telesurgery. Marescaux et al3 reported on the performance of robot-assisted remote telesurgery as long ago as 2001, but its usefulness has not been confirmed yet because robot-assisted telesurgery requires a more complicated system that can handle massive data flows. Therefore, at the present time, we would recommend sending a mentor to the remote hospital for backup to ensure patient safety during performance of the initial cases. Nevertheless, the global average data transfer rate continues to increase and will become much faster according to a global internet protocol traffic forecast.1 Thus, an increase of regions and institutions that can perform effective telementoring is expected, and we believe that the telementoring system reported in the present study has a promising future. Nobuyuki Hinata, M.D., Ph.D. Masato Fujisawa, M.D., Ph.D. Department of Urology Kobe University Graduate School of Medicine Kobe, Japan References 1. Cisco. Cisco visual networking index: global mobile data traffic forecast update, 2013e2018. 2014. 2. Xu S, Perez M, Yang K, et al. Determination of the latency effects on surgical performance and the acceptable latency levels in telesurgery using the dV-Trainer(Ò) simulator. Surg Endosc. 2014;28: 2569-2576. 3. Marescaux J, Leroy J, Gagner M, et al. Transatlantic robot-assisted telesurgery. Nature. 2001;413:379-380.
The Management of Emphysematous Pyelonephritis and Importance of Minimally Invasive Treatment TO THE EDITOR:
Emphysematous pyelonephritis (EPN) is one of the most common clinical form of emphysematous infections of upper urinary tract.1 EPN is an acute, severe, necrotizing infection of the renal parenchyma and perirenal tissue, which causes gas within the renal parenchyma, collecting system, or perinephric tissue.2 It usually affects one kidney and occurs mostly in diabetic patients.1,3 The combination of the presence of gas-producing microorganisms, a high tissue glucose concentration, and impaired tissue perfusion favors the development of the emphysematous infections of the urinary tract.3 There is no consensus on the method of EPN classification. Recently, the classification of Huang and Tseng has been mostly used. According to this classification, classes 1 and 2 are mild forms of the EPN. Gas confined to renal parenchyma is considered as class 1 and gas extending to perinephric space and confined within the Gerota fascia as class 2.3 Conservative treatment modalities such as broadspectrum antibiotic therapy and minimally invasive 988
procedures (such as percutaneous nephrostomy) have been generally performed for the management of both classes 1 and 2. However, invasive procedures (such as open drainage, nephrectomy) should be used for the management of the patients in whom the gas is extending beyond the Gerota fascia (class 3), gas involving both kidneys, or gas in a solitary functioning kidney (class 4).3 In the past, invasive treatment modalities have been used for nearly all the EPN patients. In a study with a large series, 41 patients were treated with antibiotic treatment alone or with a combination of percutaneous drainage (PCD) and antibiotic treatment.4 To our knowledge, this study is the largest series about the treatment strategies of EPN. In this study, the medical management and minimally invasive treatment rate was 75.8%. The high success rate of the minimally invasive approach was significant and might be a reference when choosing the management modality. Generally, PCD is the initial management strategy for EPN as a minimally invasive treatment choice.1-4 On the other hand, it is noteworthy that in this study, 23 of 32 patients (71.8%) were initially treated with ureteral stent placement. We believe that PCD is more effective than ureteral stenting in a patient with EPN for the eradication of infection and drainage of the gas. Ureteral stenting might be insufficient for the eradication of infected areas at the renal parenchyma and perinephric space, and also, the stent might be obstructed by debris. Furthermore, cystitis might be encountered because of the antegrade migration of the infection caused by the stent. Thus, EPN patients should be carefully chosen for ureteral stent placement. The conservative management modalities such as antibiotic treatment and minimally invasive approaches seem to be more popular in recent studies. This approach might be a promising improvement for the prevention of unnecessary organ and tissue loss. The use of routine periodical imaging modalities in diabetes mellitus patients may aid the early diagnosis of EPN. Tahsin Turunc, M.D. Baris Kuzgunbay, M.D. Department of Urology Faculty of Medicine Baskent University Ankara, Turkey
References 1. Kuzgunbay B, Turunc T, Tokmak N, et al. Tailored treatment approach for emphysematous pyelonephritis. Urol Int. 2011;86: 444-447. 2. Shokeir AA, El-Azab M, Mohsen T, et al. Emphysematous pyelonephritis: a 15-year experience with 20 cases. Urology. 1997;49:343-346. 3. Huang JJ, Tseng CC. Emphysematous pyelonephritis: clinicoradiological classification, management, prognosis, and pathogenesis. Arch Intern Med. 2000;160:797-805. 4. Aswathaman K, Gopalakrishnan G, Gnanaraj L, et al. Emphysematous pyelonephritis: outcome of conservative management. Urology. 2008;71:1007-1009.
UROLOGY 84 (4), 2014
The Management of Emphysematous Pyelonephritis and Importance of Minimally Invasive Treatment TO THE EDITOR:
Emphysematous pyelonephritis (EPN) is one of the most common clinical form of emphysematous infections of upper urinary tract.1 EPN is an acute, severe, necrotizing infection of the renal parenchyma and perirenal tissue, which causes gas within the renal parenchyma, collecting system, or perinephric tissue.2 It usually affects one kidney and occurs mostly in diabetic patients.1,3 The combination of the presence of gas-producing microorganisms, a high tissue glucose concentration, and impaired tissue perfusion favors the development of the emphysematous infections of the urinary tract.3 There is no consensus on the method of EPN classification. Recently, the classification of Huang and Tseng has been mostly used. According to this classification, classes 1 and 2 are mild forms of the EPN. Gas confined to renal parenchyma is considered as class 1 and gas extending to perinephric space and confined within the Gerota fascia as class 2.3 Conservative treatment modalities such as broadspectrum antibiotic therapy and minimally invasive 988
procedures (such as percutaneous nephrostomy) have been generally performed for the management of both classes 1 and 2. However, invasive procedures (such as open drainage, nephrectomy) should be used for the management of the patients in whom the gas is extending beyond the Gerota fascia (class 3), gas involving both kidneys, or gas in a solitary functioning kidney (class 4).3 In the past, invasive treatment modalities have been used for nearly all the EPN patients. In a study with a large series, 41 patients were treated with antibiotic treatment alone or with a combination of percutaneous drainage (PCD) and antibiotic treatment.4 To our knowledge, this study is the largest series about the treatment strategies of EPN. In this study, the medical management and minimally invasive treatment rate was 75.8%. The high success rate of the minimally invasive approach was significant and might be a reference when choosing the management modality. Generally, PCD is the initial management strategy for EPN as a minimally invasive treatment choice.1-4 On the other hand, it is noteworthy that in this study, 23 of 32 patients (71.8%) were initially treated with ureteral stent placement. We believe that PCD is more effective than ureteral stenting in a patient with EPN for the eradication of infection and drainage of the gas. Ureteral stenting might be insufficient for the eradication of infected areas at the renal parenchyma and perinephric space, and also, the stent might be obstructed by debris. Furthermore, cystitis might be encountered because of the antegrade migration of the infection caused by the stent. Thus, EPN patients should be carefully chosen for ureteral stent placement. The conservative management modalities such as antibiotic treatment and minimally invasive approaches seem to be more popular in recent studies. This approach might be a promising improvement for the prevention of unnecessary organ and tissue loss. The use of routine periodical imaging modalities in diabetes mellitus patients may aid the early diagnosis of EPN. Tahsin Turunc, M.D. Baris Kuzgunbay, M.D. Department of Urology Faculty of Medicine Baskent University Ankara, Turkey
References 1. Kuzgunbay B, Turunc T, Tokmak N, et al. Tailored treatment approach for emphysematous pyelonephritis. Urol Int. 2011;86: 444-447. 2. Shokeir AA, El-Azab M, Mohsen T, et al. Emphysematous pyelonephritis: a 15-year experience with 20 cases. Urology. 1997;49:343-346. 3. Huang JJ, Tseng CC. Emphysematous pyelonephritis: clinicoradiological classification, management, prognosis, and pathogenesis. Arch Intern Med. 2000;160:797-805. 4. Aswathaman K, Gopalakrishnan G, Gnanaraj L, et al. Emphysematous pyelonephritis: outcome of conservative management. Urology. 2008;71:1007-1009.
UROLOGY 84 (4), 2014
