Abstract
Abstract
Background and Objective:
Evaluation of the feasibility, safety, and outcome of laparoscopic heminephrectomy for duplex kidneys in children above and below the age of 12 months.
Patients and Methods:
The transperitoneal surgical technique included division of the parenchyma with a sealing device (LigaSure™; Covidien, Mansfield, MA) and amputation of the ureter as low as possible. A follow-up study was performed. Patients' records were analyzed retrospectively for operative details and postoperative complications. Long-term outcome was assessed during follow-up visits and a final telephone interview. Outcome was compared between two groups: Group 1 (G1), age at surgery<12 months; Group 2 (G2), age at surgery >12 months.
Results:
Between July 2004 and September 2012, in total, 22 laparoscopic heminephrectomies (20 upper poles and 2 lower poles) were performed in 20 patients (G1, 12 cases; G2, 10 cases). A mean (range) age at surgery was 7.1 (3–11) months in G1 and 49.4 (15–128) months in G2. Mean (range) operative time was 152 (81–220) min in G1 and 197 (90–265) min in G2 (P=.06). All procedures were completed laparoscopically. Major postoperative complication was one urinoma in G1, which was surgically revised. Mean hospital stay was 3.6 days (G1, 4.0 days; G2, 3.1 days). During long-term follow-up (median, 5.2 years) febrile urinary tract infections occurred to the same extent in both groups (G1, 1/12; G2, 2/10; P=.57).
Conclusions:
Laparoscopic transperitoneal heminephrectomy for duplex kidneys is safe and feasible even in small infants. Long-term results are excellent irrespective of the patient's age.
Introduction
For transperitoneal heminephrectomy, it remains largely unclear whether or not this technique is equally safe and effective even in very young children. Therefore, in the present study we aimed to evaluate the feasibility, safety, and long-term outcome of transperitoneal heminephrectomy in infants and children above and below the age of 12 months.
Patients and Methods
Patients
All patients who underwent laparoscopic heminephrectomy in our tertiary pediatric surgical center between 2004 and 2012 were enrolled in this comparative retrospective follow-up study. The study was approved (approval number 1567-2012) by the Institutional Review Board of Hannover Medical School, Hannover, Germany.
For further analysis, cases were allocated to two different groups: Group 1 (G1) (age at surgery<12 months) and Group 2 (G2) (age at surgery >12 months). All patients underwent preoperative ultrasound, voiding cystourethrography, and renal scintigraphy. Results of preoperative imaging and indications for surgery are summarized in Table 1.
G1, group 1; G2, group 2; NS, not significant; UTI, urinary tract infection.
Surgical technique
With the patient under general anesthesia, a 10-mm trocar (Karl Storz, Tuttlingen, Germany) was introduced infraumbilically via minilaparotomy. The abdomen was then insufflated with carbon dioxide using a maximum pressure of 8–10 mm Hg and a maximum flow of 5 L/minute. A 10-mm, 30°, 45-cm scope (Karl Storz) was introduced through the umbilical port. Under direct vision, two or three (depending on the operated side) additional working ports (3.5 and 5 mm) were inserted pararectally cranial and caudal to the umbilicus in order to gain a 60° manipulation angle. Patients were then placed in a semilateral position with the ipsilateral side elevated to obtain maximum exposure of the left or right upper quadrant. The colon was mobilized laterally to expose the ureter and the anterior renal surface. The dilated ureter was dissected toward the renal pedicle. Once it was confirmed that it stemmed from the dysfunctional pole, it was divided inferiorly to the renal pedicle. In the case of upper pole involvement, the upper pole ureter was then passed underneath the renal pedicle to assist with further traction. Distally, the ureter was stich-ligated using polyglactin 910 (Vicryl™; Ethicon, Somerville, NJ) 4/0 and divided with scissors. Vessels supplying the pole were divided using a 5-mm sealing device (LigaSure™; Covidien, Mansfield, MA). Respecting the line of demarcation, the renal parenchyma was divided using the LigaSure device. Finally, monopolar coagulation was used for hemostasis, and interrupted polyglactin 3/0 sutures were additionally placed at the site of resection to seal the cut surface and to avoid blood loss or possible urinary leakage. The remaining portion of the upper pole ureter was followed down to the level of the pelvic inlet. In case of a nonrefluxing ureter, it was not followed down to the bladder. However, in the case of a refluxing ureter, the ureter was followed all the way down to the bladder and ligated there. This was necessary in six children <12 months of age and in six children >12 months of age. The resected specimen was removed through the umbilical incision. Drains or urinary catheters were not inserted. In none of the procedures was simultaneous ureteral reimplantation of the remaining duplex system performed.
Follow-up
Preoperative and postoperative in- and outpatient charts including clinical visits, laboratory studies, and radiologic imaging were retrospectively reviewed using the electronic archiving system (ALIDA) of Hannover Medical School and last accessed in December 2012. Operative notes of all primary and (if applicable) secondary procedures were carefully reviewed for technical details and intraoperative complications. All patients (and parents) were contacted in November/December 2012 for a final standardized follow-up telephone interview.
Classification of postoperative complications
For a better comparison with other studies postoperative complications were classified according to the Clavien system of Dindo et al., 11 which includes the following grades: Grade I, any deviation from the normal postoperative course without the need for pharmacological treatment or surgical, endoscopic, and radiological interventions; Grade II, requiring pharmacological treatment; Grade III, requiring surgical, endoscopic, or radiological intervention; Grade IV, life-threatening event; and Grade V, death of the patient. Urinary tract infections (UTIs) were defined as symptomatic leukocyturia and positive urine culture.
Statistical analysis
Continuous variables with normal distribution were analyzed using Student's t test. The Mann–Whitney rank sum test was used for continuous variables that were not normally distributed. Categorical variables were analyzed using Fisher's exact test. Quantitative data were expressed as mean (range) values. A P value of <.05 was considered statistically significant.
Results
Patient characteristics are summarized in Table 1. Twenty patients underwent laparoscopic transperitoneal heminephrectomy during the study period. In 2 patients, bilateral heminephrectomy was performed, resulting in a total of 22 operations (20 upper pole resections and 2 lower pole resections). Twelve cases were allocated to G1 (age at surgery <12 months) and 10 cases to G2 (age at surgery >12 months). The two groups were significantly different with regard to patient's age (P=.001) and weight (P=.002). No statistical differences were found for gender, side or moiety of the affected duplex kidney, and indication for surgery.
Perioperative data and results of the long-term follow-up (5.2 [0.7–8.4] years) are summarized in Table 2. All heminephrectomies were completed laparoscopically without intraoperative complications.
More than one complication per patient was possible.
G1, Group 1; G2, Group 2; NS, not significant; VUR, vesicoureteral reflux.
Operative time and length of hospital stay
Operative time was shorter in patients operated on below the age of 12 months; however, this difference was not statistically significant (G1 versus G2, 153 minutes versus 197 minutes; P=.06) (Table 2). Length of hospital stay was not significantly different between the groups.
Postoperative complications
In total, 11 complications occurred in 8 of the patients (Table 2). According to the Clavien classification, 11 two incidents (9%) were classified as Grade III (requiring surgical or endoscopic intervention). Seven postoperative incidents in 5 patients were classified as Grade II (Table 2).
Grade III (according to the Clavien classification 11 )
In G1, an 8-month-old patient developed a postoperative urinoma that failed conservative treatment. During revisional laparoscopy 3 weeks after surgery, a leak of the ureteric stump was identified and successfully closed. One child in G2 experienced a 15% decrease of function on postoperative nuclear imaging. As the child showed reflux into the remaining lower duplex system on voiding cystourethrography, an ipsilateral cystoscopic subureteral Deflux® (Salix Pharmaceuticals, Raleigh, NC) injection was performed 3 years after heminephrectomy. Her kidney function remained stable since then. Total loss of function of the remaining hemikidney did not occur in any patient.
Grade I+II (according to the Clavien classification 11 )
In G1, one of 12 patients (8%), who also had a history of posterior urethral valves, experienced a single febrile UTI. Voiding cystourethrography performed at this point also showed reflux into the remaining ureteral stump. The patient was symptom-free under antibiotic prophylaxis at the most recent follow-up.
In G2, 2 of 10 patients (20%) had febrile UTIs. In both of them, voiding cystourethrography showed no evidence of reflux into the ureteral stump, but in one girl bilateral vesicoureteral reflux (VUR) to the remaining hemikidneys was visible, which was successfully treated conservatively (antibiotic prophylaxis).
Asymptomatic postoperative VUR into the remaining hemikidney was diagnosed in 1 more patient, who was managed by close observation only.
Postoperatively, none of the patients in our series exhibited any symptoms due to ureterocele.
Pseudocysts
One child of each group developed asymptomatic pseudocysts located near the resection surface, which resolved spontaneously (Clavien Grade I).
Discussion
In this study we present the first comparison of the feasibility, safety, and long-term outcome after transperitoneal heminephrectomy in infants and children above and below the age of 12 months. Today, heminephrectomy carried out either laparoscopically or retroperitoneoscopically is well established in pediatric urology. However, as observed by other groups (Table 3), the current study shows that operative times of laparoscopic heminephrectomy are longer compared with open techniques.4,13 In addition, our comparative study shows a tendency toward shorter operative times in children with less than 12 months of age (Table 2). We speculate that this was due to the smaller size of the duplex kidney resulting in a faster division of the supplying vessels and renal parenchyma.
NR, not reported.
Postoperative complication rates (Clavien Grade III, requiring surgical, endoscopic, or radiological intervention) of 0–29% have been reported (Table 3), including urinoma, retroperitoneal hematoma, and vascular compromise of the remaining renal moiety. The rate of major complications (Clavien Grade III) of 9% in our series is in line with these data (Tables 2 and 3).
Recurrent febrile UTIs represent the most frequent indication for heminephrectomy and might occur postoperatively as well. In our study, postoperative UTIs occurred in 3 cases (14%). Our subgroup analysis revealed that postoperative UTIs were not more frequent if children were operated on within the first 12 months of age compared with patients older than 12 months (8% versus 20%).
A frequently discussed source for postoperative febrile UTIs represents a reflux into a retained distal ureteral stump, which might require complete surgical excision if conservative treatment fails. 9 In 1 of the 3 patients with postoperative febrile UTIs a refluxive ureteral stump was diagnosed in our series (G1). However, this was a patient with a history of posterior urethral valves and therefore a child with abnormal bladder function, which alone could be the explanation for both the refluxive stump and the UTIs. This child as well as the other 2 patients with postoperative UTIs remained symptom-free under antibiotic prophylaxis at the most recent follow-up.
VUR into the remaining hemikidneys was diagnosed in 3 cases (14%) and managed both conservatively and by subureteral Deflux injection. However, the rate of postoperative VUR may be underreported in the current study as a postoperative voiding cysturethrography was only performed in the case of postoperative UTIs and not on a routine basis in order to avoid radiation exposure.
In summary, this study reveals similar short- and long-term outcomes of patients above and below the age of 12 months at the time of undergoing transperitoneal laparoscopic heminephrectomy. Our results provide further evidence that laparoscopic transperitoneal heminephrectomy for duplex kidneys is equally safe and feasible in older children and small infants under the age of 1 year. Long-term results of both age groups are excellent.
Footnotes
Disclosure Statement
No competing financial interests exist.