RENAL TRAUMA TREATMENT

Renal trauma: treatment
Conservative (non-operative) management
Most blunt (95%) and many penetrating renal injuries (50% of stab injuries and 25% of gunshot wounds) can be managed non-operatively.
Dipstick or microscopic haematuria: if systolic BP since injury has always been >90mmHg and no history of acceleration or deceleration, imaging and admission is not required.
Macroscopic haematuria: in a cardiovascularly stable patient, having staged the injury with CT, admit for bed rest and observation, until the macroscopic haematuria, if present, resolves (cross-match in case blood pressure drops). High-grade (IV and V) injuries can be managed non-operatively if they are cardiovascularly stable. However, grade IV and, especially, grade V injuries often require nephrectomy to control bleeding (grade V injuries function poorly if repaired).

Surgical exploration
Is indicated (whether blunt or penetrating injury) if:
- the patient develops shock which does not respond to resuscitation with fluids and/or blood transfusion
- the haemoglobin decreases (there are no strict definitions of what represents a  significant  fall in haemoglobin)
- there is urinary extravasation and associated bowel or pancreatic injury
expanding peri-renal haematoma (again the patient will show signs of continued bleeding)
- pulsatile peri-renal haematoma
An expanding and/or pulsatile peri-renal haematoma suggests a renal pedicle avulsion. Haematuria is absent in 20%.

Urinary extravasation
Not in itself necessarily an indication for exploration. Almost 80 90% of these injuries will heal spontaneously. The threshold for operative repair is lower with associated bowel or pancreatic injury bowel contents mixing with urine is a recipe for overwhelming sepsis. In these situations the renal repair should be well drained and omentum interposed between the kidney and bowel or pancreas.
If there is substantial contrast extravasation, consider placing a JJ stent. Repeat renal imaging if the patient develops a prolonged ileus or a fever, since these signs may indicate the development of a urinoma which can be drained percutaneously. Renal exploration is required for a persistent leak.

Devitalized segments
Exploration is usually not required for patients with devitalized segments of kidney and with urinary extravasation.

Hypertension and renal injury
Excess renin excretion occurs following renal ischaemia from renal artery injury or thrombosis or renal compression by haematoma or fibrosis. This can lead to hypertension months or years after renal injury. The exact incidence of post-traumatic hypertension is uncertain. It may occur in <1% of individuals.

Technique of renal exploration
Midline incision allows:
- exposure of renal pedicle, so allowing early control of the renal artery and vein, and
- inspection for injury to other organs.

Lift the small bowel upwards to allow access to the retroperitoneum. Incise the peritoneum over the aorta, above the inferior mesenteric artery. A large peri-renal haematoma may obscure the correct site for this incision. If this is the case, look for the inferior mesenteric vein and make your incision medial to this. Once on the aorta, the inferior vena cava may be exposed, then the renal veins and the renal arteries. Pass slings around all of these vessels. Expose the kidney by lifting the colon off of the retroperitoneum. Bleeding may be reduced by applying pressure to the vessels via the slings. Control bleeding vessels within the kidney with 4/0 vicryl or monocryl sutures. Close any defects in the collecting system with 4/0 vicryl. If your sutures cut out, place a strip of Surgicel over the site of bleeding, place your sutures through the capsule on either side of this, and tie them over the Surgicel. This will stop them from cutting through the friable renal parenchyma.

Finding a non-expanding, non-pulsatile retroperitoneal haematoma at laparotomy
The finding of an expanding and/or pulsatile retroperitoneal haematoma at laparotomy will often indicate a renal pedicle injury (avulsion or laceration), and nephrectomy may be required to stop further haemorrhage.

Controversy surrounds the correct management of the finding at laparotomy of a non-expanding, non-pulsatile retroperitoneal haematoma. Most can be left alone. Remember, exploration increases the chances of loss of the kidney (because of bleeding which can be controlled only by nephrectomy).