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the ureteropelvic junction obstruction ( ujpo ) is defined by a blockage of urine flow from the kidney to the proximal ureter .
this blockage can result in increased backpressure in the kidney , hydronephrosis , and progressive impairment of renal function .
upjo is the most common cause of prenatal hydronephrosis and occurs sporadically in 1 in 7501500 live births .
the frequency is higher in males compared to female 2:1 , the left side is affected in approximately two thirds of patients , and is bilateral in 1046% of cases . in 1949 ,
anderson and hynes described open dismembered pyeloplasty for treatment of upjo   since then it has been the main technique used for its high success rate . however , the classic lumbotomy access leads to an increased morbidity ; this developed an important number of minimally invasive procedures such as antegrade   or retrograde   endopyelotomy , balloon dilatation , or acucise endopyelotomy .
although these techniques are being used , their success rate is lower than open pyeloplasty .
the first laparoscopic pyeloplasty was described by schuessler et al .   in the early 90s . during the last decade
, laparoscopic pyeloplasty has been evolving in order to achieve the same results as open surgery , with lower rates of morbidity and complications .
we started to perform laparoscopic pyeloplasty at our center in 2004 and since then it has become the technique of choice for the treatment of upjo . in this study
a retrospective review of 62 laparoscopic pyeloplasties carried out at our center from march 2004 to june 2012 was done .
the data have been analyzed statistically at the biostatistics department in our center with the sas enterprise guide 3.0 program .
different data are described , such as symptomatology at diagnosis , patients age , function of the affected kidney using isotopic renogram values , presence of kidney stones , crossing vessels , operative time , length of stay , intraoperative and postoperative complications , and findings in follow  up .
success rate was measured in terms of clinical improvement reported by the patient , radiographic improvement in intravenous urography ( ivu ) demonstrated by appearance or upturn in the excretion of contrast , and the resolution of obstructive pattern in the diuretic renogram .
descriptive study results are shown in terms of absolute values , mean , standard deviation , and percentages . in the case of bilateral statistical tests ,
technical description ( figure 1 ) : in our center , after general anesthesia , the patient is placed at 45 degrees with the lateral opening centered on the operating table . after making pneumoperitoneum , we perform a transperitoneal approach with four ports . to obtain better cosmetic results , in the last two years
we have evolved the port placement technique to a 5 mm trocar for the 30 view telescopic lens , a transumbilical trocar , and three work trocars of 3 mm .
the colon is dissected along the avascular toldt line and rejected medially to expose the homolateral ureteropelvic junction ( upj ) .
the mobilization of the upj should be done with great care , identifying the possible existence of polar vessels .
once the opening and resection of upj is performed , in most cases we perform percutaneous ureteral catheterization with needle  nephroscopy trocar according to the technique described by alonso et al .  
the anastomosis is performed with 4/0vicryl suture . at the end of surgery approaching the peritoneum and gerota 's fascia is done and usually a drain is left in the surgical bed and is removed 2448 hrs later .
bladder catheter is left during the hospital stay ; it is removed 2448 hrs after surgery .
the ureteral catheter is removed in 46 weeks . left : vision of the upu through transperitoneal laparoscopic approach .
there have been a total of 62 laparoscopic transperitoneal pyeloplasties over a period of eight years .
the most frequent reason for consultation was ureteral pain with or without urinary tract infections ( 63% ) .
the mean patient age was 40 years , 52% of patients were female , and 94% of patients had a preoperative diuretic renogram demonstrating total or partial obstructive pattern , defined as a delay , or not spontaneous excretion and / or stimulated with diuretic . the right side was affected in 61% of cases and the left in the remaining 39% . 
 
notably , two patients had horseshoe kidneys and two patients had undergone previous minimally invasive procedures ( balloon or acucise endopyelotomy ) .
the presence of stones was only observed in 12 patients ( 19% ) and crossing vessels in 58% of cases .
the need for blood transfusion was observed only in two patients , one of them needed reoperation ; finding at surgery was a port site bleeding .
the mean follow  up of our patients is 45 months ( range 696 ) in which the success rate was recorded in 91% of cases , expressed in terms of clinical improvement , measured by patient satisfaction in the first review and later ones , improved excretion of contrast by the affected kidney in intravenous urography ( ivu ) ( figure 2 ) done at 6 months and resolution of obstructive pattern in the affected kidney renogram at 6 months ( figure 3 ) , defined as improvement in excretion with diuretic ( furosemide ) from an average of 20% in the preoperative renogram to 50% ( p = 0.0091 ) in the right kidney surgery and from 23% to 54% ( p = 0.0079 ) for the left kidney excretion respectively ; and an improvement in total excretion from 23% in the preoperative renogram to 54% ( p = 0.0061 ) in the right kidney surgery and 22% to 52% in the surgically treated left kidney ( p = 0.0022 ) .
right : ivu 6 months after surgery showing contrast excretion . the same patient in figure 2 .
laparoscopic reconstructive surgery is still in an early stage , although the first reports date back to the 90s . in 1993 , schuessler et al .   made and reported the first laparoscopic pyeloplasty . at first , the technical difficulties involved endoscopic suturing , affecting negatively in the results , with prolonged surgical times and a low success percentage , but today , laparoscopic pyeloplasty has been completely replaced endourology in treatment of upjo .
laparoscopic pyeloplasty has achieved similar results compared to the reference method represented by an open surgery , but offers the advantages of the minimally invasive surgery . as in other areas of surgery , there are no randomized controlled studies .
bestard vallejo et al .   in their study published in 2009 reported a similar rate of success between open pyeloplasty ( 100% ) and laparoscopic pyeloplasty ( 93% ) . 

table 2 summarizes the results of some of the largest published series on laparoscopic pyeloplasties including ours . as reflected in the table , there are no major differences between them in terms of mean age , operative time , success rate and complications .
the approach of choice depends on the previous surgical experience of the surgeon and his training . in our center
, we started with laparoscopic urologic surgery in 2002 and in our experience we prefer the transperitoneal approach for the upjo . 
 
results of several series of laparoscopic pyeloplasty in the literature , success rates are similar in the retroperitoneal and transperitoneal approach [ 19 , 20 ]
the predominant advantage in the retroperitoneal approach is the reduced risk of intraperitoneal injury . despite this , reduced working space can lead to problems in orientation , diminished vision , and difficulty surgical suturing , especially in obese patients .
the transperitoneal approach is more familiar to most surgeons and offers advantages such as : 1 ) a much wider workspace that would allow easier addition of techniques as transposition of polar vessels or remodeling of the pelvis and resolution secondary lithiasis , and 2 ) anatomical landmarks allowing better guidance and more easily reproduce the steps of open surgery .
the presence of stones is recognized as a complication of the upjo , and the diagnosis creates dilemmas regarding treatment .
inagaki et al .   have reported the presence in his series of kidney stones in 16% of patients , similar to our findings ( 19% ) . in our center
we have resolved most of the cases associated with kidney stones successfully with the use of laparoscopic instruments or even with the introduction of a flexible cystoscope through a trocar .
few series have an average long  term follow  up as ours ( 45 months ) , it is not clear in literature how long these patients should be followed in reviews .
proposed a visit at one to three months after surgery with ivu , furosemide renogram , and annually with ultrasound for at least three years .
we recommend the first visit a month after surgery and , after removal of the double j stent , performing basic analysis , ivu , and diuretic renogram .
followed by a visit every six months for the first two or three years with diuretic renogram to diagnose cases of treatment failure . the follow  up criteria are physician 
most of the re  stenosis cases are diagnosed in the first two years so it is important to emphasize the importance of following the review schedule to the patient and the need for the different complementary test .
site surgery ( less ) , but this leads to significant problems due to the proximity of instruments : flexible instruments intersect and collide , making the surgery more difficult to perform .
the performers of this technique emphasize the better cosmetic results and less pain that leads to a faster recovery of daily activities .
prospective and comparative trials are needed to see real differences between less and the conventional laparoscopic approach .
galisteo et al .   reflecting good success rate , concluding that the learning curve is lower , but the high costs is one of the obstacles for the development of this approach .
the development of high definition technology has improved the quality of the telescope lens of 5 mm , that is why we perform in our hospital since 2010 laparoscopic pyeloplasty with this equipment ; also the evolution in 3 mm laparoscopic instruments leads us to use this technology in our center in order reduce the degree of invasion and provide better cosmetic results to our patients .
following the evolution of laparoscopic reconstructive surgery , transperitoneal laparoscopic pyeloplasty has become the gold standard for the treatment of upjo in our department , in primary cases and in those where other techniques have been attempted , this is based in the high success rate , short hospital stay , and low intra and postoperative complications .
up should be frequent in the first two years , after that it 's surgeon  dependent .
the improvement in 3 mm and 5 mm equipment make this technique less invasive in order to obtain better cosmetic results .
upjo  ureteropelvic junction obstruction ivu  intravenous urography upj  ureteropelvic junction less  laparo  endoscopic single  site surgery
introductionlaparoscopic pyeloplasty was first described by schuessler . during the last decade , this technique has been developed in order to achieve the same results as open surgery , with lower rates of morbidity and complications . in this study 
 we review our experience using laparoscopic pyeloplasty as the gold standard for the treatment of the ureteropelvic junction obstruction ( upjo).material and methodswe performed a retrospective review of 62 laparoscopic pyeloplasties carried out at our center . in the last 2 years we used 3 mm and 5 mm ports in order to achieve better cosmetics results . 
 demographic data is described and the functionality of the affected kidney and surgical data , among others were analyzed statistically . in the case of bilateral statistical tests 
 were considered significant as those with p values < 0.05.resultsthe most frequent reason for consultation was ureteral pain . 
 patients mean age was 40 years and 94% of them had preoperative renogram showing a full or partial obstructive pattern . 
 the right side was affected in 61% of cases and the left in the remaining 39% . 
 the presence of stones was observed in 12 patients and crossing vessels in 58% of cases . 
 the average stay was 3.72 days . 
 post  surgery complications were observed in two patients . 
 the operative time was 178 minutes . 
 mean follow  up was 45 months and a success was achieved in 91%.conclusionsthe transperitoneal laparoscopic pyeloplasty has become the gold standard for the treatment of ureteropelvic junction stenosis in our center because of high success rate , shorter postoperative stay , and low intra and postoperative complications .