Axel Häcker

Incidence, Prevention, and Management of Complications Following Percutaneous Nephrolitholapaxy

CONTEXT Incidence, prevention, and management of complications of percutaneous nephrolitholapaxy (PNL) still lack consensus. OBJECTIVE To review the epidemiology of complications and their prevention and management. EVIDENCE ACQUISITION A literature review was performed using the PubMed database between 2001 and May 1, 2011, restricted to human species, adults, and the English language. The Medline search used a strategy including medical subject headings (MeSH) and free-text protocols with the keywords percutaneous, nephrolithotomy, PCNL, PNL, urolithiasis, complications, and Clavien, and the MeSH terms nephrostomy, percutaneous/adverse effects, and intraoperative complications or postoperative complications. EVIDENCE SYNTHESIS Assessing the epidemiology of complications is difficult because definitions of complications and their management still lack consensus. For a reproducible quality assessment, data should be obtained in a standardized manner, allowing for comparison. An approach is the validated Dindo-modified Clavien system, which was originally reported by seven studies. No deviation from the normal postoperative course (Clavien 0) was observed in 76.7% of PNL procedures. Including deviations from the normal postoperative course without the need for pharmacologic treatment or interventions (Clavien 1) would add up to 88.1%. Clavien 2 complications including blood transfusion and parenteral nutrition occurred in 7%; Clavien 3 complications requiring intervention in 4.1.%; Clavien 4, life-threatening complications, in 0.6%; and Clavien 5, mortality, in 0.04%. High-quality data on complication management of rare but potentially debilitating complications are scarce and consist mainly of case reports. CONCLUSIONS Complications after PNL can be kept to a minimum in experienced hands with the development of new techniques and improved technology. A modified procedure-specific Clavien classification should be established that would need to be validated in prospective trials.

Systematic Evaluation of a Recently Introduced 2-μm Continuous-Wave Thulium Laser for Vaporesection of the Prostate

BACKGROUND AND PURPOSE A novel 2-microm continuous wave (CW) thulium laser device for interventional treatment of benign prostatic hyperplasia was recently introduced into clinical practice and is postulated to have several advantages over more established laser devices. A systematic ex-vivo evaluation of the thulium laser was undertaken to compare the results to transurethral resection of the prostate (TURP) and the potassium-titanyl-phosphate (KTP) laser as reference standard methods. MATERIALS AND METHODS The RevoLix CW thulium laser system was evaluated in the well-established model of the isolated blood-perfused porcine kidney to determine its tissue ablation capacity and hemostatic properties at different power settings. Histologic examination of the ablated tissue followed. The results were compared to the reference standards, TURP and 80-W KTP laser. RESULTS At a power setting of 70 W, the CW thulium laser displays a higher tissue ablation rate, reaching 6.56+/-0.69 g after 10 minutes, compared to the 80 W KTP laser (3.99+/-0.48 g; P<0.05). Only 30 seconds were needed to resect tissue with the same surface area using TURP, resulting in 8.28+/-0.38 g of tissue removal. With a bleeding rate of 0.16+/-0.07 g/min, the CW thulium laser offers hemostatic properties equal to those of the KTP laser (0.21+/-0.07 g/min), and a significantly reduced bleeding rate compared to TURP (20.14+/-2.03 g/min; P<0.05). The corresponding depths of the coagulation zones were 264.7+/-41.3 microm for the CW thulium laser, 666.9+/-64.0 microm for the KTP laser (P<0.05), and 287.1+/-27.5 microm for TURP. CONCLUSION In this standardized ex-vivo investigation, the 2-microm CW thulium laser offered a higher tissue ablation capacity and similar hemostatic properties as those of the KTP laser, and in comparison to TURP both tissue ablation and the bleeding rate were significantly reduced.

Extracorporeally induced ablation of renal tissue by high-intensity focused ultrasound

Authors from Germany describe the use of percutaneously applied high‐intensity focused ultrasound for non‐invasive tissue ablation. They found that the lessons they learned from the use of this technology in animals could be transferred to its use in humans, both of which are described. They indicate that refinements in the technology are essential before this treatment can be used outside the departmental stage.

Does Open Stone Surgery Still Play a Role in the Treatment of Urolithiasis? Data of a Primary Urolithiasis Center

OBJECTIVE The introduction and continuous development of percutaneous nephrolithotomy, the achievement of extracorporeal shock-wave lithotripsy, and the advancements in ureterorenoscopy have led to a revolution in the interventional management urolithiasis. The indications for open stone surgery have been narrowed significantly making it a second- or third-line treatment option. We report on patients undergoing open stone surgery for nephrolithiasis in our department during the last 10 years to examine our indications at a primary urolithiasis center and to determine the clinical situations in which open surgery is a reasonable alternative. PATIENTS AND METHODS We reviewed all patients undergoing open stone surgery for upper urinary tract stones from 1997 until 2007 at the Department of Urology, University Hospital Mannheim. A retrospective chart analysis was performed on these patients to identify factors and indications for open stone surgery. Indications for stone surgery, type of surgery performed, stone complexity, anatomical abnormities present, and the residual stone burden were reviewed. RESULTS During a 10-year period 26 open stone operations were performed in our high-volume center. Indications for open stone removal were complex stone mass with complete or partial staghorn stones, concomitant open surgery, nonfunctioning stone-bearing lower poles, the desire to facilitate future stone passages in cystine stone formers, multiple stones in peripheral calyces, and failed minimal invasive procedures. Procedures performed for stone removal included radial nephrotomies, extended pyelolithotomy, lower pole resection, partial nephrectomy, and ileum ureter replacement. Immediate stone-free rate after a single procedure was 69% (18/26 patients). CONCLUSIONS Although today most stone cases can be handled by minimally invasive treatment, open stone surgery maintains a mandatory role in very selected cases. The most common indication in our series though was complex stones with a high stone burden especially in combination with anatomical variations.

120 W Lithium Triborate Laser for Photoselective Vaporization of the Prostate: Comparison with 80 W Potassium-Titanyl-Phosphate Laser in an Ex-Vivo Model

PURPOSE To evaluate the ablative and hemostatic properties of the recently introduced 120 W lithium triborate (LBO) 532 nm laser and compare the results against the conventional 80 W potassium-titanyl-phosphate (KTP) laser. MATERIALS AND METHODS The ex-vivo model of the isolated blood-perfused porcine kidney was used to determine the ablation capacity, hemostatic properties, and coagulation depth of the GreenLight HPS laser system (American Medical System, Minnetonka, MN) that used an output power of 120 W. The results were compared with the KTP laser that used output power levels of 30 W, 50 W, and 80 W. Unperfused kidneys were weighed before and after 10 minutes of laser ablation in an area of 3 x 3 cm; the weight difference marked the amount of removed tissue. Bleeding was determined by the weight difference of a swab before and after it was placed on the bleeding surface for 60 seconds after ablating a surface area of 9 cm(2) on blood-perfused kidneys. RESULTS With a tissue removal of 7.01 +/- 1.83 g after 10 minutes of laser ablation at 120 W, the LBO laser offered a significantly higher ablation capacity compared with 3.99 +/- 0.48 g reached with the conventional KTP laser at 80 W in the same time interval (P < 0.05). The bleeding rate was also significantly increased using the LBO at 120 W compared with the conventional device at 80 W (0.65 +/- 0.26 g/min vs 0.21 +/- 0.07 g/min; P < 0.05). The corresponding depths of the coagulation zones were 835 +/- 73 microm and 667 +/- 64 microm (P < 0.05), respectively. CONCLUSION The 120 W LBO laser offers a significantly higher tissue ablation capacity compared with the conventional 80 W KTP laser. Because the increased efficacy of the device is accompanied by a higher bleeding rate and a slightly deeper coagulation zone, the user has to select the appropriate output power levels carefully for a safe and efficient treatment. Nevertheless, the bleeding rate compared with previous studies of transurethral resection of the prostate is significantly reduced.

70 vs 120 W thulium:yttrium‐aluminium‐garnet 2 µm continuous‐wave laser for the treatment of benign prostatic hyperplasia: a systematic ex‐vivo evaluation

Study Type – Aetiology (case series)
Level of Evidence 4

Technical characterization of a new bipolar and multipolar radiofrequency device for minimally invasive treatment of renal tumours

To investigate the technical characteristics of a newly developed device for bipolar and multipolar radiofrequency ablation (RFA) of kidney tissue with a resistance‐controlled power output.

Extracorporeal application of high-intensity focused ultrasound for prostatic tissue ablation.

Authors from Mannheim describe their experience with high‐intensity ultrasound for locally confined prostatic carcinoma. This was essentially an in vivo efficacy and safety study, as well as a clinical feasibility study. They found a positive answer to all questions asked. It will be interesting to see if further evaluation leads to a potential clinical use for this technology.

Effect of Pulse Energy, Frequency and Length on Holmium:Yttrium-Aluminum-Garnet Laser Fragmentation Efficiency in Non-Floating Artificial Urinary Calculi

BACKGROUND AND PURPOSE Holmium:yttrium-aluminum-garnet (Ho:YAG) laser lithotripsy is the standard lithotrite in ureteroscopy. We investigated the influence of pulse frequency, energy and length on the fragmentation efficiency of Ho:YAG laser lithotripsy in non-floating artificial stones in vitro. MATERIALS AND METHODS Stone fragmentation efficiency of three different Ho:YAG laser devices were evaluated in vitro at different pulse energy (1.0 and 2.0 J) and frequency settings (5 and 10 Hz), resulting in a standardized output power of 10W, respectively. Where possible, pulse length was modified (350 vs 700 microsec). Each setting was performed with a 273 microm and a 365 microm fiber. Lithotripsy was conducted using non-repulsive stones consisting of soft stone (plaster of Paris) and hard stone composition (Fujirock type 4). RESULTS Our results showed an increased stone disintegration efficiency at higher pulse energy (2.0 J/5 Hz vs 1.0 J/10 Hz) independently of two fiber diameters and stone types applied in this study (P < 0.05 in 18 of 20 groups). Similarly, reduction of the pulse length from 700 to 350 microsec resulted in a higher stone disintegration (P < 0.05 in 13 of 16 groups). This effect was most prominent when applied to soft stones. Higher fiber diameter was not constantly associated with an increase in stone disintegration. CONCLUSION We demonstrate that an increase of pulse energy and a reduction of pulse length at a standardized output power of 10W can improve Ho:YAG laser fragmentation efficiency in vitro in nonfloating stones. These results may potentially affect clinical practice of Ho:YAG laser lithotripsy in impacted or large stones, when retropulsion is excluded.

Prospective evaluation of acute endocrine pancreatic injury as collateral damage of shock-wave lithotripsy for upper urinary tract stones

There has been controversy over whether extracorporeal shock wave lithotripsy (ESWL) can cause damage to the endocrine cells of the pancreas, leading to the later development of diabetes mellitus. Authors from Germany prospectively evaluated acute endocrine pancreatic injury as collateral damage caused by the ESWL for treating upper urinary tract stones. In a careful study they showed that there was no effect on serum levels of variables indicating exocrine and endocrine pancreatic tissue damage, suggesting that the idea that ESWL might lead to future diabetes mellitus is unlikely to be correct.