ANORECTAL MANOMETRY IN CHILDREN WITH PHYSICAL HANDICAP

Abstract

In order to assess bowel function in children with physical handicap, 39 children with Spina Bifida (SB) and 25 children with Cerebral Palsy (CP) had anorectal manometry performed. Mean age was 11.3 years (range 3-22) and there were 34 m and 30 f. Twenty four enuretic children served as controls. Portable anorectal manometry equipment was used comprising a computer linked via pressure transducers to an anal probe with 3 waterfilled anal sensor balloons (b1,b2 and b3) and a terminal 200 ml air filled balloon. Resting pressure in the outermost balloon (b1) was lower in both patient groups than in controls (41.5 + 21.5 in SB and 43.6 + 15.4 in CP vs 52.3 + 18.4 mm Hg, p B and 36.0 ± 17.2 in CP vs. 35.7 ± 15.3 mm Hg). Mean anal resting pressure (average b1 and b2) was lower in patients than controls (37.6 ± 21.5 in SB and 39.8 ± 14.5 vs. 44 mm Hg). Anal rhythmical activity, generated by the internal sphincter, showed slower waves with large amplitudes in SB and CP compared to controls. An indirect assessment of rectal size can be gained by observing the change in anal pressures in the innermost balloon (b3) during maximal rectal distension. In b3 the pressure increased less in SB than controls but fell in CP (+2.6 ± 15.4 in SB and -2.2 ± 10.5 in CP vs. +9.2 ± 15.3 mm Hg, both p < 0.001). In SB the pressure in b1 fell as in controls whereas in CP the pressure fell less (-19.0 ± 17.8 in SB and -8.6 ± 18.4 in CP vs. -17.8 ± 11.1, p<0.001 for CP vs. controls). The pressure fall in b2 was equal in SB and controls but more pronounced in CP (-11.15 ± 19.7 in SB and -14.7 ± 16.9 in CP vs. -11.1 ± 18.9 mm Hg). Anal pressure is low in SB and CP. Internal sphincter pressure is normal but is dynamics are altered. Rectal size is increased but megarectum is not found. These findings explain why patients with CP tend to constipation whilst patients with SB are characterised by greater incontinence rather than constipation.