ureteropelvic junction ( upj ) obstruction has been classically treated through the standard open approach with outstanding results .
since anderson - hynes ( ah ) reported the first dismembered pyeloplasty , a great number of authors have published excellent results , with overall success rates of 90 - 100% .
their technique respected the basic principles of the open classical approach while providing less morbidity and faster recovery .
since then , transperitoneal and retroperitoneal approaches have been described and advocated by several authors , with excellent results . in order to ease laparoscopic repair and
decrease surgical time , many alternative time saving maneuvers and even robot assistance have been developed .
these alternative techniques helped in bringing the operative time close to that of open surgery and made laparoscopic pyeloplasty a more desirable alternative .
we evaluated the transmesocolic technique as a way to reduce operative time and facilitate repair by avoiding colon displacement and compare it with conventional retrocolic laparoscopic pyeloplasty ( rlp ) in cases of left sided ureteropelvic junction obstruction ( upjo ) .
between september 2006 and may 2012 , a total 130 laparoscopic pyeloplasties were performed . only left sided pelvi - ureteric junction obstruction were enrolled for study .
a total of 38 transmesocolic laparoscopic pyeloplasty ( tmp ) and 41 left sided rlp were performed .
the data were recorded in a prospective manner that included age , pelvic volume , presence of stone [ figure 1a and b ] , aberrant vessel , [ figure 1b ] operative time , analgesics requirement ( paracetamol 15 mg / kg body weight for children more than 10 kg of weight and 7.5 mg / kg body weight for children less than 10 kg of weight ) , time to accept oral feeds , drain removal . a dismembered ah pyeloplasty was performed in all patients .
double j stent ( djs ) was placed in 73.68% of patients in tmp group while 82.92% patients in rlp group .
based on pelvic volume , patients were divided into three groups : 
 group 1 : less than 50 ml ( 16 patients in rlp and 24 patients in tmp)group ii : 50 - 100 ml ( 14 patients in rlp and 10 patients in tmp)group iii : greater than 100 ml ( 11 patients in rlp and 4 patients in tmp ) . 
 
group 1 : less than 50 ml ( 16 patients in rlp and 24 patients in tmp ) group ii : 50 - 100 ml ( 14 patients in rlp and 10 patients in tmp ) group iii : greater than 100 ml ( 11 patients in rlp and 4 patients in tmp ) .
all patients with significant obstruction ( obstructed pattern and t1/2 more than 20 min ) as per the  well - tempered diuretic renogram  were taken for surgery .
all cases were done by a single surgeon who has experience of more than two hundred laparoscopic pyeloplasty including fifty cases of transmesocolic pyeloplasty . written consent of all patients was taken .
the patient was placed in the lateral decubitus position . using hasson 's canula by open technique , pneumoperitoneum up to 8 - 10 mm hg
two 3 mm or 5 mm ports were placed subcostally in the midclavicular line and mid - way between spinoumbilical lines respectively .
a mesocolic  window  was opened by dissecting the mesocolon with the harmonic scalpel .
this space was limited medially by the inferior mesenteric vein and laterally by the medial margin of the descending colon .
a 5 cm incision was then made longitudinally , lateral to the inferior mesenteric and gonadal veins , in between the medial and left colonic artery .
this area was free of vessels and the incision frequently enabled direct visualization of the lumbar ureter .
sometimes small branches of the left colonic artery were present and were clipped and sectioned , with no impairment of the colonic vascularization . in this way
, we created a peritoneal  window  that allowed a direct access to the renal pelvis .
whenever a wider operative field was necessary , the superior margin of the incision was suspended to the lateral abdominal wall with a suture .
needle aspiration of renal pelvis was done if pelvic capacity was more than 50 ml as to minimize the size of mesocolic window .
further , in larger pelvises , a stay suture passed percutaneously helps in better stabilization of the former .
the ureter and renal pelvis were carefully dissected to avoid unnecessary damage to their vasculature , whereas for the same reason , the kidney and ureter were not mobilized .
the upj was divided proximal to the renal pelvis and the obstructed part was left attached to the ureter . if necessary , the ureter was transposed over any aberrant vessels [ figure 1b ] .
the ureteral stent was placed by introducing the guide wire through a 16-gauge intravenous catheter sheath placed percutaneously under direct laparoscopic control .
then the ureter was spatulated , and a running suture on a small and half- circle [ sh ] needle was placed .
we used djs according to age ( length of jj = age of the child in years + 10 cm ) .
the anterior plane of the anastomosis was completed using the same suturing technique as for the posterior layer . in some cases
, we used a 2 mm percutaneous retractor on the anterior flap of the sectioned renal pelvis in order to stabilize the loose pelvis and facilitate the anastomosis .
the mesocolic window was usually closed with two or three hem - o - lok clips or by using a 3 - 0 polyglactin interrupted suture after placement of the suction tube .
the procedure began by incising at toldt 's line , dissecting the left colon from gerota 's fascia and reflecting it medially to visualize the renal hilum and upj .
median follow - up period for transmesocolic group was 12.5 months ( 9.5 - 62 months ) and 14 months ( 8 - 66 months ) for retro colic group .
follow - up included renal dynamic scan , first at 6 weeks after stent removal , then at 3 months and further 2 scans at 6 monthly intervals , resolution of symptom and or resolution of hydronephrosis on ultrasound .
between september 2006 and may 2012 , a total 130 laparoscopic pyeloplasties were performed . only left sided pelvi - ureteric junction obstruction were enrolled for study .
a total of 38 transmesocolic laparoscopic pyeloplasty ( tmp ) and 41 left sided rlp were performed .
the data were recorded in a prospective manner that included age , pelvic volume , presence of stone [ figure 1a and b ] , aberrant vessel , [ figure 1b ] operative time , analgesics requirement ( paracetamol 15 mg / kg body weight for children more than 10 kg of weight and 7.5 mg / kg body weight for children less than 10 kg of weight ) , time to accept oral feeds , drain removal . a dismembered ah pyeloplasty was performed in all patients .
double j stent ( djs ) was placed in 73.68% of patients in tmp group while 82.92% patients in rlp group .
based on pelvic volume , patients were divided into three groups : 
 group 1 : less than 50 ml ( 16 patients in rlp and 24 patients in tmp)group ii : 50 - 100 ml ( 14 patients in rlp and 10 patients in tmp)group iii : greater than 100 ml ( 11 patients in rlp and 4 patients in tmp ) . 
 
group 1 : less than 50 ml ( 16 patients in rlp and 24 patients in tmp ) group ii : 50 - 100 ml ( 14 patients in rlp and 10 patients in tmp ) group iii : greater than 100 ml ( 11 patients in rlp and 4 patients in tmp ) .
all patients with significant obstruction ( obstructed pattern and t1/2 more than 20 min ) as per the  well - tempered diuretic renogram  were taken for surgery .
all cases were done by a single surgeon who has experience of more than two hundred laparoscopic pyeloplasty including fifty cases of transmesocolic pyeloplasty . written consent of all patients was taken .
the patient was placed in the lateral decubitus position . using hasson 's canula by open technique , pneumoperitoneum up to 8 - 10 mm hg
two 3 mm or 5 mm ports were placed subcostally in the midclavicular line and mid - way between spinoumbilical lines respectively .
a mesocolic  window  was opened by dissecting the mesocolon with the harmonic scalpel .
this space was limited medially by the inferior mesenteric vein and laterally by the medial margin of the descending colon .
a 5 cm incision was then made longitudinally , lateral to the inferior mesenteric and gonadal veins , in between the medial and left colonic artery .
this area was free of vessels and the incision frequently enabled direct visualization of the lumbar ureter .
sometimes small branches of the left colonic artery were present and were clipped and sectioned , with no impairment of the colonic vascularization . in this way
, we created a peritoneal  window  that allowed a direct access to the renal pelvis .
whenever a wider operative field was necessary , the superior margin of the incision was suspended to the lateral abdominal wall with a suture .
needle aspiration of renal pelvis was done if pelvic capacity was more than 50 ml as to minimize the size of mesocolic window .
further , in larger pelvises , a stay suture passed percutaneously helps in better stabilization of the former .
the ureter and renal pelvis were carefully dissected to avoid unnecessary damage to their vasculature , whereas for the same reason , the kidney and ureter were not mobilized .
the upj was divided proximal to the renal pelvis and the obstructed part was left attached to the ureter . if necessary , the ureter was transposed over any aberrant vessels [ figure 1b ] .
the ureteral stent was placed by introducing the guide wire through a 16-gauge intravenous catheter sheath placed percutaneously under direct laparoscopic control .
then the ureter was spatulated , and a running suture on a small and half- circle [ sh ] needle was placed .
we used djs according to age ( length of jj = age of the child in years + 10 cm ) .
the anterior plane of the anastomosis was completed using the same suturing technique as for the posterior layer . in some cases
, we used a 2 mm percutaneous retractor on the anterior flap of the sectioned renal pelvis in order to stabilize the loose pelvis and facilitate the anastomosis .
the mesocolic window was usually closed with two or three hem - o - lok clips or by using a 3 - 0 polyglactin interrupted suture after placement of the suction tube .
the procedure began by incising at toldt 's line , dissecting the left colon from gerota 's fascia and reflecting it medially to visualize the renal hilum and upj .
median follow - up period for transmesocolic group was 12.5 months ( 9.5 - 62 months ) and 14 months ( 8 - 66 months ) for retro colic group .
follow - up included renal dynamic scan , first at 6 weeks after stent removal , then at 3 months and further 2 scans at 6 monthly intervals , resolution of symptom and or resolution of hydronephrosis on ultrasound .
between september 2006 and may 2012 , a total 130 laparoscopic pyeloplasties were performed . only left sided pelvi - ureteric junction obstruction were enrolled for study .
a total of 38 transmesocolic laparoscopic pyeloplasty ( tmp ) and 41 left sided rlp were performed .
the data were recorded in a prospective manner that included age , pelvic volume , presence of stone [ figure 1a and b ] , aberrant vessel , [ figure 1b ] operative time , analgesics requirement ( paracetamol 15 mg / kg body weight for children more than 10 kg of weight and 7.5 mg / kg body weight for children less than 10 kg of weight ) , time to accept oral feeds , drain removal . a dismembered ah pyeloplasty was performed in all patients .
double j stent ( djs ) was placed in 73.68% of patients in tmp group while 82.92% patients in rlp group .
based on pelvic volume , patients were divided into three groups : 
 group 1 : less than 50 ml ( 16 patients in rlp and 24 patients in tmp)group ii : 50 - 100 ml ( 14 patients in rlp and 10 patients in tmp)group iii : greater than 100 ml ( 11 patients in rlp and 4 patients in tmp ) . 
 
group 1 : less than 50 ml ( 16 patients in rlp and 24 patients in tmp ) group ii : 50 - 100 ml ( 14 patients in rlp and 10 patients in tmp ) group iii : greater than 100 ml ( 11 patients in rlp and 4 patients in tmp ) .
all patients with significant obstruction ( obstructed pattern and t1/2 more than 20 min ) as per the  well - tempered diuretic renogram  were taken for surgery .
all cases were done by a single surgeon who has experience of more than two hundred laparoscopic pyeloplasty including fifty cases of transmesocolic pyeloplasty . written consent of all patients was taken .
under general anesthesia , the patient was placed in the lateral decubitus position . using hasson 's canula by open technique , pneumoperitoneum up to 8 - 10 mm hg
two 3 mm or 5 mm ports were placed subcostally in the midclavicular line and mid - way between spinoumbilical lines respectively .
a mesocolic  window  was opened by dissecting the mesocolon with the harmonic scalpel .
this space was limited medially by the inferior mesenteric vein and laterally by the medial margin of the descending colon .
a 5 cm incision was then made longitudinally , lateral to the inferior mesenteric and gonadal veins , in between the medial and left colonic artery .
this area was free of vessels and the incision frequently enabled direct visualization of the lumbar ureter . sometimes small branches of the left colonic artery were present and were clipped and sectioned , with no impairment of the colonic vascularization . in this way , we created a peritoneal  window  that allowed a direct access to the renal pelvis .
whenever a wider operative field was necessary , the superior margin of the incision was suspended to the lateral abdominal wall with a suture .
needle aspiration of renal pelvis was done if pelvic capacity was more than 50 ml as to minimize the size of mesocolic window .
further , in larger pelvises , a stay suture passed percutaneously helps in better stabilization of the former .
the ureter and renal pelvis were carefully dissected to avoid unnecessary damage to their vasculature , whereas for the same reason , the kidney and ureter were not mobilized .
the upj was divided proximal to the renal pelvis and the obstructed part was left attached to the ureter . if necessary , the ureter was transposed over any aberrant vessels [ figure 1b ] .
the ureteral stent was placed by introducing the guide wire through a 16-gauge intravenous catheter sheath placed percutaneously under direct laparoscopic control .
then the ureter was spatulated , and a running suture on a small and half- circle [ sh ] needle was placed .
we used djs according to age ( length of jj = age of the child in years + 10 cm ) .
the anterior plane of the anastomosis was completed using the same suturing technique as for the posterior layer . in some cases
, we used a 2 mm percutaneous retractor on the anterior flap of the sectioned renal pelvis in order to stabilize the loose pelvis and facilitate the anastomosis .
the mesocolic window was usually closed with two or three hem - o - lok clips or by using a 3 - 0 polyglactin interrupted suture after placement of the suction tube .
the procedure began by incising at toldt 's line , dissecting the left colon from gerota 's fascia and reflecting it medially to visualize the renal hilum and upj .
median follow - up period for transmesocolic group was 12.5 months ( 9.5 - 62 months ) and 14 months ( 8 - 66 months ) for retro colic group .
follow - up included renal dynamic scan , first at 6 weeks after stent removal , then at 3 months and further 2 scans at 6 monthly intervals , resolution of symptom and or resolution of hydronephrosis on ultrasound .
in tmp group , 32 patients were boys and 6 were girls while 36 patients were boys and 5 were girls in rlp group .
djs was put in 73.68% patients in tmp group while 82.92% patients in rlp group . in rlp group ,
the mean operative time was 75.84 min ( time from port insertion to pyeloplasty ) and 135.4 min ( total operative time ) while it was 44.82 min and 104.82 min respectively in tmp group . on average
, tmp was 30 min shorter than classic rlp ( 104.8 min vs. 135.4 min ; p 0.05 ) .
there were no intra - operative complications or open conversions . in post - operative period
three patients had increased drain output , 1 patient had fever and hematuria , 1 patient had wound infection in rlp group while 1 patient in tmp group had increased drain output .
even patients with pelvic volume greater than 100 ml could be safely managed with prior aspiration [ figure 2a ] .
patients characteristic a case of left ureteropelvic junction obstruction with ( a ) secondary stones managed with transmesocolic approach , ( b ) crossing vessel ( arrow ) managed with transmesocolic approach ( a ) needle ( aspiration ) aspiration of dilated pelvis ( > 50 ml ) managed with transmesocolic approach .
( b ) antegrade jj stenting after completion of posterior wall anastomosis the mean hospital stay , mean drain removal time , mean time for oral intake and mean analgesic dose requirement was significantly lower in tmp group as compare to rlp .
all patients in rlp group had unobstructed drainage with static split renal function while in tmp group , 1 patient who had base line renal function of 10% , had further deterioration in function and needed nephrectomy .
in recent years , several minimally invasive procedures for pyeloplasty have emerged in order to decrease the morbidity associated with the classic open approach . at present ,
laparoscopic pyeloplasty has a success rate of 88 - 100% , which is similar to open surgery .
these authors described their technique , as a way of easing renal pedicle access and decrease operative time .
when a transperitoneal approach is chosen for a right - side lp , the access to the upj is simple as the surgeon has only to lift up the liver to identify the renal pelvis .
thus , the pyeloplasty can be performed through a small incision in the posterior peritoneum .
conversely , on the left side , mobilization of the descending colon is mandatory to identify the underlying renal fascia and to access the upj .
however , the descending colon can reduce the width of the operative field , especially in obese patients or when the colon is distended . in these cases , the introduction of a fourth trocar is often required to improve the exposure . to avoid the mobilization of the descending colon and all the inherent problems associated with bowel manipulation , a direct transperitoneal access to the left upj
castillo et al . , who reported series of 18 and 11 patients , respectively .
crossing vessels were present in 15.78% patients of tmp group while 18.42% patients in rlp group .
. stated , tmp is effective even in the presence of a large renal pelvis or abnormal polar vessels . in our study , on an average , tmp was 30 min shorter than classic rlp with a 22% reduction of operative time .
reported a reduction of 23% and romero et al . reported a reduction of 22.5% , which is similar to our study
the classic rlp approach needs mobilization of the descending colon and its mesentery , which is time consuming .
reported 3.6 days and 2.9 days in rlp and tmp group respectively . a study carried out by braga et al . in 2007 coded the mean hospital stay as 2.5 days .
the reduction of 19.2% was reported by romero et al . while in our study it was 29.7% .
the mean hospital stay in our study was 5.89 days ( range 3 - 17 days ) in rlp group while 4.14 days ( range 3 - 6 days ) in tmp group .
higher values are due the fact that poor sanitary condition at home and poor wound care would increase infection and morbidity , owing to which discharging of the patient is delayed .
mean analgesic dose requirement was significantly less in tmp group than rlp group ( p < 0.001 ) .
manipulation of the colon and adjacent abdominal wall can cause visceral pain . but generally tmp causes less pain when compared to rlp .
however , castillo et al . reported no difference in post - operative pain in either group .
mean time for oral intake and drain output was significantly less in tmp group than rlp ( p < 0.05 ) .
this data supports the facts that tmp is a feasible and reproducible technique that allows shorter operative times without increasing morbidity .
different comparative studies for tmp and rlp the limitations of this study were high mean age in both groups and no pain score was recorded during the study
. however , randomized prospective nature of the study and a substantial number of the cases compared in both arms contributed to the strength of this study .
moreover , inclusion of left sided of upjo avoided any sidewise bias for the operator .
transmesocolic approach for laparoscopic pyeloplasty enables a significant shorter operative time without increasing morbidity with comparable result to that of conventional retrocolic approach even in the presence of large renal pelvis , aberrant vessel and associated renal stones .
 objective : this prospective randomized study was designed to evaluate the feasibility and outcome of transmesocolic laparoscopic pyeloplasty ( tmp ) and compare it with retrocolic laparoscopic pyeloplasty ( rlp ) in pediatric and adolescent patients.materials and methods : between september 2006 to may 2012 , data of pediatric and adolescent patients undergoing laparoscopic pyeloplasty were recorded in a prospective manner . 
 data included age , pelvic volume , presence of stones , aberrant vessels , operative time , analgesics requirement and time to accept oral feeds and drain removal . 
 patients with left side pelviureteric junction obstruction with any size of pelvic volume , with or without renal stones and aberrant vessels were included in the study . 
 patients were assigned into two groups by simple randomization technique . 
 a total of 38 tmp and 41 left sided rlp were performed . 
 median follow - up period for transmesocolic group was 12.5 months ( 9.5 - 62 months ) and 14 months ( 8 - 66 months ) for retro colic group . 
 outcome for this study was adequate drainage on renal scan , improvement in symptom and or resolution of hydronephrosis on ultrasound . 
 statistical analysis was performed using the mann - whitney test.results:the mean patient age was 8.73 years in rlp and 7.73 years in tmp . in rlp group 
 the mean operative time was 75.84 min ( time from port insertion to pyeloplasty ) and 135.4 min ( total operative time ) while it was 44.82 min and 104.82 min respectively in tmp group . compared with classic rlp 
 , tmp cases showed a significant reduction in operative time.conclusions:the transmesocolic approach for left sided pyeloplasty enables a shorter operative time even in the presence of large pelvis , aberrant vessel and stones without increasing morbidity in comparison to rlp approach . 
INTRODUCTION
MATERIALS AND METHODS
None
Patients and data collection
Surgical technique
RESULTS
DISCUSSION
CONCLUSIONS