Robot-assisted intracorporeal ileal conduit urinary diversion: A two-center comparative study of Bricker versus Wallace ureteroileal anastomosis.

INTRODUCTION: This study was performed to evaluate the differences in the perioperative results, renal function, and incidence of hydronephrosis over time between the use of Bricker anastomosis and Wallace anastomosis for robot-assisted intracorporeal ileal conduit urinary diversion (RICIC). METHODS: Fifty-five patients who underwent RICIC at two institutions were evaluated (Bricker, n = 23; Wallace, n = 32). We investigated changes in estimated glomerular filtration rate and hydronephrosis before surgery and at 3, 6, and 12 months after surgery. RESULTS: The patients in the Bricker group were significantly older than those in the Wallace group. The urinary diversion time was significantly longer in the Bricker group. No significant difference in postoperative renal function was observed. Additionally, no significant difference was observed in the incidence of postoperative hydronephrosis. However, the incidence of right hydronephrosis tended to be high overall, especially in the Wallace group. No patients in either group required repair surgery or ureteral stent placement. CONCLUSIONS: In patients undergoing RICIC, there was no difference in postoperative renal function or the incidence of hydronephrosis between Wallace and Bricker anastomosis. Symptomatic hydronephrosis was not observed in either group. The present study showed that each method was equally effective and safe.

Impact of lymph node dissection on surgical and oncological outcomes in patients undergoing robot-assisted radical cystectomy for bladder cancer: a multicenter retrospective study.

This study was performed to clarify the therapeutic and diagnostic roles of lymph node dissection (LND) by examining the impact of LND and lymph node yield (LNY) on oncological outcomes in patients undergoing robot-assisted radical cystectomy (RARC). Between 2014 and 2021, 216 patients underwent LND during RARC at Tokushima University Hospital and affiliated hospitals. Among the 216 patients, we compared 115 patients with an LNY of ≥ 20 and 101 with an LNY of < 20 to investigate the impact of LNY on surgical and oncological outcomes. Furthermore, we investigated the impact of LNY and the extent of LND on oncological outcomes by dividing the extent of LND into two groups (standard and extended). The 3-year rates of overall survival (OS) (p = 0.256), cancer-specific survival (CSS) (p = 0.791), and recurrence-free survival (RFS) (p = 0.953) did not differ between the two groups divided by the LNY. A higher LNY was associated with a significantly higher lymph node positivity rate (p = 0.020). The incidence of LND-related major complications was not significantly different between the two groups (p = 0.910). The 3-year survival rates did not differ between the two groups divided by the extent of LND: OS (p = 0.366), CSS (p = 0.814), and RFS (p = 0.689). The LNY and extent of LND were not associated with oncological outcomes in patients undergoing LND during RARC, whereas a higher LNY was associated with lymph node positivity. In the era of adjuvant therapy with immune checkpoint inhibitors, LND during RARC has an important diagnostic role in the detection of pathological node positivity.

Peripheral neuropathy and nerve electrophysiological changes with enfortumab vedotin in patients with advanced urothelial carcinoma: a prospective multicenter cohort study.

BACKGROUND: Enfortumab vedotin is a novel antibody-drug conjugate used as a third-line therapy for the treatment of urothelial cancer. We aimed to elucidate the effect of enfortumab vedotin-related peripheral neuropathy on its efficacy and whether enfortumab vedotin-induced early electrophysiological changes could be associated with peripheral neuropathy onset. METHODS: Our prospective multicenter cohort study enrolled 34 patients with prior platinum-containing chemotherapy and programmed cell death protein 1/ligand 1 inhibitor-resistant advanced urothelial carcinoma and received enfortumab vedotin. The best overall response, progression-free survival, overall survival, and safety were assessed. Nerve conduction studies were also performed in 11 patients. RESULTS: The confirmed overall response rate and disease control rate were 52.9% and 73.5%, respectively. The median overall progression-free survival and overall survival were 6.9 and 13.5 months, respectively, during a median follow-up of 8.6 months. The patients with disease control had significantly longer treatment continuation and overall survival than did those with uncontrolled disease. Peripheral neuropathy occurred in 12.5% of the patients. The overall response and disease control rates were 83.3% and 100%, respectively: higher than those in patients without peripheral neuropathy (p = 0.028 and p = 0.029, respectively). Nerve conduction studies indicated that enfortumab vedotin reduced nerve conduction velocity more markedly in sensory nerves than in motor nerves and the lower limbs than in the upper limbs, with the sural nerve being the most affected in the patients who developed peripheral neuropathy (p = 0.011). CONCLUSION: Our results indicated the importance of focusing on enfortumab vedotin-induced neuropathy of the sural nerve to maximize efficacy and improve safety.

Prognostic impact of histological discordance between transurethral resection and radical cystectomy.

OBJECTIVE: To analyse the impact of histological discordance of subtypes (subtypes or divergent differentiation [DD]) in specimens from transurethral resection (TUR) and radical cystectomy (RC) on the outcome of the patients with bladder cancer receiving RC. PATIENTS AND METHODS: We analysed data for 2570 patients from a Japanese nationwide cohort with bladder cancer treated with RC between January 2013 and December 2019 at 36 institutions. The non-urinary tract recurrence-free survival (NUTR-FS) and overall survival (OS) stratified by TUR or RC specimen histology were determined. We also elucidated the predictive factors for OS in patients with subtype/DD bladder cancer. RESULTS: At median follow-up of 36.9 months, 835 (32.4%) patients had NUTR, and 691 (26.9%) died. No statistically significant disparities in OS or NUTR-FS were observed when TUR specimens were classified as pure-urothelial carcinoma (UC), subtypes, DD, or non-UC. Among 2449 patients diagnosed with pure-UC or subtype/DD in their TUR specimens, there was discordance between the pathological diagnosis in TUR and RC specimens. Histological subtypes in RC specimens had a significant prognostic impact. When we focused on 345 patients with subtype/DD in TUR specimens, a multivariate Cox regression analysis identified pre-RC neutrophil-lymphocyte ratio and pathological stage as independent prognostic factors for OS (P = 0.016 and P = 0.001, respectively). The presence of sarcomatoid subtype in TUR specimens and lymphovascular invasion in RC specimens had a marginal effect (P = 0.069 and P = 0.056, respectively). CONCLUSION: This study demonstrated that the presence of subtype/DD in RC specimens but not in TUR specimens indicated a poor prognosis. In patients with subtype/DD in TUR specimens, pre-RC neutrophil-lymphocyte ratio and pathological stage were independent prognostic factors for OS.

A case of an advanced renal collecting duct carcinoma in which initial therapeutic effect was achieved with pembrolizumab plus axitinib.

Introduction: Renal collecting duct carcinoma is often found in advanced cancers and has a poor prognosis. Here, we present the case of symptomatic metastatic collecting duct carcinoma in which we observed an initial therapeutic effect of immune checkpoint inhibitors plus tyrosine kinase inhibitors. Case presentation: The patient was a 69-year-old male who was referred to our hospital for examination of a right chest tumor and related pain. Contrast-enhanced computed tomography and tumor biopsy were performed, leading to a diagnosis of collecting duct carcinoma. A combination of pembrolizumab plus axitinib was initiated as first-line therapy; right chest pain decreased, and tumor shrinkage was observed. Seven months after treatment initiation, tumor progression was noted. Cabozantinib was initiated as second-line therapy; however, was discontinued due to patient fatigue. The patient died 15 months after the initiation of treatment. Conclusion: For symptomatic metastatic collecting duct carcinoma, pembrolizumab plus axitinib may have initial therapeutic effects.

Real-world prostate-specific antigen response and progression to castration-resistant prostate cancer among men with metastatic castration-sensitive prostate cancer treated with apalutamide: a multi-institutional study in the Chu-shikoku Japan Urological Consortium.

BACKGROUND: Japanese men receiving apalutamide often experience skin-adverse events (AEs), possibly requiring treatment interruption or dose reduction. However, concerns have arisen regarding the impact of these adjustments on the efficacy of apalutamide. Our study evaluated the efficacy, safety, and persistence of apalutamide in men with metastatic castration-sensitive prostate cancer (mCSPC). METHODS: We retrospectively reviewed the medical records of 108 men with mCSPC from 14 Japanese institutions. The primary outcomes were the efficacy of apalutamide: prostate-specific antigen (PSA) response (50%, 90% and < 0.2 decline) and progression to castration-resistant prostate cancer (CRPC). The secondary outcomes were the skin-AE and compliance of apalutamide. RESULTS: PSA50%, PSA90% and PSA < 0.2 declines were observed in 89.8, 84.3 and 65.7%, and the median time to CRPC progression was not reached. PSA < 0.2 decline and an initial full dose of apalutamide were significantly associated with a longer time to CRPC. The most common AE was skin-AE (50.9%), and there was no association between the occurrence of skin-AE and the time to CRPC (P = 0.72). The median apalutamide persistence was 29 months, which was longer in the initial full dose recipients than in the reduced dose recipients. The dosage is reduced in about 60% of patients within the first year of treatment in the initial full dose recipients. CONCLUSIONS: Our findings indicate the effectiveness of apalutamide in Japanese men with mCSPC, despite a substantial portion requiring dose reduction within a year among the initial full dose recipients.

The importance of laparoscopic surgery for young urologists remains unwavering even in the era of robot-assisted surgery.

Robot-assisted surgery (RAS) cannot be achieved without the performance of laparoscopic surgical techniques by a patient-side surgeon (PSS). In many medical institutions in Japan, young urologists often take on the role of a PSS. Participating in RAS as a PSS provides a good opportunity to acquire not only the knowledge necessary for surgery, but also skills in laparoscopic surgical techniques. Learning laparoscopic surgery as a PSS may contribute to improving the quality of RAS. Furthermore, it will lead to skill improvement as an operator in laparoscopic surgery. However, notably, opportunities for young urologists to perform laparoscopic surgery are decreasing in the current era of RAS. Under these circumstances, we believe that cadaver surgical training will become increasingly important in the future. We believe that performance of cadaver surgical training will contribute to increased motivation, enhance the understanding of surgical procedures, and facilitate the acquisition of surgical techniques.

Effect of Positive Biopsy Core Rate on Low-dose-rate Brachytherapy Outcomes in Intermediate-risk Prostate Cancer.

BACKGROUND/AIM: Intermediate-risk prostate cancer (PCa) is a highly heterogeneous disease. Although low-dose-rate brachytherapy (LDR-BT) is mainly used for low- to intermediate-risk PCa, limited reports have evaluated the detailed differences in outcomes, including differences between patients with ISUP grade group (GG) 2 and GG3 intermediate-risk PCa. This study aimed to investigate the differences in outcomes between intermediate-risk Japanese patients with GG2 and GG3 PCa who underwent LDR-BT. PATIENTS AND METHODS: This single-center retrospective study included 342 consecutive patients with intermediate-risk PCa; 232 patients with GG2 and 110 with GG3 were treated with LDR-BT at Tokushima University Hospital between July 2004 and December 2019. RESULTS: No significant difference in 5-year biochemical progression-free survival and cancer-specific survival was observed between patients with GG2 and those with GG3 (p=0.649 and p=0.633, respectively). Multivariate analysis showed that radiation doses up to 90% of the prostate volume (D90) and the percentage of positive cores were predictors of recurrence in all patients with intermediate-risk PCa. Group analyses showed that D90 was a predictor for recurrence in patients with GG2. In contrast, a high percentage of positive cores was a significant risk factor for recurrence in patients with GG3. CONCLUSION: Positive core ratios observed on prostate biopsy correlated with higher recurrence rates after LDR-BT. This indicates that the proportion of positive cores in the biopsy may be an important factor in predicting the likelihood of recurrence, especially for patients with GG3 PCa.

Lymph node dissection during radical cystectomy for bladder cancer: A two-center comparative study of robotic versus open surgery.

INTRODUCTION: This study was performed to evaluate the safety and efficacy of lymph node dissection (LND) during robot-assisted radical cystectomy (RARC) compared with open radical cystectomy (ORC). METHODS: From October 2003 to December 2021, 122 patients underwent LND during RARC and 103 patients underwent LND during ORC at Tokushima University Hospital and Tokushima Prefectural Central Hospital. We investigated the safety and efficacy of LND during RARC by comparing the surgical and oncological outcomes between the two groups. RESULTS: The patients were significantly older in the RARC than the ORC group. The operative time was significantly shorter and the estimated blood loss was significantly lower in the RARC than the ORC group. Although the lymph node yield was significantly higher in the RARC than the ORC group, there was no significant difference in lymph node positivity between the groups. There was no significant difference in the incidence of local recurrence or distant metastasis between the two groups. The 5-year survival rates (overall survival, cancer-specific survival, and recurrence-free survival) were not different between the RARC and ORC groups. CONCLUSION: This study suggests that the surgical and oncological safety and efficacy of LND during RARC are greater than those of LND during ORC. We believe that LND during RARC is a higher-quality procedure than LND during ORC.

Insulin receptor expression to predict resistance to axitinib and elucidation of the underlying molecular mechanism in metastatic renal cell carcinoma.

BACKGROUND: The study aimed to examine the significance of insulin receptor (INSR) expression in predicting resistance to axitinib in clear cell renal cell carcinoma (ccRCC). METHODS: Clinicopathological data were collected from 36 consecutive patients with metastatic RCC who received axitinib. Thirty-three primary tumours were obtained for immunohistochemistry. Patient-derived xenograft (PDX) models were created by transplanting primary tumours into immunodeficient mice, establishing axitinib-resistant PDX models. RCC cell lines were co-cultured with human renal glomerular endothelial cells (HGECs) treated with siRNA of INSR (HGEC-siINSR). Gene expression alteration was analysed using microarray. RESULTS: The patients with low INSR expression who received axitinib had a poorer outcome. Multivariate analysis showed that INSR expression was the independent predictor of progression-free survival. INSR expression decreased in axitinib-resistant PDX tumours. RCC cell lines showed upregulated interferon responses and highly increased interferon-ß levels by co-culturing with HGEC-siINSR. HGECs showed decreased INSR and increased interferon-ß after axitinib administration. RCC cell lines co-cultured with HGEC-siINSR showed high programmed death-ligand 1 (PD-L1) expression, which increased after interferon-ß administration. CONCLUSIONS: Decreased INSR in RCC could be a biomarker to predict axitinib resistance. Regarding the resistant mechanism, vascular endothelial cells with decreased INSR in RCC may secrete interferon-ß and induce PD-L1.

The impact of nutritional status and changes of body composition on the prognosis of metastatic renal cell carcinoma patients.

PURPOSE: This study aimed to analyze the impact of patients' nutritional status and changes in body composition on the prognosis of metastatic renal cell carcinoma (mRCC) patients who received systemic therapy with tyrosine kinase inhibitors (TKIs). METHODS: A total of 57 mRCC patients who received systemic therapy with TKIs as first-line therapy at our facility between November 2004 and October 2018 were included. The Prognostic Nutritional Index (PNI) was used to evaluate their nutritional status. The volumes of skeletal muscle mass and fat tissue were calculated using the SYNAPSE VINCENT system. The effects of nutritional status and body composition of mRCC patients on progression-free survival (PFS) and overall survival (OS) were analyzed using Cox regression methods. RESULTS: Low PNI at the start of systemic therapy was a significant prognostic predictor for OS (HR 3.807 [95% CI 1.205-12.027], P=0.046), and it was related to loss of muscle mass three months after systemic therapy. Although the loss of muscle mass at the start of systemic therapy was not associated with OS, loss of muscle mass during treatment predicted worse OS. CONCLUSIONS: Nutritional status of mRCC patients may predict changes in body composition and be associated with their prognosis. J. Med. Invest. 70 : 80-87, February, 2023.

Prostate-specific Antigen Levels Following Brachytherapy Impact Late Biochemical Recurrence in Japanese Patients With Localized Prostate Cancer.

BACKGROUND/AIM: Evaluation of long-term outcomes is essential for the successful treatment of localized prostate cancer; however, the risk of late recurrence following brachytherapy is still not clear. This study aimed to evaluate the long-term outcomes of low-dose-rate brachytherapy (LDR-BT) for localized prostate cancer in Japanese patients and identify factors associated with late recurrence after treatment. PATIENTS AND METHODS: This single-center, cohort study included patients who underwent LDR-BT at the Tokushima University Hospital in Japan between July 2004 and January 2015; 418 patients, who were followed-up at least 7 years after LDR-BT, were included in the study. Biochemical progression free survival (bPFS) was defined according to the Phoenix definition (nadir PSA+2 ng/ml) and bPFS and cancer specific survival (CSS) were calculated using Kaplan-Meier survival curves. Univariate and multivariate analyses were performed using Cox proportional hazard regression models. RESULTS: Approximately half of the patients with PSA >0.5 ng/ml at 5 years after LDR-BT had a recurrence within the next 2 years. However, only 1.4% of the patients with a PSA ≤0.2 ng/ml at 5 years post-treatment showed tumor recurrence, including those at high risk of treatment failure according to the D'Amico classification. In multivariate analysis, PSA level at 5 years post-treatment was the only predictor of late recurrence after 7 years of treatment. CONCLUSION: PSA levels at 5 years post-treatment were associated with long-term recurrence of localized prostate cancer, which can help alleviate patient anxiety concerning prostate cancer recurrence if PSA levels remain low at 5 years after LDR-BT.

Assistent guide: A novel device for ureteral stent placement in robot-assisted intracorporeal ileal conduit.

INTRODUCTION: Ureteral stent placement in robot-assisted intracorporeal ileal conduit formation (RICIC) is more challenging than extracorporeal urinary diversion. We developed a novel dedicated device called the Assistent guide for safe and smooth performance of ureteral stent placement by the patient-side surgeon (PSS). METHODS: This study reviewed the clinical records of 59 patients underwent RICIC with a total of 110 ureteral stent placements: 59 stents were placed using the Assistent guide, and 51 stents were placed using a suction tip. RESULTS: The stenting time was significantly shorter in the Assistent guide group than in the suction tip group. Even for beginners, the stenting time was significantly shorter. The PSSs' satisfaction score was significantly higher in the Assistent guide group. No complications associated with ureteral stent placement occurred. CONCLUSIONS: We showed the safety and efficacy of the Assistent guide for ureteral stent placement in RICIC.

Recurrent multiple liver metastases of clear cell renal cell carcinoma with a significant response to sunitinib after nivolumab treatment.

Introduction: A case of multiple liver metastases of clear cell RCC with a significant response to sunitinib as the fifth line after nivolumab is reported. Case presentation: The patient was a 65-year-old man who underwent open nephrectomy for RCC. After the nephrectomy, he had recurrences several times, and metastasectomy had been performed for each recurrence. At 13 years after the nephrectomy, multiple liver, and lung metastases appeared. The treatment was switched to axitinib, followed by cabozantinib, then nivolumab. The best response was PR, SD, and PD for these three drugs, and treatment duration was 14, 3, and 3 months, respectively. As the fifth line, sunitinib was administered, with significant shrinkage of the multiple liver metastases, and PR has been maintained for 34 months. Conclusion: Sunitinib after an IO-drug showed a significant effect in spite of only slight efficacy with other VEGFR-TKIs, which may have occurred through the alteration of the immunological microenvironment.

Efficacy of the Mercedes-Benz closure technique for vaginal reconstruction in female robot-assisted radical cystectomy.

INTRODUCTION: Vaginal reconstruction using the posterior vaginal wall is required following radical cystectomy in women with resection of the uterus, adnexa, and anterior vaginal wall. Roll closure and clamshell closure are two widely known techniques. Of these, clamshell closure is recommended because roll closure has a high likelihood of breakdown or a resultant canal that is too narrow for sexual intercourse. In clamshell closure, however, folding the posterior vaginal wall anteriorly can be difficult. Therefore, we devised Mercedes-Benz closure, in which the vaginal wall is sutured from three directions to form a Mercedes-Benz shape, for anastomosis without tension on the vaginal wall. The present study was performed to investigate the efficacy of this alternative surgical technique for vaginal reconstruction. METHODS: Twenty-six patients who underwent vaginal reconstruction following robot-assisted radical cystectomy were divided into two groups: 15 underwent clamshell closure and 11 underwent Mercedes-Benz closure. The patients' characteristics and surgical outcomes were compared between the two groups. RESULTS: There were no significant differences in clinical characteristics, including age, body mass index, and prior abdominal surgery between the two groups. The median vaginal reconstruction time tended to be longer in the Mercedes-Benz closure group than in the clamshell closure group (35.0 vs. 27.0 min, p = 0.102). No complications associated with vaginal reconstruction were identified. CONCLUSION: The surgical outcomes were comparable between Mercedes-Benz closure and clamshell closure. If vaginal reconstruction with clamshell closure is difficult, Mercedes-Benz closure is a valuable alternative technique.

Effects of undernutrition and low energy availability on reproductive functions and their underlying neuroendocrine mechanisms.

It has been well established that undernutrition and low energy availability disturb female reproductive functions in humans and many animal species. These reproductive dysfunctions are mainly caused by alterations of some hypothalamic factors, and consequent reduction of gonadotrophin-releasing hormone (GnRH) secretion. Evidence from literature suggests that increased activity of orexigenic factors and decreased activity of anorexigenic/satiety-related factors in undernourished conditions attenuate GnRH secretion in an integrated manner. Likewise, the activity of kisspeptin neurons, which is a potent stimulator of GnRH, is also reduced in undernourished conditions. In addition, it has been suggested that gonadotrophin-inhibitory hormone, which has anti-GnRH and gonadotrophic effects, may be involved in reproductive dysfunctions under several kinds of stress conditions. It should be remembered that these alterations, i.e., promotion of feeding behavior and temporary suppression of reproductive functions, are induced to prioritize the survival of individual over that of species, and that improvements in metabolic and nutritional conditions should be considered with the highest priority.

A propensity score matching study on robot-assisted radical cystectomy for older patients: comparison of intracorporeal ileal conduit and cutaneous ureterostomy.

BACKGROUND: Robot-assisted radical cystectomy (RARC) and intracorporeal urinary diversion are less invasive than conventional procedures. However, for older patients, cutaneous ureterostomy (CUS) may be preferred because urinary diversion using the intestine has a high incidence of perioperative complications and is highly invasive. The purpose of this study was to demonstrate the safety and efficacy of intracorporeal ileal conduit (ICIC) compared with CUS in patients aged 75 years or older who underwent RARC. METHODS: From October 2014 to December 2021, 82 patients aged 75 years or older who underwent RARC at Tokushima University Hospital, Tokushima Prefectural Central Hospital, or Ehime Prefectural Central Hospital were retrospectively reviewed. Of these, 52 and 25 patients who underwent ICIC and CUS, respectively, were included. After adjusting the patients' characteristics using propensity score-matching, surgical results and prognoses were retrospectively compared. The propensity score was based on age, Eastern Cooperative Oncology Group Performance Status Scale (ECOG-PS), American Society of Anesthesiologists physical status classification (ASA-PS), clinical tumor stage, and neoadjuvant chemotherapy. RESULTS: The median age was lower in the ICIC group compared with the CUS group, and the proportion of high-risk cases (ECOG-PS ≥ 2 or ASA-PS ≥ 3) did not differ. The median operation time was longer in the ICIC group, and estimated blood loss was higher, compared with the CUS group. There were no significant differences in the incidence of complications within the first 30 postoperative days, incidence of complications 30-90 days after surgery, 2-year overall survival, 2-year cancer-specific survival, and 2-year recurrence-free survival. The stent-free rate was significantly lower in the CUS group than that in the ICIC group. CONCLUSION: In older patients, the ICIC group showed non-inferior surgical and oncological outcomes compared with the CUS group. Urinary diversion following RARC in older patients should be carefully selected by considering not only the age but also the general condition (including comorbidities) of the patient.

Clinical application of virtual imaging guided Robot-assisted partial nephrectomy.

Objectives : To evaluate whether virtual partial nephrectomy images could help surgeons identify vascular and collecting system around tumors during actual surgery. Materials & methods : We retrospectively analyzed 36 patients who underwent robot-assisted partial nephrectomy (RAPN) between 2016 and 2017. Virtual partial nephrectomy images were created from preoperative CT images using computer software, and then analyzed. For analysis, blood vessels and collecting system portions within a 5-mm-thick safety margin around the tumor were examined. During analysis, we predicted whether targeted vasculature around the tumor would require clipping or suturing during surgery, and also whether the collecting system would require opening during resection. Surgical outcomes for virtual partial nephrectomy analyses and actual RAPNs were compared and analyzed for sensitivity and specificity. Results : In 36 cases, 119 arteries and 100 veins were targeted on virtual partial nephrectomy images. Arterial suturing or clipping for hemostasis showed a sensitivity and specificity of 83.3% and 84.5%, respectively. For veins, the sensitivity and specificity were 39.1% and 92.2%, respectively. Collecting system opening prediction sensitivity was 85.7%, and specificity was 65.2%. Conclusion : Virtual partial nephrectomy imaging is useful for RAPN planning, particularly regarding arteries and the collecting system. It is hoped that techniques for visualizing veins will improve. J. Med. Invest. 69 : 237-243, August, 2022.