High Spinal Cord Lesions Research Articles

Severity of the neurological deficit of high spinal cord lesions assessed according to etiology

Spinal cord injury (SCI) represents a major health problem, having significant consequences on motor and sensory function, as well as on the quality of life of affected patients. The objective of this study is to assess the severity of high post-traumatic spinal cord injuries depending on the age and gender of the patients and the manner of their etiology. We used useful tools for evaluating and classifying the severity of spinal cord injuries: ASIA classification, MAS and MTS score. This is a retrospective observational study included a number of 146 patients with various high spinal cord injuries whose diagnosis was confirmed by imaging. The mean age of the cohort was 42.97 ± 15.9 years, with a range of 18 to 83 years. The severity of the ASIA score was inversely proportional to the age of the patients. Patients with ASIA A were younger than those with ASIA D. Regarding the etiology of the trauma, most patients, 39.7%, were traumatized following a road accident. The etiology of trauma has a significant influence on the severity of spinal cord injury. Accidents are the leading cause of injury, followed by falls and diving trauma. There is a correlation between the ASIA score and muscle tone/spasticity, which may influence the therapeutic approach and patient management.

Guillain-Barre Syndrome in High Tetraplegia Following Spinal Cord Lesion

Study design: A case report of Guillain–Barre Syndrome (GBS) variant presenting in a patient with high tetraplegia following cervical spinal cord lesion (C3-C6). Objective: To illustrate a clinical presentation of GBS in an individual with tetraplegia. Setting: Zhongnan Hospital of Wuhan University, Wuhan, China. Case presentation: A 55-year-old male with high spinal cord lesion at the level of C3-C6, following an emergency posterior cervical instrumentation and fusion with decompression of C3-C6 vertebral bodies under general anesthesia, developed urinary incontinence and weakness of the limbs, and was admitted to our facility for tetraplegia. Two months after admission, the patient had a sudden onset of fever (T40.0C) for which blood culture was done, and antibiotics were administered to sub side the fever. A few days later, the patient’s previously noted weakness progressed. A nerve conduction study was performed, which revealed severe axonal polyneuropathy affecting motor and sensory nerve fibers, prompting a diagnosis of acute motor-sensory axonal neuropathy (a variant of Guillian-Barre syndrome). Electromyography (EMG) reports indicated abnormal spontaneous activity in all limb muscles. An emergency Lumbar Puncture (LP) was performed which revealed the classical sign of albuminocytological disassociation of cerebrospinal fluid. GBS was diagnosed, but since the patient had pre-existing tetraplegia, autonomic dysfunction and was ventilated, the diagnosis was overshadowed and unfortunately delayed. Nevertheless, treatment modalities for both tetraplegia and GBS were initiated. There was a significant improvement in all extremities, but the bilateral decrease in the lower limbs muscle tone persisted. However, the patient refused to perform a repeat LP and was discharged three months later, under the requisite for regular follow-up. Conclusion: A careful neurological assessment prompted the diagnosis of acute polyradiculoneuropathy in a chronic patient with tetraplegia. It demonstrates how, in this population, an otherwise uncomplicated diagnosis of GBS can easily be missed. A deeper understanding of the cause and necessity for a subsequent therapeutic intervention in potentially life-threatening autonomic instability was understood via these signs.

Occipital neuralgia associates with high cervical spinal cord lesions in idiopathic inflammatory demyelinating disease

The association of trigeminal neuralgia with pontine lesions has been well documented in multiple sclerosis, and we tested the hypothesis that occipital neuralgia in multiple sclerosis is associated with high cervical spinal cord lesions. We retrospectively reviewed the records of 29 patients diagnosed with both occipital neuralgia and demyelinating disease by a neurologist from January 2001 to December 2014. We collected data on demographics, clinical findings, presence of C2-3 demyelinating lesions, and treatment responses. The patients with both occipital neuralgia and multiple sclerosis were typically female (76%) and had a later onset (age > 40) of occipital neuralgia (72%). Eighteen patients (64%) had the presence of C2-3 lesions and the majority had unilateral symptoms (83%) or episodic pain (78%). All patients with documented sensory loss (3/3) had C2-3 lesions. Most patients with progressive multiple sclerosis (6/8) had C2-3 lesions. Of the eight patients with C2-3 lesions and imaging at onset of occipital neuralgia, five (62.5%) had evidence of active demyelination. None of the patients with progressive multiple sclerosis (3/3) responded to occipital nerve blocks or high dose intravenous steroids, whereas all of the other phenotypes with long term follow-up (eight patients) had good responses. A cervical spine MRI should be considered in all patients presenting with occipital neuralgia. In patients with multiple sclerosis, clinical features in occipital neuralgia that were predictive of the presence of a C2-3 lesion were unilateral episodic symptoms, sensory loss, later onset of occipital neuralgia, and progressive multiple sclerosis phenotype. Clinical phenotype predicted response to treatment.

Aquaporin-4 antibodies, CNS acidosis and neuromyelitis optica: A potential link

BackgroundNeuromyelitis optica (NMO, Devic’s syndrome) is a severely disabling disorder of the central nervous system characterized by optic neuritis and longitudinally extensive myelitis. In around 80% of cases, NMO is caused by autoantibodies to astrocytic aquaporin-4 (AQP4), the most abundant water channel in the CNS. Acute NMO attacks are frequently accompanied by elevated levels of lactate in the cerebrospinal fluid (CSF). As a strongly dissociated anion (pK′=3.7) directly changing the strong ion difference, lactate causes a reduction in the dependent anion [HCO3-] and a rise in [H+], resulting in “metabolic” acidosis in the CSF. CSF acidosis also develops during respiratory failure due to brainstem or high cervical spinal cord lesions, the most common cause of death in NMO. However, lactic acid and more generally, a decrease in pH, has been shown to increase the membrane expression of AQP4 in astrocytes. An increase in AQP4 membrane expression during acute NMO attacks could potentially enhance the complement-mediated humoral immune reaction against AQP4-expressing astrocytes characteristic for NMO and, thus, result in more severe astrocytic damage. Moreover, lactate and acidosis have been shown to cause astrocytic swelling and to affect astrocytic viability, potentially rendering astrocytes more susceptible to AQP4-Ab-mediated damage. Finally, increased AQP4 expression could be an independent risk factor in NMO and other forms of CNS inflammation, as indicated by the finding of grossly attenuated experimental autoimmune encephalomyelitis in AQP4-null mice. Therefore, we hypothesize that CSF acidosis might play a role in the pathophysiology of AQP4-Ab-positive NMO and that alterations in CSF pH might possibly influence the outcome of acute attacks in this condition. In addition, we discuss potential clinical implications and make proposals on how to test the hypothesis. Finally, other factors that influence astrocytic AQP4 membrane expression and might play a role in NMO are discussed.

The treatment of neurogenic bladder dysfunction in patients with spinal cord injury

Neurogenic bladder dysfunction, resulted from demage to the neural structures in spinal lesion present a major problem for the patient, his environment and health care workers. Proper diagnosis of neurogenic bladder dysfunction allows you to implement appropriate treatment plan that will allow adequate emptying and prevention of complications that may endanger the patient's life. The evolution of spinal cord injuries can distinguish three phases: 1) spinal shock phase, 2) the recovery phase, 3) final phase. After spinal trauma bladder is affected mostly in two ways: 1) Spastic (reflex) bladder caused in lesion above voiding center (S2-S4 segments), 2) Flaccid (atonic) neuropathic bladder emerges in lesion at the voiding center (S2-S4) or below it, as well as lesions of the peripheral innervation of bladder, 3) Autonomic disreflection syndrome develops in patient with cervical or high thoracic spinal cord lesions, above the Th 1 segment, 4) Uninhibited neurogenic bladder develops in incomplete nerve pathway lesions in cerebral cortex, pyramidal pathway or in spinal cord-cerebral voiding control debilitate. The diagnosis of neurogenic bladder dysfunction is established by urodynamic examination, laboratory blood and urine findings as well as radiographic, computed tomography and nuclear magnetic resonance imaging of the spinal column. Bladder emptyng can be made by intermitetnt catheterization, Crede's procedure, suprapubic stimulation, smooth bladder muscle electrostimulation and by medications. The necessity of an Interdisciplinary approach to the treatment of these patients indicates all hardness in spinal cord injury patientes and consequent bladder dysfuncion.

Dorsal spinal cord injury as a cause of recurrent asystole requiring permanent cardiac pacing

Numerous unusual causes of atrioventricular block (AVB) with cardiac pacemaker implantation have been documented including cough, deglutition, or other vagally mediated mechanism. In spinal cord lesions, only high cervical spinal cord lesion has been reported as a cause of severe bradycardia. We report a case with not cervical but dorsal vertebral trauma and persistent paroxysmal AVB requiring cardiac pacemaker implantation.

Upper cervical intramedullary spinal metastasis of ovarian carcinoma: a case report and review of the literature

IntroductionCurrently there is no generalized approach to treating patients with intra-medullary spinal metastasis. High cervical spinal cord lesions can be particularly challenging cases, and may even be considered inoperable by some.Case reportWe present what is, to the best of our knowledge, the first reported case of ovarian carcinoma (managed primarily with surgery) in a 65-year-old Caucasian woman metastasizing to the upper cervical spinal cord; we also review the relevant literature and discuss management strategies.ConclusionsDue to improving systemic cancer therapies, patients with cancer now often survive longer and are more likely to develop central nervous system metastases. Therefore, neurosurgical oncologists are often challenged with difficult decisions about how to surgically manage these patients. We recommend individualized multidisciplinary management based on patient functional status, the need for definitive diagnosis for possible additional adjuvant therapies, and consideration of extent of systemic disease impacting on desirable quality and length of survival.

Systemic Administration of Rolipram Increases Medullary and Spinal cAMP and Activates a Latent Respiratory Motor Pathway After High Cervical Spinal Cord Injury

Background/Objective: High cervical spinal cord hemisection interrupts descending respiratory drive from the rostral ventral respiratory group in the medulla to the ipsilateral phrenic motoneurons. Hemisection results in the paralysis of the ipsilateral hemidiaphragm. Chronic administration of rolipram, a specific phosphodiesterase-IV inhibitor, promotes synaptic plasticity and restores phrenic nerve function after a high cervical spinal cord lesion. Here, we test the hypothesis that an acute administration of rolipram will increase spinal and medullary levels of 3′,5′-cyclic adenosine monophosphate (cAMP) and induce phrenic nerve recovery after cervical (C2) spinal cord hemisection.Methods: Male Sprague-Dawley rats were subjected to left C2 hemisection surgery 1 week before experimentation. Bilateral phrenic nerve activity was recorded in anesthetized, vagotomized, and pancuronium paralyzed rats, and rolipram was intravenously applied (2 mg/kg).Results: Intravenous administration of rolipram increased phrenic nerve output in uninjured control and left C2 spinal cord-hemisected rats. In addition, rolipram restored respiratory-related activity to the left phrenic nerve made quiescent by the hemisection. In both uninjured and hemisected rats, rolipram significantly enhanced phrenic inspiratory burst amplitude and burst area compared with predrug values. Also, rolipram concomitantly increased spinal and medullary cAMP.Conclusions: These results suggest that a phosphodiesterase inhibitor capable of elevating cAMP levels can enhance phrenic nerve output and restore respiratory-related phrenic nerve function after high cervical spinal cord injury. Thus, targeting the cAMP signaling cascade can be a useful therapeutic approach in promoting synaptic efficacy and respiratory recovery after cervical spinal cord injury.

Effect of caffeine on the neuromuscular system — potential as an ergogenic aid

The ergogenic effect of caffeine on endurance exercise performance is multifactorial; however, there is evidence for an effect on both the central nervous system and the excitation-contraction coupling of skeletal muscle. The increase in exercise performance seen following intracerebroventrical caffeine injection in rats provides strong evidence for a central ergogenic effect. The central ergogenic effect is not likely related to the ability of caffeine to promote wakefulness, but could be due to an increase in the pain and effort perception threshold. There is no evidence that caffeine alters peripheral nerve conduction velocity or neuromuscular transmission, and 1 study showed that motor unit synchronization was not altered by caffeine. Studies have also shown that caffeine can have a direct effect on skeletal muscle that could be ergogenic. For example, patients with high cervical spinal cord lesions showed improvements in stimulated contractile force during cycling, in spite of the fact that they have no peripheral pain input and no sympathetic nervous system response. Two studies have found a potentiation of force production during submaximal stimulation intensities, and 1 found that the M-wave amplitude was not altered by caffeine. Together, these studies suggest that caffeine can enhance contractile force during submaximal contractions by potentiating calcium release from the ryanodine receptor, not by altering sarcoplasmic excitability. Furthermore, the potentiation of force during submaximal electrical stimulation is identical in habitual and nonhabitual caffeine consumers. In summary, the ergogenic effects of caffeine during endurance activity are mediated partly by enhanced contractile force and partly by a reduction in perceived exertion, possibly though a blunting of effort and (or) pain.

Manifestaciones urológicas de los accidentes vásculo-medulares

IntroductionSpinal cord ischemia is a circulatory disorder of acute or subacute establishment and neurological clinic of medullar section, usually incomplete. We describe clinical and anatomical characteristics, as well as diagnostic methods and therapeuthic used in these patients. Material and methodssince 1987 to 2007, 65 patients were diagnosed of spinal cord ischemia in our hospital. Clinical interview, neurological examination and image study were performed. Urodynamic study was performed after medullar shock phase, including cystometry, pressure flow study and external urinary sphincter electromyography. We have reviewed treatment applied in these patients. Results65 patients (27 women and 38 men), median age 63 years (15-87). 28 patients (43%) presented high lesion (upper to T7), 32 (49%) middle (T7-L2) and 4 (6%) low lesion (below L2). Flaccid paraplegia and acute urinary retention were the most frequent clinical findings at the begining. Aetiology was determined mainly by Magnetic Resonance. Urodynamic study revealed: 9 patients (47,4%) with high spinal cord lesion and detrusor overactivity (with or without dyssynergia), and 6 (31,5%) with arreflexia; 11 patients (47,8%) with middle spinal cord lesion and detrusor overactivity and 7 patients with arreflexia (30,4%); one patient with low spinal cord lesion and detrusor overactivity, and another one with arreflexia (33%). Conclusionsthere is a good correlation among lesion level and clinical findings in traumatic spinal cord injuries, but this is not the same in spinal cord ischemia. Probably, incomplete and patched lesions in vascular spinal cord injuries could explain this lack of correlation. Therefore, it is mandatory to performe an exhaustive neurological and urological evaluation of these patients in order to select the best treatment and prevent upper urinary tract damage in the future.

Brain-computer interfaces: communication and restoration of movement in paralysis.

The review describes the status of brain-computer or brain-machine interface research. We focus on non-invasive brain-computer interfaces (BCIs) and their clinical utility for direct brain communication in paralysis and motor restoration in stroke. A large gap between the promises of invasive animal and human BCI preparations and the clinical reality characterizes the literature: while intact monkeys learn to execute more or less complex upper limb movements with spike patterns from motor brain regions alone without concomitant peripheral motor activity usually after extensive training, clinical applications in human diseases such as amyotrophic lateral sclerosis and paralysis from stroke or spinal cord lesions show only limited success, with the exception of verbal communication in paralysed and locked-in patients. BCIs based on electroencephalographic potentials or oscillations are ready to undergo large clinical studies and commercial production as an adjunct or a major assisted communication device for paralysed and locked-in patients. However, attempts to train completely locked-in patients with BCI communication after entering the complete locked-in state with no remaining eye movement failed. We propose that a lack of contingencies between goal directed thoughts and intentions may be at the heart of this problem. Experiments with chronically curarized rats support our hypothesis; operant conditioning and voluntary control of autonomic physiological functions turned out to be impossible in this preparation. In addition to assisted communication, BCIs consisting of operant learning of EEG slow cortical potentials and sensorimotor rhythm were demonstrated to be successful in drug resistant focal epilepsy and attention deficit disorder. First studies of non-invasive BCIs using sensorimotor rhythm of the EEG and MEG in restoration of paralysed hand movements in chronic stroke and single cases of high spinal cord lesions show some promise, but need extensive evaluation in well-controlled experiments. Invasive BMIs based on neuronal spike patterns, local field potentials or electrocorticogram may constitute the strategy of choice in severe cases of stroke and spinal cord paralysis. Future directions of BCI research should include the regulation of brain metabolism and blood flow and electrical and magnetic stimulation of the human brain (invasive and non-invasive). A series of studies using BOLD response regulation with functional magnetic resonance imaging (fMRI) and near infrared spectroscopy demonstrated a tight correlation between voluntary changes in brain metabolism and behaviour.

The feasibility of sleep assessment by actigraph in patients with tetraplegia

Sleep disturbances are frequent in patients with high spinal cord lesions, and are difficult to diagnose by means of polysomnography (PSG). Retrospective cohort study. Examine the feasibility of sleep assessment by actigraph in patients with tetraplegia. A rehabilitation center in Israel. Twenty-one patients with tetraplegia and 20 healthy persons. Sleep assessment by actigraphs attached to the head and the wrist. The actigraphic movement index (MI), total sleep time (TST), sleep efficiency (SE), wake after sleep onset (WASO), sleep latency (SL), and number of awakenings (NOA). In the control group actigraphy showed that during sleep the hand moves more than the head but that the movements were highly correlated. In patients with tetraplegia below C(5)-C(7) the hand also moved more than the head, but in patients with tetraplegia below C(4), the head moved more (P<0.05). No significant differences were found between patients with C(5)-C(7) tetraplegia and healthy controls in the sleep indices obtained by hand movements, or between patients with C(4) tetraplegia and healthy controls in the indices obtained by head movements. Control subjects and patients showed similar subjective assessment of sleep quality. These preliminary findings support the validity of wrist actigraphy for sleep assessment in patients with C(5)-C(7) tetraplegia, and suggest that head-mounted actigraphy is a feasible alternative for sleep assessment in patients with tetraplegia below C(4). To establish these findings, further investigations are required, with a larger number of patients and comparison with PSG.

Breaking the silence: Brain–computer interfaces (BCI) for communication and motor control

Brain-computer interfaces (BCI) allow control of computers or external devices with regulation of brain activity alone. Invasive BCIs, almost exclusively investigated in animal models using implanted electrodes in brain tissue, and noninvasive BCIs using electrophysiological recordings in humans are described. Clinical applications were reserved with few exceptions for the noninvasive approach: communication with the completely paralyzed and locked-in syndrome with slow cortical potentials, sensorimotor rhythm and P300, and restoration of movement and cortical reorganization in high spinal cord lesions and chronic stroke. It was demonstrated that noninvasive EEG-based BCIs allow brain-derived communication in paralyzed and locked-in patients but not in completely locked-in patients. At present no firm conclusion about the clinical utility of BCI for the control of voluntary movement can be made. Invasive multielectrode BCIs in otherwise healthy animals allowed execution of reaching, grasping, and force variations based on spike patterns and extracellular field potentials. The newly developed fMRI-BCIs and NIRS-BCIs, like EEG BCIs, offer promise for the learned regulation of emotional disorders and also disorders of young children.

EEG-based neuroprosthesis control: A step towards clinical practice

This case study demonstrates the coupling of an electroencephalogram (EEG)-based Brain–Computer Interface (BCI) with an implanted neuroprosthesis (Freehand ® system). Because the patient was available for only 3 days, the goal was to demonstrate the possibility of a patient gaining control over the motor imagery-based Graz BCI system within a very short training period. By applying himself to an organized and coordinated training procedure, the patient was able to generate distinctive EEG-patterns by the imagination of movements of his paralyzed left hand. These patterns consisted of power decreases in specific frequency bands that could be classified by the BCI. The output signal of the BCI emulated the shoulder joystick usually used, and by consecutive imaginations the patient was able to switch between different grasp phases of the lateral grasp that the Freehand ® system provided. By performing a part of the grasp-release test, the patient was able to move a simple object from one place to another. The results presented in this work give evidence that Brain–Computer Interfaces are an option for the control of neuroprostheses in patients with high spinal cord lesions. The fact that the user learned to control the BCI in a comparatively short time indicates that this method may also be an alternative approach for clinical purposes.

Safety and efficacy of percutaneous nephrolithotomy in patients with neurogenic bladder dysfunction

Objectives To review our experience performing percutaneous nephrolithotomy (PNL) on patients with neurogenic bladder dysfunction with special attention paid to the risks of surgical complications and stone recurrence. Patients with neurogenic bladder dysfunction with or without urinary diversion are at increased risk of urolithiasis, surgical complications, and recurrent stone disease. Methods We retrospectively reviewed the 23 patients with neurogenic bladder dysfunction who underwent PNL at our institution. Neurologic lesions included spina bifida, traumatic spinal cord injury, exstrophy/epispadias, neonatal meningitis, stroke, and spine chondrosarcoma. Bladder management included ileal conduit (n = 8), intermittent catheterization (n = 7), indwelling catheter (n = 7), and ureterosigmoidostomy (n = 1). Results We performed 100 procedures on 47 renal units (17 bilateral, 7 with recurrent stones). Urinary tract infection/colonization was seen in 21 of 23 patients, most of whom had more than one organism. The stone-free rate was 96%. Six patients required three or more procedures, each had a complete staghorn calculus. In an average of 36 months of follow-up, 10 patients (46%) had recurrent stone disease requiring intervention, and 5 patients (23%) underwent repeat PNL. The stone composition analysis revealed mainly infection-related stones. Conclusions PNL in patients with neurogenic voiding dysfunction is safe and effective, with outcomes comparable to that of patients without such lesions. The complication rate is small but statistically significant. It is important to obtain adequate urine cultures, because renal pelvis and bladder culture data may differ and affect the outcome. Risk factors for recurrent stone disease include a high spinal cord lesion, indwelling urinary catheter, and ureterosigmoidostomy.

Flow-by induced hypoventilation in high spinal cord lesions--report of two casesdagger

Flow-by induced hypoventilation in high spinal cord lesions--report of two casesdagger

Continuous Noninvasive Ventilation for Patients with Neuromuscular Disease and Spinal Cord Injury

Patients with a variety of neuromuscular diseases including quadraplegia due to high spinal cord lesions can be managed with full-time noninvasive ventilation instead of intermittent positive pressure ventilation (IPPV) via a tracheostomy. This approach is not suitable for patients with severe bulbar involvement. To be successful with full-time noninvasive IPPV, the ventilator user must realize three goals. First, respiratory system compliance should be optimized and maintained by frequent full inflations delivered by stacking breaths from a volume-cycled ventilator or by insufflating air at adequate pressures using a mechanical insufflator-exsufflator. Second, normal levels of alveolar ventilation are sustained using a variety of noninvasive approaches, including nasal, oronasal, or mouthpiece interfaces. Third, patients must be taught to use techniques and devices to enhance cough, particularly the mechanical insufflator-exsufflator. When these goals are met, noninvasive NPPV can offer patients greater comfort, simpler and more convenient ventilator use, and reduced rates of infections, complications, and hospitalizations as compared with tracheostomy IPPV.

Treatment of Autonomic Hyperreflexia in a Quadriplegic Patient by Epidural Anesthesia in the Postoperative Period

Treatment of Autonomic Hyperreflexia in a Quadriplegic Patient by Epidural Anesthesia in the Postoperative Period

Cardiovascular response to the DIBEX manoeuvre: Practical applications

We developed the DIBEX manoeuvre to study vasoconstriction performance in man. DIBEX stands for: Deep Inspiration, Breath-holding against a closed glottis while relaxing thoracic and abdominal muscles, no straining, and after 40 s Expiration. This manoeuvre provokes an instant reduction in venous return and consequently a large drop in arterial pressure, 40 s later followed by an inverse step wise increase in venous return. We evaluated in two separate studies the extent by the DIBEX manoeuvre which reveals vasoconstriction performance: (1) under the influence of ketanserin, (2) in the presence of a high spinal cord lesion. With informed consent and approval by the ethical committee of the Vrije Universiteit Ziekenhuis Amsterdam two studies were performed. Study (1) 2 × 5 mg of ketanserin was administered i.v. to seven healthy volunteer subjects with a time interval of 5 min. The DIBEX manoeuvre was performed in the standing position before and 30 min after the administration of ketanserin. Study (2) 10 quadriplegic subjects performed the DIBEX manoeuvre in sitting position. In both studies beat-to-beat blood pressure (BP) was measured noninvasively with the Finapres™, the heart rate (HR) was also recorded. Study (1) In agreement with previous data ketanserin did not affect HR. Thirty min after the administration of ketanserin there was no significant difference in BP. Before ketanserin during the DIBEX manoeuvre, systolic BP dropped within 6–8 beats by 40–60 mmHg. After 10–20 s BP reached a new steady state just below control level, due to the intact baroflex control. After breath release, the control group showed a large BP overshoot, due to pooled venous blood now pumped into the constricted arterial system. An immediate and strong reflex bradycardia compensated the BP rise. After the administration of ketanserin, BP also showed the initial step wise fall, but BP remained low. Three volunteers even fainted at the end of the DIBEX manoeuvre. After breath release there was no BP overshoot. Study (2) In the quadriplegic group BP also showed the initial step wise fall, and BP remained low. After breath release, BP and HR returned to the base levels without overshoots, due to an absence of vasoconstriction. Ketanserin does not affect the cardiac baroreflex and has no effects on basal haemodynamic responses in normal people under static conditions. However, in the case of a strong enough and prolonged BP decreasing stimulus, the vasoconstriction inhibiting effect of ketanserin could be demonstrated even in normal man. The DIBEX manoeuvre proves to be such a strong BP stimulus that a suppressed vasoconstriction leads to abnormal responses, and in some cases to (near) fainting. It also showed that in quadriplegic subjects the response to the DIBEX manoeuvre was very different when compared with control subjects, emphasizing the manoeuvres capability for testing sympathetic vasomotor control. These two practical applications of the DIBEX manoeuvre confirm that this manoeuvre is a very powerful test of vasoconstriction capacity in man.

The effect of levcromakalim (BRL 38227) on bladder function in patients with high spinal cord lesions.

The effects of the potassium channel opener levcromakalim (BRL 38227) 7.5 micrograms kg-1 were examined on urodynamic variables and blood pressure during inflow and voiding cystometry in six high spinal cord lesion patients. Levcromakalim administration significantly increased the duration of bladder contraction (197 +/- 128 s to 267 +/- 167 s, P < 0.05) and also reduced blood pressure (126 +/- 13/67 +/- 9 mm Hg to 104 +/- 25/52 +/- 12 mm Hg) but was without effect on other urodynamic parameters. Because of concerns about hypotensive responses, further studies involving higher doses of levcromakalim should be considered only if the drug was administered intravesically.