A large body of research has been conducted to verify the efficacy and safety of management approaches of high-grade pediatric renal traumas so far [3, 5, 9]. Despite this going on research, the conservative management still warrants a cautious application in practice because it may be confronted with the high variability of the definition of hemodynamic stability and the difficulty of decision-making in these high-grade traumas [2, 4]. In the current study, hemodynamic stability was defined based on the blood pressure and clinical responses to resuscitations. In addition, the conservative treatment warrants close monitoring and follow-up of patients, especially during the first few hours [4]. Hemodynamic stability is acknowledged as the most important factor in the assessment and management of blunt trauma patients. However, there is no consensus on the length of time during which the patient should be considered unstable and explored [2, 4]. We considered the trials of resuscitation successful when the patient could maintain stability for the first 24 h with no more than two trials of adjustment of blood pressure.

Furthermore, conservative management may be followed by a potential relative decline in renal function [4]. This effect warrants a long-term and accurate evaluation of the kidney by radioisotope studying [3]. The current study did not assess this long-term outcome because it targeted the stage of hemodynamic stabilization and its effect on the allocation to the management plan.

To make a decision about conservation in children with major renal trauma, there should be contingent safety and feasibility criteria available to guarantee timely intervention. In addition, this warrants the availability of a full range of flexibility in equipment and manpower for urgent exploration of the patient, whenever the indication for surgical intervention supervenes. The most critical period is the time from the presentation of the patient to the time of decision making, when the challenges of stabilizing a patient with a major hemorrhage are at their maximum [2, 4, 10]. In the current study, this part of management was achieved without threatening the lives of patients. Surgical intervention was timely for unstable patients who failed to achieve or maintain hemodynamic stabilization.

The mechanism of high-grade renal trauma is usually blunt injury, and grades 3 and 4 represent the highest proportion in those patients [3, 7]. In addition, hemodynamically stable patients with grade 5 renal trauma represent a rare event in high-grade renal trauma [11]. Similarly, the current results showed that all patients had blunt injuries, and grades 3 and 4 represented the highest proportions. In addition, more than 90% of patients in the unstable group had traumas of grade 4 or 5, while more than 50% in the stable group had traumas of grade 3. Hence, a success rate of 60% for conservative treatment in the unstable group may be an indicator of the favorable effect of successful initial resuscitation in these patients.

The recent studies showed high overall success rates for the conservative approach, reporting rates up to 92.5% [3.7]. The current results showed a slightly lower rate, but they are still relatively high in these grades of trauma in the context of the literature [2]. However, higher rates can be obtained if the issues of delayed referral and the uncertainty of the outcomes of these modern concepts of treatment have been resolved. Some patients may have a late presentation to our hospital due to the sequential referral protocol from the primary healthcare centers to the tertiary centers.

Extended renal investigations may not be required if the child’s hemodynamic instability persists or if there is no response to blood transfusions that are up to 3 units because immediate exploration is absolutely indicated. Expanding or pulsatile perirenal hematomas represent another indication for surgical therapy. In addition, the other common indications include significant urine extravasation, extensive (> 20%) nonviable tissue, arterial damage, and insufficient staging [12]. The surgical procedures and interventional techniques for management of high-grade renal traumas include renorrhaphy, partial nephrectomy, and nephrectomy. In cases of deeply lacerated kidneys without ischemic or completely separated parenchymal tissues, the collecting system should be sutured with absorbable monofilament sutures. In renorrhaphy, the margins of the lacerated parenchyma are reapproximated carefully, with or without interposing a hemostatic sponge or applying absorbable sealants to the suture. Omental flap interposition may be performed [13]. In the current study, renorrhaphy was performed in only two cases, as a simple approximation and suturing. Similarly, Ishida et al. reported no cases of renorrhaphy among 68 patients [14].

Partial nephrectomy is a higher step in the surgical repair of high-grade renal traumas with devitalized tissues. It is indicated in cases of a completely shattered pole of the kidney that is ischemic and its arterial supply is beyond repair. Early surgical debridement is the best treatment for devitalized renal parenchyma. Intraoperative signs of a devascularized pole or segment of the kidney include complete separation or bluish discoloration of the suspected tissues [13].

There are many indications for total or simple nephrectomy of the injured kidney. They include grade 5 injuries that are deemed irreparable, such as major vascular injuries, a shattered kidney, multiple concurrent injuries, and uncontrolled hemorrhage [2, 13]. Nephrectomy should be carried out if the diagnosis of renal artery thrombosis is postponed and laparotomy is otherwise necessary. If not, it may be decided to let the kidney atrophy and undergo a delayed nephrectomy if high blood pressure starts to appear [13].

The rate of nephrectomy is one of the main outcomes of the management of high-grade renal traumas. Compared to adult trauma, juvenile trauma has a lower nephrectomy rate [2]. It may be as low as 0% [15] or as variably high as 2.9–13% in some studies [14, 16, 17]. The current study showed that the rate of nephrectomy was high relative to the rate of repair, which may refer to the high potential of nephrectomy with surgical exploration. The rate of nephrectomy could be significantly reduced with the implementation of successful conservative management [2, 15]. Although the potential for mortality with high-grade renal trauma represents a significant risk [18], the mortality rate in the current study was at its minimum (0%).

The minimally invasive interventions in pediatric patients include angioembolization techniques, ureteral stents placement or percutaneous drainage of the obstructed kidneys [3,4,5, 19, 20]. The current study included ureteral stent and percutaneous nephrostomy placement in 3 cases only, representing minimally-invasive interventions.

As a prospective study, our study may contribute to filling the gap in research on the hemodynamic effect on management by providing information about the decision-making in the management of pediatric high-grade renal traumas. In addition, it allowed patient selection criteria that helped recruit the patients and manage them without harmful effects from the application of the conservative approach.

Limitations of his study included the non-randomized allocation of patients to the approach of management. The low incidence of high-grade renal trauma in pediatrics was a cause of the difficulty in recruiting a relatively larger sample size. In addition, this small sample size hindered studying the effect of hemodynamic stability on management in each grade of trauma. Furthermore, the short-term follow-up and evaluation of the kidneys did not allow us to know the extent of effect of trauma on the functions of the preserved kidneys after these high-grade traumas.