The impact of early spasticity on the intensive functional rehabilitation phase and community reintegration following traumatic spinal cord injury

Are early-onset spasms predictive of poor neurological recovery after traumatic spinal cord injury?

CONTEXT

Following spinal cord injury (SCI), early spasms are associated with decreased functional recovery. It has also been hypothesized that early spasticity might sign underlying maladaptive neuroplasticity, which could translate in worse neurological outcomes.

OBJECTIVE

In this context, this paper aims to evaluate if early-onset spasms are also associated with neurological outcomes after SCI.

METHODS

A retrospective review of 196 cases from a prospective SCI database was conducted. The presence of early spasms during the acute hospitalization was assessed by a single physiatrist. The characteristics and long-term neurological outcomes of individuals with and without early spasms were first compared. Multivariate regression analyses were then performed to determine the relationship between early spasms and neurological outcomes.

RESULTS

30.1% (N = 59) of patients presented early spasms. These patients had several distinguishing characteristics including higher odds of tetraplegia (vs. paraplegia) and more severe injuries. At the bivariate level, patients with early spasms had higher odds of improving at least 1 AIS grade between baseline and follow-up. However, this was not significant at the multivariate level.

CONCLUSIONS

Early spasms are not significantly associated with poorer neurological outcomes, contrasting with the unwritten consensus that early spasticity translates maladaptive neuroplasticity.

Muscle Spasms after Spinal Cord Injury Stem from Changes in Motoneuron Excitability and Synaptic Inhibition, Not Synaptic Excitation

Muscle spasms are common in chronic spinal cord injury (SCI), posing challenges to rehabilitation and daily activities. Pharmacological management of spasms mostly targets suppression of excitatory inputs, an approach known to hinder motor recovery. To identify better targets, we investigated changes in inhibitory and excitatory synaptic inputs to motoneurons as well as motoneuron excitability in chronic SCI. We induced either a complete or incomplete SCI in adult mice of either sex and divided those with incomplete injury into low or high functional recovery groups. Their sacrocaudal spinal cords were then extracted and used to study plasticity below injury, with tissue from naive animals as a control. Electrical stimulation of the dorsal roots elicited spasm-like activity in preparations of chronic severe SCI but not in the control. To evaluate overall synaptic inhibition activated by sensory stimulation, we measured the rate-dependent depression of spinal root reflexes. We found inhibitory inputs to be impaired in chronic injury models. When synaptic inhibition was blocked pharmacologically, all preparations became clearly spastic, even the control. However, preparations with chronic injuries generated longer spasms than control. We then measured excitatory postsynaptic currents (EPSCs) in motoneurons during sensory-evoked spasms. The data showed no difference in the amplitude of EPSCs or their conductance among animal groups. Nonetheless, we found that motoneuron persistent inward currents activated by the EPSCs were increased in chronic SCI. These findings suggest that changes in motoneuron excitability and synaptic inhibition, rather than excitation, contribute to spasms and are better suited for more effective therapeutic interventions.Significance Statement Neural plasticity following spinal cord injury is crucial for recovery of motor function. Unfortunately, this process is blemished by maladaptive changes that can cause muscle spasms. Pharmacological alleviation of spasms without compromising the recovery of motor function has proven to be challenging. Here, we investigated changes in fundamental spinal mechanisms that can cause spasms post-injury. Our data suggest that the current management strategy for spasms is misdirected toward suppressing excitatory inputs, a mechanism that we found unaltered after injury, which can lead to further motor weakness. Instead, this study shows that more promising approaches might involve restoring synaptic inhibition or modulating motoneuron excitability.

Transcutaneous spinal stimulation in patients with intrathecal baclofen pump delivery system: A preliminary safety study

Objective

To determine the effect of transcutaneous spinal stimulation (TSS) on an implanted intrathecal baclofen (ITB) pump in persons with traumatic spinal cord injury (SCI).

Design

Prospective clinical trial.

Participants

Five individuals with chronic traumatic SCI, >18 years of age, and an anteriorly implanted Medtronic SynchroMed™ II ITB pump delivery system.

Intervention

Transcutaneous spinal stimulation trials with cathode at T11/12, with pump interrogation before, during and after stimulation.

Results

There was no evidence of any effect of the TSS in regards to disruption of the ITB pump delivery mechanism. Communication interference with the interrogator to the pump occurred often during stimulation for log transmission most likely secondary to the electromagnetic interference from the stimulation. One individual had elevated blood pressure at the end of the trial, suspected to be unrelated to the spinal stimulation.

Conclusion

Based upon this pilot study, further TSS studies including persons with an implanted Medtronic SynchroMed™ II ITB pump can be considered when stimulating at the low thoracic spine, although communication with the programmer during the stimulation may be affected.

Frequency and Characteristics of Medical Complications in Rehabilitation Settings: A Scoping Review

OBJECTIVE

To synthesize the available evidence on medical complications occurring in adult patients in subacute inpatient rehabilitation, and to describe the impact on subacute length of stay and readmission to acute care.

DESIGN

Scoping review.

SUBJECTS

Adult patients, within the inpatient rehabilitation environment, who experienced medical complications, clinical deterioration and/or the requirement of transfer to acute care.

METHODS

A systematic search of MEDLINE and CINAHL electronic databases was undertaken to identify primary research studies published in English and French during the period 2000-2021. Study reporting followed the standards indicated by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews checklist (PRISMA-ScR).

RESULTS

A total of 47 studies were identified for inclusion. Key results included differences in the type and frequency of complications according to admission type, the proportion of patients experiencing at least 1 complication, and complications associated with transfer to acute care.

CONCLUSION

Patients admitted for inpatient rehabilitation are at high risk of medical complications and may not be medically stable during their admission, requiring care by clinicians with expertise in functional rehabilitation, and ongoing management by members of the multidisciplinary team with expertise in acute general medicine, infectious diseases and recognition and response to clinical deterioration.

Molecular Identification of Pro-Excitogenic Receptor and Channel Phenotypes of the Deafferented Lumbar Motoneurons in the Early Phase after SCT in Rats

Spasticity impacts the quality of life of patients suffering spinal cord injury and impedes the recovery of locomotion. At the cellular level, spasticity is considered to be primarily caused by the hyperexcitability of spinal α-motoneurons (MNs) within the spinal stretch reflex circuit. Here, we hypothesized that after a complete spinal cord transection in rats, fast adaptive molecular responses of lumbar MNs develop in return for the loss of inputs. We assumed that early loss of glutamatergic afferents changes the expression of glutamatergic AMPA and NMDA receptor subunits, which may be the forerunners of the developing spasticity of hindlimb muscles. To better understand its molecular underpinnings, concomitant expression of GABA and Glycinergic receptors and serotoninergic and noradrenergic receptors, which regulate the persistent inward currents crucial for sustained discharges in MNs, were examined together with voltage-gated ion channels and cation-chloride cotransporters. Using quantitative real-time PCR, we showed in the tracer-identified MNs innervating extensor and flexor muscles of the ankle joint multiple increases in transcripts coding for AMPAR and 5-HTR subunits, along with a profound decrease in GABAAR, GlyR subunits, and KCC2. Our study demonstrated that both MNs groups similarly adapt to a more excitable state, which may increase the occurrence of extensor and flexor muscle spasms.

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.

Decreasing pressure injuries and acute care length of stay in patients with acute traumatic spinal cord injury

OBJECTIVES

Identifying factors associated with the occurrence of pressure injuries (PI) during acute care and with longer length of stay (LOS), focusing on modifiable factors that can be addressed and optimized by the acute rehabilitation team.

DESIGN

Prospective cohort study.

SETTING

A single Level-1 trauma center specialized in SCI care.

PARTICIPANTS

A cohort of 301 patients with acute TSCI was studied.

OUTCOME MEASURES

The primary outcome was the occurrence of PI during acute care stay. The secondary outcome was acute care LOS. Bivariate and multivariate logistic or linear regression analyses were performed to determine the association between non-modifiable factors and outcomes (PI of any stage and acute LOS), whereas bivariate and hierarchical multivariate logistic or linear regression analyses were used for modifiable factors.

RESULTS

When controlling for the level and severity of the TSCI, the occurrence of pneumonia (OR = 2.1, CI = 1.1-4.1) was significantly associated with the occurrence of PI. When controlling for the level and severity of the TSCI, the occurrence of medical complications (PI, urinary tract infection and pneumonia) and lesser daily therapy resulted in significantly longer acute care LOS (P < .001).

CONCLUSIONS

Prevention of PI occurrence and the optimization of the acute care LOS represent crucial challenges of the acute rehabilitation team, as they are significantly associated with higher functional outcomes. Patients who develop pneumonia may benefit from more aggressive prevention strategies to reduce PI occurrence. Systematic protocols for the prevention of complications as well as greater volume of therapy interventions should be considered to optimize the acute care LOS.

Are early clinical manifestations of spasticity associated with long-term functional outcome following spinal cord injury? A retrospective study

STUDY DESIGN

Retrospective study of a prospective cohort of patients with traumatic spinal cord injury (SCI).

OBJECTIVES

Determine the relationship between the occurrence of early spasticity, defined as the development of signs and/or symptoms of spasticity during the hospitalization in traumatology, and the functional outcome 6-12 months following a SCI. Secondly, to determine the specific impact of early clonus, velocity-dependent hypertonia and/or muscle spasms on the functional outcome at the same timepoint.

SETTING

Single trauma center specialized in SCI care.

METHODS

One hundred sixty-two patients sustaining an acute traumatic SCI were included in the analyses. Comparative analysis was performed to describe the characteristics of patients with early spasticity. Correlations were performed to determine the relationship between the clinical signs of spasticity and the Spinal Cord Independence Measure (SCIM) scores collected 6-12 months after SCI.

RESULTS

51.9% of the cohort developed clinical signs of spasticity during the hospitalization in traumatology (29.7 days) following SCI. These showed a significantly lower total SCIM score and subscores compared to individuals without early spasticity at follow-up (p < 0.05). After adjusting for confounding factors, the occurrence of early spasms was only clinical sign of spasticity significantly associated with a decreased mobility at follow-up (r = -0.17, p = 0.04).

CONCLUSIONS

The development of signs and symptoms of spasticity, in particular the occurrence of spasms in the first month following the injury may be associated with decreased functional outcome and mobility. Early assessment of spasticity following SCI is thus recommended.

Reduction in post-spinal cord injury spasticity by combination of peripheral nerve grafting and acidic fibroblast growth factor infusion in monkeys

OBJECTIVE

Spasticity is a frequent complication after spinal cord injury (SCI), but the existing therapies provide only limited relief and are associated with adverse reactions. Therefore, we aimed to develop a novel strategy to ameliorate the spasticity induced by SCI.

METHODS

This nonrandomized controlled study used a repeated measurement design. The study involved four monkeys, two of which served as controls and only underwent spinal cord hemisection surgery at the T8 spine level. The other two monkeys underwent transplantation of sural nerve segments into the injured sites and long-term infusion of acidic fibroblast growth factor (aFGF). All monkeys received postoperative exercise training and therapy.

RESULTS

The combined therapy substantially reduced the spasticity in leg muscle tone, patella tendon reflex, and fanning of toes. Although all monkeys showed spontaneous recovery of function over time, the recovery in the controls reached a plateau and started to decline after 11 weeks.

CONCLUSIONS

The combination of peripheral nerve grafting and aFGF infusion may serve as a complementary approach to reduce the signs of spasticity in patients with SCI.