Peter A. Knapp

Impact of spinal cord injury on sexual health and quality of life

To provide a comprehensive insight into sexuality after spinal cord injury, 120 patients received a questionnaire to assess their sexual activities, abilities, desires, satisfaction and sexual adjustment after injury. In the 63 responding patients, spinal cord injury had a major impact on sexual function. Relationship to partner, social life, bladder management and physical well-being had a significant impact on quality of life. Relationship to partner, ability to move and mental well-being, as well as aspects of sexual desire and body image had a significant correlation to satisfaction with sexual life. In the studied population, there was no significant correlation between preserved sexual abilities after spinal cord injury and the satisfaction with sexual life.

Sympathetic sudomotor skin activity in human after complete spinal cord injury

Spinal cord injury (SCI) causes serious disturbances in autonomic innervation and malfunction of the sympathetic nervous system that controls the pelvic organs, blood pressure, skin temperature and sweating. We studied sympathetic sudomotor pathways in 6 healthy subjects and 14 patients with sensory and motor complete SCI on cervical, thoracic and lumbar level. Sympathetic skin responses (SSRs) were provoked by auditory bursts and electrical stimulation of median, pudendal and tibial nerve and recorded from the palmar and plantar skin. The SSRs in healthy subjects occurred generally with the same pattern and with similar latencies suggesting a common sudomotor pathway mediating the SSR. Appearance or absence of the SSRs in SCI following stimulation above the lesion depend on the spinal level of lesion and on the location of stimulation. Lesions below T3 show palmar and lesions below T12 palmar and plantar SSR. Pudendal nerve stimulation evoked plantar SSRs in patients with complete cervical and thoracic SCI. No SSRs were obtained in patients with lesions at L1 and more caudal. SSRs following pudendal nerve stimulation in complete SCI above the level L1 are mediated by sacral somatic afferents and a sympathetic pathway originating at the upper lumbar level. The underlying sacro-lumbar reflex circuit is organized on spinal level and requires intact lumbar segments. Tibial nerve stimulation was not found to elicit SSRs below a SCI lesion and we suppose that this type of electrical stimulation cannot activate the spinal sudomotor reflex circuit.

Electrophysiological Assessment of Sensations Arising from the Bladder: Are there Objective Criteria for Subjective Perceptions?

PURPOSE Initial bladder filling sensation, first and strong desire to void are subjective perceptions that occur periodically during the urine storage mode of bladder function, representing sensory input from the lower urinary tract. To our knowledge methods for evaluating sensory bladder function are not available. We studied a simple electrophysiological procedure for the objective assessment of bladder sensations using sympathetic skin responses and surface pelvic floor electromyography. MATERIALS AND METHODS Informed consent was provided by 8 healthy male subjects, who were administered 20 mg. furosemide and 1 l. fluid to drink. Palmar and plantar sympathetic skin responses, and surface pelvic floor electromyogram were continuously recorded during bladder filling, voluntary pelvic floor contraction and voiding. RESULTS First desire to void evoked simultaneous sympathetic skin responses and pelvic floor contractions. This pattern appeared periodically with the desire to void sensation as well as with strong desire to void at maximum bladder capacity and it correlated well with the subjective sensation of the subjects. Voluntary pelvic floor contraction decreased the subjective intensity of the desire to void sensation as well as sympathetic skin response activity for the same short period. During voiding sympathetic skin responses almost complete absence of sympathetic skin responses was observed. CONCLUSIONS Sensations arising from the bladder induce combined activation of sympathetic skin responses and pelvic floor activity. This coherence indicates synchronized activation and inactivation of the autonomic and somatic pathways necessary for appropriate urine storage and coordinated voiding. Our observations may introduce a new approach for objectively assessing subjective sensations arising from the urinary tract.

Sleep-related painful erections

Background A 45-year-old man presented with repeated awakenings at night caused by nocturnal painful erections, in sharp contrast with normal erections at other times, 2 years after surgical removal of a thoracic (Th6–7) ependymoma.Investigations Physical examination, pharmaco-sensitized penile Doppler ultrasound, spinal and brain MRI, neurophysiological work-up (tibial and perineal somatosensory-evoked potential; hand, foot and perineal sympathetic skin response assessment), polysomnography with recording of nocturnal penile tumescence.Diagnosis Sleep-related painful erections, characterized by penile pain during nocturnal erection, typically during rapid eye movement sleep, in the presence of a residual thoracic spinal cord syndrome.Management Amitriptyline, an antidepressant that suppresses rapid eye movement sleep, was ineffective. Treatments with other antidepressants, clozapine and beta-blockers were suggested, but the patient declined because of potential severe side effects.

The effect of passive cycling movements on spasticity after spinal cord injury: preliminary results.

Objective:To investigate the influence of rhythmic passive movements of the legs on the reduction of spasticity after spinal cord injury (SCI).Setting:Swiss Paraplegic Centre Nottwil, Switzerland.Methods:A total of 10 subjects with motor complete SCI were treated with a cycling device for half an hour. Before and after cycling their spasticity was tested with an isokinetic dynamometer. The subjects were tested one week later by exactly the same procedure with a half an hour break instead of the cycling. Subjects were asked about their spasticity before and after the cycling and break.Results:There was no significant difference in elicited peak torque either before and after the cycling, or before and after the break (MANOVA, P<0.05). Six out of 10 subjects estimated their spasticity as less after the cycling.Conclusion:With the isokinetic dynamometer, it was not possible to show an effect of passive cycling on spasticity reduction. However, six out of 10 of the subjects estimated their spasticity to be less after cycling. This positive effect might be attributed to a reduced spasticity in the trunk and/or to the attention the subjects perceived during the intervention.

Heart rate variability: an objective measure of autonomic activity and bladder sensations during urodynamics.

There are still controversies regarding the reproducibility of cystometric data and no objective measurement of bladder sensations is currently available. Additionally, very little information exists about autonomic activity during standard filling cystometry (FC). The aim of this study was to evaluate the use of heart rate variability (HRV) analysis as a reliable monitor of the autonomic nervous system and objective measure for bladder sensations during FC.

Autonomic dysreflexia in response to pudendal nerve stimulation

Study design: Pudendal nerve stimulation in complete spinal cord injury (SCI).Objective: To evaluate the influence of pudendal nerve stimulation on the cardiovascular system in SCI patients in order to assess the underlying neuronal mechanism and the potential risk during stimulation.Setting: Swiss Paraplegic Center, and University Hospital, Zurich.Methods: A total of 22 male patients with a complete SCI were divided into two groups according to the level of lesion: group A (C6–T6, n=15) and group B (T7–L2, n=7). A total of 66 stimulations using biphasic rectangular impulses (0.2 ms, 10 Hz) with intensities up to 100 mA were applied to the dorsal penile nerve. Of these, 15 stimulations in five patients were repeated after intravenous application of 7 mg of phentolamine. Heart rate (HR) and blood pressure (BP) were recorded by a Finapres® cuff applied to the right index finger.Results: Significant increased diastolic and systolic BP accompanied by significant decreased HR suggested the occurrence of autonomic dysreflexia (AD) during pudendal nerve stimulation. These cardiovascular changes corresponded with the subjective sensation of AD symptoms in patients of group A. Intravenous phentolamine lowered the resting BP and prevented severe hypertension during stimulation. Patients in group B presented with mild HR and BP changes in response to pudendal nerve stimulation and reported no AD symptoms.Conclusion: Our results show a considerable effect of electrical pudendal nerve stimulation on HR and BP in patients with high SCI. This may indicate that sacral somatic afferent fibers of the pudendal nerve are involved in the neuronal mechanism of AD in SCI patients with high neurological level. Intravenous phentolamine enables pudendal nerve stimulation without the risk of severe hypertension.

An update on the treatment of detrusor‐sphincter dyssynergia with botulinum toxin type A

The aim of this study was to evaluate the relaxant effect of two preparations (BOTOX® versus Dysport®) of botulinum toxin type A (BTX‐A) on the external urethral sphincter in patients with neurogenic voiding disorders. Ten male spinal cord injury patients with detrusor‐ external urethral sphincter dyssynergia (DSD) were clinically assessed before, and 4–6 weeks after, transurethral or transperineal BTX‐A injections (BOTOX® 100 U or Dysport® 250 U) into the external urethral sphincter. Patients with persistent difficulties in voiding or high post‐void residual volumes were re‐injected with the same product up to three times. All patients were urodynamically examined within 120 days of injection. In total, 30 BTX‐A injection cycles (one to three injections) were administered. Significant (P < 0.05) reductions in the DSD duration post‐injection, the time interval between the start of bladder contractions and voiding, and DSD seventy post‐treatment were observed. All patients who presented with a residual volume pre‐treatment showed a marked decrease post‐treatment. These effects lasted 6 months. Improvements in urodynamic parameters were significantly better following BOTOX® than DysporP treatment (P < 0.05), although the Dysport® dose used is now considered less potent than that of BOTOX®. Thus, injections of BTX‐A into the external urethral sphincter are a valuable treatment option for DSD in spinal cord injury patients. Treatment success appears to depend on the seventy of DSD before treatment.

Magnetic stimulation of sacral roots for assessing the efferent neuronal pathways of lower urinary tract

The value of sacral magnetic stimulation (SMS) in neurophysiological evaluation of the sacral efferent pathways of the lower urinary tract was assessed during urodynamic examination in 10 men with chronic suprasacral spinal cord injury (SCI) and in 7 healthy volunteers. Investigated parameters included latency and amplitude of the urodynamic pressure response of the external urethral sphincter and detrusor to different stimulation strengths (50–100%) and single or repetitive (20 and 30 Hz) stimuli. Following SMS, reproducible external urethral sphincter pressure responses (mean latency, 13 ms) were recorded in all subjects. In contrast, a detrusor pressure increase was recorded only in SCI patients after repetitive SMS, with a latency of 1–2 s. This implies the appearance of a polysynaptic spinal reflex due to changes in organization of the sacral micturition reflex after SCI. The method of SMS may be helpful for the evaluation of cases in which urodynamic studies remain inconclusive.

Autonomic hyperreflexia revisited

PURPOSE To analyze autonomic hyperreflexia (AHR) associated with neurogenic bladder dysfunction in high spinal cord-injured patients. MATERIAL AND METHODS Sixty-five patients were examined using a new recording system. Seventeen suffered from a spinal cord lesion above the T5-T6 level and presented with neurogenic voiding disorders and AHR. Mean arterial pressure (MAP) changes were analyzed during 3 different urodynamic phases: bladder filling; isometric bladder contraction, and voiding. RESULTS Of the 17 tetraplegic and high paraplegic patients, 6 dropped out and 11 entered the study. Nine of these eleven patients displayed uninhibited bladder contractions and voiding. In these 9 cases MAP increased progressively during bladder contraction until a maximal bladder pressure was reached. An ongoing elevation of MAP was observed during voiding which returned to normal values within 5 min after micturition. In 2 patients detrusor-sphincter dyssynergia prevented voiding. As opposed to the 9 previously mentioned patients, maximal MAP occurred at or before the maximal bladder pressure in these 2 cases and decreased thereafter. CONCLUSIONS Evidence is presented that the posterior urethral receptors and their ascending pathway played a major role in the maintenance of AHR during micturition.