This chapter will cover the operative management of renal injuries encountered during the care of combat trauma casualties. Renal injuries may seem daunting to the elective general surgeon not accustomed to operating in the retroperitoneum or on the genitourinary system, but they are relatively easy to manage in the acute setting. However, a basic understanding of management of renal injuries is essential for the combat surgeon as the kidney may be injured by any mechanism, particularly in the setting of penetrating or blast injury. You are highly unlikely to have a urologist or transplant Surgeon immediately available to assist you, but you can expertly manage renal trauma without them. This chapter will review indications for operation and renal exploration, operative exposure and injury evaluation, repair and resection (partial and nephrectomy ) of the injured kidney, and postoperative complications.

The patient with a renal injury is rarely obvious at initial presentation. The casualty will present with abdominal trauma, either blunt or penetrating, and you must efficiently sort out whether this casualty needs an emergent laparotomy or merits further evaluation. However, like all combat casualties, hemodynamic stability is the driving force behind indications for operation. A hemodynamically unstable casualty with penetrating abdominal trauma mandates emergent exploratory laparotomy. Similarly, a hemodynamically unstable casualty who has sustained blunt or blast injury requires emergent laparotomy if the instability is attributable to the abdomen (positive focused assessment with sonography for trauma [FAST exam] or diagnostic peritoneal aspirate [DPA ]). The retroperitoneum is not easily evaluated by FAST or DPA , however. Thus, a casualty with blunt or blast injury in whom other sources of hypotension have been ruled out and instability persists may require a laparotomy to definitively rule out an intra-abdominal or retroperitoneal source of hemorrhage.

In casualties with abdominal trauma and hemodynamic instability who are taken directly to the operating room, the presence of a renal injury will be discovered at the time of laparotomy. However, if you place a urinary catheter and see gross hematuria, then your index of suspicion for a genitourinary injury is obviously heightened. Your most likely diagnosis will be a bladder injury, but you must always assume the possibility of a major renal injury. Conversely, do not depend on gross hematuria as a clue – normal appearing urine is a common finding with even high-grade renal lacerations. Like any casualty requiring laparotomy, those with a suspected renal injury should be in the supine position with both arms abducted, prepped, and draped widely (chin to mid-thigh, table-to-table), and you should access the abdomen via a generous midline laparotomy from xiphoid to pubis. Upon entering the abdomen, you should proceed as with any casualty with intra-abdominal injury: evacuate hemoperitoneum, stop the bleeding, control contamination, and repair injuries. A renal injury will be suspected by the presence of a zone II (lateral to the midline) retroperitoneal hematoma. However, you should address any intraperitoneal hemorrhage before attacking a renal injury, as Gerota’s fascia and the retroperitoneum provide tamponade for most renal hemorrhage. If the hematoma has ruptured or is actively bleeding through a hole in Gerota’s fascia, it can usually be controlled by direct pressure with a lap sponge or hemostatic packing.

Once you have addressed the intraperitoneal bleeding, you can turn your attention to the lateral retroperitoneum. You should explore the retroperitoneum in any hemodynamically unstable casualty with a zone II hematoma, whether from blunt or penetrating trauma or those who will undergo evacuation. You do not want something that might unleash during flight. After blunt trauma, you may choose to observe hemodynamically stable casualties with a zone II hematoma as long as the hematoma is not pulsatile and not expanding during a period of observation. If you choose not to explore a zone II hematoma, that casualty will require postoperative imaging with a CT scan to fully determine the extent of renal injury. In general, you should explore all zone II retroperitoneal hematomas secondary to penetrating trauma. However, you may consider not exploring the retroperitoneum if the hematoma lies in the lateral portion of zone II (Fig. 10.1), away from renal hilar structures (artery, vein, ureter, renal calyx). This approach should be reserved for very select cases and only considered in hemodynamically stable casualties. Always have a clear idea of what you are looking for or expecting with retroperitoneal hematomas. A zone II hematoma is assumed to be either due to an injury to the renal vascular pedicle or to the renal parenchyma. If the hematoma is lateral to the renal hilum, then you can assume it represents a parenchymal injury which we know can usually be managed without surgical intervention. However, in the combat scenario, you must also consider your ability to closely observe the patient postoperatively and how soon he will be placed into the evacuation chain.

In casualties with suspected intra-abdominal injury that present and remain hemodynamically stable, the presence of a renal injury will usually be discovered at the time of CT scan of the abdomen. CT scan is the definitive imaging used to evaluate renal injuries and if available obviates the need for any other diagnostic tests such as an intravenous pyelogram (IVP) . You can use the CT scan to grade renal injuries according to the American Association for the Surgery of Trauma organ injury severity scale for renal trauma (Table 10.1). You can use the grade of injury seen on CT scan to determine need for operative management of the renal injury. In general, you may manage grade I and II injuries non-operatively and most will heal without consequence. You can also treat grade III and IV lacerations without operation. However, if other intraperitoneal injuries seen on CT scan require operative intervention, you should explore the grade III/IV laceration at the time of laparotomy. If you discover a renal vascular injury (grade IV or V) or a grade V laceration (shattered kidney) on CT scan, you should take the casualty for laparotomy and renal exploration. You usually will not have access to advanced interventional radiologic support or even adjuncts such as cystoscopy and stent placement. Take this into consideration when applying the civilian paradigm of nonoperative management of these injuries.

During the initial laparotomy, your exposure to the kidney will be greatly facilitated by placing a self-retaining retractor such as a Balfour or preferably a Bookwalter. Surgical equipment may vary significantly depending on your unit and supply chain (particularly in a far-forward detachment), so I encourage you to open your surgical instruments and retractors to familiarize yourself before your first operation. Prior to exposing either kidney in an attempt to repair, or particularly if you expect to perform a nephrectomy , you should palpate the contralateral kidney. If you feel a normal kidney on the unaffected side, you can feel comfortable in performing a nephrectomy on the injured side if needed, without fear of making the casualty dialysis-dependent. In the unusual case that you palpate an abnormal kidney (absent, atrophic, polycystic) on the unaffected side, you may consider performing an on-table IVP to determine if the abnormal kidney is functional. However, trying to routinely perform an on-table IVP in order to evaluate the function of the uninjured kidney is unnecessary, technically difficult, often inadequate, and most importantly time-consuming. Ditto for the oft-touted “one-shot IVP” in the emergency department for penetrating trauma patients. Don’t waste time and effort on these mostly useless studies, especially down range.

Once you have palpated a normal contralateral kidney and are ready to approach the injured side, you may use one of two approaches for exposure of the kidneys. You may either (1) obtain initial renal vascular control followed by renal exploration or (2) initially explore the kidney and obtain renal vascular control after complete mobilization of the kidney. Both approaches have pros and cons and should be individualized based on the casualty and the surgeon’s experience and expertise. In general, the first approach is preferable in a stable patient without ongoing hemorrhage, and the second approach is preferred when time is of the essence. Obtaining initial vascular control has the benefit of securing definitive vascular control prior to exposing the injured kidney, allowing you to secure inflow and outflow if exsanguinating hemorrhage is encountered from the kidney. Figures 10.2 and 10.3 demonstrate the maneuvers and anatomy to obtain renal vascular control. However, there are several downsides to obtaining vascular control prior to renal exposure. First, a small minority of renal injuries will require vascular control prior to repair, making this maneuver unnecessary in most cases. Second, obtaining vascular control in the midline can be technically challenging, particularly in the setting of a large retroperitoneal hematoma and for the surgeon inexperienced in vascular or urological surgery. Finally and most importantly, obtaining initial vascular control is definitely time consuming, even in experienced hands, and can delay definitive renal repair or a potentially lifesaving nephrectomy . For these reasons, while managing renal injuries in the setting of combat surgery, you should first efficiently expose the injured kidney and then obtain vascular control of the renal pedicle if necessary (Fig. 10.4).