Newborns and children have different kidney di- mensions, structures and structures of surrounding tissues than adults. Kidneys are much closer to the skin surface due to less perirenal fatty tissue and subcutane- ous fatty tissue in the pediatric age group. Parenchyma is usually very thin and provides less resistance and support. Dilatation degree is generally extreme in case of blockage, which makes it easier to find a large acces- sible calyx, however; the operation area is too small and it is difficult to position the guidewire in the ureter in case of UP structure. Urine extravasation to perirenal zone, quick disappearance of the collecting system ten- sion, and damaging of the thin renal pelvis due to forc- ing during dilatation are possible in serial dilatations. The catheter can be mislocated in the extrarenal zone in case of a renal pelvis which lost tension. So, there are some differences in the procedures performed on children and adults [5-7].
A limited number of studies were performed on PN in the pediatric age group. High success rates of the procedures are the most interesting aspect of these studies [1-8, 10]. In line with the literature, we obtained successful results from all patients in our study, which we think resulted from the inclusion of only grade II- III and IV hydronephrosis patients.
PN procedure can be applied through different techniques. In the classic Seldinger technique, the re- nal collecting system is accessed with US-guided 17 gauge needle (geotec) and monitored with the opaque matter after observing urine arrival and obtaining a sample. Serial dilatations are performed after inserting 0.035-38 guidewire through a needle in the collecting system and if possible, in the ureter. The catheter is positioned in the renal pelvis through the guidewire, control nephrograms are taken and the catheter is fixed on the skin and the procedure is ended with bag drainage [9]. There is another technique similar to the Seldinger technique in which double needles are used. However, after reaching the collecting system, air or contrast matter is injected to visualize the rear calyx and this calyx is re-entered through US and fluorosco- py and the catheter is positioned in the renal pelvis in a way resembling catheter single needle technique [11]. We inserted catheters with US-guided trocar method in all patients in our study. The duration of the opera- tion was shortened because we did not facilitate most of the steps in the Seldinger method. So, the duration of anesthesia and complication rates, which are risk- ier for the pediatric age group, were decreased. Lack of access needle, guidewire, micropuncture set, dila- tators and contrast matter lowered the operation cost considerably. Our perirenal collection and hematoma risks were minimized as a result of the lack of serial dilatations.
PN is mostly performed under ultrasound and/or fluoroscopic guiding and rarely under CT or MR guided nephrostomy. All three techniques were ap- plied with extremely high success rates. [12-14]. The ultrasound-guided operation had advantages such as the lack of ionizing radiation and contrast matter, portability of ultrasonography and a shorter duration of procedure and anesthesia. Ultrasound-guided ne- phrostomy insertion is usually more simple in children than adults as kidney monitorization is generally easi- er and superficial high-frequency probes are preferred over low-frequency convex probes used in adults [4, 5, 8, 13]. Serial dilatations through guidewire, which may become complex, are sometimes difficult as the kidney is mobile in newborns [3, 4, 7]. The fact that the kidney lacked a deep location provided us the opportunity to use high-frequency superficial probes and follow the catheter easily at each stage.
The use of the US as a guided imaging method also prevents the ionizing radiation the child experiences. Considering that even low doses of radiation pose a risk in the pediatric age group, radiation exposure should be avoided due to the known cumulative effect [14-16]. All PN procedures in our study were performed under US guidance without radiation. Diagnostic antegrade images were acquired in a minimum of 12-24 hours after the operation. Thus, hematoma, which may form due to the procedure in the kidney collecting system; regressed and more informative images were acquired. The pressure of the collecting system was lowered and monitoring related pyelotubular reflux and the possi- bility of sepsis decreased in pyelonephritis patients.
Nephrostomy insertion in adults can be performed sometimes only under local anesthesia and mostly un- der sedation or general anesthesia. However, because children are less compatible, sedation or general an- esthesia is always required [8, 17]. We operated under general anesthesia and a medium level of sedoanalge- sia in all patients. The sedation was started by an ex- perienced anesthesiologist. Stabilization of the intu- bation tube and the respiratory control is difficult in a newborn and child lying in a supine position with a 30-degree slope. General anesthesia was not required in any of our patients. We injected a local anesthetic agent in the access region immediately after the start- ing of sedation, so, there was less requirement of sedo- analgesia. Approximate mean time we spent for quick catheter insertion through US-guided trocar method and for the provision of skin fixation was five minutes. General anesthesia was not required and there were no general anesthesia-related complications. Our results showed that the PN procedure can be performed with- out general anesthesia. We believe that effective seda- tion and anesthesia infiltration can be used in patients to prevent potential complications caused by general anesthesia.
Some studies reported major complications such as hemorrhage, vascular damage, septic shock; renal pel- vis rupture, catheter disposition; perirenal collection, failed drainage related pyelonephritis, urinary leakage; kidney failure and death at different rates [3, 6, 10]. Complications with low possibilities such as intestinal perforation and pneumothorax, empyema, hydrotho- rax and hemothorax were also mentioned in literature [18, 19]. Mild hematuria disappearing in the first 24 hours was the most commonly observed complication in our study (n=25, 52.08%). None of our cases had transfusion requiring massive bleeding. Sepsis risk is highly significant in stone-related pyonephrosis [5]. Antibiotic treatment was effective in two patients with mild infection findings after the operation. None of our patients had sepsis.
Ureteropelvic junction and ureterovesical junction stenosis were reported as the most common indica- tions with an approximate rate of 87% in PN cases in the pediatric age group [1, 6, 8, 16]. The indications in our study (75%) were in line with the literature. The duration of PN ranged from three to 120 days based on etiology. Pediatric surgeons waited to perform the sur- gical operations in newborns, infants and pre-school children with very low body mass indexes and body weights. During this period, three patients experienced spontaneous catheter removal or disposition at home. The patients received opaque matter through the cath- eter tract and after monitoring the collecting system, the catheter was inserted from the fistula tract without entering the new collecting system.
Exclusion of the patients with grade zero and I dila- tation from our study increased the success of our pro- cedure while also being a limitation of our study. Not using a catheter much thicker than the needle prevent- ed repetitive intervention and it should only be applied by doctors with adequate experience.
Conflict of interest
All authors declare no conflict of interest.
Financial Disclosure
The authors have declared no financial support.
Ethical Approval
The study was approved by the Ethics Committee of Necmettin Erbakan University (Approval number: 2020/2307 ) and written informed consent was received from all participants. The study protocol conformed to the ethical guidelines of the Helsinki Declaration.
CONCLUSION
Newborns and children have different kidney di- mensions, structures and structures of surrounding tissues than adults. Kidneys are much closer to the skin surface due to less perirenal fatty tissue and subcutane- ous fatty tissue in the pediatric age group. Parenchyma is usually very thin and provides less resistance and support. Dilatation degree is generally extreme in case of blockage, which makes it easier to find a large acces- sible calyx, however; the operation area is too small and it is difficult to position the guidewire in the ureter in case of UP structure. Urine extravasation to perirenal zone, quick disappearance of the collecting system ten- sion, and damaging of the thin renal pelvis due to forc- ing during dilatation are possible in serial dilatations. The catheter can be mislocated in the extrarenal zone in case of a renal pelvis which lost tension. So, there are some differences in the procedures performed on children and adults [5-7].
A limited number of studies were performed on PN in the pediatric age group. High success rates of the procedures are the most interesting aspect of these studies [1-8, 10]. In line with the literature, we obtained successful results from all patients in our study, which we think resulted from the inclusion of only grade II- III and IV hydronephrosis patients.
PN procedure can be applied through different techniques. In the classic Seldinger technique, the re- nal collecting system is accessed with US-guided 17 gauge needle (geotec) and monitored with the opaque matter after observing urine arrival and obtaining a sample. Serial dilatations are performed after inserting 0.035-38 guidewire through a needle in the collecting system and if possible, in the ureter. The catheter is positioned in the renal pelvis through the guidewire, control nephrograms are taken and the catheter is fixed on the skin and the procedure is ended with bag drainage [9]. There is another technique similar to the Seldinger technique in which double needles are used. However, after reaching the collecting system, air or contrast matter is injected to visualize the rear calyx and this calyx is re-entered through US and fluorosco- py and the catheter is positioned in the renal pelvis in a way resembling catheter single needle technique [11]. We inserted catheters with US-guided trocar method in all patients in our study. The duration of the opera- tion was shortened because we did not facilitate most of the steps in the Seldinger method. So, the duration of anesthesia and complication rates, which are risk- ier for the pediatric age group, were decreased. Lack of access needle, guidewire, micropuncture set, dila- tators and contrast matter lowered the operation cost considerably. Our perirenal collection and hematoma risks were minimized as a result of the lack of serial dilatations.
PN is mostly performed under ultrasound and/or fluoroscopic guiding and rarely under CT or MR guided nephrostomy. All three techniques were ap- plied with extremely high success rates. [12-14]. The ultrasound-guided operation had advantages such as the lack of ionizing radiation and contrast matter, portability of ultrasonography and a shorter duration of procedure and anesthesia. Ultrasound-guided ne- phrostomy insertion is usually more simple in children than adults as kidney monitorization is generally easi- er and superficial high-frequency probes are preferred over low-frequency convex probes used in adults [4, 5, 8, 13]. Serial dilatations through guidewire, which may become complex, are sometimes difficult as the kidney is mobile in newborns [3, 4, 7]. The fact that the kidney lacked a deep location provided us the opportunity to use high-frequency superficial probes and follow the catheter easily at each stage.
The use of the US as a guided imaging method also prevents the ionizing radiation the child experiences. Considering that even low doses of radiation pose a risk in the pediatric age group, radiation exposure should be avoided due to the known cumulative effect [14-16]. All PN procedures in our study were performed under US guidance without radiation. Diagnostic antegrade images were acquired in a minimum of 12-24 hours after the operation. Thus, hematoma, which may form due to the procedure in the kidney collecting system; regressed and more informative images were acquired. The pressure of the collecting system was lowered and monitoring related pyelotubular reflux and the possi- bility of sepsis decreased in pyelonephritis patients.
Nephrostomy insertion in adults can be performed sometimes only under local anesthesia and mostly un- der sedation or general anesthesia. However, because children are less compatible, sedation or general an- esthesia is always required [8, 17]. We operated under general anesthesia and a medium level of sedoanalge- sia in all patients. The sedation was started by an ex- perienced anesthesiologist. Stabilization of the intu- bation tube and the respiratory control is difficult in a newborn and child lying in a supine position with a 30-degree slope. General anesthesia was not required in any of our patients. We injected a local anesthetic agent in the access region immediately after the start- ing of sedation, so, there was less requirement of sedo- analgesia. Approximate mean time we spent for quick catheter insertion through US-guided trocar method and for the provision of skin fixation was five minutes. General anesthesia was not required and there were no general anesthesia-related complications. Our results showed that the PN procedure can be performed with- out general anesthesia. We believe that effective seda- tion and anesthesia infiltration can be used in patients to prevent potential complications caused by general anesthesia.
Some studies reported major complications such as hemorrhage, vascular damage, septic shock; renal pel- vis rupture, catheter disposition; perirenal collection, failed drainage related pyelonephritis, urinary leakage; kidney failure and death at different rates [3, 6, 10]. Complications with low possibilities such as intestinal perforation and pneumothorax, empyema, hydrotho- rax and hemothorax were also mentioned in literature [18, 19]. Mild hematuria disappearing in the first 24 hours was the most commonly observed complication in our study (n=25, 52.08%). None of our cases had transfusion requiring massive bleeding. Sepsis risk is highly significant in stone-related pyonephrosis [5]. Antibiotic treatment was effective in two patients with mild infection findings after the operation. None of our patients had sepsis.
Ureteropelvic junction and ureterovesical junction stenosis were reported as the most common indica- tions with an approximate rate of 87% in PN cases in the pediatric age group [1, 6, 8, 16]. The indications in our study (75%) were in line with the literature. The duration of PN ranged from three to 120 days based on etiology. Pediatric surgeons waited to perform the sur- gical operations in newborns, infants and pre-school children with very low body mass indexes and body weights. During this period, three patients experienced spontaneous catheter removal or disposition at home. The patients received opaque matter through the cath- eter tract and after monitoring the collecting system, the catheter was inserted from the fistula tract without entering the new collecting system.
Exclusion of the patients with grade zero and I dila- tation from our study increased the success of our pro- cedure while also being a limitation of our study. Not using a catheter much thicker than the needle prevent- ed repetitive intervention and it should only be applied by doctors with adequate experience.
Conflict of interest
All authors declare no conflict of interest.
Financial Disclosure
The authors have declared no financial support.
Ethical Approval
The study was approved by the Ethics Committee of Necmettin Erbakan University (Approval number: 2020/2307 ) and written informed consent was received from all participants. The study protocol conformed to the ethical guidelines of the Helsinki Declaration.