Functional outcome following Botulinum toxin A injection to reduce spastic equinus in adults with traumatic brain injury

Association of Lower Limb Focal Spasticity With Kinematic Variables During Walking in Traumatic Brain Injury

BACKGROUND AND PURPOSE

Focal muscle spasticity is defined as spasticity that affects a localized group of muscles. It is prevalent in many adult-onset neurological conditions, yet the relationship of focal muscle spasticity with walking remains unclear. Therefore, the aim of this study was to determine the relationship of focal muscle spasticity with the kinematics of walking in traumatic brain injury (TBI).

METHODS

Ninety-one participants with TBI underwent clinical gait analysis and assessment of focal lower limb muscle spasticity in a prospective cross-sectional study. A matched group of 25 healthy controls (HCs) were recruited to establish a reference dataset. Kinematic data for each person with and without focal muscle spasticity following TBI were compared with the HC cohort at a matched walking speed.

RESULTS

The TBI and HC cohorts were well matched. Only those with focal hamstring muscle spasticity walked significantly different to those without. They had significantly greater knee flexion (23.4° compared with 10.5°, P < 0.01) at initial contact. There were no other significant differences in kinematic variables between those with and without focal muscle spasticity. There was no significant association between focal muscle spasticity and walking speed.

DISCUSSION AND CONCLUSIONS

Focal muscle spasticity and abnormal kinematics whilst walking were common in this cohort of people with TBI. However, focal muscle spasticity had little relationship with kinematic variables, and no significant relationship with walking speed. This finding has implications for the treatment of focal muscle spasticity to improve walking following TBI. Focal muscle spasticity had little relationship with kinematic variables and walking speed in this cohort of people with TBI who could walk without assistance.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A381).

Altered Muscle Contributions are Required to Support the Stance Limb During Voluntary Toe-Walking

Toe-walking characterizes several neuromuscular conditions and is associated with a reduction in gait stability and efficiency, as well as in life quality. The optimal choice of treatment depends on a correct understanding of the underlying pathology and on the individual biomechanics of walking. The objective of this study was to describe gait deviations occurring in a cohort of healthy adult subjects when mimicking a unilateral toe-walking pattern compared to their normal heel-to-toe gait pattern. The focus was to characterize the functional adaptations of the major lower-limb muscles which are required in order to toe walk. Musculoskeletal modeling was used to estimate the required muscle contributions to the joint sagittal moments. The support moment, defined as the sum of the sagittal extensive moments at the ankle, knee, and hip joints, was used to evaluate the overall muscular effort necessary to maintain stance limb stability and prevent the collapse of the knee. Compared to a normal heel-to-toe gait pattern, toe-walking was characterized by significantly different lower-limb kinematics and kinetics. The altered kinetic demands at each joint translated into different necessary moment contributions from most muscles. In particular, an earlier and prolonged ankle plantarflexion contribution was required from the soleus and gastrocnemius during most of the stance phase. The hip extensors had to provide a higher extensive moment during loading response, while a significantly higher knee extension contribution from the vasti was necessary during mid-stance. Compensatory muscular activations are therefore functionally required at every joint level in order to toe walk. A higher support moment during toe-walking indicates an overall higher muscular effort necessary to maintain stance limb stability and prevent the collapse of the knee. Higher muscular demands during gait may lead to fatigue, pain, and reduced quality of life. Toe-walking is indeed associated with significantly larger muscle forces exerted by the quadriceps to the patella and prolonged force transmission through the Achilles tendon during stance phase. Optimal treatment options should therefore account for muscular demands and potential overloads associated with specific compensatory mechanisms.

The intravesical injection of highly purified botulinum toxin for the treatment of neurogenic detrusor overactivity

INTRODUCTION

We aimed to assess safety and efficacy of incobotulinumtoxinA for the treatment of neurogenic detrusor overactivity (NDO).

METHODS

We identified patients with NDO confirmed on urodynamics (UDS) and reported urgency incontinence (UI) in those who received intravesical incobotulinumtoxin A injection for neurogenic bladder between November 2013 and May 2017. Parameters studied were daytime frequency, daily incontinence episodes, daily pad use, clean intermittent catheterization (CIC) volumes, symptom scores (UDI6, IIQ7, PGII), and complications.

RESULTS

We examined 17 male patients who met inclusion criteria and underwent incobotulinumtoxinA injection. Mean age was 61.2±15.4 years. Fourteen patients (82%) were taking oral antimuscarinics prior to the incobotulinumtoxin A injection. There were improvements in the following parameters: average daily pads (4.5 to 3.3, p=0.465), daily urinary frequency (9.4 to 4.6, p=0.048), daily incontinent episodes (2.5 to 0.4, p=0.033), CIC volumes (400 to 550 mL, p=0.356), hours in between CIC (3.6 to 5.2, p=0.127), and the validated questionnaires UDI6 (30.6 to 7.4, p=0.543) and IIQ7 (52.4 to 6.8, p=0.029). There were no documented symptomatic urinary tract infections (UTIs) within 30 days of injection or reports of de novo urinary retention. Nine of 17 patients (53%) reported being dry at their first postoperative visit.

CONCLUSIONS

In this preliminary pilot study of a small cohort of males with NDO and UI, significant improvements were seen following incobotulinumtoxinA injection in daily frequency, incontinence episodes, hours in between CIC, and quality of life. Larger-scale and long-term studies are required to confirm these results, but initial findings are promising for wider use of this formulation.

Management of Spasticity After Traumatic Brain Injury in Children

Traumatic brain injury is a common cause of disability worldwide. In fact, trauma is the second most common cause of death and disability, still today. Traumatic brain injury affects nearly 475 000 children in the United States alone. Globally it is estimated that nearly 2 million people are affected by traumatic brain injuries every year. The mechanism of injury differs between countries in the developing world, where low velocity injuries and interpersonal violence dominates, and high-income countries where high velocity injuries are more common. Traumatic brain injury is not only associated with acute problems, but patients can suffer from longstanding consequences such as seizures, spasticity, cognitive and social issues, often long after the acute injury has resolved. Spasticity is common after traumatic brain injury in children and up to 38% of patients may develop spasticity in the first 12 months after cerebral injury from stroke or trauma. Management of spasticity in children after traumatic brain injury is often overlooked as there are more pressing issues to attend to in the early phase after injury. By the time the spasticity becomes a priority, often it is too late to make meaningful improvements without reverting to major corrective surgical techniques. There is also very little written on the topic of spasticity management after traumatic brain injury, especially in children. Most of the information we have is derived from stroke research. The focus of management strategies are largely medication use, physical therapy, and other physical rehabilitative strategies, with surgical management techniques used for long-term refractory cases only. With this manuscript, the authors aim to review our current understanding of the pathophysiology and management options, as well as prevention, of spasticity after traumatic brain injury in children.

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.

Early botulinum toxin treatment for spastic pes equinovarus--a randomized double-blind placebo-controlled study

BACKGROUND AND PURPOSE

Spastic pes equinovarus is a frequent pathological posture of the lower extremity. Botulinum toxin (BoNT/A) has been successfully applied to treat lower limb spasticity. However, the best time to initiate treatment remains unclear. A beneficial effect of an early treatment has been suggested in previous studies.

METHODS

A single-centre double-blind randomized placebo-controlled trial was performed to investigate the efficacy of BoNT/A to reduce muscle hypertonicity at the ankle. Fifty-two patients with unilateral or bilateral spastic pes equinovarus with a modified Ashworth score (mAS) of at least 1+ after stroke, traumatic brain injury or hypoxic encephalopathy were allocated to receive either BoNT/A or placebo treatment. A second, open injection was optional at week 12. Patients received unilateral or bilateral injections with 230 or 460 U onabotulinumtoxinA, respectively. The course of the mAS was explored during the open study phase.

RESULTS

Patients who had received BoNT/A treatment had lower mAS compared with placebo at week 12 (P < 0.01). During the open label phase, patients from the placebo group showed further deterioration of muscle tone despite starting from a similar baseline and receiving BoNT treatment. Spastic feet that had received BoNT/A in the first cycle had comparatively lower mAS scores over all follow-up data and at week 24 (P < 0.01).

CONCLUSIONS

The study demonstrates a reduction of muscular hypertonicity in spastic pes equines with BoNT/A treatment given during the first 3 months after the lesion. Exploratory analyses of the course of muscular hypertonicity during the open phase favour earlier to later treatment.

OnabotulinumtoxinA muscle injection patterns in adult spasticity: a systematic literature review

Background

OnabotulinumtoxinA has demonstrated significant benefit in adult focal spasticity. This study reviews the injection patterns (i.e., muscle distribution, dosing) of onabotulinumtoxinA for treatment of adult spasticity, as reported in published studies.

Methods

A systematic review of clinical trials and observational studies published between 1990 and 2011 reporting data on muscles injected with onabotulinumtoxinA in adult patients treated for any cause of spasticity.

Results

28 randomized, 5 nonrandomized, and 37 single-arm studies evaluating 2,163 adult patients were included. The most frequently injected upper-limb muscles were flexor carpi radialis (64.0% of patients), flexor carpi ulnaris (59.1%), flexor digitorum superficialis (57.2%), flexor digitorum profundus (52.5%), and biceps brachii (38.8%). The most frequently injected lower-limb muscles were the gastrocnemius (66.1% of patients), soleus (54.7%), and tibialis posterior (50.5%). The overall dose range reported was 5–200 U for upper-limb muscles and 10–400 U for lower-limb muscles.

Conclusions

The reviewed evidence indicates that the muscles most frequently injected with onabotulinumtoxinA in adults with spasticity were the wrist, elbow, and finger flexors and the ankle plantar flexors. OnabotulinumtoxinA was injected over a broad range of doses per muscle among the studies included in this review, but individual practitioners should be mindful of local regulatory approvals and regulations.

The effect of isolated gastrocnemius contracture and gastrocnemius recession on lower extremity kinematics and kinetics during stance

BACKGROUND

Isolated gastrocnemius contracture limits ankle dorsiflexion with full knee extension and is potentially problematic during mid-stance of gait when 10° of dorsiflexion and full knee extension are needed. It is during this time that patients with isolated gastrocnemius contracture may demonstrate altered kinematics and/or kinetics. When conservative management fails to resolve painful foot pathologies associated with non-spastic isolated gastrocnemius contracture, gastrocnemius recession surgery has been suggested to resolve contracture and improve function and strength. However, there are no published reports on lower extremity kinematics/kinetics in the non-spastic isolated gastrocnemius contracture population. Assessment of alterations in gait mechanics is necessary to examine the effects of this potential surgical intervention.

METHODS

Lower extremity kinematics and kinetics were assessed in 6 patients clinically diagnosed with isolated gastrocnemius contracture pre- and post-surgical recession compared with 33 healthy control participants.

FINDINGS

Pre-operatively, patients with isolated gastrocnemius contracture demonstrated significantly increased peak knee flexion angles and knee flexion moments during mid-stance. There were no differences in peak ankle dorsiflexion angle or peak plantar flexion moment. Gastrocnemius recession did not alter gait kinematics/kinetics following surgery. Joint kinematic strategies utilized to compensate for isolated gastrocnemius contracture varied minimally between participants with IGC; most employed a flexed knee strategy, while one participant utilized a reduced ankle dorsiflexion strategy.

INTERPRETATION

Select post-surgical gait mechanics were unaltered; however, gait mechanics were not similar between non-spastic isolated gastrocnemius contracture patients and healthy control participants. Surgical intervention for patients with isolated gastrocnemius contracture does not appear to create any negative gait adaptations; however, patients may benefit from gait retraining post-recession as maladaptive gait patterns persist post operatively.

BTX-A Administration to the Target Muscle Affects Forces of All Muscles Within an Intact Compartment and Epimuscular Myofascial Force Transmission

Measurement of forces of mono- and bi-articular muscles of an entire intact muscle compartment can allow for a comprehensive assessment of the effects of Botulinum toxin type A (BTX-A) both at and beyond the injection site, and in conditions close to those in vivo. The goal was to test the hypotheses that BTX-A affects (1) the forces of not only the injected but also the noninjected muscles of the compartment, and (2) epimuscular myofascial force transmission (EMFT). Two groups of Wistar rats were tested: Control (no BTX-A injected) and BTX (0.1 units of BTX-A were injected exclusively to the mid-belly of TA). Isometric forces were measured simultaneously at the distal tendons of the tibialis anterior (TA) at different lengths, the restrained extensor digitorum longus (EDL) and the extensor hallucis longus (EHL) muscles and at the proximal tendon of EDL. Five days post-injection, BTX-A did affect the total forces of all muscles significantly: (1) The TA force decreased differentially (by 46.6%–55.9%) for most lengths such that a significant negative correlation was found between force reductions and increased muscle length. The maximum TA force decreased by 47.3%. However, the muscle’s length range of force production did not change significantly. (2) Distal and proximal EDL forces decreased (on average by 67.8% and 62.9%, respectively). (3) The EHL force also decreased (on average by 9.2%). The passive forces of only the TA showed a significant increase at higher lengths. EMFT effects were shown for the control group: (1) at the shortest TA lengths, the EDL proximo-distal force differences were in favor of the distal force, which was reversed at higher lengths. (2) the EHL force measured at the shortest TA length decreased (by 34%) as a function of TA lengthening. After BTX-A exposure, such EMFT effects disappeared for the EDL, whereas they remained as profound for the EHL. Exposure to BTX-A does affect forces of all muscles operating in an intact compartment. For the BTX-A injected muscle, the reduction in muscle force becomes less pronounced at higher muscle lengths. BTX-A also has effects on EMFT, however, these effects are not uniform within the anterior crural compartment. Decreased forces of the noninjected synergistic muscles suggest the presence of unintended additional effects of BTX-A both for the targeted distal joint and for the nontargeted proximal joint.

Are gait and mobility measures responsive to change following botulinum toxin injections in adults with lower limb spasticity?

PURPOSE

To determine whether gait and mobility measures are responsive to change following botulinum toxin (BoNT) injections in adults with lower limb spasticity.

METHOD

Independently ambulant adults who attended a spasticity clinic for lower limb BoNT injections were eligible to participate. The 10 m walk test (shoes on and off), timed up and go test and 6-min walk test were performed before injection and 1 month later. Participants completed a global rating of change scale (GRCS) at follow up. Comparisons were made between participants' ratings of change and change in walking performance. Effect sizes (ES) and standard error of measurement (SEM) were calculated for each outcome.

RESULTS

Thirty-nine patients (22 female, 17 male; mean age 51 ± 12 years; range 26-74 years) with a median spasticity duration of 53 months participated. Statistically significant changes were found in all gait and mobility measures at 1 month following injection. All ES were small (<0.2) and SEM for each measure was large. The global rating of change scale (GRCS) indicated that 66% of participants perceived that their walking had improved. However, there was a significant relationship between GRCS and performance on walking tests for the 10 m walk test with shoes off (p = 0.01) and timed up and go test (p = 0.02) only.

CONCLUSION

Commonly used walking tests may not be responsive to change following BoNT injection. The small ES suggest that BoNT has a modest effect on walking ability. Tests of walking performance may not be sufficient to capture all clinically relevant changes in walking ability following BoNT injection of the lower limb.

Botulinum toxin effects on gasatrocnemius strength and plantar pressure in diabetics with peripheral neuropathy and forefoot ulceration

BACKGROUND

High forefoot plantar pressure is associated with plantar ulcers in people with diabetes and peripheral neuropathy. The purpose of this pilot study was to determine the safety and efficacy of botulinum toxin A injected into the gastrocnemius-soleus muscles to reduce muscle strength and plantar pressure.

METHODS

This double blind, randomized clinical trial studied 17 people with diabetes mellitus, peripheral neuropathy and a forefoot plantar ulcer. Subjects were randomized into one of three groups receiving gastrocnemius-soleus muscle injections on the involved side with; 1) Saline (n = 5, weight =99± 21 kg), 2) 200-units of Botox® (n = 7, weight = 101± 5 kg), or 3) 300-units of Botox® (n = 5, weight = 129± 22 kg). Botox® dose was converted to units/kg, the majority received between 1.9 and 2.4 units/kg (n = 11) and one 3.2 units/kg. Plantarflexor peak torque and forefoot peak plantar pressure were quantified prior and 2 weeks post-injection.

RESULTS

There were no complications from the injections. Plantarflexor peak torque on the involved side increased in the placebo and 300 groups (3± 4 Nm and 6± 10 Nm, respectively) and decreased -8± 11 Nm in the 200 group. There was no relationship between units/kg of Botox® for each subject and change in plantarflexor peak torque. Forefoot peak plantar pressure did not change in the placebo and 300 groups (0± 11 and 0± 5 N/cm(2), respectively) and decreased -4± 16 N/cm2 (4%) for the 200 group.

CONCLUSION

There were no adverse events associated with the Botox® injections. This study was unable to determine the dose to consistently reduce plantarflexor strength and forefoot plantar pressure. Additional research is needed to investigate diabetes mellitus specific physiological changes and their impact of BoNT-A effectiveness in order to guide appropriate dosing.

Walking assessment with instrumented insoles in patients with lower limb spasticity after botulinum toxin infiltration

INTRODUCTION

Botulinum toxin A (BTA) improves the kinematic parameters of gait in patients with spasticity of lower limbs, but there are no studies in which kinetic parameters are measured with instrumented insoles. We therefore used instrumented insoles to perform a functional assessment of therapeutic results in patients with lower limb spasticity after brain injury or spinal cord infiltration indicating BTA.

MATERIAL AND METHODS

Ten patients (11 lower limbs) seen in a Neurorehabilitation Unit. The tests carried out included clinical examination, gait assessment (Functional Ambulation Categories (FAC); Hospital de Sagunto Gait Scale), and biomechanical assessment (Biofoot / IBV version 5.0), before and three weeks after infiltration with BTA.

STATISTICS

t-test for related samples of clinical variables, functional variables and biomechanical variables before and after infiltration. Level of significance P< .05. Qualitative method to assess whether changes in the biomechanical variables tended toward normal values.

RESULTS

BTA improves muscle tone, joint arch and frequency of spasms (P<.01). The patient sample showed a high level of satisfaction with the improvement in symptoms. There were no changes in walking ability after injection. There were no statistically significant changes in biomechanical parameters, but there was improved gait cadence. The relatively small statistical significance close to P=.1 of the peak pressure in the heel after injection indicates the need for further studies with instrumented insoles in people with spasticity due to central nervous system injury.

CONCLUSIONS

With the decrease in muscle tone after infiltration with BTA the clinical symptoms associated with muscle tone improved without any functional changes in gait scales. The changes in the biomechanical parameters show that larger studies using instrumented insoles should be performed in the population with spasticity after a central nervous system injury treated with BTA infiltration.

Therapeutic use of botulinum toxin in neurorehabilitation

The botulinum toxins (BTX), type A and type B by blocking vesicle acetylcholine release at neuro-muscular and neuro-secretory junctions can result efficacious therapeutic agents for the treatment of numerous disorders in patients requiring neuro-rehabilitative intervention. Its use for the reduction of focal spasticity following stroke, brain injury, and cerebral palsy is provided. Although the reduction of spasticity is widely demonstrated with BTX type A injection, its impact on the improvement of dexterity and functional outcome remains controversial. The use of BTX for the rehabilitation of children with obstetrical brachial plexus palsy and in treating sialorrhea which can complicate the course of some severe neurological diseases such as amyotrophic lateral sclerosis and Parkinson's disease is also addressed. Adverse events and neutralizing antibodies formation after repeated BTX injections can occur. Since impaired neurological persons can have complex disabling feature, BTX treatment should be viewed as adjunct measure to other rehabilitative strategies that are based on the individual's residual ability and competence and targeted to achieve the best functional recovery. BTX therapy has high cost and transient effect, but its benefits outweigh these disadvantages. Future studies must clarify if this agent alone or adjunctive to other rehabilitative procedures works best on functional outcome.

Motor impairment rehabilitation post acquired brain injury

OBJECTIVE

We sought to investigate the efficacy of treatment strategies used to manage motor impairments following acquired brain injury (ABI) in order to provide guidance for clinical practice based on the best available evidence.

METHODS AND MAIN OUTCOMES

A systematic review of the literature from 1980-2005 was conducted focusing on pharmacological, non-pharmacological, and exercise interventions available for motor impairments post ABI. The efficacy of a given intervention was classified as strong (supported by two or more randomized controlled trials (RCTs)), moderate (supported by a single RCT), or limited (supported by other types of studies in the absence of RCTs).

RESULTS

Thirty-six studies examining a variety of treatment approaches for motor impairments and activity limitations following ABI were evaluated. The majority of interventions are only supported by limited evidence. However, there is strong evidence that serial casting does reduce ankle plantar contractures due to spasticity of cerebral origin, and strong evidence also suggests that partial body weight supported gait training does not provide any added benefit over conventional gait training. There is also moderate evidence to support the use of functional fine motor control retraining to improve motor coordination, tizanidine for upper and lower extremity spasticity, and specific sit-to-stand training to improve functional ability. There is also moderate evidence that casting alone is as effective as casting and Botulinum toxin injections for plantar contractures.

CONCLUSIONS

Although there are a variety of treatment strategies to manage motor impairments and activity limitations following ABI, most are only supported by limited evidence pointing to the need for studies of improved methodological quality in this area.

Observational gait analysis in traumatic brain injury: accuracy of clinical judgment

OBJECTIVE

To determine the accuracy of clinicians' visual observations of gait disorders following traumatic brain injury (TBI).

METHODS

30 ambulant participants (sample of convenience) receiving physiotherapy for mobility limitations following TBI and 25 age, height, weight and sex matched healthy unimpaired controls (HC) were recruited. Kinematic and ground reaction force data during gait were captured and video recordings were concurrently collected. Participants with TBI walked at self-selected speed whilst HCs walked at preferred speed as well as the mean TBI speed for comparison. 40 doctors, experienced physiotherapists, new graduate physiotherapists and novices were observers. Each viewed and rated 36 gait variables for a randomized sub-sample of 10 participants with TBI. Observer inaccuracy was calculated for each gait variable.

RESULTS

Overall the accuracy of observational gait analysis was low and there was considerable variability in observations between clinicians. For most kinematic variables, observer inaccuracy ranged from 30% to 50%. Although experienced observers were generally more accurate, average inter-item correlations were low, indicating that experience did not consistently improve the accuracy of visual observations. Observational plane, gait variable type, the joint or the segment had little effect on accuracy of observations.

CONCLUSIONS

Observational gait analysis for adults with TBI has relatively low accuracy. Some of the gait abnormalities evident from quantitative gait analysis were not detected by observational gait analysis.

The effects of botulinum toxin A on muscle histology during distraction osteogenesis

Distraction osteogenesis is a highly successful method of bone formation, yet muscle fibrosis and contractures can result in significant morbidity. In the current study, we investigate the efficacy of botulinum toxin A in preventing fibrosis and potentially increasing muscle development in distracted muscles. Fifteen New Zealand White rabbits underwent tibial distraction at 1.5 mm/day until a 20% gain was achieved. Treatment groups were divided by drug (saline or botulinum toxin) and target muscle (gastrocnemius or tibialis anterior). Two additional control animals received no treatment. Bromeodeoxyuridine was delivered continuously throughout the 8-week experiment, and following muscle harvest. Tissues were stained for BrdU, Pax-7, vimentin, and haematoxylin and eosin staining. Mitotic activity increased in all distracted animals; however, in the animals receiving botulinum toxin A injections into the gastrocnemius, the antagonist tibialis anterior suffered up to 9% less fibrosis than distraction alone (p = 0.024). Use of botulinum A toxin did not appear to promote or improve neogenesis of muscle fibers, nor did it decrease fibrosis in the injected muscles. It appears from this study, and a previously published study on the effects of this toxin on muscle function, that botulinum A toxin maybe of some benefit in decreasing morbidity in the antagonist muscle but not the muscle injected with the toxin.

Effects of botulinum toxin A on functional outcome during distraction osteogenesis

Distraction osteogenesis is useful for correcting limb length inequality, deformities, or short stature. Despite success with bone formation, soft tissue maladaptations including muscle and joint contracture may lead to undesirable results. Botulinum toxin A has been useful in treating spasticity in cerebral palsy, and has been used clinically in select cases to allay contracture in distraction osteogenesis. This study examines the toxin's efficacy in preventing distraction-induced loss of muscle strength and range of motion. The left tibias of 15 New Zealand White rabbits were distracted 1.5 mm/day until approximately a 20% gain was achieved. Each treatment group was divided into animals injected with saline or botulinum toxin in either the gastrocnemius or tibialis anterior muscles. A control group of two additional animals underwent no surgical procedure. Strength and range of motion were assessed prior to, and following, the experiment. At the study's end, animals were euthanized and muscles were harvested, when lengths and weights were recorded. All muscles injected with botulinum toxin showed decreased wet weight and persistent weakness upon completion of the study. Range of motion decreased in all distracted animals. When the gastrocnemius was injected, its strength was reduced but the tibialis anterior strength was preserved, and the limb achieved 22% greater dorsiflexion than saline controls (p = 0.016). When the tibialis anterior received the toxin, plantarflexion was increased by 23% (p = 0.049). Botulinum toxin injection prior to limb distraction increases the "post-lengthened" excursion of the injected muscle and this increased length may have a protective effect on its antagonist. In toxin-injected gastrocnemius muscles, the level of equinus contracture is reduced due to length gains in the Achilles tendon while the anterior tibialis maintains its ability to generate torque. Injection of botulinum toxin in the gastrocnemius may minimize equinus contracture and protect the anterior tibialis from damage during human tibial lengthening. Longer follow-up studies are needed to ensure that toxin-induced muscle weakness resolves with time.

Effects of Botulinum Toxin-A on Gait Velocity, Step Length, and Base of Support of Patients with Dynamic Equinovarus Foot

OBJECTIVE

The aim of this study was to identify if botulinum toxin type A is a drug able to modify walking velocity, step length, and width of the base of support of adult patients with dynamic equinovarus foot deformity resulting from upper motor neuron syndrome.

DESIGN

This retrospective study analyzed data from 20 patients' files selected from 448 consecutive charts. The main inclusion criteria were the presence of dynamic equinovarus foot deformity due to upper motor neuron syndrome, age between 20 and 80 yrs, evaluation of temporospatial parameters of gait by the Gait Mat II before and 4 wks after botulinum toxin type A injection to the calf muscles, and the ability to walk barefoot, unassisted, and without braces. For data analysis, based on walking velocity, we divided the patients into two groups, slow walking velocity (0.18-0.49 m/sec) and medium walking velocity (0.50-0.99 m/sec).

RESULTS

Width of the base of support was significantly reduced after botulinum toxin type A treatment, both for the affected (P < 0.005) and the unaffected limbs (P < 0.002), in the group of subjects walking at medium velocity. Walking velocity or step length of either group of patients was not significantly modified by botulinum toxin type A treatment.

CONCLUSIONS

Based on this study, a significant effect of botulinum toxin type A on width of the base of support is evident and seems to be the result of a better position of the affected foot during the stance phase of locomotion leading to increased body stability and consequent reduction of width of the base of support of the unaffected limb. No change was evident in step length or walking velocity for this patient population.

Traumatic brain injury in the elderly: diagnostic and treatment challenges

The purpose of this review is to introduce geriatric practitioners to issues and challenges presented in the elderly after onset of traumatic brain injury (TBI). Issues discussed include the magnitude of TBI in the elderly, mechanisms of onset, issues specific to both acute and rehabilitation care for the elderly with TBI, and specific physical and behavioral manifestations of TBI that may need to be addressed on an inpatient or outpatient basis. General guidelines are provided for the diagnosis and treatment of older individuals who have TBI, with specific clinical scenarios illustrating key points.

Management of spasticity in adults: practical application of botulinum toxin

Spasticity, characterized by increased muscle tone, exaggerated stretch reflexes, and abnormal limb posture, is a common sequel of central nervous system pathology. Historically, medicinal treatments have been of limited efficacy. This review discusses the clinical features of spasticity, the functional and pathological consequences, and treatment. It reviews the most common patterns of spasticity encountered in the upper and lower limbs and focuses on focal treatment of spastic muscles with the three commercially available botulinum toxins Botox, Dysport, and Myobloc/NeuroBloc. It addresses practical details such as muscle selection and identification, drug dilution, and doses.

A comparison of gastrocnemius muscle-tendon unit length during gait using anatomic, cadaveric and MRI models

Computing the length of a specific muscle is often of interest both in the study of human movement and the optimization of surgical techniques. The objective of this study was to compare three widely used methods of calculating gastrocnemius muscle-tendon unit (MTU) length. Gastrocnemius MTU length was calculated from the sagittal knee and ankle kinematics of 20 normal adults using three different methods: one based on cadaveric dissection and joint manipulation, one based on anatomic computer software modeling with insertion points obtained from cadavers and the third based on MRI measurements. All methods were normalized to percent anatomic neutral length (%ANL) with 100% at full knee extension and neutral ankle plantar-dorsiflexion. At the longest length (terminal stance), mean values (% ANL+/-standard deviation) were found to be 99.3+/-0.8, 101.8+/-0.5 and 102.4+/-0.7 for the MRI, cadaveric and anatomic methods, respectively. During the shortest length (early swing), the MRI, cadaveric and anatomic methods had mean values of 93.0+/-0.6, 92.2+/-2.0 and 91.9+/-2.1% ANL, respectively. All methods showed statistically significant differences (p<0.01) from each other in terminal stance and early swing, while loading and terminal swing lengths were similar among all methods. The gastrocnemius MTU calculated using the MRI-based method was found to be the shortest. Additional research is needed in order to validate a model for calculating gastrocnemius MTU length using in vivo methods of estimating the gastrocnemius moment arm at the knee and ankle.

From frown lines to fissures: Therapeutic uses for botulinum toxin

INTRODUCTION

Since the pharmacological mode of action of botulinum toxin (BTX) has been elucidated, its therapeutic potential has been increasingly recognised. The aims of this review were to summarize our current understanding of the pharmacological action of this agent and to review its therapeutic uses.

METHODS

An electronic literature search with Medline (January 1965 to December 2004) was carried out to identify articles related to the pharmacological mode of action and clinical uses for botulinum toxin using the keyword "botulinum toxin".

RESULTS AND CONCLUSION

Botulinum toxin A is emerging as a valuable clinical tool, both for diagnostic and therapeutic purposes in a wide variety of disorders, and is already the treatment of choice for selected conditions. Better understanding of its modes of action may identify alternative targets for pharmacological intervention, and may allow development of longer acting drugs with lower immunogenicity. Therapeutic uses of BTX-A must be assessed systematically in prospective studies, and the clinical role of other subtypes requires evaluation.