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Minimally Invasive Robotic Kidney Transplantation for Obese Patients Previously Denied Access to Transplantation

2013; Elsevier BV; Volume: 13; Issue: 3 Linguagem: Inglês

10.1111/ajt.12078

1600-6143

José Oberholzer, Pier Cristoforo Giulianotti, Kirstie K. Danielson, Mario Spaggiari, Lorena Bejarano‐Pineda, Francesco M. Bianco, Ivo Tzvetanov, Subhashini Ayloo, Hoonbae Jeon, Raquel Garcı́a-Roca, J. Thielke, Ignatius Tang, Sanjeev Akkina, Bryan N. Becker, Katie Kinzer, Amit R. Patel, Enrico Benedetti,

Organ Donation and Transplantation

The authors report results on a new robotic kidney transplantation technique for obese patients that has comparable patient outcomes compared to an open procedure. The authors report results on a new robotic kidney transplantation technique for obese patients that has comparable patient outcomes compared to an open procedure. Obese patients with end-stage renal disease (ESRD) are often excluded from kidney transplantation due to concerns about surgical site infections. To reduce infections, we developed a robotic kidney transplantation method for obese recipients. From June 2009 to December 2011, a prospective cohort of 39 obese patients underwent robotic kidney transplantation at a single center. The outcomes of patients with at least 6 months of follow-up (n = 28) were compared to a frequency-matched retrospective cohort of obese patients who underwent open kidney transplantation from 2004 to 2009 (n = 28). The 28 robotic patients were predominately African American (46.4%) or Hispanic (35.7%), with a mean age of 47.9 ± 10.7 years, similar to the control group. BMI in the robotic group was 42.6 ± 7.8 kg/m2 compared to 38.1 ± 5.4 kg/m2 in the control group (p = 0.02). There were no surgical site infections in the robotic group (0/28), while 28.6% (8/28) in the control group developed an infection (p = 0.004). Six-month creatinine (1.5 ± 0.4 vs. 1.6 ± 0.6 mg/dL; p = 0.47), and patient and graft survival (100%) were comparable between the two groups. Outcomes following robotic surgery compared favorably to conventional transplantation. Robotic surgery may therefore enable obese patients with ESRD to access kidney transplantation and may thereby reduce health disparities in groups with a high prevalence of obesity and ESRD. Epidemiological data indicate that 20–50% of patients on dialysis for end-stage renal disease (ESRD) are obese (body mass index [BMI] ≥30 kg/m2) (1U.S. Renal Data System. USRDS 2011Annual Data Report: Atlas of Chronic Kidney Disease and End-Stage Renal Disease in the United States.. National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD2011Google Scholar). Obese patients with chronic renal failure have longer wait times until kidney transplantation (2Segev DL Simpkins CE Thompson RE Locke JE Warren DS Montgomery RA Obesity impacts access to kidney transplantation.J Am Soc Nephrol. 2008; 19: 349-355Crossref PubMed Scopus (183) Google Scholar) and inferior patient outcomes (3Modlin CS Flechner SM Goormastic M et al.Should obese patients lose weight before receiving a kidney transplant?.Transplantation. 1997; 64: 599-604Crossref PubMed Scopus (144) Google Scholar, 4Meier-Kriesche HU Vaghela M Thambuganipalle R Friedman G Jacobs M Kaplan B The effect of body mass index on long-term renal allograft survival.Transplantation. 1999; 68: 1294-1297Crossref PubMed Scopus (136) Google Scholar, 5Pischon T Sharma AM Obesity as a risk factor in renal transplant patients.Nephrol Dial Transplant. 2001; 16: 14-17Crossref PubMed Scopus (76) Google Scholar, 6Meier-Kriesche HU Arndorfer JA Kaplan B The impact of body mass index on renal transplant outcomes: A significant independent risk factor for graft failure and patient death.Transplantation. 2002; 73: 70-74Crossref PubMed Scopus (476) Google Scholar, 7Meier-Kriesche HU Kaplan B Waiting time on dialysis as the strongest modifiable risk factor for renal transplant outcomes: A paired donor kidney analysis.Transplantation. 2002; 74: 1377-1381Crossref PubMed Scopus (627) Google Scholar). In the United States, for example, patients with a BMI < 25 kg/m2 have a median wait time of 39 months for a deceased donor kidney transplantation compared to 59 months in patients with a BMI > 40 kg/m2 (2Segev DL Simpkins CE Thompson RE Locke JE Warren DS Montgomery RA Obesity impacts access to kidney transplantation.J Am Soc Nephrol. 2008; 19: 349-355Crossref PubMed Scopus (183) Google Scholar). Higher BMIs in kidney transplant recipients are associated with excess risk of surgical site infections (SSIs), which negatively impact graft survival (8Lynch RJ Ranney DN Shijie C Lee DS Samala N Englesbe MJ Obesity, surgical site infection, and outcome following renal transplantation.Ann Surg. 2009; 250: 1014-1020Crossref PubMed Scopus (190) Google Scholar). Obesity is also associated with comorbidities such as diabetes, although data on whether obesity increases mortality in kidney transplanted patients remain unclear (8Lynch RJ Ranney DN Shijie C Lee DS Samala N Englesbe MJ Obesity, surgical site infection, and outcome following renal transplantation.Ann Surg. 2009; 250: 1014-1020Crossref PubMed Scopus (190) Google Scholar,9Aalten J Christiaans MH de Fijter H et al.The influence of obesity on short- and long-term graft and patient survival after renal transplantation.Transpl Int. 2006; 19: 901-907Crossref PubMed Scopus (101) Google Scholar). Provider perceptions of these risks accompanied by the expectation of some centers to give obese patients time to lose weight are the main reasons why a number of transplant centers are reluctant to list obese patients for transplantation (2Segev DL Simpkins CE Thompson RE Locke JE Warren DS Montgomery RA Obesity impacts access to kidney transplantation.J Am Soc Nephrol. 2008; 19: 349-355Crossref PubMed Scopus (183) Google Scholar,10Pham PT Pham PA Pham PC Parikh S Danovitch G Evaluation of adult kidney transplant candidates.Semin Dial. 2010; 23: 595-605Crossref PubMed Scopus (42) Google Scholar). Unfortunately, many of these obese patients have diabetes and hypertension likely secondary to their obesity (11Sugerman HJ Wolfe LG Sica DA Clore JN Diabetes and hypertension in severe obesity and effects of gastric bypass-induced weight loss.Ann Surg. 2003; 237: 751-758Crossref PubMed Scopus (440) Google Scholar) and such patients who remain on dialysis have a very high mortality rate. The 5-year mortality rate for diabetic and hypertensive dialysis patients is 75 and 70%, respectively (1U.S. Renal Data System. USRDS 2011Annual Data Report: Atlas of Chronic Kidney Disease and End-Stage Renal Disease in the United States.. National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD2011Google Scholar). A recent study demonstrated that obese patients who did not present with any SSIs had the same kidney transplant success rate as patients with a normal BMI (8Lynch RJ Ranney DN Shijie C Lee DS Samala N Englesbe MJ Obesity, surgical site infection, and outcome following renal transplantation.Ann Surg. 2009; 250: 1014-1020Crossref PubMed Scopus (190) Google Scholar). If surgical procedures could be developed that prevent SSIs and demonstrate successful outcomes, transplant centers may become less reluctant to list obese patients for kidney transplantation. Although any benefit would still have to be weighed against potential increased risks from obesity-related comorbidities. The prevalence of obesity and ESRD is higher among racial and ethnic minority populations, including African Americans and Hispanics, compared to non-Hispanic whites (12Institute of MedicineUnequal Treatment: Confronting Racial and Ethnic Disparities in Health Care.. The National Academies Press, Washington, D.C.2002Google Scholar, 13Coresh J Selvin E Stevens LA et al.Prevalence of chronic kidney disease in the United States.JAMA. 2007; 298: 2038-2347Crossref PubMed Scopus (3926) Google Scholar, 14Mehrotra R Kermah D Fried L Adler S Norris K Racial differences in mortality among those with CKD.J Am Soc Nephrol. 2008; 19: 1403-1410Crossref PubMed Scopus (113) Google Scholar, 15US Centers for Disease Control. Fact sheet: Health disparities in obesity 2011. http://www.cdc.gov/minorityhealth/reports/CHDIR11/FactSheets/Obesity.pdf. Accessed February 12, 2012.Google Scholar). These observations suggest developing kidney transplantation options for obese patients with ESRD may also help to reduce health disparities in racial and ethnic minorities. We therefore developed a new, minimally invasive, robotic kidney transplantation method using a short epigastric incision. This method avoids any incision in the infection prone lower quadrants of the abdomen. We hypothesized a priori that the robotic approach would reduce SSIs and improve outcomes in obese kidney transplant patients. Herein, we present our experience and outcomes of the patients undergoing minimal invasive, robotic kidney transplantation at a single institution compared to patients who underwent the conventional open procedure. From June 2009 to December 2011, a prospective cohort of 39 obese patients with ESRD underwent robotic kidney transplantation at the University of Illinois Hospital & Health Sciences System. Twenty eight of these patients completed a follow-up period of at least 6 months after transplant. We compared the posttransplant outcomes from these 28 patients with those of a retrospective cohort control group of 28 obese patients undergoing standard open kidney transplantation prior to June 2009 at our institution, also with at least 6 months of follow-up. They were frequency matched to the robotic surgery group on the following variables, listed in order of priority: BMI (30 kg/m2 ≤ BMI < 35 kg/m2 [obese], or BMI ≥35 kg/m2 [morbidly obese]); race (patient reported non-Hispanic white, Hispanic, African American); ABO incompatibility (yes/no); cross-match positivity (yes/no); gender (male/female); age; living/deceased donation; underlying disease and pretransplant dialysis (yes/no). Patient characteristics are described in Table 1.Table 1:Robotic kidney transplant and control patient characteristicsRobotic transplant (n = 28)Controls (n = 28)p-ValueDemographicsAge (years), mean (SD)47.9 (10.7)49.8 (10.8)0.51Gender (male), No. (%)13 (46.4)11 (39.3)0.59Race (African American/Hispanic/White), No. (%)13/10/5 (46.4/35.7/17.9)13/10/5 (46.4/35.7/17.9)ClinicalBMI (kg/m2), mean (SD)42.6 (7.8)38.1 (5.4)0.02Obese (30≤BMI< 35)/morbidly Obese (BMI≥35), No. (%)6/22 (21.4/78.6)6/22 (21.4/78.6)Creatinine pretransplant (mg/dl), mean (SD)7.6 (3.5)6.3 (2.5)0.11Dialysis, No. (%)19 (67.9)20 (71.4)0.77Duration on dialysis (months; n = 17/17), mean (SD)32.0 (34.7)15.6 (11.8)0.08Crossmatch positive, No. (%)7 (25.0)7 (25.0)ABO incompatible, No. (%)1 (3.6)1 (3.6)ComorbiditiesCAD, No. (%)9 (32.1)9 (32.1)CVD, No. (%)1 (3.6)4 (14.3)0.35PAV, No. (%)2 (7.1)4 (14.3)0.67Asthma/sleep apnea, No. (%)5 (17.9)3 (10.7)0.71Congestive heart failure, No. (%)2 (7.1)2 (7.1)Cause of kidney failureDiabetes, No. (%)7 (25.0)2 (7.1)0.14Hypertension, No. (%)8 (28.6)11 (39.3)0.40Diabetes + hypertension, No. (%)2 (7.1)10 (35.7)0.009FSGS, No. (%)2 (7.1)1 (3.6)0.99Graft failure/retransplant, No. (%)2 (7.1)00.49Lupus nephritis, No. (%)1 (3.6)00.99Obstructive uropathy, No. (%)1 (3.6)00.99Analgesic nephropathy, No. (%)1 (3.6)00.99Wegener’s granulomatosis, No. (%)1 (3.6)00.99Postinfectious crescentic glomerulonephritis, No. (%)1 (3.6)00.99Alport’s syndrome, No. (%)01 (3.6)0.99Hemolytic uremic syndrome, No. (%)01 (3.6)0.99Hypertension + nephrotic syndrome, No. (%)01 (3.6)0.99Unknown, No. (%)2 (7.1)1 (3.6)0.99BMI = body mass index; CAD = coronary artery disease; CVD = cerebrovascular disease; FSGS = focal segmental glomerulosclerosis; PAV = peripheral arterial disease; SD = standard deviation.To convert creatinine (mg/dL) to SI units (umol/L), multiply by 88.4. Open table in a new tab BMI = body mass index; CAD = coronary artery disease; CVD = cerebrovascular disease; FSGS = focal segmental glomerulosclerosis; PAV = peripheral arterial disease; SD = standard deviation. To convert creatinine (mg/dL) to SI units (umol/L), multiply by 88.4. The pretransplant workup for all patients regardless of surgical procedure followed Center of Medicare and Medicaid Services guidelines. Historically, our institution had never excluded any patient from transplantation based on body weight if the pretransplant workup did not show any formal contraindications. However, the average BMI of the control group was significantly lower than the robotic group, since we were not able to find equally obese patients in the control group. The immunological status of the recipient was not used to select patients. Kidney transplantation was offered to presensitized patients, patients undergoing desensitization in the presence of a positive cross-match or ABO incompatibility to their prospective living donors, as well as patients with a history of previous kidney transplantation. The institutional review board at the University of Illinois at Chicago approved this chart review (IRB Protocol 2011-1104). Robotic kidney transplants were performed as previously described (16Giulianotti P Gorodner V Sbrana F et al.Robotic transabdominal kidney transplantation in a morbidly obese patient.Am J Transplant. 2010; 10: 1478-1482Abstract Full Text Full Text PDF PubMed Scopus (129) Google Scholar). Hand-assisted clamping of the iliac artery and vein during the anastomosis, at least during the early case experiences, provided additional safety in the case of any vascular accident. However, with increasing experience, robotic vascular clamps for clamping the external iliac vessels were used. All patients were started intraoperatively on intravenous heparin infusion at a standard rate of 300 units/h and maintained on heparin until discharge. Living donations were performed robotically as previously described (17Gorodner V Horgan S Galvani C Manzelli A et al.Routine left robotic-assisted laparoscopic donor nephrectomy is safe and effective regardless of the presence of vascular anomalies.Transpl Intern. 2006; 19: 636-640Crossref PubMed Scopus (52) Google Scholar). Patients who were African American, retransplant, crossmatch positive and/or ABO-incompatible underwent the high-risk protocol consisting of induction with rabbit antithymocyte globulin (ATG), and maintenance immunosuppression by a combination of tacrolimus, mycophenolate mofetil (MMF) and a rapid steroid taper completed by postoperative day (POD) 6. In addition, positive crossmatch and ABO-incompatible patients underwent a desensitization protocol with plasmapheresis (PP) and intravenous immunoglobulins (IVIg) as previously described (18Thielke JJ West-Thielke PM Herren HL et al.Living donor kidney transplantation across positive crossmatch: The University of Illinois at Chicago experience.Transplantation. 2009; 87: 268-273Crossref PubMed Scopus (91) Google Scholar). In positive crossmatch patients, steroids were tapered rapidly to the dose of 10 mg of prednisone by POD 5 and maintained at that dose thereafter. ABO-incompatible recipients underwent laparoscopic spleenectomy during the same procedure as previously described (19Grim SA Pham T Thielke J et al.Infectious complications associated with the use of rituximab for ABO-incompatible and positive cross-match renal transplant recipients.Clin Transplant. 2007; 21: 628-632Crossref PubMed Scopus (75) Google Scholar). Transplant recipients who were Hispanic or non-Hispanic white and negative cross-match underwent the low-risk protocol consisting of induction with 20 mg Basiliximab, with the first dose given at the induction of anesthesia and the second on POD 4. Maintenance immunosuppression included a combination of tacrolimus and MMF, and a rapid steroid taper completed by POD 6. The established criteria by the Center for Disease Control and Prevention were used to define SSI. This includes a surgeon diagnosis of infection, a positive fluid culture from the wound and purulent exudate drainage from the surgical site. The wounds were classified as incisional superficial or incisional deep according to the soft tissue involvement (20Horan TC Gaynes RP Martone WJ Jarvis WR Emori TG CDC definitions of nosocomial surgical site infectionsa modification of CDC definitions of surgical wound infections.Infect Control Hosp Epidemiol. 1992; 13: 606-608Crossref PubMed Google Scholar). Means and frequencies were used to describe the patient characteristics. Medical costs were adjusted to 2011 prices (21CPI Inflation Calculator. Bureau of Labor Statistics. United States Department of Labor. Visited October 2012. http://www.bls.gov/data/inflation_calculator.htmGoogle Scholar). As the robotic group (n = 28) and control group (n = 28) were frequency matched (not pair matched), comparisons between the groups were performed using the chi-square test for categorical variables, with Yates’ correction or Fisher’s exact test when appropriate, and the unpaired t-test for continuous variables. The primary outcomes of interest were wound complications and SSIs. Tests were two tailed and statistical significance was set at p < 0.05. Statistical analysis was performed by IBM SPSS 19.0 (Armonk, NY, USA) and SAS version 9.2 (Cary, NC, USA). The majority of the patients were African American (46.4%) or Hispanic (35.7%), with a mean age of 47.9 ± 10.7 and 49.8 ± 10.8 years for the robotic and control group, respectively (p = 0.51). The control group had a significantly lower average BMI than the robotic transplant group (38.1 ± 5.4 kg/m2 vs. 42.6 ± 7.8 kg/m2, respectively; p = 0.02), but the proportion of patients who were obese/morbidly obese was comparable between the two groups. The leading causes of kidney failure were hypertension, diabetes, or the combination in the robotic (60.7%) and control group (82.1%). Two of the 28 patients in both groups underwent deceased donor kidney transplantation; the remaining patients had a suitable living donor. The presence of donor vascular anomalies required a vascular reconstruction during the graft bench preparation for two (7.1%) and five (23.8%) patients in the robotic and control group (p = 0.12), respectively. There were no significant differences in mean cold and warm ischemia times (robotic group: 2.8 and 47.7 min; controls: 2.0 and 49.2 min; p ≥ 0.48). Only one control patient required an intraoperative blood transfusion. The majority of patients in both groups received induction and maintenance therapy with thymoglobulin (n = 21, 75%) and tacrolimus (n = 23, 82.1%).Table 2:Robotic kidney transplant and control patient intraoperative outcomesRobotic transplant (n = 28)Controls (n = 28)p-ValueSurgeryCold ischemia time (hours; n = 28/18), mean (SD)2.8 (3.6)2.0 (4.5)0.48Warm ischemia time (minutes; n = 28/19), mean (SD)47.7 (7.8)49.2 (25.2)0.77Blood loss (mls; n = 27/20), mean (SD)110.2 (75.2)120.8 (102.4)0.69Intraoperative blood transfusion, No. (%)01 (3.6)0.99Intraoperative vascular complication, No. (%)02 (7.1)0.49Induction: Thymoglobulin/basiliximab/daclizumab, No. (%)21/7/0 (75.0/25.0/0)21/2/5 (75.0/7.1/17.9)0.02Maintenance: Tacrolimus/neoral/sirolimus/ tacrolimus+sirolimus/tacrolimus+MMF, No. (%)23/3/0/0/2 (82.1/10.7/0/0/7.1)23/3/1/1/0 (82.1/10.7/3.6/3.6/0)0.41DonorLiving donor, No. (%)26 (92.9)26 (92.9)Related donor (n = 26/26), No. (%)20 (76.9)17 (65.4)0.36Robotic donor nephrectomy (n = 26/26), No. (%)26 (100)26 (100)Age (years; n = 27/26), mean (SD)32.3 (10.1)34.3 (11.8)0.52Gender (male; n = 28/26), No. (%)16 (57.1)9 (34.6)0.10BMI (kg/m2; n = 20/26), mean (SD)29.4 (7.1)30.7 (5.9)0.52Vascular anomalies (n = 28/21), No. (%)2 (7.1)5 (23.8)0.12BMI = body mass index; MMF = mycophenolate mofetil; SD = standard deviation. Open table in a new tab BMI = body mass index; MMF = mycophenolate mofetil; SD = standard deviation. In the robotic group, one patient required hemodialysis within the first week after transplantation (delayed graft function). Seven patients (25%) in the robotic group underwent kidney biopsy for rejection suspicion as indicated by decreased urine output and an elevation in serum creatinine > 25% in the absence of other causes. Considering the intraperitoneal location of the graft in robotic recipients, the kidney biopsies were performed laparoscopically. In one case, the renal allograft was covered by adhesive bands and an open procedure via a small McBurney incision for the biopsy was considered safer. Rejection occurred in seven (25%) and five (17.9%) patients in the robotic and control group, respectively. Acute cellular rejection (ACR) was confirmed in four patients in the robotic group (Banff score 2A [n = 1] or 1B [n = 3]) and three controls (Banff score 1A [n = 1] or undetermined [n = 2]) (22Solez K Colvin RB Racusen LC Sis B Halloran PF Birk PE et al.Banff ‘05 meeting report: Differential diagnosis of chronic allograft injury and elimination of chronic allograft nephropathy (‘CAN’).Am J Transplant. 2007; 7: 518-526Crossref PubMed Scopus (934) Google Scholar). All the patients were treated with a good response. Antibody-mediated rejection (AMR) was confirmed in four robotic patients, including one mixed form and confirmed in two controls.Table 3:Robotic kidney transplant and control patient 6-month outcomesRobotic transplant (n = 28)Controls (n = 28)p-ValueSurgical outcomesDelayed graft function, No. (%)1 (3.6)00.99Surgical biopsy*Surgical biopsies were performed by the laparoscopic technique and one was converted to open procedure by a mini McBurney incision directly over the graft. ACR = acute cellular rejection; AMR = antibody-mediated rejection; CMV = cytomegalovirus;. To convert creatinine (mg/dL) to SI units (umol/L), multiply by 88.4., No. (%)7 (25.0)00.01Wound complications, No. (%)1 (3.6)8 (28.6)0.02Wound infections, No. (%)08 (28.6)0.004Creatinine at discharge (mg/dL), mean (SD)2.0 (1.4)1.4 (0.5)0.04Creatinine at 6 months (mg/dL), mean (SD)1.5 (0.4)1.6 (0.6)0.47Graft survival at 6 months, No. (%)28 (100)28 (100)Patient survival at 6 months, No. (%)28 (100)28 (100)Resource utilizationHospital days for transplant, mean (SD)8.2 (4.5)8.1 (5.3)0.98Total hospital days over 6 months, mean (SD)14.3 (10.2)15.8 (17.3)0.69Readmission over 6 months, mean (SD)1.6 (2.0)1.5 (1.5)0.82Reoperation over 6 months, No. (%)01 (3.6)0.99Hospital costs for transplant ($; n = 28/25), mean (SD)75,14860,5520.02Total hospital costs over 6 months ($), mean (SD)86,27266,4870.04Total follow-up (months), mean (SD)12.0 (6.0)35.7 (17.2) 40 kg/m2) (8Lynch RJ Ranney DN Shijie C Lee DS Samala N Englesbe MJ Obesity, surgical site infection, and outcome following renal transplantation.Ann Surg. 2009; 250: 1014-1020Crossref PubMed Scopus (190) Google Scholar,23Marks WH Florence LS Chapman PH Precht AF Perkinson DT Morbid obesity is not a contraindication to kidney transplantation.Am J Surg. 2004; 187: 635-638Abstract Full Text Full Text PDF PubMed Scopus (88) Google Scholar). The higher incidence of wound complications in obese patients has been proposed to be related to greater dead space above the fascia, longer operative times, need for a larger incision and a higher prevalence of diabetes. In our robotic series, 16 of 28 (57.1%) recipients had a BMI > 40 and 32.1% had diabetes prior to transplant. Results of our robotic group are therefore comforting in terms of wound complications and SSI occurrence. However, we did encounter one noninfectious wound complication presenting in the form of a subcutaneous hematoma with subsequent superficial wound dehiscence secondary to Coumadin treatment. Our hypothesis that minimally invasive, robotic kidney transplantation would reduce the risk of wound infections was therefore confirmed. Overall we attribute the achievement of significantly fewer SSIs to replacing the large suprainguinal incision in a highly colonized area, necessary to access the external iliac vessels in open kidney transplantation, with a 7 cm periumbilical incision for insertion of the kidney graft. Obesity is also related to general postsurgical complications (24Patel S Cassuto J Orloff M et al.Minimizing morbidity of organ donation: analysis of factors for perioperative complications after living-donor nephrectomy in the United States.Transplantation. 2008; 85: 561-565Crossref PubMed Scopus (58) Google Scholar). Gore et al. (25Gore JL Pham PT Danovitch GM et al.Obesity and outcome following renal transplantation.Am J Transplant. 2006; 6: 357-363Crossref PubMed Scopus (289) Google Scholar) found that BMI impacts early and long-term transplant outcomes by increasing the days of hospitalization and the incidence of delayed graft function. In our case series, there was only one patient with delayed graft function in the robotic group, and the minimally invasive approach allowed for early mobilization and rehabilitation of these otherwise rather immobile obese patients. Three recipients in the robotic group had a prolonged hospitalization (over 14 days), compared with four patients in the control group. Readmissions and reoperation rate were also similar between the two groups. Notable issues that occurred in the other 11 patients not included in the current analysis due to less than six months of follow-up included one death from fulminant line sepsis on POD 9, after a complication-free surgery and immediate graft function. Another patient with a BMI of 54.5 kg/m2 developed a median incisional hernia 1.5 months after transplantation and required an abdominoplastic hernia repair. Two of the 39 patients (5.1%) initially started robotically were converted to the standard open procedure. In both cases, conversion to open surgery was indicated by the presence of severe adhesions. One of them developed a wound hematoma that needed drainage and wound healing by secondary intention. Beyond any doubt, this is a very morbid patient population, and the surgery and posttransplant follow-up can be complicated. There is substantial evidence that obesity is a risk factor for rejection. The analysis performed by Gore et al. (25Gore JL Pham PT Danovitch GM et al.Obesity and outcome following renal transplantation.Am J Transplant. 2006; 6: 357-363Crossref PubMed Scopus (289) Google Scholar) found a significant independent association of morbid obesity with increased acute rejection, and decreased overall graft survival. In our series of 28 robotic and control patients, we observed seven cases of biopsy-proven rejection (25%) in the robotic group: three ACR, three AMR and one mixed ACR+AMR; compared with five cases biopsy-proven rejection (17.9%) in the control group: three ACR and two AMR. No patient or graft was lost in either the robotic or control groups during follow-up. There are some issues to consider with regard to the new robotic technology for kidney transplant. First, we observed a significantly lower serum creatinine at discharge in the controls than in the robotic surgery group. The average warm ischemia time was longer in the current analysis of obese patients compared to the average for nonobese patients at our center (30–35 min). However, mean warm ischemia time was comparable between the robotic (47.7 min) and open (49.2 min) techniques and prolonged time likely does not explain the higher discharge creatinine in the robotic group. Therefore, we have to consider a possible influence of prolonged pneumoperitoneum on the early graft function, as previously suggested (26London 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: 195-201Crossref PubMed Scopus (172) Google Scholar). However, at 6 months postrobotic transplantation, kidney function was not different from the open group. Second, the Achilles heel of robotic kidney transplantation is the intraperitoneal location of the graft, which in conjunction with the obesity of patients, potentially increases the risk for complications related to standard ultrasonography-guided percutaneous kidney graft biopsy. For this case series, we chose to perform kidney graft biopsies by laparoscopy, though with increased experience, in the future, many of these patients may undergo percutaneous kidney graft biopsy. This greater barrier to kidney graft biopsy could lead to increased treatment on a presumptive basis, therefore biasing these patients toward better or worse acute rejection outcomes depending on the data considered for the analysis, biopsy reports or treatments for rejection. Third, the increased technical complexities of the procedure will also likely limit the initial implementation of the new surgical procedure to select academic centers. However, these centers are often located in highly urban areas with larger minority populations who could benefit from the procedure. After our initial experience standardizing the procedure and eliminating logistical limitations with extensive training of the staff and surgeons, the robotic procedure is now available in our center at all times for both living and deceased donors. The primary technical restriction to performing the robotic surgery is extensive peripheral vascular disease in the recipient and significant atherosclerosis in the graft vessels with a deceased donor. Fourth, the medical costs were significantly higher for the robotic surgical technique compared to the open technique. As hospital days and outcomes were comparable, if not better in terms of SSIs, for the robotic group and controls, the higher costs are a function of the robotic surgical system. However, the higher costs will have to be balanced against the cost of keeping obese renal failure patients on dialysis. The current analysis has some weaknesses. The mean follow-up for the robotic surgery group is 1 year. However, there is extensive evidence in the literature that 6-month creatinine is predictive of long-term graft survival (27First MR Renal function as a predictor of long-term graft survival in renal transplant patients.Nephrol Dial Transplant. 2003; 18: i3-i6Crossref PubMed Google Scholar). The control group was also not concurrent to the robotic surgery group. This resulted in a higher BMI in the robotic group compared to controls, as the robotic procedure was performed more recently and was offered to all obese patients after training and standardization allowing more obese patients with ESRD to be transplanted. However, the same group of surgeons and staff were involved in all of the surgeries presented in both groups, with similar protocols for antibiotic and aseptic management in the operating room and immunosuppressive therapy and patient management after transplant. The incidence of complications in either group did not vary over time indicating the lower incidence of SSIs in the robotic group is likely not due to greater experience over time. The study was not a randomized controlled trial because such a design would be impractical based on the unwillingness of patients to be assigned to a open technique control group after features of both procedures were explained, considering the shorter recovery time and cosmetic appearance with the robotic technique. Further, the inability to blind patients and providers to treatment group would limit comparisons. From a public health perspective, the question could be raised whether patients should lose weight before undergoing transplantation. The low success rate of medical weight loss has been extensively discussed in the medical literature (28Wu T Gao X Chen M vanDan RM Long-term effectiveness of diet-plus-exercise interventions vs. diet-only interventions for weight loss: A meta-analysis.Obes Rev. 2009; 10: 313-323Crossref PubMed Scopus (367) Google Scholar); and randomized trials of bariatric surgery indicate that 12 months following the procedure, approximately 30–65% of excess weight remains (29Franco JVA Ruiz PA Palermo M Gagner M A review of studies comparing three laparoscopic procedures in bariatric surgery: Sleeve gastrectomy, roux-en-y gastric bypass and adjustable gastric banding.Obes Surg. 2011; 21: 1458-1468Crossref PubMed Scopus (159) Google Scholar). Considering the significant 6-month (5–10%), 1-year (10–17%) and 2-year (18–29%) mortality on dialysis for patients age 20–64 years (1U.S. Renal Data System. USRDS 2011Annual Data Report: Atlas of Chronic Kidney Disease and End-Stage Renal Disease in the United States.. National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD2011Google Scholar), it is evident that these patients face a battle against the clock and simply may not have enough time left to normalize their body weight before kidney transplantation. Pursuing weight loss would increase the pretransplant mortality for patients presenting with a living donor. In the case of deceased donor donation, pretransplant weight loss for newly listed patients or patients with little wait time may make sense, and is the strategy at our center and many others. Therefore, with the majority of our patients presenting with a living donor, we chose an approach that would first offer the kidney transplant, and subsequently guide our patients through weight loss and hypertension and diabetes management. In light of evidence that obese patients with no SSIs had the same kidney transplant success rate as patients with a normal BMI (8Lynch RJ Ranney DN Shijie C Lee DS Samala N Englesbe MJ Obesity, surgical site infection, and outcome following renal transplantation.Ann Surg. 2009; 250: 1014-1020Crossref PubMed Scopus (190) Google Scholar), weight loss and comorbidity management after robotic transplant may further improve outcomes. Ongoing follow-up is underway to determine long-term graft and patient survival. While in most instances the rationale for minimally invasive surgery is based on reduced postoperative discomfort and improved cosmetic appearance, robotic technology in this case allowed surgeons at our center to offer transplantation to a population that has been found to have a greater likelihood of being bypassed for kidney transplantation compared to nonobese patients (2). The robotic technique may also help to reduce health disparities due to ESRD in populations with a higher prevalence of obesity. Now that the robotic technique is consistently used for kidney transplant in obese patients at our center, future research can determine the impact robotic surgery may have on changing wait times, access to transplantation, comorbidities, quality of life and survival. There were no sources of funding. The results were previously presented orally (abstract 157) at the American Transplant Congress 2012. The authors of this manuscript have no conflicts of interest to disclose as described by the American Journal of Transplantation.