EVALUATION OF SACRAL RATIO AS A PROGNOSTIC FACTOR IN PATIENTS WITH ANORECTAL MALFORMATIONS

Correlation between sacral ratio and bowel function as well as fecal continence has been well documented in patients with anorectal malformations (ARMs). One hundred and twenty children with ARMs were investigated in this study. Sacral ratio (SR) was measured from pelvic X-rays of patients. Among these, 52 patients (43%) had no pelvic X-ray and were excluded from this study. SR was measured by drawing three horizontal lines, through iliac crests (A), tip of coccyx (B) and inferior point of sacroiliac joints (C). The SR was determined by dividing the distance between lines B and C to the distance between lines A and B. In the normal and well developed children, the average ratio is ≥0.74. The SR was higher than 0.70 in 12 (17.7%) children and less than 0.69 in 56 children (82.3%). Among children with ARMs and abnormal SR, 38 cases (68%) had SR of 0.50-0.69; 12 cases (21.5%)had SR of 0.40-0.49 and 6 cases (10.5%) had SR of 0-0.39. In children with ARMs and normal SR, the fecal incontinence was observed in 2 cases (16%). In contrast, 16 cases (29%) with ARMs and abnormal SR had functional disturbance, either fecal incontinence or soiling (P < 0.12). When the patients had an absent sacrum, they had zero possibility for bowel control and frequently had major urinary problems. The sacral feature and SR appear to have a direct influence on the final functional outcome in ARMs. The abnormal SR < 0.7 correlates with poor bowel function. In patients with ARMs, sacral segment and SR are important factors in post operative bowel function disturbance.