Ureteroinguinal Hernia: a Rare Cause of Ureteral Obstruction

May 25, 2007
Surgical Rounds®, March 2006, Volume 0, Issue 0

Michelle Elizabeth Brand, Resident, Physical Medicine and Rehabilitation, U; Steven Brooks, ; Robert M. Esterl, Jr., Professor of Surgery,

Michelle Elizabeth Brand, MD

Resident Physical Medicine and Rehabilitation University of Texas Health Science Center at San Antonio San Antonio, TX

Steven Brooks, CST, CFA

Operating Room Technician Brownsville Medical Center Brownsville, TX

Karen Brooks-Searle, MD

Clinical Assistant Professor Department of Surgery University of Texas Health Science Center at San Antonio San Antonio, TX

Robert M. Esterl, Jr., MD

Professor of Surgery Transplant Center University of Texas Health Science Center at San Antonio San Antonio, TX

Ureteroinguinal hernias are rare, with about 130 cases re?ported in the world literature. The current classification divides ure?teroinguinal hernias into paraperitoneal and extraperitoneal subtypes, depending on the distinct inguinal anatomy. We report a unique case of a ureteral obstruction caused by an ureteroinguinal hernia that did not fit clearly into either classification. We also review the pathophysiology, diagnosis, and treatment of ure?teroin?guinal hernias. Clinicians should consider the possibility that the ureter or other retroperitoneal structures may be included in the hernia contents. Height?ened awareness of this possibility will prevent iatrogenic injury to the ureter or the other structures when managing these rare inguinal hernias.

Case report

A 59-year-old Hispanic man presented with a painful rash on the right flank. He had a history of coronary artery disease, cerebrovascular disease, hypertension, diabetes mellitus, and a right inguinal hernia, which had been present for years.

His surgical history was significant for multiple partial cystectomies for bladder cancer and ventral incisional herniorrhaphy. The patient did not report nausea, vomiting, constipation, abdominal distension, or urinary symptoms. On physical examination, he had a vesicular rash along the distribution of the right ninth thoracic dermatome, which was consistent with shingles. He also had a large, poorly reducible right inguinal hernia.

The workup included a noncontrast computed tomography (CT) scan of the abdomen and pelvis, which showed a large, right, incarcerated, indirect inguinal hernia displacing the bladder (Figure 1). The hernia contained a large amount of fat and the distal right ureter (Figure 2). Moderate cortical atrophy and marked hydronephrosis were noted in the right kidney, but the left kidney was normal (Figure 3). A technetium-99m diethylen?e?triamine penta-acetic acid (DTPA) renal scan demonstrated decreased cortical function and obstruction of the right kidney and a normal functioning left kidney (Figure 4). The patient's serum and urinary chemistry values were normal.

A right inguinal herniorrhaphy was performed to relieve the suspected ureteral obstruction. A right inguinal in?cision was made and a massive hernia was identified. The testicle, cord structures, and hernia sac were elevated out of the scrotum into the wound. With meticulous dissection, the cord structures were separated from an indirect hernia sac. The hernia sac was opened and revealed no intra-abdominal contents or sliding components. Adjacent to the indirect hernia sac was a large amount of retroperitoneal fat, which contained a markedly dilated ureter (Figure 5). The retroperitoneal fat was ligated and excised, and the ureter was returned to its proper position in the retroperitoneum. The herniorrhaphy was performed with a mesh plug and patch. The patient's postoperative recovery was uneventful.

Discussion

Ureteral herniation is rare. In 2002, Hwang and colleagues reported on the 128 known documented cases of ureteral herniation.1 Ureteral herniation can occur at several sites: inguinal, femoral, sciatic, thoracic, and parailiac.1,2 Ureteral herniation typically presents as a mass in the groin without any urinary symptoms.3-5 In the report by Hwang and colleagues, 54 of 128 ureteral herniations (42%) were inguinoscrotal.1 Inguino?scrotal hernias are divided into two distinct anatomical types: paraperitoneal and extraperitoneal. Eighty percent of these hernias are paraperitoneal and 20% are extraperitoneal.

The paraperitoneal type contains a hernia sac anteromedially and the ureter posterolaterally. This type of hernia is almost always indirect and often sliding. They are usually found in men (94%) and on the right side (67%). The higher incidence on the right side is probably due to the sigmoid colon lying on the left side.2 Paraperitoneal hernias are acquired and usually present in the fourth to sixth decade of life, though one case of a paraperitoneal hernia has been reported in a 6-week-old male.6

In paraperitoneal hernias, the ureter gets pulled into the scrotum due to traction on underlying structures or from adhesions connecting the ureter to the posterior peritoneum.7 Because they are often sliding hernias, other abdominal organs (bladder, colon, and female genital organs) frequently make up the wall of the indirect hernia sac. Intra-abdominal organs can also be found in the in-direct hernia sac. On physical examination, the paraperitoneal hernia varies in size (though it is often large) and is usually reducible. Patients rarely report any symp?toms of urinary or bowel obstruction. Paraperitoneal hernias are rarely as?sociated with renal or ureteral anatomic malformations such as crossed renal ectopia, low-lying kidney with double ureter, multiple renal cysts, or bilateral megaureters.1,5,6

In contrast to paraperitoneal hernias, the less common extraperitoneal hernias usually contain the ureter as the sole organ. Extraperitoneal hernias are indirect, but typically no hernia sac is pres?ent. Retroperitoneal fat is frequently contained in the hernia, and the fat is often mistaken to be an indirect hernia sac. Extraperitoneal hernias are usually small on physical examination, are sometimes difficult to palpate, and are typically nonreducible. The age of onset is variable. Unlike paraperitoneal hernias, ex?traperitoneal hernias often cause urinary symptoms.5 The extraperitoneal type is congenitally acquired due to failure of the ureter to differentiate fully from the Wolffian duct.5 During testicular descent, the testis is guided into the scrotum by two genitoinguinal ligaments. The Wolf?fian duct connects these ligaments to the testes. During the third or fourth week of gestation, the Wolffian duct gives off a stalk that becomes the ureter. Therefore, if there is failure of ureteral differentiation, the ureter can easily be pulled along with the testis into the scrotum and herniate.1,6,8 Adhesions between the primitive ureter and the genitoinguinal ligaments can also drag the ureter into the hernia. Unlike paraperitoneal hernias, many extraperitoneal hernias (46%) have an associated congenital renal or ureteral anatomic malformation, of which cros?sed renal ectopia and nephroptosis are the most common.3,5,8

Our case is unique because the hernia did not clearly match either category. It fit the paraperitoneal type because the hernia was large, contained an indirect sac, and occurred in a middle-aged pa?tient. Unlike most paraperitoneal types, however, the indirect hernia sac in our patient did not have intra-abdominal organs or sliding components. This case also met some criteria of the extraperitoneal type because the hernia was nonreducible and only contained the ureter and retroperitoneal fat. Because the indirect hernia sac was clearly separate from the retroperitoneal fat, we can rule out the possibility that the abundant fat was mistaken for the sac.

It is difficult to determine the etiology for the ureteral herniation in our case because the type of inguinoscrotal hernia cannot be clearly defined. It is likely that previous bladder operations caused adhesions to develop between the ureter and the posterior peritoneum, and the development of an indirect inguinal hernia sac pulled the ureter into the scrotum. It is also possible that the multiple previous operations on the bladder and abdominal wall caused intra-abdominal adhesions that prevented herniation of the more common organs into the indirect hernia sac. Although unlikely, another possibility is that the ureteral herniation developed as a result of abnormal ureteral development; however, the patient had no previously documented congenital genitourinary malformation and no genitourinary symptoms.

The diagnosis of ureteral herniation in an inguinoscrotal hernia is commonly missed due to the lack of urinary symptoms. Standard herniorrhaphy can be dangerous if one does not suspect a ure?ter in the contents, and iatrogenic ureteral damage would likely result.3 If a hernia has an abundance of fatty tissue, it is important to have a heightened suspicion of the ureter being present in the hernia. A preoperative intravenous pyelogram is recommended only in patients with an inguinal hernia and urinary symptoms.2,4,5,8,9 A CT scan of the ab?domen can further clarify the presence of the ure?teral obstruction in a patient with an inguinoscrotal hernia and urinary symptoms.10 Surgical treatment usually in?volves replacing the ureter in the re?t?ro?peritoneum and repairing the hernia. If the herniated ureter is redundant or diseased, repair should include excision of the ureter followed by primary anastomosis or ureteroneocystostomy.3 A postoperative intravenous pyelogram should be performed to ensure patency and proper replacement of the ureter.2,3

Conclusion

Our case is unique because it has elements of both paraperitoneal and ex?traperitoneal ureteroinguinal hernias. The diagnosis of ureteral herniation in an inguinoscrotal hernia is commonly overlooked because of the lack of urinary symptoms in most patients. Standard herniorrhaphy can be dangerous if one does not suspect a ureter in the hernia. Therefore, if there is an abundance of fatty tissue in a hernia, it is important to have a heightened suspicion for the presence of a ureter in the hernia. A preoperative intravenous pyelogram and CT scan of the abdomen and pelvis can further clarify the existence of ureteral obstruction in an inguinoscrotal hernia in a patient who has urinary symptoms. Surgical treatment usually involves re?placing the ureter in the retroperitoneum and repairing the hernia.

References

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