You are in: eMedicine Specialties > Urology > Trauma Renal TraumaArticle Last Updated: Jun 12, 2006AUTHOR AND EDITOR INFORMATIONSection 1 of 11
  Author: Douglas M Geehan, MD, Associate Professor, Department of Surgery, University of Missouri at Kansas City Douglas M Geehan is a member of the following medical societies: American College of Surgeons, American Institute of Ultrasound in Medicine, American Medical Association, Association for Academic Surgery, Phi Beta Kappa, Society of American Gastrointestinal and Endoscopic Surgeons, and Society of Critical Care Medicine Coauthor(s): Richard A Santucci, MD, FACS, Chief of Urology, Detroit Receiving Hospital; Specialist-in-Chief of Urology, Detroit Medical Center; Chief of Urologic Trauma Surgery, Sinai Grace Hospital; Director, The Center for Urologic Reconstruction Editors: Peter Langenstroer, MD, Assistant Professor, Department of Surgery, Division of Urology, Medical College of Wisconsin; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; J Stuart Wolf, Jr, MD, FACS, David A Bloom Professor of Urology, Director, Division of Minimally Invasive Urology, Department of Urology, University of Michigan Medical Center; Stephen W Leslie, MD, FACS, Founder and Medical Director of the Lorain Kidney Stone Research Center, Clinical Assistant Professor, Department of Urology, Medical College of Ohio Author and Editor Disclosure Synonyms and related keywords: renal trauma, renal laceration, renal contusion, kidney trauma, kidney laceration, abdominal trauma, blunt trauma, blunt force trauma, renal vascular injury, gunshot wound, stab wound, motor vehicle crash, sports injury, urologic endoscopy, endourologic procedures, extracorporeal shock-wave lithotripsy, ESWL, renal biopsy, percutaneous renal procedure, diagnostic peritoneal lavage, missile injury, hematuria INTRODUCTIONSection 2 of 11
  Renal trauma may manifest in a dramatic fashion for both the patient and the clinician. The incidence of renal trauma somewhat depends on the patient population being considered. Renal trauma accounts for approximately 3% of all trauma admissions and as many as 10% of patients who sustain abdominal trauma. Also, renal trauma may occur in settings other than those thought of as a classic trauma setting. The approach to renal injuries has changed over time, requiring diligent attention to recent literature. Namely, the tolerance for nonoperative or expectant management has increased, even in the most seriously injured kidneys, replacing the past tendency toward aggressive renorrhaphy. ProblemMost renal trauma occurs as a result of blunt trauma. Renal injuries may be generally divided into 3 groups: renal laceration, renal contusion, and renal vascular injury. All subsets of renal trauma require a high index of clinical awareness and prompt evaluation and management. FrequencyThe frequency of renal injury somewhat depends on the patient population being considered. Renal trauma accounts for approximately 3% of all trauma admissions and as many as 10% of patients who sustain abdominal trauma. EtiologyThe mechanism of injury should alert the clinician to the possibility of renal trauma. The following list is not all-inclusive, but it highlights the major mechanisms that generate renal injuries.
ClinicalThe diagnosis of renal injury begins with a high index of clinical awareness. The mechanism of injury provides the framework for the clinical assessment. Particular attention should be paid to complaints of flank or abdominal pain. Urinalysis, both gross and, if necessary, microscopic, should be performed in patients who are thought to have renal trauma. Based on these initial measures, radiographic or operative investigation may follow. INDICATIONSSection 3 of 11
Most blunt renal injuries are low-grade; therefore, they are usually amenable to treatment with observation and bed rest alone. Penetrating trauma is more likely to be associated with more severe renal injury, thus requiring a higher index of clinical awareness. Further, penetrating trauma is more often associated with other abdominal injuries requiring laparotomy, thus providing the opportunity for intraoperative renal staging and/or repair. Patients with indications for emergent exploration include those with hemodynamic instability. Expanding hematomas or active hemorrhage suggests the possibility of high-grade renal injury. Patients with penetrating trauma who are stable and do not require urgent laparotomy for other possible intra-abdominal injuries may be observed without immediate renal exploration. Unrelenting gross hematuria may require urgent exploration. However, the presence of a renal contusion does not typically require specific intervention. Findings from imaging studies may appear quite alarming, but most renal contusions resolve, particularly if the lesion appears to be of grade I-III. RELEVANT ANATOMYSection 4 of 11
In most instances, the kidneys are paired retroperitoneal structures. They lie against the psoas muscles. The superior aspect of the kidneys is somewhat protected by the lower ribs. However, the lower poles are inferior to the 12th ribs. The parenchyma of the kidney has a segmental arterial supply. This anatomic arrangement becomes important in the management of renal lacerations. Blunt injuries tend to fracture along the planes between the segmental vessels, while penetrating injuries cross the segmental vessels. Numerous anatomic variations exist, including pelvic kidneys; horseshoe kidneys; and multiple renal arterial, venous, and ureteral duplications. CONTRAINDICATIONSSection 5 of 11
For all practical purposes, no specific contraindications exist for surgical exploration of possible renal trauma. However, the general trend is toward a more selective approach. WORKUPSection 6 of 11
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Diagnostic Procedures
TREATMENTSection 7 of 11
Medical therapyNonoperative treatment In the setting of blunt renal trauma and selected instances of penetrating renal trauma, a nonoperative approach may be selected. Patient selection is the preliminary step in adopting a nonoperative management strategy to renal trauma. One series, with predominantly blunt mechanisms of injury, documented that 85% of patients were treated successfully without surgery. Ultimately, the exclusion of concurrent injury may be the key point in treating patients nonoperatively. The anatomic structure of the kidney lends itself to nonoperative management in the setting of blunt trauma. The kidney has an end artery blood supply with a segmental pattern of division that supplies the renal parenchyma. When subjected to blunt force that causes a laceration, the laceration tends to occur through the parenchyma. The resulting hematoma may displace renal tissue, but the segmental vessels themselves often are not lacerated. The closed retroperitoneal space around the kidney also promotes tamponade of bleeding renal injuries. Finally, the kidney is rich in tissue factor, the molecule that activates the extrinsic coagulation cascade, further promoting hemostasis after injury. Interventional radiology has extended the ability to use a nonoperative approach. Percutaneous drainage of perinephric fluid collections or urinomas has been used to address one clinical complication of a nonoperative approach. In addition, angiography with selective embolization has been used in the setting of isolated renal trauma. Another method to enhance a nonoperative approach includes endourologic stenting. With these approaches, successful nonoperative management of renal lacerations may be achieved in a greater number of patients. Surgical therapyOperative treatment The goals of operative therapy for renal laceration incorporate the 2 basic principles of hemorrhage control and renal tissue preservation, which must be balanced for each individual patient. Attempts to find a universal plan for this approach have generated controversy in the medical literature. The mindset of the medical community has also been changing as established practice patterns have been examined, challenged, and reassessed. An additional benefit of operative therapy is the ability to address concurrent injuries. One study documented that 80% of patients with renal laceration had other associated injuries. In that same study, 47% of the patients with renal laceration had an associated injury that required immediate laparotomy. At the time of the emergent laparotomy, the associated injury may be addressed. Evaluation and treatment of the renal injury is also possible. Patients with expanding hematomas or active hemorrhage should have their kidneys explored. Also, if the mechanism is penetrating trauma, most authors believe that the kidneys should be explored. Patients with sound indications for emergent exploration include those with hemodynamic instability or missile injury to the abdomen. Unrelenting gross hematuria may require urgent exploration. Operative technique can play a significant role in renal salvage. One study documented a decrease in the nephrectomy rate from 56% to 18% when a systematic approach was used for central control of the renal vessels at their junction with the aorta and cava. In this manner, vascular control is obtained outside of the Gerota fascia prior to entry into the zone of injury. Without both the arterial and venous systems isolated, the decompression of the renal hematoma that occurs during exploration tends to lead to a higher incidence of nephrectomy. Some controversy remains with the use of postoperative drains in the setting of renal trauma. The general trend has been away from the routine use of drains in this setting, although some centers still advocate their use. Suction drains should be avoided after renal repair. Preoperative detailsPatients with renal injuries should be managed with initial attention to the basic ABCDEs outlined in Advanced Trauma Life Support protocols. Because many patients have multisystem trauma with concurrent injuries, a systematic approach to the initial assessment and resuscitation allows for identification of other injuries. The decision-making process becomes more involved as additional injuries are found. For additional details, see Critical Care Considerations in Trauma or Initial Evaluation of the Trauma Patient (or other organ system–specific eMedicine trauma articles). Intraoperative detailsSurgical techniques
Postoperative detailsAs with all trauma patients, the postoperative course should be monitored to ensure successful hemostasis. Serial hematocrit measurements should be considered. In patients in whom a damaged but perfused kidney is left in situ, renovascular hypertension remains a theoretical possibility and the patient should be monitored clinically for this entity. Follow-upFor excellent patient education resources, visit eMedicine's Kidneys and Urinary System Center. Also, see eMedicine's patient education articles Intravenous Pyelogram and Blood in the Urine. COMPLICATIONSSection 8 of 11
Perioperative complications may be specific to the kidney or more generalized. Those specific to the kidney may include urinoma, hematoma, or infection. General complications may include deep vein thrombosis, systemic inflammatory response syndrome, or acute renal insufficiency. OUTCOME AND PROGNOSISSection 9 of 11
In many cases of renal trauma, the outcome and prognosis depend on the associated injuries. In situations in which nonoperative management is used, concern exists about leaving perfused but nonviable renal tissue in situ, which may lead to hypertension. However, the occurrence of hypertension in this setting seems to be rare. One study documents no evidence of hypertension after 5 years of follow-up in children who had sustained renal trauma. Other series report only isolated instances of hypertension. Therefore, the risk of hypertension alone does not seem to warrant surgical exploration in cases with nonperfused renal segments. FUTURE AND CONTROVERSIESSection 10 of 11
ControversiesPreoperative IVP for penetrating trauma Proponents of the one-shot IVP point out that it can be performed as the patient is being prepared for surgery and that it allows a quick assessment of the functionality of the contralateral kidney. Opponents believe that preservation of renal tissue is always a goal as long as the approach is safe for the patient. Knowledge of the functional status of the contralateral kidney does not change whether or not trying to salvage the kidney is safe. The timing of the injection may yield suboptimal views, and often, more time is needed to obtain images than is anticipated. The consensus on this technique remains incomplete. Intraoperative IVP can potentially allow leaving a perinephric hematoma unexplored if the study shows findings of a completely normal system. Some practitioners make extra efforts to succeed with operative salvage of a damaged kidney if the contralateral kidney is known to be absent. Operative technique (central vascular control) Proponents believe that data demonstrate enhanced renal salvage when vascular control is obtained outside the Gerota fascia. This technique allows controlled assessment of the nature of the renal laceration, and it may impart less trauma on the vessels compared to more urgent control measures. Opponents believe that not all renal injuries have sufficient bleeding to warrant central control of vessels. The technique requires some operative time and exposes the renal vessels to potential operative trauma. Anatomic variants, such as multiple arteries or veins, may not be recognized and may elicit a false sense of security. Hypertension Although concern exists that leaving perfused but nonviable renal tissue in situ potentially leads to hypertension, the occurrence of hypertension in this setting seems to be rare. One study documents no evidence of hypertension after 5 years of follow-up in children who had sustained renal trauma. Other series report only isolated instances of hypertension. Therefore, the risk of hypertension alone does not seem to warrant surgical exploration in cases with nonperfused renal segments. Nonperfused kidney Controversy exists regarding whether to revascularize a nonperfused kidney. The incidence rate of renal salvage in the setting of a nonperfused kidney due to trauma has been reported to be approximately 0%. Isolated case reports of success do exist. Most centers advocate an expectant management approach. The need for ultimate nephrectomy also remains somewhat controversial. Possible or documented renovascular injury continues to be a controversial arena of renal injury management. Only aggressive intervention provides the opportunity for renal salvage. However, the clinician must be aware that the salvage rate is low, and, ultimately, the life of the patient must take priority over the life of the kidney. Continued investigation and evolution of surgical techniques may help resolve this controversy. ConclusionThe approach to the diagnosis and management of renal trauma continues to evolve. In the setting of significant hemodynamic instability, operative exploration remains the diagnostic and therapeutic modality of choice. In patients with blunt trauma and in certain cases of penetrating trauma, a progressive trend is towards nonoperative management of renal trauma. Continued change in the approach to renal trauma is almost a certainty. Interventional radiology and endourologic manipulation have increased the ability to successfully treat patients without surgery and to address common complications of renal trauma. Numerous diagnostic options exist in the setting of a stable patient. With awareness of these modalities, the clinician can provide each patient with optimal treatment. REFERENCESSection 11 of 11
Article Last Updated: Jun 12, 2006 |
