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Normal Ureter Size on Unenhanced Helical CT
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UROLITHIASIS, ENDOUROLOGY AND LAPAROSCOPY
intrarenal pressures were measured at all three settings using the URS passed without a sheath and then with the URS passed through the various sheaths positioned at the distal ureter, middle ureter, and renal pelvis. Results. With all of the sheaths, intrapelvic pressure remained low (less than 30 cm H2O), and there was a 35% to 80% increase in irrigant flow versus the control unsheathed URS. With the sheath in place, the majority of the irrigant drained alongside the URS and out the sheath. Flow and pressure with the 12/14F sheath were equivalent to the 14/16F sheath. Conclusions. The 12/14F access sheath provides for maximum flow of irrigant while maintaining a low intrarenal pelvic pressure. Even with an irrigation pressure of 200 cm H2O, renal pelvic pressure remained below 20 cm H2O. Editorial Comment: You can’t hit what you can’t see. While there has been much controversy over the use of ureteral access sheaths during ureteroscopy, there is one undeniable finding—at a given irrigant pressure the flow of irrigant with a sheath in place is far greater and intrapelvic pressure is far less than without an access sheath. The major benefit to the access sheath is for those situations in which multiple passes of the flexible ureteroscope are anticipated, such as biopsy and treatment of a low grade ureteral tumor. In addition, depending on surgeon preference in stone therapy, if the goal is to fragment and evacuate fragments, then a sheath is extremely helpful. Basketed stones pulled into the sheath pose no threat to ureteral integrity, and multiple passes of the flexible ureteroscope are easily and safely accomplished. Ralph V. Clayman, M.D. Normal Ureter Size on Unenhanced Helical CT N. ZELENKO, D. COLL, A. T. ROSENFELD AND R. C. SMITH, Weill Medical College of Cornell University, Department of Radiology, New York-Presbyterian Hospital, Fordham University School of Law, New York, and Department of Diagnostic Imaging, Yale University School of Medicine, New Haven, Connecticut AJR Am J Roentgenol, 182: 1039 –1041, 2004 OBJECTIVE. Unenhanced helical CT is the imaging method of choice when evaluating patients with acute flank pain and suspected ureterolithiasis. In addition to directly identifying stones in the lumen of the ureter, CT secondary signs of obstruction such as ureteral dilatation are frequently present and can be helpful in establishing a diagnosis. The purposes of this study were to define ureteral dilatation on unenhanced helical CT and determine the range of normal ureter size. MATERIALS AND METHODS. We retrospectively reviewed the unenhanced helical CT studies of 212 consecutive patients with acute flank pain whose CT scans showed acute ureterolithiasis. The size of the ureter was determined on the asymptomatic side as well as on the obstructed side. Mean ureteral diameter was determined as the largest transverse dimension along the course of the ureter beginning 1–2 cm below the ureteropelvic junction. RESULTS. The mean size of ureters on the asymptomatic side was 1.8 mm with a standard deviation (SD) of 0.9 mm. The mean size of ureters on the obstructed side was 7 mm with an SD of 3.2 mm. In 96% of patients, the ureter diameter on the asymptomatic side was 3 mm or smaller. CONCLUSION. Three millimeters should be considered the upper limit of normal size for nonobstructed ureters on unenhanced helical CT. Editorial Comment: How small should a ureteroscope be to traverse most ureters? The answer based on this study would be smaller than 9Fr (ie 3 mm), as this was the upper limit of a normal sized ureter in 96% of 212 study patients. Indeed, mean ureteral size on the normal side was only 5.4Fr. This finding would explain why even the 7.5Fr flexible ureteroscopes, which invariably ramp up to a mid shaft size of 8.5Fr to 9Fr, may not pass up all ureters. The other more obvious implication of this study is that any ureter measuring more than 3 mm on computerized tomography is likely obstructed or diseased. Ralph V. Clayman, M.D. A Comparison of Extracorporeal Shock Wave Lithotripsy and Ureteroscopy Under Intravenous Sedation for the Management of Distal Ureteric Calculi D. H. HOSKING, W. E. SMITH AND S. E. MCCOLM, Department of Surgery, Section of Urology, University of Manitoba and Adult Ambulatory Care, Section of Urology, Health Sciences Centre, Winnipeg, Manitoba, Canada Can J Urol, 10: 1780 –1784, 2003 Introduction: We have performed a study to compare shock wave lithotripsy (SWL) and ureteroscopy under intravenous sedation for the management of distal ureteric calculi. Materials and methods: Patient tolerance, procedure times and treatment outcomes were prospectively evaluated in 110 patients undergoing 138 SWL treatments, and 172 patients undergoing ureteroscopy under intravenous sedation for the management of distal ureteric calculi. Results: Men tolerated SWL better than ureteroscopy. Over 90% of women tolerated both procedures well.
UROLITHIASIS, ENDOUROLOGY AND LAPAROSCOPY
intrarenal pressures were measured at all three settings using the URS passed without a sheath and then with the URS passed through the various sheaths positioned at the distal ureter, middle ureter, and renal pelvis. Results. With all of the sheaths, intrapelvic pressure remained low (less than 30 cm H2O), and there was a 35% to 80% increase in irrigant flow versus the control unsheathed URS. With the sheath in place, the majority of the irrigant drained alongside the URS and out the sheath. Flow and pressure with the 12/14F sheath were equivalent to the 14/16F sheath. Conclusions. The 12/14F access sheath provides for maximum flow of irrigant while maintaining a low intrarenal pelvic pressure. Even with an irrigation pressure of 200 cm H2O, renal pelvic pressure remained below 20 cm H2O. Editorial Comment: You can’t hit what you can’t see. While there has been much controversy over the use of ureteral access sheaths during ureteroscopy, there is one undeniable finding—at a given irrigant pressure the flow of irrigant with a sheath in place is far greater and intrapelvic pressure is far less than without an access sheath. The major benefit to the access sheath is for those situations in which multiple passes of the flexible ureteroscope are anticipated, such as biopsy and treatment of a low grade ureteral tumor. In addition, depending on surgeon preference in stone therapy, if the goal is to fragment and evacuate fragments, then a sheath is extremely helpful. Basketed stones pulled into the sheath pose no threat to ureteral integrity, and multiple passes of the flexible ureteroscope are easily and safely accomplished. Ralph V. Clayman, M.D. Normal Ureter Size on Unenhanced Helical CT N. ZELENKO, D. COLL, A. T. ROSENFELD AND R. C. SMITH, Weill Medical College of Cornell University, Department of Radiology, New York-Presbyterian Hospital, Fordham University School of Law, New York, and Department of Diagnostic Imaging, Yale University School of Medicine, New Haven, Connecticut AJR Am J Roentgenol, 182: 1039 –1041, 2004 OBJECTIVE. Unenhanced helical CT is the imaging method of choice when evaluating patients with acute flank pain and suspected ureterolithiasis. In addition to directly identifying stones in the lumen of the ureter, CT secondary signs of obstruction such as ureteral dilatation are frequently present and can be helpful in establishing a diagnosis. The purposes of this study were to define ureteral dilatation on unenhanced helical CT and determine the range of normal ureter size. MATERIALS AND METHODS. We retrospectively reviewed the unenhanced helical CT studies of 212 consecutive patients with acute flank pain whose CT scans showed acute ureterolithiasis. The size of the ureter was determined on the asymptomatic side as well as on the obstructed side. Mean ureteral diameter was determined as the largest transverse dimension along the course of the ureter beginning 1–2 cm below the ureteropelvic junction. RESULTS. The mean size of ureters on the asymptomatic side was 1.8 mm with a standard deviation (SD) of 0.9 mm. The mean size of ureters on the obstructed side was 7 mm with an SD of 3.2 mm. In 96% of patients, the ureter diameter on the asymptomatic side was 3 mm or smaller. CONCLUSION. Three millimeters should be considered the upper limit of normal size for nonobstructed ureters on unenhanced helical CT. Editorial Comment: How small should a ureteroscope be to traverse most ureters? The answer based on this study would be smaller than 9Fr (ie 3 mm), as this was the upper limit of a normal sized ureter in 96% of 212 study patients. Indeed, mean ureteral size on the normal side was only 5.4Fr. This finding would explain why even the 7.5Fr flexible ureteroscopes, which invariably ramp up to a mid shaft size of 8.5Fr to 9Fr, may not pass up all ureters. The other more obvious implication of this study is that any ureter measuring more than 3 mm on computerized tomography is likely obstructed or diseased. Ralph V. Clayman, M.D. A Comparison of Extracorporeal Shock Wave Lithotripsy and Ureteroscopy Under Intravenous Sedation for the Management of Distal Ureteric Calculi D. H. HOSKING, W. E. SMITH AND S. E. MCCOLM, Department of Surgery, Section of Urology, University of Manitoba and Adult Ambulatory Care, Section of Urology, Health Sciences Centre, Winnipeg, Manitoba, Canada Can J Urol, 10: 1780 –1784, 2003 Introduction: We have performed a study to compare shock wave lithotripsy (SWL) and ureteroscopy under intravenous sedation for the management of distal ureteric calculi. Materials and methods: Patient tolerance, procedure times and treatment outcomes were prospectively evaluated in 110 patients undergoing 138 SWL treatments, and 172 patients undergoing ureteroscopy under intravenous sedation for the management of distal ureteric calculi. Results: Men tolerated SWL better than ureteroscopy. Over 90% of women tolerated both procedures well.