Commentary

Laparoscopic partial nephrectomy (LPN) is an ideal procedure of choice for treatment of small renal cancers, leaving good renal function postoperatively with minimum morbidity. The problems are technical difficulties and renal functional damage due to warm ischemic time (WIT). To overcome these challenges, renal hypothermia is one of the alternatives for non-ischemic partial nephrectomy, such as that proposed by Gill et al¹, which requires highly skilled hands.

This paper demonstrates a simple method to achieve suboptimal renal cooling, and precise evaluation of split renal function using DMSA renal scintigraphy. Among a variety of methods for renal hypothermia, including simple ice slush insertion to the retroperitoneal space, ice-cold saline perfusion of the renal pelvis, arterial cold saline perfusion, or ice gel insertion², ice-cold saline shower application around the kidney is the easiest method when performing retroperitoneal LPN. Although its use is limited to the retroperitoneal approach, more than half of LPNs in Japan are performed in this manner.

Split renal function, rather than simple eGFR, should be monitored to evaluate the effect of partial nephrectomy on kidney function. Renal scintigraphy, Tc99m MAG3 is the best method of evaluation.

One of the questions to be answered in this paper is the necessity of 10 minutes of cooling time before starting the resection of the tumor after clamping of the renal artery. How about 5 minutes to cool the kidney to the suboptimal level? In particular, would the tumor location be adequate to cool only the involved half of the kidney? Because the single indicator of postoperative decrease of the ipsilateral renal function by the multivariate analysis was WIT, efforts should be focused on decreasing WIT.

In an era when chronic kidney disease is known as one of the most important factors of cardiovascular disease, simple methods of renal hypothermia are useful to encourage LPN.

References

1. Gill IS, Eisenberg MS, Aron M, et al. “Zero ischemia” partial nephrectomy: novel laparoscopic and robotic technique. Eur Urol 2011;59:128–134.

2. Schoeppler GM, Klippstein E, Hell J, et al. Prolonged cold ischemia time for laparoscopic partial nephrectomy with a new cooling material: Freka-Gelice–a comparison of four cooling methods. J Endourol 2010;24:1151–1154.

Tadashi Matsuda, M.D.

Mental practice enhances surgical technical skills: a randomized controlled study. Arora S, Aggarwal R, Sirimanna P, Moran A, Grantcharov T, Kneebone R, Sevdalis N, Darzi A, Department of Surgery and Cancer, Imperial College London, St. Mary's Hospital, London, UK.

Ann Surg 2011;253:265–270.

Objective: To assess the effects of mental practice on surgical performance.

Background: Increasing concerns for patient safety have highlighted a need for alternative training strategies outside the operating room. Mental practice (MP), “the cognitive rehearsal of a task before performance,” has been successful in sport and music to enhance skill. This study investigates whether MP enhances performance in laparoscopic surgery.

Methods: After baseline skills testing, 20 novice surgeons underwent training on an evidence-based virtual reality curriculum. After randomization using the closed envelope technique, all participants performed 5 Virtual Reality (VR) laparoscopic cholecystectomies (LC). Mental practice participants performed 30 minutes of MP before each LC; control participants viewed an online lecture. Technical performance was assessed using video Objective Structured Assessment of Technical Skills-based global ratings scale (scored from 7 to 35). Mental imagery was assessed using a previously validated Mental Imagery Questionnaire.

Results: Eighteen participants completed the study. There were no intergroup differences in baseline technical ability. Learning curves were demonstrated for both MP and control groups. Mental practice was superior to control (global ratings) for the first LC (median 20 vs 15, P = 0.005), second LC (20.5 vs 13.5, P = 0.001), third LC (24 vs 15.5, P < 0.001), fourth LC (25.5 vs 15.5, P < 0.001) and the fifth LC (27.5 vs 19.5, P = 0.00). The imagery for the MP group was also significantly superior to the control group across all sessions (P < 0.05). Improved imagery significantly correlated with better quality of performance (ρ 0.51–0.62, Ps < 0.05).

Conclusions: This is the first randomized controlled study to show that MP enhances the quality of performance based on VR laparoscopic cholecystectomy. This may be a time- and cost-effective strategy to augment traditional training in the OR thus potentially improving patient care.

DOI: 10.1016/j.jamcollsurg.2010.09.025

Commentary

What is the best method for improving the surgical practice of trainees, particularly for laparoscopic or robotic surgeries? Practice in the operation theater is not allowed now due concern for patient safety. Yes, simulators are the major form of surgical practice, but it requires considerable cost for institutions and time of young surgeons.

This paper is important in that it demonstrates the usefulness of mental practice (MP) by using a validated manipulation check. MP is defined as the cognitive rehearsal of a task in the absence of overt physical movement. It is accepted that mental imagery activates similar neural processes to those used in actual performance of a given skill, for example in music or sports. The authors used a validated MP script, which demonstrates detailed maneuvers of real surgery prepared to practice mentally. What kinds of procedures should be done in real surgery, using what kinds of instruments by both hands? What kinds of findings or difficulties would be encountered during the real practices, and how are they overcome? MP should include these details of the surgery to improve the trainees' practices. In this paper, the usefulness of MP is clearly shown using scientific manner. The work we are required to do is to prepare detailed MP scripts for all urologic laparoscopic or robotic surgeries to facilitate urologic laparoscopic trainees. Simulators for each surgery such as laparoscopic nephrectomy or adrenalectomy might be unnecessary if an MP for each surgery is well prepared.

Tadashi Matsuda, M.D.

Commentary

The authors retrospectively reviewed the hospital records of 1,798 consecutive outpatient ureteroscopic procedures for stones performed over a 10-year period at a tertiary care hospital to determine risk factors for unplanned admission on the day of surgery. They had a low rate of unplanned admission of 3.9%. The most common cause for admission was pain. They analyzed a large number of potential risk factors and found by multivariate analysis that unexpected admissions were related to a history of previous admission related to stones, history of psychiatric illness and bilateral procedure. Patients with distal ureteral stones were less likely to require admission.

There are a number of limitations to this study which the authors mention in the discussion, including its retrospective nature, the fact that all procedures were done at a tertiary care facility, and that they did not examine readmission rates, just unplanned admissions on the day of surgery. Other limitations of the study as reported include the lack of data on stone size, operating time, ASA grade or other comorbidity measurements, or their indications for planned admissions. The authors have previously reported higher readmission rates for patients undergoing prolonged intrarenal ureteroscopic procedures without stenting.¹ One wonders if those same patients are at higher risk for unplanned admission. It would be helpful to know if patients with large volume renal calculi undergoing ureteroscopy were treated as planned admissions rather than outpatients, in light of their previous report.

The authors deserve credit for choosing a large sample size with a case-matched control group. Their finding that a history of a psychiatric condition was an independent risk factor is interesting and may be explained by more difficult pain management in this group of patients. Their low rate of unexpected admissions demonstrates the low perioperative morbidity of ureteroscopy in a high-volume center.

Reference

1. Hollenbeck B, Schuster T, Seifman B, et al. Identifying patients who are suitable for stentless ureteroscopy following treatment of urolithiasis. J Urol 2003;170:103–106.

Francis X. Keeley, M.D.

Cost-effectiveness and efficiency of shockwave lithotripsy vs flexible ureteroscopic holmium:yttrium-aluminium-garnet laser lithotripsy in the treatment of lower pole renal calculi. Koo V, Young M, Thompson T, Duggan B, Stone Treatment Centre, Craigavon Area Hospital, Portadown, and Department of Urology, Belfast City Hospital, Belfast, Northern Ireland, UK.

BJU Int 2011 Mar. 31. [epub ahead of print]

Study Type - Therapy (cost effectiveness)

Level of Evidence 2b

What's known on the subject? and What does the study add? Stone management economics is a complex issue. FURS and SWL are recognised treatment option for lower pole kidney stones. There are paucity of data comparing cost implication and effectiveness of both treatment options. Both treatment modalities are equally efficacious. FURS incurred greater cost burden compared to SWL in the UK setting. In the present economic circumstance, clinicians should also consider cost-impact, patient's preference and specific clinical indication when counselling patients for treatment.

Objective:

• To compare the cost-effectiveness and outcome efficiency of extracorporeal shockwave lithotripsy (SWL) vs intracorporeal flexible ureteroscopic laser lithotripsy (FURS) for lower pole renal calculi ≤20 mm.

Patients and Methods:

• Patients who had treatment for their radio-opaque lower pole renal calculi were categorized into SWL and FURS group.

Results:

• The FURS (n = 37) and SWL (n = 51) group were comparable with respect to sex, age, stone size and the presence of ureteric stent.

Conclusion:

• SWL was efficacious and cost-effective for the treatment of lower pole renal calculi ≤20 mm.

© 2011 The Authors; BJU International © 2011 BJU International

DOI: 10.1111/j.1464–410X.2011.10172.x.

Commentary

The authors report a cost analysis of shockwave lithotripsy (SWL) and flexible ureterorenoscopy (URS) for the treatment of single lower pole renal calculi less than 20 mm. This retrospective study did not report data on patient preference or quality of life, but previous studies have shown better patient experience with SWL than URS.¹ Their clinical outcomes are in keeping with the published literature and show no difference between the two groups. Their cost analysis, however, deserves thorough consideration. They report that the “actual cost” of SWL is considerably less than URS. One must be careful, of course, when discussing costs and charges.

It is helpful to know how services in the British National Health Service (NHS) are costed and charged. All staff in NHS hospitals, including physicians, are salaried and all procedures are billed according to national tariffs (charges). SWL carries a tariff of £592 ($963 U.S.). By contrast, flexible URS carries a tariff of £1910 ($3108 U.S.). Standard practice in the NHS is for URS to be carried out by a consultant. SWL, by contrast, is most commonly performed by radiographers with medical input limited to analgesic management and advice regarding treatment plans, although there are considerable variations in staffing.

The authors report an actual cost of £2602 for URS, compared to £426 for SWL. They conclude that “SWL was efficacious and cost-effective for the treatment of lower pole renal calculi < 20 mm.”

There are several aspects of the study that should be questioned. Firstly, the authors do not discuss why their URS patients required an average of over two days of hospitalization (see above review of Tan et al.), although they hint that one patient with a complication may have skewed the data. If that is the case, then they should have reported a median length of stay and considered the one case as an outlier. Our patients have a median length of stay of less than one day. Secondly, they do not state their criteria for selection of cases for SWL or flexible URS. Although the two groups were well-matched in terms of stone size, this retrospective study may not reveal significant differences between the groups, i.e. history of UTIs or failed SWL, two common indications for URS. In other words, patients in the URS group may have been more complex.

Flexible ureteroscopy for lower pole stones typically involves one-use-only equipment as well as fragile ureteroscopes and a laser, all of which are not cheap. By contrast, SWL uses fewer resources and one might expect that the cost of the procedure would simply take into account the cost of purchase and maintenance of the machine, staff costs, drugs, and room charges.

While these findings are interesting, the authors rightly emphasize the fact that costs vary considerably from country to country. One suspects that SWL costs and charges vary more than that for most other procedures.

Reference

1. Pearle MS, Lingeman JE, Leveillee R, et al. Prospective, randomized trial comparing shock wave lithotripsy and ureteroscopy for lower pole caliceal calculi 1 cm or less. J Urol 2005;173:2005–2009.

Francis X. Keeley, M.D.

Commentary

These two recent articles address the issue of percutaneous nephrolithotomy (PNL) in anomalous kidneys. In a multicenter effort, Binbay and colleagues assessed the effect of simple malrotation (i.e., malrotation without other anomalies such as ectopy or fusion) on PNL outcomes using matched pair analysis. Forty-four patients with simple malrotation were culled from a group of over 5000 PNLs and matched to 44 patients without malrotation. There were no differences in any of the outcome parameters assessed, including number and location of accesses, stone-free rate, operative time, fluoroscopy time, and Clavien complication rate. Twice the number of patients with malrotation required blood transfusion (13.6% vs. 6.8%), but the difference was not statistically significant. There were also twice as many Clavien 3a complications and pneumothoraces in the malrotation group. While the authors concluded that blood loss and complications were similar in patients with and without malrotation, I suspect that a difference would have been found either with a larger sample size or with 2-to-1 or 3-to-1 matching. Nevertheless, the authors provide an excellent discussion of the possible reasons for the increased blood loss, namely that malrotation can lead to fluoroscopically mistaking an anterior calyx for a posterior one, increased intraparenchymal distance of percutaneous tracts, and the need to apply more torque with rigid instruments. The former pitfall would likely have been minimized had all patients in the study been preoperatively evaluated with CT, and/or had ultrasound been used to obtain access. This study illustrates the importance of cross-sectional imaging in planning the approach to percutaneous access, especially in patients with suspected renal anomalies.

The second study assessed outcomes of PNL in patients with anatomic or functional solitary kidneys. The authors calculated estimated glomerular filtration rate (eGFR) using the modification of diet in renal disease (MDRD) formula in 44 patients pre- and postoperatively. A quarter of the patients required multiple 30 F tracts. Just over 25% of patients had residual fragments requiring adjunctive shock wave lithotripsy (SWL) with or without ureteroscopy (URS). One patient required angioembolization for severe hemorrhage. Over the course of a minimum of 6 months of follow-up, the average eGFR of the overall cohort improved or remained stable, a finding consistent with previous studies. Three patients (7%) experienced deterioration of function, including two diabetic patients and the patient who required embolization. While not explicitly stated, it does not appear that those patients who had ancillary SWL or URS experienced decreased eGFR, a comforting fact, given that urologists might be hesitant to expose a solitary kidney to the additional trauma of SWL, even in cases in which the residual fragments after PNL are clinically significant.

Robert Marcovich, M.D.

Commentary

Kidney stone surgical management is a field where the transition from more invasive to less invasive has hit a bump in the road. Shock wave lithotripsy at many centers has become a rarely performed procedure, replaced by expanded utilization of ureteroscopy with laser lithotripsy and percutaneous nephrolithotomy (procedures with predictably-high success rates and an acceptable risk profile). Without a more effective SWL machine that can achieve results approaching the HM3, SWL is at risk of becoming of historic interest.

For those centers that have replaced suboptimal lithotripters with the Storz SLX-F2 machine, the SWL results are blatantly obvious within weeks of treating patients: this powerful machine breaks stones but with a higher risk of subcapsular and perinephric hematomas. Within 6 months of installation at our high-volume lithotripsy center, the dramatically improved SWL results resulted in a marked reduction in our ureteroscopy case load and a reduction in the numbers of percutaneous nephrolithotomy salvage cases post-failed SWL.

The RCT described in this paper recruited both elective and emergent renal and ureteral stone patients and compared the SWL results and complications of treatment with either the gold-standard HM3 lithotripter versus the SLX-F2. To no surprise, the results demonstrate that the HM3 remains the king of the stone hill but the results for the SLX-F2 are clearly a step above what many of us achieved with prior alternatives to the HM3.

An area of concern in this study is the use of high energy levels during SLX-F2 treatments of both renal and ureteral calculi. The authors begin with a 500 shock wave pre-treatment at level 7 with eventual treatment at the maximum energy level of 9, with later reduction if stone fragmentation is evident. This high energy level is not in keeping with the recommendations Storz has given to users during North American installations. My own discussions with colleagues in North America who have not heeded the advice of the manufacturer to slowly ramp up on the energy level to a maximum of 4–5 during the first 500–1000 shocks reveals the rapid ramp-up users developing a significant experience managing bleeding complications post-SWL. However, despite following the manufacturer's recommendations, ours and other large-volume SWL centers can attest to cases of unpredicted and massive retroperitoneal bleeds, even to the point of requiring angiography and selective embolization.

Although this machine breaks stone, caution is warranted: start low and go slow.

Ryan F. Paterson, M.D.

Commentary

This paper reported on a contemporary experience of 918 patients undergoing surgical treatment of symptomatic BPH in a single center in Korea. Unusually, all patients underwent transrectal prostate volumetry preoperatively, performed by second-year residents (22 residents over the study period), leading to potential inter-observer error. Also gathered were PSA measurements, DRE, uroflow studies and ultrasound-measured residual urine volumes. All were treated by the same surgeon with either TURP or open prostatectomy. Resected weights and times were defined and recorded, allowing accurate calculation of resection efficiency.

Mean age was greater for the open prostatectomy cohort (72.1 years, n = 75) compared to the TURP cohort (67.9 years, n = 843), unsurprisingly. The performance ratio between open prostatectomy and TURP, respectively, changed from 64% vs. 36% in 1999 to 3% vs. 97% in 2010 in favor of TURP. Moreover, the total prostate volume significantly increased in the study period from 40 to 55 cc (p = 0.031) in the TURP cohort, and from 74.1 to 116.7 cc (p = 0.016) in the open prostatectomy cohort. The low initial transurethral resection volume of 2.3 cc reflected inexperience in performing TURP at the start of the study, and resection weight steadily increased, while resection times steadily fell over the study period, improving resection efficiency overall from 0.03 to 0.46 cc/min. Curiously, flow rates and IPSS scores did not change, although the authors did not state when exactly these parameters were measured, and for how long each patient was followed with these outcome measures. Stricture rate increased in the mid-study period to 49% (alarmingly high), falling thereafter to 9.2%, which was attributed to use of warmed irrigant rather than a 2Fr drop in resectoscope size.

It is possible that during the study period, prostates increased in volume while patients remained on medical therapy alone (which may indicate low utility of cytoreductive therapy with a 5-alpha reductase inhibitor) or alternatively, it may reflect patient selection bias towards larger glands for resection due to increased surgeon confidence and progression up the TURP learning curve. However, prostate volumes also increased significantly in the open prostatectomy cohort, where the surgeon was already proficient in the technique at the start of the study and selection bias would most likely have a smaller effect, if any.

The initial learning curve for the surgeons in this report to tackle larger glands was approximately 2 years (looking at Figure 1), and after this period, open prostatectomy was performed in less than 10%. However, looking at resection efficiency in Figure 3, surgical resection learning continued throughout the 10-year period, showing year-on-year improvement, which almost doubled in the last 2 years.

Today's residents perform woefully small numbers of endoscopic prostate resections during their training, as this reviewer noted in a previous Survey Section commentary.¹ This highlights the imperative for investing in routine and regular use of near “real-life” transurethral resection simulators in urology residency training in concert with proficiency testing, if future patients are to avoid paying a higher price in both morbidity and reoperation, as prostates become larger during the medical therapy paradigm era (particularly monotherapy), leading to more difficult resection scenarios, worse long-term outcomes from incomplete resection, and higher costs in an increasingly aging population.

Reference

1. Patel A. Commentary. J Endourol 2010;24:1213.

Anup Patel, M.D.

Commentary

The authors have reported their results of a huge series of stone analyses carried out in Germany between 1977 and 2006. Although, as the authors state, epidemiological conclusions cannot be drawn, the number of analyses nevertheless is extremely informative.

There are some notes of specific interest. The increased male-to-female ratio during the period does not concur with some other recent observations. The high frequency of uric acid stones is higher than that observed, for instance, in Scandinavia, and probably the occurrence of uric acid is even higher if the medical dissolution is taken into account. The reduced occurrence of infection stones is in line with the development elsewhere and explains why infection staghorn stones nowadays are a rarity. It is of note that brushite is found in only a very small fraction of the stones and although there is a tendency to an increased occurrence during the past years, patients with brushite stones still constitute only a minor and very special group.

A lot of interesting data can be obtained from consistent analyses of stone composition. It is my advice that stone analysis everywhere become part of the clinical evaluation of every stone forming patient. In addition to epidemiological changes that constantly seem to occur, one major reason for analyzing stones is to find those patients who have formed infection, and whether they developed uric acid, cystine and brushite stones, because all these patients—irrespective of their stone history—should be considered for recurrence prevention.

Hans-Göran Tiselius, M.D., Ph.D.

Can Hounsfield unit values of the cortex and papillae determined by computed tomography demonstrate the possibility of kidney stone formation? Baran I, Voyvoda N, Tokgöz O, Tokgöz H, Zonguldak Karaelmas University School of Medicine, Department of Radiology, Turkey.

Eur J Radiol 2011 Apr. 13 [epub ahead of print]

Purpose: This study is aimed at measuring HU values of the renal cortex and papillae in patients with neprolithiasis and demonstrating renal changes associated with nephrolithiasis.

Materials and Methods: Measurements were performed with regard to HU values of the cortex and papillae of 82 patients with unilateral nephrolithiasis and 81 patients in the control group at the level of the upper pole, middle region and lower pole of both kidneys.

Results: When the HU values obtained from the upper pole, middle region and lower pole of the kidney with calculi and unaffected kidney in patients with nephrolithiasis were compared with those for the control group, the difference among the groups were found to be significant (p < 0.001). A comparison of the cortex and papillae densities of the affected and unaffected kidneys in patients with unilateral nephrolithiasis were compared with regard to the upper pole and middle region, no statistically significant difference was observed with regard to both the cortex and papillae densities of the upper pole, middle region. However, in those patients with calculi in the lower pole, the region with calculi has a higher papillae density as compared to the unaffected region.

Conclusion: Both kidneys in patients with calculi have a comparatively high renal cortex and papillae densities. In the future, this information may be useful in predicting which patients may develop nephrolithiasis.

Copyright © 2011. Published by Elsevier Ireland Ltd.

DOI: 10.1016/j.ejrad.2011.03.054

Commentary

One major problem in urolithology is determining for whom and when pharmacological recurrence preventive measures should be instituted. Several mechanisms are considered important for formation of calcium oxalate (CaOx) stones and no single abnormality can be incriminated for the pathology. Inasmuch as CaOx is the dominating stone crystal phase, it is highly interesting to seriously consider the role of papillary subepithelial apatite accumulations (Randall's plaques) in this type of stone formation. The presence of subepithelial calcium phosphate deposits, unfortunately, cannot be easily identified on standard x-ray films.

Recent observations^1,2 as well as the findings reported in this article suggest the possible clinical value of measuring the Hounsfield density of cortical and papillary areas on CT images.

Since early observations have shown that Randalls's plaques are more common in patients with calcium stone disease than in normal subjects, it seems attractive to combine such radiological findings and urinary risk factors as predictors of the further course of the disease. If such examinations can be developed into a powerful tool it might be useful for appropriately selecting those patients who are most likely to benefit from medical recurrence prevention. It is indeed important to start life-long recurrence preventive regimens only when there is clinical evidence for its usefulness because CaOx stone disease has a highly variable course. So far we do not have a reliable method by means of which the further course of the disease can be predicted in an accurate way. It will thus be highly interesting to learn what a more extensive experience with HU densities on CT images can add to the care of our CaOx stone forming patients.

References

1. Bhuskute NH, Yap WW, Wah TM. A retrospective evaluation of Randalls' plaque theory of nephrolithiasis and CT attenuation values. Eur J Radiol 2009;72:470–472.

2. Eisner BH, Iqbal A, Namasivayam S, et al. Differences in computed tomography of the renal papillae of stone formers and non-stone formers: a pilot study. J Endourol 2008;22:2207–2210.

Hans-Göran Tiselius, M.D., Ph.D.

Commentary

Ureteral stents may cause significant discomfort, probably related to ureteric smooth muscle spasm and trigonal irritation. Alpha-adrenoceptor antagonists reduce smooth muscle activity; possible mechanisms of benefit in patients with stent related symptoms could be ureteric and local trigonal smooth muscle relaxation, as well as reducing ureteric motility. This interesting study looked at the evidence that α-adrenoceptor antagonists can reduce stent-related pain and storage symptoms as assessed by the Ureteric Stent Symptoms Questionnaire (USSQ). After an exhaustive literature search, five studies were identified which included 461 patients receiving either tamsulosin or alfuzosin. Treatment ranged from one to six weeks after stent placement, although all USSQ assessments in the study were undertaken at one week. One confounding factor was that different types of stents were used: three studies used polyurethane stents, one used silicone and the fifth study did not comment on the type of stent used. Stone sizes were similar throughout all studies.

On meta-analysis, all five studies showed a reduction in USSQ – urinary symptom and body pain scores. There was a mean reduction of 8.4 (95% CI, 5.6-11.1) in urinary symptom score and 7.2 (95% CI, 2.5-11.8) in body pain score.

This meta-analysis provides evidence that treatment with α-blockers delivers an improvement in pain and storage urinary symptoms after placement of a ureteric stent. Urologists who need to place a ureteric stent should consider prescribing an α-blocker with the aim of improving stent tolerance. However, only a high-quality trial randomizing patient with stents to α-blocker or placebo will provide high level objective evidence to support this postulate.

Abhay Rane, M.S., FRCS

The impact of proximal stone burden on the management of encrusted and retained ureteral stents. Weedin JW, Coburn M, Link RE, Scott Department of Urology, Baylor College of Medicine, Houston, TX.

J Urol 2011;185:542–547.

Purpose: Managing the encrusted and retained ureteral stent is a potentially complex challenge. To improve surgical planning, we hypothesized that proximal stone burden is the most important factor associated with complicated removal, and that computerized tomography more accurately estimates stone burden than plain film x-ray of the kidneys, ureters and bladder.

Materials and Methods: Records were reviewed of patients undergoing surgical removal of an encrusted and retained ureteral stent or nephrostomy at Ben Taub General Hospital from 2007 to 2009. Preoperative imaging consisted of a plain x-ray of the kidneys, ureters and bladder and/or computerized tomography of the abdomen/pelvis. Each encrusted tube was assessed using the FECal (forgotten, encrusted, calcified) grading system and associated stone burden was calculated. Univariate and multivariate analyses were performed to determine factors associated with the need for multiple surgeries.

Results: A total of 55 encrusted and retained ureteral stents and 1 nephrostomy were removed from 52 patients. Mean tube duration was 24.9 months. Most tubes were removed endoscopically (94.2%). Of the patients 21.2% required multiple surgical procedures to remove each tube. Computerized tomography graded stone burden more accurately than plain x-ray of the kidneys, ureters and bladder (94.9% vs 64.4%, p = 0.01). Plain x-ray of the kidneys, ureters and bladder underestimated proximal stone burden in 44.4% of patients who underwent multiple surgeries. When dividing stone burden into 3 categories (0 to 100, 101 to 400 and greater than 401 mm(2)) only proximal stone burden correlated with multiple surgeries and surgical complications (p = 0.01 for both). On multivariate analysis only proximal stone burden was associated with multiple surgeries to remove each tube (OR 12.1, 95% CI 1.5-95.9, p = 0.02 for 101 to 400 mm(2) and OR 18.1, 95% CI 1.7-192.8, p = 0.02 for greater than 401 mm(2)).

Conclusions: In patients with encrusted and retained ureteral stents accurate determination of the proximal stone burden, preferably by computerized tomography, is important for surgical counseling and planning.

Copyright © 2011 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

DOI: 10.1016/j.juro.2010.09.085

Commentary

Encrusted and retained ureteral stents represent the most challenging complication associated with ureteral stents. After ureteral stent placement, encrustation/stone formation can occur at varying rates; the authors of this review postulate that proximal stone burden should guide surgical management. Patients underwent CT, which helped determine this parameter. The stone burden was considered mild if less than 100 mm², moderate if 101 to 400 mm² or severe if greater than 400 mm². Encrustation was considered proximal if superior to the pelvic brim and distal if inferior to the pelvic brim. Each tube was assigned a grade intraoperatively, and by KUB and CT according to the FECal scale. Tube stone burden ranged from 30 to 3,302 mm². Twenty-six males and 26 females underwent surgical removal of 55 encrusted and retained ureteral stents and 1 nephrostomy. Eighty-nine percent had been stented in the past for stone disease. Although mean stent duration was more than 2 years, 94% of patients could still be treated endoscopically. Surgical removal of each tube required a mean 1.2 surgeries and 21.2% of patients required multiple surgeries. Removal was primarily accomplished endoscopically, including cystolithotripsy (69.2%), ureteroscopy with laser lithotripsy (57.7%), PCNL (17.3%) and ESWL (5.8%).

CT appeared to predict the location and grade of tube encrustation accurately to stage the amount of proximal stent encrustation, a critical prognostic variable for the need for multiple procedures and the risk of surgical complications. However, the duration of time for which the stent was indwelling did not correlate with the need for multiple surgical procedures.

A number of workers have postulated that urinary proteomics or urinary metabolic evaluations might identify those at risk for encrustation and direct adjuvant medical therapy to prevent this outcome.¹

I agree that the key to prevention of this challenging complication is better education. Patients need to be counseled aggressively regarding the potential seriousness of the problem if their stents encrust. Hopefully, fewer will then default.

Reference

1. Monga M. The dwell time of indwelling ureteral stents–the clock is ticking but when should we set the alarm? J Urol 2011;185:387.

Abhay Rane, M.S., FRCS

Commentary

Cost has been an ever present issue in the application and spread of robotic surgery. Because of the widespread and very rapid adoption of robotics into the field of prostate cancer surgery, increasing attention has been applied to the topic of new technologies and their associated costs. A recent editorial in the New England Journal of Medicine crystallized many of the arguments.¹ Barbash and Giled pointed out that while a wide range of surgeries were previously performed laparoscopically, application of robotics to these indications may add little but added cost to society's price tag of health care—not only increases in direct costs but also the possibility that the attraction of robotics, valid or not, may increase case volumes, thus also steepening the already awesome financial burden that currently exists.

A case in point is robot-assisted radical prostatectomy. While they are many clinicians and outcomes researchers that sit on either side of the fence, certainly patients are leaning toward the allure of robotics. Although as Barbash and Giled point out that evidence from large scale, multicenter trials are necessary, the feasibility of randomized prospective trials concerning robotic versus open radical prostatectomy is about as likely as the proverbial snowball's survival in a very warm location. However, two recent studies bring forth a little more light on the continuing controversy.

Bolenz and coworkers carefully studied their experience of robotic prostatectomy examining for direct cost and clinicopathologic data in order to identify predictors of direct cost. Findings included that OR time, pelvic drain placement, complications, blood transfusion, and length of stay increased direct costs on univariate analysis. However, preoperative factors could not predict increased costs.

Although this was a single approach study—in other words, the examination was only of robotics—application of this type of study to the open approach would likely yield similar results. As such, proponents of robotics usually find that complication rates are lower in their hands than the open counterpart. This could certainly be a driver of improved cost comparison where in many studies robotics comes out on the short end of the stick in analyses that don't look at this factor.

Along the same lines, Lee and colleagues examined the costs at their institution regarding robotic cystectomy. However, here they compared the robotic procedure outcomes to the open counterpart and came away with some interesting conclusions.

In their comparison, 103 open cystectomy patients were compared to 83 robot cystectomy patients. Lymph node yield was higher in the robotic group, while the operative time was comparable. Length of hospital stay favored robot cystectomy (5.5 vs 8.0 days, p < 0.001) and complication rates were comparable. However, the financial cost of the complications was significantly lower for robot cystectomy group versus the open group.

This study points out very nicely that the overall cost related to the decreased severity of the complications underwent by the robotic group balances out the cost differential. This is powerful data, suggesting that studies need to look beyond the surface of charges related to the in-operating room costs to the overall course of the patient related to complications, and then even further to the very likely overall societal cost benefit of early return to work and productivity that robotic surgery provides.

Reference

1. Barbash GI, Glied SA. New technology and health care costs–the case of robot-assisted surgery. N Engl J Med 2010;363:701–704.

David I. Lee, M.D.

Commentary

This prospective trial of HIFU hemi-ablation of 20 men with low-risk (n = 5) to intermediate risk (n = 15) prostate cancer provides promising support for a future trial of focal therapy using HIFU. The main endpoint of this trial was the safety and side effects of focal therapy by HIFU hemi-ablation during a postoperative 12-month follow-up. It is noteworthy that 89% of men achieved satisfactory urinary continence, erection, and cancer control during the 12 months, while maintaining the rectal wall integrity and enjoying a health-related QOL compared with the baseline.

Additional interesting data were provided in both imaging of the 1.5-Tesla phased array multi-parametric MRI and postoperative 6-month follow-up biopsy. Successful HIFU-treated areas likely had decreased in size on MRI. The 2 men who had preoperative Gleason 6 cancers and positive readings on the postoperative 6-month MRI showed positive follow-up biopsy on the treated side, which revealed 1 mm of Gleason 6 cancer; one had repeated focal HIFU and the other underwent active surveillance. The management of the treatment failure in these 2 cases of small volume low-grade cancer seems reasonable. Although such patients may be the best candidates for active surveillance in principle, this study showed the potential role of multi-parametric MR as a follow-up imaging modality to identify treatment failure as well as image-guided targeting biopsy.

Appropriate selection of candidates for focal therapy is a key to achieving success for targeted therapy. This study was designed to use both imaging of the 1.5-Tesla phased array multi-parametric MRI and template prostate mapping biopsy at trial entry. Since this study had the challenge of including intermediate risk cancer in 75% of the enrolled men, the short-term outcome of cancer control by hemi-HIFU seems encouraging. Further discussion of the appropriateness in using the combination of MR and template prostate mapping biopsy for inclusion criteria as well as involving an intermediate risk group, is expected in the next report from this institution.

Clearly, although further long-term study with larger numbers of patients in a multi-institutional study is necessary to comment on the appropriateness of cancer control using the therapy, this well-designed prospective study contributes to our knowledge.

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