Материал: Oxford American Handbook of Urology ( PDFDrive )

URETER INNERVATION 417

Ureter innervation

Autonomic

The ureter has a rich autonomic innervation.

•Sympathetic—preganglionic fibers from spinal segments T10 to L2; postganglionic fibers arise from the celiac, aorticorenal, mesenteric, superior and inferior hypogastric (pelvic) autonomic plexuses

•Parasympathetic—vagal fibers via celiac to upper ureter; fibers from S2–4 to lower ureter

The role of ureteric autonomic innervation is unclear. It is not required for ureteric peristalsis (though it may modulate this). Peristaltic waves originate from intrinsic smooth muscle pacemakers located in minor calyces of renal collecting system.

Afferent

•Upper ureter—afferents pass (alongside sympathetic nerves) to T10–L2

•Lower ureter—afferents pass (alongside sympathetic nerves and by way of pelvic plexus) to S2–4.

Afferents subserve stretch sensation from the renal capsule, collecting system of kidney (renal pelvis and calyces), and ureter. Stimulation of the mucosa of the renal pelvis, calyces, and ureter also stimulates nociceptors, the pain felt being referred in a somatic distribution to T8–L2 (kidney T8–L1, ureter T10–L2), in the distribution of the subcostal, iliohypogastric, ileoinguinal, or genitofemoral nerves.

Thus, ureteric pain can be felt in the flank, groin, scrotum or labia, and upper thigh, depending on the precise site in the ureter from which the pain arises.

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420 CHAPTER 10 Trauma to the urinary tract

Renal trauma: classification and grading

Classification

There are two categories of renal trauma—blunt and penetrating. At least 90% of renal injuries in the United States occur from blunt trauma, and most of these are trivial in nature (either superficial lacerations or contusions).

The mechanism of injury is important to consider because it predicts the likely need for surgical exploration to control bleeding. Experience from large series shows that 95% of blunt injuries can be managed conservatively. Penetrating renal injuries tend to be of greater severity; thus, roughly 50% of stab injuries and 75% of gunshot wounds require surgical exploration.

Blunt injures

•Direct blow to the kidney

•Rapid deceleration

A direct blow from a fall, assault, or sports injury is often associated with renal laceration. Rapid-deceleration injuries usually occur as a result of motor vehicle collisions. Because the renal pedicle is the site of attachment of kidney to other fixed retroperitoneal structures, renal vascular injuries (tears or thrombosis) or UPJ disruption may occur.

Penetrating injuries

Stab or gunshot injuries to the flank, lower chest, and anterior abdominal area may inflict renal damage; half of patients with penetrating trauma and hematuria have grade III, IV, or V renal injuries.

Penetrating injuries anterior to the anterior axillary line are more likely to injure the renal vessels and renal pelvis than are injuries posterior to this line, where less serious parenchymal injuries are more likely. Thus, renal injuries from stab wounds to the flank (i.e., posterior to anterior axillary line) can often be managed nonoperatively.

Wound profile of a low-velocity gunshot wound is similar to that of a stab wound. High-velocity gunshot wounds (>350 m/s) cause greater tissue damage due to a cavitation effect, which produces stretching and disruption of surrounding tissues.

Mechanism

Because the kidneys are retroperitoneal structures surrounded by perirenal fat, the vertebral column and spinal muscles, the lower ribs, and abdominal contents, they are relatively well protected from injury and a considerable degree of force is usually required to injure them—only 1.5–3% of trauma patients have renal injuries. Associated injuries are therefore common (e.g., spleen, liver, mesentery of bowel).

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