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Biomedical subjects

N G Kock

Publications and source records attributed to N G Kock.

At least 37 records · Page 2Linked to original sources
PubMed1989

Replacement of the bladder by the urethral Kock pouch: functional results, urodynamics and radiological features.

After cystoprostatectomy for cancer of the bladder 43 men were provided with a detubularized, low pressure ileal reservoir (Kock pouch) connected to the urethra. Reflux was prevented by an intussusception valve. There was no operative mortality and few early complications. At followup the mean postoperative observation time was 13 months, with a range of 5 to 20 months. Late complications included manifestations of local tumor recurrence or distant metastases in 9 patients within 6 months postoperatively, which made adequate functional evaluation impossible. In 18 patients reflux to the upper urinary tract due to eversion or sliding of the antireflux valve occurred at various postoperative intervals. In 16 of these patients incontinence developed as a consequence of the reflux. Surgical correction of the failing antireflux valve restored reflux prevention and continence. Within 3 to 6 months the capacity of the reservoirs had reached an ultimate volume of approximately 600 ml. Pressure waves exceeding 40 cm. water seldom occurred in the mature reservoirs and then only at high filling volumes. The mean urethral resting resistance to flow was 64 cm. water. The configuration and function of the upper urinary tract improved or stabilized postoperatively. Of 34 evaluable patients 30 were continent during the day with a voiding frequency of 3 to 5 times and dry at night with a frequency of 0 to 2.

Adult↗
PubMed1989

Voiding pattern, urinary volume, composition and bacterial contamination in patients with urinary diversion via a continent ileal reservoir.

A series of 41 patients with a continent ileal reservoir for urinary diversion (Kock pouch) was studied with regard to voiding pattern (voiding frequency), voided volume, urinary composition, bacterial contamination and mucus secretion. The mean voiding frequency in 21 patients was 5/24 h and the time required for the procedure, including the time to cover the stoma with a bandage, was 3 to 5 min; 2 patients voided once or twice at night, while 19 patients never did so. The mean volume voided during the day were significantly smaller than the volume voided in the morning. The total 24-h urinary volume exceeded that of normal individuals but the 24-h secretion of electrolytes was within normal limits. Bacterial contamination was found in most samples of urine. Evacuation was not impeded by the rich mucus content of the urine and mucus production did not diminish with time.

Adult↗
PubMed1988

Absorption of L-phenylalanine in human ileal reservoirs exposed to urine.

The mucosa of ileal reservoirs exposed to urine undergoes successive structural changes, indicating a loss of absorptive capacity. In patients with urinary diversion via a continent ileal reservoir, the active absorption of L-phenylalanine from the reservoir was studied at different postoperative time intervals. A test solution containing L-phenylalanine was instilled into the reservoir and samples were taken at intervals during a period of one hour for determination of phenylalanine. In one group of patients, urine from the kidneys by-passed the reservoir via a catheter inserted into the afferent segment. Within three months after construction of the ileal reservoir, the uptake was significantly slower than that in ileostomy reservoirs and the absorption decreased even more with longer observation times. Mixing of urine with the reservoir contents did not influence the uptake of L-phenylalanine to any significant degree. The reduced absorption of L-phenylalanine indicates that the uptake of other substances from this type of ileal reservoirs might be decreased also.

Absorption↗
PubMed1988

Quality of life in ileostomy patients before and after conversion to the continent ileostomy.

In a prospective study the quality of life was evaluated in 31 consecutive patients before and after conversion from a conventional to a continent ileostomy. Patient expectations, immediate emotional reactions after the operation and attitudes at the time of the interview were more positive towards the continent ileostomy than the conventional ileostomy. An improved working capacity was affirmed after conversion to the continent ileostomy. Leisure activities and the quality of sexual life were most positively influenced by the continent ileostomy, whereas established family and social relations were not considerably influenced by either type of ileostomy. In conclusion the continent ileostomy improves the quality of life in patients requesting conversion from a conventional ileostomy.

Adaptation, Psychological↗
PubMed1988

Urinary diversion to the augmented and valved rectum: preliminary results with a novel surgical procedure.

A new method for urinary diversion to the rectum was elaborated in animal experiments and currently has been used in 19 patients. Reflux of the rectal content to the colon and to the upper urinary tract is prevented by the fashioning of an intussusception valve at the rectosigmoid junction. The rectum is augmented by anastomosing an ileal patch to the anterior rectal wall. A transverse colostomy protects the construction for 6 to 8 weeks. Of the 19 patients 3 had local recurrence or metastasis within 6 months. Thus, 16 patients with a followup of 3 to 14 months are evaluable. All patients are continent during the daytime with an emptying frequency of 3 to 5 times and dry at night with a frequency of 0 to 2. In 3 patients partial sliding of the sigmoid intussusception valve occurred causing reflux of rectal contents to the sigmoid and to the right ureter in 1. Reflux to the upper urinary tract has not been revealed in any of the other patients. With 1 exception excretory urography has demonstrated either improvement or stabilization of the upper urinary tract post-operatively. The rectal capacity increased from 200 to 700 ml. after 6 months. With the reservoir full the mean basal pressure was 17 cm. water and the mean maximum pressure was 24 cm. water.

Adult↗
PubMed1988

Urinary diversion to the augmented and valved rectum. An experimental study in dogs.

A new model for diverting urine to the rectum was tried in dogs. An intussusception valve was constructed at the junction of the sigmoid colon and the rectum allowing passage only in aboral direction. The rectum was augmented by patching it with an opened and folded ileal segment. The ureters were implanted into the rectum by a new anti-reflux method. All three dogs survived the operation. The volume of the augmented rectum increased from 80-150 ml at operation to a maximum of 750 ml six months after the operation. The pressure in the rectum did not exceed 18 cm of water during maximal filling. No reflux to the bowel proximal to the intussusception valve or to the ureters could be observed even during maximal filling of the augmented rectum. No signs of obstruction of the fecal stream by the intussusception valve were seen. In three out of five implanted renal units strictures developed at the implantation sites and resulted in impaired renal function. In the two renal units without strictures, no impairment of kidney function was found. Involuntary leak from the anus was not observed and no masceration was found around the anus. These experiments are regarded as very encouraging an a clinical trial is now under way.

Animals↗
PubMed1988

Pregnancy and delivery in patients with a continent ileostomy.

Patients undergoing surgical treatment for inflammatory disease of the intestine are often in their reproductive years. Therefore, it is highly relevant to study the influence of surgical treatment on later pregnancy and delivery. Reported herein are 28 patients with continent ileostomies who have carried 37 pregnancies to term. An increased urge to empty the ileostomy reservoir, especially in the late period of pregnancy, was noted by the majority of patients. About one-third of the patients reported some difficulties with intubation of the reservoir in late pregnancy but in only a few patients did these disturbances result in a revisional operation after delivery. Pregnancy was normal in most instances and only four premature childbirths occurred. All pregnancies resulted in live birth. Vaginal delivery was successful in the majority of the patients, cesarean section being chosen for obstetric reasons in nine instances. From this study, it is concluded that, in patients with a continent ileostomy, normal pregnancy and delivery can be expected. However, in a few instances, the ileostomy function may be disturbed, necessitating later revisional operations.

Adolescent↗
PubMed1987

An appliance-free, sphincter-controlled bladder substitute: the urethral Kock pouch.

A modified Kock pouch was constructed in 16 patients with cancer of the bladder in whom cystoprostatectomy was indicated. Surgery entailed creation of a Kock pouch with 1 valve for prevention of reflux. The pouch then was anastomosed to the urethral stump. There was no operative mortality. Followup ranged between 3 and 9 months. Excretory urograms revealed excellent upper tract function and good evacuation of the pouch with minimal residual urine. Urodynamic studies demonstrated a volume capacity of greater than 300 ml., with pressures of less than 40 cm. water. All patients were continent during the day. Nocturnal enuresis was observed in 4 patients, 3 of whom responded favorably to I-desamino-8-D-arginine vasopressin therapy. The procedure is suitable whenever the urethra can be preserved after cystectomy for cancer.

Adult↗
PubMed1987

Volume capacity and pressure characteristics of the continent ileal reservoir used for urinary diversion.

The volume capacity and the pressure characteristics of the continent ileal reservoir for urinary diversion were studied at specific intervals postoperatively in 26 patients. The reservoir volume increased during the first year postoperatively from approximately 100 ml. at operation to a mean of 735 ml. and then remained stable during an observation period of up to 7 years. The basal pressure increased during filling from 0 to about 10 cm. water. During physiological conditions, that is when the reservoir was filled by diuresis, the basal pressure was equal to those pressures measured during saline infusion at corresponding reservoir volumes. Calculation of the magnitude of motor activity by 2 different methods showed a significant decrease in activity at 12 months compared to at 2 months after construction of the reservoir. Data from the continent urostomy reservoir were compared to corresponding data from the continent ileostomy and cecal reservoirs for fecal diversion, these being obtained in previous studies in our laboratory. The ileal reservoirs used for fecal or urinary diversion were practically identical with regard to volume capacity, basal pressure and motor activity. However, the cecal reservoir had a significantly lower volume capacity and higher basal pressure at corresponding reservoir volumes, while the motor activity was approximately 10 times greater than in the ileal reservoir. The results indicate that with regard to volume capacity and pressure characteristics the ileal reservoir is superior to the cecal reservoir as a receptacle for urine.

Adult↗
PubMed1987

Expansion of various types of ileal reservoirs in situ. An experimental study in rats.

In experiments on rats four types of ileal reservoirs were constructed and left to expand in situ. After 3 months the volumes and tissue weights of the various reservoirs were compared. The reservoir types were: two loops, isoperistaltic (type I), two loops, antiperistaltic (type II), three loops, S-shaped (type III) and "four loops', double-folded U loop (Kock pouch) (type IV). There was a considerable volume increase in all types of reservoir as well as a marked increase in their tissue weight. The expansion of the reservoirs in groups III and IV was significantly greater than that in groups I and II. The difference in expansion could possibly be explained by the greater radius in three- and four-loop reservoirs compared with two-loop reservoirs if Laplace's law is applied to this process. According to this law the tension in the wall of a tube increases with increasing radius.

Anal Canal↗
PubMed1987

Drainage of the upper urinary tract as recorded with renography in patients with a continent urostomy (Kock pouch). An experimental study with various degrees of reservoir filling.

The drainage from the upper urinary tract was studied by the use of renography in thirteen patients with well functioning continent ileal reservoirs for urinary diversion (Kock-pouch). Renography was performed with empty reservoir and with submaximal or maximal filling of the reservoir. The reservoir pressure was continuously recorded when renography was performed with a full reservoir. When the reservoir was empty renography showed normal drainage in all patients. When the reservoir was full the renography was normal in eight patients, these having a mean reservoir volume of 715 ml but showed a delay in five patients, these having a mean reservoir volume of 930 ml. When the renography was repeated in the latter group of patients with submaximal filling (mean reservoir volume 544 ml) there was no delay of the drainage phases on the renograms. In these five patients the considerable "over-filling" of the reservoir had resulted in volumes greatly exceeding the previously recorded maximal reservoir capacity and also in pressures exceeding considerably those usually recorded in ileal reservoirs. These results show that the pressure in the bladder substitute is of great significance for the drainage from the upper urinary tract and that the low pressure ileal reservoir under ordinary circumstances does not obstruct the flow from the upper urinary tract.

Adult↗
PubMed1986

Morphologic changes in ileal reservoir mucosa after long-term exposure to urine. A study in patients with continent urostomy (Kock pouch).

In patients with supravesical urinary diversion, continent ileal reservoirs utilized for urinary collection were examined by endoscopy at intervals of 1 month to 9 years after surgical construction, and biopsy specimens were obtained for light microscopy and morphometry. The gross appearance of the mucosa showed alterations in the shape of the shorter and broader finger-like villi during the first postoperative month to the subsequent very low ridges and convolutions or, in some instances, flat mucosa devoid of individual villi. Starting between 1 and 3 years after the surgical construction, endoscopically smooth areas were encountered in caudal areas of the reservoir, and the areas were mixed with islands of villous mucosa. Microscopically and morphometrically, the specimens from villous areas confirmed reduction in villous height and increase in crypt depth, whereas no changes were seen in the epithelial mitotic frequency. The number of mucus-storing goblet cells increased already within 1 month after construction. Specimens obtained from smooth areas showed alterations in the intestinal structure, with reduction of crypts, decreased height of epithelial cells, and occasional epithelial denudation. No signs of fibrosis, foreign-body reaction, or dysplasia were encountered. The constant exposure to urine leads to adaptive changes of the reservoir mucosa, resulting in a true atrophy of villi, crypts, and individual epithelial cells.

Adult↗
PubMed1986

Ultrastructural and histochemical changes in ileal reservoir mucosa after long-term exposure to urine. A study in patients with continent urostomy (Kock pouch).

Mucosal biopsy specimens were obtained from ileal reservoirs used for urinary collection in patients with continent urostomy. Shortly after construction of the reservoir there was a reduction in villous height and an increase in crypt depth. After 2 to 3 years of observation, avillous areas were noted in the reservoir mucosa, mixed with islets of villous mucosa. Specimens from the avillous areas showed a marked decrease in height of superficially located enterocytes, with loss of microvilli and a reduction in cell organelles. The histochemically demonstrable activity of oxidative enzymes was significantly reduced in the epithelial cells. There was an increase in the number of goblet cells and autonomic nerve fibres in the crypt layer. The constant exposure to urine led to significant alterations of the ileal mucosa resulting in avillous areas mixed with villous remnants in which many of the intestinal characteristics both structurally and functionally disappear.

Adult↗
PubMed1986

Volume capacity and pressure characteristics of the continent cecal reservoir.

In 11 patients with continent cecostomy, the volume capacity and pressure characteristics of the cecal reservoir were studied at several intervals postoperatively. The reservoir volume stabilized at 400 milliliters four months postoperatively. The basal pressure increased during filling to approximately 9 centimeters of H2O. Pressure waves appeared at all filling volumes in the reservoir but increased in frequency and amplitude with increasing volume. The area underneath the pressure waves was calculated and used as a quantitative measurement of the motor activity. In this manner, a significant increase in motor activity was seen with increasing reservoir volume, although no significant change of motor activity was seen with increasing time after operation. Data from the cecal reservoir were compared with corresponding data from the ileal reservoir obtained in a previous study at our laboratory. This comparison showed a smaller volume capacity and higher basal pressure in the cecal reservoir at identical filling volumes. The motor activity in the cecal reservoir was 20 times greater than that in the ileal reservoir. Thus, the cecal reservoir has a low adaptability to distension compared with the ileal reservoir.

Adolescent↗