

Randomised trials of gabapentin in acute, chronic or cancer pain were identified by MEDLINE (1966 to Nov 2004), EMBASE (1994 to Nov 2004), SIGLE (1980 to Jan 2004) and the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 4, 2004). Additional studies were identified from the reference list of the retrieved papers, and by contacting investigators. Date of most recent search: January 2004.

SELECTION CRITERIA

Randomised trials reporting the analgesic effects of gabapentin in participants with subjective pain assessment as either the primary or a secondary outcome.

DATA COLLECTION AND ANALYSIS

Data were extracted by two independent review authors, and trials were quality scored. Numbers-needed-to-treat-to-benefit (NNTs) were calculated, where possible, from dichotomous data for effectiveness, adverse effects and drug-related study withdrawal.

MAIN RESULTS

Fourteen reports describing 15 studies of gabapentin were considered eligible (1468 participants). One was a study of acute pain. The remainder included the following conditions: post-herpetic neuralgia (two studies), diabetic neuropathy (seven studies), a cancer related neuropathic pain (one study) phantom limb pain (one study), Guillain Barré syndrome (one study), spinal chord injury pain (one study) and various neuropathic pains (one study).The study in acute post-operative pain (70 participants) showed no benefit for gabapentin compared to placebo for pain at rest.In chronic pain, the NNT for improvement in all trials with evaluable data is 4.3 (95% CI 3.5 to 5.7). Forty two percent of participants improved on gabapentin compared to 19% on placebo. The number needed to harm (NNH) for adverse events leading to withdrawal from a trial was not significant. Fourteen percent of participants withdrew from active arms compared to 10% in placebo arms. The NNH for minor harm was 3.7 (95% CI 2.4 to 5.4). The NNT for effective pain relief in diabetic neuropathy was 2.9 (95% CI 2.2 to 4.3) and for post herpetic neuralgia 3.9 (95% CI 3 to 5.7).

AUTHORS' CONCLUSIONS

There is evidence to show that gabapentin is effective in neuropathic pain. There is limited evidence to show that gabapentin is ineffective in acute pain.

Gabapentin for spasticity and autonomic dysreflexia after severe spinal cord injury

STUDY DESIGN

Using a complete transection spinal cord injury (SCI) model at the fourth thoracic vertebral level in adult rats, we evaluated whether blocking noxious stimuli below the injury diminishes abnormal somatic and autonomic motor reflexes, manifested in muscular spasticity and hypertensive autonomic dysreflexia, respectively. Gabapentin (GBP) is well tolerated and currently used to manage neuropathic pain in the SCI population; evidence suggests that it acts to decrease presynaptic glutamate release. As clinical evidence indicates that GBP may suppress muscular spasticity in the chronic SCI population, we hypothesized that preventing neurotransmission of noxious stimuli with GBP eliminates a critical physiological link to these distinct, debilitating SCI-induced secondary impairments.

OBJECTIVES

Behavioural assessments of tail muscle spasticity and mean arterial blood pressure responses to noxious somatic and/or visceral stimulation were used to test the effects of GBP on these abnormal reflexes.

SETTING

Lexington, Kentucky.

METHODS

We used femoral artery catheterization and radio-telemetric approaches to monitor blood pressure alterations in response to noxious colorectal distension (CRD) weeks after complete SCI.

RESULTS

At 2-3 weeks post-SCI, acute GBP administration (50 mg kg(-1), i.p.) significantly attenuated both autonomic dysreflexia and tail spasticity induced by noxious stimuli compared with saline-treated cohorts.

CONCLUSION

These results show, for the first time, that a single-pharmacological intervention, GBP, can effectively attenuate the manifestation of both muscular spasticity and autonomic dysreflexia in response to noxious stimuli.

Rehabilitation in practice: Spasticity management

This series of articles for rehabilitation in practice aims to cover a knowledge element of the rehabilitation medicine curriculum. Nevertheless they are intended to be of interest to a multidisciplinary audience. The competency addressed in this article is 'The trainee consistently demonstrates a knowledge of the pathophysiology of various specific impairments including spasticity'. Spasticity is an extremely common feature of chronic neurological conditions and, if badly managed, it can result in pain, contractures and pressure sores, all of which can impact on function. It is therefore essential that a multidisciplinary management strategy is in place to help the individual manage their particular situation through education with timely access to interventions including instigation of a physical management programme and medication such as baclofen, tizanidine, dantrolene, benzodiazepines and gabapentin. Further treatment options for focal spasticity are botulinum toxin and phenol nerve blocks or intrathecal baclofen or phenol for predominant lower limb spasticity. Ongoing assessment with the use of appropriate outcome measures can both guide choice of treatment and monitor efficacy.

Efficacy of pregabalin and gabapentin for neuropathic pain in spinal-cord injury: an evidence-based evaluation of the literature

BACKGROUND

Spinal-cord injury (SCI) is a leading cause of neuropathic pain (NP). Current pharmaceutical treatments for NP in SCI patients are not effective. Two promising options are gabapentin (GP) and pregabalin (PB). Their predominant mechanism of action is believed to be the inhibition of calcium currents, leading in turn to reduced neurotransmitter release and attenuation of postsynaptic excitability. This could explain much of their efficacy in the treatment of both seizure disorders and pain syndromes. However, evidence for their efficacy in attenuating NP of SCI is still controversial.

OBJECTIVE

To efficiently integrate valid information and provide a basis for rational decision making, through determining PB and GP efficacy in treating NP in SCI.

METHODS

Literature was systematically reviewed. Medline, Embase, CINAHL and Cochrane Database were searched using search terms 'gabapentin', 'pregabalin', 'neurontin', 'lyrica', 'neuropathic pain' and 'spinal-cord injury'. Studies were assessed independently by two authors.

RESULTS

Five studies were eligible for inclusion. Two of them studied PB and three GP. Both GP and PB appear to be efficacious for NP in SCI. A clear comparison between the two drugs could not be performed. The literature data suggest that PB is more efficacious than GP in many important variables for NP in SCI, although PB use is followed by more side effects than GP. PB reduced Visual Analogue Score (VAS) in both studies (P < 0.001 and P = 0.016). On the other hand, for GP a maximum dosage of 3,600 mg/day reduced VAS score (P = 0.000), whereas a maximum dosage of 1,200 mg/day failed to do so.

CONCLUSION

There is a lack of studies comparing GP and PB in treating NP in SCI. This systematic review indicates the possible efficacy of PB and GP in NP of SCI. Recommendations for future research to inform clinical practice should include cost-effectiveness studies and dose-response analysis in order to determine the schema employed and the duration of treatment.

Double-blind crossover trial of gabapentin in SPG4-linked hereditary spastic paraplegia

Patients with hereditary spastic paraplegia (HSP) are often treated with antispastic drugs to relieve symptoms but documentation is lacking. In this study, gabapentin was tested in a double-blind crossover trial on a group of patients with HSP and linkage to the SPG4 locus. There was no difference between periods with gabapentin and placebo treatment in clinical assessment, self-reported parameters or paired transcranial magnetic stimulation evaluation of motor cortical excitability.

Gabapentin for acute and chronic pain

BACKGROUND

Anticonvulsant drugs have been used in the management of pain since the 1960s. The clinical impression is that they are useful for chronic neuropathic pain, especially when the pain is lancinating or burning.

OBJECTIVES

To evaluate the analgesic effectiveness and adverse effects of gabapentin for pain management in clinical practice.

SEARCH STRATEGY

Randomised trials of gabapentin in acute, chronic or cancer pain were identified by MEDLINE (1966-Nov 2004), EMBASE (1994-Nov 2004), SIGLE (1980-Jan 2004) and the Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library Issue 4, 2004). Additional reports were identified from the reference list of the retrieved papers, and by contacting investigators. Date of most recent search: January 2004.

SELECTION CRITERIA

Randomised trials reporting the analgesic effects of gabapentin in patients, with subjective pain assessment as either the primary or a secondary outcome.

DATA COLLECTION AND ANALYSIS

Data were extracted by two independent reviewers, and trials were quality scored. Numbers-needed-to-treat (NNTs) were calculated, where possible, from dichotomous data for effectiveness, adverse effects and drug-related study withdrawal.

MAIN RESULTS

Fourteen reports describing 15 studies of gabapentin were considered eligible (1468 participants). One was a study of acute pain. The remainder included the following conditions: post-herpetic neuralgia (two studies), diabetic neuropathy (seven studies), a cancer related neuropathic pain (one study) phantom limb pain (one study), Guillain Barré syndrome (one study) , spinal chord injury pain (one study) and various neuropathic pains (one study). The study in acute post-operative pain (70 participants) showed no benefit for gabapentin compared to placebo for pain at rest. In chronic pain, the NNT for improvement in all trials with evaluable data is 4.3 (95%CI 3.5-5.7). Forty two percent of participants improved on gabapentin compared to 19% on placebo. The number needed to harm(NNH) for adverse events leading to withdrawal from a trial was not significant. Fourteen percent of participants withdrew from active arms compared to 10% in placebo arms. The NNH for minor harm was 3.7 (95% CI 2.4 to 5.4). The NNT for effective pain relief in diabetic neuropathy was 2.9 (95% CI 2.2 to 4.3) and for post herpetic neuralgia 3.9 (95% CI 3 to 5.7).

AUTHORS' CONCLUSIONS

There is evidence to show that gabapentin is effective in neuropathic pain. There is limited evidence to show that gabapentin is ineffective in acute pain.

Efectividad de la gabapentina en el tratamiento de la espasticidad: estudio aleatorizado, a doble ciego y controlado con placebo

BACKGROUND AND OBJECTIVE

We aimed to demonstrate the efficacy and safety of gabapentin for the treatment of spasticity in patients with upper motor neuron syndrome.

PATIENTS AND METHOD

Thirty patients with pyramidal-tract lesions were randomized to up to 3,600 mg/day of gabapentin (n = 15) or placebo (n = 15) in a double-blind, pilot 10-week trial. The primary efficacy variable was the Ashworth Scale score. Secondary variables included the Spasm Frequency Scale, maximal range of movement, H/M Amplitude Ratio, and the Barthel Index for quality of life. Adverse events were recorded. All data were analyzed on an intent-to-treat basis.

RESULTS

Demographic and baseline characteristics were similar between the 2 treatment groups. The gabapentin group showed significant improvement in Ashworth Scale total scores, and scores for individual affected muscle groups. Fifteen of the randomized patients had spasms; the total Spasm Frequency Scale score was not significantly different between groups. Nevertheless, when affected individual muscle groups were analyzed, a significant effect of gabapentin vs placebo was observed at all visits. Gabapentin did not modify the scores of the range of movement, the H/M Amplitude Ratio, or the Barthel Index tests. No gait or displacement impairment were seen during treatment with gabapentin. Related adverse events occurred less frequently in the gabapentin group, and fewer gabapentin patients withdrew because of adverse events.

CONCLUSIONS

Gabapentin demonstrated efficacy and safety at doses between 2,700 and 3,600 mg/day as a therapy for the spasticity associated with the upper motor neuron syndrome.

GABAB Receptors Do Not Mediate the Inhibitory Actions of Gabapentin on the Spinal Reflex in Rats

The clinical effectiveness of gabapentin for the treatment of epilepsy, spasticity, and neuropathic pain has been established. The mechanisms responsible for those actions, however, are still not clearly understood. We have recently demonstrated that gabapentin reduces the spinal reflex in rats via mechanisms that do not involve gamma-aminobutyric acid (GABA)A receptors. In the study, we attempted to explore the involvement of GABAB receptors in gabapentin-induced inhibition of the spinal reflexes in spinalized rats. Stimulation of the dorsal root at L5 elicited the segmental mono-(MSR) and polysynaptic reflex (PSR) in the ipsilateral ventral root. The microinjection of gabapentin (1.5 and 5 nmol) into the ventral horn reduced both MSR and PSR, whereas the injection into the dorsal horn only inhibited the PSR, indicating that systemic gabapentin inhibits the MSR at the ventral horn and it inhibits the PSR at both the ventral and dorsal horns. The GABAB-receptor antagonist CGP35348 (0.5 nmol) injected into the ventral horn antagonized the inhibition of the spinal reflexes by the GABAB-receptor agonist baclofen (i.v.) but not by gabapentin (i.v.). Thus, GABAB receptors do not appear to contribute to the gabapentin-induced inhibition of the spinal reflex.

Outcome Assessment for Spasticity Management in the Patient With Traumatic Brain Injury

The objective of this article was to (1) review the engineering and medical literature to structure the available information concerning the assessment of spasticity in the neurological population; (2) to discuss the strengths and weaknesses of the different methods currently in use in spasticity assessment; and (3) make recommendations for future efforts in spasticity outcome assessment. Spasticity textbooks, Web sites, and OVID, IEEE, and Medline searches from 1966 through 2003 of spasticity, quantitative measure, or outcome assessment in the rehabilitation population were used as data sources. Over 500 articles were reviewed. Articles that discussed outcome measures used to assess interventions and evaluation of spasticity were included. Authors reviewed the articles looking at inclusion criteria, data collection, methodology, assessment methods, and conclusions for validity and relevance to this article. Issues such as clinical relevance, real-world function and lack of objectivity, and time consumed during performance are important issues for spasticity assessment. Some measures such as the Ashworth Scale remain in common use secondary to ease of use despite their obvious functional limitations. More functional outcome goals are plagued by being more time consuming and a general inability to demonstrate changes after an intervention. This may be secondary to the other factors that combine with spasticity to cause dysfunction at that level. Quantitative metrics can provide more objective measurements but their clinical relevance is sometimes problematic. The assessment of spasticity outcome is still somewhat problematic. Further work is necessary to develop measures that have real-world functional significance to both the individuals being treated and the clinicians. A lack of objectivity is still a problem. In the future it is important for clinicians and the engineers to work together in the development of better outcome measures.

Gabapentin: pharmacology and its use in pain management

Although its exact mode of action is not known, gabapentin appears to have a unique effect on voltage-dependent calcium ion channels at the postsynaptic dorsal horns and may, therefore, interrupt the series of events that possibly leads to the experience of a neuropathic pain sensation. Gabapentin is especially effective at relieving allodynia and hyperalgesia in animal models. It has been shown to be efficacious in numerous small clinical studies and case reports in a wide variety of pain syndromes. Gabapentin has been clearly demonstrated to be effective for the treatment of neuropathic pain in diabetic neuropathy and postherpetic neuralgia. This evidence, combined with its favourable side-effect profile in various patient groups (including the elderly) and lack of drug interactions, makes it an attractive agent. Therefore, gabapentin should be considered an important drug in the management of neuropathic pain syndromes.

The biopsychosocial model and spinal cord injury

OBJECTIVE

To highlight the importance of taking the psychological, social and biological aspects into consideration when dealing with somatic complaints of spinal cord injured patients.

SETTING

Supra-regional Spinal Injury Unit in the UK.

STUDY DESIGN

Case study series.

MATERIAL AND METHODS

The somatic complaints of four patients with spinal cord injury were assessed and their relationship to psychological and social issues were correlated. Two patients suffered unexplained pain, another excessive spasm uncontrolled with intrathecal Baclofen pump and the fourth with several pressure sores, constipation and other physical problems. The impact of psychosocial issues on the somatic complaints were analysed.

RESULTS

In all four patients the resolution of their psychosocial issues resulted in significant gains vis-à-vis their somatic complaints.

CONCLUSION

Psychological and social issues of spinal injury patients could have a serious impact on the resolution of somatic complaints. It is important to take these into consideration in their treatment.

Management of spasticity, pain, and paroxysmal phenomena in multiple sclerosis

Multiple sclerosis (MS) is a disease with tremendous variability and innumerable symptoms. Among the more common symptoms is spasticity. Despite a lack of full knowledge of the physiology causing this phenomenon, successful treatments have been developed. Many of these have had a recent introduction. Pain and paroxysmal phenomena are surprisingly common in MS, but have not had the recognition their frequency deserves. It is not unusual to hear that they are rare in MS, but surprisingly they are all too common. Their management is changing as newer treatments are developed.

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.

Gabapentin for chronic pain in spinal cord injury: a case report

A 30-year-old white woman with an L1 complete spinal cord injury (SCI) secondary to a gunshot wound in 1985, presented to a chronic pain service for evaluation. She had a 13-year history of chronic lower extremity pain. She described her discomfort as "throbbing, aching, and stabbing." She had tried many different medications, including opioids, Tegretol, and tricyclic antidepressants, without success. During the evaluation process, she admitted to being "angry, frustrated, and anxious." She was diagnosed with central pain after SCI. She was placed on gabapentin 300 mg 3 times daily; within 1 week, her visual analog pain scale fell from 95 mm to 27 mm, and her McGill Short Form pain score fell from 13 to 3. Her mood also vastly improved. This case report suggests that gabapentin should be studied as a therapeutic option for treating central pain post-SCI and should be considered as a viable, well-tolerated, low-toxicity tool.

Gabapentin for essential tremor: a multiple-dose, double-blind, placebo-controlled trial

Essential tremor (ET) is a common movement disorder that often becomes refractory to conventional pharmacologic management. Open-label studies suggest that gabapentin is efficacious for ET, but the results of controlled trials have been mixed. To determine the efficacy and tolerability of gabapentin in ET, we conducted a double-blind, placebo-controlled, cross-over trial evaluating two doses (1800 mg per day and 3600 mg per day; N = 25). Patients on other ET medications were maintained on their concurrent medications for 3 months prior to study initiation and throughout the study. Twenty patients (mean age, 69.9 +/- 6.1 yrs) completed the study. Overall, patient global assessments (p <0.05), observed tremor scores (p <0.005), water pouring scores (p <0.05), and activities of daily living scores (p <0.005) significantly improved. Accelerometry scores, spirographs, and investigator global impression scores did not improve. The results were similar for high and low doses. Statistical regression models did not demonstrate any significant predictors for response. Gabapentin may be effective in some cases of ET.

Spasticity in spinal cord injury: self- and clinically rated intrinsic fluctuations and intervention-induced changes

OBJECTIVES

(1) To determine patterns of intrinsic fluctuations in spasticity, using repeated self-ratings, in subjects with spinal cord injury (SCI); and (2) To determine the relation between self-ratings of spasticity using a visual analogue scale (VAS) and clinical ratings of spasticity using the Modified Ashworth Scale (MAS) before and after spasticity-reducing treatment.

DESIGN

Part I: observational, prospective cross-sectional study; part II: experimental, prospective longitudinal study.

SETTING

Outpatient clinic of the Karolinska Hospital, Stockholm, Sweden.

PATIENTS

Forty-five persons with SCI (39 men, 6 women); mean age at injury, 26 yrs; mean time since injury, 11 yrs.

INTERVENTION

Repetitive passive movements of standardized range of motion in three different body positions, performed by two motorized tables.

MAIN OUTCOME MEASURES

VAS ratings of spasticity, every other hour when awake, and of movement-provoked spasticity, rated before and after each treatment session, and MAS ratings of movement-provoked spasticity, before and after each treatment session.

RESULTS

The spasticity of cervical SCI subjects fluctuated significantly (p < .05) during the day, unlike the spasticity of thoracic SCI subjects. Immediately after intervention with passive movements, spasticity ratings in thoracic motor complete SCI patients decreased by 11 to 14 mm (90%, p < .001) as self-rated on VAS and by 1 to 2 grades (50%, p < .001) as measured with MAS. A 30% (p < .018) decrease in VAS values of intrinsic pattern of spasticity was maintained over time when treatment was given regularly and was maintained for at least 1 week after discontinuation of treatment. VAS ratings correlated significantly with MAS ratings (r = .44 to .62, p < .001).

CONCLUSION

Repetitive passive movement intervention decreased spasticity when performed regularly, as assessed by VAS and MAS ratings. VAS and MAS ratings were significantly correlated. It is recommended that SCI patients repeatedly rate their spasticity to establish a baseline before and to track changes after interventions aimed at reducing spasticity. The time of day when spasticity is measured seems more important in cervically injured individuals, because of their more pronounced intrinsic fluctuations.

Gabapentin effect on spasticity in multiple sclerosis: a placebo-controlled, randomized trial

OBJECTIVE

To investigate the effect of gabapentin on subject self-report and physician-administered spasticity scales in individuals with multiple sclerosis.

DESIGN

Prospective, double-masked, placebo-controlled, crossover design.

SETTING

The Multiple Sclerosis Center at the Denver Veterans Affairs Medical Center.

INTERVENTION

Subjects were titrated to either 900 mg gabapentin orally three times a day or placebo over a 6-day period. Subjects underwent a 14-day washout and then were crossed over. No other changes were made to their medication regimen.

MAIN OUTCOME MEASURES

The outcome measures were divided into two categories: subject self-report scales physician-administered scales. Subject self-report scales included the spasm frequency scale, spasm severity scale, interference with function scale, painful spasm scale, and global assessment scale. Physician-administered scales included the Modified Ashworth Scale, clonus scale, deep tendon reflexes, plantar stimulation response, and the Kurtzke Expanded Disability Status (EDSS) Scale. Digit Span and Digit Symbol subtests of the WAIS-R Intelligence Scale were administered to assess for possible impaired concentration. The Fatigue Impact Scale was administered to assess for changes in fatigue. The adjective generation technique was administered to assess for alterations in mood.

RESULTS

A statistically significant reduction in the impairment of spasticity was found in the gabapentin-treated subjects compared with placebo as measured by the self-report scales of the spasm severity scale, interference with function scale, painful spasm scale, and global assessment scale and by the physician-administered scales of the Modified Ashworth and plantar stimulation response. No significant difference was noted in the Digit Span, Digit Symbol, adjective generation technique, and EDSS.

CONCLUSION

Gabapentin reduces the impairment of spasticity, compared with placebo, without the side effects of worsening concentration and fatigue.

Pharmacological interventions for spasticity following spinal cord injury

BACKGROUND

Spasticity is a major health problem for patients with a spinal cord injury (SCI) that limits patients' mobility and affects independence in activities of daily living and work. Spasticity may also cause pain, loss of range of motion, contractures, sleep disorders and impair ambulation in patients with an incomplete lesion. The effectiveness of available drugs is still uncertain and they may cause adverse effects. Assessing what works in this area is complicated by the lack of valid and reliable measurement tools. The aim of this systematic review is to critically appraise and summarise existing information of the effectiveness of available treatments and to identify areas where further research is needed.

OBJECTIVES

To assess the effectiveness and safety of Baclofen, Dantrolene, Tizanidine and any other drugs for the treatment of long term spasticity in SCI patients as well as the effectiveness and safety of different routes of administration of Baclofen.

SEARCH STRATEGY

We searched the Injuries Group specialised register, the Cochrane Controlled Trials Register, MEDLINE, EMBASE and CINHALH up to 1998. Drug companies and experts active in the area were also contacted.

SELECTION CRITERIA

All parallel and crossover RCTs including spinal cord injury patients complaining of "severe spasticity". Studies where less than 50% of patients had a spinal cord injury were excluded.

DATA COLLECTION AND ANALYSIS

Methodological quality of studies (allocation concealment, blinding, patients characteristics, inclusion and exclusion criteria; interventions; outcomes; lost to follow up) was independently assessed by two investigators. The heterogeneity among studies did not allow quantitative combination of results.

MAIN RESULTS

Nine out of 53 studies met the inclusion criteria. Study design was: 8 cross over, 1 parallel-group trial. Two studies (14 SCI patients), showed a significant effect of intrathecal baclofen in reducing spasticity (Ashworth Score and ADL performances), compared to placebo, without any side effect. The study comparing tizanidine to placebo (118 SCI patients) showed a significant effect of tizanidine in improving Ashworth Score but not in ADL performances. Tizanidine group reported significant rates of adverse effects (drowsiness, xerostomia). For the other drugs (Gabapentine, Clonidine, Diazepam, Amytal and oral Baclofen ) the results do not provide evidence for a clinical significant effectiveness.

REVIEWER'S CONCLUSIONS

There is insufficient evidence to assist clinicians in a rational approach to antispastic treatment for SCI. Further research is urgently needed to improve the scientific basis of patient care.

Spasticity after traumatic spinal cord injury: nature, severity, and location

OBJECTIVE

To assess spasticity in a prevalence population of persons with traumatic spinal cord injury (SCI), and determine the degree of correspondence between self-reported spasticity and investigator-elicited spasticity using the modified Ashworth scale.

DESIGN

Survey of a near total (88%) prevalence population.

SETTING

Outpatient clinic of a university hospital.

PATIENTS

A total of 354 individuals with SCI.

MAIN OUTCOME MEASURES

The survey includes self-reported symptoms, neurologic examination (American Spinal Injury Association [ASIA] classification), physical therapy examination, range of motion (ROM), and complications.

RESULTS

Presence of problematic spasticity was significantly correlated with cervical incomplete (ASIA B-D) injury. Reports of beneficial effects of spasticity were significantly less common in women. Self-reported problematic spasticity was significantly correlated with extensor spasticity. Spasticity was elicitable by movement provocation in 60% of the patients reporting spasticity. Significant correlations were found between elicitable spasticity and limited ROM.

CONCLUSION

Flexion, extension, and abduction movements performed with the patient placed in a standardized supine test position are suitable both for test of ROM and degree of spasticity. Spasticity was not elicitable by movement provocation on physical examination in 40% of the patients who reported spasticity, thus indicating that the patient's self-report is an important complement to the clinical assessment. A significant association between spasticity and contractures (reduced ROM) was seen.