Several different procedures can be used to treat UPJ obstruction. Retrograde ureteroscopic endop... more Several different procedures can be used to treat UPJ obstruction. Retrograde ureteroscopic endopyelotomy provides a safe and adequate first line of treatment for this condition. With the advent of smaller ureteroscopes and ancillary devices, this technique has evolved to include children. Adherence to strict endourologic principles and direct visualization make retrograde ureteroscopic endopyelotomy a safe and effective treatment modality. This procedure represents an extension of the basic endoscopic skills of the urologist, creating a short learning curve and wide margin of safety.
Laparoscopic living-donor nephrectomy has gained acceptance within the transplant community. The ... more Laparoscopic living-donor nephrectomy has gained acceptance within the transplant community. The technique requires advanced laparoscopic techniques, and great care must be taken to ensure safety of the operation for the donor and transplantability of the donor kidney. Minimizing the risk of bleeding and trauma to the kidney are important features of a successful living-donor nephrectomy. Improved laparoscopic instrumentation has afforded greater safety and efficacy through technical advances. The LigaSure device was used in 124 consecutive living-donor nephrectomies beginning in 1999. A transplant database was reviewed for operative statistics including intraoperative blood loss and operating time. The LigaSure device was used to dissect and seal all venous and arterial branches. Estimated blood loss was 90 +/- 53 mL. A suction device was required in only 40 (32%) of the cases. No patient experienced postoperative bleeding. There were two donor complications: one incisional hernia and one ileus. All kidneys functioned immediately upon reperfusion. The LigaSure device is an extremely effective tool for obtaining hemostasis by sealing both venous and arterial branches of the major renal vessels. This is also effective in sealing lymphatic tissues and thereby facilitating dissection. Avoiding the use of metallic clips simplified final division of the renal artery and vein. As with any laparoscopic instrument, the anatomic geometry of the operative field may limit use based upon port placement.
Purpose: Partial nephrectomy is currently recommended for most amenable solid renal tumors, espec... more Purpose: Partial nephrectomy is currently recommended for most amenable solid renal tumors, especially if they are exophytic and less than 4 cm. We reviewed our initial experience with laparoscopic partial nephrectomy for solid renal masses without clamping the renal vasculature using a monopolar device that uses radio frequency energy with low volume saline irrigation for simultaneous blunt dissection, hemostatic sealing and coagulation of the renal parenchyma (TissueLink, TissueLink Medical, Inc., Dover, New Hampshire). Materials and Methods: From September 2002 to April 2003, 10 patients underwent transperitoneal laparoscopic partial nephrectomy, including 9 with solid renal masses and 1 with a complex cyst. In all cases the renal hilum was dissected and the renal vessels were isolated but none had renal vascular clamping. The TissueLink DS dissecting sealer or Floating Ball (Tis-sueLink Medical, Inc.) was used to dissect the tumor free bluntly, while simultaneously sealing and coagulating bleeders. Results: Mean patient age was 54.6 years (range 42 to 72). Mean American Society of Anesthesiologists score was 2.3 (range 2 to 4). Mean tumor size was 3.9 cm (range 2.1 to 8). The mass had a peripheral location in 7 cases and a central location in 3. Mean operative time was 232 minutes (range 144 to 280) and mean blood loss was 352 ml (range 20 to 1,000). One patient received blood transfusion and all tumor margins were negative. Mean hospital stay was 1.7 days (range 1 to 5) and pain medication use was minimal. One patient had a brief period of urine leakage from the lower pole calix, which was managed successfully by ureteral stenting and Foley catheter drainage of the bladder. Conclusions: Laparoscopic partial nephrectomy can be performed without renal vascular clamping. TissueLink technology allows complete tumor resection and provides adequate parenchymal hemostasis of the tumor bed. Its scant tissue charring production does not interfere with the pathological assessment of the tumor margin status.
Background and Purpose: As laparoscopic surgery has evolved, it has become part of the urologic s... more Background and Purpose: As laparoscopic surgery has evolved, it has become part of the urologic surgical armamentarium and is now used to perform more complex procedures. Carbon dioxide, used to create pneumoperitoneum, produces physiologic changes in various organs, including the kidneys. Such changes are associated with altered redox status because of the release of free radicals and changes in oxidative stress signals. It is unknown whether prolonged pneumoperitoneum is associated with an increase in oxidative stress compared with open surgery. The objective of this study was to compare oxidative stress in patients undergoing urologic laparoscopic and open operations. Patients and Methods: Urine samples were obtained immediately preoperatively, immediately postoperatively, and at 6 and 18 hours after surgery from 10 patients who underwent urologic laparoscopic surgery and 10 patients who underwent open surgery. Concentrations of the oxidative stress marker isoprostane (8iso-prostaglandin F 2a) were measured, and the results were analyzed with respect to clinical factors associated with the type of surgery. Results: Urinary isoprostane concentrations (mean ؎ SEM) in the laparoscopic and open groups showed an increase immediately after surgery to 189.0 ؎ 64.2% and 141.1 ؎ 45.8% of the preoperative values, respectively. A decrease in isoprostane was subsequently observed in both groups at 6 hours postoperatively, with preoperative values restored at 18 hours postoperatively (126.3 ؎ 19.7% and 89.5 ؎ 55.9% at 6 and 18 hours, respectively, in the laparoscopic group and 130.7 ؎ 41.6% and 88.7 ؎ 20.4% at 6 and 18 hours, respectively, in the open-surgery group). Although in both groups the peak PGF 2a concentration was observed immediately (0 hours) postoperatively, no significant differences were observed between the groups at 0, 6, and 18 hours. In the laparoscopic-surgery group, the mean increase tended to be higher and the decrease to be less prolonged than in the open-surgery group. Conclusion: Oxidative stress, as measured by urinary 8-iso-prostaglandin F2a, is produced by both laparoscopic and open urologic surgery. The findings of our nonrandomized study suggest a pattern of increased oxidative stress postoperatively with either type of surgery, with subsequent return almost to preoperative levels. Prolonged laparoscopic operative time did not affect oxidative stress levels.
Several different procedures can be used to treat UPJ obstruction. Retrograde ureteroscopic endop... more Several different procedures can be used to treat UPJ obstruction. Retrograde ureteroscopic endopyelotomy provides a safe and adequate first line of treatment for this condition. With the advent of smaller ureteroscopes and ancillary devices, this technique has evolved to include children. Adherence to strict endourologic principles and direct visualization make retrograde ureteroscopic endopyelotomy a safe and effective treatment modality. This procedure represents an extension of the basic endoscopic skills of the urologist, creating a short learning curve and wide margin of safety.
Laparoscopic living-donor nephrectomy has gained acceptance within the transplant community. The ... more Laparoscopic living-donor nephrectomy has gained acceptance within the transplant community. The technique requires advanced laparoscopic techniques, and great care must be taken to ensure safety of the operation for the donor and transplantability of the donor kidney. Minimizing the risk of bleeding and trauma to the kidney are important features of a successful living-donor nephrectomy. Improved laparoscopic instrumentation has afforded greater safety and efficacy through technical advances. The LigaSure device was used in 124 consecutive living-donor nephrectomies beginning in 1999. A transplant database was reviewed for operative statistics including intraoperative blood loss and operating time. The LigaSure device was used to dissect and seal all venous and arterial branches. Estimated blood loss was 90 +/- 53 mL. A suction device was required in only 40 (32%) of the cases. No patient experienced postoperative bleeding. There were two donor complications: one incisional hernia and one ileus. All kidneys functioned immediately upon reperfusion. The LigaSure device is an extremely effective tool for obtaining hemostasis by sealing both venous and arterial branches of the major renal vessels. This is also effective in sealing lymphatic tissues and thereby facilitating dissection. Avoiding the use of metallic clips simplified final division of the renal artery and vein. As with any laparoscopic instrument, the anatomic geometry of the operative field may limit use based upon port placement.
Purpose: Partial nephrectomy is currently recommended for most amenable solid renal tumors, espec... more Purpose: Partial nephrectomy is currently recommended for most amenable solid renal tumors, especially if they are exophytic and less than 4 cm. We reviewed our initial experience with laparoscopic partial nephrectomy for solid renal masses without clamping the renal vasculature using a monopolar device that uses radio frequency energy with low volume saline irrigation for simultaneous blunt dissection, hemostatic sealing and coagulation of the renal parenchyma (TissueLink, TissueLink Medical, Inc., Dover, New Hampshire). Materials and Methods: From September 2002 to April 2003, 10 patients underwent transperitoneal laparoscopic partial nephrectomy, including 9 with solid renal masses and 1 with a complex cyst. In all cases the renal hilum was dissected and the renal vessels were isolated but none had renal vascular clamping. The TissueLink DS dissecting sealer or Floating Ball (Tis-sueLink Medical, Inc.) was used to dissect the tumor free bluntly, while simultaneously sealing and coagulating bleeders. Results: Mean patient age was 54.6 years (range 42 to 72). Mean American Society of Anesthesiologists score was 2.3 (range 2 to 4). Mean tumor size was 3.9 cm (range 2.1 to 8). The mass had a peripheral location in 7 cases and a central location in 3. Mean operative time was 232 minutes (range 144 to 280) and mean blood loss was 352 ml (range 20 to 1,000). One patient received blood transfusion and all tumor margins were negative. Mean hospital stay was 1.7 days (range 1 to 5) and pain medication use was minimal. One patient had a brief period of urine leakage from the lower pole calix, which was managed successfully by ureteral stenting and Foley catheter drainage of the bladder. Conclusions: Laparoscopic partial nephrectomy can be performed without renal vascular clamping. TissueLink technology allows complete tumor resection and provides adequate parenchymal hemostasis of the tumor bed. Its scant tissue charring production does not interfere with the pathological assessment of the tumor margin status.
Background and Purpose: As laparoscopic surgery has evolved, it has become part of the urologic s... more Background and Purpose: As laparoscopic surgery has evolved, it has become part of the urologic surgical armamentarium and is now used to perform more complex procedures. Carbon dioxide, used to create pneumoperitoneum, produces physiologic changes in various organs, including the kidneys. Such changes are associated with altered redox status because of the release of free radicals and changes in oxidative stress signals. It is unknown whether prolonged pneumoperitoneum is associated with an increase in oxidative stress compared with open surgery. The objective of this study was to compare oxidative stress in patients undergoing urologic laparoscopic and open operations. Patients and Methods: Urine samples were obtained immediately preoperatively, immediately postoperatively, and at 6 and 18 hours after surgery from 10 patients who underwent urologic laparoscopic surgery and 10 patients who underwent open surgery. Concentrations of the oxidative stress marker isoprostane (8iso-prostaglandin F 2a) were measured, and the results were analyzed with respect to clinical factors associated with the type of surgery. Results: Urinary isoprostane concentrations (mean ؎ SEM) in the laparoscopic and open groups showed an increase immediately after surgery to 189.0 ؎ 64.2% and 141.1 ؎ 45.8% of the preoperative values, respectively. A decrease in isoprostane was subsequently observed in both groups at 6 hours postoperatively, with preoperative values restored at 18 hours postoperatively (126.3 ؎ 19.7% and 89.5 ؎ 55.9% at 6 and 18 hours, respectively, in the laparoscopic group and 130.7 ؎ 41.6% and 88.7 ؎ 20.4% at 6 and 18 hours, respectively, in the open-surgery group). Although in both groups the peak PGF 2a concentration was observed immediately (0 hours) postoperatively, no significant differences were observed between the groups at 0, 6, and 18 hours. In the laparoscopic-surgery group, the mean increase tended to be higher and the decrease to be less prolonged than in the open-surgery group. Conclusion: Oxidative stress, as measured by urinary 8-iso-prostaglandin F2a, is produced by both laparoscopic and open urologic surgery. The findings of our nonrandomized study suggest a pattern of increased oxidative stress postoperatively with either type of surgery, with subsequent return almost to preoperative levels. Prolonged laparoscopic operative time did not affect oxidative stress levels.
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Papers by FREDDY MENDEZ