although renal pelvic stones larger than 20 mm in size are treated by percutaneous nephrolithotomy ( pcnl ) , they can be directly removed by pyelolithotomy .
direct removal by pyelolithotomy is especially indicated in cases of failed extracorporeal shock wave lithotripsy ( swl ) or endoscopic removal and in patients with anatomical variations in the location or shape of the kidney ; concomitant abnormalities , including ureteropelvic junction obstruction ; and urinary infections needing definitive clearance of calculi .
although open pyelolithotomy is possible , laparoscopic surgery is preferred because it is less invasive .
since the first laparoscopic nephrectomy , laparoscopic surgery has been proven to have several advantages over open surgery .
nowadays , laparoscopic surgery is increasingly being used as a standard operation in many urologic procedures .
the primary objectives of attempts to further develop laparoscopic techniques and instruments are reductions in operative morbidity and improved cosmesis , which has led to the development of laparoendoscopic single - site ( less ) surgery .
this procedure has gained popularity over other techniques because it requires a smaller incision , which helps to improve postoperative recovery and cosmesis .
herein , we present our initial experiences with four patients who underwent transumbilical less pyelolithotomy for the treatment of large stones in the renal pelvis . for the procedures , we used a carter - thomason ( ct ) needle grasper instead of an additional port .
between october 2010 and november 2011 , less pyelolithotomy was performed in four patients ( one woman and three men ) .
the mean age of the patients was 57.8 years ( range , 39 to 71 years ) , and their mean body mass index was 23.01 ( range , 18.42 to 26.99 ) .
a homemade single - port device , made by using a size-6 surgical glove and a small - sized alexis wound retractor ( applied medical resources co. , rancho santa margarita , ca , usa ) , was inserted into the peritoneal cavity through a 2.5-cm periumbilical incision .
one 5-mm and two 11-mm trocars were inserted into the glove of the homemade port and were fixed by using rubber bands .
carbon dioxide insufflation was used to maintain an intraperitoneal pressure of 14 mmhg , and a 10-mm 30 laparoscope ( endoeye , olympus co. , tokyo , japan ) was inserted into the peritoneal cavity .
the operation was performed by using standard 5-mm and 10-mm laparoscopic instruments , ultrasonic scissors ( sonosurg , olympus co. ) , and 5-mm articulating instruments ( cambridge endo , framingham , ma , usa ) .
the ureter was identified in the retroperitoneal fat medial to the psoas muscle and was traced to the renal pelvis .
the stone was palpated in the renal pelvis , which was dissected to release the adhesions . a needle grasper from the ct needle suture device ( inlet medical , eden prairie , mn
, usa ) was inserted in the peritoneal space at the subcostal margin ; the tip of the device was covered with a plastic cap ( fig .
2 ) . the device was used to manipulate the liver , spleen , and kidney .
the pelvis was incised longitudinally ; the incision was started by using a hooked blade and was continued by using laparoscopic scissors .
the stone was removed with laparoscopic forceps . if a large stone adhered to the pelvic wall or extended to the calyx , it was gently rotated by using 10-mm laparoscopic forceps to facilitate its extraction . running 4 - 0 vicryl sutures
the ct needle grasper , without a cap , was useful for grasping the suturing material .
after completion of the suturing , the stone was removed , and a jackson - pratt drain was placed and fixed through the periumbilical incision ( fig .
the patient was positioned in a 70 lateral position . a homemade single - port device , made by using a size-6 surgical glove and a small - sized alexis wound retractor ( applied medical resources co. , rancho santa margarita , ca , usa ) , was inserted into the peritoneal cavity through a 2.5-cm periumbilical incision .
one 5-mm and two 11-mm trocars were inserted into the glove of the homemade port and were fixed by using rubber bands .
carbon dioxide insufflation was used to maintain an intraperitoneal pressure of 14 mmhg , and a 10-mm 30 laparoscope ( endoeye , olympus co. , tokyo , japan ) was inserted into the peritoneal cavity .
the operation was performed by using standard 5-mm and 10-mm laparoscopic instruments , ultrasonic scissors ( sonosurg , olympus co. ) , and 5-mm articulating instruments ( cambridge endo , framingham , ma , usa ) . the less procedure replicated the procedure used in open ureterolithotomy ( supplementary data ) .
the ureter was identified in the retroperitoneal fat medial to the psoas muscle and was traced to the renal pelvis .
the stone was palpated in the renal pelvis , which was dissected to release the adhesions . a needle grasper from the ct needle suture device ( inlet medical , eden prairie , mn
, usa ) was inserted in the peritoneal space at the subcostal margin ; the tip of the device was covered with a plastic cap ( fig .
2 ) . the device was used to manipulate the liver , spleen , and kidney .
the pelvis was incised longitudinally ; the incision was started by using a hooked blade and was continued by using laparoscopic scissors .
if a large stone adhered to the pelvic wall or extended to the calyx , it was gently rotated by using 10-mm laparoscopic forceps to facilitate its extraction . running 4 - 0 vicryl sutures
the ct needle grasper , without a cap , was useful for grasping the suturing material .
after completion of the suturing , the stone was removed , and a jackson - pratt drain was placed and fixed through the periumbilical incision ( fig .
all less ureterolithotomies were completed successfully without conversion to conventional laparoscopic or open surgery ; no additional ports were needed .
the mean operative time was 124.5 minutes ( range , 80 to 157 minutes ) .
the mean estimated blood loss was 255.2 ml ( range , 120.0 to 549.9 ml ) .
there were no significant complications , except in one patient who required transfusion because he underwent simultaneous transurethral resection of the prostate .
postoperative pain control was achieved by using patient - controlled analgesia with 40 mg of morphine and 150 mg of ketorolac for 2 days .
the mean duration of hospital stay was 8.3 days ( range , 5 to 11 days ) .
the stones were located in the renal pelvis ; one patient had a large stone occupying the renal pelvis and lower pole .
the mean diameter of the stones was 3.9 cm ( range , 3.0 to 5.1 cm ) . chemical analysis of the stones showed that three patients had calcium - containing stones and one patient had a uric acid stone ( table 1 ) . postoperative radiologic study showed no remnant stones in the renal pelvis .
it affords a high chance of complete stone removal even with large stones and corrects a concomitant ureteropelvic junction obstruction .
continuous advancements in laparoscopic surgery may lead to laparoscopic pyelolithotomy ( lpl ) becoming a feasible modality for the treatment of renal pelvic stones .
in particular , lpl can provide a magnified image to identify aberrant vessels and vascular injury .
although it is technically difficult to complete sutures in the case of a huge renal pelvis , lpl allows easy detection of the obstruction site .
although their success rate was low ( 62.5% ) because of their inexperience and the unavailability of instruments , they recommended the use of laparoscopic suturing techniques and placement of double - j stents .
jordan et al .   also had performed an lpl procedure by using a transperitoneal approach in a 16-month - old child .
successful cases after these initial reports suggest that lpl can be used as an alternative to pcnl .
performed lpl with a transperitoneal approach in five patients who had renal anomalies such as horseshoe and pelvic kidneys .
however , goel and hemal   reported that lpl had a longer operative time and convalescence period , was more invasive , and had less cosmetic advantage .
they concluded that lpl should be performed in patients who require adjunctive procedures or have urinary anomalies . in their study of lpl with the retroperitoneal approach and swl , chander et al
.   showed that lpl resulted in better stone clearance , fewer hospital visits , and a lower analgesic requirement .
they concluded that the main cause of the lack of popularity of lpl was its steep learning curve .
laparoscopic surgery involving a single incision and multi - lumen ports is one such procedure .
less surgery yields superior cosmetic results and shows faster recovery than the standard laparoscopic surgery in a large - volume center .
choi et al .   reported less ureterolithotomies with the use of a homemade single - port device , a double - j ureteral stent , and intracorporeal sutures .
wen et al .   reported 10 cases of less ureterolithotomies through the retroperitoneal approach and compared these with conventional laparoscopic ureterolithotomy .
they found no difference in operative time , estimated blood loss , or postoperative analgesic duration .
cosmetic results were superior in the less group according to both the study nurses ' and the patients ' assessments .
however , we could not find any reports describing less pyelolithotomies in a large series with technical details of the procedure .
it is difficult to dissect around the renal pelvis because of adhesions from inflammation and the risk of damaging the major blood vessels .
finally , pcnl is an existing effective method for treating large renal pelvic stones . despite these limitations ,
we have performed less pyelolithotomy and found that it increases the stone clearance rate , is minimally invasive , and offers cosmetic advantages .
we found that less pyelolithotomy showed acceptable operative results , including complete stone clearance , that were comparable to those of conventional laparoscopy .
however , one patient required blood transfusion because of technical difficulty in dissecting the renal pelvis , which showed abundant perirenal fat and adhesion ; moreover , this patient underwent a simultaneous transurethral resection of the prostate .
the mean duration of hospital stay was longer than that previously reported for lpl because the medical insurance system of our country differs from the insurance systems in other countries .
we used a homemade single - port device with three channels of an 11-mm trocar for the right hand of the operator , an 11-mm trocar for the camera holder , and a 5-mm trocar for the left hand of the operator .
although it took time to make the device and insert it into the peritoneal cavity , and there was a possibility of tearing during insertion of the instrument , the device itself was developed at a low cost and provided high flexibility .
the broad range of instrumental movement possible because of the flexibility of the device enabled us to perform the laparoscopic intracorporeal suture by using a rigid needle holder .
the ct needle suture device consisted of a 5-mm , 10-mm , or 12-mm cone ; a sharp needle ; and a single - action grasper .
.   showed that the ct needle suture device facilitated the fastest trocar wound closure with 100% intraoperative success .
a cap of a 20-gauze needle and a short segment of fluid line attached to the grasper were useful for manipulating the organs to clear the operative field .
it was often used as a retracting instrument for liver , spleen , kidney , and bowel . for facilitating the suture , the grasper without the cap
after removal of the device , the insertion site did not require fascial or skin closures .
our study had several limitations . while performing this small pilot study of our technique , we did not obtain enough cases and data to compare less pyelolithotomy with swl or pcnl .
further surgical experiences and longer follow - ups are needed to evaluate the benefits of this technique with respect to cosmesis and convalescence and to compare the findings with those obtained for open or laparoscopic pyelolithotomies .
although our study had certain limitations , our findings indicated that less pyelolithotomy with the use of a homemade port and a ct needle grasper can be a feasible treatment modality for large renal pelvic stones .
compared with open or laparoscopic pyelolithotomies , less pyelolithotomy is less invasive and has greater cosmetic advantages .
the ct needle grasper was useful for resolving the technical difficulties involved in the less surgery without an additional trocar .
an accompanying video can be found in the ' urology in motion ' section of the journal homepage ( www.kjurology.org ) .
the supplementary data can also be accessed by scanning a qr code located on the title page of this article .
 purposeto study the feasibility and safety of the procedure , we present our early experience with laparoendoscopic single - site ( less ) pyelolithotomy performed by use of a carter - thomason needle grasper.materials and methodsfour patients underwent less pyelolithotomy for the removal of renal pelvic stones . 
 the patients ' mean age was 57.8 years , and their mean body mass index was 23.01 . 
 we used a homemade single - port device made with a surgical glove that was inserted into a 2.5-cm periumbilical incision . 
 the operation was performed transperitoneally by using a carter - thomason grasper . 
 after removal of the stone , a double - j stent was placed in situ , and laparoscopic intracorporeal suturing was performed . 
 no additional ports were used.resultsall surgeries were completed successfully without conversion to conventional laparoscopy or open surgery . 
 the mean operative time was 124.5 minutes , and the mean estimated blood loss was 255.2 ml . there were no significant complications , except in one patient who required a blood transfusion . 
 the mean duration of hospital stay was 8.3 days . 
 the mean stone size was 3.9 cm . 
 chemical analysis of the stones showed that three patients had calcium - containing stones and one patient had a uric acid stone . 
 postoperative radiologic study showed a stone clearance rate of 100%.conclusionsour results , albeit limited , showed that less pyelolithotomy is a feasible and safe procedure . especially with the use of a carter - thomason needle grasper 
 , this operation can be performed without an additional port . 
INTRODUCTION
MATERIALS AND METHODS
1. Technique
RESULTS
DISCUSSION
CONCLUSIONS
SUPPLEMENTARY DATA