Computerized morphometric analysis of muscular structure in pelviureteric junction obstruction [PUJO] based on aetiology and duration of obstruction

ABSTRACT

The pathophysiology of pelviureteric junction obstruction [PUJO] is unknown. Abnormalities of smooth muscle and/or collagen fibers in PUJ were reported by light and electron microscopes. Computerized image analysis was used to objectively quantify the percentage of smooth muscle fibers in surgical specimens of PUJ obtained from 45 patients [28 male and 17 female], aged 1- 53 years mean age 27.48 +/- 12.27, after surgical repair using dismembered technique of pyeloplasty. Control materials were obtained from 10 patients [aged 40-70 years] in whom nephrectomy was done for other pathology than PUJO. Twenty different fields were examined for each tissue section, which were stained by Masson trichrome stain for smooth muscle fibers. In patients with PUJO the percentage of smooth Muscle fibers [SMFs] ranged between 16 and 44% with a mean 26.08 +/- 5.68 while in control group, the Percentage of SMFs was ranging between 41 and 89%with amean 64.22 +/- 13.13 In 34 patients with intrinsic PUJO the percentage of SMFs ranged from 15 to 49% with a mean 24.71 +/- 4.74 while in 11 patients with extrinsic PUJO it ranged between 15 and 49% with a mean 30.31 +/- 6.47. Out of 34 patients with intrinsic PUJO, in patients below I6 years [n=10] the percentage of SMF ranged between 17 and 44% with a mean 27.83 +/- 4.3 and while in patients above 16 years [n=24] the percentage of SMF ranged between 15 and 49% with a mean 23.41 +/- 4.33. The significant difference between mean percentage of smooth muscle fibers in PUJO group 26.08% and control group 64.22% indicate the role of SMF in pathogenesis of PUJO. The difference between percentage of SMF in intrinsic PUJO 24.71% and those of extrinsic causes 30.3 1%, confirm this finding. The difference in percentage of SMFs in patients with intrinsic PUJO below 16 years 27.83% and those above 16 years 23.41% indicate that the duration of obstruction may affect the muscular structure