Correspondence: Soroush Rais-Bahrami, The Arthur Smith Institute for Urology, Hofstra North Shore-LIJ School of Medicine, 450 Lakeville Rd, Suite M-41, New Hyde Park, NY 11040, USA.e-mail: firstname.lastname@example.org
What's known on the subject? and What does the study add?
Laparoendoscopic single-site (LESS) surgery has been used by urologists for a broad range of operations including LESS partial nephrectomy (LESS-PN). To date, experiences of LESS-PN have been presented as small series or as a subset of larger heterogeneous operative experiences, which have shown the overall feasibility and safety of this novel technique.
We report our experience with LESS-PN with complete pathological resection and excellent short-term oncological and renal functional outcomes in the select patient population who underwent this minimally invasive approach.
To present our experience of transumbilical laparoendoscopic single-site (LESS) partial nephrectomy (PN) with pathological and short-term oncological and renal functional outcomes.
Patients and Methods
In all, 15 LESS-PNs were performed for cT1a tumours between July 2008 and August 2011 by one surgeon.
All patients underwent transumbilical LESS using a 5-mm flexible-tip laparoscope and a combination of flexible and conventional laparoscopic instruments.
The technique for transperitoneal LESS-PN otherwise replicated conventional laparoscopic PN.
Demographic, perioperative, and postoperative variables were recorded and analysed.
Of the 14 patients (eight men), undergoing 15 distinct LESS-PN, the mean (sd) age was 57.9 (8.7) years and the mean (sd, range) tumour size resected was 2.4 (0.8; 1.2–4.0). There were 12 renal cell carcinomas, two angiomyolipomas, and two metanephric adenomas on final pathology, all with negative margins.
The mean (sd) operative duration was 169 (47) min with a mean (sd, range) warm ischaemia time of 14.7 (13.4; 0–37) min; bull-dog clamps were used for hilar-control in nine cases with the remaining six cases done without hilar vascular clamping.
The mean (sd) estimated blood loss in this series was 293 (325) mL (median 200 mL) and no cases required intraoperative or postoperative blood transfusions.
The mean (sd) hospital stay was 2.7 (0.8) days and mean inpatient analgesic requirement in morphine equivalents was 21.7 (11.6) mg.
Follow-up surveillance imaging showed no recurrence at a mean (sd, range) follow-up of 18.3 (12.2; 6–36) months and a negligible change in serum creatinine (<0.1 mg/dL) at a mean (sd, range) follow-up of 17.1 (11.9; 1–36) months.
LESS-PN is a feasible and effective operation, providing complete oncological resection along with excellent short-term oncological and renal functional outcomes.
Since the first reported use of laparoscopy for extirpative renal surgery in 1991, laparoscopic techniques have been widely adopted within the urological community and significant advances in the field of minimally invasive surgery have been made by urologists .
Laparoscopic partial nephrectomy (LPN) is an ever increasingly used treatment option in the management of small renal masses, shown to render equal oncological efficacy with improved convalescence compared with open PN . Conventional laparoscopic procedures commonly employ the use of three to five ports for transumbilical access allowing for triangulation of operative instruments within the laparoscopic field of view.
With the development of laparoendoscopic single-site (LESS) surgery as a means to further reduce morbidity and improve cosmetic outcomes, there have been many reports of LESS techniques used for various urological operations. Several series of LESS PN (LESS-PN) have been presented combined with a heterogeneous batch of urological LESS procedures . In the present report, we focus specifically on our initial experience with LESS-PN, presenting our short-term oncological and renal functional outcomes.
Patients and Methods
All cases of LESS-PN performed at our institution between July 2008 and August 2011 were included in the present study. These cases were all patients of one surgeon (L.R.), who previously had experience with advanced conventional laparoscopy as well as experience with extirpative and reconstructive LESS procedures for both benign and malignant indications.
The patients included in this study all presented with renal masses suspicious for RCC that were deemed amenable to LPN based upon axial imaging, either contrast-enhanced CT or MRI. After electing to undergo extirpative treatment, patients were specifically selected to undergo LESS-PN based upon patient characteristics including prior surgical history, body habitus, and surgeon-determined ease of tumour resectability (size, exophytic nature, and proximity to hilar vessels) yielding a very highly selected group of patients. In addition, all patients provided informed consent to undergo LESS-PN understanding the intended surgical approach via a single-site, as well as the potential need for additional trocars as an intraoperative conversion to conventional LPN or open surgery.
All data was collected prospectively and maintained in a patient de-identified database as approved by the Institutional Review Board. Data collection included patient demographics, preoperative tumour characteristics, perioperative parameters, pathological diagnoses, pre- and postoperative measures of renal function, and postoperative oncological follow-up.
The following patient demographics were collected: age, sex, body mass index (BMI), American Society of Anesthesiologists (ASA) score, and history of prior abdominal surgeries. Preoperative tumour characteristics collected include side of the affected kidney, clinical stage, and greatest diameter of tumour.
Perioperative parameters recorded and analysed included operative duration, estimated blood loss (EBL), warm ischaemia time (WIT), intraoperatively measured urine output, intraoperatively administered i.v. fluid volume, intraoperative or postoperative inpatient transfusion data, early complications <30 days of surgery, intraoperative conversion to conventional laparoscopy with additional trocar insertion, pre- and postoperative serum haematocrit levels, length of stay (LOS), postoperative pain assessed as a daily mean pain visual analogue scale (VAS) score, and postoperative inpatient analgesic requirement calculated in morphine equivalents. All complications were classified as intraoperative, immediate postoperative defined as complications during the inpatient convalescence period, or early postoperative defined as complications after discharge but <30 days of surgery. Complications were denoted with grade of severity based on the Clavien-Dindo classification.
Pathological diagnoses entailed the tumour histological subtype, greatest dimension, margin status, and tumour grade and stage when applicable.
Renal function was determined by measurement of serum creatinine preoperatively, in the immediate postoperative period as an inpatient, and at routine outpatient follow-up appointments. The most recent serum creatinine available, with its associated duration of follow-up, was used to calculate the interval change in serum creatinine.
Postoperative oncological follow-up was documented as any outpatient follow-up appointments with available axial imaging study evaluating for local or distant tumour recurrence including ultrasonography, CT, and MRI. All patients underwent postoperative surveillance with either CT or MRI during the first year after surgery before transitioning to ultrasonographic surveillance.
All cases of LESS-PN were achieved with transperitoneal access, using either a combination of one 12-mm and two 5-mm low-profile trocars clustered at a single periumbilical site (Fig. 1) or via a Gelpoint (Applied Medical; Rancho Santa Margarita, CA, USA) device designed to accommodate multiple trocars through a single-site allowing for LESS surgery. For all cases, a 5-mm flexible-tip laparoscope and a combination of flexible and conventional laparoscopic instruments were used. After achieving transperitoneal access, LESS-PN follows the previously described technique of a standard transperitoneal LPN with few modifications . The 12-mm trocar allowed for ‘bulldog’ clamp placement for hilar-control during tumour resection and completing the renorrhaphy, used in nine cases. The remaining five cases were done without clamping hilar vessels as previously described . Renorrhaphy was accomplished using an absorbable polyglactin suture in an interrupted fashion secured with dissolvable Laparoties (Ethicon). At the end of the case, closed suction Jackson-Pratt drains were placed through a separate stab incision or via a 5-mm periumbilical port site in cases with entry into the urinary collecting system.
Patient demographics and tumour characteristics are summarised in Table 1. In all, 15 procedures were performed on 14 patients as one patient had LESS-PN performed 3 months apart on contralateral kidneys for the treatment of bilateral synchronous renal masses. The mean age of patients was 57.9 years. Patients included in the series were mainly overweight and obese with a mean BMI of 29.3 kg/m2. Three patients in the group had undergone prior abdominal surgery, two laparoscopic (cryoablation of contralateral renal mass and cholecystectomy) and one patient who had had a previous open appendectomy and umbilical hernia repair. All patients underwent surgery for clinical T1a renal lesions suspicious for RCC. Of the 15 procedures performed, one case involved PN of two masses from the same kidney resulting in 16 total tumours resected in the present series. The mean preoperative tumour size was 2.3 cm.
Table 1. Patient demographics and tumour characteristics.
*One patient with prior laparoscopic cryoablation of contralateral renal mass and one patient with prior laparoscopic cholecystectomy. †One patient with prior open appendectomy and open umbilical hernia repair.
Table 2 shows the perioperative parameters. The mean operative duration was <3 h with a mean (sd) EBL of 293.3 (325.1) mL largely skewed by a single off-clamp case with an EBL of 1300 mL (median EBL 200 mL). No patients required intraoperative or postoperative blood transfusions. Intraoperatively, one patient, who had multiple prior open abdominal surgeries required extensive adhesiolysis and for this reason was converted to conventional LPN. In this case, two additional working trocars were inserted, one in the subxyphoid position and one in the ipsilateral midaxillary line at the level of the umbilicus allowing for optimal triangulation of working instruments. Also, the 12-mm periumbilical working port was then used for introduction of a rigid 10-mm laparoscope.
Table 2. Perioperative variables.
Mean (sd; range):
Operative duration, min
167.3 (45.5; 120–267)
293.3 (325.1; 50–1300)
Total series, n = 15
14.7 (13.4; 0–37)
Off-clamp, n = 6
Hilar-control, n = 9
24.6 (6.5; 17–37)
Intraoperative urine output, mL
230 (83; 50–400)
Intraoperative i.v. fluids, mL
2120 (750; 1200–4000)
Intraoperative and postoperative in-hospital transfusions
Postoperative <30 days
1/14 – wound dehiscence requiring packing
2/14 – one re-admission for flank pain/urinoma requiring ureteric stent insertion and one delayed bleed requiring angioembolisation of a pseudoaneurysm
One patient had a wound dehiscence during the postoperative period before being discharged (Clavien-Dindo Grade 2) that required wound packing and home nursing services. There were two additional complications in the early postoperative period (<30 days) but after discharge from hospital (both Clavien-Dindo Grade 3b). These included a symptomatic perinephric urinoma requiring re-admission and ureteric stent insertion, and a delayed bleed from a pseudoaneurysm requiring re-admission and selective angioembolisation by interventional radiology. The mean LOS was 2.7 days, but was most commonly 2 days. There was a notable downtrend in the mean patient-reported pain VAS score when trended by postoperative day (Fig. 2). All patients were discharged with pain well controlled (<2 on a 10-point scale) on oral analgesics.
Pathologically, 12 of the 16 masses resected were RCCs (eight, clear cell; one, papillary type 1; two papillary type 2; and one chromophobe). Four tumours were benign (two angiomyolipomas and two metanephric adenomas), with the two metanephric adenomas in the same patient who had two masses resected during the same LESS-PN. All tumours had negative margins on final pathology.
No patients had tumour recurrence on postoperative imaging with a mean (sd) follow-up of 18.3 (12.2) months. At a mean (sd) laboratory assessment follow-up of 17.1 (11.9) months, the mean (sd) change in serum creatinine was 0.06 (0.20) mg/dL (Table 3).
Table 3. Postoperative follow-up and associated oncological and renal functional outcomes.
Mean (sd; range) duration follow-up, months
Mean (sd; range) Δ serum creatinine, mg/dL
0.06 (0.20; –0.3 to 0.2)
17.1 (11.9; 1–36)
Tumour recurrence, n
18.3 (12.2; 6–36)
LESS surgery was developed as an evolutionary advance in laparoscopy with the goal of further minimising convalescence and improving cosmetic outcomes as the underlying goal of minimally invasive surgical techniques. Despite the goals of the LESS approach, any extirpative renal surgery with oncological indications maintains the ultimate goal of curative oncological outcomes.
Most published LESS experiences discussing LESS-PN have been reported as heterogeneous mixtures of cases performed at centres with early series of urological LESS surgery [6-8]. Recently, an international multi-institutional experience with >1000 cases was reported by Kaouk et al. . In all these series, LESS extirpative renal surgery was a subset of the overall experience reported. Specifically, LESS-PN represented a minority of the cases, accounting for between 6 and 27%. Oncological outcomes after LESS-PN are most commonly reported as final pathological findings, rarely as postoperative clinical or radiological follow-up evaluating for recurrence or disease progression.
Papers specifically discussing LESS-PN have begun to emerge. Recently, Kaouk and Goel  reported their experience of seven LESS-PNs of which five were single-site laparoscopic cases, and two used the DaVinci robotic platform for single-site robot-assisted laparoscopy; the pathology found in this series revealed one benign cyst and six cases of RCC, with one focal positive margin on final pathology, which was negative on intraoperative frozen-section analysis.
Similarly, Han et al.  published a series of 16 patients who all underwent robotic LESS-PN, of whom 14 had RCC, one had an angiomyolipoma, and one had xanthogranulomatous pyelonephritis on pathological examination; all had surgical margins negative for malignancy. There was no notation of other oncological outcomes or renal functional follow-up in either of these LESS-PN series probably due to the relative novelty and resultant short-term follow-up of this procedure.
The only dedicated report with oncological outcomes after any LESS oncological renal surgery was that of LESS radical nephrectomy published by Greco et al. . They reported their experience with 33 patients who underwent LESS radical nephrectomy for a mean (sd) preoperative tumour size of 5.1 (1.4) cm. On final pathology, all specimens were RCC. No patients in their patient cohort had tumour recurrence or port-site metastases with a mean (sd) follow-up of 13.2 (3.9) months. This study by Greco et al. represents a much necessary move toward validation of the oncological efficacy of LESS surgery. We aimed to evaluate our experience with LESS-PN in a similar way, reporting not only outcomes of the final pathology, which document complete resection, but also postoperative radiological surveillance to show cancer-free survival for the duration of follow-up available.
A secondary goal to consider is preservation of renal function, as this is the basis of nephron-sparing surgery when oncologically feasible and sound. This aim of increasing the use of nephron-sparing surgery has expanded the indications for LPN in the presence of a normal contralateral kidney, when the targeted mass is deemed amenable to attempt PN [12, 13]. In addition to rendering patients with PN when possible, various technical modifications have been under investigation to improve postoperative renal functional outcomes by minimising ischaemia and reperfusion-induced tissue injury. In the conventional LPN literature, early unclamping, on-demand clamping, and ‘off-clamp’ or ‘zero-ischaemia’ approaches have been used and suggested to render less renal functional decline postoperatively [5, 14-16].
The goal of optimising overall renal function after LPN has been extended to LESS-PN. Cindolo et al.  published their technical approach to off-clamp LESS-PN initially in 2011 for treatment of a symptomatic angiomyolipoma. This group has since presented their expanded experience with six patients having undergone LESS-PN without hilar vascular occlusion . Comparable with the subset of patients in the present series who underwent off-clamp LESS-PN, Cindolo et al. reported similar operative durations, blood loss, and no cases required transfusion of blood products. However, in the Cindolo et al. series of six cases, one was converted to conventional multiport laparoscopy (17%) and two others required insertion of a single additional access port (33%). We have shown that in specially selected cases, where tumour characteristics appear to be amenable to an off-clamp technique, LESS does not preclude this technique from being used successfully. In the overall patient cohort, with a mean WIT of <30 min, combining the off-clamp LESS-PN and the hilar-control LESS-PN patients, there was a negligible change in serum creatinine levels at the last follow-up. Estimated GFR was calculated based upon available parameters, but closely paralleled the change in serum creatinine concentration, as the patient weight and age were negligibly altered during the period of follow-up.
A vital assessment with any technical modification like LESS is monitoring of patient safety. We carefully examined the rate of intraoperative conversions as well as intraoperative, in-hospital, and short-term (<30 days) postoperative complications. In the present series, one patient was converted from hilar-control LESS-PN to conventional multiport laparoscopy (6%), which was the only case that required any intraoperative additional trocar placement. The indication for conversion was a failure to progress effectively via a single-site approach due to intra-abdominal adhesions from prior surgeries necessitating extensive adhesiolysis. Conversion from LESS-PN cohorts to conventional laparoscopy was reported in 6.8–12.5% in large series of urological LESS that focused on assessing complications and conversions [19, 20]. This number varies widely due to differing definitions of ‘conversion’ based on use of accessory ports in LESS cases.
In the series of exclusively robotic LESS-PN, conversion to open surgery via ‘mini-incision open access’ was reported in two cases (14.3%); however this group did not convert any cases to multiport laparoscopy . This may reflect a difference in baseline comfort with advanced laparoscopy, as all of these robot-assisted LESS cases were converted directly to an open approach rather than the lower rate of conversion stated in other series of between 0 and 1.5% [19, 20].
In the present series, no perioperative transfusions were required. There were only three postoperative complications <30 days after surgery. One patient had a wound dehiscence while in the hospital, at the access site, requiring wound packing which extended the LOS. The more significant complications, a urine leak and a delayed bleed from a pseudoaneurysm, both clinically manifested after discharge from the hospital and required re-admission and a secondary procedure.
Greco et al.  reported one case of a LESS-PN (4%) that had a urine leak requiring ureteric stent insertion similar to the single case in the present series. Urinary fistula rates are lower in the reported series of LPN . This is probably due to the overall rarity of this complication and limited sample size in all the reports of LESS-PN to date.
Postoperative haemorrhage from LPN has been reported in 4.2–6% of cases, but specifically, arteriovenous fistula and pseudoaneurysm formation can present with a delayed bleed into the urinary tract in 2% of cases . This delayed bleeding manifestation has been defined as gross haematuria from an upper tract source at least 7 days postoperatively after LPN. These cases of delayed bleeding, if persistent despite conservative measures, are best managed by selective angiography and angioembolisation if the source is identified. This algorithm was used for the one case of LESS-PN with this recognised complication.
Limitations of the present study include the highly selected patient cohort, which introduces a potential selection bias compared with mature series of LPN in which body habitus, prior surgical history, comorbidities, and tumour characteristics play less of a role in case selection. Although, oncological and renal functional follow-up is presented in the present study, adding to the proof-of-principle supporting LESS-PN as an effective approach, the duration of follow-up is short and will need continued investigation as the population matures and follow-up lengthens.
To date, LESS urological surgery, adopted with the goal of improving cosmetic outcomes and improving postoperative convalescence, has collectively been proven to improve cosmesis subjectively but not yet shown to uniformly decrease morbidity . Some series have shown improvement in postoperative analgesic requirements and patient reported pain scores while others have shown equal measures when compared with conventional laparoscopy. The feasibility of various LESS operations has been proven . We further support the feasibility and success of LESS-PN showing adequate oncological and renal functional outcomes. In the future, larger series and comparative studies are necessary to assess the value of LESS approaches compared with conventional laparoscopy.
In conclusion, LESS-PN is a feasible and effective operation when performed by a select cohort of surgeons who have had adequate experience with extirpative and other reconstructive LESS procedures, providing complete oncological resection and excellent short-term oncological outcomes. In our early experience with LESS-PN for cT1a renal tumours, perioperative parameters analysed were acceptable, and expected to improve with progression on the learning curve. Patients had a rapid convalescence with discharge from the hospital most commonly on the second postoperative day. Renal functional outcomes were comparable with reported series for conventional LPN and the LESS technique did not preclude use of the off-clamp approach.