patients with symptomatic sciatic hernias commonly present with flank , abdominal , pelvic , lower back or thigh pain .
most asymptomatic patients have been treated conservatively , while surgery has been reserved for symptomatic patients .
we describe a case revealed by left hydronephrosis with severe left back pain in a 72-year - old female .
this case shows that minimally invasive endourological techniques may provide a novel method for relieving this cause of obstruction .
a 72-year - old female accidentally struck her left forechest 2 months before she was referred to our hospital , and lower left rib fracture was observed on x - ray examination .
she was suffering from severe left - sided back pain , which was thought to be apart from the rib fracture site , and the pain was intermittent .
the ultrasound sonography demonstrated left hydronephrosis and a simple renal cyst on the lower pole of the left kidney , and urinalysis showed microhematuria .
routine blood tests were not remarkable except for a slightly elevated serum glucose level of 179 mg / dl .
intravenous ureterography ( ivu ) showed findings compatible with a left sciatic ureter , a dilated ureter with a fixed kinking , which is known as 
the abdominal ct showed marked hydronephrosis and hydroureter on the level of the pelvic inlet and revealed the presence of a sciatic herniation of the ureter ( fig .
2 ) . the ureter was seen to course behind the left hip and through the greater sciatic foramen , anterior to the piriformis muscle .
no evidence of inflammatory lesions , compressive tumor or herniation of another pelvic organ with the ureter was seen .
subsequently , the placement of ureteral stent was performed to decompress the dilated upper urinary tract .
interestingly , the ureterosciatic hernia was relieved with the passage of a flexible guide wire and a double - pigtail stent ( fig .
however , the patient refused continuing to have an indwelling stent and the stent was removed .
ivu obtained 3 months after the removal of the ureteral stent revealed the recurrence of the ureterosciatic hernia ; however , there was no evident recurrence of hydroureter , hydronephrosis or ureteral obstruction . since then
six years after ureteral stenting , the patient continues to be without hydronephrosis , symptoms or the usage of the indwelling ureteral stent .
most ureteral herniations occur in the inguinal area but they have also been noted in femoral , sciatic , thoracic , and parailiac locations . among them , ureterosciatic herniation is extremely uncommon ; only 31 cases have been reported since 1947 [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ] . the clinical symptoms are nonspecific , consisting of ill - defined abdominal pain .
patients may have nonurologic complaints including vague abdominal pain or symptoms more typical of small - bowel obstruction . when obstructive uropathy develops , patients with ureterosciatic hernias may or may not experience symptoms of renal colic .
the diagnosis is difficult to establish by physical examination because ureterosciatic hernias are deep to the gluteal muscles .
however , these hernias may be detected as a palpable mass located underneath the gluteal muscles in a thin patient [ 4 , 9 ] .
anatomically , most ureteral herniations such as ureteroinguinal and ureterofemoral hernias are paraperitoneal , since they are adherent to the posterior parietal peritoneum and hence associated with a herniating peritoneal sac . in contrast , ureterosciatic hernias are always extraperitoneal .
structures such as small intestine , meckel 's diverticulum , omentum , colon , ovary , fallopian tube , bladder , and ureter may be found in sciatic hernia sacs [ 3 , 4 , 5 , 6 ] . in ureterosciatic
herniation , prolapse of the ureter occurs through the sciatic notch , which is divided by the sacrospinous ligament into the greater and lesser sciatic foramina .
the greater sciatic foramen is considered a potential space , as the piriformis muscle completely occupies the greater sciatic foramen .
the greater sciatic foramen is bound by the ilium laterally , the sacrum and sacrotuberous ligament medially , and the sacrospinous ligament inferiorly .
the greater sciatic foramen is further subdivided into the suprapiriformis and infrapiriformis compartments by the piriformis muscle .
ureterosciatic herniations usually occur through the suprapiriformis compartment of the greater sciatic foramen [ 5 , 10 ] .
previous reports have suggested that atrophy of the piriformis muscle is the predisposing factor for the development of ureterosciatic herniation , creating a potential space through which the ureter could migrate .
it has been speculated that the main predisposing factor could be piriformis muscle atrophy , related to hip joint disease , neuromuscular disorders or other locomotor disturbances of the lower extremities [ 4 , 5 , 6 , 7 , 9 ] .
although most hernias occur through the greater sciatic foramen , several ones have been reported to herniate through the lesser sciatic foramen [ 2 , 5 , 8 , 9 ] .
these cases are usually undiagnosed clinically because the gluteus maximus muscle overlies the sciatic foramen .
sciatic ureter has a characteristic radiologic appearance in which a loop of ureter is displaced laterally , inferiorly , and posteriorly through the sciatic notch on ivu and retrograde urography .
the diagnosis was confirmed by this image , known as the  curlicue sign , which is considered pathognomonic for ureterosciatic herniation .
ct may be helpful in diagnosis with the appearance of an ectopically positioned ureter posterior and lateral to the ischial spine , it can demonstrate an ureter with more anatomic information , and it may be useful in detecting the involvement of other structures [ 6 , 12 ]
. moreover , ct with three - dimensional reconstruction might be useful for defining the exact location and extent of the herniation .
in previous reports , treatments for symptomatic patients included relief of the hernia by excision and reimplantation , ureteroureterostomy or stent placement and observation [ 2 , 8 ] . in our patient , conservative endourological correction was performed . after the spontaneous removal of the ureteral stent , recurrent ureterosciatic hernia occurred .
placement of an internal stent possibly provides the rigidity to the ureter , thereby recovering the hernia and urinary obstruction .
observation should be used judiciously because the consequences of long - term obstruction can be devastating .
indeed , ureterosciatic hernia causing intermittent ureteral obstruction and producing significant morbidity should be repaired .
furthermore , when the ureter shows signs of inflammation or trophic disturbances , ureterolysis , reimplantation , and hernioplasty should be carried out [ 1 , 2 , 3 , 4 , 8 , 10 ] .
surgical options include excision of the hernia with reimplantation of the remaining ureter , reduction of the ureter length , and transabdominal or transgluteal surgical reduction of the hernia plus fixation of the ureter [ 2 , 4 , 8 ] .
recently , laparoscopic and robotic repair surgery has also been reported [ 10 , 15 ] .
however , surgical repair should not be performed in asymptomatic patients . for the patient who is elderly or a poor surgical candidate
sugimoto et al .   also reported a case successfully treated by ureteral stent placement .
it is advisable to place a stent for few months and then remove it to see whether the obstruction recurs .
this approach provides a minimally invasive means for the treatment of what can be a devastating problem .
 ureterosciatic herniation , the protrusion of the hernia sac through the sciatic foramen , is an extremely rare cause of ureteral obstruction . 
 we describe a case revealed by severe left back pain in a 72-year - old female . 
 she was referred to our hospital for urological assessment of left hydronephrosis observed by ultrasonography . 
 intravenous ureterography ( ivu ) showed findings compatible with a left sciatic ureter , a dilated ureter with a fixed kinking , which is known as the  curlicue sign . 
 we decided to attempt recovery of the herniated ureter using a retrograde approach . 
 ureteral stent placement was performed to decompress the dilated upper urinary tract . 
 the ureterosciatic hernia was relieved with the passage of a flexible guide wire and a double - pigtail stent . 
 three months after ureteral stenting , she refused continuing to have an indwelling stent and the stent was removed . 
 thereafter , ivu revealed recurrent ureterosciatic hernia ; however , there was no hydroureter or hydronephrosis . 
 the patient is currently being under observation for 6 years after stenting and continues to be without hydronephrosis or symptoms . 
 placement of an internal stent possibly provides the rigidity to the ureter , thereby reducing the hernia and urinary obstruction . in the previous reports , 
 most symptomatic patients have been treated surgically , with conservative therapy reserved for asymptomatic patients . for the patient who is elderly or a poor surgical candidate 
 , retrograde stenting may provide safe reduction and efficacious treatment . 
 this endourological approach provides a minimally invasive means for the management of urinary obstruction caused by ureterosciatic herniation . 
Introduction
Case Presentation
Discussion