[Process of recovery of peristaltic function at anastomotic stoma after dismembering pyeloplasty in rabbits].
OBJECTIVE
To study the process of recovery of peristaltic function at anastomotic stoma after dismembering pyeloplasty in rabbits.


METHODS
An animal model of obstructive hydronephrosis was made with 32 New Zealand rabbits. These rabbits were divided into four groups to be examined within the first, second, third, and fourth week respectively after a dismembering pyeloplasty was performed on them, eight rabbits in each group. Thirty-two normal New Zealand rabbits were divided into four corresponding control groups as controls. Pressures of the renal pelvis and upper ureter were measured, electromyogram was recorded, and histological examination was made to the tissue of anastomotic stoma before and after the operation.


RESULTS
In the normal control rabbits, the resting pressure was (10.8 +/- 1.3) mm Hg, contraction amplitude was (1.6 +/- 0.4) mm Hg, pulse amplitude of EMG was (0.39 +/- 0.10) mV, and pulse frequency was (5.4 +/- 1.0)/min in the renal pelvis; and the resting pressure was (11.7 +/- 1.7) mm Hg, contraction amplitude was (1.8 +/- 0.5) mm Hg, pulse amplitude of EMG was (0.38 +/- 0.08) mV, pulse frequency was (5.3 +/- 0.9)/min in the upper ureter. Within the first week after operation, the resting pressure of renal pelvis was (14.4 +/- 1.3) mm Hg, significant higher than normal (P < 0.05), the contraction amplitude of renal pelvis was (1.1 +/- 0.4) mm Hg, lower than normal (P < 0.05); the pulse amplitudes of EMG in renal pelvis (0.19 +/- 0.05) mV and in upper ureter (0.26 +/- 0.04) mV were lower than normal (P < 0.05). A thin layer of mucosa was seen covering the anastomotic stoma. In the second week after operation, no statistical difference was observed in resting pressure, contraction amplitude, amplitude of EMG, and frequency of EMG in renal pelvis between the experimental rabbits and the controls (P > 0.05). Newborn smooth muscle cells were seen running through the anastomotic stoma, and close contact was observed among the cells. Within the third week after operation, the pressures and EMG in renal pelvis and in upper ureter were not significantly different from those in normal rabbits (P > 0.05). Nerve endings could be seen near the anastomotic stoma. Within the fourth week after operation, newborn muscle cells became mature and arranged regularly, and contacted each other closely.


CONCLUSIONS
Within the first week after the dismembering pyeloplasty, no peristalsis runs through the anastomotic stoma, and the renal pelvic resting pressure increases. Within the second week after the operation, the newborn smooth muscle cells at the anastomotic stoma begin to exercise their contractive and conductive functions. Peristalsis begins to run through the anastomotic stoma. Within the third after the operation, the peristaltic function basically recovers to normal.
Mo
J
J
Department of Pediatric Surgery, First Hospital Affiliated to Sun Yat-sen University of Medical Sciences, Guangzhou 510089, China.
Wang
X
X
D000714:Anastomosis, Surgical / Q000379:methods; D000818:Animals; D004576:Electromyography / Q000379:methods; D005260:Female; D006869:Hydronephrosis / Q000601:surgery*; D007682:Kidney Pelvis / Q000601:surgery*; D008297:Male; D023421:Models, Animal; D009119:Muscle Contraction / Q000502:physiology*; D009130:Muscle, Smooth / Q000166:cytology / Q000254:growth & development / Q000502:physiology; D011817:Rabbits; D020127:Recovery of Function / Q000502:physiology*