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 .