ABSTRACT
Objective To investigate the relationship between preoperative renal cortical thickness and glomerular filtration rate (GFR) before and after minimally invasive surgery in patients with unilateral upper urinary tract obstruction. Methods 63 patients with upper urinary tract obstruction from July 2015 to June 2016 were enrolled in the study, including 34 males and 29 females, age ranged from 22 to 73 years old (52.21 ± 11.56). Their operation methods included 24 cases of ureteroscopic lithotripsy and lithotomy, 21 cases with one-stage percutaneous nephrostomy + two-stage percutaneous nephrolithotomy (PCNL), 18 cases of PCNL. The abdominal enhanced CT and single photon emission computed tomography (SPECT) were measured to RCT and GFR. Then all cases were divided into group A (moderate renal impairment, 15.0 ml/min ≤ GFR < 30 ml/min), group B (severe renal damage, 7.5 ml/min ≤ GFR <15.0 ml/min) and group C (extremely severe renal injury, GFR < 7.5 ml/min) according to preoperative renal GFR, and changes of GFR before and after surgery were compared among three groups. Simple linear correlation analysis was used to analyze the correlation between preoperative RCT and other indexes in group A and B. Results 9 patients were not measured RCT because of serious hydronephrosis, 54 patients included 20 cases of RCT >10 mm, 23 cases of 5 ～ 7 mm and 11 cases of <5 mm, and the average value was (10.75 ± 4.91) mm. The preoperative RCT in group A was significantly higher than that in group B (P < 0.05). GFR at 1 and 9 months after operation in three groups were significantly higher than that before operation in the same group (P < 0.05). GFR at 1 and 9 months after operation in group A were significantly higher than that the other two groups, and GFR at 9 months after operation in group B was significantly higher than that in group C (P < 0.05), but there were no significant differences in GFR at 1 month after operation between group B and C (P > 0.05). GFR recovery value at 1 month after operation in group B was significantly lower than that in other two groups (P < 0.05), but there were no significant differences in GFR at 9 months after operation among three groups (P > 0.05). Preoperative RCT was positively correlated with preoperative GFR (r = 0.613), GFR at 1 month after operation (r = 0.697) and the recovery value (r = 0.552), GFR at 9 months after operation ((r = 0.589) and recovery values (r = 0.488), and the differences were statistically significant (P < 0.05). Conclusion Removal of upper urinary tract obstruction could recover the renal function to varying degrees, even for patients with extremely severe renal injury, who could retrieve their kidney. Preoperative RCT could be helpful in judging the renal function during operation, especially for the postoperative recovery of renal function.