prostate cancer is the most common type of cancer affecting japanese men , and radical prostatectomy is an established treatment option for both localized and locally advanced prostate cancers .
the development of minimally invasive surgical techniques has resulted in a greater focus on achieving optimal functional outcomes in patients undergoing this procedure .
laparoscopic radical prostatectomy ( lrp ) is an example of a minimally invasive technique for treating prostate cancer [ 2 , 3 ] which is currently performed in japan . compared to the open approach ,
surgeons with experience in lrp consider it advantageous because of the improvements associated with better optical magnification , less blood loss , less postoperative pain , and rapid resumption of normal activities [ 5 , 6 ] . despite the benefits of lrp
, its use is declining worldwide . in the united states , it represents less than 5% of the total procedures used for treating prostate cancer , whereas robot - assisted laparoscopic radical prostatectomy ( ralp ) is now the most widely used procedure . in japan ,
ralp has not been widely employed because of the lack of insurance coverage available for this technique , prior to april 2012 . since the introduction of ralp in frankfurt in 2000
robotic systems provide many advantages , including three - dimensional ( 3d ) vision , enhanced magnification , tremor filtering , and motion scaling .
in addition , the endowrist technology aids in intracorporeal suturing and ergonomic comfort . as any new surgical technique , ralp is associated with a learning curve in terms of operative outcomes ( operating time , blood loss , hospital stay , and complications ) , oncological outcomes ( positive margin rate and recurrence ) , and functional outcomes ( incontinence and erectile dysfunction rates ) [ 9 , 10 ] .
we aimed to evaluate the outcomes of the first 300 patients treated using ralp at our facility .
we chose to focus on the total operative time , duration of robotic surgery , blood loss , intraoperative and immediate postoperative complications , duration of postoperative urethral catheterization , tnm staging , surgical margin status , urinary continence after surgery , and prostate - specific antigen ( psa ) elevation recurrence .
between may 2011 and november 2013 , 300 consecutive patients were recruited for this study , each of whom underwent ralp at nagoya city university hospital .
the study received approval from our institutional review board (  robot - assisted laparoscopic radical prostatectomy for prostate cancer ,  number 46 - 10 - 0009 ) and conforms to the provisions of the declaration of helsinki .
for all patients , the preoperative assessment included detailed patient histories , clinical examinations , serum psa measurements , biopsy findings , gleason score measurements , bone scan results , and contrast - enhanced computed tomography ( ct ) or magnetic resonance imaging ( mri ) findings .
baseline demographic clinical staging was based on tnm staging ( union internationale contre le cancer 2002 classification ) , and only patients with t13n0m0 stage cancers were considered for ralp .
all patients eligible for radical prostatectomy were offered ralp , using a 4-arm da vinci - s robotic system ( intuitive surgical , sunnyvale , ca , usa ) .
our technique was based on that used at the vattikuti institute ( detroit , mi , usa ) , combined with the use of diathermy scissors .
previously , we had performed lrp using a posterior approach to the seminal vesicle , according to the montsouris method .
briefly , the rectum was retracted in a cephalad dissection by the assistant . the superior peritoneal arch ( created by the impression of the foley balloon )
was grasped by the assistant or the third arm of the da vinci - s and lifted upwards .
a curvilinear incision was then created , using the monopolar scissors , midway between the anterior rectal wall and the grasped arch .
deeping of the incision by blunt dissection through the fibroalveolar tissue revealed both vas deferens ( vds ) .
the vds were dissected free , approximately 3  cm from the prostate , and transected .
blunt dissection of the anterior fibrovascular tissue overlying the seminal vesicles ( svs ) continued laterally . once the dissection was completed to the level of the base , blunt medial dissection freed the posterior surface of the svs .
after both svs were completely dissected , upward traction on both svs and vds facilitated an incision into the denonvillier 's fascia , which allowed the posterior dissection to continue to the level of the rectourethralis fibers .
dorsal vein control was achieved using 2 - 0 v - loc on a 37 mm needle ( covidien , mansfield , ma , usa ) that was placed distally around the complex 3 times before division .
clipping of the vascular pedicles with hem - o - lock ( teleflex , limerick , pa , usa ) 5 and 10 mm clips was used to control the posterolateral small vessels when performing ( typically interfacial ) nerve sparing .
the use of the rocco suture , using 3 - 0 v - loc on a 26  mm needle ( covidien ) , was also adopted .
vesicourethral anastomosis was performed using two 3 - 0 v - loc sutures on 17  mm needles ( covidien ) , tied together , forming a continuous suture running posteriorly and to either side .
this also included an additional anterior racket stitch in cases with large bladder necks , according to the vattikuti technique .
after the first 70 cases , anastomosis was performed using two 3 - 0 pdsii ( ethicon endo - surgery , cincinnati , oh , usa ) sutures , retightened with lapra - ty ( ethicon endo - surgery ) at the 3 and 9 o'clock positions .
after the anastomosis was completed , a leak test was performed using 150  ml of saline , allowing an additional suture to be placed in the rare event of a leak .
cystography was performed between 5 and 8 days after the procedure , prior to catheter removal , unless the anastomosis failed the leak test .
the entire surgical team underwent 2 days of intensive training at sukagawa training center in fukushima or fujita health university training center in aichi , japan , and received surgical practice at the st .
augustine hospital in bordeaux , france , and/or the yonsei university severance hospital in seoul , korea .
side - specific intrafascial dissection of the neurovascular bundle was performed on prostates with palpable nodules , those with biopsy gleason scores of 3 + 3 or 3 + 4 , those with a maximum percentage of positive biopsy of < 10% ( depending on the location of the biopsy ) , and those with medially located positive cores or in the absence of suspected extracapsular extensions on mri .
however , prostates with a single positive biopsy and a gleason score of 4 + 3 or those with a maximum percentage of positive biopsy of > 10% comprising a medial core without signs of extracapsular extensions were also considered suitable for side - specific intrafascial dissection .
these criteria were not considered strict rules but rather general guidelines . based on these specific indications ,
the number of patients who underwent nerve - sparing lrp ( unilateral ) was only 65 .
after the first 90 patients , we had been accustomed to robotic procedure , which showed stability after the ralp technique ; all further intermediate and high d'amico risk   patients underwent lymph node dissection .
histopathological assessment included the final gleason score , degree of positive margin , and sv or lymph node involvement .
pathological processing of the specimens included 4 mm sectioning of the whole gland ; a positive margin was defined as the presence of malignant glands in direct contact with the inked surface .
patients were then followed up at regular intervals with serial psa monitoring and assessment of functional outcomes , including continence and erectile function .
for the 199 patients who were followed up for more than 6 months , we confirmed the continence rate by using a questionnaire at 1 , 3 , and 6 months after ralp .
for this study , the following data were collected and reviewed : patient age , body mass index ( bmi ) , total operating time ( including port placement , docking of the robot , dissection , anastomosis , and lymphadenectomy ) , duration of robotic surgery , estimated blood loss , hospital stay , presence or absence of urinary incontinence ( pad usage ) , duration of postoperative bladder catheterization , intraoperative complications , immediate postoperative complications ( appearing within the first month after surgery ) , long - term complications ( appearing after the first postoperative month ) , tnm staging , and surgical margin status .
biochemical recurrence of prostate cancer , defined as increases in serum psa levels of more than 0.1  ng / ml at 2 consecutive follow - up assessments , was also recorded . to examine the procedural learning curve ,
statistical significance was assessed using the student 's t - test and the mann - whitney u test .
mean patient age was 67.2  5.5 years ( range : 4178 years ) , and mean bmi was 23.3  2.6  kg / m ( range : 15.230.8  kg / m ) .
the mean psa level at diagnosis of prostate cancer was 9.16  6.50  ng / ml ( range : 2.2055.31  ng / ml ) . at biopsy , 96 , 123 , and 81 patients had a gleason score of 6 , 7 , and 810 , respectively .
further , 3 , 73 , 85 , 32 , 91 , 12 , and 4 patients had a preoperative clinical stage of t1a - b , t1c , t2a , t2b , t2c , t3a , and t3b , respectively . in 1 patient , open surgery was ultimately performed because of severe adhesions in the abdominal cavity after gastrectomy .
one hundred forty - two of the 300 patients were initially diagnosed with localized prostate cancer elsewhere before being referred to our institution to undergo ralp ; 16 of these patients had received neoadjuvant hormonal therapy at the first hospital .
eighty - seven patients underwent abdominal operations before ralp , the most frequent being appendectomy in 64 patients ( 21.3% ) , followed by cholecystectomy in 8 patients ( 2.7% ) and gastrectomy in 4 patients ( 1.3% ) .
the median follow - up duration was 15 months ( range : 131 months ) .
the mean mass of removed prostate tissue was 44.4  15.9  g ( range : 14132  g ) . the median total operating time was 220  min ( mean : 222  43  min , range : 120410  min ) , with a median duration of robotic surgery of 160  min ( mean : 165  40  min , range : 75345  min ) ( table 2 ) .
some patients required longer operative times because they had larger prostates , prostates that projected into the bladder , or adhesions to the surrounding tissue .
the duration of robotic surgery remained stable despite increasing experience , after the initial 2 cases .
there was no significant difference in the median duration of robotic surgery ( 155  min , 156  min , 178  min , 169  min , 172  min , and 162  min for cases 150 , 51100 , 101150 , 151200 , 201250 , and 251300 , resp . ) .
each surgeon required some additional time during the initial cases . the median estimated blood loss , including that in the urine , was 200  ml ( mean : 277  324  ml ; range : 43250  ml ) .
eight patients showed blood loss of > 1000  ml , but the hemoglobin levels , immediately after surgery , in 4 of these patients were > 9  g / dl .
however , 2 patients who experienced blood loss of 12503250  ml and 2 patients who developed postoperative hematomas required allogeneic blood transfusion .
the volume of estimated blood loss tended to decrease with increasing surgeon experience , although there was major bleeding in some cases that did not otherwise exhibit any significant differences .
there was no significant difference in the median blood loss ; however , a tendency for slightly higher blood loss was observed in the initial 50 cases compared to the other groups ( 271  ml , 201  ml , 250  ml , 154  ml , 166  ml , and 150  ml for cases 150 , 51100 , 101150 , 151200 , 201250 , and 251300 , resp . ) .
the median duration of catheterization was 7 days ( mean : 7.7  4.2 days ; range : 546 days ) , and patients undergoing ralp had a median postoperative hospitalization period of 11 days ( mean : 10.4  4.9 ; range : 750 days ) ; the duration of hospitalization did not change with increasing surgical experience .
one patient developed postoperative hematoma , infection , and ileus and required prolonged catheterization and hospitalization .
the number of patients in each pathological stage is given in table 3 . in 89 patients ( 29.7% ) ,
a change in the positive margin rate was seen over time for pt2 and pt3 cases ( figure 1 ) .
the rate of positive margins in pt2 cases was observed to decline with increasing surgeon experience ; there were positive surgical margins in 31.7% of the first 50 cases and this declined to 21.4% for cases 251300 .
there were no significant changes in the positive surgical margin rates in pt3 cases , but there were comparatively few such cases .
the changes observed in the rates of positive margins , in both pt2 and pt3 cases , for different locations are shown as a function of the number of cases ( figure 2 ) .
apical and posterolateral margins were generally seen most frequently . however , in cases 51100 , positive bladder neck margins were also frequently observed .
psa recurrence was seen in 5 cases of pt3 cases and 2 cases of pt2 cases .
intraoperative and immediate postoperative complications occurred in 9 out of the 300 cases ; the details are listed in table 4 .
urinary continence was also assessed in 199 patients who were followed up for more than 6 months . to avoid subjectivity in assessment and to facilitate comparability ,
of the 199 patients treated using ralp , 57.8% used a maximum of 1 pad per 24  h at 3 months postoperatively , and this percentage increased to 82.4% at 6 months .
sufficient erectile function for sexual intercourse , with or without augmentation using phosphodiesterase 5 inhibitors , was noted in 76.9% of the patients who underwent unilateral nerve sparing .
the benefits of robot - assisted surgery are most apparent for areas of the body that are anatomically confined and difficult to access with open surgery , such as the deep areas of the pelvis . because of this
advantages include better ergonomics ; scaled , filtered , and miniaturized movements facilitating more precise dissection and suturing ; magnified , stable 3d vision ; and a shorter learning curve than that for basic laparoscopy .
several studies have documented the positive short - term and long - term outcomes using this technology [ 1618 ] .
however , given the cost of the robotics , these systems are still relatively new in japan and in developing nations with limited resources .
we acquired the 4-armed da vinci - s surgical system in 2011 and have been offering robot - assisted surgery to most patients with clinically localized prostate cancer since then .
the operative data for ralps was compared to data for our first 160 lrp cases , which were performed between august 2000 and december 2006 ( table 2 ) .
preoperative characteristics of patients who underwent lrp have no difference from those of ralp patients , except for biopsy gleason score ( table 1 ) .
the operative times and blood loss with ralp were significantly lower than those observed with lrp .
in addition , the need for blood transfusions and the frequency of severe complications ( e.g. , rectal injury ) with ralp were also less than those observed with lrp .
the duration of urethral catheter placement was similar between the 2 procedures ; however , the length of hospitalization following ralp was less than that following lrp .
there is no significance between postoperative pathological diagnosis of ralp and that of lrp ( pt2 : 83.0% , pt3 : 16.3% in ralp , pt2 : 78.1% , and pt3 : 21.9% in lrp , resp . ) .
the mean patient age in the present study was older ( 67.2  5.5 years ) than that observed in prior studies conducted in western countries .
reported a mean age of 57.4 years , and that reported by tewari et al .  
however , a similar average age of 63.2 years was reported by patel et al . .
the older average age noted in the present study may be because of a lower overall incidence of prostate cancer among japanese men resulting from racial and environmental differences .
currently , in japan , psa screening often triggers a diagnosis of prostate cancer , yet the mean serum psa level of 9.18  ng / ml in this study was nearly 1.5 times that reported in many other western studies ; for example , the mean serum psa value was 6.9  ng / ml in the series reported by patel et al . .
the high psa levels noted in this study may be attributable to the preponderance of stage t2 cancers , accounting for a steeper learning curve for t2 cancers than for t1c cancers . in the current study
, mris were performed using a 3-tesla system to detect prostate cancer . with this system ,
the performance of diffusion - weighted imaging is better than t2-weighted imaging for prostate cancer diagnoses .
we believe that the higher accuracy of the mri system resulted in the accurate identification of the increased percentage of clinical t2 cases in our study .
this was despite the fact that prostate size ( 44.4  15.9  g ) was similar to that reported in studies by kaul et al .  
( 48.6  12.1  g ) and tewari et al .   ( 45.3  12.3  g ) . a consistent long - term oncological follow - up study should be conducted to better address this issue .
the median duration of the robot - assisted surgery was 160  min in this study . in a prior multi - institutional report , schatloff et al .   reported a median operative time for ralp of 165  min among surgeons with a median experience of 460 cases .
our data show that a similar mean operative time was reached after the first 10 cases for each surgeon . a reason for this may be that surgeons involved in the present study had considerable prior experience in lrp ( over 50 cases each ) .
others have reported shorter mean duration of robotic surgery of 122  min   and 130  min .
patel et al .   also noted that the duration of robotic surgery decreased with increasing surgeon experience ; it was 202  min for the first 50 cases and less than 100  min for the last 100 cases . in the present series ,
the reason for the apparent rapidity with which our surgeons reached this plateau in the length of the operation may be related to their prior lrp experience , the comparative ease with which ralp can be mastered as compared with lrp and the fact that only 8 surgeons perform the ralp operation .
the estimated median blood loss was also relatively high in the present study ( 276.5  323.8  ml ) , with 4 patients ( 1.3% ) requiring blood transfusions .
the mean blood loss reported by tewari et al .   was 160  ml and that reported by kaul et al .  
a review of the outcomes reported by high - volume centers , including studies involving at least 250 cases , showed that the mean estimated blood loss for ralp was 164  ml . in their first 100 cases ,
mikhail et al .   reported a mean blood loss of 340  238  ml .
the reduced levels of blood loss are ones of the chief advantages of ralp over open surgery . only 1 case ( 0.3% ) , in which the patient had severe adhesions in the abdominal cavity , was converted to open surgery in the current patient series .
patel et al .   reported a conversion rate of 0.6% in their series of 500 patients , whereas mikhail et al .  
, 2 cases with posterior bladder perforations were immediately sutured by laparoscopy and no rectal injury was encountered . during ralp
, many surgeons currently employ the modified montsouris technique , as initially described by menon et al .
first , the surgeon is offered a larger working area to dissect the vd and sv .
the surgeon is , therefore , able to visualize the vd as it courses towards the internal inguinal ring and prior to its transection .
the second benefit of an initial posterior dissection is the visualization offered by the absence of pooled blood . for surgeons who dissect the sv only after bladder neck transection
, blood collects in the fossa created in the rectoprostatic space and hampers tissue visualization .
third , the most important benefit of the technique is the safe and reliable posterior bladder neck transection . by ensuring complete mobilization of the prostate
, the surgeon can through the anterior layer of denonvillier 's fascia into the previously dissected space .
in a recent study by mcnicholas , increased ralp experience resulted in a reduced occurrence of complications . in our series , both the overall complications and the major complications decreased significantly with increasing experience , reaching levels similar to those published in studies involving very experienced surgeons .
the perioperative complication rate in the current study was comparable to that of most contemporary series [ 2428 ] , despite the fact that the surgeons involved in the present work had limited ralp experience .
each of the surgeons involved in this study had performed over 50 lrps , and all underwent ralp training using videos , lectures , or hands - on experience .
atug et al .   examined the positive surgical margins of the first 100 ralp procedures at their hospital , according to case numbers , and observed rates of 45% , 22% , and 11.7% , for the first , second , and third groups of patients , respectively .
in another recent study , menon et al . reported an overall positive margin rate of 25.1% in a series of 1384 patients .
in t2 and t3 patients , the positive margin rate gradually decreased with additional experience ( figure 2 ) .
the positive margin rate in our study was relatively high , especially for cases 51100 and for tumors located at the bladder neck . in these cases ,
the prostate dissection was approached from the bladder neck , avoiding the large , inner bladder neck . during the cutting of the bladder and prostate , which may have moved to the side , the absence of tactile sense with the robotic system may have contributed to the high rate of positive margins .
when the dissection approach was changed slightly , to the bladder side for cases 101300 , the rate of positive margins decreased .
improvements in functional outcomes , such as continence and potency rates , because of the surgical experience have been reported in a number of prior studies . despite varying outcome definitions in these studies ,
reported 9091.8% continence rates at a 12-month follow - up assessment . in our study , the first 100 patients had a slightly lower pad - free rate , but this rate gradually improved .
the increase in continence rates observed with surgical experience was statistically significant , and we speculate that similar results can be achieved after 50 cases .
additionally , another reason for the low continence rate was that the age of the patients was higher . similarly , several high - volume series have reported potency rates of 7078% at 12 months after ralp [ 17 , 18 , 29 , 32 ] .
although we observed relatively good outcomes , these outcomes are difficult to analyze because of both the small number of cases who underwent nerve - sparing lrp ( total : 65 patients ) as well as the preoperative low international index of erectile function ( iief-5 ) score ( preoperative : 11.3  8.1 points , range : 022 ) . in this study , 8 surgeons were responsible for the 300 cases .
although each surgeon had prior experience with more than 50 cases of lrp , each had limited prior experience with ralp .
however , we conclude that the ralp procedure is easier to learn than lrp because , with only 300 cases , the surgeons were able to achieve levels of positive outcomes that are similar to those reported in the literature .
the da vinci system used at our institution was the 15th such system installed in japan ; 120 japanese hospitals have now adopted the use of this system .
the rate of ralp operations had been low in japan , as well as in other developing countries .
prior to april 2012 , ralp procedures were not covered by japanese health insurance companies and this is believed to have influenced the lack of widespread use of this procedure in japan . with its proven advantages and the increasing skills of the surgeons , this technology is likely to gain further acceptance in the near future .
however , a decrease in the cost of robotic surgical systems is essential for continued feasibility of this technique . for any new treatment modality to gain widespread global acceptance , the outcomes need to be reproducible across various centers and patient populations .
although ralp is a validated treatment option for the management of patients with localized prostate cancer , all prior reports have come from high volume centers in western countries .
this study showed good perioperative outcomes for ralps in the initial 300 cases performed at our facility .
surgical , oncologic , and functional outcomes all improved with increasing surgical experience , following a relatively short learning curve after transitioning from lrp . after the first 300 ralp cases , outcomes were similar to those reported at high - volume medical centers .
 
 background . 
 the goal of this study was to analyze the perioperative outcomes of robot - assisted laparoscopic radical prostatectomies ( ralps ) performed at our center . methodology . 
 we retrospectively reviewed 300 consecutive patients with clinically localized prostate cancer who underwent ralp with a posterior dissection approach to the seminal vesicle between may 2011 and november 2013 . 
 the mean patient age was 67.2  5.5 years ( range : 4178 years ) , and the mean prostate - specific antigen ( psa ) concentration , at diagnosis of prostate cancer , was 9.16  6.50  ng / ml ( range : 2.2055.31  ng / ml ) . 
 results . 
 the median duration of robotic surgery was 160  min ( mean : 165  40  min ; range : 75345  min ) . 
 median estimated blood loss , including that in urine , was 200  ml ( mean : 277  324  ml ; range : 43250  ml ) . 
 intraoperative and immediate postoperative complications occurred in 3.0% of patients ; 4 patients required allogeneic blood transfusion . as a measure of patient continence 
 , 82.4% did not use more than 1 absorbent pad in 24  h , at 6 months postoperatively . 
 conclusion . 
 ralp with an initial posterior dissection to the seminal vesicle was a safe and efficient method for controlling prostate cancer , even in these initial cases . 
1. Introduction
2. Materials and Methods
3. Results
4. Discussion
5. Conclusion