Our Results of Laparoscopic Partial Nephrectomies Without Pedicle Dissection: Possible Advantages and Disadvantages Ayhan Verit1, Ahmet Urkmez2*, Ozgur Haki Yuksel1, Fatih Uruc1 Purpose: This study aimed to document the surgical and oncologic results of nephron sparing of non-ischemic laparoscopic partial nephrectomy without the step of hilus controlling and even without dissecting to expose the main renal vascularity and directly focusing on mass removal. Materials & Methods: The records of the patients who underwent our modified laparoscopic partial nephrectomy technique were evaluated retrospectively. The patients’ medical records, including tumor complexity calculated via R.E.N.A.L nephrometry scores, operation time, estimated blood loss, blood transfusions, hospital stay, pre- and postoperative serum creatinine levels, complications via the Clavien classification system, pathological status of surgical margin, and follow-up times, were documented. Result: The data of 55 patients with 58 renal units were evaluated. Almost all tumors were in the low complex group (91%), with a mean size of 31.74 ± 7.38 mm (range: 12-46 mm). Mean operation time, estimated blood loss, and transfusion rates were 138.62 ± 38.45 minutes (range: 90-240 min), 242.24 ± 107.12 mL (range: 100-500 mL), and 19%, respectively. The hemoglobin level decreased by a mean of 2.05 ± 0.87 g/dL. Whereas the perioperative complications were Clavien grades I, II, and III (74%, 23%, and 3%, respectively), mean hospital stay and fol- low-up time were 4.05 ± 1.97 and 19.67 ± 13.57 (ranges: 2-10 days and 1-44 months), respectively. Conclusion: Present un-controlled results pointed that tumor-focusing nephron-sparing non-ischemic partial lap- aroscopic nephrectomy may be preferable for small-sized, low-complex renal masses. Keywords: laparoscopic partial nephrectomy; renal hilus dissection; tumor-focusing laparoscopy; zero ischemia INTRODUCTION The term “renal incidentaloma” was generally used to define small renal masses that were reported incidentally due to the widespread use of high techno- logic diagnostic instruments for nonspecific abdominal symptoms.(1) Since the advances in urological surgical techniques, laparoscopic partial nephrectomy (LPN) and robotic-assisted LPN are now the common pro- cedures, instead of open surgery, for the treatment of small renal masses, meaning the clinical T1a (< 4 cm) tumors.(2-5) In the classical surgical description, after the standard steps of renal laparoscopic approaches and dissections, hilar control was maintained and the main vessels that carrying one-fifth of the cardiac output were prepared for possible ischemic occlusion or sub- sequent nephrectomy.(5) Intraoperative ultrasonography can be used to confirm the location, width, and depth of the tumor after this step.(6) The main goals of LPN are to complete tumor excision without positive margins, obtain hemostasis, and decrease or even eliminate the warm ischemia time. Since every minute of ischemia is regarded as precious time to save renal function, the term of “zero ischemia” became popular for endoscopic 1University of Health Sciences, Fatih Sultan Mehmet Hospital, Dept. of Urology, Istanbul, Turkey. 2University of Health Sciences, Haydarpasa Numune Hospital, Dept. of Urology, Istanbul, Turkey. *Correspondence: Istanbul Haydarpasa Numune Hospital SAUM, Dept. of Urology, Uskudar Tr- 34668 Istanbul, Turkey. E mail: Ahmet Urkmez 0.05). The patients’ med- ical data related to the operation, such as tumor size, operation time (OT), estimatedf blood loss (EBL), hos- pital stay, and follow-up times are noted in Table 1. Any perioperative complications resulting from lapa- roscopic surgery were reported. The hemoglobin (Hb) level decreased by a mean of 2.05 ± 0.87 g/dL (range: 1-4.5 g/dL). Moreover, the postoperative period was uneventful without major complications. However, due to continued postoperative bloody effusion through the surgical region drainage system and decrease of Hb level to below 10 g/dL, 11 patients required one to three units of blood via transfusion. Enucleation of the mass was possible in eighteen (31%) of all sessions. All Laparoscopic Partial Nephrectomies Without Pedicle Dissection- Verit et al. Table 1: Demographic and perioperative data of the patients who underwent Laparoscopic partial nephrectomy. Minimum Maximum Median (Mean ± SD) Age (years) 28 79 48.32 ± 13.82 Body mass index (kg/m2) 21.6 45.87 29.1 Size (mm) 12 46 32 Operation time (min.) 90 240 120 Hospital stay (day) 2 10 3 Estimated blood loss (mL) 100 500 200 Decrease in Hg (gr/dL) 1 4,5 2 Follow up (month) 1 50 15 pathologic reports showed renal cell carcinoma (RCC) with subtypes as; Clear cell (n: 50) and Papillary (n: 8) and tumor-negative at the surgical margin, except for two (3.4%). No recurrence was noted at the surgi- cal site during the control radiologic imagings during a mean follow-up of 19.67 ± 13.57 months (range: 1-50 months). Neither urine leakage nor need of peri- or postoperative double J catheter was reported. Pre- and postoperative renal functions did not alter depending on the serum creatinine levels. Clavien scores were noted to be Grade I (n = 43, 74%), II (n = 13, 23%), and III (n = 2, 3%) and were treated conservatively with anti- biotics or blood transfusions, R.E.N.A.L nephrometry scores demonstrated mostly (91.4%) low tumor com- plexity, and the remaining ones were moderate (8.6%), with no high complexity. These data are summarized in Table 2. There was a statistically significant relationship be- tween the R.E.N.A.L score and the duration of hospital- ization, the estimated blood loss and the Clavien score in the positive correlation of 32.6%, 70.4% and 61.9%, respectively (P = .012; P = .001; P = .001)(Table 3). DISCUSSION LPN as a minimally invasive procedure has strict ad- vantages such as short hospital stay, quick recupera- tion and less postoperative discomfort, less blood loss, and no surgical scar compared with an open surgical technique.(2) In this study, we aimed to represent the results of our patients who underwent LPN without hi- lar clamping and dissecting and just targeting the renal mass directly and discussed its possible advantages and disadvantages. Hilar clamping has the advantage of lower blood loss, shorter OT, and better surgical performance despite its disadvantage of possible irreversible renal function loss compared with the unclamped method.(6) However, the classic unclamping method also requires a hilar dis- section step for patient and oncologic safety reasons. Skipping this time-consuming surgical step, which is the dissection of the renal hilus to isolate the renal ar- tery and vein and also the kidney dissection from the surrounding tissues according to the standard LPN, may provide a decreased OT. Present OTs (mean: 139 min) seemed to be a bit short in comparison with some non-ischemic LPN series in the literature (160- 210 min).(14,15) In our opinion, this relatively simpli- fied surgical technique confirms our previous hypoth- esis that cases of cancer of the upper urinary system should not be excluded, even in the initial laparoscopic learning curve, based on the results of our early lap- aroscopic surgical series.(16) Nevertheless, one of the limitations of this modified surgical procedure is that the surgical team should be experienced in both open and laparoscopic surgery because an urgent open pro- cedure may be required in cases of severe bleeding to control the renal pedicle. Thus, instead of a retroperi- toneal approach, a transperitoneal-approach LPN was suggested for immediate control of the renal pedicle. However, any need of changing the planned surgical procedure was reported in our pioneer series. Parallelly, in a robotic assist nephron sparing surgical series with clamping and off-clamping groups, Acar O et al. con- cluded that non-ischemic option could be applied even in initial learning curve but with an expert surgeon in open surgery, however, unlikely to our study, authors preferred hilus dissection to enable rapid hilar control even in off-clamped group.(17) Due to the fact that the present study is a non-ischemic form of LPN, the blood loss is considered to be more than in the ischemic type. (6) Our mean EBL, which was approximately 240 mL, was similar to those of a recent systematic review and meta-analytic study involving mixed LPN studies that included clamped–unclamped and undefined method- ologies (100–400 mL).(18) Furthermore, Aron et al. re- ported EBL as 300 mL in their small series (n = 12) with unclamped or early unclamped LPN.(19) However, there were some discordance between present EBL and Hb values. Most of the present blood lost was represent the measurement of the liquid at the aspiration tube af- ter the subtract of the irrigation water. Thus calculation discordance should bear in mind. On the other hand, some bleeding might spread over the abdomen and also the coagulated ones that skiped from the aspiration and the postoperative suction drainage. All in all, we think that the drop in serum Hb levels (mean approximately 2 g/dl) were more predictive to monitor the blood loss in our study. A small, but significant, number (19%) of our patients needed blood transfusions due to a decrease in serum hemoglobin level below 10 g/dL. Our blood transfusion rate (BTr: 19) was slightly higher than that in the high-volume study (BTr: 11) that involved the combined cases who underwent either clamped or un- clamped LPN and robotic-assist LPN.(20) On the other hand, although it was not clearly reported in the liter- ature, it should be considered that hilar dissection can expose the main renal vascularity to some very serious complications such as renal vascular perforations and thrombosis (e.g., main or segmental renal artery or Laparoscopic Partial Nephrectomies Without Pedicle Dissection- Verit et al. Table 2: Tumor location, pathologic report, Clavien and R.E.N.A.L (Radius of the tumor size / Exophytic / Nearness to collecting system / Anterior / Location) nephrometry scores of the patients. n % Tumor side Right 29 50 Left 29 50 Tumor location Lower pole 24 41 Middle pole 14 24 Higher pole 20 35 Pathology of surgical margin (SM) Eneculation 18 31 SM (-) 38 66 SM (+) 2 3 Renal Nephrometry (R.E.N.A.L) score Low complexity (4-6) 53 91 Moderate complexity (7-9) 5 9 Clavien-Dindo grading system (n) Clavien 1 43 74 Clavien 2 13 23 Clavien 3 2 3 R.E.N.A.L score r p Hospital stay (day) 0,326 ,012* Estimated blood loss (mL) 0,704 ,001* Clavien score 0,619 ,001* r: Spearman’s rho correlation coefficient * p < 0.05 Table 3: The correlation of R.E.N.A.L score with duration of hospi- talization, estimated blood loss and Clavien score Laparoscopic & Robotic Urology 130 Vol 16 No 02 March-April 2019 131 vein, gonadal artery, lumbar vein), which may increase the morbidity rates of the standard LPN and possibly lead to urgent nephrectomies, carrying a perioperative mortality risk. For example, in a large series with over 150 cases for planned LPN, some of them (3.3%) were switched to laparoscopic nephrectomies (LN) for unde- fined reasons during the operation.(14) In a meta-analy- sis, this conversion rate from LPN to LN is defined as 0% to 12%.(18) Nevertheless, we think that the surgical site hemorrhage in the present study cannot have result- ed in unnecessary nephrectomies even if the surgical strategy changed to the open procedure perioperatively due to the involvement of a few segmental arteries. Be- sides, the rate of switching from LPN to open surgery noted in the literature is 0% to 14%. Surprisingly, the reports that were close to the high point of the range were relatively recent reports instead of reports from the beginning of the laparoscopic revolution period. (18,21,22) It should be expected that these aforementioned rates LPN to LN or open surgery decrease to zero during the laparoscopic learning curve of the urology clinics. However, conversely, in the assessment of these data, it can be noted that LPN always has the risk of converting to LN and open procedure as partial/total nephrecto- mies in any clinic and with any surgeon. Furthermore, postoperative lymphatic leakage (0.5%) is another pos- sible special morbidity for conventional LPN, but not the present one, due to the destroying of the small vas- cularities, including the lymphatics of the renal hilum. (18,22) Urinary leakage claimed to be more often in LPN series in comparison with the open PN(23), however we had any this kind of complication, probably, due to the reason that our series involved mostly uncomplicated small exophitic masses. The resection site hemorrhage during the procedure can be regarded as a frustrating factor for a safe surgical margin, and thus it might be claimed that there may be an increased risk for residue tumor at the resection re- gion. As supporting this determination, enucleation of the renal masses occurred in 1/3 of our cases and could be regarded as oncologically unsafe procedure. Nev- ertheless, Zhang K reported that even 1mm inside the normal tissue was enough for a safe surgical margin. (24) However, all of our patients’ (except for two, 3.4%) pathology reports showed a negative surgical margin. This positive surgical margin rate was reported in a wide range as 0–11 in an LPN series.(18) Moreover, there was no reported recurrence in the original operation re- gion in our series with a mean of 20 months follow-up. On the other hand, in connection with one of the aims of this study, enucleation can be regarded as another nephron-sparing surgery (NSS) option that theoretically involves any functional cancer-free nephron inside the pathologic specimen. Renal hilus dissection for controlling renal pedicle ei- ther for the requirement of warm ischemia or switching to LN in the case of uncontrolled perioperative severe renal bleeding is regarded as a sine qua non of standard LPN. Moreover, the literature point to the popularity of non-ischemic LPN for nephron-sparing concerns.(25) The present surgical approach for low complex small masses cannot be expected to result in renal functional abnormalities per-operatively and can be regarded as al- most purely nephron sparing. Nonetheless, non-ischem- ic LPN also drives through the renal pedicle exposition after a careful dissection. On the other hand, we think that severe life-threatening renal hemorrhage is not possible in small (≤ 4 cm) exophitic lesions of the kid- ney based on our results; thus, hilar controlling and the dissection for exposing the main renal vascularity are not mandatory. These masses in the present group were mostly (91%) low complexity according to R.E.N.A.L nephrometry scores, which is a classification for pre- dicting blood loss and the type of surgery required (ei- ther open or LPN).(26) R.E.N.A.L nephrometry scores were created to standardize anatomical tumor defini- tion. In our opinion, the R.E.N.A.L score may also help in selecting patients for our modified LPN technique. Furthermore, in a study evaluating standard LPN (with hilus control) in two groups with Renal mass below and above 4 cm, authors interestingly found that there was no differences in the peroperative complications in se- lected cases.(27) Another disadvantage of renal hilus dissection for re- nal pedicle control is the possible difficult exposition in the ipsilateral secondary operations in cases of re- currence due to residual cancer or micro-multifocali- ties.(28) However, the primary tumor-focusing surgery provides a safer operation site via virgin renal hilus for the secondary procedures such as LPN or LN. Finally, defined tumor-focusingLPN without renal pedicle ex- position is convenient for robotic-assist LPN and also the principles of laparoendoscopic single-site surgery (LESS). Kawai et al. described LESS LPN without hi- lar clamping in seven patients with similar tumor size (≤ 4 cm). No patient required blood transfusion, but one of them was converted to conventional LPN due to massive bleeding. However, it was unclear whether they prepared the renal pedicle initially and, in addi- tion, whether they preferred a special cutting instrument such as a microwave tissue coagulator.(29) We did not use special instruments; all procedures were conduct- ed via the available standard surgical instruments. In regard to the reducing the invasiveness of the proce- dure, we should mention that all of our procedures were conducted using three to four ports, but not a fifth one. The fifth trocar for hilar clamping was standard in the conventional LPN procedure.(5) With respect to present technique involving zero is- chemia with zero hilar dissection, some authors intro- duce the method as selective renal parenchyma com- pression with special clamps (Simon's clamp) that provide a relatively safe alternative to local ischemia, far from the renal pedicle inn the resection region, espe- cially in polar renal tumors.(30) However, an advantage in the present procedure is that there is no need for a special instrument through a new port site and, more- over, local ischemia caused by Simon’s clamp may be harmful to the local nephrons distal to the clamp. Fur- thermore, the clamp itself can cause massive bleeding and nephron destruction. Segmental artery clamping is another way to increase the effect of NSS, but it cannot be considered less invasive.(31) Another recent effort for NSS during LPN is “controlled hypotension anesthe- sia,” which reduces the renal circulation during the pro- cedure. This method is performed without renal hilar clamping, but with hilar control.(32) The other challeng- ing minimally invasive procedures for nephron sparing, such as cryoablation and radiofrequency ablation, mi- crowave thermotherapy, and laser interstitial thermal therapy, can be regarded as ongoing discussion topics, but have not been included in this article.(6) Laparoscopic Partial Nephrectomies Without Pedicle Dissection- Verit et al. The main limitation of this study was its uncontrolled retrospective design with limited subjects. Thus some data seemed to have discordance such as the EBL and decreased Hb levels, although the possible explanations have been discussed. Furthermore, as another restric- tion, all cases were not conducted by single surgeon. To conclude, we found that tumor-focusing LPN is pre- ferred for small-sized exophitic renal masses, and that this procedure is in accord with nephron-sparing prin- ciples. The results of this pioneer study should be con- firmed by large-volume prospective controlled studies with groups of conventional LPN and tumor-focusing LPN with the same tumor sizes and locations. CONCLUSIONS Despite the relatively high transfusion rate, this sim- plified LPN technique can be an alternative option and seemed to be without disrupting either patient or onco- logic safety, especially for uncomplicated renal masses. REFERENCES 1. Kamachi K, Kojima K, Nishijima A, Takeshita M, Ando T, Kimura S. Small lymphocytic lymphoma presenting as bulky renal incidentaloma. Int J Hematol 2014; 100:107- 8. 2. Gill IS, Kavoussi LR, Lane BN, et al. 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