International Journal of Urology | 2019
Predictive factors of improvement for voiding symptoms after holmium laser enucleation of the prostate
Abstract
DOI: 10.1111/iju.13825 HoLEP has become a major surgical procedure for BPH. The present study examined how three factors, preoperative prostate volume, resected prostate weight and resected prostate ratio (resected prostate weight/preoperative prostate volume), affected voiding symptoms after HoLEP. We examined 614 consecutive patients with available data for analysis who underwent HoLEP in 2006–2017 in five hospitals including Kobe University Hospital, Kobe, Japan. The patients with urethral stenosis, neurogenic bladder or operative history of BPH were excluded. We defined improvement of Qmax as postoperative UFM ≥15 mL/s, and that of postoperative residual urine volume as ≤50 mL, and statistically investigated how factors such as preoperative prostate volume, resected prostate weight and resected prostate ratio (resected prostate weight/preoperative prostate volume) affected voiding symptoms after HoLEP. Preoperative prostate volume was estimated by using prolate ellipse volume = (length 9 width 9 height) 9 p / 6 with ultrasonography. We evaluated symptoms 3 months after HoLEP. Statistical analysis was carried out by Student’s t-test using StatView 5.0 software (Abacus Concepts, Berkley, CA, USA). Statistical significance was established at the level of P < 0.05. This study was approved by the institutional review board of the Kobe University Graduate School of Medicine. Patients’ backgrounds are shown in Table S1. Preoperative residual urine was 120.90 130.38 mL. A total of 39 patients with preoperative Qmax ≥15 mL/s on UFM were excluded from the evaluation of improved or unimproved voiding symptoms, and moreover, 366 patients with ≥50 mL preoperative residual urine volume were evaluated for residual urine. Using our definition of improved voiding symptoms above, improved UFM was accomplished in 347 of 575 (60.3%) patients, and residual volume was improved in 338 of 366 (92.3%) after HoLEP. Our statistical data showed three potential factors related to voiding symptoms: (i) preoperative prostate volume; (ii) resected prostate weight; and (iii) prostatic resected ratio significantly correlated with improvement of UFM (improved group: 72.20 35.53 mL and unimproved group: 64.70 35.43 mL, P = 0.0135, r = 0.142; 41.50 25.75 g and 32.80 22.54 g, P ≤ 0.0001, r = 0.180; and 56.47 21.48% and 52.40 26.58%, P = 0.0446, r = 0.063, respectively; Table 1). As for those cases with preoperative Qmax of ≤15 mL/s, the relationship between the preoperative prostate volume, not residual urine, and change of Qmax after HoLEP was a linear correlation (correlation coefficient 0.7389; Fig. S1). This suggests that preoperative prostate volume was associated with the amount of change of Qmax. There are several studies of potential factors contributing to the improvement of voiding symptoms after HoLEP. Ryoo et al. focused on IPSS/QOL and Qmax on UFM, finding that ≥40 of the BOOI (BOOI = PdetQmax 2Qmax) rather than prostate volume significantly correlated with the success of HoLEP. Cho et al. showed that the absence of DU, the presence of BOO and higher IPSS are significant factors for HoLEP success. Another study showed preoperative IPSS and the number of metabolic syndromes significantly correlated with improvements after HoLEP. Lee et al. showed that a higher IPSS voiding score and higher QOL score were found after HoLEP. Woo et al. stated the weight of the resected prostate contributed to improving postoperative Qmax and post-void residual urine volume. 7 Mu et al. reported that the operation for BPH >70 mL improved the functional outcome. We showed a prostate volume of 72.20 35.53 mL with the UFM improvement group. Furthermore, we suggest one possible interpretation of the minimal difference of 6 mL between the improved and unimproved group is not only prostate volume, but other factors, such as bladder function. Taken together, the present data showed that preoperative prostate volume, resected prostate weight and resected prostate ratio were significant factors for improvement of voiding symptoms. We would use these data for deciding the indication of HoLEP from those of preoperative UFM and residual volume. We would like to emphasize the study limitations. First, the number of surgeons was much higher than other studies where only one or two surgeons were involved. The variation in