World J Urol DOI 10.1007/s00345-014-1312-7
Original Article
Transperitoneal versus retroperitoneal robotic partial nephrectomy: matched‑pair comparisons by nephrometry scores Seol Ho Choo · Seo Yeon Lee · Hyun Hwan Sung · Hwang Gyun Jeon · Byong Chang Jeong · Seong Soo Jeon · Hyun Moo Lee · Han Yong Choi · Seong Il Seo
Received: 25 March 2014 / Accepted: 28 April 2014 © Springer-Verlag Berlin Heidelberg 2014
Abstract Purpose The purpose of this study was to compare perioperative outcomes of transperitoneal (TP) and retroperitoneal (RP) robot-assisted partial nephrectomy (RPN) by matched analysis using nephrometry systems. Methods A total of 107 patients who underwent RPN by a single surgeon from December 2008 to June 2012 were analyzed; 57 patients underwent TP RPN and 50 patients underwent RP RPN. Baseline demographic characteristics, perioperative outcomes and changes in renal function were collected by retrospective review of medical records. Matched-pair comparisons were done using RENAL score and C-index. Results No significant difference was observed between TP and RP RPN in patient age, body mass index, gender, laterality, clinical stage, tumor size, RENAL score or ASA score. The TP RPN had more cystic renal masses (TP vs. RP = 33 vs. 12 %, p = 0.012) and RP RPN had shorter median operation times (150 vs. 120 min, p = 0.015) and shorter mean warm ischemic times (26.2 vs. 22.6 min, p = 0.040) than TP RPN. In the matched-pair analysis, RP RPN showed shorter operation times with similar warm S. H. Choo · H. H. Sung · H. G. Jeon · B. C. Jeong · S. S. Jeon · H. M. Lee · H. Y. Choi · S. I. Seo (*) Department of Urology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon‑ro, Gangnam‑gu, Seoul 135‑710, Korea e-mail: [email protected] S. H. Choo Department of Urology, Ajou University School of Medicine, Suwon, Korea S. Y. Lee Department of Urology, Myongji Hospital, Kwandong University College of Medicine, Goyang, Korea
ischemic times. Estimated blood loss and visual analog pain scales showed no significant differences between groups. A total of 12 (11.4 %) postoperative complications occurred, all Clavien class I or II with no significant difference in incidence. Conclusions Retroperitoneal robot-assisted partial nephrectomy showed shorter operation time and generally equivalent perioperative results to TP RPN. RP RPN is a viable treatment option for treating posterior or lateral renal masses. Keywords Robotics · Kidney neoplasm · Partial nephrectomy · Nephrometry score
Introduction Partial nephrectomy has become a standard treatment option for small renal masses. It has an excellent oncologic outcome with long-term preservation of renal function, leading to a high quality of life and overall survival [1, 2]. Demands for minimally invasive surgery resulted in the development of laparoscopic partial nephrectomy (LPN) with transperitoneal (TP) and retroperitoneal (RP) approaches. The TP approach provides larger working space, allows wider angles to reach tumors and gives better orientation via familiar anatomical landmarks than the RP approach [3–5]. However, TP approaches need to bowel mobilization, which might have chance of complications related to bowels. In patients with previous abdominal surgery, the TP approach is often difficult or not possible because of intraabdominal adhesions or scarring. The advantages of the RP approach to renal surgery are well established [6]. An important benefit is that the RP approach enables direct access to the renal artery
13
World J Urol
and does not require mobilization of organs around the kidney, minimizing the chance of internal organ injury. However, the RP approach is technically more difficult because of the smaller working space and limited distinct anatomical landmarks [5]. Robot-assisted partial nephrectomy (RPN) has advantages over LPN including three-dimensional visualization and increased dexterity. RPN overcomes the technical difficulties of LPN and is reported to have outcomes that are comparable or superior to LPN [7, 8]. However, most reported results are for TP RPN. Although Weizer et al. [9] recently described techniques and early outcomes of RP RPN, few reports have compared surgical outcomes for TP and RP RPN. We compared perioperative outcomes for TP and RP RPN performed by a single surgeon using matched analysis with nephrometry scores representing the location and character of the renal mass.
Materials and methods Patients Patients who underwent TP and RP RPN between December 2008 and June 2012 for renal mass suspected to be a neoplasm were identified. The single surgeon (Seo SI) performed all RPNs. Surgical approaches were determined by tumor location. Generally, the TP approach was selected for anterior masses and the RP approach was chosen for posterior and lateral masses. For our 131 RPN cases, the 20 initial cases were excluded to prevent the influence of a learning curve [10]. Another four cases were excluded for two conjoined operations and two multiple renal mass cases. Surgical technique The technique of retroperitoneal partial nephrectomy [11] and TP partial nephrectomy has been described previously [12, 13]. The trocar configuration for the each approach is illustrated in the Fig. 1. The margin and depth of the mass were evaluated with intraoperative ultrasound and marked the incision line with electrocautery. To reduce ischemic renal damage, 12.5 g mannitol was administered 10 min before tumor resection. Renal vessels were clamped with laparoscopic bulldog clamps by an assistant. Only renal arteries were clamped, but in some cases of centrally located or large tumors, renal veins were also clamped. Tumors were resected by cold scissors. The resection bed was continuously sutured by 3-0 monofilament absorbable thread with the aid of absorbable suture clip. Parenchymal suture was performed using a sliding clip technique [14].
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Fig. 1 Trocar configuration for robot-assisted partial nephrectomy. a retroperitoneal approach. b transperitoneal approach—fourth robotic arm (dotted circle) is used temporarily during the hilar dissection. A = 12 mm assistant port; C = 12 mm camera port; R = 8 mm robotic port; L = 5 mm port for liver retraction (In case of left side, a port for liver retraction is not necessary, the other port configurations are mirror image of right side)
Perioperative outcomes and nephrometry scores We reviewed medical records for patient age, sex, body mass index, American Society of Anesthesia physical status score (ASA score), tumor laterality and solidity. RENAL [15] and C-index [16] scores were calculated by reviewing preoperative contrast-enhanced computed tomography without information on patient clinical profiles. Operation time (measured as console time), warm ischemic time (WIT), estimated blood loss (EBL) and days to oral resumption were evaluated. Mean of three measured VAS in a day was used to investigate postoperative pain. Intraoperative and postoperative complications were evaluated and classified using the Clavien–Dindo classification [17]. Estimated glomerular filtration rate (GFR) was calculated to assess renal function using the abbreviated modification of diet in the renal disease equation (MDRD-GFR) [18]. Statistical analysis Student’s t test and the Mann–Whitney U test were used for continuous variables and the chi-square test was used
World J Urol
for categorical variables. Matched-pair analysis was performed comparing data for patients after TP RPN and RP RPN with 1:1 exact matching performed by an institutional statistician according to nephrometry system scores. For the RENAL system, the anterior/posterior item was not matched because it is a factor that influences the surgeon’s decision on the approach. Because C-index was a continuous variable, caliper matching was used instead of exact matching. The caliper was defined as 25 % of the standard deviation of the C-index. Student’s t test, paired t test or Wilcoxon-signed rank test were done for continuous variables, and chi-square test, McNemar’s test or Bhapkar’s test were done for categorical variables. VAS score was subjected to Bonferroni correction because it was checked several times. All statistical analyses were performed using R 2.15.0 (R Foundation for Statistical Computing, Vienna, Austria) or Statistical Package for the Social Sciences 18 (SPSS Inc., Chicago, IL) with p
Original Article
Transperitoneal versus retroperitoneal robotic partial nephrectomy: matched‑pair comparisons by nephrometry scores Seol Ho Choo · Seo Yeon Lee · Hyun Hwan Sung · Hwang Gyun Jeon · Byong Chang Jeong · Seong Soo Jeon · Hyun Moo Lee · Han Yong Choi · Seong Il Seo
Received: 25 March 2014 / Accepted: 28 April 2014 © Springer-Verlag Berlin Heidelberg 2014
Abstract Purpose The purpose of this study was to compare perioperative outcomes of transperitoneal (TP) and retroperitoneal (RP) robot-assisted partial nephrectomy (RPN) by matched analysis using nephrometry systems. Methods A total of 107 patients who underwent RPN by a single surgeon from December 2008 to June 2012 were analyzed; 57 patients underwent TP RPN and 50 patients underwent RP RPN. Baseline demographic characteristics, perioperative outcomes and changes in renal function were collected by retrospective review of medical records. Matched-pair comparisons were done using RENAL score and C-index. Results No significant difference was observed between TP and RP RPN in patient age, body mass index, gender, laterality, clinical stage, tumor size, RENAL score or ASA score. The TP RPN had more cystic renal masses (TP vs. RP = 33 vs. 12 %, p = 0.012) and RP RPN had shorter median operation times (150 vs. 120 min, p = 0.015) and shorter mean warm ischemic times (26.2 vs. 22.6 min, p = 0.040) than TP RPN. In the matched-pair analysis, RP RPN showed shorter operation times with similar warm S. H. Choo · H. H. Sung · H. G. Jeon · B. C. Jeong · S. S. Jeon · H. M. Lee · H. Y. Choi · S. I. Seo (*) Department of Urology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon‑ro, Gangnam‑gu, Seoul 135‑710, Korea e-mail: [email protected] S. H. Choo Department of Urology, Ajou University School of Medicine, Suwon, Korea S. Y. Lee Department of Urology, Myongji Hospital, Kwandong University College of Medicine, Goyang, Korea
ischemic times. Estimated blood loss and visual analog pain scales showed no significant differences between groups. A total of 12 (11.4 %) postoperative complications occurred, all Clavien class I or II with no significant difference in incidence. Conclusions Retroperitoneal robot-assisted partial nephrectomy showed shorter operation time and generally equivalent perioperative results to TP RPN. RP RPN is a viable treatment option for treating posterior or lateral renal masses. Keywords Robotics · Kidney neoplasm · Partial nephrectomy · Nephrometry score
Introduction Partial nephrectomy has become a standard treatment option for small renal masses. It has an excellent oncologic outcome with long-term preservation of renal function, leading to a high quality of life and overall survival [1, 2]. Demands for minimally invasive surgery resulted in the development of laparoscopic partial nephrectomy (LPN) with transperitoneal (TP) and retroperitoneal (RP) approaches. The TP approach provides larger working space, allows wider angles to reach tumors and gives better orientation via familiar anatomical landmarks than the RP approach [3–5]. However, TP approaches need to bowel mobilization, which might have chance of complications related to bowels. In patients with previous abdominal surgery, the TP approach is often difficult or not possible because of intraabdominal adhesions or scarring. The advantages of the RP approach to renal surgery are well established [6]. An important benefit is that the RP approach enables direct access to the renal artery
13
World J Urol
and does not require mobilization of organs around the kidney, minimizing the chance of internal organ injury. However, the RP approach is technically more difficult because of the smaller working space and limited distinct anatomical landmarks [5]. Robot-assisted partial nephrectomy (RPN) has advantages over LPN including three-dimensional visualization and increased dexterity. RPN overcomes the technical difficulties of LPN and is reported to have outcomes that are comparable or superior to LPN [7, 8]. However, most reported results are for TP RPN. Although Weizer et al. [9] recently described techniques and early outcomes of RP RPN, few reports have compared surgical outcomes for TP and RP RPN. We compared perioperative outcomes for TP and RP RPN performed by a single surgeon using matched analysis with nephrometry scores representing the location and character of the renal mass.
Materials and methods Patients Patients who underwent TP and RP RPN between December 2008 and June 2012 for renal mass suspected to be a neoplasm were identified. The single surgeon (Seo SI) performed all RPNs. Surgical approaches were determined by tumor location. Generally, the TP approach was selected for anterior masses and the RP approach was chosen for posterior and lateral masses. For our 131 RPN cases, the 20 initial cases were excluded to prevent the influence of a learning curve [10]. Another four cases were excluded for two conjoined operations and two multiple renal mass cases. Surgical technique The technique of retroperitoneal partial nephrectomy [11] and TP partial nephrectomy has been described previously [12, 13]. The trocar configuration for the each approach is illustrated in the Fig. 1. The margin and depth of the mass were evaluated with intraoperative ultrasound and marked the incision line with electrocautery. To reduce ischemic renal damage, 12.5 g mannitol was administered 10 min before tumor resection. Renal vessels were clamped with laparoscopic bulldog clamps by an assistant. Only renal arteries were clamped, but in some cases of centrally located or large tumors, renal veins were also clamped. Tumors were resected by cold scissors. The resection bed was continuously sutured by 3-0 monofilament absorbable thread with the aid of absorbable suture clip. Parenchymal suture was performed using a sliding clip technique [14].
13
Fig. 1 Trocar configuration for robot-assisted partial nephrectomy. a retroperitoneal approach. b transperitoneal approach—fourth robotic arm (dotted circle) is used temporarily during the hilar dissection. A = 12 mm assistant port; C = 12 mm camera port; R = 8 mm robotic port; L = 5 mm port for liver retraction (In case of left side, a port for liver retraction is not necessary, the other port configurations are mirror image of right side)
Perioperative outcomes and nephrometry scores We reviewed medical records for patient age, sex, body mass index, American Society of Anesthesia physical status score (ASA score), tumor laterality and solidity. RENAL [15] and C-index [16] scores were calculated by reviewing preoperative contrast-enhanced computed tomography without information on patient clinical profiles. Operation time (measured as console time), warm ischemic time (WIT), estimated blood loss (EBL) and days to oral resumption were evaluated. Mean of three measured VAS in a day was used to investigate postoperative pain. Intraoperative and postoperative complications were evaluated and classified using the Clavien–Dindo classification [17]. Estimated glomerular filtration rate (GFR) was calculated to assess renal function using the abbreviated modification of diet in the renal disease equation (MDRD-GFR) [18]. Statistical analysis Student’s t test and the Mann–Whitney U test were used for continuous variables and the chi-square test was used
World J Urol
for categorical variables. Matched-pair analysis was performed comparing data for patients after TP RPN and RP RPN with 1:1 exact matching performed by an institutional statistician according to nephrometry system scores. For the RENAL system, the anterior/posterior item was not matched because it is a factor that influences the surgeon’s decision on the approach. Because C-index was a continuous variable, caliper matching was used instead of exact matching. The caliper was defined as 25 % of the standard deviation of the C-index. Student’s t test, paired t test or Wilcoxon-signed rank test were done for continuous variables, and chi-square test, McNemar’s test or Bhapkar’s test were done for categorical variables. VAS score was subjected to Bonferroni correction because it was checked several times. All statistical analyses were performed using R 2.15.0 (R Foundation for Statistical Computing, Vienna, Austria) or Statistical Package for the Social Sciences 18 (SPSS Inc., Chicago, IL) with p
