Antegrade Stent Placement during Infant Laparoscopic Pyeloplasty: Our Technique and Surgical Video

INTRODUCTION

Early diagnosis of pelviureteric junction issues is increasingly common, leading to more laparoscopic pyeloplasty procedures in infants. Surgeons often use antegrade stent placement with small, soft double-J (DJ) stents (typically 3 or 3.5 size) due to the narrow ureters. Inserting these stents without a guidewire is challenging; even with a guidewire, it is difficult as the soft tip of the guidewire with the stent bends, making entry at the upper end difficult. Hence, the stiff end of the guidewire is used for easier entry, but can complicate navigation at the vesicoureteral junction. This article describes a straightforward method using a pusher as a sheath for the soft end of the guidewire, simplifying stent placement.

TECHNIQUE

Transperitoneal laparoscopic pyeloplasty was performed under general anesthesia. A hitch stitch was applied, followed by dismemberment and lateral spatulation of the ureter. The posterior layer of suturing was completed. A 14-gauge intravenous (IV) cannula was inserted along the line of the ureter, and the stylet was removed. The pusher, with the soft, curved end of the 0.018-sized guidewire, was directed toward the pelviureteric junction and carefully guided into the ureter. The soft, curved end of the guidewire was advanced into the bladder, easily passing through the vesicoureteral junction. The pusher was then withdrawn, leaving the guidewire in place. The 3 or 3.5 Fr DJ stent was positioned over the guidewire and advanced into the bladder using a pusher. Subsequently, the guidewire, pusher, and IV cannula were removed, and the upper end of the stent was placed in the renal pelvis. Stent placement in the bladder was confirmed by cystoscopy or visual confirmation during laparoscopy [Figure 1a-f]. The remaining steps of the pyeloplasty, including anterior wall suturing, were completed.

Figure 1.

(a) 14-Gauge intravenous cannula with stent pusher. (b) Pusher with soft end of 0.018 guidewire inside the pelviureteric junction. (c) Pusher removed after guidewire insertion. (d) Guidewire seen inside the bladder in a laparoscopic view. (e) 3Fr double-J stent placed. (f) Guidewire removed and the upper end placed in the pelvis

This technique was utilized in 20 infants with an average weight of 6.1 kg and age of 4 months (2–8 months), achieving a successful outcome in all cases. The average time taken for stent placement (from cannula insertion to upper end placement in the pelvis) was 5.30 min.

DISCUSSION

A stent during laparoscopic pyeloplasty can be placed through either retrograde or antegrade routes. Retrograde stent placement and its variations generally have higher success rates compared to the antegrade approach.[1] However, retrograde placement has the disadvantage of increasing surgical time because it requires repositioning the patient. It also decompresses the renal pelvis, making it harder to identify the pelvis and pelviureteric junction if the stent is inserted before pyeloplasty. In addition, it complicates spatulation and suturing.[2] If a retrograde stent is placed after pyeloplasty, there is a risk that it may protrude between the suture lines of the anastomosis.

Antegrade stent placement can be done with or without a guidewire. Performing stenting without a guidewire is possible, but it takes more time and has a higher failure rate.[2] For 3 or 3.5 Fr stents, a 0.018-sized guidewire is typically utilized, which features both soft and stiff ends. The soft end of the guidewire is advantageous for navigating the ureter, particularly at the lower vesicoureteral junction. However, this soft end lacks the rigidity needed to straighten the curve of the DJ stent, making laparoscopic placement more challenging. As a result, the stiff end of the guidewire is often used to traverse the pelviureteric junction obstruction, facilitating the passage through the upper urinary tract.

While employing the stiff end of the guidewire can aid in navigating the upper tract, it introduces a significant risk: the potential for the guidewire to become caught within the ureteral folds, especially in the lower ureter. This complication can result in unsuccessful stent placement. To address this challenge, several techniques have been described in the literature, including the use of Veress needles,[2] Chiba needles,[3] angio catheters,[4] Amplatz sheaths,[5] and intravenous cannulas.[6] However, it is important to note that most of these methods have primarily been reported in older pediatric patients. Infants present unique challenges due to their narrower ureteral caliber and a higher risk of obstruction at the vesicoureteral junction. Consequently, infants are often underrepresented in studies or included in limited numbers. Our approach simplifies the placement of the soft end of the guidewire, making it less likely to become trapped within the ureteral mucosa. In our experience, this method has proven to be effective for antegrade stent placement in this patient population.

Our method utilizes readily available operating room equipment, namely a 14-G IV cannula and a DJ stent set with a guidewire. The pusher, being more flexible than other tools such as the Veress needle, lowers the risk of ureteral injury and allows for easier navigation through anatomical curves. In addition, this approach minimizes excessive tension on the hitch stitch, which is particularly important in infants whose pelvic tissues are more delicate compared to adults.

Several studies have documented the time required for antegrade stent placement over a guidewire, which ranges from 5 to 7 min.[2,5] In our study involving 20 infants, the average procedure time was 5.30 min [Video 1], with successful outcomes in all cases. Comparable results have been reported in a cohort of 25 children, with a mean age of 6.5 years, where a Veress needle was employed.[2]

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.