Articles

Platinum Priority – Urothelial Cancer
Editorial by Jonathan A. Coleman on pp. 517–518 of this issue

Laparoendoscopic Single-Site Upper Urinary Tract Surgery: Assessment of Postoperative Complications and Analysis of Risk Factors

By: Francesco Grecoa lowast 1 , Luca Cindolob 1, Riccardo Autorinoc, Salvatore Micalid, Robert J. Steinc, Giampaolo Bianchid, Caterina Fanizzae, Luigi Schipsb, Paolo Fornaraa and Jihad Kaoukc

European Urology, Volume 61 Issue 1, March 2012, Pages 510-516

Published online: 01 March 2012

Keywords: Complications, Laparoendoscopic single-site surgery, Upper urinary tract, Outcomes, Standardised criteria

Abstract Full Text Full Text PDF (198 KB)

Abstract

Background

Laparoendoscopic single-site surgery (LESS) has been developed in an attempt to minimise the morbidity and scarring associated with surgical intervention.

Objective

To evaluate the incidence of and the risk factors for complications in patients undergoing LESS upper urinary tract surgery.

Design, setting, and participants

Between September 2007 and February 2011, 192 consecutive patients underwent LESS for upper urinary tract diseases at four institutions.

Measurements

All complications occurring at any time after surgery were captured, including the inpatient stay as well as in the outpatient setting. They were classified as early (onset <30 d), intermediate (onset 31–90 d), or late (onset >90 d) complications, depending on the date of onset. All complications were graded according to the modified Clavien classification.

Results and limitations

The patient population was generally young (mean: 55±18 yr of age), nonobese (mean body mass index [BMI]: 26.5±4.8kg/m2), and healthy (mean preoperative American Society of Anaesthesiologists [ASA] score: 2±1). Forty-six patients had had prior abdominal surgery. Mean operative time was 164±63min, with a mean estimated blood loss (EBL) of 147±221ml. In 77 cases (40%), the surgeons required additional ports, with a standard laparoscopy conversion rate of 6%. Mean hospital stay was 3.3±2.3 d, and the mean visual analogue scale (VAS) score at discharge was 1.7±1.43. Thirty-three complications were recorded—30 early, 2 intermediate, and 1 late—for an overall complication rate of 17%. Statistically significant associations were noted between the occurrence of a complication and age, ASA score, EBL, length of stay (LOS), and malignant disease at pathology. Univariable and the multivariable analyses showed that a higher ASA score (incidence rate ratio [IRR]: 1.4; 95% confidence interval [CI], 1.0–2.1; p=0.034) and malignant disease at pathology (IRR: 2.5; 95% CI, 1.3–4.7; p=0.039) represented risk factors for complications. Poisson regression analysis over time showed a 23% non-statistically significant reduction in risk of complications every year (IRR: 0.77; 95% CI, 0.5–1.19; p=0.242).

Conclusions

Malignant disease at pathology and high ASA score represent a predictive factor for complication after LESS for upper urinary tract surgery. Thus, surgeons approaching LESS should start with benign diseases in low-surgical-risk patients to minimise the likelihood of postoperative complications.

Take Home Message

Malignant disease at pathology and high American Society of Anaesthesiologists score represent predictive factors for complications after laparoendoscopic single-site surgery (LESS) for upper urinary tract disease. Surgeons approaching LESS should start with benign diseases in low-surgical-risk patients to minimise the likelihood of postoperative complications.

Keywords: Complications, Laparoendoscopic single-site surgery, Upper urinary tract, Outcomes, Standardised criteria.

1. Introduction

Laparoendoscopic single-site surgery (LESS) has been developed in an attempt to further reduce the morbidity and scarring associated with laparoscopic surgery [1]. Early clinical series have demonstrated the feasibility of a broad range of LESS urologic procedures [2], [3], [4], [5], [6], and [7]. Few reports have specifically looked at complications after LESS in urology [8]. Irwin et al reported their multi-institutional experience with 125 upper-tract LESS procedures, showing a complication rate of 15.2% [9].

When a new surgical procedure is introduced, there is a need to compare outcomes and complications in a sound and reproducible way. Standardised evaluation tools for outcomes and complications are necessary for achieving this goal. Surgical complications can be reported in a variety of ways, and the means through which data are obtained and reported probably have as much impact on the complication rate as the procedure does [10].

To date, no study has specifically evaluated the risk of complications following LESS. The aim of the present study is to evaluate the incidence of and risk factors for complications in a multi-institutional series of patients who have undergone LESS for upper urinary tract diseases.

2. Materials and methods

2.1. Study design

This was a retrospective analysis of the medical records of consecutive patients who underwent LESS for upper urinary tract diseases at four major institutions between September 2007 and February 2011. All patients gave written informed consent after being informed that the procedure would be attempted via a single incision and counselled that additional incisions could have been necessary.

A prospective purpose-built datasheet was constructed for this study. The following information was collected: age, gender, ethnicity, body mass index (BMI), preoperative conditions (ie, smoking status, diabetes, renal insufficiency, hypertension), pre- and postoperative renal function, prior abdominal surgery, specific comorbidities, American Society of Anaesthesiologists (ASA) score, tumour stage and grade, surgical margin status, specimen weight, operative time, and estimated blood loss (EBL). Additional collected data included intraoperative variables (eg, kind of trocar, placement of trocar, number of additional ports, use of prebent or articulating instruments), preoperative and postoperative serum haemoglobin levels, transfusion data, conversion to open surgery or standard laparoscopy, length of stay (LOS), postoperative pain evaluation based on a visual analogue scale (VAS) score at discharge, incision length, and subjective scar satisfaction. Procedures were categorised as “extirpative/ablative” or “reconstructive.” Moreover, they were scored based on a Likert-type scale from 1 (slightly difficult) to 5 (extremely difficult) according to a previously reported scoring system for laparoscopic surgery [11].

Conversion to open surgery was considered a complication, whereas conversion to standard laparoscopy through the use of more than one additional trocar was not. Both medical and surgical complications occurring at any time after surgery were captured, including inpatient stay as well as in the outpatient setting. They were classified as early (onset <30 d), intermediate (onset 31–90 d), or late (onset >90 d) complications, depending on the date of onset. For late complications, those deemed to be related or possibly related to LESS were captured, regardless of how long after surgery onset occurred.

All complications were recorded with a grade (1, 2, 3a, 3b, 4a, 4b, or 5) assigned according to the modified Clavien-Dindo classification [12]. Specifically, grade 0 identified the absence of any complication; grade 1 identified the presence of any deviation from the normal postoperative course, including the need for pharmacologic treatment other than antiemetics, antipyretics, analgesics, diuretics, electrolytes, or physiotherapy; grade 2 identified complications requiring the use of intravenous medications, total parenteral nutrition, enteral nutrition, or blood transfusion; grade 3 identified complications requiring surgical, endoscopic, or radiologic intervention; grade 4 identified life-threatening complications requiring intensive care or intensive care unit management; and grade 5 identified complications resulting in the death of the patient.

2.2. Statistical analysis

For the whole sample, patients’ baseline characteristics were reported as frequency (percentage) and mean plus or minus standard deviation (SD) for categorical and continuous variables, respectively. Moreover, patient characteristics according to the presence of a complication were recorded and compared with Pearson χ2 test or Fisher exact test for categorical variables and the Mann-Whitney U test for continuous variables.

To identify independent characteristics associated with complications, Poisson regression models with robust error variance were used [13]. Variables with a univariate p value <0.05 were entered into the final model—specifically, gender, age, smoking, presence of comorbidity, BMI, ASA score, malignant disease at pathology, use of an additional port, kind of surgery, and complexity score. Results were expressed as incidence rate ratio (IRR) and 95% confidence interval (CI).

To estimate the probability of complications, cumulative incidence was calculated using the Kaplan-Meier approach. All statistical tests were two-sided, and p values <0.05 were considered significant. All the analyses were performed using SAS v.9.2 (SAS Institute, Cary, NC, USA).

3. Results

3.1. Study population

Our population consisted of 192 patients who underwent LESS for upper urinary tract diseases (Table 1). The patient population was generally young (mean: 55±18 yr of age), nonobese (mean BMI: 26.5±4.8kg/m2), and healthy (mean preoperative ASA score: 2±1). Forty-six patients had had prior abdominal surgery. The procedures were mostly for extirpative surgery (85.4% of cases), including radical nephrectomy (RN; 25.6%), partial nephrectomy (PN; 12.5%), simple nephrectomy (10.9%), and living-donor nephrectomy (14.1%). Reconstructive surgery (14.6% of cases) included pyeloplasty, ureterolithotomy, and nephropexy cases. In 68 cases, the final pathologic evaluation confirmed the presence of malignant disease.

Table 1 Baseline characteristics of patients undergoing laparoendoscopic single-site surgery renal surgery

Variable Value*
Age, yr 55±18
BMI 26.5±4.8
Gender, no. (%):

Female

Male


100 (52.1)

92 (47.9)
ASA score, no. (%):

1

2

≥3


54 (28.1)

97 (50.5)

41 (21.4)
Comorbidities, no. (%):

Smoking

Chronic renal failure

Hypertension

Diabetes


57 (29.7)

18 (9.4)

85 (44.3)

17 (8.9)
Surgical procedures, no. (%):

RN

Living-donor nephrectomy

PN

Pyeloplasty

Simple nephrectomy

Cyst marsupialisation

Cryoablation

Adrenalectomy

Renal biopsy

Nephroureterectomy

Ureterolithotomy

Nephropexy


49 (25.6)

27 (14.1)

24 (12.5)

22 (11.5)

21 (10.9)

16 (8.3)

9 (4.7)

6 (3.1)

6 (3.1)

6 (3.1)

4 (2.1)

2 (1.0%)
Kind of procedure, no. (%):

Reconstructive

Extirpative
28 (14.6)

164 (85.4)
Use of additional ports, no. (%) 77 (40.1)
Kind of disease, no. (%):

Malignant disease at pathology

Benign conditions


68 (35.4)

124 (64.6)
Complexity score, no. (%):**

1–2

3–5


112 (58.3)

80 (41.7)

* Data are reported as mean plus or minus SD for continuous variables and number (percentage) for categorical variables.

** See reference [11].

BMI=body mass index; ASA=American Society of Anaesthesiologists; RN=radical nephrectomy; PN=partial nephrectomy; SD=standard deviation.

3.2. Intraoperative and postoperative characteristics

Mean operative time was 164±63min, with a mean EBL of 147±221ml. In 77 cases (40%), the surgeons required additional ports, with a standard laparoscopy conversion rate of 6% (12 of 192). The reasons for the conversion to standard laparoscopy were difficulties during dissection and exposure (four cases) and demanding suture (eight cases). Mean hospital stay was 3.3±2.3 d, and the mean VAS score at discharge was 1.7±1.43. The mean length of skin incision was 3.97±1.33cm. Data concerning subjective scar satisfaction (available from 91 patients) showed that they were enthusiastic (56%), very satisfied (26%), or satisfied (18%).

3.3. Complications

Thirty-three complications were recorded—30 early, 2 intermediate, and 1 late—for an overall complication rate of 17%. A detailed description is provided in Table 2. Statistically significant associations were noted between the occurrence of a complication and age, ASA score, EBL, LOS, and malignant disease at pathology (Table 3). No associations between complications and BMI, comorbidities, kind of surgery (extirpative vs reconstructive), use of additional ports, or complexity score were recorded.

Table 2 Complications*

Complication No. of patients Action
Clavien grade 1: 4
Small incisional hernia 1 Observation
Ileus 1 Observation
Flank pain 2 Analgesics
Clavien grade 2: 22
Urinary leakage after ureterolithotomy 1 Prolonged drainage
UTI 1 Antibiotics
Acute gastritis 2 PPIs
Postoperative anaemia 18 Transfusion
Clavien grade 3a: 2
Urinary fistula after NSS 1 Ureteral stent placement
Postoperative bleeding with sepsis 1 Angioembolisation, transfusion, and antibiotics
Clavien grade 3b: 2
Retained sponge 1 Colpotomy opening
Postoperative incisional hernia 1 Surgical repair
Clavien grade 4: 1
Cerebral stroke 1 Admission to stroke unit
Conversion to open surgery 4
Intraoperative bleeding 3
Constant CO2 leakage 1
Overall complication rate 33 of 192 (17%)

* Some patients had multiple complications (eg, conversion to open surgery and transfusion).

UTI=urinary tract infection; PPI=proton pump inhibitor; NSS=nephron-sparing surgery.

Table 3 Patient characteristics according to complication

Patients without complications (n=159)* Patients with complication (n=33)* p **
Continuous variables:
Age, yr 53.8±17.5 60.5±17.6 0.038
BMI 26.4±4.4 27.3±6.7 0.883
Operative time, min 162.7±65.2 174.7±57.2 0.295
EBL, ml 118.9±179.9 276.9±329.9 0.0124
LOS, d 2.9±1.4 5.9±3.4 <0.0001
Categoric variables, no. (%):
Gender: 0.282
Female 80 (50.3) 20 (60.6)
Male 79 (49.7) 13 (39.4)
ASA score: 0.067
1 47 (29.6) 7 (21.2)
2 83 (52.2) 14 (42.4)
≥3 29 (18.24) 12 (36.4)
Smoking 49 (30.8) 8 (24.2) 0.4
Chronic renal failure 12 (7.6) 6 (18.2) 0.093
Hypertension 68 (42.8) 17 (51.5) 0.373
Diabetes 13 (8.2) 4 (12.1) 0.503
Comorbidity (one or more) 70 (44) 19 (57.6) 0.165
Procedures 0.791
Reconstructive 24 (15.1) 4 (12.1)
Extirpative 133 (83.7) 29 (87.9)
Not applicable 2 (1.3) 0 (0.0)
Use of additional port 65 (40.9) 12 (36.4) 0.63
Kind of disease: 0.001
Malignant disease at pathology 48 (30.2) 20 (60.6)
Benign conditions 111 (69.8) 13 (39.4)
Complexity score: 0.8222
1–2 93 (58.5) 20 (60.6)
3–5 66 (41.5) 13 (39.4)

* Data are reported as mean plus or minus SD for continuous variables and number (percentage) for categorical variables.

** χ2 test or Fisher exact test for categorical variables and Mann-Whitney U test for continuous variables.

BMI=body mass index; EBL=estimated blood loss; LOS=length of stay; ASA=American Society of Anaesthesiologists; SD=standard deviation.

Univariable and multivariable analyses showed that a higher ASA score (IRR: 1.4; 95% CI, 1.0–2.1; p=0.034) and malignant disease at pathology (IRR: 2.5; 95% CI, 1.3–4.7; p=0.039) represented risk factors for complications (Table 4).

Table 4 Univariate and multivariate analysis for complications after laparoendoscopic single-site surgery renal surgery

Variable Univariate Multivariate
IRR LLC ULC p value IRR LLC ULC p value
Sex
Female 1.415 0.748 2.680 0.2861
Male 1
Age 1.020 0.999 1.041 0.0662
Smoking
Yes 0.752 0.361 1.566 0.4468
No 1
Presence of comorbidity
Yes 1.555 0.829 2.918 0.1688
No 1
BMI 1.028 0.965 1.095 0.3881
ASA score 1.625 1.111 2.378 0.0124 1.470 1.021 2.118 0.0384
Malignant disease at pathology
Yes 2.806 1.490 5.281 0.0014 2.531 1.347 4.759 0.0039
No 1 1
Use of additional port
No 0.853 0.446 1.631 0.6316
Yes 1
Kind of surgery
Extirpative 1.253 0.477 3.290 0.6469
Reconstructive 1 1 1
Complexity score
3–5 0.93 0.49–1.76 0.8225
1–2 1

IRR=incidence rate ratio; LLC=lower limit of confidence; ULC=upper limit of confidence; BMI=body mass index; ASA=American Society of Anaesthesiologists.

The Poisson regression analysis over time showed that there is a 23% non-statistically significant reduction in risk of complications every year (IRR: 0.77; 95% CI, 0.5–1.19; p=0.242; Fig. 1). A comparison between the incidence of complications between the early phase (first 20 cases) and the following cases of each centre was insignificant (p=0.235).

gr1

Fig. 1 Cumulative incidence of complications after laparoendoscopic single-site upper urinary tract surgery.

4. Discussion

Over the past 4 yr, LESS techniques in urology have been popularised worldwide. In a recent literature review, it was reported that the outcomes after single-site surgery in non-high-risk patients seem to be comparable to conventional laparoscopy [1]. LESS series in urologic literature have been reported for well-selected patients [2], [3], [4], [5], [6], and [7], even if experience with LESS RN in transplant patients has been also described [14].

As a general principle, all eligible laparoscopic surgery patients can be considered for LESS depending on the surgeons’ experience. In the updated recommendations from the Endourological Society NOTES (natural orifice transluminal endoscopic surgery) and LESS Working Group and European Society of Urotechnology NOTES and LESS Working Group, it has recently been pointed out that LESS is suitable in appropriately selected patients, including thinner patients with limited prior abdominal surgery [15].

The true incidence of complications related to LESS needs to be more clearly defined. Even if complications have been reported for several series of specific LESS procedures [1], few studies have specifically addressed the issue of complications with LESS. As outcomes data accumulate with this approach, it will be critical for studies to embrace standardised complications-reporting methodologies, allowing for meaningful comparisons across institutions.

Irwin et al. [9] recently reported their experience with 125 upper-tract LESS procedures, showing a complications rate of 15.2% and conversion to laparoscopy in seven patients (5.6%). Three of the seven patients who required conversion to laparoscopy developed postoperative complications (Clavien grade 2 in two and 3a in one). Limitations of this study included the inability to standardise LESS patient-selection criteria, instrumentation, and surgical technique as well as the lack of available complete data from a control group for comparison. The authors concluded that LESS appears to be associated with higher rates of complications than in mature laparoscopic series, but conversions occur infrequently as a reflection of stringent patient selection.

The more widespread use of grading schemes in reporting complications has facilitated standardisation to some degree [10] and [12]. The present study represents the first large multi-institutional analysis specifically evaluating risk factors for complications consequent to LESS for upper urinary tract diseases. The overall complication rate was 17%. Nevertheless, major complications were represented by low-grade (Clavien 1 and 2) incidents. Only two factors proved predictive for complications: a high ASA score, which is not surprising, and malignant disease at pathology.

Several series have suggested the feasibility of LESS for the management of renal malignancies [2], [5], [7], [14], [16], [17], [18], and [19]. However, the use of LESS as a minimally invasive treatment for renal tumours is under scrutiny [20]. The same applies for adrenal LESS surgery, where early in the surgeon's experience—to minimise the risks of complications—he or she should select a nononcologic case [21].

At this time, we speculate that it is unlikely that there will be any difference in terms of cancer control between LESS and conventional laparoscopic techniques. Randomised controlled trials with longer follow-up periods are awaited to address the oncologic efficacy and safety of LESS. In the meantime, careful patient selection should be employed when embarking on LESS for upper urinary tract malignancies to optimise outcomes.

Poisson regression analysis over time showed that there is a 23% non-statistically significant reduction in the risk of complications every year (IRR: 0.77; 95% CI, 0.5–1.19; p=0.242; Fig. 1). A comparison of the incidence of complication between the early phase (first 20 cases) versus the following cases of each centre was insignificant (p=0.235). Furthermore, the complexity of the procedure did not represent a predictive factor for complications.

There are few important limitations to this study. Participating centres were asked for and agreed to provide their raw data to a principal investigator, who collected them into a purpose-built datasheet. Thus, even if data had been prospectively collected by each centre, biases related to the retrospective design remain.

These data do not reflect total complications but rather complications occurring within a defined time period (90 d) after surgery. In addition, these data reflect results from different surgeons, all of them having major laparoscopic experience. However, patient-selection criteria were not standardised among centres, surgical expertise was not quantified, and different surgical techniques were applied. Ultimately, the reported figures over time do not reflect the learning curve of a single individual.

The upper-tract surgical interventions included in this series are heterogeneous. Even if they were categorised as either reconstructive or extirpative, one might argue that it would have been better to restrict the study population to patients who had a specific procedure, such as nephrectomy. Of course, the categorisation used in the analysis is somewhat artificial. However, previous studies on cumulative LESS series from single institutions have used the same categorisation, and the same categorisation has also been used in a recent multi-institutional paper looking at complications for urologic LESS [9]. Moreover, it should be noted that we also adopted a procedure classification based on a scoring system [1] and [11], where each procedure is graded according to the level of technical complexity. This parameter (ie, procedure score) has been included in the analysis.

Note that an additional trocar was applied in 40% of cases in the present series, and one might argue that this represents a major bias. In general, we embrace the concept that patient safety comes first (“do no harm”). According to current terminology [1], [22], [23], and [24], the use of an extra 2- to 3-mm trocar is still considered LESS. When the trocar is a 5 or 12mm tool, the procedure has been defined by some as “reduced port” laparoscopy. Of course, use of more than one additional trocar constitutes conversion to standard laparoscopy. Nevertheless, especially for LESS PN or for right-sided LESS RN (where liver retraction might be needed), the use of one additional port should be undertaken liberally if the surgeon is uncomfortable during LESS or in the learning curve. In a recent multi-institutional study we recently cowrote [19], use of an additional port occurred in 23% of cases, with an overall conversion rate of 20.8% (15.8% to reduced-port laparoscopy, 4% to laparoscopy, and 1% to open surgery).

Finally, one might argue that, similar to drug evaluation, any new surgical technique should be compared to the original technique before one can draw any conclusions concerning its benefits. In this analysis, no control group (ie, standard laparoscopy) was considered, and use of a control group was actually outside the scope of the present manuscript. Thus, the actual benefits of LESS compared to standard laparoscopy remain to be proven, and further clinical validation is expected.

5. Conclusions

Patient selection represents a key factor when performing LESS. Findings from our multicentre analysis suggest that malignant disease at pathology and high ASA score represent predictive factors for complications after LESS for upper urinary tract surgery. Thus, surgeons approaching LESS should start with benign diseases in low-surgical-risk patients to minimise the likelihood of postoperative complications.

Author contributions: Francesco Greco had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Study concept and design: Greco, Cindolo, Autorino.

Acquisition of data: Greco, Cindolo, Autorino, Micali.

Analysis and interpretation of data: Greco, Cindolo, Autorino.

Drafting of the manuscript: Greco, Cindolo.

Critical revision of the manuscript for important intellectual content: Greco, Cindolo, Autorino, Stein.

Statistical analysis: Fanizza.

Obtaining funding: None.

Administrative, technical, or material support: None.

Supervision: Kaouk, Fornara, Schips, Bianchi.

Other (specify): None.

Financial disclosures: I certify that all conflicts of interest, including specific financial interests and relationships and affiliations relevant to the subject matter or materials discussed in the manuscript (eg, employment/affiliation, grants or funding, consultancies, honoraria, stock ownership or options, expert testimony, royalties, or patents filed, received, or pending), are the following: None.

Funding/Support and role of the sponsor: None.

References

  • [1] R. Autorino, J.A. Cadeddu, M.M. Desai, et al. Laparoendoscopic single-site and natural orifice transluminal endoscopic surgery in urology: a critical analysis of the literature. Eur Urol. 2011;59:26-45 Abstract, Full-text, PDF, Crossref.
  • [2] J.U. Stolzenburg, P. Kallidonis, G. Hellawell, et al. Technique of laparoscopic-endoscopic single-site surgery radical nephrectomy. Eur Urol. 2009;56:644-650 Abstract, Full-text, PDF, Crossref.
  • [3] J.D. Raman, A. Bagrodia, J.A. Cadeddu. Single-incision, umbilical laparoscopic versus conventional laparoscopic nephrectomy: a comparison of perioperative outcomes and short-term measures of convalescence. Eur Urol. 2009;55:1198-1206 Abstract, Full-text, PDF, Crossref.
  • [4] D. Canes, A. Berger, M. Aron, et al. Laparo-endoscopic single site (LESS) versus standard laparoscopic left donor nephrectomy: matched-pair comparison. Eur Urol. 2010;57:95-101 Abstract, Full-text, PDF, Crossref.
  • [5] R.K. Goel, J.H. Kaouk. Single port access renal cryoablation (SPARC): a new approach. Eur Urol. 2008;53:1204-1209 Abstract, Full-text, PDF, Crossref.
  • [6] L. Cindolo, S. Gidaro, F.R. Tamburro, L. Schips. Laparo-endoscopic single-site left transperitoneal adrenalectomy. Eur Urol. 2010;57:911-914 Abstract, Full-text, PDF, Crossref.
  • [7] M.A. White, R. Autorino, G. Spana, et al. Robotic laparoendoscopic single-site radical nephrectomy: surgical technique and comparative outcomes. Eur Urol. 2011;59:815-822 Abstract, Full-text, PDF, Crossref.
  • [8] J.R. Berkowitz, M.E. Allaf. Laparoendoscopic single-site surgery: complications and how to avoid them. BJU Int. 2010;106:903-907 Crossref.
  • [9] Irwin BH, Cadeddu JA, Tracy CR, et al. Complications and conversions of upper tract urological laparoendoscopic single-site surgery (LESS): multicentre experience: results from the NOTES Working Group. BJU Int. In press. doi:10.1111/j.1464-410X.2010.09663.x.
  • [10] M. Graefen. The modified Clavien system: a plea for a standardized reporting system for surgical complications. Eur Urol. 2010;57:387-389 Abstract, Full-text, PDF, Crossref.
  • [11] B. Guillonneau, C.C. Abbou, J.D. Doublet, et al. Proposal for a “European Scoring System for Laparoscopic Operations in Urology”. Eur Urol. 2001;40:2-7 Crossref.
  • [12] D. Dindo, N. Demartines, P.A. Clavien. Classification of surgical complications: a new proposal with evaluation in a cohort of 6336 patients and results of a survey. Ann Surg. 2004;240:205-213 Crossref.
  • [13] G. Zou. A modified Poisson regression approach to prospective studies with binary data. Am J Epidemiol. 2004;159:702-706 Crossref.
  • [14] F. Greco, S. Wagner, M.R. Hoda, K. Weigand, A. Inferrera, P. Fornara. Single-portal access laparoscopic radical nephrectomy for renal cell carcinoma in transplant patients: the first experience. Eur Urol. 2011;59:1060-1064 Abstract, Full-text, PDF, Crossref.
  • [15] M.T. Gettman, W.M. White, M. Aron, et al. Where do we really stand with LESS and NOTES?. Eur Urol. 2011;59:231-234 Abstract, Full-text, PDF, Crossref.
  • [16] W.K. Han, D.S. Kim, H.G. Jeon, et al. Robot-assisted laparoendoscopic single-site surgery: partial nephrectomy for renal malignancy. Urology. 2011;77:612-616 Crossref.
  • [17] Y.H. Park, J.H. Park, C.W. Jeong, H.H. Kim. Comparison of laparoendoscopic single-site radical nephrectomy with conventional laparoscopic radical nephrectomy for localized renal-cell carcinoma. J Endourol. 2010;24:997-1003 Crossref.
  • [18] Y.H. Park, S.Y. Park, H.H. Kim. Laparoendoscopic single-site nephroureterectomy with bladder cuff excision for upper urinary tract transitional-cell carcinoma: technical details based on oncologic principles. J Endourol. 2010;24:563-566 Crossref.
  • [19] Kaouk JH, Autorino R, Kim FJ, et al. Laparoendoscopic single-site surgery in urology: worldwide multi-institutional analysis of 1076 cases. Eur Urol. In press. doi:10.1016/j.eururo.2011.06.002.
  • [20] R. Khanna, H.K. Laydner, W. Isac, R.J. Stein. Laparoendoscopic single-site surgery for renal malignancies. Expert Rev Anticancer Ther. 2010;10:1861-1863 Crossref.
  • [21] Rane A, Cindolo L, Schips L, De Sio M, Autorino R. Laparoendoscopic single site (LESS) adrenalectomy: technique and outcomes. World J Urol. In press. doi:10.1007/s00345-011-0678-z.
  • [22] G. Box, T. Averch, J. Cadeddu, et al. Nomenclature of natural orifice translumenal endoscopic surgery (NOTES) and laparoendoscopic single-site surgery (LESS) procedures in urology. J Endourol. 2008;22:2575-2581
  • [23] I.S. Gill, A.P. Advincula, M. Aron, et al. Consensus statement of the consortium for laparoendoscopic single-site surgery. Surg Endosc. 2010;24:762-768 Crossref.
  • [24] M. Aron, D. Canes, M.M. Desai, G.P. Haber, J.H. Kaouk, I.S. Gill. Transumbilical single-port laparoscopic partial nephrectomy. BJU Int. 2009;103:516-521

Footnotes

a Department of Urology and Renal Transplantation, Martin-Luther-University, Halle/Saale, Germany

b Department of Urology, “S. Pio da Pietrelcina” Hospital, Vasto (CH), Italy

c Section of Advanced Laparoscopy and Robotics, Glickman Urological and Kidney Institute, Cleveland Clinic, Cleveland, OH, USA

d Department of Urology, University of Modena, Modena, Italy

e Department of Clinical Pharmacology and Epidemiology, Consorzio Mario Negri Sud, Santa Maria Imbaro, Italy

lowast Corresponding author. Martin-Luther-University, Clinic of Urology and Renal Transplantation, Ernst-Grube-Strasse 40, 06120 Halle/Saale, Germany. Tel. +43 664 174 0323; Fax: +49 345 557 4432.

1 Both authors contributed equally to the manuscript.

Place a comment

Your comment *

max length: 5000