Totally Tubeless Percutaneous Nephrolithotomy: Is It Safe and Effective in Preschool Children?

Abstract

Background and Purpose:

After the introduction of tubeless percutaneous nephrolithotomy (PNL), many studies conducted in adult patients have confirmed its efficacy and safety. There are limited studies reporting that tubeless PNL can be safely applied in children, however. Furthermore, there are no reports that evaluate the use of totally tubeless PNL in children. The present study evaluates the results of totally tubeless PNL in preschool children.

Patients and Methods:

The data of children seen in our clinic who were considered suitable for totally tubeless PNL were analyzed. Of 16 children, 8 patients underwent totally tubeless PNL (group 1) and 8 standard PNL (group 2). The two groups of patients were compared with regard to length of hospitalization, analgesic requirements, transfusion rates, hemoglobin (Hb) decrease, and immediate, early, and late complications.

Results

: The mean ages of the patients were 56.6 months (9–84 mos) and 56.0 months (5–84 mos), and the mean follow-up was 21.5 months (3–44 mos) and 43.4 months (36–54 mos) in groups 1 and 2, respectively. Both groups were similar with regard to age, stone size, Hb change, and complications. Although operation duration, hospitalization period, and analgesic requirement were less in the totally tubeless PNL group, these differences were not statistically significant.

Conclusions:

The latest application of PNL, totally tubeless PNL, is also a safe and effective procedure in very small children if they are selected properly and if the surgeon has sufficient experience with the procedure. More studies with a higher number of participants are needed, however, to confirm that totally tubeless PNL increases the comfort of pediatric patients, decreases their hospitalization period, and is more economical.

Introduction

A fter the introduction of tubeless percutaneous nephrolithotomy (PNL) in 1997, many studies conducted in adult patients have confirmed its efficacy and safety. The interventions made with tubeless PNL were less painful, less troublesome, and resulted in shorter hospitalization periods.^1

–5 Since its first application, there have been limited studies reporting that tubeless PNL could be safely applied in children as well. These reports were generally confined to school-aged children whose body dimensions were comparable to those of adults^4,6; there are no studies that concern the outcomes of tubeless PNL applications in infants. The limited number of studies that have been conducted with children can be attributed primarily to the scarce number of pediatric urolithiasis cases and, hence, experiences that confirm the reliability of tubeless PNL.

In our clinic, totally tubeless PNL has been applied since April 2006 in children with an appropriate indication. To our knowledge, there have not been any previous reports that evaluate the use of totally tubeless PNL in children. The present study evaluates the results of the interventions made with PNL to analyze the efficiency and reliability of totally tubeless PNL in preschool children.

Patients and Methods

The data of children seen in our clinic who were considered suitable for totally tubeless PNL were analyzed retrospectively. In our clinic, totally tubeless PNL has been applied since April 2006 in children with an appropriate indication. Thus, we were able only to compare preschool children, who underwent totally tubeless PNL, with the children who met the criteria for totally tubeless PNL but were treated using a standard procedure before April 2006. As the present study is a retrospective study, there was no randomization.

Of 16 children, 8 patients underwent totally tubeless PNL and 8 standard PNL. The two groups of patients—totally tubeless PNL (group 1) and standard PNL (group 2)—were compared with regard to length of hospitalization, analgesia requirements, transfusion rates, hemoglobin (Hb) decrease, and immediate, early, and late complications. One patient from group 2 in whom two accesses were applied was excluded from the study.

The criteria taken into consideration to apply totally tubeless PNL were as mentioned in previous reports^6,7:

Stone size larger than 1.5 cm.

Stone size smaller than 1.5 cm if: Extracorporeal shock wave lithotripsy (SWL) as primary treatment failed, or pelvicaliceal anatomy was not favorable for clearance after SWL.

Parental preference for PNL as the first-line treatment.

No serious bleeding or perforation in the collecting system during the operation.

Stone free or clinically insignificant residual fragments (<4 mm) at the end of the procedure, only one access, and no major arterial bleeding.

The absence of staghorn stone, solitary kidney, or kidneys with congenital anomalies.

No renal failure on admission.

PNL technique

The procedure was started with ureteral catheter insertion. The patient was then placed in the prone position. A mixture of methylene blue and opaque substance was flushed through the ureteral catheter, and the posterior calix was punctured. Dilation was performed using an Amplatz sheath up to 20F, and a 17F nephroscope (Storz, Tuttlingen, Germany) was used in all patients. The stone fragmentation was performed with a pneumatic lithotripter in all patients. At the end of the operation, residual stones were determined fluoroscopically, and antegrade pyelography was performed to evaluate the collecting system. The ureteral catheters were removed at the end of the operation in both groups.

In the patients who underwent standard PNL, 12F Foley catheters were placed as a nephrostomy tube. The nephrostomy tube was first clamped on postoperative day 1 to 2, and if the patient was comfortable, afebrile, and there was no drainage from the nephrostomy site, the tube was removed. The patients were discharged when there was no leakage from the PNL site and the urine was clear.

Urinalysis and culture, determintion of the serum creatinine level, and Hb value, abdominal and pelvic ultrasonogrphy, and plain abdominal radiography were performed in all patients preoperatively. Intravenous urography and/or CT evaluation was performed in all patients. Urinalysis, determination of serum creatinine, electrolytes, and Hb values, plain abdominal radiography, and abdominal and pelvic ultrasonography were repeated in all patients 24 to 48 hours postoperatively.

Statistical analysis

In this study, all statistical analyses were calculated using SPSS 15.0 statistical package program and the results were evaluated according to significance level at 0.05. Because of the small number of observations and the non-normally distributed data, nonparametric statistical methods were used for all analyses. The Mann-Whitney U test was used to compare two independent samples on continuous variables, and the Wilcoxon test was used to compare two dependent samples on continuous variables.

Results

The mean ages of the patients were 56.6 (9-84 months) and 56.0 (5-84 months) and the mean follow-up was 21.5 (3-44 months) and 43.4 (36-54 months) in Groups 1 and 2, respectively. Stones were located in the lower calyx (n = 2), pelvis (n = 5), and upper calyces (n = 1) in Group 1, and in the pelvis (n = 6) and upper calyces (n = 1) in Group 2. PNL was performed primarily in pelvic stones >20 mm and lower pole stones >10 mm. In two cases from Group 1, with stones lower than 20 mm, one had lower cystine stone and the other underwent PNL due to parental preference. In two patients from Group 2, PNL was preferred as the part of the stones were in lower poles.

The mean operation times were 51.8 (40–75 min) and 68.5 (40–120 min), respectively, which represents the initial cystoscopy, retrograde catheter placement and the time required to turn the patient prone. None of the patients required blood transfusion due to insignificant blood loss during or after the operation or according to Hb levels postoperatively. The mean stone burden was 17.6 (15–24 mm) and 19.1 (16–24 mm), respectively (Table 1). All patients were stone-free after the intervention and none required a conversion to open surgery. There were no major perioperative complications. In two patients from Group 1 and one from Group 2, fever occurred on postoperative day 2. The patients recovered with the administration of antibiotics.

Table 1.

The Preoperative, Perioperative, and Postoperative Characteristics of the Patients in Groups 1 and 2

	Totally tubeless PNL group 1	Standard PNL group 2	P value
Age (months)	56.6 ± 26.99	56.0 ± 26.83	0.903
Stone size (mm)	17.6 ± 3.5	19.1 ± 4.45	0.318
Operative time (min)	51.8 ± 13.34	68.5 ± 29.82	0.243
Preoperative/postoperative Hb change	0.31 (0–1)	0.17 (0–0.3)	0.833
Major complication	–	–
Minor complication (fever)	2	1
Residual stone	–	–
Hospitalization (d)	2.2 ± 1.1	2.8 ± 1.34	0.335
Postoperative 1st day analgesic requirement	1.3 (0–3)	2.5 (1–4)	0.082
Postoperative 2nd day analgesic requirement	0.7 (0–1)	1.4 (0–2)	0.056

PNL = percutaneous nephrolithotomy; Hb = hemoglobin.

Intravenous patient-controlled anesthesia (IV PCA) was applied in one child in each group for analgesia immediately after the intervention. These children were comfortable in the postoperative period and no further analgesics were required after 12 and 24 hours. In other patients, the mean demand for analgesics (oral, per rectum or IV) during the first and second days was 1.3, 0.7 in Group 1 and 2.5, 1.4 in Group 2. Analgesic demand, dose, and type are given in Table 2.

Table 2.

Postoperative Pain Management of the Children

		Postop. 1. Day			Postop. 2. Day
	Pts	Demand	Analgesic Type	Total Dose	Demand	Analgesic Type	Total Dose
Group 1	1	3	Ibuprofen	300 mg	1	ibuprofen	100 mg
	2	2	Ibuprofen	200 mg	1	ibuprofen	100 mg
	3	PCA	Tramadol	undetermined	0	0	0
	4	0	0	0	0	0	0
	5	1	Paracetamol	120 mg	1	paracetamol	120 mg
	6	1	Ibuprofen	100 mg	1	ibuprofen	100 mg
	7	1	Ibuprofen	100 mg	1	ibuprofen	100 mg
	8	1	Ibuprofen	100 mg	1	ibuprofen	100 mg
Group 2	1	3	Ibuprofen	300 mg	2	ibuprofen	200 mg
	2	2	Ibuprofen	200 mg	1	ibuprofen	100 mg
	3	1	Ibuprofen	100 mg	1	ibuprofen	100 mg
	4	PCA	Tramadol	undetermined	0	0	0
	5	3	Ibuprofen	300 mg	2	ibuprofen	200 mg
	6	4	Ibuprofen	400 mg	2	ibuprofen	200 mg
	7	2	Paracetamol	240 mg	2	paracetamol	240 mg
	8	3	Ibuprofen	100 mg	2	ibuprofen	200 mg

PCA = patient-controlled anesthesia.

The mean hospitalization was 2.2 (1–4 days) and 2.8 (1–5 days), respectively. Although the hospitalization period of the totally tubeless PNL patients was shorter than that of Group 2, there was no statistically significant difference between the two groups. There were also no significant differences between the groups in terms of mean stone volume, operation time, Hb and creatinine level change, and hospitalization (Table 1).

Discussion

PNL was used on a widespread basis after its first description in stone treatment in adults in 1976.⁸ The development and commonplace use of PNL in pediatrics, however, has been slower and more cautious.^9
–11 The first successful use of pediatric PNL was reported in children with a mean age of 14 whose bodily dimensions were comparable to those of adults.¹² In the following years, studies that reported the outcomes of PNL in preschool aged patients offered PNL as a standard treatment of stones in children aged 5 and younger.¹³ Similarly, tubeless PNL has been well defined and reported in adult patients; however, reports regarding the use of tubeless PNL in pediatrics remain limited.

Khairy Salem and associates⁶ were the first to evaluate their initial experiences to determine the indications and limitations of tubeless PNL in children. They reported that tubeless PNL was less painful, less troublesome, and shortened the hospital stay of the child. In their study, they placed ureteral stents in all patients, but no nephrostomy tubes. Ureteral stents might cause irritative voiding symptoms—for example, dysuria and pollakiuria—and removal of the stent at a later time results in additional morbidity.¹⁴ To overcome this drawback, a totally tubeless PNL is offered in a selected group of patients and, hence, no stent was placed; furthermore, it was claimed that the self-peristalsis of the ureter would lead to the best drainage possible.¹⁴ The effectiveness and reliability of totally tubeless PNL have been reported in adult patients, with substantial advantages with regard to morbidity and cost effectiveness when compared with standard PNL.^4,14,15

The application of tubeless PNL in children with appropriate indications has been a standard practice in our clinic since 2006. To our knowledge, there have been no reports that evaluate the use of totally tubeless PNL in children. Moreover, the reports on the use of tubeless PNL in children are generally related to schoolchildren, and the minimum age reported thus far is 4 years. Hence, studies regarding the reliability of this intervention in preschool children are lacking.

In this study, we evaluated the safety and efficacy of totally tubeless PNL in preschool children and compared the outcomes with those achieved using standard PNL. The limitation of this study is the small number of the cases. Although stone diseases are endemic in our region, the ratio of preschool children who underwent PNL is small. In the present study, the results of all preschool children considered eligible for totally tubeless PNL were given. There were 16 children (groups 1 and 2) meeting these criteria. We also mentioned the results of cases who were suitable for totally tubeless PNL but who underwent standard PNL before April 2006. Hence, the follow-up of the patients who underwent standard PNL was longer. It is difficult to come to a conclusion with a small number of cases; however, in the present study, nonparametric statistical methods were used for all analyses. The results were obtained using these nonparametric statistical methods.

In children, we prefer Foley catheters for standard PNL with their balloon deflated. This catheter provides the opportunity to inflate if necessary. Because there was not any bleeding in the patients, however, the balloons were not inflated. No ureteral catheters and Double-J stents were placed in the patients who were undergoing tubeless PNL in our series. The application of totally tubeless PNL was decided according to the characteristics of the patients before the intervention as well as the progress made during the intraoperative process. No major complications developed in any of the patients who underwent totally tubeless PNL.

The outcomes of the children who underwent either totally tubeless or standard PNL were all successful, and the outcomes regarding the other parameters were comparable between the two groups. The PNL procedure time, average hospitalization period, and the analgesic requirement of the patients with totally tubeless PNL were shorter than in the standard PNL group, but these differences were not statistically significant. This is because of the limited number of the participants. The mean process time, including cystoscopy, retrograde catheter placement, and position change, and hospitalization period were shorter or comparable compared with previous studies.^6,9 In contrast, Gupta and colleagues,^4,5 while mentioning the techniques of tubeless and stentless PNL in adult patients, reported that they had reached stones directly without the placement of the retrograde catheter or occlusion balloon. Therefore, the process time in their study was quite short (18 min). Furthermore, the process was applied in that study for stones smaller than 1 cm. In all the other studies that reported the results of totally tubeless PNL, the retrograde catheter was placed in the preoperative period and immediately removed after the intervention. The studies that reported the application of totally tubeless PNL were all limited to adults. There have been no studies that analyzed the effects of ureteral catheter placement vs nonplacement during the PNL procedure in children.

We attribute the shorter hospitalization period in the totally tubeless group to the application of tubeless PNL. The postoperative follow-up of the nephrostomy tube and its removal lengthens the hospitalization period for another 24 hours.

Radiation exposure can be prevented in children by using ultrasonography guidance¹⁶; however, to our knowledge, there are no reports in the literature regarding the use of ultrasonography-guided PNL in infants and very young children. Similar studies reported the use of fluoroscopy in children.^6,9,11
–13 It is well known that there is a positive correlation between the use of fluoroscopic screening time and radiation exposure.¹⁷ Distance, shielding, and time are critical factors that determine radiation exposure. In our clinic, to limit radiation exposure as much as possible, all the cases were treated by senior urologists with an experience of more than 500 PNL cases. Tepeler and coworkers¹⁸ reported that flouroscopic screening time is significantly related to the access number. Hence, in the current series mentioned, the exposure time is kept as limited as possible, and an access more than once is avoided. Furthermore, the genitalia of the children were covered with a lead protection panel. Although radiation exposure was minimized by these precautions, our goal should be no radiation in pediatric PNL cases.

Recently, for a safer tubeless PNL, the use of absorbable hemostatic agents is recommended for access sealing; we could not apply these agents, however, because of financial reasons.^19,20

Conclusions

This latest form of PNL, totally tubeless PNL, which is less painful, less troublesome, and shortens the hospital stay, is also a safe and effective procedure in very small children provided that they are selected properly and the surgeon performing the procedure has the necessary experience. More studies with a higher number of participants are needed, however, to confirm that totally tubeless PNL increases the comfort of small children during the postoperative period, decreases the hospitalization period, and is more economical compared with other treatment options.

Footnotes

Disclosure Statement

No competing financial interests exist.

Abbreviations Used

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