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Biomedical subjects

A R Mundy

Publications and source records attributed to A R Mundy.

At least 109 records · Page 6Linked to original sources

Metabolic complications of cystoplasty.

A series of 48 patients with intestinal segments incorporated into the urinary tract underwent assessment of acid-base and electrolyte balance. All patients had abnormal blood gas analyses, usually a metabolic acidosis with respiratory compensation; 33% had hyperchloraemia. Radioisotope studies using sodium, potassium and bromine showed that all were absorbed and that absorption was unaffected by renal function. The results suggest that all such patients, but particularly women and children, may be at risk of the secondary effects of chronic acidosis, especially skeletal demineralisation, unless some compensatory mechanism is working to offset the effects of the acidosis.

Acidosis↗

The dissolution of urinary mucus after cystoplasty.

Three agents have been tested for mucolytic activity to prevent or treat difficulties in bladder emptying following augmentation and substitution cystoplasty, particularly in patients emptying by intermittent self-catheterisation. Carbocysteine produced precipitation of mucus, which was found not to be helpful. N-acetylcysteine and urea both dissolved mucus, but urea proved to be more effective.

Acetylcysteine↗

Assessment of the malignant potential of cystoplasty.

The study group comprised 34 patients with either an ileal augmentation cystoplasty or a colonic substitution cystoplasty. The histological appearance of the intestinal segment, suture line, bladder remnant and bacterial colonisation of the urine and urinary nitrosamine levels were recorded. There was a high incidence of histological abnormalities, the more significant of which correlated with heavy mixed bacterial growth on urine culture and with high levels of urinary N-nitrosamines. This group of compounds is thought to act as carcinogens in both bladder and bowel under certain circumstances. It was concluded that patients undergoing lower urinary tract reconstruction using intestinal segments should be considered at risk of developing malignant change either in the intestinal segment or in the bladder remnant. Close long-term follow-up of these patients is essential.

Adolescent↗

The treatment of sphincter strictures.

A group of 25 patients with strictures of the membranous urethra following transurethral resection of the prostate (TURP) were investigated and treated initially by careful urethral dilatation. This controlled the stricture in 14 patients, 6 of whom continued with occasional dilatation or self-catheterisation to maintain control; 8 required an artificial urinary sphincter (AUS) and 2 required a "clam" ileocystoplasty for detrusor instability. Eleven had persistent or recurrent strictures requiring urethroplasty. Nine underwent bulbo-prostatic anastomotic urethroplasty, 4 with simultaneous bladder neck reconstruction and 5 with subsequent implantation of an AUS; 2 had a preputial patch urethroplasty with subsequent implantation of an AUS. Four of the 9 patients with a urethroplasty and an AUS are satisfactory, 1 developed a recurrent stricture and 2 developed erosions. Two of those with a bulbo-prostatic anastomosis and bladder neck reconstruction are satisfactory and 2 are incontinent. These results were compared with those of 18 other patients who underwent bladder neck reconstruction and 12 who had a urethroplasty in conjunction with an AUS for reasons other than a post-TURP sphincter stricture. The success rate of bladder neck reconstruction was 55% and the success rate of urethroplasty in conjunction with an AUS was 83%, but the main complication of AUS implantation, erosion, was a more serious problem than failure of bladder neck reconstruction. However, the much higher success rate makes AUS implantation a more satisfactory procedure. Surgery should be avoided if at all possible and reliance placed on urethral dilatation.

Aged↗

The management of the neuropathic bladder in childhood.

The key factors in the management of the neuropathic bladder are an understanding of the pathophysiology and natural history of the bladder and urethral dysfunction, an understanding of the urodynamic investigation of such problems, and a realistic approach to treatment. Those children with good motivation, intelligence, mobility and manipulative skills can almost always be made continent by surgical means. Management otherwise is to control or contain incontinence as far as possible and to preserve upper tract function.

Adrenergic alpha-Agonists↗

A technique for total substitution of the lower urinary tract without the use of a prosthesis.

A technique is described for total replacement of the lower urinary tract in women in which a pedicled labial skin tube is created and anastomosed to a substitution cystoplasty with a submucosal tunnelled type of "anti-reflux" anastomosis which provides a continence mechanism. The patients thereafter void by intermittent self-catheterisation. This technique has been used in 6 women as part of total pelvic reconstruction for vesico-vagino-rectal fistula following radical radiotherapy, with or without a Wertheim's hysterectomy, for carcinoma of the cervix. A similar technique using a pedicled preputial/penile skin tube has been used in 2 men following a cystoprostato-urethrectomy for transitional cell carcinoma of the bladder.

Anastomosis, Surgical↗

Detrusor behaviour following implantation of the Brantley Scott artificial urinary sphincter for neuropathic incontinence.

During a 3-year period, 102 Brantley Scott artificial urinary sphincters were implanted to control urinary incontinence. Nineteen patients underwent endoscopic sphincterotomy and artificial sphincter implantation for the control of sphincter weakness incontinence due to congenital neuropathic bladder dysfunction. None had previous augmentation or substitution procedures. Nine patients (47%) subsequently showed a deterioration in detrusor function, resulting in either recurrent incontinence or upper tract dilatation. Eight of these (89%) had previously been shown to have an intermediate pattern of neuropathic bladder abnormality. All patients implanted with an AUS require long-term surveillance including videourodynamic studies, and patients with intermediate neuropathic bladders should be considered for augmentation or substitution at the time of implantation.

Adolescent↗

The problems of substitution cystoplasty.

Substitution cystoplasty was performed in 157 patients aged 4 to 71 years; 62% suffered no post-operative complication. The commonest complication was sphincter-weakness incontinence, found in 18%, mainly in patients having a cystoplasty for interstitial cystitis; it was rare for the patient to complain of this incontinence. Ten per cent suffered incontinence due to colonic overactivity and this occurred in patients with neuropathic sphincter-weakness incontinence or an artificial sphincter; all of these patients complained of their incontinence. This was corrected by "patching" in all cases. Voiding difficulties requiring clean intermittent self-catheterisation occurred in 15%. More worrying was the universal finding, when looked for by blood gas analysis, of a metabolic acidosis with respiratory compensation. It was concluded that in the absence of neuropathy, sphincter weakness or an artificial sphincter, an unmodified ileocaecal segment substitution cystoplasty is adequate; in the presence of neuropathy, sphincter weakness or an artificial sphincter, a "pouch" type of substitution cystoplasty should be performed. All patients should have blood gas analyses from time to time as part of their routine post-operative follow-up.

Acidosis↗

Pedicled preputial patch urethroplasty.

Pedicled preputial patch urethroplasty has been used in 48 patients for the treatment of urethral strictures that have not responded to endoscopic surgery. The procedure is simple to perform and almost universally applicable. It avoids the problems associated with the use of scrotal skin. Its wider use is recommended.

Follow-Up Studies↗

One hundred artificial sphincters.

One hundred patients with urinary incontinence of various aetiologies underwent implantation of an artificial urinary sphincter (AUS). In 40 patients various reconstructive procedures of the lower urinary tract were carried out at the same time. In 93 patients the results were successful and they are continent. Six are incontinent and 4 of these await AUS replacement. One patient has had a urinary diversion with the sphincter still in situ and functioning. The complication rate was 45% (of which 29% were designated "sphincter-related"). Half of these were accounted for by two complications: one was a change in bladder behaviour in patients with neuropathic bladders and the other was stress incontinence as a direct result of implanting low pressure devices. If these two factors and the "sphincter-unrelated" problems are discounted, the complication rate was 13%. The AUS is a satisfactory and successful method of treatment for sphincter weakness incontinence regardless of aetiology and the results suggest no contraindication to implantation at the same time as reconstructive surgery of the lower urinary tract.

Adolescent↗

Spinning top urethra: not a normal variant.

Spinning top urethra (STU) is a term used to describe a widened posterior urethra seen mainly in girls. It is commonly regarded as a normal variant. The authors studied 30 girls with STU using videourodynamics. Twenty-eight showed bladder instability; 21, a congenital wide bladder neck anomaly; and 20, both instability and a wide bladder neck. One patient had a sensitive bladder. All patients had a urodynamic abnormality. The authors believe that the STU is nearly always an indication of bladder instability or wide bladder neck anomaly. The most common mechanism for the dilatation of the posterior urethra is that unstable contractions are resisted by a voluntary increase in distal sphincter tension so as to prevent leakage of urine. The resulting pressure rise produces distention of the posterior urethra, which will be maximal in subjects with a weak bladder neck mechanism as in the congenital wide bladder neck anomaly. The authors believe that STU is seldom if ever a normal variant.

Adolescent↗

The "congenital" wide bladder neck anomaly: a common cause of incontinence in children.

In a study of 251 children (108 boys, 143 girls) undergoing videourodynamic studies for the assessment of non-neuropathic bladder dysfunction, 45 (19%) were found to have a wide bladder neck as their primary abnormality. Based on these studies there is evidence that the wide bladder neck anomaly is congenital in origin. In addition to producing significant urinary symptoms in childhood, this anomaly may provide a basis for stress incontinence in later life.

Adolescent↗

Pathophysiology of idiopathic detrusor instability and detrusor hyper-reflexia. An in vitro study of human detrusor muscle.

Muscle strips from urodynamically normal bladders and from bladders exhibiting idiopathic detrusor instability or detrusor hyper-reflexia were compared under isometric conditions in an organ bath. Spontaneous contractions developed more often in unstable and hyper-reflexic muscle and were of greater amplitude, frequency and basal tension. Electrical field stimulation caused a frequency-dependent contraction which was largely abolished by both tetrodotoxin (TTX) and atropine in all three muscle types. Comparison of their frequency response curves demonstrated a significantly greater sensitivity than that of unstable and hyper-reflexic muscle to low stimulation frequencies. Acetylcholine caused a dose-related contractile response in all muscle types. There were no significant differences between the dose response curves of unstable and hyper-reflexic muscle, and those of normal muscle. The results suggest that the pathophysiology of the involuntary detrusor contraction is common to both idiopathic detrusor instability and detrusor hyper-reflexia and that this is related to a disorder of an intrinsic neuromodulatory mechanism within the detrusor muscle.

Acetylcholine↗

Clam enterocystoplasty in the neuropathic bladder.

Clam enterocystoplasty has proved to be the most effective treatment for severe detrusor instability resistant to conservative treatment (Bramble, 1982; Mundy and Stephenson, 1985). More recently it has become the procedure of choice in patients with neuropathic bladders with hyper-reflexia or severely impaired compliance, provided that the bladder is of reasonable size and that gross fibrosis and/or diverticular formation of the bladder wall has not occurred. Fifty-nine patients have undergone the clam procedure as part or all of their reconstruction in the past 4 years. Although uncontrolled incontinence was the commonest indication, impaired renal function was the indication in 14 patients and need for undiversion in seven. Currently all but four are voiding satisfactorily or are on intermittent self-catheterisation, though six have significant stress incontinence. The clam procedure is easier, quicker and as satisfactory as substitution cystoplasty in selected cases.

Adolescent↗

Secreto-motor function of intestinal segments used in lower urinary tract reconstruction.

Mucus excretion, sialic acid excretion and secretory IgA (sIgA) production from patients with a substitution caecocystoplasty (20), augmentation "clam" ileocystoplasty (20) or ileal conduit (10) were measured. Significant amounts of all of these substances were present in the urine of reconstructed patients and showed no evidence of diminution with time. Motility was studied by videocystourethrography. In patients with a neuropathic aetiology the amplitude of contractions was significantly increased and produced incontinence. The results demonstrate that intestinal secreto-motor function in gut segments incorporated into the lower urinary tract continues normally and must be taken into account when considering the long-term management of these patients.

Colon↗

Videourodynamic assessment of diurnal urinary incontinence.

Persistent daytime incontinence is a fairly uncommon but important problem. Videourodynamic studies were carried out in 215 children presenting with this problem in whom there were no neurological signs and who had not responded to simple measures. Over 90% of symptomatic children were shown to have an abnormality, of which over half had detrusor instability and a fifth had the wide bladder neck anomaly. We consider that it is important that these children are fully assessed as many can be helped.

Adolescent↗