The Initial Experimence Of Laparoscopic Partial Nephrectomy Under Transfixing Suture And Its Preservation Of Renal Function

Background:As the third most diagnosed genitourinary malignancy, a total of 61,560 new RCC cases and 14,080 cancer related deaths are projected to occur in the United States in 2015. The incidence of T1a renal cell carcinoma has risen steadily during the past few decades with most patients diagnosed incidentally owing to widespread utilization of ultrasound and computed tomography. The rising incidence come out with stage migration, as a result, small renal masses account for the majority of new cancers. Thus, with the evidence of comparable oncological outcomes, superior renal function preservation, laparoscopic partial nephrectomy (LPN) has supplanted laparoscopic radical nephrectomy (LRN) as the preferred treatment modality for small renal masses.Hilar control allows intraoperative visualization, which may aid in achieving a more controlled resection and precise surgical closure of the collecting system and thus minimize blood loss and secure renorrhaphy. However, hilar control can lead to well-recognized complication of renal injury and which may translate to irreversible renal functional impairment. As the treatment objectives extend well beyond tumor control, there has been a surge of interest in developing techniques that facilitate the performance of minimizing ischemia time while limiting blood loss.Presently, there is still debate over whether renal ischemic can drive ultimate postoperative function after partial nephrectomy and some questioned the necessity of "zero ischemia’" laparoscopic partial nephrectomy.Part One:The clinical analysis of 7 cases of laparoscopic partial nephrectomy under transfixing sutureObjective:To introduce our experience of laparoscopic partial nephrectomy with off-clamp under transfixing suture and evaluate the feasibility and renal function.Method:A total of 7 patients with Tla tumors underwent off-clamp laparoscopic partial nephrectomy under transfixing suture from November 2013 to January 2015. The surgery skill of off-clamp laparoscopic partial nephrectomy under transfixing suture:Before tumor resection, three needles are placed through the parenchyma, adjacent to the tumor, but not circumscribing it. The suture is cinched down one by one with pressure to block up the tumor’s blood supply to a large extent. Tumor was resected between the tumor edge and the preplaced suture.Results:All LPNs were completed without conversion to open surgery or radical nephrectomy. The mean age was 48 year, the mean tumor size was 2.2 cm. The mean operation time of off-clamp laparoscopic partial nephrectomy under transfixing suture was 89 min(76-152min). The mean estimated blood loss was 235ml (160～ 750ml). The blood urea nitrogen and serum creatinine were not significantly different before and after surgery (BUN, p=0.39; Scr, p=0.78). "zero-ischemia" laparoscopic partial nephrectomy groups are limited with small group and initial experience and long-term renal function after surgery is still awaited.Conclusion:Laparoscopic partial nephrectomy with off-clamp under transfixing suture are safe and technically feasible.Part Two:Effect of Warm Ischemia to Ultrastructures of Normal Human Renal TissueObjective:To observe the ultrastructural changes in normal human renal tissues by different time period using electronic microscope and clarify whether warm ischemia can influence the renal ultrastructure in order to evaluate the necessity of "zero-ischemia" partial nephrectomy.Method:Once the renal pedicle was blocked during the radical nephrectomy, the kidney samples were transferred to incubator. The biopsies of normal tissues were obtained every 10 minutes under the condition of ischemia and were stored in preservation solution. Transmission electron microscopy was used to observe the ultrastructural changes. The changes of microvillus of renal tubule, glomerular basement membrane and podocytes were recorded.Results:At the ulrastructural level, there were only some little changes and did not observe serious irreversible lesions when the ischemia time less than 20min. However,20-40min ischemia did cause some irreversible lesions, such as the podocytes preserved their integrity, and atrophy of the board-in-brush. Disintegration of the slit diaphragms was also observed. The endothelial cells were exhibiting early signs of cellular necrosis.40-60 min of warm ischemia cause serious detrimental effects at the ultrastructural level. Total loss of cellular differentiation, atrophy of the board-in-brush, necrosis, apoptotic bodies, flattening of the glomerular basement membrane, and foot process effacement were observed.Outcomes:Warm ischemia time during LPN is associated with the ultrastructural changes in kidney tissue and the severity of the lesions was dependent on the duration of ischemia. Therefore, it is of great clinical significance to carry out "zero ischemic" laparoscopic partial nephrectomy to minimize warm ischemia time.Part Three:Laparoscopic Partial Nephrectomy versus Radical Nephrectomy for Renal Tumors:A Meta-analysis of Renal FunctionsObjective:The widespread use of laparoscopic partial nephrectomy has led to preservation of functional renal parenchyma, however, the benefits of laparoscopic partial nephrectomy in terms of renal function and cardiovascular outcomes remain controversial in light of the European Organization for the Research and Treatment of Cancer trial in 2014. Thus a meta-analysis was performed to reconcile the conflicting results.Materials and Methods:PubMed, Embase and the Cochrane Library were searched from inception to July 2015, databases with all relevant comparative studies were included. Mantel-Haenszel method with random effects models were used to determine the pooled hazard ratios for each outcome.Results:26 studies were pooled for new-onset chronic kidney disease, and 6 studies were pooled for cardiovascular outcomes. According to pooled estimates, LPN correlated with a 73% risk reduction of new-onset chronic kidney disease in all included patients (HR 0.27, p<0.0001), a 65% risk reduction in patients with tumors >4cm (HR 0.35, p<0.0001) compared to LRN. While there’re no significant difference between both groups regarding postsurgery cardiovascular events (HR: 0.86, p=0.238) and cardiovascular death (HR:0.79, p=0.196). Though with inherent selection biases, the pooled estimates were roughly robust in sensitivity and subgroup analyses.Conclusion:Our findings suggest that LPN lowers the postoperative new-onset chronic kidney disease. Nevertheless, the protection of renal function by partial nephrectomy did not reduce the risk of cardiovascular outcomes. However, this result remains controversial and additional large-scale evaluations are warranted.