Renal Function Outcomes in Patients Undergoing Open or Laparoscopic Radical Nephrectomy

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1 Renal Function Outcomes in Patients Undergoing Open or Laparoscopic Radical Nephrectomy Koo Han Yoo, Hyung-Lae Lee, Sung-Goo Chang, Seung Hyun Jeon From the Department of Urology, Kyung Hee University School of Medicine, Seoul, Korea Purpose: We compared renal function outcomes in patients undergoing open or laparoscopic radical nephrectomy. Materials and Methods: Seventy-one patients undergoing open or laparoscopic radical nephrectomy for kidney disease with a normal contralateral kidney were identified between January 2004 and December Renal function was calculated by using the Cockcroft-Gault formula. Serial renal functions were checked from the day before surgery to 1 year after surgery. Exclusion criteria were preexisting renal insufficiency, urinary stone disease, and pancreatic and liver disorders. Results: Forty-one and 30 patients were treated with open radical nephrectomy or laparoscopic radical nephrectomy, respectively. The operative time and urine output of patients who underwent open and laparoscopic radical nephrectomy were 211.7±5.8 and 330.8±15.6 and 196.4±19.6 and 130.7±12.1, respectively (p=0.001, p=0.013). The glomerular filtration rates of patients who underwent open or laparoscopic radical nephrectomy were insignificant from baseline to postoperative day 360 (p>0.05). Conclusions: No significant differences in renal function were detected in the groups of patients who underwent open or laparoscopic radical nephrectomy from baseline to long-term follow-up. (Korean J Urol 2009;50: ) Key Words: Laparoscopy, Glomerular filtration rate, Nephrectomy Korean Journal of Urology Vol. 50 No. 6: , June 2009 DOI: /kju Received:March 10, 2009 Accepted:May 27, 2009 Correspondence to: Seung Hyun Jeon Deaprtment of Urology, Kyung Hee University Medical Center, 1, Hoegi-dong, Dongdaemun-gu, Seoul , Korea TEL: FAX: juro@khu.ac.kr C The Korean Urological Association, 2009 INTRODUCTION Since the initial report in 1991 by Clayman et al, 1 laparoscopic nephrectomy has been popularized for various kidney diseases. The major advantages of laparoscopic nephrectomy over open nephrectomy include decreased perioperative morbidity, less blood loss, shorter hospital stays, and quicker convalescence. 2,3 While complication rates from laparoscopic procedures are comparable to those of open procedures, 4-6 the presentation of these complications can be quite different following laparoscopic versus open nephrectomy. Intraoperative oliguria is common during laparoscopy, but is transient and resolves after desufflation. 7,8 The effects of pneumoperitoneum at 15 mmhg on renal function during short laparoscopic operations has been shown to be minimal, but patients with pre-existing renal dysfunction or patients undergoing prolonged laparoscopic operations might be at risk for postoperative renal impairment. 9 Laparoscopic surgeries commonly increase the operative time and there are adverse effects of a pneumoperitoneum on urine output and renal function; however, there are no long-term studies regarding renal function after laparoscopic surgery. The purpose of our trial was to compare the renal function outcomes in patients undergoing open and laparoscopic radical nephrectomy. MATERIALS AND METHODS Seventy-one patients between January 2004 and December 2007 undergoing open or laparoscopic radical nephrectomy for kidney disease were identified. The operations included open radical and laparoscopic radical nephrectomies. Intraabdominal gas pressure was 15 mmhg during laparoscopic operation. 581

2 582 Korean Journal of Urology vol. 50, , June 2009 Preoperative data, including patient co-morbidities, such as hypertension, diabetes mellitus, cerebrovascular disease, renal mass characteristics, body mass index, and intraoperative data, including operative time, estimated blood loss, approach method were obtained retrospectively. The contralateral kidney was assessed on computed tomography (CT scan) and excluded if abnormal findings were present. Exclusion criteria were pre-existing renal insufficiency (glomerular filtration rate<60 ml/min.), uncontrolled diabetes mellitus, urinary stone disease, contralateral ureteropelvic junction stricture, liver disorders, conversion to open surgery, and intraoperative complications such as pancreatic, bowel, splenic injury. The glomerular filtration rate as renal function was obtained using serum creatinine on the day prior to surgery, the day of surgery, and postoperative days 1, 2, 3, 7, 30, 90, 180, and 360. The glomerular filtration rate was calculated using the Cockcroft-Gault formula (creatinine clearance [ml/min]=[140- age]xlean body weight [kg]/plasma creatinine [ml/dl])x72x [0.85 if women]). The groups were compared to determine whether there was a significant difference between changes in renal function following open and laparoscopic radical nephrectomy. The mean differences between the two independent groups with nonparametric data were analyzed using Mann-Whitney U tests and the sex and co-morbidities were analyzed using Fisher s exact test. All analyses were performed with SPSS p-value of less than 0.05 was considered statistically significant. RESULTS Forty-one and 30 patients were treated with open and laparoscopic radical nephrectomy, respectively. The number and types of nephrectomies were as follows: open radical (41 cases) and laparoscopic radical (30 cases). The median ages of the patients were 56 years (range, years) and 54 years (range, years) for open and laparoscopic surgery, respectively. Operation times were 211 minutes (range, minutes) and 330 minutes (range, minutes), and urine outputs were 196 ml/hr (range, ml/hr) and 130 ml/hr (range, ml/hr) and estimated blood losses were 729 ml (range, 350-2,600 ml) and 645 ml (range, ml), open and laparoscopic nephrectomy, respectively (p=0.001, p=0.013, p=0.139). Table 1 shows the patient and operative data for each of these procedure groups. On postoperative days 3 and 7, the glomerular filtration rates of patients who underwent open and laparoscopic nephrectomy were and ml/min., and and ml/min., respectively. On postoperative day 360, the glomerular filtration rates of patients who underwent open and laparoscopic nephrectomy were and ml/min., respectively. Table 2 presents the serial glomerular filtration rates differences from the baseline of the two groups. In process of time, the differences of glomerular filtration rates increased, but there was no statistical significance (p<0.05). These results indicate that the pneumoperitoneum did not affect a decline in renal function for a short and long period. Table 1. The characteristics of 71 cases of open and laparoscopic radical nephrectomy ORN (n=41) LRN (n=30) p-value Median age in years (range) 56 (43-74) 54 (48-68) a Sex (male:female) 23:18 14: b Body mass index (kg/m 2 ) 25.0 ( ) 24.6 ( ) a Urine output (ml/hr) 196 (85-350) 130 (55-195) a Operative time (minute) 211 ( ) 330 ( ) a Estimated blood loss (ml) 729 (350-2,600) 645 ( ) a Co-morbidities Hypertension b Diabetes mellitus b Cerebrovascular disease b Hepatitis b ORN: open radical nephrectomy, LRN: laparoscopic radical nephrectomy, a : Mann-Whitney U test, b : Fisher s exact test

3 Koo Han Yoo, et al:renal Function following Open and Laparoscopic Nephrectomy 583 Table 2. Renal function after open or laparoscopic radical nephrectomy Creatinine clearance (ml/min.) ORN (n=41) LRN (n=30) p-value PRE-DOS 10.24± ± a PRE-POD ± ± a PRE-POD ± ± a PRE-POD ± ± a PRE-POD ± ± a PRE-POD ± ± a PRE-POD ± ± a PRE-POD ± ± a PRE-POD ± ± a ORN: open radical nephrectomy, LRN: laparoscopic radical nephrectomy, PRE: preoperative, DOS: day of surgery, POD: postoperative day, a : Mann-Whitney U test DISCUSSION Removal of one kidney increases the serum creatinine by up to 20%, with functional hypertrophy of the remaining normal contralateral kidney. 10 So, we excluded pre-existing renal insufficiency, uncontrolled diabetes mellitus, urinary stone disease, contralateral ureteropelvic junction strictures, liver disorders, and conversion to open surgery, and assessed the contralateral kidney using CT scan to obtain a pure glomerular filtration rate. According to our results, a significant decline in renal function was detected in the group of patients undergoing laparoscopic nephrectomy rather than open nephrectomy in the short-term, but there was no difference in renal function between the two groups in the long-term. Commonly, acute increased intraabdominal pressure has an adverse effect on renal function. Rapid elevation of intraabdominal pressure (>25 mmhg) can result in acute renal insufficiency and abdominal decompression causes immediate improvement. 11 Increasing intraabdominal pressure from 0-20 mmhg decreases the glomerular filtration rate by 21% and increases renal vascular resistance by 555%. 12 Urinary N-acetyl- B-D-glucosaminidase is an indicator of potential renal tubular damage, and a pneumoperitonem results in a considerably higher excretion of N-acetyl-B-D-glucosaminidase in patients who underwent laparoscopic cholecystectomy compared with patients who underwent cholecystectomy performed by an abdominal wall lift method. 13 The adverse effects of increased intraabdominal pressure on intraoperative urine output have been reported during laparoscopic surgery. 7,8,13 If abdominal pressure is maintained constantly at 15 mmhg, oliguria has been reported, even during short laparoscopic procedures. 8 The mechanism for intraoperative oliguria during laparoscopy has been implicated with increased intraabdominal pressure, which has a direct compressive effect on the kidney parenchyma and renal vessels. The direct pressure effect on the renal vasculature results in decreased renal blood flow. 14 In a swine study, elevated intraabdominal pressure increased plasma renin activation and aldosterone levels and abdominal decompression decreased both of these levels. 15 But the reduction in intraoperative urinary output did not adversely affect renal function. 16 No change in BUN or serum creatinine levels was observed after laparoscopic surgery. In addition, creatinine clearance was in the normal range after laparoscopic surgery on both postoperative days 1 and 2. After laparoscopic adrenalectomy, when compared with gasless laparoscopic adrenalectomy, there was no change in serum creatinine. 17 In our study, hourly urine output was decreased in the laparoscopic surgery group compared to the open surgery group, but a significant decline in the glomerular filtration rate was not detected in the group of patients who underwent laparoscopic surgery. A pneumoperitoneum does not affect renal function in the short-term and the long-term follow-up period. Despite the intraoperative oliguria, a prolonged pneumoperitoneum was clinically safe with respect to renal function as there was no alteration in postoperative renal function including chronic kidney disease patients Colombo et al 10 reviewed renal function outcomes retrospectively after laparoscopic or open radical nephrectomy. They concluded that there was no difference in renal functional outcomes between the groups who underwent unilateral laparoscopic and open radical nephrectomy at a median follow-up

4 584 Korean Journal of Urology vol. 50, , June 2009 of 51 months. The serum creatinine increased by up to 20%, with functional hypertrophy of the remaining kidney, which can compensate for the decrease in the overall glomerular filtration rate after removal of one kidney. Baseline risk factors, such as age, hypertension, diabetes, and obesity were not significantly associated with postoperative renal function based on univariate analysis. McKiernan et al 21 showed a mean increase in serum creatinine of 0.5 mg/dl in 173 patients who had undergone radical nephrectomy after a follow-up of 25 months. The limitations of Cockcroft-Gault formula using serum creatinine as opposed to timed urine collections are that the equation systemically underestimates glomerular filtration rate in healthy persons with high-normal serum creatinine levels, and overestimates the prevalence of a reduced glomerular filtration rate in the general population. And even though glomerular filtration rate estimating equations contain a variable for sex, it remains unclear whether men or women are at higher risk for a reduced glomerular filtration rate. The weaknesses of this study include its retrospective design, small sample size, effect of one kidney removal, and lack of other laboratory findings, such as renin and aldosterone. Further studies are required to examine other mechanisms that might account for the decreased renal function and reduced urine output during laparoscopic surgery, such as reduced renal blood flow, decreased perfusion of the renal cortex and medulla, or perhaps an alteration in the expression of mediators related to renal blood flow. CONCLUSIONS A significant difference in renal function was not detected in the group of patients who underwent open and laparoscopic radical nephrectomy from baseline to long-term follow-up. REFERENCES 1. Clayman RV, Kavoussi LR, Soper NJ, Dierks SM, Meretyk S, Darcy MD, et al. Laparoscopic nephrectomy: initial case report. J Urol 1991;146: Saranchuk JW, Savage SJ. Laparoscopic radical nephrectomy: current status. BJU Int 2005;95(Suppl 2): Dunn MD, Portis AJ, Shalhav AL, Elbahnasy AM, Heidorn C, McDougall EM, et al. Laparoscopic versus open radical nephrectomy: a 9-year experience. J Urol 2000;164: Gill IS, Matin SF, Desai MM, Kaouk JH, Steinberg A, Mascha E, et al. Comparative analysis of laparoscopic versus open partial nephrectomy for renal tumors in 200 patients. J Urol 2003;170: Rassweiler J, Seemann O, Schulze M, Teber D, Hatzinger M, Frede T. Laparoscopic versus open radical prostatectomy: a comparative study at a single institution. J Urol 2003;169: Basillote JB, Abdelshehid C, Ahlering TE, Shanberg AM. Laparoscopic assisted radical cystectomy with ileal neobladder: a comparison with the open approach. J Urol 2004;172: McDougall EM, Monk TG, Wolf JS Jr, Hicks M, Clayman RV, Gardner S, et al. The effect of prolonged pneumoperitoneum on renal function in an animal model. J Am Coll Surg 1996;182: Koivusalo AM, Kellokumpu I, Scheinin M, Tikkanen I, Halme L, Lindgren L. Randomized comparison of the neuroendocrine response to laparoscopic cholecystectomy using either conventional or abdominal wall lift techniques. Br J Surg 1996;83: London ET, Ho HS, Neuhaus AM, Wolfe BM, Rudich SM, Perez RV. Effect of intravascular volume expansion on renal function during prolonged CO2 pneumoperitoneum. Ann Surg 2000;231: Colombo JR Jr, Haber GP, Jelovsek JE, Lane B, Novick AC, Gill IS. Seven years after laparoscopic radical nephrectomy: oncologic and renal functional outcomes. Urology 2008;71: Kron IL, Harman PK, Nolan SP. The measurement of intra-abdominal pressure as a criterion for abdominal re-exploration. Ann Surg 1984;199: Harman PK, Kron IL, McLachlan HD, Freedlender AE, Nolan SP. Elevated intra-abdominal pressure and renal function. Ann Surg 1982;196: Koivusalo AM, Kellokumpu I, Ristkari S, Lindgren L. Splanchnic and renal deterioration during and after laparoscopic cholecystectomy: a comparison of the carbon dioxide pneumoperitoneum and the abdominal wall lift method. Anesth Analg 1997;85: Junghans T, Böhm B, Gründel K, Schwenk W. Effects of pneumoperitoneum with carbon dioxide, argon, or helium on hemodynamic and respiratory function. Arch Surg 1997;132: Bloomfield GL, Blocher CR, Fakhry IF, Sica DA, Sugerman HJ. Elevated intra-abdominal pressure increases plasma renin activity and aldosterone levels. J Trauma 1997;42: Nguyen NT, Perez RV, Fleming N, Rivers R, Wolfe BM. Effect of prolonged pneumoperitoneum on intraoperative urine output during laparoscopic gastric bypass. J Am Coll Surg 2002;195: Nishio S, Takeda H, Yokoyama M. Changes in urinary output during laparoscopic adrenalectomy. BJU Int 1999;83: Baik S, Rho J, Kim CS. Comparison of hand-assisted laparos-

5 Koo Han Yoo, et al:renal Function following Open and Laparoscopic Nephrectomy 585 copic donor nephrectomy with open donor nephrectomy. Korean J Urol 2005;46: Choi HW, Jung JW, Jung JU, Cho HJ, Hong SH, Kim JC, et al. Feasibility and safety of performing hand-assisted laparoscopic donor nephrectomy for patients with multiple renal arteries. Korean J Urol 2008;49: Yoo KH, Jeon SH, Kim TW, Lee HL. Laparoscopic radical nephrectomy and nephroureterectomy in dialysis patients. Korean J Urol 2007;48: McKiernan J, Simmons R, Katz J, Russo P. Natural history of chronic renal insufficiency after partial and radical nephrectomy. Urology 2002;59:816-20