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Renal Trauma: Injury of the Kidney
Review literature: (Diederichs and Mutze, 2003) (Kawashima et al, 2002) (Meria and Mazeman, 2000) (Vasile et al, 2000).
Etiology of Injuries of the Upper Urinary Tract
Gunshot or stab wounds.
Direct blunt force (contusion, bruising of the abdomen or flank) leads to a rupture the kidneys. Deceleration in high-velocity accidents (falls from height oder motor vehicle accidents) damage the kidney, renal vessels or ureter by the inertia of the mass.
Epidemiology of renal trauma:
- In blunt abdominal trauma, up to 40% present with renal injury.
- In urban areas, 80% of renal injuries occur in the context of polytrauma.
- In ski resorts, 2/3 of renal injuries are due to skiing accidents.
- Children tend to have higher grade injuries, as well as patients with anomalies of the upper urinary tract.
- Penetrating injuries (gunshot or stab wounds) are rare, they play a greater role in the U.S. than in Europe.
Signs and Symptoms of Renal Trauma
Acute signs and symptoms:
- History of abdominal trauma or deceleration injury
- Bruising and hematoma of abdomen or flank
- Abdominal tenderness and tumor
- Flank pain
- Rib fracture
- Hemodynamic instability, Shock
Late complications of renal trauma:
- Renal Abscess
- Renal arteriovenous fistula
- Renal hypertension
- Loss of renal function
Diagnostic Work-up of Renal Trauma
Urine sediment, blood count, creatinine. The lack of hematuria does not exclude severe renal trauma.
Abdominal (renal) ultrasound may be a valuable tool for initial evaluation of abdominal injuries to reveal free abdominal fluid, retroperitoneal hematoma, urinoma and hydronephrosis. Doppler ultrasound may be helpful to demonstrate renal pedicle injury or kidney infarction.
CT is the imaging technique of choice, if there is a high suspicion for renal injury: severe trauma, abnormalities in ultrasound imaging or hematuria. To exclude bladder injury in blunt abdominal trauma, the bladder should be filled with diluted contrast media before CT. [fig. CT imaging of renal trauma]. Contraindication of CT: patients with unstable circulation after initial resuscitation require surgical intervention without further imaging.
The investigation is largely replaced by computed tomography. IVP may be indicated (as an alternative to CT) to exclude renal injury, e.g. with hematuria and normal ultrasound imaging, and if CT is not available. Urography has also a limited role in intraoperative imaging (single shot IVP).
Classification (Severity) Of Renal Trauma
Classification of the American Association for the Surgery of Trauma:
Renal contusion with hematuria or subcapsular hematoma.
Renal laceration of less than 1 cm, perirenal hematoma confined to the retroperitoneum.
Renal laceration of more than 1 cm, without urinary extravasation, perirenal hematoma confined to the retroperitoneum.
Renal laceration extending through renal cortex, medulla and collection system with urinary extravasation. Renal artery or renal vein injury with contained hemorrhage (and partial devascularization of the kidney).
Completely shattered kidney. Avulsion of the renal hilum. Devascularization of the complete kidney.
Treatment of Renal Trauma
Conservative management is possible in renal trauma with stable circulation and trauma severity grade I–III (no urinary extravasation). Important is bed rest until gross hematuria resolves and frequent monitoring of vital signs and blood count. Fever, dropping blood count or flank pain are indications for repeated imaging (ultrasonography or CT).
Internal ureteral stent:
Ureteral stenting is indicated for urinary extravasation in grade IV renal injury (MJ/DJ ureteral stent or percutaneous nephrostomy). Large (delayed diagnosed) urinomas are drained percutaneously. Antibiotic prophylaxis is often recommended.
Absolute indications for operative management are:
- Hemodynamic instability after initial resuscitation
- Grade V renal injury with expanding renal hematoma
- Ureteropelvic junction disruption
Relative indications for operative management are:
- Urinary extravasation with nonviable renal tissue over 25%
- Associated intraabdominal injuries
- Gunshot wounds
- Suspicious intraoperative IVP, if laparotomy was necessary without preoperative imaging.
Transperitoneal exposure using a midline laparotomy, cell saver and packed red blood cells for transfusion should be ready. Early vascular control before opening of Gerota's fascia improves renal salvage rate. Renal reconstruction can be done with temporary ischemia. Kidney defects may be sutured (renorrhaphy) and covered with omentum majus, absorbable mesh or retroperitoneal fat. Hemostatic agents are helpful in controlling the bleeding tissue. If necessary, urinary drainage is done via nephrostomy.
Indications for nephrectomy: extensive renal or vascular injury, unstable patient.
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- Diederichs und Mutze 2003 DIEDERICHS, W. ; MUTZE, S.:
- [Renal trauma: is open surgery still up to date?].
In: Urologe A
42 (2003), Nr. 3, S. 322–7
- Kawashima u.a. 2002 KAWASHIMA, A. ; SANDLER, C. M. ; CORL, F. M. ; WEST, O. C. ; TAMM, E. P. ; FISHMAN, E. K. ; GOLDMAN, S. M.:
- Imaging evaluation of posttraumatic renal injuries.
In: Abdom Imaging
27 (2002), Nr. 2, S. 199–213
- Meria und Mazeman 2000 MERIA, P. ; MAZEMAN, E.:
- Immediate and delayed management of renal trauma.
In: Eur Urol
37 (2000), Nr. 1, S. 121–30
- Vasile u.a. 2000 VASILE, M. ; BELLIN, M. F. ; HELENON, O. ; MOUREY, I. ; CLUZEL, P.:
- Imaging evaluation of renal trauma.
In: Abdom Imaging
25 (2000), Nr. 4, S. 424–30
Deutsche Version: Nierentrauma