- Materials
14 experimental GuiZhou Minipigs (provided by Experimental Animal Center of Zunyi Medical College), male, 12-months-old, weight 21 ± 1.38 kg, were randomly numbered and divided into group A and group B by computer: Group A (n = 7) received the left Yang-Monti ileal ureter, the left ileal ureter and the left ureter end of the anastomosis; group B (n = 7) received left Yang-Monti ileal ureter, left ileal ureter and bladder anastomosis. The contralateral kidney was removed from both groups 1 week after surgery and two experimental animal models were established. The experiment was approved by the Medical Ethics Committee of GuiZhou Provincial People's Hospital. All the experimental procedures were conducted according to local guidelines on the ethical use of animals and the Guide for the Care and Use of Laboratory Animals (National Institutes of Health (NIH), Publication No 85–23, revised 2011). Refinement refers to the improvement of conditions, the treatment of animals, and the improvement of animal welfare on the basis of scientific principles: or the improvement of experimental procedures and improvement of experimental techniques to avoid or alleviate the pain and nervousness of animals that are not related to the purpose of the experiment scientific method.The sample size was calculated according to reference [17] and the formula was used. Although the sample size was small, it was found to be statistically significant.
- Surgical procedures and postoperative treatment
2.1 surgical steps
Group A surgical steps:
(1) Preparation before surgery: Animals were fasted for 24 hours and water for 12 hours before surgery.
(2) Anesthesia: After weighing, anesthetize with 3% pentobarbital sodium (Shanghai Xinya Pharmaceutical Co., Ltd.) 30 mg/kg intraperitoneal injection. Intravenous infusion of propofol (Sichuan Guorui Pharmaceutical Co., Ltd.) induced dose of 1-2mg/kg, maintained at 1-2mg/kg/h.
(3) Abdominal skin preparation, 2.5% iodophor disinfection, sterile surgical towel, take the left rectus abdominis incision, layer by layer to cut the skin, subcutaneous tissue, muscle, peritoneum.
(4) Free ureter: push the left side of the colon to the medial side, reveal the left posterior peritoneum, cut the left posterior peritoneum, look for the left ureter, from the distance of the renal pelvis about 2 cm from the lower to the middle segment, remove the middle and upper ureter, to create a model that replicates exactly the real extended ureteral injuries.
(5) Selection of intestinal segments: A section of 2-3 independent mesenteric blood supply intestines was taken from the ileocecal area 40 cm and the surrounding tissues were protected with gauze.
(6) Restoration of intestinal continuity: The two broken ends of the intestine were thoroughly washed with physiological saline, then fully disinfected with 2.5% iodophor, and the intestine was anastomosed with 5-0 non-absorbable suture. The whole layer was sutured first, and the muscle layer was sutured to restore the continuity of the intestine and close the mesangial hole.
(7) Cutting of the intestine: The cutting method of the intestine is referred to [17] (Fig. 1). The intestine segments were thoroughly cleaned and disinfected with saline and 2.5% iodophor, and the intestine segments were cut into three segments, each of which was 2 cm in length and with independent and intact mesenteric vessels (Fig. 2a). The cross section of the intestine was taken from the mesentery at 6 o'clock. The three segments of the intestine were cut longitudinally at 9, 12, and 3, respectively, to form a three-section rectangular intestine (length 4-6 cm, width 1.5 cm) (Fig. 2b) ). The adjacent intestine pieces were sequentially sutured with an antibacterial micro-chord line (4-0) to form a rectangular intestine piece having a length of about 12-18 cm and a width of 2 cm (Fig. 2c). The intestine piece was wrapped around a 30 cm long F12 silica ureteral stent tube, and the intestine piece was sutured longitudinally with a 5-0 absorbable suture (Johnson) to form a long tubular structure to form a ureter replacement segment (Fig. 2d).
(8) Reconstruction of the ureter and ureter stump anastomosis: one end of the ureteral stent has been placed in the renal pelvis and the other end of the ureteral stent has been inserted into the bladder through the naive ureteral stump, the top of the bladder is cut open, the stent tube is pulled out and the bladder is made, suture the bladder incision as a stent and drainage. The reconstructed ureteral upper end was anastomosed to the ureteral stump with a 5-0 absorbable suture. The lower end was anastomosed to the remaining ureteral lower end. The anastomosis was performed with a full-thickness suture and sutured for approximately 6-8 needles (Fig. 2e).
(9) The distal end of the ureteral stent tube was placed under the skin of the left lower abdomen, and the incision was closed layer by layer.
Group B surgical steps:
(1) - (7), (9) same surgical procedure as group A.
(8) The reconstructed ureter and the bladder stump are anastomosed: one end of the ureteral stent tube is placed in the renal pelvis, the other end is placed in the bladder on the left side of the bladder, and the top of the bladder is cut open, the stent tube is pulled out and the bladder is made, and the suture is sutured. Bladder incision, as a stent and drainage. The reconstructed ureteral upper end was anastomosed to the ureteral stump with a 5-0 absorbable suture. The lower end was directly anastomosed to the bladder. The anastomosis was performed with a full-thickness suture and sutured for about 8-10 needles (Fig. 2f).
The contralateral kidney and ureter were removed in the two groups one week after surgery.
2.2 post-operative treatment:
Fasting for 24 hours after operation, liquid diet on the second day after surgery, normal feeding after 3-5 days, daily intramuscular injection of penicillin (1.5ml/kg), and metronidazole injection 50ml/day for total 5 days. The ureteral stent tube was indwelled for 4 weeks and then surgically removed and removed subcutaneously. When collecting tissues and organs for examination, abdominal anesthesia was performed first. After the completion of the collection, chemical euthanasia was used to terminate the life of the animals from intravenous high-dose anesthetics(3% pentobarbital sodium,100 mg/Kg).
- Observation indicators and data collection:
All the experimental animals in the two groups were examined for the following items after surgery:
(1) Operation time and length of surgical incision: The operation time and length of the surgical incision were compared between the two groups.
(2) Determination of blood and kidney function: Blood samples were taken to detect changes in serum creatinine and urea nitrogen before surgery, and 2 weeks, 6 weeks and 12 weeks after surgery.
(3) Intravenous pyelography (IVU) and cystography: intravenous pyelography (IVU) and cystography were performed 12 weeks after surgery to observe the ureteral patency and vesicoureteral reflux.
(4) Urine bacteriological determination: urine was collected from the bladder in the urine at 12 months after surgery to see if there was a urinary tract infection.
(5) Gross visual observation and histological examination: Gross macroscopic observation and histological examination of the intestine ureter were performed after 12 months of operation to understand the pathological changes of the anastomosis and intestinal ureter.
- Statistical analysis:
Animal grouping was designed according to the principles of equilibrium, control and repetition. All measurement data were expressed as mean ± standard deviation. The t test was used for comparison between the two groups. The test level: p was 0.05, and the difference was statistically significant at p < 0.05. Statistical analysis was performed using the SPSS 24.O software package.