Commentary

The authors gathered more than 1000 urological LESS reports from 21 institutes and analyzed risk factors for complications and conversion. The use of ancillary needlescopic/mini-laparoscopic ports was considered LESS, adding an extra 5 mm or greater port was considered conversion to reduced port laparoscopy, and unplanned installation of more than 1 port were considered as conversion to laparoscopic surgery. This information is useful when one newly starts utilizing urological LESS.

This report is important for several reasons. First, this is the first report analyzing the risk factors of complication and conversion based on the largest series of urological LESS to date. Second, complications and the degree of technical difficulty are graded according to the standardized systems—the Clavien-Dindo system and the European Scoring System for laparoscopic urological surgery. Using these systems allowed indicated risk factors to be more objectively and reliably categorized.

The most interesting point of the study is that robotic surgery is a factor associated with any type of conversion, even though the difficulty of the procedure is equalized in the multivariable analysis. The current robotic system may not be well designed for LESS. A higher percentage of robotic use for partial nephrectomies (PN) showed the highest conversion rate among the same technical difficulty group (60.9%). Unfortunately, the percentage of robotic use in each procedure was not reported. Adrenalectomy showed the second most frequent conversion rate (23.6%), even though the technical difficulty is less than that of partial, radical or donor nephrectomy. This could be due to the anatomical topography of the adrenal gland as indicated by the authors, particularly in tall patients. But unfortunately, the height of the patients was not included in the multivariable analysis. Another possible reason is that the number of adrenalectomies performed by the authors may be limited. Only 55 adrenalectomies were included in 1163 LESS procedures.

LESS is becoming more popular in urological laparoscopy and many newcomers will start LESS in the near future. This report will be a good guideline in selecting patients for LESS.

Tadashi Matsuda, M.D.

Evaluation of 2,590 urological laparoscopic surgeries undertaken by urological surgeons accredited by an endoscopic surgical skill qualification system in urological laparoscopy in Japan. Habuchi T, Terachi T, Mimata H, Kondo Y, Kanayama H, Ichikawa T, Nutahara K, Miki T, Ono Y, Baba S, Naito S, Matsuda T, Department of Urology, Akita University Graduate School of Medicine, Akita, Japan.

Surg Endosc 2012;26:1656–63.

Background: In 2003, the Japanese Urological Association (JUA) and Japanese Society of Endourology (JSE) established a urological laparoscopic skill qualification system, called the Endoscopic Surgical Skill Qualification System in Urological Laparoscopy of JUA and JSE (ESSQSJJ). The main goal of the system is to decrease the prevalence of complications associated with laparoscopic surgery. To validate the qualification system, perioperative outcome and the prevalence of complications in different types of urological laparoscopic surgery performed by accredited surgeons were evaluated.

Methods: One hundred thirty-six surgeons who obtained the qualification in 2004 were prospectively asked to submit intraoperative and postoperative data of their latest 20 cases at the end of 2009, along with the number of laparoscopic urological surgeries performed in each year for a 5-year period (2004–2009). Intraoperative and postoperative complications were graded according to the Satava classification and modified Clavien classification, respectively.

Results: Data of 2,590 urological laparoscopic surgeries of 130 surgeons, including 904 laparoscopic radical nephrectomies, 430 laparoscopic nephroureterectomies, 390 laparoscopic adrenalectomies, 320 laparoscopic radical prostatectomies, and 170 laparoscopic partial nephrectomies, were analyzed. Complications were noted in 97 (3.7%) patients. Major intraoperative complications (grade II or III) occurred in 32 (1.2%) patients, and major postoperative complications (grade III or higher) occurred in 24 (0.9%) patients. The prevalence of conversion to open surgery, allogeneic transfusion, and perioperative mortality was 2.5%, 1.6%, and 0%, respectively. The number of surgeries performed by each qualified surgeon or the role of the surgeon (main operator vs. mentor/instructor) in the surgery did not affect the prevalence of intraoperative complications or postoperative complications. The open conversion rate was significantly higher in surgeons with a low surgical volume.

Conclusions: ESSQSJJ can ensure urological laparoscopic surgeons who can perform various types of urological laparoscopic surgeries with a low prevalence of perioperative complications and reasonable outcomes.

DOI: 10.1007/s00464-011-2088-0

Commentary

Skill assessment of each surgeon is the key to achieving competency of surgical performance; however, there is no universal system to evaluate surgeons' skills. This report from Japan explores the predictive validity of the ESSQSJJ in urological laparoscopy. The ESSQSJJ is unique in that it includes a variety of surgical subspecialties such as urology, gastrointestinal surgery, gynecology, pediatric surgery, and orthopedic surgery, and assesses all surgical performances on unedited video tapes in a double-blind fashion. The authors reported that the complication and conversion rates of surgeries for urologists who qualified 5 years previously, when the ESSQSJJ was instituted, were comparable to the reports from high volume centers, indicating good predictive validity of the system.

Interesting points of this report is that the authors evaluated the influence of the surgical volume and the role in each surgery of the qualified surgeons. They showed that the role of the surgeon, whether a qualified lead surgeon or a trainee with a qualified surgeon present, did not affect the prevalence of complications, conversion to open surgery, bleeding volume more than 500ml, and blood transfusion, though operation time was significantly longer when the qualified surgeon participated as mentor. This means that qualified surgeons have a significant role not only as good surgeons but also as good instructors of young surgeons, and this should be the final goal of assessment of surgical competency. The authors also reported that surgical volume influenced the incidence of open conversion—in particular, laparoscopic partial nephrectomy—and the mean operating time and blood transfusion rate of laparoscopic radical prostatectomy. This would confirm the technical difficulty of these two procedures.

Overall, this report showed the predictive validity of skill assessment on unedited video tapes, even though several limitations of the study are indicated by the authors.

Tadashi Matsuda, M.D.

Commentary

The authors report a survey of urologists on the subject of kidney stone management. In particular, they sought to determine whether urologists' preference of treatment modality is based on urologists' own demographic factors. They found that there was indeed a strong correlation between factors such as practice type (community versus academic), lithotriptor ownership, and time since training when correlated to preferred treatment modality for a variety of clinical scenarios (shock wave lithotripsy [SWL] versus ureteroscopy or percutaneous nephrolithotomy [PCNL]). Given that stone management guidelines are not proscriptive, allowing for patient and surgeon preference in the majority of situations, this is not entirely surprising.

First, let me address the limitations of this study. Only 180 surveys were completed of 600 sent, a return rate of just 30%, representing roughly 2% of all AUA members. The respondents were representative of the AUA in terms of region, but the authors did not report whether there was a bias toward community or academic practice. Given that 29% of respondents reported having done additional endourological training after residency, there is a distinct possibility that urologists with an interest in stone disease management may have been more likely to respond.

The results suggest that urologists who have been in practice longer were more likely to choose SWL. This finding can be explained by improvements in training which have made endoscopic treatment, in particular flexible ureteroscopy, routine practice for many younger urologists. This is supported by the authors' finding that preference for rigid as opposed to flexible ureteroscopy was associated with the choice of SWL, as well as the finding that urologists who had further endourological training chose SWL less often regardless of time since training.

Lithotriptor ownership can be considered a contentious issue, as it raises the possibility of financial incentives affecting clinical decision making. The authors report a strong correlation between lithotriptor ownership and SWL preference, independent of urologist age and lithotriptor availability. This raises the possibility of conflict of interest in stone treatment, which has not been explored in detail in the literature.

Urologists in community practice were more likely to choose SWL, which may be influenced by a variety of other factors such as reimbursement and time pressures. Urologists in academic practice might have other reasons to prefer endoscopic management over SWL. Further research might shed light on the actual decision making process, including the possibility that urologists in academic practice with high-volume stone practices are typically sent cases that have failed SWL in the community. Just as community urologists who own lithotriptors may be biased towards SWL, academic urologists whose practice depends on referrals for flexible ureteroscopy may be biased in the opposite direction.

In summary, the treatment offered to patients in the U.S. appears to be determined by urologists' training, practice setting, and lithotriptor ownership. The urological community as a whole would benefit from greater insight into what modality of treatment is preferred by patients, rather than being guided primarily by our biases.

Francis X. Keeley, M.D.

Long-term endoscopic management of upper tract urothelial carcinoma: 20-year single-centre experience. Cutress ML, Stewart GD, Wells-Cole S, Phipps S, Thomas BG, Tolley DA, The Scottish Lithotriptor Centre, Western General Hospital Edinburgh Urological Cancer Group, University of Edinburgh, Edinburgh, UK.

BJU Int 2012 May 7 [epub ahead of print].

Study Type - Therapy (case series) Level of Evidence 4 What's known on the subject? and What does the study add? Endoscopic management of small, low-grade, non-invasive upper tract urothelial cell carcinoma (UTUC) is a management option for selected groups of patients. However, the long-term survival outcomes of endoscopically-managed UTUC are uncertain because only four institutions have reported outcomes of more than 40 patients beyond 50 months of follow-up. Moreover, there is significant variance in the degree of underlying UTUC pathology verification in some of these reports, which precludes an analysis of disease-specific survival outcomes. The present study represents one of the largest endoscopically managed series of patients with UTUC, with a long-term follow-up. The degree of verification of underlying UTUC pathology is one of the highest, which allows a grade-stratified analysis of different outcomes, including upper-tract recurrence-free survival, intravesical recurrence-free survival, renal unit survival and disease-specific survival. These outcomes provide further evidence suggesting that endoscopic management of highly selected, low-grade UTUC can provide effective oncological control, as well as renal preservation, in experienced centres.

Objective: To report the long-term outcomes of patients with upper tract urothelial cell carcinoma (UTUC) who were treated endoscopically (either via ureteroscopic ablation or percutaneous resection) at a single institution over a 20-year period.

Patients and Methods: Departmental operation records were reviewed to identify patients who underwent endoscopic management of UTUC as their primary treatment. Outcomes were obtained via retrospective analysis of notes, electronic records and registry data. Survival outcomes, including overall survival (OS), UTUC-specific survival (disease-specific survival; DSS), upper-tract recurrence-free survival, intravesical recurrence-free survival, renal unit survival and progression-free survival, were estimated using Kaplan-Meier methods and grade-stratified differences were analyzed using the log-rank test.

Results: Between January 1991 and April 2011, 73 patients underwent endoscopic management of UTUC with a median age at diagnosis of 67.7 years. All patients underwent ureteroscopy and biopsy-confirmation of pathology was obtained in 81% (n = 59) of the patients. In total, 14% (n = 10) of the patients underwent percutaneous resection. Median (range; mean) follow-up was 54 (1–223; 62.8) months. Upper tract recurrence occurred in 68% (n = 50). Eventually, 19% (n = 14) of the patients proceeded to nephroureterectomy. The estimated OS and DSS were 69.7% and 88.9%, respectively, at 5 years, and 40.3% and 77.4%, respectively, at 10 years. The estimated mean and median OS times were 119 months and 107 months, respectively. The estimated mean DSS time was 190 months.

Conclusions: The present study represents one of the largest reported series of endoscopically-managed UTUC, with high pathological verification and long-term follow-up. Upper-tract recurrence is common, which mandates regular ureteroscopic surveillance. However, in selected patients, this approach has a favourable DSS, with a relatively low nephroureterectomy rate, and therefore provides oncological control and renal preservation in patients more likely to die eventually from other causes.

© 2012 The Authors. BJU International © 2012 BJU International.

DOI: 10.1111/j.1464-410X.2012.11169.x

Commentary

The authors report their experience with endoscopic management of 73 patients with upper tract urothelial carcinoma (UTUC). As with any retrospective report of a 20-year experience, this provides a valuable resource for long-term outcomes while making it difficult to draw definite conclusions due to the fact that the methods of management varied and probably evolved over time. There does not appear to be a standard method of management nor of surveillance. Most of the patients (86%) were managed entirely with ureteroscopy and a minority with a combination of percutaneous resection and ureteroscopy. One quarter had topical mitomycin, although in most cases this was given intravesically with a stent in situ and should not be categorized as upper tract treatment. Most importantly, not all patients had regular endoscopic surveillance—some had IVU or CT urography. Thus, the actual recurrence rate may have been underestimated, since imaging is less sensitive than endoscopic surveillance. Nonetheless, this is an impressive experience and a great effort was made by the authors to present all of the data in a logical format.

The relatively large cohort of patients with long-term follow-up allowed for an analysis of the data by grade. The grade was determined in 80% of cases and was G1 in nearly half. The authors report, unsurprisingly, that low grade (G1) correlated with better disease-specific survival (DSS) than G2 or G3. Of interest is the fact that recurrence was high in all grades (68% overall) and was estimated to be 80% at 10 years. This argues for lifelong endoscopic surveillance. A total of 22 patients (30%) failed endoscopic treatment, defined as progression, mortality, or nephroureterectomy.

The data support to a large degree what other pioneering centers have reported—namely, that an endoscopic biopsy to determine grade is the single most important part of management. Grade determines outcome for patients regardless of their treatment. For the G1 group, it was estimated that none required a nephroureterectomy at 5 years and only 20% at 10 years. This argues strongly for nephron-sparing surgery to be extended to low-grade upper tract tumors, just as it has been for small renal masses.

The only aspect of this report that I found difficult to understand was the reporting of imaging follow-up alongside endoscopic follow-up. I do not feel that these are equivalent methods for detecting local recurrence. Outcomes of bladder cancer management do not include imaging of the bladder in place of cystoscopy and nor should outcomes of treatment of upper tract urothelial carcinoma. Nonetheless, this would only affect local recurrence reporting, not progression, overall survival, or cancer-specific survival.

Overall, this series makes a significant contribution to the rather limited literature on the endoscopic management of this relatively rare disease.

Francis X. Keeley, M.D.

Commentary

These two studies both examine immediate outcomes after PCNL. Shahrour and associates retrospectively evaluated results of single tract PCNL in 351 cases completed over a 10-year period. The single tract was chosen based on the location that would permit access to the greatest amount of stone burden, and the technique was supplemented with same-session percutaneous flexible nephroscopy as well as retrograde prone flexible ureteroscopy. Stones inaccessible with rigid instruments were retrieved with flexible instruments and placed in the renal pelvis where they could then be removed with the rigid scope. Patients suspected of harboring residual stones underwent abdominopelvic CT scans on the first postoperative day and then second-look nephroscopy if stone burden remained. The definition of stone-free in this study was no evidence of calculi on endoscopy with antegrade pyelography and postoperative CT. Using such strict criteria, the stone-free rate (SFR) after the initial PCNL, performed by two fellowship-trained and experienced endourologists, was only 51%. This attests dramatically to what most urologists already know: PCNL is a frustratingly difficult undertaking due to a myriad of anatomical, stone, and equipment related factors. After second-look nephroscopy, the SFR improved to 76%. This begs the question: could the SFR have been higher if multiple tracts were used? The answer is undoubtedly yes, but at what cost? The transfusion rate in this series was barely over 1% and only 5.7% of patients suffered Clavien Grades III-IV complications. Unfortunately, the authors did not specify the average size of residual stones. Given the effort expended intraoperatively in both the initial and second look procedures, I suspect most patients in this series had a relatively minor remaining stone burden. Would it have been worth the additional risk of transfusion and potentially serious complications that would likely have attended the use of multiple tracts? That is a question that each urologist needs to ask him- or herself and, in my opinion, determine the answer to preoperatively and in consultation with each patient.

The second study comes from the Clinical Research Office of Endourological Society's (CROES) global survey of PCNL. As the title suggests, Xue and associates examined outcomes of PCNL on an enormous number (>1400) of solitary non-staghorn stones measuring over 2 cm in diameter. This subset of stones was chosen in order ensure accuracy in assessment of stone size. Not surprisingly, the investigators found that larger stone size was associated with lower SFR, higher transfusion requirements, and greater likelihood of Clavien I-III complications. The SFR ranged from 88.3% to 90%, as determined by various modalities dictated by local protocols. There is fair certainty that use of more stringent and uniform criteria, such as those used by Shahrour and associates, would have yielded a significantly lower range of stone-free rates. There are few things more disappointing to the practicing percutaneous nephrolithotomist than the finding of residual stones following surgery for a solitary nephrolith—yet, clearly, certain situations may predispose to such an occurrence. Depending on composition and initial size, the calculus may fragment into numerous tiny pieces. This is particularly true for stones with a high apatite content. Irrigant used for visualization may blow stone fragments into an adjacent calyx that is impossible to examine even with a flexible scope. A solitary stone may present within a calyeal diverticulum or in a branch of the collecting system drained by a stenotic infundibulum. Both of these anatomical abnormalities may add a great deal of complexity to what otherwise may seem a simple situation. Additionally, a calyceal diverticular stone that appears solitary on preoperative imaging may actually be found to consist of numerous small calculi. These may find their way to other calyces as a result of manipulations during surgery. A high degree of suspicion that stone fragments could have migrated to other locations in the kidney, as well as an exhaustive approach to examining all calyces as espoused in the Shahrour paper, will decrease the risk of residual calculi after PCNL for solitary lithiasis.

Robert Marcovich, M.D.

Commentary

Despite being a safe, effective and non-invasive treatment for urolithiasis, shock wave lithotripsy (SWL) is associated with rare (<1%) but serious adverse events such as perirenal hemorrhage. Several studies have attempted to define risk factors for this rare complication. I read with interest the current paper aimed at assessing clinical and lithotripter-related risk factors for clinically significant perirenal hemorrhage after SWL. The authors reviewed the Japanese national database of inpatients using ICD-10 codes of 26,969 patients undergoing 32,476 SWL treatments in 482 hospitals using 38 lithotripters and found an overall incidence of renal hemorrhage to be 0.30%. On multivariate analysis, the authors found that ureteral stones (OR 0.29; P < 0.001), piezoelectric lithotripters (OR 0.13, P = 0.04) and high-volume (≥140 SWL/year) hospitals (OR 0.49, P = 0.01) to be associated with significantly lower risk of perirenal hemorrhage. Contrary to previous studies suggesting smaller focal zones with higher peak-pressures being associated with perirenal hemorrhage, the authors found no significant difference in the incidence of perirenal hemorrhage when comparing focal sizes (≤400mm³ vs. >400mm³) and F2 angles (≤70° vs. >70°). Similarly, age and gender were not significant risk factors. Similar to other studies based on national databases, the current study suffers from lack of clinical data regarding the severity and final outcome of patients being readmitted with perirenal hemorrhage post-SWL.

A recent matched case-control study of 6172 SWL treatments for proximal ureteral and renal stones found male gender, intraoperative hypertension (≥140/90, HR 3.302, 1.066–10.230, p = 0.0384), and anticoagulant/antiplatelet drugs (HR 4.198, 1.103–15.984, p = 0.0355) to be significant predictors of post-SWL clinically significant perirenal hemorrhage.¹ In 2009, the American Urological Association published a White Paper statement summarizing animal studies regarding renal injury post-SWL.² Pretreatment with priming dose followed by a pause of three to four minutes and using slower rates (1 Hz instead of 2 Hz) were associated with less renal injury. However, these results need to be confirmed in clinical trials. Currently, there is a multi-center Canadian RCT comparing success rates and perirenal hemorrhage rates between two focal sizes (narrow vs. wide) of the same lithotripter (Clinicaltrials.gov ID: NCT01226875). The results of this trial will provide some answers regarding the role of the focal size as a risk factor for perirenal hemorrhage.

References

1. Fuller A, Foell K, Mendez-Probst C, et al. Shockwave lithotripsy induced perinephric hematoma: a matched case-control analysis of risk factors. J Urol 2012;187: e622.

2. Lingeman JE, Mcateer JA, Assimos DG, et al. Current perspective on adverse effects in shock wave lithotripsy. American Urological Education Series, White Paper, 2009.

Sero Andonian, M.D.

Abdominal fat distribution on computed tomography predicts ureteric calculus fragmentation by shock wave lithotripsy. Juan HC, Lin HY, Chou YH, Yang YH, Shih PM, Chuang SM, Shen JT, Juan YS, Department of Urology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.

Eur Radiol 2012 Mar. 14 [epub ahead of print].

Objectives: To assess the effects of abdominal fat on shock wave lithotripsy (SWL). We used pre-SWL unenhanced computed tomography (CT) to evaluate the impact of abdominal fat distribution and calculus characteristics on the outcome of SWL.

Methods: One hundred and eighty-five patients with a solitary ureteric calculus treated with SWL were retrospectively reviewed. Each patient underwent unenhanced CT within 1 month before SWL treatment. Treatment outcomes were evaluated 1 month later. Unenhanced CT parameters, including calculus surface area, Hounsfield unit (HU) density, abdominal fat area and skin to calculus distance (SSD) were analysed.

Results: One hundred and twenty-eight of the 185 patients were found to be calculus-free following treatment. HU density, total fat area, visceral fat area and SSD were identified as significant variables on multivariate logistic regression analysis. The receiver-operating characteristic analyses showed that total fat area, para/perirenal fat area and visceral fat area were sensitive predictors of SWL outcomes.

Conclusion: This study revealed that higher quantities of abdominal fat, especially visceral fat, are associated with a lower calculus-free rate following SWL treatment. Unenhanced CT is a convenient technique for diagnosing the presence of a calculus, assessing the intra-abdominal fat distribution and thereby helping to predict the outcome of SWL.

Key Points • Unenhanced CT is now widely used to assess ureteric calculi. • The same CT protocol can provide measurements of abdominal fat distribution. • Ureteric calculi are usually treated by shock wave lithotripsy (SWL). • Greater intra-abdominal fat stores are generally associated with poorer SWL results.

DOI: 10.1007/s00330-012-2413-6

Commentary

Stone fragmentation and subsequent stone-free rates after extracorporeal shockwave lithotripsy are dependent on patient and stone characteristics, lithotripter type, operator (urologist and radiological technologist) and shock wave firing parameters.^1–3 The current study retrospectively evaluated effects of abdominal fat distribution on unenhanced CT for 185 patients with a solitary ureteral stone being treated with the Siemens Lithostar at a rate of 2 Hz with a maximum of 3500 shocks. On multivariate analysis, the authors found that stone surface area (>0.3 cm²), stone density (HU > 733), skin-to-stone distance ([SSD] >11.2 cm), abdominal circumference (>88.2 cm), total fat area (>268 cm²), para/perirenal fat area (>49 cm²), and visceral fat area (>95 cm²) were significantly associated with lower stone-free rates. Interestingly, subcutaneous fat area (>222 cm²) did not reach significance. I think that SSD as a variable is dependent on the lithotripter's focal length rather than the type of tissues it is composed of (fat, muscle or kidney) since in an in vitro study stone fragmentation was similar whether shockwaves passed through fatty or non-fatty (muscle and kidney) tissues.⁴ For example, in the current study, the SSD cut-off of 11.2 cm is related to the focal length of 12 cm of the Siemens Lithostar lithotripter. Therefore, the cut-off values used here would be different for other lithotripters with longer focal lengths. The authors are to be commended for their meticulous work. However, it is labor-intensive to trace total and visceral fat areas. On the other hand, stone density (HU) and SSD are easily measured and used in clinical practice to determine which patients are good candidates for the local shockwave lithotripter. Therefore, the clinical value of measuring intra-abdominal fat areas remains to be determined.

References

1. Elkoushy MA, Morehouse DD, Anidjar M, et al. Impact of radiological technologists on the outcome of shock wave lithotripsy. Urology 2012;79:777–80.

2. Rassweiler JJ, Knoll T, Köhrmann KU, et al. Shock wave technology and application: an update. Eur Urol 2011;59:784–96.

3. Elkoushy MA, Hassan JA, Morehouse DD, et al. Factors determining stone-free rate in shock wave lithotripsy using standard focus of Storz Modulith SLX-F2 lithotripter. Urology 2011;78:759–63.

4. Hammad FT, Al Najjar A. The effect of fat, muscle, and kidney on stone fragmentation by shockwave lithotripsy: an in vitro study. J Endourol 2010;24:289–92.

Sero Andonian, M.D.

Commentary

This article by Ahyai et al is an important clarification around the issue of efficiency with endoscopic procedures for the surgical treatment of BPH. For procedures where measurable tissue is obtained there are a number of benefits: 1) histologic evidence of prostatic carcinoma is found in 5–10% of cases and in some of these patients this information will change their management; 2) a measure of completeness of removal of the transition zone is obtained as this weight of tissue correlates directly with transition zone volume measured by ultrasound (Fong et al, unpublished data); 3) an assessment of the efficiency and speed of the procedure is provided and this is useful in tracking the mastery of techniques such as HoLEP, the learning curve of which is easily quantifiable in these terms; and 4) it allows direct comparison of different procedures in which the vast majority of the tissue has been retrieved.

Procedures in which the tissue is coagulated predominantly or vaporized do not lend themselves to this type of comparison or scrutiny and surrogate measures must be found, such as the change in prostatic ultrasound volume 6 and 12 months postoperatively and/or the fall in PSA which has often been disappointingly small. While a fall in PSA level of 70–80% is normal with HoLEP, laser vaporization techniques rarely exceeded 50% and procedures such as TUNA have no measurable effect.

A study from our institution was the first to show that HoLEP was more efficient than TURP when grams per minute were compared—when corrected for tissue weight the two procedures were similar (HoLEP having been slower when raw times were considered) but when comparing the energy time, i.e., resection and enucleation alone, excluding tissue retrieval, enucleation was faster.¹

Why does this matter? Well, apart from improved surgical throughput, which comes with reduced OR times, there is little value in increasing the speed of surgery itself. A much more important aspect is the fact that removing more tissue from a given prostate by a technique such as enucleation leads to improved relief of obstruction¹, less likelihood of reoperation for BPH and thus better durability in the long term.²

References

1. Tan AH, Gilling PJ, Kennett KM, et al. Randomized trial comparing holmium laser enucleation of prostate with transurethral resection of prostate for treatment of bladder outlet obstruction secondary to benign prostatic hyperplasia in large glands (40 to 200 grams). J Urol 2003;170:1270–4.

2. Gilling PJ, Wilson LC, King CJ, et al Long-term results of a randomized trial comparing holmium laser enucleation of the prostate and transurethral resection of the prostate: results at 7 years. BJU Int 2012;109:408–11.

Peter Gilling, M.D.

Laser treatment of benign prostatic obstruction: basics and physical differences. Bach T, Muschter R, Sroka R, Gravas S, Skolarikos A, Herrmann TR, Bayer T, Knoll T, Abbou CC, Janetschek G, Bachmann A, Rassweiler JJ, Department of Urology, Asklepios Klinik Barmbek, Hamburg, Germany.

Eur Urol 2012;61:317–25.

Context: Laser treatment of benign prostatic obstruction (BPO) has become more prevalent in recent years. Although multiple surgical approaches exist, there is confusion about laser-tissue interaction, especially in terms of physical aspects and with respect to the optimal treatment modality.

Objective: To compare available laser systems with respect to physical fundamentals and to discuss the similarities and differences among introduced laser devices.

Evidence Acquisition: The paper is based on the second expert meeting on the laser treatment of BPO organised by the European Association of Urology Section of Uro-Technology. A systematic literature search was also carried out to cover the topic of laser treatment of BPO extensively.

Evidence Synthesis: The principles of generation of laser radiation, laser fibre construction, the types of energy emission, and laser-tissue interaction are discussed in detail for the laser systems used in the treatment of BPO. The most relevant laser systems are compared and their physical properties discussed in depth.

Conclusions: Laser treatment of BPO is gaining widespread acceptance. Detailed knowledge of the physical principles allows the surgeon to discriminate between available laser systems and their possible pitfalls to guarantee high safety levels for the patient.

Copyright © 2011 European Association of Urology. Published by Elsevier B.V. All rights reserved.

DOI: 10.1016/j.eururo.2011.10.009

Commentary

This article by Bach et al provides an excellent resource for urologists wishing to understand the terminology and physics behind the large array of lasers currently available to treat BPH. This paper was produced by the EAU Section of Urotechnology.

When first introduced in 1990, there was only one wavelength to consider (1064 nm, Nd:YAG) although a number of ways of utilizing the energy itself soon arose, i.e., interstitial and free-beam coagulation and vaporization. Others soon became available and there now are four laser groups to choose from: Ho:YAG, Thu:YAG, KTP/LBO and the various diodes. The absorbing chromophore of each, e.g., water, haemoglobin or protein, plays a large part in determining the best way to use a given wavelength and also determines safety issues, particularly at lower power, but as the power increases tissue is predominantly vaporized by all of these devices when used as a free beam.

There are also four basic techniques for treating BPH with either transurethral or open approaches: coagulation (Nd:YAG and RF), vaporization/ablation (all lasers and RF), resection/incision (Ho:YAG, Thu:YAG mainly and RF) and enucleation (open, Ho:YAG and, recently, other wavelengths). Putting it all together, it becomes clear that the characteristics of the lasers are only one part of the puzzle. The way a given laser/wavelength is currently utilized is dictated partly by its physics, partly by its history and the techniques for which it was originally used, and partly by the innovation of both urologists and manufacturers constantly looking to optimize their market share.

One thing is for certain—there is now a laser wavelength for every possible surgical technique. The technique a urologist chooses will depend on the influences and training he is subject to, his caseload and the size of gland he wishes to treat, the equipment he has available to him and the interest he has in the subject. There is certainly no “one size fits all.”

Peter Gilling, M.D.

Commentary

By means of [¹³C₂] oxalate the authors were able to clearly demonstrate the enteric hyperabsorption of oxalate as the reason for high urinary oxalate in their patients with hyperoxaluria. The association with urolithiasis is emphasized and supported by the findings in this article. It seems essential to counteract oxalate absorption in patients with high levels of oxalate in urine. As expected, the high urinary oxalate levels were seen in patients with bowel resections and stone formation.

High supersaturation with CaOx follows urinary hyperoxaluria and it is likely that urinary pH is also low in these patients, although no differences were recorded in urinary citrate. Therapeutic tools in addition to alkali, high fluid intake and enzymatic approaches are suggested. I also think that addition of calcium supplements should be given in a dose titrated manner from their effect on urinary oxalate. This might be particularly important during periods of peak supersaturation with CaOx. It has indeed been highly interesting to learn when the peak excretion of [¹³C₂] oxalate occurred in relation to the intake of oxalate-containing food.

Hans-Göran Tiselius, M.D.

The diurnal variation in urine acidification differs between normal individuals and uric acid stone formers. Cameron M, Maalouf NM, Poindexter J, Adams-Huet B, Sakhaee K, Moe OW, Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX.

Kidney Int 2012;81:1123–30.

Many biological functions follow circadian rhythms driven by internal and external cues that synchronize and coordinate organ physiology to diurnal changes in the environment and behavior. Urinary acid-base parameters follow diurnal patterns and it is thought these changes are due to periodic surges in gastric acid secretion. Abnormal urine pH is a risk factor for specific types of nephrolithiasis and uric acid stones result from excessively low urine pH. Here we placed 9 healthy volunteers and 10 uric acid stone formers on fixed metabolic diets to study the diurnal pattern of urinary acidification. All showed clear diurnal trends in urinary acidification, but none of the patterns were affected by inhibitors of the gastric proton pump. Uric acid stone formers had similar patterns of change throughout the day but their urine pH was always lower compared to healthy volunteers. Uric acid stone formers excreted more acid (normalized to acid ingestion), with the excess excreted primarily as titratable acid rather than ammonium. Urine base excretion was also lower in uric acid stone formers (normalized to base ingestion), along with lower plasma bicarbonate concentrations during part of the day. Thus, increased net acid presentation to the kidney and the preferential use of buffers, other than ammonium, result in much higher concentrations of undissociated uric acid throughout the day and consequently an increased risk of uric acid stones.

DOI: 10.1038/ki.2011.480.

Commentary

This article is highly interesting in view of the analysis of circadian rhythm of urine acidification. Urine was analyzed in 1- or 2-hour collection periods during the day with low pH levels in both healthy volunteers and in patients with uric acid stone formation. The low pH in the evening as well as during the night is indeed highly interesting.

The aim of this study was to specifically examine the situation in patients with uric acid stone disease, but a detailed understanding of urine acidification seems to be of fundamental importance also for patients with calcium oxalate stone disease. The apparently important relationship between precipitates of calcium phosphate and calcium oxalate needs to be considered in view of how urine pH varies during the day.¹

The patients in this study were on a metabolic well-defined diet and they also seemed to have a rather generous supply of water. But under normal clinical conditions, what would the pH profile be in normal subjects and in calcium oxalate stone formers? Can the findings in this report be translated into a better urine analysis approach?

Reference

1. Tiselius HG. A hypothesis of calcium stone formation: an interpretation of stone research during the past decades. Urol Res 2011;39:231–43.

Hans-Göran Tiselius, M.D.

Variations between two 24-hour urine collections in patients presenting to a tertiary stone clinic. Nayan M, Elkoushy MA, Andonian S, Division of Urology, Department of Surgery, McGill University Health Centre, McGill University, Montreal, QC.

Can Urol Assoc J 2012;6:30–3.

Introduction: The current Canadian Urological Association (CUA) guideline recommends two 24-hour urine collections in the metabolic evaluation for patients with urolithiasis. The aim of the present study was to compare two consecutive 24-hour urine col- lections in patients with a history of urolithiasis presenting to a tertiary stone clinic.

Methods: We retrospectively reviewed 188 patients who had two 24-hour collections upon presentation between January 2010 and December 2010. Samples were collected on consecutive days and examined for the following 11 urinary parameters: volume, creatinine, sodium, calcium, uric acid, citrate, oxalate, potassium, phosphorous, magnesium and urea nitrogen. For each parameter, the absolute value of the difference between the two samples rather than the direct difference was compared with zero. Similarly, the percent difference between samples was calculated for each parameter.

Results: The means of the absolute differences between the two samples were significantly different for all 11 urinary parameters (p < 0.0001). The percent differences for all urinary parameters ranged from 20.5% to 34.2%. Furthermore, 17.1% to 47.6% of patients had a change from a value within normal limits to an abnormal value, or vice-versa. Significance was maintained when patients with incomplete or over-collections were excluded.

Conclusions: Significant variations among the two 24-hour urine collections were observed in all of the 11 urinary parameters analyzed. This variation may change clinical decision-making in up to 47.6% of patients if only a single 24-hour urine collection is obtained. The present study supports the CUA guideline of performing two 24-hour urine collections.

DOI: 10.5489/cuaj.11131

Commentary

That variation in composition of 24-hour urine samples occurs and should be expected is well recognized. The recommendation to collect two samples therefore is included not only in CUA guidelines, but also in EAU-guidelines.¹ It also has been shown that with an increased number of collections the number of urine abnormalities increases.² From a clinical point of view, one urine sample is better than no urine sample. Many patients are reluctant to collect urine and they probably do it with variable accuracy. A 20% variation in creatinine excretion certainly very well reflects this problem. It has been my own routine to collect one sample and if no abnormality can be discovered in a patient with pronounced risk of stone formation to repeat the collection. Urine composition varies from one day to another as well as from one part of the year to another.

The major question in modern recurrence prevention treatment is not whether we should analyze composition in one or several 24-hour urine samples, but rather if we get sufficient information by only looking at one or several averages during the day. In my mind more efficient recurrence prevention can be expected if we are able to identify specific risk periods during the day and design our therapy accordingly. Such a regimen is likely to be more efficient and also to result in much better patient compliance.

It would thus have been stimulating if the authors had questioned the way in which we have looked at risk factors in urine from stone formers during the past several decades. Modern stone research needs a more dynamic approach in this regard and it seems to be of high priority to identify correctly in the individual patient when peaks of supersaturation with CaOx and CaP occurs during the 24-hour period. Only in that way will it be possible for us to further move recurrence prevention from where we are today.

References

1. Tiselius HG, Alken P, Buck C, Gallucchi M, Knoll, T, Sarica K, Türk. Guidelines on Urolithiasis. European Association of Urology, 2009. www.uroweb.org/fileadmin/tx_eauguidelines/2009/Full/Urolithiasis.pdf

2. Hess B, Hasler-Strub U, Ackermann D, Jaeger P. Metabolic evaluation of patients with recurrent idiopathic calcium nephrolithiasis. Nephrol Dial Transplant 1997;12:1362–8.

Hans-Göran Tiselius, M.D.

Commentary

NOTES appears to be the next frontier in minimally invasive urology. The seminal work by Sotelo, Kaouk and Alcaraz was instrumental in the concept of “pure” NOTES nephrectomy becoming reality.^1–3 However, the transvaginal route is automatically sex selective. This proof of concept study is the first that shows the feasibility of a NOTES nephrectomy with kidney extraction after morcellation using the transvesical approach. This exciting study has shown that transvesical NOTES nephrectomy is possible even with the present clunky instrumentation. To make it a clinical reality is a big leap of faith and will require significant advances in the technology currently described by the authors. However, the study remains a step in the right direction.

References

1. Sotelo R, de Andrade R, Fernández G, et al. NOTES hybrid transvaginal radical nephrectomy for tumor: stepwise progression toward a first successful clinical case. Eur Urol 2010;57:138–44.

2. Kaouk JH, White WM, Goel RK, et al. NOTES transvaginal nephrectomy: first human experience. Urology 2009;54:5–8.

3. Alcaraz A, Peri L, Molina A, et al. Feasibility of transvaginal NOTES assisted laparoscopic nephrectomy. Eur Urol 2010;57:233–7.

Abhay Rane, M.S.

Inpatient safety trends in laparoscopic and open nephrectomy for renal tumours. Stroup SP, Palazzi KL, Chang DC, Ward NT, Parsons JK, UC San Diego Medical Center, Division of Urology VA San Diego Medical Center Moores UCSD Cancer Center, Division of Urologic Oncology, San Diego, CA.

BJU Int 2012 Apr. 3 [epub ahead of print].

Study Type - Cohort study • Level of Evidence 2b • What's known on the subject? and What does the study add? Laparoscopic radical nephrectomy for renal cancer provides equivalent long-term cancer control with shorter hospital stays, less postoperative pain, and faster resumption of normal activities, but it has diffused slowly into clinical practice, perhaps as a result of perceptions about safety. Patient safety outcomes for laparoscopic and open radical nephrectomy using validated measures remain incompletely characterized. This is the first study to investigate peri-operative outcomes of radical nephrectomy using validated patient safety measures. We found a 32% decreased probability of adverse patient safety events occurring in laparoscopic compared with open radical nephrectomy. The safety benefits of laparoscopy were attained only after 10% of cases were completed laparoscopically - a proportion some have proposed as the ‘tipping point’ for the adoption of surgical innovations. This observation could have implications for patient safety in the setting of diffusion of new surgical techniques.

Objective: To compare perioperative adverse patient safety events occurring in laparoscopic radical nephrectomy (LRN) with those occurring in open radical nephrectomy (ORN).

Methods: We used the US Nationwide Inpatient Sample to identify patients undergoing kidney surgery for renal tumours from 1998 to 2008. We used patient safety indicators (PSIs), which are validated measures of preventable adverse outcomes, and multivariate regression to analyse associations of surgery type with patient safety.

Results: Open radical nephrectomy accounted for 235,098 (89%) cases while 28,609 (11%) cases were LRN. Compared with ORN, LRN patients were more likely to be male (P = 0.048), have lower Charlson comorbidity scores (P < 0.001), and to undergo surgery at urban (P < 0.001) and teaching (P < 0.001) hospitals. PSIs occurred in 18,714 (8%) of ORN and 1434 (5%) of LRN cases (P < 0.001). On multivariate analysis, LRN was associated with a 32% decreased probability of any PSI (adjusted odds ratio 0.68, 95% confidence interval: 0.6 to 0.77, P < 0.001). Stratification by year showed that this difference was initially manifested in 2003, when the proportion of LRN cases first exceeded 10%.

Conclusions: We found that LRN was associated with substantially superior perioperative patient safety outcomes compared with ORN, but only after the national prevalence of LRN exceeded 10%. Further study is needed to explain these patterns and promote the safe diffusion of novel surgical therapies into broad practice.

© 2012 The Authors. BJU International © 2012 BJU International.

DOI: 10.1111/j.1464-410X.2012.11071.x.

Commentary

LRN may be now considered as the reference standard for radical nephrectomy since it provides equivalent long-term cancer control with shorter hospital stays, less postoperative pain, and faster resumption of normal activities. This paper confirms that the use of LRN results in substantially enhanced perioperative patient safety as compared to ORN; this lower likelihood emerged after the national prevalence of LRN exceeded the “tipping point” of 10%. Lack of patient-specific oncological data, including tumor size or tumor stage, is a potential limitation of the present study as are variations in coding practices over the 10-year study period, which may have influenced the analyses. Since LRN is no longer the novel procedure that is was once considered to be, this study also confirms the sobering thought that the patient's ZIP code still may determine which type of approach is used for extirpative renal surgery, and ultimately the level of inpatient safety.

Abhay Rane, M.S.

Commentary

This recent study of the Nationwide Inpatient Sample examined the differences in complication outcomes for patients undergoing RARP versus open RP. This database includes inpatient discharge data collected by federal-state partnerships encompassing more than 1000 community hospitals in 44 states regardless of payor status. This examination of patients from 2008–2009 showed that RARP is the most common procedure with 61.7% of all cases.

Regarding the complication status, there was a clear superiority demonstrated in favor of RARP. There were also fewer blood transfusions, fewer extended hospital stays and fewer mortalities. These differences were still statistically significant where propensity score-matched outcomes were adjusted for multiple characteristics. As can be seen in the next paper, this superiority is likely to grow rather than abate.

David Lee, M.D.

Temporal national trends of minimally invasive and retropubic radical prostatectomy outcomes from 2003 to 2007: results from the 100% Medicare sample. Kowalczyk KJ, Levy JM, Caplan CF, Lipsitz SR, Yu HY, Gu X, Hu JC, Department of Urology, Georgetown University Hospital, Washington, DC.

Eur Urol 2012;61:803–9.

Background: Although the use of minimally invasive radical prostatectomy (MIRP) has increased, there are few comprehensive population-based studies assessing temporal trends and outcomes relative to retropubic radical prostatectomy (RRP).

Objective: Assess temporal trends in the utilization and outcomes of MIRP and RRP among US Medicare beneficiaries from 2003 to 2007.

Design, Setting, and Participants: A population-based retrospective study of 19 594 MIRP and 58 638 RRP procedures was performed from 2003 to 2007 from the 100% Medicare sample, composed of almost all US men ≥65 yr of age.

Intervention: MIRP and RRP.

Measurements: We measured 30-d outcomes (cardiac, respiratory, vascular, genitourinary, miscellaneous medical, miscellaneous surgical, wound complications, blood transfusions, and death), cystography utilization within 6 wk of surgery, and late complications (anastomotic stricture, ureteral complications, rectourethral fistulae, lymphocele, and corrective incontinence surgery).

Results and Limitations: From 2003 to 2007, MIRP increased from 4.9% to 44.5% of radical prostatectomies while RRP decreased from 89.4% to 52.9%. MIRP versus RRP subjects were younger (p < 0.001) and had fewer comorbidities (p < 0.001). Decreased MIRP genitourinary complications (6.2-4.1%; p = 0.002), miscellaneous surgical complications (4.7-3.7%; p = 0.030), transfusions (3.5-2.2%; p = 0.005), and postoperative cystography utilization (40.3-34.1%; p < 0.001) were observed over time. Conversely, overall RRP perioperative complications increased (27.4-32.0%; p < 0.001), including an increase in perioperative mortality (0.5-0.8%, p = 0.009). Late RRP complications increased, with the exception of fewer anastomotic strictures (10.2-8.8%; p = 0.002). In adjusted analyses, RRP versus MIRP was associated with increased 30-d mortality (odds ratio [OR]: 2.67; 95% confidence interval [CI], 1.55-4.59; p < 0.001) and more perioperative (OR: 1.60; 95% CI, 1.45-1.76; p < 0.001) and late complications (OR: 2.52; 95% CI, 2.20-2.89; p < 0.001). Limitations include the inability to distinguish MIRP with versus without robotic assistance and also the lack of pathologic information.

Conclusions: From 2003 to 2007, there were fewer MIRP transfusions, genitourinary complications, and miscellaneous surgical complications, whereas most RRP perioperative and late complications increased. RRP versus MIRP was associated with more postoperative mortality and complications.

DOI: 10.1016/j.eururo.2011.12.020

Commentary

In a similar vein as the article by Trinh et al, this fascinating study examined the 100% sample of Medicare beneficiaries comparing the outcomes of those who underwent a minimally invasive prostatectomy versus open radical prostatectomy. There was a clear shift over time in an increasing number of MIRP cases being performed, reaching a high of 44.5% by 2007. Certainly, this number will have increased up to the current day as shown in the previous study.

Not surprisingly, the overall number of MIRP complications did not change; however, some specific factors did indeed improve such as GU complications, surgical complications, use of blood transfusions and cystography and rectourethral fistulas. What was very surprising is that the number of RRP complications rose over the same time period, from 27.4% to 32%. Broken down by specific complications, even perioperative mortality was seen to rise.

When compared head-to-head, there is very little competitive comparison. MIRP was, simply put, a safer operation than RRP. The power of such a study as this is the nationwide view of patients and their perioperative course. Specific centers of excellence are, of course, going to have data that is better than the national averages. But these excellent single-center experiences are not what every patient should expect but the high bar that all surgeons should strive to reach. Therefore, an over-arching view such as this with its attendant limitations should still provide to the reader what the delta is between the outstanding centers and where the rubber meets the road for our typical urologic patient in the U.S. Apparently, the MIRP is continuing to provide an increasingly safer course for patients while the same may not be true for RRP. When the naysayers of robotic surgery say there is no data demonstrating improved outcomes for that approach, they should be cognizant of studies such as this and wonder if RRP is the stalwart that it was thought to be.

David Lee, M.D.

Commentary

The main finding of this pilot study is that specific “lesion targeted ablation” of individual biopsy-proven cancer lesions with a certain margin of ablative tissues (instead of “hemi-ablation” that ablates one entire side of the prostate) could reduce treatment side-effects in men with localized prostate cancer. The primary objective of this study was well described in terms of feasibility, patient acceptability, and a low side-effect profile of lesion-targeted focal HIFU. However, this study only provided limited oncological outcomes, including MRI images at 6 and 12 months, and targeted biopsies at 6 months from the treated areas only (with a median core number of 6). Importantly, actual histological outcomes of postoperative biopsy at 6 months were slightly worse than those reported for hemi-ablation. Thus, the debate concerning “lesion targeted focal therapy” has just started.

The reason for the slightly worse histological outcomes of this study need to be clarified in a follow-up study. The strategy of utilizing additional ablative tissues for certain margins from the known biopsy-proven cancer lesion (instead of hemi-ablation) provides important implications on the goal of focal therapy regarding both oncological and functional outcomes. Determination of whether to preserve or sacrifice a neurovascular bundle adjacent or close to the tumor is challenging. Clearly, even the use of the most modern imaging can overestimate or underestimate the actual cancer lesion. To date, there is little evidence concerning the role of imaging after focal ablative therapy, but this study also provides some data of the potential roles and limitations of MRI in follow-ups after lesion-targeted ablation. There is a big challenge in the precise preoperative prediction of cancer volume as well as the pathologic contour of the cancer lesion. In this study, the authors worked toward their decision-making using MRI visibility, outcomes of template prostate-mapping biopsies or both, for the selection of patients and determination of the targeting ablative area. The ablative lesions were determined as having at least a 3–5 mm margin around them based on 2–4 HIFU pulses using the Sonablate HIFU machine. Such a treatment strategy is totally dependent on which modalities would be applied in the diagnostic and therapeutic processes. Nevertheless, this study provides important baseline data of the challenging strategy toward lesion-targeted ablative focal therapy instead of hemi-ablation.

Osamu Ukimura, M.D., Ph.D.