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At least 415 records · Page 23Linked to original sources
PubMed1995

Progressive kyphosis and neurologic compromise complicating spondylothoracic dysplasia in infancy (Jarcho-Levin syndrome).

STUDY DESIGN: This is a case report and review of the literature. OBJECTIVE: To review the orthopedic literature regarding the spinal abnormalities found with spondylothoracic dysplasia, and to present the history and management of severe kyphosis with neurologic impairment in an infant with spondylothoracic dysplasia. SUMMARY OF BACKGROUND DATA: Spondylothoracic dysplasia (Jarcho-Levin syndrome) is a rare form of short-limbed dwarfism characterized by extensive vertebral and chest-wall abnormalities. Although the spinal anomalies generally are radiographically severe, no patient previously reported in the English orthopedic literature has required surgical stabilization. METHODS: The clinical findings, course, and surgical management of an infant with spondylothoracic dysplasia and severe congenital kyphosis are presented. This patient required anterior decompression and anterior/posterior spinal fusion to obtain stabilization. The follow-up from the index surgical procedure was 2 years. RESULTS: The patient underwent an initial anteroposterior fusion and decompression at 5 months of age. She underwent revision of both anteroposterior procedures 7 months later because of pseudarthroses and a progressive kyphosis. Her residual neurologic abnormality was minimal and she appeared to have a stable fusion at 24 months post-index procedure. CONCLUSIONS: The spinal abnormalities associated with spondylothoracic dysplasia may not be as benign as previously reported. Sagittal, as well as frontal, plane deformities may exist secondary to multiple hemivertebrae. Longer life span, possibly due to improved pulmonary care, may increase the incidence of deformities requiring intervention.

Dwarfism↗
PubMed2000

The relationship between tight hamstrings and lumbar hypolordosis in children with cerebral palsy.

STUDY DESIGN: Retrospective clinical and radiographic review. OBJECTIVE: To assess the influence of tight hamstrings on the sagittal alignment of the thoracic and lumbar spine in children with cerebral palsy. SUMMARY OF BACKGROUND DATA: It is postulated that tight hamstrings may produce a hypolordosis of the lumbar spine. The abnormal sagittal contour of the spine may lead to increased stresses in the lumbar spine and subsequent pain and disability. This is of special concern in children with cerebral palsy who often have shortened spastic hamstring muscles. METHODS: Twenty-one patients were evaluated, with a mean age of 9.4 years. Standing and sitting lateral spine films were obtained and the lumbar lordosis and thoracic kyphosis were measured using the Cobb method. The popliteal angle was measured to assess hamstring tightness, such that a large popliteal angle indicates tight hamstrings. RESULTS: We found a statistically significant correlation between the sitting lumbar curve and popliteal angle (Pearson correlation value -0.77, P < 0.01). As the popliteal angle increased, the amount of lumbar lordosis decreased. This correlation was less significant when the patient was standing (Pearson correlation value -0.59). CONCLUSION: This study demonstrates that there is a correlation between tight hamstrings, as measured by the popliteal angle, and decreasing lumbar lordosis, especially when sitting.

Adolescent↗
PubMed2002

Spasm of accommodation associated with closed head trauma.

Spasm of accommodation, creating pseudomyopia, is generally associated with miosis and excess convergence as part of spasm of the near reflex. It may also exist as an isolated entity, usually attributed to psychogenic causes. We present six cases of accommodative spasm associated with closed head injury. All patients were male, ranging in age between 16 and 37 years. The degree of pseudomyopia, defined as the difference between manifest and cycloplegic refraction, was 1.5 to 2 diopters. A 3-year trial of pharmacologically induced cycloplegia in one patient did not lead to reversal of the spasm when the cycloplegia was stopped. All patients required the manifest refraction to see clearly at distance. The pseudomyopia endured for at least 7 years following head trauma. This phenomenon may represent traumatic activation or disinhibition of putative brain stem accommodation centers in young individuals.

Accommodation, Ocular↗
PubMed2006

Botulinum toxin injection site localization for the tibialis posterior muscle.

Thirty-one cadaveric lower limbs were dissected to identify the innervation of the tibialis posterior muscle to aid localization of the injection site for botulinum toxin for the treatment of an equinovarus deformity. A posterior midline surface-anatomy axis was defined from the level of the head of the fibula proximally to the intermalleolar axis distally. The nerve to tibialis posterior branched from the tibial trunk 13.4% down this axis and entered the muscle 22.1% along the same axis, within 1 cm of the midline. We also report the use of ultrasound for muscle localization at the level of the anatomically defined motor point.

Botulinum Toxins↗
PubMed2006

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.

Adult↗
PubMedDate not supplied

Upper extremity tendon transfers in cerebral palsy: electromyographic and functional analysis.

This study was undertaken to evaluate tendon transfers in a group of children with spastic hemiplegia. Muscle grading, video recordings of function, and electromyographs were performed on 12 patients preoperatively. Postoperative electromyograms were obtained on 16 transferred tendons in eight patients as the children performed assigned tasks. Clinical evaluation demonstrated improvement in all patients at follow-up, which averaged 20 months. Four of the 16 muscles showed changes in their electrical activity postoperatively. Three muscles that fired continuously became phasic, and one muscle changed phase to match its recipient. Pre- and postoperative electromyography with video analysis provided a more complete understanding of the characteristics of tendon function with tendon transfers in cerebral palsy.

Adolescent↗
PubMedDate not supplied

Insufficiency of the hip adductor after anterior obturator neurectomy in 42 children with cerebral palsy.

Forty-two children with cerebral palsy treated between 1970 and 1982 for correction of adduction and internal rotation of the hip were studied. According to the combined procedures and the effects of surgical manipulations, two groups were evaluated. The results of release of the adductor longus and gracilis without anterior obturator neurectomy were satisfactory when combined with proximal release of medial hamstrings. Hypertonicity in hip adduction was relieved. In cases of loss of function of the adductor brevis with anterior obturator neurectomy, the results were not satisfactory, and hyperabduction of the hip was inadequate. The adductor brevis plays an important role in stability of the hip.

Adolescent↗
PubMed2004

Evidence for force-feedback inhibition in chronic stroke.

The presence of force-feedback inhibition was explored during reflex responses in five subjects with known incidence of stroke. Using constant velocity stretches, it was previously found that after movement onset, active reflex force progressively increases with increasing joint angle, at a rate proportional to a fractional exponent of the speed of stretch. However, after the reflex force magnitude exceeds a particular level, it begins rolling off until maintaining a steady-state value. The magnitudes of these force plateaus are correlated with the speed of stretch, such that higher movement speeds result in higher steady-state forces. Based upon these previous studies, we hypothesized that force plateau behavior could be explained by a force-feedback inhibitory pathway. To help facilitate an understanding of this stretch reflex force roll off, a simple model representing the elbow reflex pathways was developed. This model contained two separate feedback pathways, one representing the monosynaptic stretch reflex originating from muscle spindle excitation, and another representing force-feedback inhibition arising from force sensitive receptors. It was found that force-feedback inhibition altered the stretch reflex response, resulting in a force response that followed a sigmoidal shape similar to that observed experimentally. Furthermore, simulated reflex responses were highly dependent on force-feedback gain, where predicted reflex force began plateauing at decreasing levels with increases in this force-feedback gain. The parameters from the model fits indicate that the force threshold for force-sensitive receptors is relatively high, suggesting that the inhibition may arise from muscle free nerve endings rather than Golgi tendon organs. The experimental results coupled with the simulations of elbow reflex responses suggest the possibility that after stroke, the effectiveness of force-feedback inhibition may increase to a level that has functional significance. Practical implications of these findings are discussed in relation to muscle weakness commonly associated with stroke.

Chronic Disease↗
PubMed1990

Control of isometric muscle activity in cerebral palsy.

Voluntary control of muscle contraction was examined in five adults with cerebral palsy, who were required to track a moving target by continuously varying the level of isometric contraction of elbow flexor muscles (measured by EMG). First performance varied from minimal control to almost normal control, depending on the severity of disability. Practice over 12 weeks reduced inappropriate muscle activity in the most disabled patients, but there was no increase in appropriate muscle activity for any patient beyond that observed after the first few minutes of tracking. Thus their ability to translate a visual response into the appropriate motor activity was impaired, and there was no evidence of potential to overcome this. This supports the authors' earlier proposal that impairment of sensory-motor learning is the primary cause of functional disability in cerebral palsy. The EMG tracking task may provide a technique for assessing the ability of individuals with cerebral palsy to control muscle contraction.

Adult↗
PubMed1991

Improvement of functional sitting position for children with cerebral palsy.

Twenty-three children with cerebral palsy were photographed and video-filmed in six different sitting positions--including a hypothetical functional position--and the video-films and photographs were analysed. It was found that pathological movements were minimised and postural control and arm and hand function best when the child was sitting in a forward-tipped seat, with a firm backrest supporting the pelvis, arms supported against a table and feet permitted to move backward.

Activities of Daily Living↗
PubMed1991

Modifications to the traditional description of neurosegmental innervation in myelomeningocele.

The consistency between patterns of lower-limb muscle strengths in children with myelomeningocele and Sharrard's classic description of segmental innervation was examined in 291 patients. Although it has been assumed that medial hamstring innervation was from a similar neurosegmental level as gluteus medius, and gluteus maximus was from a similar level as gastrocnemius-soleus, the authors found that medial hamstring strength more frequently correlated with iliopsoas and quadriceps, and glutei with anterior tibialis. It is proposed that children with myelomeningocele be grouped according to specific muscle strength rather than by neurosegmental level.

Adolescent↗
PubMed1993

Influence of different sitting positions and abduction orthoses on leg muscle activity in children with cerebral palsy.

A surface electromyogram (EMG) was recorded from four leg muscles to measure the effects of various seat inclinations and an abduction orthosis on eight children with cerebral palsy and controls during performance of an upper-extremity task and while listening to a story. EMG responses were lowest in the forward-leaning and horizontal positions with the abduction orthosis, and highest in reclined and horizontal positions without the orthosis for both groups of children during the performance of an upper-extremity task. While listening to a story, there was no median EMG activity in any muscles of the controls, but there were wide variations in those of the children with cerebral palsy. The results indicate that the use of an abduction orthosis and horizontal and forward-leaning seats decrease lower-extremity muscle activity, and so it is possible that it might also improve upper-extremity function.

Adolescent↗
PubMed2004

The Leg Drop Pendulum Test performed under general anesthesia in spastic cerebral palsy.

The general aim of this study was to examine the stiffness and damping characteristics (rate at which oscillations diminish) of limbs of a small population of patients with spastic cerebral palsy (CP) during the Leg Drop Pendulum Test while under general anesthesia and to compare them with patients without CP, both awake and under similar anesthetized conditions. To facilitate a quantitative comparison the authors defined a set of parameters that reflect the stiffness and damping of limbs with spasticity under general anesthesia. To give these parameters more meaning a similar set was constructed for children without disabilities under conditions of normal wakefulness and under anesthesia. The test population of 10 patients with spasticity ranged in age from 4 to 19 years and had a mean age of 10 years 9 months (SD 5 years 10 months); there were four females and six males. The control population consisted of eight patients without disabilities who ranged in age from 7 to 19 years with mean age of 13 years 9 months (SD 3 years 3 months); there were six females and two males. To even out the populations, two limbs from the non-affected sides of two patients with hemiplegic spasticity (both female) were used in the control group. The Leg Drop Pendulum Test was administered to 10 limbs with spastic CP and 10 control limbs under general anesthesia. The two test populations were chosen from patients who were previously scheduled to undergo surgery. Two measures compared limbs of those under anesthetic with those under alert conditions: the damped natural frequency and the damping ratio. The natural frequency is the frequency at which a pendulum oscillates as it comes to rest; the damping ratio is a measure of how quickly the oscillations diminish. In spasticity, active muscle tone disappeared under anesthesia. In both groups the underlying biomechanics of the limb varied considerably. In controls the variation seemed to be growth related.

Adolescent↗
PubMed1981

The action of dantrolene sodium on rat fast and slow muscle in vivo.

1. Rats, anaesthetized with urethane, were injected intravenously with dantrolene sodium in a carrier solution of 5% mannitol taken to pH 10 with NaOH. This carrier solution itself was without effect on extrafusal muscle contraction. 2. Dantrolene sodium (5 mg/kg) had a greater depressant action on the twitch contraction of the fast extensor digitorum longus (EDL) muscle than on the slow soleus (SOL) muscle. The EDL twitch was depressed to 25.9% +/- 1.2% (mean + s.e. mean, n = 7) of control whereas the SOL twitch was depressed to 31.3% +/- 0.4% (n = 9). These values were significantly different at the P less than 0.001 level. 3. The twitch contraction time to peak was reduced by approximately 35% in both EDL and SOL by dantrolene sodium. However, the drug reduced the half relaxation time of SOL by approximately 30% but that of EDL was hardly affected. 4. The effect of dantrolene sodium on contractions elicited by repetitive stimulation was dependent upon the stimulation frequency. For the SOL muscle the greater depression was produced at a stimulation frequency of 25 Hz and for EDL at 75 Hz. The minimum of depression was produced for a full fused tetanus for both muscles. 5. The significance of these findings is discussed in terms of the action of dantrolene sodium on motor control in the intact animal.

Animals↗
PubMed1994

The effects of phorbol 12,13-diacetate on responses of guinea-pig isolated trachea to methylxanthines, isoprenaline and ryanodine.

1. Using guinea-pig isolated trachea, we have studied how phorbol 12,13-diacetate (PDA) modulates mechanical responses of the tissue to methylxanthines, isoprenaline and ryanodine. 2. Caffeine (10 microM-5 mM), theophylline (10 microM-5 mM) and isoprenaline (1 nM-1 microM), each inhibited the spontaneous tone of the trachea. Pretreatment with PDA (0.1-10 microM) converted relaxant responses to high concentrations of the methylxanthines into contractions. PDA produced no equivalent effect against isoprenaline. Pretreatment with verapamil (1 or 10 microM), nifedipine (0.1 microM) or incubation with Ca(2+)-free, EGTA (0.1 mM)-containing physiological salt solution (PSS) suppressed the contraction produced by caffeine or theophylline in PDA (5 microM)-treated tissues. 3. The ability of PDA (5 microM) to convert caffeine-induced relaxation into caffeine-induced contraction was retained in tissues pretreated with a combination of atropine (1 microM) and mepyramine (1 microM) and in tissues denuded of the airway epithelium. 4. Caffeine (10 microM-5 mM), theophylline (10 microM-5 mM) and isoprenaline (1 nM-1 microM), each relaxed trachea contracted with histamine (0.1 mM). The relaxation induced by caffeine, theophylline and isoprenaline was markedly reduced in the presence of PDA (5 microM) and the responses to high concentrations of caffeine and theophylline, but not those to isoprenaline, were reversed to contractions. Verapamil (10 microM) prevented the effects of PDA against caffeine- or theophylline-induced relaxation. 5. PDA (1 microM) enhanced the tracheal spasm produced by caffeine (10 mM) and theophylline (10 mM) in indomethacin (2.8 microM)-treated trachea maintained at 20 degrees C. This enhancement was reduced in the presence of verapamil (10 microM). 6. Tested in trachea bathed by K+-rich (40 mM), Ca2+-free PSS, CaCl2 (0.1-20 mM) caused concentration-dependent spasm. PDA (1-5 MicroM) did not significantly modify the shape or position of the log concentration-effect curve for CaCl2. In contrast, verapamil (1 and 10 MicroM) antagonized CaCl2.7. Tested in trachea bathed by indomethacin (2.8 MicroM)-containing PSS, ryanodine (1-100 MicroM) caused concentration-dependent spasm. PDA (5 MicroM) potentiated ryanodine. Verapamil (10 MicroM) inhibited ryanodine in inducing spasm and suppressed the ability of PDA to potentiate ryanodine.8. It is concluded that, in guinea-pig isolated trachea, PDA augments the spasmogenic activity of the methylxanthines and ryanodine. This effect of PDA does not result from PDA-induced suppression of spontaneous tone, from increased cellular entry of Ca2+ through L-type channels or from sensitization of the intracellular contractile machinery to activator Ca2+. The evidence suggests, instead, that PDA facilitates methylxanthine- or ryanodine-induced release of Ca2+ from the intracellular store.

Animals↗
PubMed2005

Entrapment neuropathy in patients with spastic cerebral palsy.

OBJECTIVES: We performed nerve conduction and needle electromyographic tests in 29 patients with spastic cerebral palsy (SCP) and severe limb deformities. Nerve conduction abnormalities were detected in 32 of 400 sensory or motor nerves, while 11 of 29 patients (37.9%) showed abnormal nerve conduction, indicating one or more entrapment neuropathies. Patients with SCP develop severe joint contractures and deformities due to spastic muscle tone and limited muscle and joint use/flexibility; these contractures and deformities can, in turn, cause nerve damage, possibly as a result of the stretching, angulation or compression mechanisms in the anatomic fibro-osseous passages, where nerves are particularly susceptible.

Adolescent↗