Modified ureteral orthotopic reimplantation method for managing infant primary obstructive megaureter: a preliminary study

Advancements in Surgical Management of Megaureters

PURPOSE OF REVIEW

To review and describe the recent evolution of surgery for the various types of pediatric megaureter.

RECENT FINDINGS

Megaureter management first relies on determining the underlying cause, whether by obstruction, reflux, or a combination, and then setting appropriate surgical indications because many cases do not require surgery as shown by observation studies. Endoscopic balloon dilation has been on the rise as a major treatment option for obstructive megaureter, while refluxing megaureters can also be treated by laparoscopic and robotic techniques, whether extravesically or transvesicoscopically. During ureteral reimplantation, tapering is sometimes necessary to address the enlarged ureter, but there are also considerations for not tapering or for tapering alternatives. Endoscopic and minimally invasive surgeries for megaureter have been the predominant focus of recent megaureter literature. These techniques still need collaborative prospective studies to better define which surgeries are best for patients needing megaureter interventions.

Surgical management of vesicoureteral junction obstruction (VUJO) in children: A comparative study between transvesicoscopic Cohen reimplantation and transumbilical laparoendoscopic single-site (TU-LESS) Lich-Gregoir techniques

BACKGROUND

There are many reports on the application of minimally invasive technology in the correction of children's VUJO, but there is no report on the treatment of children's VUJO by the TU-LESS Lich-Gregoir method. We aimed to comparatively analyze the therapeutic outcomes of transvesicoscopic ureteral reimplantation Cohen procedure (TUR-C) and TU-LESS surgery Lich-Gregoir procedure (TU-LESS-LG) in pediatric VUJO.

METHODS

The data of 49 children with VUJO admitted from January 2016 to January 2020 were retrospectively analyzed. Based on different surgical methods, they were divided into the TUR-C group (23 cases) and the TU-LESS-LG group (26 cases). The demographic characteristics, perioperative characteristics, postoperative complications, the recovery of renal function, and the improvement of hydronephrosis were compared between the two groups.

RESULTS

There were no statistical differences in demographic characteristics and preoperative data between the two groups. The TU-LESS-LG group was superior to the TUR-C in terms of average operation time and postoperative hospital stay. There was no statistical difference between the two groups in terms of postoperative complications, postoperative recovery of renal function, and improvement of hydronephrosis.

CONCLUSION

The two surgical methods can achieve a similar curative effect in the treatment of VUJO. The TU-LESS-LG has more advantages in operation time, postoperative hospital stays, the wider age selection range of cases, megaureter tapering, and cosmetic incision, but the operation is more difficult.

Ureteral tunnel length versus ureteral orifice configuration in the determination of ureterovesical junction competence: A computer simulation model

INTRODUCTION

The long-held belief that a ureteral re-implant tunnel should be five times the diameter of the ureter, as proposed by Paquin in 1959, ignores the effect of the orifice on the occurrence of reflux. In 1969, Lyon proposed that the shape of the ureteral orifice (UO) is more important than the intravesical tunnel. However, both theories missed quantitative evidence from principles of physics. The goal of the current study was to test Lyon's theory through numerical models (i.e. to quantify the sensitivity of ureterovesical junction (UVJ) competence to intravesical tunnel length and to the UO).

MATERIALS AND METHODS

The closure of a three-dimensional spatial configuration of ureter, constrained within a bladder, was simulated. Two common UO shapes (i.e. golf type vs 2-mm volcano type (Summary Fig.)), and two different intravesical ureteral tunnel length/diameter ratios (3:1 and 5:1) were examined. The required closure pressures were then compared.

RESULTS

The UO was a significant factor in determining closure pressure. Given the same intravesical ureteral tunnel length/diameter ratio, the required closure pressure for the volcanic orifice was 78% less than that for the golf orifice. On the other hand, the intravesical ureteral tunnel length/diameter ratio had minimal effect on the required closure pressure. As the intravesical ureteral tunnel length/diameter ratio changed from 3:1 to 5:1, the required closure pressure was reduced by less than 7%, regardless of the orifice shape.

CONCLUSIONS

The simulation results showed that UVJ competence was more sensitive to a 2-mm protrusion of the UO compared to an increase in the intravesical tunnel length from 3:1 to 5:1. This agrees with Lyon's theory, and at the same time challenges Paquin's 5:1 rule. Researchers could use this information to consider the UO configuration in further animal, human, computer or material models.