Tratamento não operatório das lesões renais por arma de fogo Non operative management of renal gunshot wounds

Objective: To analyze the experience of nonoperative management (NOM) of renal injuries caused by a firearm projectiles (FAP) in the right thoraco-abdominal region in patients with hemodynamic stability and no signs of peritoneal irritation, highlighting the assessment of the safety of this approach. Methods: This was a prospective study with patients sustaining injuries by FAP in the right thoraco-abdominal region and kidney lesions, treated at the João XXIII Hospital (FHEMIG) in Belo Horizonte, from January 2005 to December 2012. Inclusion criteria were: hemodynamic stability, renal morphofunctional study by CT and no signs of peritoneal irritation. Results: A total of 128 patients met the inclusion criteria of the protocol and underwent NOM for right thoraco-abdominal injury by FAP. Of these, 37 (28.9%) had renal injuries. Trauma indexes: RTS 7.8, ISS16, and TRISS 99%. Lesions grade II and grade III were the most frequent. The most commonly associated intra-abdominal injury was of the liver, present in 81.1% of cases. Two patients (5.4%) had failed nonoperative treatment. Conclusion: The nonoperative treatment of such renal lesions, when properly indicated, has a high success rate, low complication rate and increases the chance of renal preservation. It is safe for well-selected patients in trauma centers with adequate infrastructure, experienced professionals and use of a specific protocol.


INTRODUCTION INTRODUCTION INTRODUCTION INTRODUCTION INTRODUCTION
T he management of penetrating renal trauma has evolved, during the last decades, from the immediate surgical exploration to attempt to preserve kidney to the non-operative treatment (NOM) in selected patients 1 .The advance of imaging techniques and the development of an internationally validated classification of renal trauma 2 improved the severity staging of lesions and facilitated monitoring.In addition, the appreciation of the hemodynamic stability of patients led to better NOM outcomes 3 .
Despite the supposed benefits of nonoperative treatment, a minority of penetrating renal injuries can be treated without surgery by NOM and currently the option is still controversial.However, there is increasing evidence that even high degree renal injuries can be treated safely without intervention in the hemodynamically stable patient 4-6   .
Although renal injuries by firearms are uncommon, they tend to produce complex lesions of the urinary system 6 .By contrast, there are few services that have sufficient number of patients with penetrating renal injuries, especially those by firearms, which allows the study of such cases.
The aim of this study was to analyze the NOM of patients with renal lesions caused by firearm projectiles (FAP) admitted with hemodynamic stability and no signs of peritoneal irritation, with emphasis on the evaluation of the safety of this approach.

METHODS METHODS METHODS METHODS
We conducted a prospective study in patients victims of assault by firearm in the right thoraco-abdominal region, with kidney injury, treated at João XXIII Hospital (FHEMIG), in the period from January 2005 to December 2012.Patients who met the inclusion criteria determined by the Protocol of the Service of General Surgery and Trauma of HJXXIII took part in this study 7 .The study was approved by the Ethics in Research Committee under No 049/2009.
The protocol of HJXXIII for this type of approach includes injuries exclusively located in the right thoracoabdominal region, caused by FAP, which penetrate between ribs and do not cross the midline.When admitted to the emergency room these patients must display hemodynamic stability, defined as systolic blood pressure greater than 90 mmHg and heart rat e less than 110 bpm, and no signs of peritoneal irritation.Filling these criteria, they are then compulsorily referred to computed tomography (CT) examination 7 .If there is no complication, the image control will be held two months after trauma, with the objective of analyzing the evolution of wound healing.The patient is then monitored annually for a period of five years from the date of injury.
The data analyzed were: age, gender, trauma indexes, CT result, existing lesions, clinical course, complications and their treatment, duration of hospitalization and death.
The data were stored in a database.The variables were described using measures of central tendency.To test differences in means we used Student's t test.To test differences between proportions we used the chi-square test.

RESULTS RESULTS
During the period, 128 patients met the inclusion criteria of the protocol and underwent NOM for right thoracoabdominal injury by FAP.Of these, 37 (28.9%) had renal injury.The majority (91.9%) were male and the mean age was 24 years.All patients treated conservatively were hemodynamically stable, without signs of peritonitis and underwent computed tomography.The global average of trauma indexes observed were: RTS 7.8; ISS 16; and TRISS 99%.CT findings of the lesions found are described in table 1.
The most frequent injuries were grade II and III.The classification of lesions are listed in Table 2.
Two patients (5.4%) had failed nonoperative treatment, one with grade II injury and one with grade IV injury.Both had associated liver damage and that was the direct cause of the need for laparotomy (choleperitoneum).The most commonly associated intra-abdominal injury was of the liver, present in 81.1% of cases (Figure 1).There was one case of pneumonia (2.7%), one case of urinary tract infection (2.7%) and one death (2.7%) due to associated Traumatic Brain Injury (TBI).The mean hospital stay was seven days.DISCUSSION DISCUSSION DISCUSSION DISCUSSION DISCUSSION Renal lesions occur in about 1 to 5% of all traumas 3,8 , and in 1 to 19% of the penetrating abdominal ones 8 .The use of CT in trauma made its diagnosis more accurate and frequent, allowing the surgeon to study the renal function and establish the magnitude of the kidney injury.CT with intravenous contrast medium, including images of the late phase, is the best method for assessing renal lesions 9 .It provides important information, providing the classification of the lesion, assessing renal vascularization, verifying whether there is a ischemic segment or evidence of active bleeding, and mainly detecting the escape of contrast from the excretory system.
Bleeding and escape of urine from the excretory system are the two major difficulties in addressing renal trauma.The major renal blood flow (each kidney receives about 12% of the cardiac output, or 500 mL/min), suggests that kidney bleedings sometimes need some type of invasive procedure to stop the bleeding 10 .However, the bleeding arises from the renal lesion in most cases, ceasing spontaneously because it is contained in the retroperitoneum, buffered by the Gerota's fascia.With the advance in endoscopic manipulation of the urinary tract,     particularly with the placement of ureteral stent (double-J catheter) inside the renal pelvis, lesions of the excretory system could be addressed in this way, without the need for surgery, except when there is total disruption of the pielo-ureteral junction.
The anatomical location of the right kidney and its close relationship with the visceral surface of the liver explains the high frequency of simultaneous injury of these two organs (Figure 1).In this study, the frequency of this association was 81.08%.One need to take special care when the inlet is in the dorsal region and there is concomitant liver and kidney injury.In this circumstance, it is necessary to make sure that there are no colonic lesions when electing NOM.The reconstruction of the trajectory of the projectile by axial, coronal and sagittal images in multidetector CT is essential to rule out injury to the intestine.When in doubt, surgery is the safest option.
In penetrating trauma, especially by FAP, the surgical treatment of renal lesions is the most suitable due to the high frequency of associated intra-abdominal injuries [11][12][13] .In patients with renal injury grades I and II, when surgically explored, the bleeding has ceased and there is no further need for a hemostatic procedure.Recognizing these lesions preoperatively and not manipulating them during surgery is the currently recommended conduct by the literature.This type of conduct is considered NOM by many authors 1,6,14,15 .In patients who have not had the chance to be submitted to imaging before surgery, it is recommended to check the presence, functionality and viability of the contralateral kidney before exploring the renal hematoma 8 .
Based on these assertions, NOM of isolated kidney injuries was proposed in selected cases.In penetrating trauma by stab wounds, 51-77% of patients with renal injury can be addressed without surgery, since the inclusion criteria of the protocol are followed.The success rate has reached 95% 13,16 .However, in penetrating injuries from firearms, the selection of patients to indicate NOM should be carefully and strictly follow the proposed inclusion criteria.It should only be adopted in patients who do not have immediate surgical indication and can be submitted to contrast-enhanced CT to confirm and study the renal injury 17 .With current treatment options, most of haemodynamically stable patients with renal lesions can safely be subjected to such treatment 3 , provided that there is no associated injury imposing surgery.The authors who propose this approach can perform it in 10-40% of renal injuries from firearms, obtaining a success rate ranging from 91 to 100% 1,6,12,15,17 .
In 1985, Heyns et al. 4 conducted a randomized controlled trial of mandatory surgery versus NOM in patients with renal stabbing wounds, asymptomatic, diagnosed by pyelography.They realized that the NOM reduced the number of complications and decreased the length of hospital stay when compared with mandatory surgical treatment.Exploratory laparotomy used to be recommended for all patients who presented with renal injury by penetrating trauma.However, nowadays the nonoperative treatment has been accepted with greater frequency in patients with lesions grade I, II or III by penetrating trauma, where there are no hollow viscera injuries or hemodynamic instability 3 .
Velmahos et al. 18 conducted a study that included 1,856 patients with abdominal injury by firearms and showed that NOM was a safe method for trauma centers and significantly reduced the rate of unnecessary laparotomy and hospital expenses.
Navsaria et al. 17 obtained a success rate of 90.9% of non-operative treatment in a study with 33 patients suffering from renal injury by firearms.In the present study, considering only the renal lesions, there was no need to operate any patient.In this sample the need for surgical intervention occurred exclusively from complications of the liver injury.
In 2010, in a retrospective study from Muir et al. 9 , one of every three patients with penetrating renal trau- ma underwent NOM, although one in five of these individuals needed, ultimately, angiographic or surgical treatment.Based on these data, we concluded that the routine use of angiography can reduce failures in NOM and improve the prognosis of patients undergoing this type of treatment.
Bjurlin et al. 1 carried out a comparative analysis showing that NOM of penetrating renal injuries, including those by firearms, has lower mortality, lower incidence of transfusions and a shorter stay in intensive care compared with patients undergoing nephrectomy, but rates similar to those undergoing nephrorraphy.
Persistent bleeding is a common complication in severe lacerations of the renal cortex and medulla, seen commonly in penetrating renal trauma, especially stabbing ones.It occurs in 13-25% of renal injuries grades III and IV treated conservatively.Clinically, the patient presents with persistent hematuria, low hematocrit or hemodynamic instability 3 .Bleeding from segmental renal artery pseudoaneurysms and traumatic arteriovenous fistulas are not uncommon findings in renal penetrating trauma 1 .Unfortunately, NOM of renal vascular lesions is often unsuccessful, invasive procedures being necessary in most cases.In such cases, selective embolization of segmental arteries is highly effective 9 .However, angiography with or without embolization remains a rarely used procedure with renal penetrating trauma 9 .The treatment by interventional radiology in selected patients helped reduce the need for surgical treatment 3 .
NOM provides a greater chance of renal preservation, decreases length of stay, cost of treatment and the rate of complications.According to Cheng et al, lesions with contrast escape from the excretory system have a higher possibility of complication and NOM failure 19 .The Eastern Association for the Surgery of Trauma revised the available literature on the treatment of penetrating re-nal trauma in 2010 and concluded that the evidence is not yet sufficient for the option for NOM of kidney lesions by FAP to be widely recommended and that further studies on this topic are still needed 20 .
The study of NOM of penetrating renal injuries is still a growing field.The present study demonstrated, once again, that the non-operative treatment of these injuries, when properly indicated, has high success and low complication rates and increases the chance of renal preservation.It is safe for well-selected patients in trauma centers with adequate infrastructure, experienced staff and a specific protocol to accomplish it.

Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 -
Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 -CT scan of patient with thoraco-abdominal wound by firearm, with degree III renal injury associated with a degree II hepatic injury.

Table 2 Table 2 Table 2 Table 2 Table 2 -
Stratification of renal injuries according degrees and their relation to NOM failure.