Comparison of Trifecta Outcome Among Open, Laparoscopic, and Robotic-Assisted Partial Nephrectomy in Patients With Small Renal Masses: 10-Year Experience in Ramathibodi Hospital

Purpose: To compare the trifecta outcome and perioperative and postoperative outcomes among open partial nephrectomy (OPN), laparoscopic partial nephrectomy (LPN), and robotic-assisted partial nephrectomy (RAPN) in patients with small renal masses in Ramathibodi Hospital. Methods: We retrospectively reviewed 141 patients who underwent partial nephrectomy from January 2009 to December 2018. The baseline characteristics and preoperative outcomes were compared among the three surgical approaches. Results: Among the 141 patients, 42 (29.79%), 29 (20.57%), and 70 (49.64%) patients underwent OPN, LPN, and RAPN, respectively. Among 116 patients with available data, 71 achieved the trifecta outcome [18 (56.25%), 14 (56.00%), and 39 (73.58%) in the OPN, LPN, and RAPN group, respectively; p=0.276]. The rate of conversion to OPN was higher in the LPN than RAPN group. The number of patients who received intraoperative packed red cells was lowest in the RAPN group. The estimated blood loss was signicantly lower in the LPN group than OPN and RAPN groups (p=0.041). The operative time was shorter in the OPN group than LPN and RAPN groups (p<0.001). Multivariate analysis showed that the intraoperative complication rate was a predictive factor for trifecta outcome achievement. Conclusion: OPN had the shortest operative time. LPN had the highest rate of conversion to OPN and lowest estimated blood loss. The number of patients who received intraoperative packed red cells was lowest in the RAPN group. However, achievement of the trifecta outcome was not signicantly different among the three groups. The predictive factor for trifecta outcome achievement was the intraoperative complication rate.


Introduction
Perioperative and postoperative data were also collected, including the operative time (skin incision to skin closure time), estimated blood loss (EBL), blood transfusion, warm ischemia time, cold ischemia time, length of hospital stay (LOS), 1-year postoperative creatinine concentration and eGFR, and perioperative and postoperative complications. Trifecta outcome achievement was de ned as the combination of negative surgical margins, no severe complications (Clavien-Dindo grade 0-2), and a postoperative eGFR of > 90% of the preoperative eGFR. All methods were carried out in accordance with relevant guidelines and regulations Statistical analysis Predictive factors for trifecta outcome achievement were compared between patients who did and did not achieve the trifecta outcome using Student's t-test or the Mann-Whitney test for continuous variables and the chi-square test or Fisher's exact test for categorical variables. The patients' characteristics, perioperative and postoperative outcomes, and trifecta outcome achievement were compared among the three operative techniques using one-way analysis of variance or the Kruskal-Wallis test for continuous variables and the chi-square test for categorical variables. Univariate and multivariate analyses were performed using a logistic regression model to identify predictive factors associated with CKD, a risk of severe complications, and trifecta outcome achievement. All statistical analyses were performed with Stata v.14 (StataCorp, College Station, TX, USA). Statistical signi cance was de ned as a p-value of < 0.05.

Results
Among the 141 patients in this study, 42 (29.79%) underwent OPN, 29 (20.57%) underwent LPN, and 70 (49.64%) underwent RAPN ( Table 1). The patients' characteristics were similar among the three groups in terms of sex, age, body mass index, underlying disease, previous abdominal surgery, American Society of Anesthesiologists classi cation, and tumor size on imaging. Tumor complexity according to the RENAL nephrometry score was signi cantly greater in the RAPN than OPN and LPN groups (p = 0.005).  OPN, open partial nephrectomy; LPN, laparoscopic partial nephrectomy; RAPN, robot-assisted partial nephrectomy; RN, radical nephrectomy; PRC, packed red cells; eGFR; estimated glomerular ltration rate.
The pathologic data in the OPN, LPN, and RAPN groups were similar in terms of the tumor size, negative margin rate, and rate of RCC, with no signi cant differences as shown in Table 3. OPN, open partial nephrectomy; LPN, laparoscopic partial nephrectomy; RAPN, robot-assisted partial nephrectomy; eGFR, estimated glomerular ltration rate.
With respect to intraoperative complications, the incidence of collecting system perforation and severe complications (Clavien-Dindo grade 3-6) were similar among the three groups. The proportions of patients who achieved ≥ 90% preservation of the eGFR at 1 year postoperatively were also similar among the three groups, as shown in Table 4. OPN, open partial nephrectomy; LPN, laparoscopic partial nephrectomy; RAPN, robot-assisted partial nephrectomy; eGFR, estimated glomerular ltration rate Because of incomplete data in 25 patients, 116 patients were included in the trifecta outcome analysis. The proportion of patients who achieved the trifecta outcome was similar among the three groups, as shown in Table 5. In the univariate analysis, the factors that affected the trifecta outcome were male sex, LOS, rate of intraoperative complications, and rate of postoperative complications. In the multivariate analysis, the factors that affected the trifecta outcome were the LOS and rate of intraoperative complications, as shown in Table 6.

Discussion
Partial nephrectomy is an appropriate operation for the treatment of renal masses. In the past, OPN was the standard technique. LPN was later developed and is now increasing in use. In Ramathibodi Hospital, RAPN was rst performed in 2015. According to the 2017 American Urological Association guideline [8] and the 12th edition of Campbell Walsh Wein Urology [2], partial nephrectomy is recommended for patients with a cT1a renal mass, solitary kidney, bilateral renal tumors, familial RCC, and CKD or proteinuria as well as young patients with multifocal masses or comorbidities that may impact renal function in the future. The most common complications after partial nephrectomy are urine leakage, postoperative bleeding, urinary tract infection, arteriovenous malformations, pseudoaneurysms, and renal abscesses [11].
In the present study, the three groups had similar baseline patient and tumor characteristics except for the RENAL nephrometry score, which was highest in the RAPN group (p = 0.005). The EBL was highest in the OPN group ( The number of patients with ≥ 90% preservation of the eGFR at the 1-year follow-up was not signi cantly different among the three groups. The proportion of patients (n = 116) who achieved the trifecta outcome was also similar among the groups (p = 0.736). In the multivariate analysis, the factors that affected the trifecta outcome were the LOS and rate of intraoperative complications.
Three patients were readmitted. One patient was given intravenous antibiotics to treat an infected intraabdominal collection after RAPN, one underwent angiography and embolization of a renal AVF after RAPN, and one underwent angiography and embolization of a renal AVF after OPN.
As in our study, Mehra et al. [16] found that blood loss was lowest in the RAPN group (OPN > LPN > RAPN, p = 0.042). This can be explained by better visualization of the anatomy and movement control of instruments in RAPN. Similarly, Khalifeh et al. [17] concluded that the rate of a positive surgical margin was lower in RAPN than LPN. This may be due to technical di culty when performing LPN, especially when the mass is in the upper pole or a posterior location.
Both Zargar et al. [18] and Xia et al. [19] reported that the rate of intraoperative complications was similar in OPN and RAPN. According to Khalifeh et al. [17] and Porpiglia et al. [13], the rate of postoperative complications was lower in RAPN than in LPN and OPN.
As in our study, Zargar et al. [20] found that the postoperative creatinine concentration and eGFR were not different between LPN and RAPN. Yerram et al. [15] found that the proportion of patients with ≥ 90% eGFR preservation at follow-up was not different between OPN and RAPN.
As in our study, Yerram et al. [15] found that achievement of the trifecta outcome (de ned as negative surgical margins, no urologic complications, and ≥ 90% eGFR preservation at last follow-up) was not different between OPN and RAPN. This may be explained by the fact that LPN is inferior to both surgical OPN and RAPN because of its more challenging surgical techniques.
Zargar et al. [20] compared 646 LPN with 1185 RAPN procedures and de ned the trifecta outcome as negative surgical margins, no perioperative complications, and a warm ischemia time of ≤ 25 min. They found that the factors predicting achievement of the trifecta outcome were the type of surgery (RAPN), tumor size, EBL, and operative time.
As in our study, Mehra et al. [16] found that the operative time was not different among the three groups.
In contrast, however, Khalifeh et al. [17] found that the operative time was shorter for RAPN than LPN.
This can be explained by the steep learning curve of RAPN and the greater complexity of renal masses (higher RENAL scores) in the RAPN group in our study.
In contrast to our study, Han et al. [21] and Kim et al. [22] concluded that the LOS was signi cantly shorter for RAPN than OPN. LOS can be affected by many factors, including patient pain control, patient preference, socioeconomic status, and our institute practice.
Khalifeh et al. [17] and Porpiglia et al. [13] concluded that the rate of postoperative complications was lower in RAPN than LPN and OPN. However, we found no statistically signi cant difference in postoperative complications among our three groups.
Our study has three main limitations. First, it was a retrospective study with a small sample size. Second, the surgeries were performed by eight surgeons, which may have resulted in different outcomes. Third, performance of the eGFR evaluation at 1 year may have been too early to determine the actual long-term renal function outcomes.

Conclusion
There was no statistically signi cant difference in trifecta outcome achievement among patients who underwent OPN, LPN, and RAPN. LPN and RAPN were associated with lower EBL, a lower transfusion rate, and comparable pathologic outcomes in comparison with OPN. Therefore, both LPN and RAPN are feasible and safe techniques for the treatment of small renal masses. Moreover, LPN and RAPN may be utilized for the treatment of large renal masses in the future.