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Biomedical subjects

S Akervall

Publications and source records attributed to S Akervall.

8 recordsLinked to original sources

Pouch size: the important functional determinant after restorative proctocolectomy.

Sixty-seven patients with a J-shaped ileonanal pouch were studied over a 2-year period with regular recording of sphincter and pouch characteristics and analysis of their role in functional outcome. Although there was a 27 per cent permanent reduction in resting anal pressure (RAP) (P less than 0.001), two-thirds of the patients still had a RAP within the normal range. The mean(s.d.) pouch volume increased during the first year from 132(46) ml to 282(85) ml. RAP was not related to functional outcome and preoperative RAP was not predictive of subsequent function. Large pouch volume and compliance correlated with low defaecation frequency (range of r = 0.27-0.36; P less than 0.05) and good overall function (r = 0.37-0.56; P less than 0.01). The initial pouch volume was predictive of subsequent overall function. The ileal length used for pouch construction predicted subsequent pouch volume (r = 0.48; P less than 0.001) and to some extent functional outcome (r = 0.28-0.37; P less than 0.05). However, the studied variables accounted for only 21 per cent of the total variance of functional outcome.

Adolescent↗

Manovolumetric and sensory characteristics of the ileoanal J pouch compared with healthy rectum.

Pouch volume, motility, sensory function and integrated pouch-anal mechanisms during graded isobaric distension of the pouch were prospectively studied in 67 patients with a J pouch-anal anastomosis. The findings were related to functional outcome. Thirty-six normal controls were studied for comparison. In contrast with normal rectum, the ileal pouch exhibited pronounced motility, and pouch contractions were frequent even at a high distension pressure. The presence of high pressure motility was associated with a poor functional outcome. The threshold pressure and threshold volume for eliciting first sensation of filling and urge to defaecate were significantly higher in the ileal pouch. The pressure threshold levels were not related to the functional outcome. Sphincter inhibition on pouch distension reappeared in 25 per cent of the patients. The distension pressure required to elicit the inhibition was considerably higher than in the control subjects. The functional result was similar irrespective of whether sphincter inhibition was present or not. The motor and sensory function of this artificial setting appear to be controlled by nervous mechanisms that are different from those in the healthy anorectum.

Adenomatous Polyposis Coli↗

The effects of age, gender, and parity on rectoanal functions in adults.

The effects of age, gender, and parity on rectoanal function were examined in a cross-sectional population study, including 68 normal subjects (32 men and 36 women) aged 23 to 91 years. Rectal volumetry was evaluated with graded isobaric rectal distension with 5-60 cm H2O in combination with anal manometry. Data were analysed by use of the multiple regression technique. Increasing age correlated with a decrease in rectal volume (r = -0.285, p less than 0.05), resting anal pressure (r = -0.625, p less than 0.001), and maximal squeezing pressure (r = -0.557, p less than 0.001). The decrease in maximal squeeze pressure with age was similar in men and women (approximately = 1% x year-1), although the median of maximal squeeze pressure in women was 58.3-75.7% of that in men (p less than 0.001). Nor was there a difference in resting anal pressure between men and women. An age-dependent increase was observed for the pressure threshold to produce an initial sensation of rectal filling and the rectoanal inhibition reflex (r = 0.446, p less than 0.001). The sensory threshold increased with age, but this was more pronounced in women. No effect of parity on rectoanal function could be demonstrated. However, this would best be investigated in a longitudinal population study. We believe that identification of causes for interindividual variation and regression analysis procedures will increase the discriminative accuracy of analysis of rectoanal function. The present study shows that several of the demonstrated age-related changes have a tendency to expose elderly subjects, particularly women, to the problems of incontinence.

Adult↗

Rectal reservoir and sensory function studied by graded isobaric distension in normal man.

The rectal expansion and concomitant sensory function on graded, isobaric, rectal distension within the interval 5-60 cm H2O was investigated in 36 healthy young volunteers. Anal pressure and electromyography (EMG) from the external anal sphincter were simultaneously recorded. Rectal distension caused an initial rapid expansion followed by transient, often repeated, reflex rectal contractions and a slow gradual increase of rectal volume. The maximal volume displaced by the first reflex rectal contraction was 18 (13) ml, which was less than 10% of the volume at 60 s. The pressure threshold for appreciation of rectal filling was 12 cm H2O (95% CL 5-15 cm H2O) and coincided with the threshold for rectoanal inhibition. Urge to defecate was experienced at 28 cm H2O (15-50 cm H2O) distension pressure, which was close to the threshold for maximal rectal contraction, also coinciding with the appearance of the external anal sphincter reflex. The interindividual variation of rectal volume on distension with defined pressures varied widely, indicating a considerable variation of rectal compliance in normal man. No correlation was found between rectal volume and sex or anthropometric variables. The relative variations in pressure thresholds for eliciting rectal sensation and rectoanal reflexes were less than the corresponding threshold volumes. It was concluded that the dynamic rectal response to distension reflects a well graded reflex adjustment ideal for a reservoir.

Adult↗

The functional results after colectomy and ileorectal anastomosis for severe constipation (Arbuthnot Lane's disease) as related to rectal sensory function.

Rectoanal manovolumetry during graded isobaric rectal distension was carried out in 12 women with severe constipation classified as slow transit constipation (Arbuthnot Lane's disease). The resting anal sphincter pressure, the rectoanal inhibitory reflex and the rectal capacity were all normal. While the distension volumes required to elicit sensation of rectal filling and an urge to defaecate were within normal limits in all patients the distension pressures required to elicit such sensations fell outside the 95% limits of variation of control subjects in 4 patients. All patients were subsequently subjected to colectomy and ileorectal anastomosis. Patients with normal rectal sensory function had a satisfactory functional result after colectomy, whereas the four patients with blunted sensation did not improve. These findings suggest that rectoanal manovolumetry with determination of the distension pressures required to elicit rectal sensation is an important preoperative measure to be used in patients with severe constipation for selection of patients suitable for colectomy and ileorectal anastomosis.

Adult↗

Does balloon dilatation and anal sphincter training improve ileoanal-pouch function?

Although patients' satisfaction may be high after restorative proctocolectomy the functional results are still far from perfect. Increased bowel frequency and imperfection in continence are common. Pouch volume and anal sphincter status are important determinants for the outcome. The aim of the present study was to evaluate if balloon dilatation of the pouch and sphincter biofeedback training might improve the results. Forty patients with an ileo-pouch anal anastomosis were randomized into a control and a treatment group. During the interval with a diverting ileostomy, patients in the latter group were subjected to balloon dilatation of the pouch and sphincter biofeedback training by using a manovolumetric technique. All patients were functionally assessed and anorectal manovolumetry performed preoperatively and at regular intervals postoperatively. Follow-up time was at least 12 months. Immediately before ileostomy take down patients in the treatment group showed a significant initial increase in pouch compliance compared with controls. However, a rapid and pronounced increase in pouch volume occurring after ileostomy closure in the control group equalized this initial difference. Anal resting tone and maximum squeezing capacity were at all intervals similar in the two groups. Bowel frequency per 24 h was similar and mucus soiling occurred to a similar extent in both groups, and the overall functional result as assessed according to a scoring system was equal at each interval. Balloon dilatation of the pouch and sphincter exercises appear not to be essential measures in these patients.

Adolescent↗

Manovolumetry: a new method for investigation of anorectal function.

A new technique for manovolumetric investigation of rectoanal function allowing for simultaneous recording of rectal volume, anal pressure and external sphincter EMG in response to graded rectal distension was developed. Distension pressure was generated by a water column between two reservoirs. Volume was recorded as shifts of water between the reservoirs. Anal pressure was recorded with a cylindrical balloon and electromyographic activity of the external sphincter by means of a needle electrode. It could be shown that although reduction of preset pressure was minimal, this factor had to be taken into account when rectal compliance is high. The position of the patients during the investigation has to be defined, because rectal volume changed with body position. Pull through studies of anal pressure indicated low sensitivity to displacement of the cylindrical anal probe. A pressure adaptation to the anal probe during eight minutes was noted. Representative recordings of the anorectal response to different isobaric pressures are presented. The present system offers new possibilities for investigation of rectoanal physiology in man.

Adult↗