Endourology and Stones Factors Affecting Outcomes of Percutaneous Nephrolithotomy in Horseshoe Kidneys Abdulkadir Tepeler, Priyanka D. Sehgal, Tolga Akman, Ali Unsal, Ekrem Ozyuvali, Abdullah Armagan, and Stephen Y. Nakada OBJECTIVE METHODS
RESULTS
CONCLUSION
To analyze the patient- and procedure-related factors affecting the outcomes of percutaneous nephrolithotomy (PNL) in horseshoe kidneys (HSKs). A retrospective analysis was done of patients with stones in HSKs treated with PNL in 3 referral centers between 1998 and 2013. Demographics, along with perioperative characteristics, were evaluated in detail as to whether or not they had an effect on the success and complication rates. A total of 54 HSKs with calculi in 53 patients were treated with PNL. Mean stone size was 28.4 19.6 mm (range, 10-120 mm). Fifty-three patients were treated through a single tract, and 1 patient required additional access. Access was directed to the upper calyx (n ¼ 27), middle calyx (n ¼ 17), and lower calyx (n ¼ 10) through the intercostal (n ¼ 23) and subcostal (n ¼ 31) areas. Flexible nephroscopy was used in 18.5% of the procedures. Postoperative complications were observed in 9 (16.7%) of the procedures. Success rate was 66.7% after a single session of PNL and increased to 90.7% with additional treatments. Although patient demographics, preoperative imaging, and other operative measures did not have significant effect on the complication rate, stone complexity and multiplicity, in combination with flexible nephroscopy, were found to significantly affect the success rate (P ¼ .026, P ¼ .043, and P ¼ .021, respectively). However, in multivariate analysis stone multiplicity was the only factor that affected success rate (P ¼ .004). Stone parameters play an important role in achieving stone-free status in HSKs. Use of flexible nephroscopy positively affects the success rate by allowing reaching the peripherally located calices. UROLOGY 84: 1290e1294, 2014. 2014 Elsevier Inc.
T
he common renal fusion abnormality, horseshoe kidney (HSK), originates from the abnormal fusion of metanephric blastema during the embryologic period.1 Normal anatomic positioning of the kidneys is arrested by the inferior mesenteric artery due to fusion in the lower poles, resulting in malrotation, anterior displacement, and ectopy of the kidneys. The incidence of this issue has been reported to range from 1 in 400 to 1 in 666.1,2 Kidney stones are found in approximately 21%-60% of HSK cases, making them one of the most common complications.1 Features that complicate the treatment of urolithiasis in HSKs include an anteriorly displaced renal pelvis, poor renal drainage, variability in vascular structure, malrotation, and ectopic location. Although shockwave lithotripsy (SWL) and ureteroscopic laser lithotripsy (URS) are generally
Financial Disclosure: The authors declare that they have no relevant financial interests. From the Department of Urology, University of Wisconsin School of Medicine and Public Health, Madison, WI; the Department of Urology, Faculty of Medicine, Bezmialem Vakif University, Istanbul Turkey; and the Department of Urology, Kecioren Teaching and Research Hospital, Ankara, Turkey Address correspondence to: Abdulkadir Tepeler, M.D., Department of Urology 3rd floor, University of Wisconsin School of Medicine and Public Health, 1685 Highland Avenue, Madison, WI 53705. E-mail: [email protected] Submitted: June 24, 2014, accepted (with revisions): August 7, 2014
1290
ª 2014 Elsevier Inc. All Rights Reserved
recommended for small calculi, percutaneous nephrolithotomy (PNL) is the most commonly used treatment option for large and/or complex renal calculi or in cases where other treatment modalities have failed in HSK. Despite the increased success of PNL, attributable to advances in technology and refinements in operation technique, it still has a significant complication rate. Although factors affecting the success and complication rates of PNL in anatomically normal kidneys are well researched, studies exploring variables associated with outcomes of PNL in HSKs are limited. A recent study evaluating parameters related to success of PNL found that stone parameters were significant.3 To achieve better PNL results in this specific group of patients, therefore, further studies are warranted. In this study, we aimed to systematically analyze the patient- and procedure-related factors affecting the outcomes of PNL in HSKs.
METHODS After obtaining institutional review board approval, a retrospective analysis was done of patients with stones in HSKs treated with PNL in 3 referral centers between 1998 and 2013. Same surgical teams in each center performed the procedures. The following patient demographics were collected: age, gender, http://dx.doi.org/10.1016/j.urology.2014.08.008 0090-4295/14
stone-related parameters, prior therapies, preoperative imaging methods, operative details, and success and complication rates. These demographics, along with perioperative characteristics, were evaluated in detail as to whether or not they had an effect on the success and complication rates. All patients were evaluated with basic laboratory and radiologic methods. Blood count, urinalysis, creatinine, blood urea nitrogen, and coagulation profile were studied. Patients with positive urine culture were treated, as appropriate. All patients underwent a detailed radiologic assessment including intravenous urography (IVU) and/or computed tomography (CT). Stone size was measured based on the imaging method used. Stone complexity (simple, partial staghorn, complete staghorn, or complex stones) and stone multiplicity (single or multiple) were evaluated.
Operative Technique All procedures were done in prone-positioned patients under general anesthesia, with the guidance of fluoroscopy. After gaining access under fluoroscopy, the tract was dilated up to 30 Fr and an Amplatz sheath (Cook Surgical, Bloomington, IN) was inserted into the collecting system. Stone disintegration was performed using ultrasonic, pneumatic lithotripter or laser, through a 24 Fr rigid and/or 15 Fr flexible nephroscope. Additional access was created in any requirement. After endoscopic and fluoroscopic assessment of stone-free status, nephrostomy tubes were left in place. The following intraoperative variables were recorded for analysis: access site (intercostal or subcostal), access location (upper, middle, or lower pole calyx), and nephroscope used (rigid or rigid and flexible). Patients were reevaluated with laboratory tests and plain radiography of kidneys, ureters, and bladder postoperatively. Complications were graded using the Clavien Classification System.4 Nephrostomy tubes were removed on postoperative day 1 or 2. Unless there was an unresolved issue, patients were discharged after removal of the nephrostomy tubes. Stone-free status or the presence of asymptomatic fragments
RESULTS
CONCLUSION
To analyze the patient- and procedure-related factors affecting the outcomes of percutaneous nephrolithotomy (PNL) in horseshoe kidneys (HSKs). A retrospective analysis was done of patients with stones in HSKs treated with PNL in 3 referral centers between 1998 and 2013. Demographics, along with perioperative characteristics, were evaluated in detail as to whether or not they had an effect on the success and complication rates. A total of 54 HSKs with calculi in 53 patients were treated with PNL. Mean stone size was 28.4 19.6 mm (range, 10-120 mm). Fifty-three patients were treated through a single tract, and 1 patient required additional access. Access was directed to the upper calyx (n ¼ 27), middle calyx (n ¼ 17), and lower calyx (n ¼ 10) through the intercostal (n ¼ 23) and subcostal (n ¼ 31) areas. Flexible nephroscopy was used in 18.5% of the procedures. Postoperative complications were observed in 9 (16.7%) of the procedures. Success rate was 66.7% after a single session of PNL and increased to 90.7% with additional treatments. Although patient demographics, preoperative imaging, and other operative measures did not have significant effect on the complication rate, stone complexity and multiplicity, in combination with flexible nephroscopy, were found to significantly affect the success rate (P ¼ .026, P ¼ .043, and P ¼ .021, respectively). However, in multivariate analysis stone multiplicity was the only factor that affected success rate (P ¼ .004). Stone parameters play an important role in achieving stone-free status in HSKs. Use of flexible nephroscopy positively affects the success rate by allowing reaching the peripherally located calices. UROLOGY 84: 1290e1294, 2014. 2014 Elsevier Inc.
T
he common renal fusion abnormality, horseshoe kidney (HSK), originates from the abnormal fusion of metanephric blastema during the embryologic period.1 Normal anatomic positioning of the kidneys is arrested by the inferior mesenteric artery due to fusion in the lower poles, resulting in malrotation, anterior displacement, and ectopy of the kidneys. The incidence of this issue has been reported to range from 1 in 400 to 1 in 666.1,2 Kidney stones are found in approximately 21%-60% of HSK cases, making them one of the most common complications.1 Features that complicate the treatment of urolithiasis in HSKs include an anteriorly displaced renal pelvis, poor renal drainage, variability in vascular structure, malrotation, and ectopic location. Although shockwave lithotripsy (SWL) and ureteroscopic laser lithotripsy (URS) are generally
Financial Disclosure: The authors declare that they have no relevant financial interests. From the Department of Urology, University of Wisconsin School of Medicine and Public Health, Madison, WI; the Department of Urology, Faculty of Medicine, Bezmialem Vakif University, Istanbul Turkey; and the Department of Urology, Kecioren Teaching and Research Hospital, Ankara, Turkey Address correspondence to: Abdulkadir Tepeler, M.D., Department of Urology 3rd floor, University of Wisconsin School of Medicine and Public Health, 1685 Highland Avenue, Madison, WI 53705. E-mail: [email protected] Submitted: June 24, 2014, accepted (with revisions): August 7, 2014
1290
ª 2014 Elsevier Inc. All Rights Reserved
recommended for small calculi, percutaneous nephrolithotomy (PNL) is the most commonly used treatment option for large and/or complex renal calculi or in cases where other treatment modalities have failed in HSK. Despite the increased success of PNL, attributable to advances in technology and refinements in operation technique, it still has a significant complication rate. Although factors affecting the success and complication rates of PNL in anatomically normal kidneys are well researched, studies exploring variables associated with outcomes of PNL in HSKs are limited. A recent study evaluating parameters related to success of PNL found that stone parameters were significant.3 To achieve better PNL results in this specific group of patients, therefore, further studies are warranted. In this study, we aimed to systematically analyze the patient- and procedure-related factors affecting the outcomes of PNL in HSKs.
METHODS After obtaining institutional review board approval, a retrospective analysis was done of patients with stones in HSKs treated with PNL in 3 referral centers between 1998 and 2013. Same surgical teams in each center performed the procedures. The following patient demographics were collected: age, gender, http://dx.doi.org/10.1016/j.urology.2014.08.008 0090-4295/14
stone-related parameters, prior therapies, preoperative imaging methods, operative details, and success and complication rates. These demographics, along with perioperative characteristics, were evaluated in detail as to whether or not they had an effect on the success and complication rates. All patients were evaluated with basic laboratory and radiologic methods. Blood count, urinalysis, creatinine, blood urea nitrogen, and coagulation profile were studied. Patients with positive urine culture were treated, as appropriate. All patients underwent a detailed radiologic assessment including intravenous urography (IVU) and/or computed tomography (CT). Stone size was measured based on the imaging method used. Stone complexity (simple, partial staghorn, complete staghorn, or complex stones) and stone multiplicity (single or multiple) were evaluated.
Operative Technique All procedures were done in prone-positioned patients under general anesthesia, with the guidance of fluoroscopy. After gaining access under fluoroscopy, the tract was dilated up to 30 Fr and an Amplatz sheath (Cook Surgical, Bloomington, IN) was inserted into the collecting system. Stone disintegration was performed using ultrasonic, pneumatic lithotripter or laser, through a 24 Fr rigid and/or 15 Fr flexible nephroscope. Additional access was created in any requirement. After endoscopic and fluoroscopic assessment of stone-free status, nephrostomy tubes were left in place. The following intraoperative variables were recorded for analysis: access site (intercostal or subcostal), access location (upper, middle, or lower pole calyx), and nephroscope used (rigid or rigid and flexible). Patients were reevaluated with laboratory tests and plain radiography of kidneys, ureters, and bladder postoperatively. Complications were graded using the Clavien Classification System.4 Nephrostomy tubes were removed on postoperative day 1 or 2. Unless there was an unresolved issue, patients were discharged after removal of the nephrostomy tubes. Stone-free status or the presence of asymptomatic fragments
