Prevalence of Spasticity and Below-Level Neuropathic Pain Related to Spinal Cord Injury Level and Damage to the Lower Spinal Segments

Intrathecal baclofen therapy for spasticity in a person with spinal cord injury and end-stage renal disease dependent on hemodialysis: a case report

INTRODUCTION

Spasticity is one of the most common secondary complications following a spinal cord injury (SCI), which can significantly debilitate a patient irrespective of the severity of the injury. Intrathecal baclofen therapy can effectively reduce global spasticity in bilateral lower extremities at lower doses and allows precise dose titration to manage spasticity optimally. In complex patients with spasticity and multiple medical comorbidities, multidisciplinary teamwork is required to assess ITB safety and deliver timely intervention to prevent secondary complications of spasticity and improve quality of life.

CASE PRESENTATION

A 61-year-old African American male with multiple comorbidities, including end-stage renal disease (ESRD) requiring dialysis sustained non-traumatic SCI due to epidural abscess resulting in paraplegia and severe debilitating spasticity. Spasticity gradually worsened and interfered with his ability to achieve independence with functional activities appropriate for his neurological level of injury. A multidisciplinary team approach in this complex case resulted in a successful ITB trial and subsequent ITB implantation, resulting in reduced spasticity and improved quality of life. To our knowledge, this is the first case report of the administration of intrathecal baclofen pump therapy in a person with SCI and end-stage renal disease (ESRD) dependent on hemodialysis.

DISCUSSION

ITB therapy can be safely delivered in a person with SCI and multiple medical comorbidities, including ESRD, dependent on hemodialysis to manage spasticity. However, a careful evaluation and discussion among the multidisciplinary team managing the patient's morbidities and patient is required to assess the risks and benefits of ITB therapy to allow the patient to make an informed decision.

Modern advances in spinal cord regeneration: hydrogel combined with neural stem cells

Severe spinal cord injuries (SCI) lead to loss of functional activity of the body below the injury site, affect a person's ability to self-care and have a direct impact on performance. Due to the structural features and functional role of the spinal cord in the body, the consequences of SCI cannot be completely overcome at the expense of endogenous regenerative potential and, developing over time, lead to severe complications years after injury. Thus, the primary task of this type of injury treatment is to create artificial conditions for the regenerative growth of damaged nerve fibers through the area of the SCI. Solving this problem is possible using tissue neuroengineering involving the technology of replacing the natural tissue environment with synthetic matrices (for example, hydrogels) in combination with stem cells, in particular, neural/progenitor stem cells (NSPCs). This approach can provide maximum stimulation and support for the regenerative growth of axons of damaged neurons and their myelination. In this review, we consider the currently available options for improving the condition after SCI (use of NSC transplantation or/and replacement of the damaged area of the SCI with a matrix, specifically a hydrogel). We emphasise the expediency and effectiveness of the hydrogel matrix + NSCs complex system used for the reconstruction of spinal cord tissue after injury. Since such a complex approach (a combination of tissue engineering and cell therapy), in our opinion, allows not only to creation of conditions for supporting endogenous regeneration or mechanical reconstruction of the spinal cord, but also to strengthen endogenous regeneration, prevent the spread of the inflammatory process, and promote the restoration of lost reflex, motor and sensory functions of the injured area of spinal cord.

Improvement in Quality-of-Life-Related Outcomes Following Treatment with IncobotulinumtoxinA in Adults with Limb Spasticity: A Pooled Analysis

A strong correlation has been reported between patient-reported quality of life (QoL) and the investigator-rated Disability Assessment Scale (DAS) in patients with spasticity. The current analysis evaluates the effect of incobotulinumtoxinA on QoL-related outcomes (limb position abnormality, as well as dressing- and hygiene-related disability, measured with the DAS) in adults with upper limb spasticity, using pooled data from six studies. Separate analyses for each DAS domain were performed using data from patients with disabilities for that domain (DAS score ≥1). Results showed that a significantly greater proportion of incobotulinumtoxinA-treated compared with placebo-treated patients achieved a ≥1-point reduction from baseline in each of the DAS domains (improvement) 4 weeks after the first injection. The benefits of incobotulinumtoxinA were observed regardless of the baseline severity of DAS impairment and of the time elapsed since stroke. The effects of incobotulinumtoxinA 4 weeks after injection were maintained or enhanced over multiple injection cycles for all three DAS domains, supporting the use of repeated injection cycles to provide sustained QoL benefit. IncobotulinumtoxinA represents an important treatment option to achieve better QoL-related outcomes for patients with upper limb spasticity, irrespective of the duration of their condition.

Neuronal differentiation and inhibition of glial differentiation of murine neural stem cells by pHPMA hydrogel for the repair of injured spinal cord

Currently, several therapeutic methods of treating the effects of spinal cord injury (SCI) are being considered. On the one hand, transplantation of stem cells (SCs), in particular, neural stem/progenitor cells (NSPCs), is promising, as these cells have the potential to differentiate into nervous tissue cells, able to enhance endogenous regeneration and prevent the development of inflammatory processes. On the other hand, it is quite promising to replace the damaged nervous tissue with synthetic matrices, in particular hydrogels, which can create artificial conditions for the regenerative growth of injured nerve fibers through the spinal cord injury area, i.e. stimulate and support axonal regeneration and myelination. In this work, we combined both of these novel approaches by populating (injecting or rehydrating) a heteroporous pHPMA hydrogel (NeuroGel) with murine hippocampal NSPCs. Being inside the hydrogel (10 days of cultivation), NSPCs were more differentiated into neurons: 19.48% ± 1.71% (the NSPCs injection into the hydrogel) and 36.49% ± 4.20% (the hydrogel rehydration in the NSPCs suspension); in control cultures, the level of differentiation in neurons was only 2.40% ± 0.31%. Differentiation of NSPCs into glial cells, in particular into oligodendrocyte progenitor cells, was also observed - 8.89% ± 2.15% and 6.21% ± 0.80% for injection and rehydration variants, respectively; in control - 28.75% ± 2.08%. In the control NSPCs culture, there was a small number of astrocytes - 2.11% ± 0.43%. Inside the hydrogel, NSPCs differentiation in astrocytes was not observed. In vitro data showed that the hydrogel promotes the differentiation of NSPCs into neurons, and inhibits the differentiation into glial cells. And in vivo showed post-traumatic recovery of rat spinal cord tissue after injury followed by implantation of the hydrogel+NSPCs complex (approximately 7 months after SCI). The implant area was closely connected with the recipient tissue, and the recipient cells freely grew into the implant itself. Inside the implant, a formed dense neuronal network was visible. In summary, the results are primarily an experimental ground for further studies of implants based on pHPMA hydrogel with populated different origin SCs, and the data also indicate the feasibility and efficiency of using an integrated approach to reduce possible negative side effects and facilitate the rehabilitation process after a SCI.

Bumetanide increases postsynaptic inhibition after chronic SCI and decreases presynaptic inhibition with step-training

Current anti-spastic medication significantly compromises motor recovery after spinal cord injury (SCI), indicating a critical need for alternative interventions. Because a shift in chloride homeostasis decreases spinal inhibition and contributes to hyperreflexia after SCI, we investigated the effect of bumetanide, an FDA-approved sodium-potassium-chloride intruder (NKCC1) antagonist, on presynaptic and postsynaptic inhibition. We compared its effect with step-training as it is known to improve spinal inhibition by restoring chloride homeostasis. In SCI rats, a prolonged bumetanide treatment increased postynaptic inhibition but not presynaptic inhibition of the plantar H-reflex evoked by posterior biceps and semitendinosus (PBSt) group I afferents. By using in vivo intracellular recordings of motoneurons, we further show that a prolonged bumetanide increased postsynaptic inhibition by hyperpolarizing the reversal potential for inhibitory postsynaptic potentials (IPSPs) after SCI. However, in step-trained SCI rats an acute delivery of bumetanide decreased presynaptic inhibition of the H-reflex, but not postsynaptic inhibition. These results suggest that bumetanide might be a viable option to improve postsynaptic inhibition after SCI, but it also decreases the recovery of presynaptic inhibition with step-training. We discuss whether the effects of bumetanide are mediated by NKCC1 or by off-target effects. KEY POINTS: After spinal cord injury (SCI), chloride homeostasis is dysregulated over time in parallel with the decrease in presynaptic inhibition of Ia afferents and postsynaptic inhibition of motoneurons, and the development of spasticity. While step-training counteracts these effects, it cannot always be implemented in the clinic because of comorbidities. An alternative intervention is to use pharmacological strategies to decrease spasticity without hindering the recovery of motor function with step-training. Here we found that, after SCI, a prolonged bumetanide (an FDA-approved antagonist of the sodium-potassium-chloride intruder, NKCC1) treatment increases postsynaptic inhibition of the H-reflex, and it hyperpolarizes the reversal potential for inhibitory postsynaptic potentials in motoneurons. However, in step-trained SCI, an acute delivery of bumetanide decreases presynaptic inhibition of the H-reflex, but not postsynaptic inhibition. Our results suggest that bumetanide has the potential to decrease spastic symptoms related to a decrease in postsynaptic but not presynaptic inhibition after SCI.

Prevalence of spasticity in humans with spinal cord injury with different injury severity

Spasticity is one of the most common symptoms manifested following spinal cord injury (SCI). The aim of this study was to assess spasticity in individuals with subacute and chronic SCI with different injury severity, standardizing the time and assessments of spasticity. We tested 110 individuals with SCI classified by the American Spinal Injury Association Impairment Scale (AIS) as either motor complete (AIS A and B; subacute, n = 25; chronic, n = 33) or motor incomplete (AIS C and D; subacute, n = 23; chronic, n = 29) at a similar time after injury (subacute, ∼1 mo after injury during inpatient rehabilitation and chronic, ≥1 yr after injury) using clinical (modified Ashworth scale) and kinematic (pendulum test) outcomes to assess spasticity in the quadriceps femoris muscle. Using both methodologies, we found that among individuals with subacute motor complete injuries, only a minority showed spasticity, whereas the majority exhibited no spasticity. This finding stands in contrast to individuals with subacute motor incomplete injury, where both methodologies revealed that a majority exhibited spasticity, whereas a minority exhibited no spasticity. In chronic injuries, most individuals showed spasticity regardless of injury severity. Notably, when spasticity was present, its magnitude was similar across injury severity in both subacute and chronic injuries. Our results suggest that the prevalence, not the magnitude, of spasticity differs between individuals with motor complete and incomplete SCI in the subacute and chronic stages of the injury. We thus argue that considering the "presence of spasticity" might help the stratification of participants with motor complete injuries for clinical trials.NEW & NOTEWORTHY The prevalence of spasticity in humans with SCI remains poorly understood. Using kinematic and clinical outcomes, we examined spasticity in individuals with subacute and chronic injuries of different severity. We found that spasticity in the quadriceps femoris muscle was more prevalent among individuals with subacute motor incomplete than in those with motor complete injuries. However, in a different group of individuals with chronic injuries, no differences were found in the prevalence of spasticity across injury severity.

Phenotypes of Motor Deficit and Pain after Experimental Spinal Cord Injury

Motor disability is a common outcome of spinal cord injury (SCI). The recovery of motor function after injury depends on the severity of neurotrauma; motor deficit can be reversible, at least partially, due to the innate tissue capability to recover, which, however, deteriorates with age. Pain is often a comorbidity of injury, although its prediction remains poor. It is largely unknown whether pain can attend motor dysfunction. Here, we implemented SCI for modelling severe and moderate neurotrauma and monitored SCI rats for up to 5 months post-injury to determine the profiles of both motor deficit and nociceptive sensitivity. Our data showed that motor dysfunction remained persistent after a moderate SCI in older animals (5-month-old); however, there were two populations among young SCI rats (1 month-old) whose motor deficit either declined or exacerbated even more over 4–5 weeks after identical injury. All young SCI rats displayed changed nociceptive sensitivity in thermal and mechanical modalities. The regression analysis of the changes revealed a population trend with respect to hyper- or hyposensitivity/motor deficit. Together, our data describe the phenotypes of motor deficit and pain, the two severe complications of neurotrauma. Our findings also suggest the predictability of motor dysfunction and pain syndromes following SCI that can be a hallmark for long-term rehabilitation and recovery after injury.

Spasticity Management after Spinal Cord Injury: The Here and Now

Spasticity is a common comorbidity of spinal cord injury (SCI) that is characterized by velocity dependent tone and spasms manifested by uninhibited reflex activity of muscles below the level of injury. For some, spasticity can be beneficial and facilitate functional standing, transfers, and some activities of daily living. For others, it may be problematic, painful, and interfere with mobility and function. This manuscript will address the anatomy and physiology of neuromuscular reflexes as well as the pathophysiology that occurs after SCI. Spasticity assessment will be discussed in terms of clinical history and findings on physical examinations, including responses to passive and active movement, deep tendon reflexes, and other long tract signs of upper motor neuron injury, as well as gait and function. Management strategies will be discussed including stretch, modalities, pharmacotherapy, neurolysis, and surgical options.

Effects of whole-body vibration on neuropathic pain and the relationship between pain and spasticity in persons with spinal cord injury

OBJECTIVE

Whole-body vibration (WBV) appears to modulate reflex hyperexcitability and spasticity. Due to common underlying neural mechanisms between spasticity and neuropathic pain, WBV may also reduce chronic pain after spinal cord injury (SCI). Our objective was to determine whether there are dose-related changes in pain following WBV and to examine the relationships between neuropathic pain and reflex excitability.

STUDY DESIGN

Secondary analysis of a sub-population (participants with neuropathic pain, n = 16) from a larger trial comparing the effects of two different doses of WBV on spasticity in persons with SCI.

SETTING

Hospital/Rehabilitation Center in Atlanta, GA, USA.

METHODS

Participants were randomized to 8-bout or 16-bout WBV groups. Both groups received ten sessions of sham intervention, followed by ten sessions of WBV. Primary measures included the Neuropathic Pain Symptom Inventory (NPSI) for pain symptom severity and H-reflex paired-pulse depression (PPD) for reflex excitability.

RESULTS

Mean change in NPSI scores were not significantly different between the groups (7 ± 6; p = 0.29; ES = 0.57); however, 8-bouts of WBV were consistently beneficial for participants with high neuropathic pain symptom severity (NPSI total score >30), while 16-bouts of WBV appeared to increase pain in some individuals with high NPSI scores. A baseline NPSI cut score of 30 predicted PPD response (sensitivity = 1.0, specificity = 0.83), with higher NPSI scores associated with decreased PPD in response to WBV.

CONCLUSIONS

WBV in moderate doses appears to decrease neuropathic pain symptoms and improve reflex modulation. However, at higher doses neuropathic pain symptoms may be aggravated. Lower baseline NPSI scores were associated with improved reflex modulation.