Kotaro Taniguchi

Radical Transurethral Resection of the Prostate in Male Paraplegics Revisited: Further Clinical Experience and Urodynamic Considerations for its Effectiveness

We report our experience with radical transurethral resection of the prostate performed on 89 male spinal cord injury subjects. The over-all success rate of modified sphincterotomy was 90 per cent, although there was a 14 per cent recurrence rate with time. Urodynamically, success was characterized by a statistically significant reduction in the degree of detrusor-sphincter dyssynergia, an increase in vesical compliance and a reduction in detrusor hyperreflexia. These results suggest an effect on the distal sphincteric area by the adrenergic system in the genesis of detrusor-sphincter dyssynergia. It is suggested that radical transurethral resection of the prostate exerts this effect via a surgical sympathectomy, while continence is preserved by the activity of the untouched external urethral sphincter.

Further Characterization of the External Urethral Sphincter in Spinal Cord Injury: Study during Spinal Shock and Evolution of Responsiveness to Alpha-Adrenergic Stimulation

To shed further insight into its ever evolving concepts, we studied the activity of the external urethral sphincter in patients with spinal cord injury. Study during the phase of acute spinal shock revealed persistent electromyographic activity in the external urethral sphincter and no activity in the external anal sphincter, suggesting the presence of functional dissociation between the 2 sphincters from the onset of acute spinal injury. The genesis of dissociated activity was discussed by reference to recent experiments on the individual differences in motor neuron and muscle subtypes. Only the external urethral sphincter of chronic paraplegics demonstrated a uniformly increased electromyographic activity after alpha-adrenergic stimulation, while the response in the external anal sphincter was variable. The mechanism of increased response to alpha-adrenergic stimulation in the denervated external urethral sphincter appears to reside either in direct postsynaptic stimulation or recruitment of motor neurons other than the somatic pudendal system, since pre-treatment with competitive muscle relaxant failed to block this increased response in the external urethral sphincter.

Peripheral factors contributing to the volitional control of firing rates of the human motor units

Human subjects can volitionally control discharge frequencies of isolated motor units at several frequencies. If the tonic firing rates such as 10 Hz are mainly dependent on the gamma-loop and if Xylocaine blocks gamma-fibers before blocking alpha-fibers, application of Xylocaine would preferentially disturb the tonic rates. After application of Xylocaine to the nerve innervating the motor units the tonic discharges at 10 Hz became irregular, while the phasic discharges at 1 Hz could still be performed volitionally. These results suggest that volitional control of tonic discharges of the motor units are dependent upon gamma activity, while the phasic discharges may be controlled by the impulses along the pyramidal tracts.

Neurogenic urethra: clinical relevance of isolated neuropathic dysfunction of the urethra, and the denervation supersensitivity of the urethra revisited.

Our clinical experience on isolated neuropathic dysfunction of the urethra is presented. By discussing the urodynamic findings in neurogenic urethra, wherein the denervation supersensitivity to alpha-adrenergic stimulation in the absence of vesical denervation was a common denominator, some insight into the modern concept of motor innervation of the urethra was attempted. Our data are supportive of the current dogma implicating a significant sympathetic contribution to both autonomic and somatomotor innervation of the urethra.

Presetting of excitability of the spinal Ia inhibitory pathway in relation to the direction of an intended movement.

The spinal Ia inhibitory pathway which reciprocally inhibits hindlimb extensor motoneurons was found to be potentiated when human subjects were prepared, but not initiated, to perform a quick dorsiflexion at the ankle in response to a somesthetic stimulus.

Wilms tumor and nephrotic syndrome in male pseudohermaphroditism

A case is reported of a child with male pseudohermaphroditism in whom Wilms tumor developed at age twenty-two months. The tumor was treated accordingly, but the child subsequently died of nephrotic syndrome with renal failure at age thirty-two months. After reviewing the similar concurrence of these disorders described as a syndrome, it was suggested that they may have basic embryologic abnormalities in common and that all of them originate during embryogenesis. The importance of bearing this syndrome in mind in the management of a child with abnormal gonadal differentiation is stressed.

Endourological evaluation and management of leukoplakia of the renal pelvis.

Since August 1989, we have seen 4 patients with leukoplakia of the renal pelvis associated with a longstanding renal stone. In 2 of them, excretory or retrograde pyelography revealed multiple filling defects in the left renal pelvis as well as a renal stone, although urine cytological examination was negative. One of the other 2 patients underwent extracorporeal shock wave lithotripsy (ESWL) for the renal stone, but this was not followed by the passage of stone fragments. The renal stone in the remaining patient was associated with staghorn calculi. For stone extraction as well as endoscopic evaluation of the intrapelvic lesion, percutaneous nephroscopy was performed. A small to large amount of tissue-like white debris in sheets characteristic of leukoplakia was found in the renal pelvis with stones embedded in it and was removed directly by forceps or suction and then by irrigating with saline. We propose that 1) the endourological approach should be recommended for patients with renal pelvic lesions associated with longstanding renal stones or for patients who show difficulty in passing stone fragments after ESWL and 2) this entity of leukoplakia should be kept in mind for the differential diagnosis of renal pelvic lesions associated with renal stones.