Biomedical subjects

R O Laferte

Publications and source records attributed to R O Laferte.

12 recordsLinked to original sources

PubMed1981

Studies of enuresis. IX. Evidence of a mild form of compensated detrusor hyperreflexia in enuretic children.

We studied 41 consecutive enuretic boys and girls by supine cystometry followed by a cystometrogram in the standing position. The micturition stop test was performed on 30 of the 41 patients. The standard cystometrogram proved to be superior to the supine study in detecting stage II (overt) detrusor hyperreflexia. Furthermore, the stop test effectively demonstrated the presence of stage I (compensated) hyperreflexia, a mild degree of detrusor unsubstantiated but assumed to be present in many children with simple enuresis. Stage I detrusor hyperreflexia may now be defined clinically by normal standing and supine cystometrograms, and a positive micturition stop test.

Child↗

PubMed1980

Incontinence of urine due to instability of micturition reflexes: Part I. Detrusor reflex instability.

Micturition reflex instability may result from malfunction of the detrusor reflex or instability of the pudendal nucleus which innervates the pelvic floor muscles and external sphincter. Detrusor instability is the result of sacral micturition reflex center (SMRC) hyperexcitability. This may be caused by underinhibition or overfacilitation of the SMRC, and there are both central and peripheral causes of each. Detrusor hypertrophy may invoke chronic overactivity of the detrusodetrusor facilitative reflex causing SMRC overfacilitation. Similarly, distal urethral stricture and/or chronic urethritis causing chronic overactivity of the urethrodetrusor facilitative reflex is a common cause of SMRC overfacilitation. Pathologic relaxation and weakness of the striated muscles of the pelvic floor and perineum resulting in underactivity of the perineodetrusor inhibitory reflex, is a common cause of SMRC underinhibition. In adult women these factors often coexist. Each may predispose to stress-induced detrusor instability and are often seen in association with, or are confused with, true stress incontinence. The distinguishing characteristics of detrusor hypertonicity and detrusor hyperreflexia are reviewed, and the various mechanisms of pseudostress incontinence and of urgency incontinence are discussed in detail.

Adult↗

PubMed1980

Incontinence of urine due to instability of micturition reflexes. Part II. Pudendal nucleus instability.

Overinhibition or underfacilitation of the pudendal nucleus may cause profound involuntary relaxation of the striated muscles of the pelvic floor and perineum, including the "external" striated urethral sphincter. Pudendal nucleus instability may adversely affect urethral closure pressure and preclude a successful voluntary "recovery" effort to limit stress incontinence. It may also result in the involuntary loss of an important source of inhibition to the sacral micturition reflex center, which can lead to detrusor instability. The bilateral reciprocal relationship which exists between the detrusor reflex and the pelvic floor muscle tonus is fundamental to micturition instability syndromes. In this article, the pathophysiology of interaction of pudendal nucleus instability, detrusor reflex instability, and stress is described, and the importance of careful diagnostic evaluation of each case of incontinence is emphasized.

Electromyography↗

PubMed1977

Studies of enuresis. VIII. Detrusor and sphincter instability caused by overactivity of integral voiding reflexes.

Ninety-one children with nocturnal enuresis or enuresis plus daytime urgency incontinence were studied by cystometry. Seventy-two per cent of the girls and 62 per cent of the boys had evidence of bladder instability. Sixty-eight children in whom abnormalities were found on preliminary voiding urodynamics or voiding cystourethrography also underwent calibration and endoscopic examination under anesthesia. An atropine-suppression test was also performed preoperatively in some children with a markedly unstable bladder demonstrated on preoperative cystometry. In the majority of children tested suppression of bladder instability with atropine was demonstrable. Voluntary detrusor sphincter dyssynergia was demonstrated in a majority of the children with daytime urgency incontinence. Sixty-five per cent of the boys and 81 per cent of the girls were treated for urethral obstructive lesions suspected to be of functional urodynamic significance. Postoperative cystometry showed marked improvement in bladder stability in 57 per cent of the girls and 63 per cent of the boys treated for suspected urethral obstructive pathology. The anticholinergic suppression test was found to have no significant predictive value relative to the cause or surgical curability of bladder instability. The pathophysiologic significance of overactivity of integral voiding reflexes 6 through 11 is described.

Child↗

PubMed1977

Integral storage and voiding reflexes. Neurophysiologic concept of continence and micturition.

It is a common clinical misconception to regard the spinal micturition reflex center as fundamentally overactive and dependent on cerebral inhibition. Initiation and cessation of micturition is simplistically viewed as a manifestation of voluntary withdrawal and resumption of inhibitory corticospinal "regulation''. This view is in conflict with basic neurophysiologic experimental data. Actually, the organization of the micturition reflex is extremely complex. It is affected by multiple sources of facilitative and inhibitory influence, peripheral as well as central. During the past half century, at least twelve reflexes involved in urine storage and coordinated micturition have been described by various neurologic investigators. In this article the integral reflexes are identified and described. A functional organization of the integral reflexes which includes a modern concept of their role in the physiology of urine storage and micturition is presented. It is implicit that overactivity or functional failure of any one or combination of the integral reflexes may cause a significant disorder of lower urinary tract function.

Humans↗

PubMed1977

Overactivity of the integral storage and voiding reflexes in the juvenile urinary incontinence syndrome.

The physiologic importance of 12 integral storage and voiding reflexes has not been generally recognized and appreciated by clinicians. Pathologic overactivity of reflexes No. 9 and No. 10, the urethrodetrusor facilitatory reflexes, appears to be a very common factor in the etiology of the juvenile incontinence syndrome. Mild but urodynamically significant obstructive lesions of the distal urethra are a common predisposing factor to chronic urethritis and are potentially remediable by simple surgical procedures. Cystometric as well as symptomatic improvement is commonly observed postoperatively. The micturition reflex is extremely complex. Its excitability is dependent upon the balance of multiple vectors of both facilitatory and inhibitory influence from many sources, peripheral as well as central. The popular clinical concept of "uninhibited neurogenic bladder," based on the cystometrogram, is naive and simplistic. It deserves to be replaced by the term "unstable bladder" which acknowledges the neurologic and urologic complexities of micturition reflex instability and introduces no erroneous connotations as to the cause and potential treatability of an incontinence condition.

Afferent Pathways↗

PubMed1974