lower urinary tract symptoms ( luts ) are a common problem affecting old men , and the prevalence of luts related to benign prostatic hyperplasia ( bph ) increases with age , approaching 50% by the age of 60 years and 90% by the age of 85 years .
treatment strategies include watchful waiting , medical therapy , and surgery . with the increase in the aging population worldwide
although transurethral resection of the prostate ( turp ) remains the gold standard surgical technique , the evolution of minimally invasive surgical options has challenged turp .
these newer options have the potential for decreased morbidity in older patients who have medical comorbidities .
an example is potassium - titanyl - phosphate ( ktp ) laser photoselective vaporization prostatectomy ( pvp ) .
laser prostatectomy was developed to reduce the complications and costs associated with turp in the treatment of luts secondary to bph .
al - ansari et al .   showed that 120 w greenlight laser pvp is a safe and effective treatment for patients suffering from bph in comparison with the gold standard treatment of turp .
the average duration of catheterization was 1.4 days for the pvp group and 2.7 days for the turp group .
the average time of hospital stay was significantly shorter in the pvp group ( 4.1 days vs. 2.3 days for the turp and pvp groups , respectively ) . with the growing aging population , the risk of developing postoperative complications and he extended catheter indwelling time resulting in a prolonged hospital stay directly impact our health care provision .
the interval to catheter removal following turp is variable , ranging from 24 hours   to 5 days .
previous studies have tried to determine the variables responsible for early catheter removal after transurethral resection , so that catheters could be removed earlier without increasing morbidity , thus reducing the length of hospital stay and ultimately leading to savings in the health care budget .
it is evident that the average duration of catheter indwelling is shorter in patients undergoing pvp than in those undergoing turp , but no study has yet been conducted on the risk factors associated with failure of catheter removal on postoperative day 1 .
the purpose of this study was therefore to analyze the risk factors for failure of early catheter removal after 120 w greenlight laser pvp in bph patients on the basis of the experience of a single institute .
, 469 consecutive patients with luts secondary to bph were treated with 120 w greenlight laser pvp .
the inclusion criteria were the presence of moderate to severe luts , failed previous medical therapy , and bph - associated complications , such as hematuria , recurrent urinary tract infections , and urinary retention .
a total of 427 patients were selected for the present study , excluding patients who underwent surgery owing to urethral stricture or who used urethral catheters on a long - term basis .
patients were also excluded if they had evidence of neurogenic bladder disorder , bladder or prostatic malignancy , or a history of prostate surgery .
the presence of a large median lobe , patient age , and the use of anticoagulants were not criteria for exclusion .
all patients were assessed with a complete medical history , physical examination , international prostate symptom score ( ipss ) , maximum urinary flow rate ( qmax ) , postvoid residual volume ( pvr ) , transrectal ultrasonography ( trus ) , prostate - specific antigen ( psa ) , complete blood cell count including hemoglobin , urine analysis , and urodynamic study .
regarding the medical history of the subjects , the presence of preoperative urinary retention was investigated , as was the presence of comorbidities such as diabetes mellitus ( dm ) , hypertension , cardiovascular disease , and coronary artery diseases . if patients were found to have an elevated serum psa value ( > 4 ng / ml ) or abnormal findings on a digital rectal examination , they underwent concomitant transrectal prostate needle biopsy to exclude prostate cancer .
urodynamic investigations and evaluations were performed according to the standards recommended by the international continence society . the bladder outlet obstruction index ( booi ) and the bladder contractility index ( bci )
were calculated by urodynamic study by use of the following formulas : ( pdetqmax , detrusor pressure at maximum flow rate ) pvp was performed by a single urologist , and all procedures were carried out under general or spinal anesthesia . a continuous running irrigation system 22 fr resectoscope and a laser fiber were used . the 120 w hps laser system ( laserscope , greenlight , american medical systems , minnetonka , mn , usa ) was used , and all prostate tissue causing obstruction was removed until a fine surgical cavity was formed , as in turp .
an 18 fr urethral catheter was placed after the operation and irrigation with saline solution was begun in the operating room . when the patients recovered from anesthesia and if the urine was clear , irrigation was stopped .
if patients were unable to urinate , a urethral catheter was replaced before hospital discharge and the patient was returned to our outpatient clinic for a second voiding trial .
the perioperative variables , including operative time , amount of applied energy , catheterization time , and any intraoperative or postoperative complications , were recorded .
patients were divided into two groups : patients with successful urination after urethral catheter removal on postoperative day 1 , and patients in whom a catheter was reinserted after urethral catheter removal on postoperative day 1 owing to urinary retention .
the descriptive statistics are presented as meanstandard deviation , and variables were analyzed with the mann - whitney test , chi - square test , and logistic regression analysis by use of spss ver .
. catheters were successfully removed in 378 ( 88.6% ) patients on postoperative day 1 .
catheters were reinserted in a total of 49 patients owing to unsuccessful urination , and the catheters were removed at a mean of 6.450.39 days postoperatively .
the percentage of patients with a history of preoperative urinary retention in the successful urination group and the catheter reinsertion group was 16.9% and 28.6% , respectively , and thus was significantly higher in the catheter reinsertion group ( p<0.05 ) . in terms of comorbidities ,
differences in the ratios of hypertension , cardiovascular disease , and coronary artery disease were not significant , whereas the ratio of dm was 15.3% and 28.6% in the successful urination group and the catheter reinsertion group , respectively ( p<0.05 ) .
preoperative prostate volume was about 48 ml , which was not significantly different between the groups , and the differences in ipss and quality of life scores were also not significant .
in the urodynamic evaluation , the catheter reinsertion group showed a lower qmax , higher pvr , and more obstructive and weak contractile patterns than did the successful urination group , but these differences were not statistically significant .
the mean operative time was significantly shorter in the early catheter removal group ( p<0.05 ) . in terms of lasing time and amount of applied energy ,
no significant differences were observed between the groups . in the univariate analysis of the variables , we noticed that history of dm , history of urinary retention , and longer operative time were statistically significant predictors of failure of early catheter removal .
history of dm was found to be the most significant predictor ( p=0.028 ) , followed by operative time ( p=0.039 ) ( table 3 ) .
there were no significant differences in age , prostate volume , ipss , or urodynamic parameters between the two groups .
turp has been regarded as the gold standard surgical treatment of bph . in an attempt to overcome the limitations and morbidities of turp
ktp laser pvp and , subsequently , greenlight hps laser pvp are such alternatives , with a large body of clinical evidence . in a comparison of greenlight laser pvp with turp , the outcome parameters were significantly improved compared with preoperative values , with no significant differences between the two groups . however , patients undergoing turp experienced more severe adverse effects than did pvp patients , thus giving the latter a more favorable perioperative safety profile . performing conventional turp in patients who are on oral anticoagulant therapy
has a high complication rate , with a transfusion rate of 30% ; however , pvp laser treatment has been successfully used in patients on anticoagulant therapy .
if catheter indwelling or transfusion is required owing to bleeding , the duration of postoperative hospitalization is extended .
therefore , compared with turp , the decrease in development of complications with pvp laser treatment contributes to a shortened hospital stay .
studies have reported that early catheter removal reduces the length of the hospital stay , which in turn would be beneficial to health care costs .
in addition to cost savings , early catheter removal and early discharge may have advantages , especially for patients for whom an early return to their employment is required . in our study ,
88.6% were catheter - free on postoperative day 1 and were discharged home on the same day .
the mean duration of indwelling catheterization , 1.63 days , was similar to other reports . however , no study that analyzed risk factors in patients whose urethral catheters were not removed on postoperative day 1 has previously been reported . in the case of turp ,
nakagawa and toguri   suggested risk factors such as age , postoperative bleeding , and several comorbidities , including coronary heart disease , renal insufficiency , and alzheimer 's disease .
reported that a history of acute urinary retention does not affect the duration of catheter indwelling after the turp procedure . in the case of greenlight
hps laser pvp , patients are discharged after removal of the catheter within 24 hours after surgery and a voiding trial if postoperative complications do not develop . however ,
if voiding is unsuccessful , patients are discharged with the catheter reinserted or the hospital stay is extended for a few more days .
if a patient has risk factors for difficulty with early postoperative voiding , it would be preferable to discharge the patient on postoperative day 1 with the catheter to save on cost and to reduce the pain caused by repeated catheter insertions . in studies on turp , clot retention caused by postoperative bleeding
was suggested as a major risk factor . in the case of pvp laser treatment ,
the matter is of little importance , because the risk of developing complications such as clot retention is considered very low .
according to the present study , there was a significant difference in the presence of a history of urinary retention between the groups , but in the multivariate analysis , no difference was observed . instead , history of dm and longer operative time were confirmed as significant risk factors .
dm cystopathy is traditionally described as a triad of decreased sensation , increased capacity , and poor emptying , but many inconsistencies have been found in those classic findings . a review by kaplan et al .  
of urodynamic findings in 182 diabetes cases revealed that 55% had detrusor overactivity with 10% areflexic and 11% indeterminate .
therefore , symptoms of bladder dysfunction may not be detected in an early stage of dm , but even after bph is solved , voiding difficulty may remain . a continuous running irrigation system can help to secure a clear view during surgery but may result in consistent bladder distension . because the duration of surgery is prolonged , the duration of bladder distension is also extended , and increased fatigability of the detrusor muscle is considered to result in temporary bladder dysfunction .
the limitations of the present study include the following : limited analysis of risk factors owing to insufficient numbers of subjects , lack of confirmation of increased costs resulting from the extended catheter indwelling time , and lack of confirmation of differences in functional outcomes between the two groups after several postoperative months . through multi - institutional study in the future with more data , the correlation between the period of catheter indwelling and total costs and the risk factors affecting the period of catheter indwelling may be confirmed .
then , the advantages of the fewer complications of pvp laser compared with turp will be understood more clearly .
it is feasible , safe , and cost - effective to remove the urethral catheter on postoperative day 1 after greenlight hps laser pvp , but it should be done carefully in patients with a history of dm or in those who experienced an extended operative time .
 purposeto assess the risk factors for developing urinary retention after removal of the urethral catheter on postoperative day 1 in benign prostatic hyperplasia patients who underwent greenlight hps laser photoselective vaporization prostatectomy ( pvp).materials and methodsthe study included 427 men who underwent greenlight hps laser pvp between 2009 and 2012 , excluding patients in whom a catheter was maintained for more than 1 day because of urethral procedures . 
 in all patients , a voiding trial was performed on postoperative day 1 ; if patients were unable to urinate , the urethral catheter was replaced before hospital discharge . 
 the patients were divided into two groups : early catheter removal ( postoperative day 1 ) and late catheter removal ( urethral catheter reinsertion ) . 
 preoperative and perioperative parameters were compared between the groups.resultscatheters were successfully removed in 378 ( 88.6% ) patients on postoperative day 1 . in 49 patients , 
 the catheters were reinserted and removed a mean of 6.450.39 days after surgery . in a multivariate analysis , 
 a history of diabetes was the most significant predictor ( p=0.028 ) of failure of early catheter removal , followed by operative time ( p=0.039 ) . 
 there were no significant differences in age , prostate volume , international prostate symptom score , or urodynamic parameters between the two groups.conclusionsit is feasible , safe , and cost - effective to remove the urethral catheter on postoperative day 1 after greenlight hps laser pvp , but the procedure should be done carefully in patients who have history of diabetes or an extended operative time . 
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
CONCLUSIONS