Laparoendoscopic single-site surgery (LESS) has been developed in an attempt to minimise the morbidity and scarring associated with surgical intervention.
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.
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
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.
Keywords: Complications, Laparoendoscopic single-site surgery, Upper urinary tract, Outcomes, Standardised criteria.
Laparoendoscopic single-site surgery (LESS) has been developed in an attempt to further reduce the morbidity and scarring associated with laparoscopic surgery . Early clinical series have demonstrated the feasibility of a broad range of LESS urologic procedures , , , , , and . Few reports have specifically looked at complications after LESS in urology . Irwin et al reported their multi-institutional experience with 125 upper-tract LESS procedures, showing a complication rate of 15.2% .
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 .
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 .
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 . 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 . 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).
3.1. 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
|Gender, no. (%):
|ASA score, no. (%):
|Comorbidities, no. (%):
|Surgical procedures, no. (%):
|Kind of procedure, no. (%):
|Use of additional ports, no. (%)||77 (40.1)|
|Kind of disease, no. (%):
|Complexity score, no. (%):**
* Data are reported as mean plus or minus SD for continuous variables and number (percentage) for categorical variables.
** See reference .
3.2. Intraoperative and postoperative characteristics
Mean operative time was 164
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.
|Complication||No. of patients||Action|
|Clavien grade 1:||4||–|
|Clavien grade 2:||22||–|
|Clavien grade 3a:||2||–|
|1||Ureteral stent placement|
|1||Angioembolisation, transfusion, and antibiotics|
|Clavien grade 3b:||2||–|
|Clavien grade 4:||1||–|
|1||Admission to stroke unit|
|Conversion to open surgery||4||–|
|Constant CO2 leakage||1||–|
|Overall complication rate||33 of 192 (17%)||–|
* Some patients had multiple complications (eg, conversion to open surgery and transfusion).
|Patients without complications (n
||Patients with complication (n
|Categoric variables, no. (%):|
|80 (50.3)||20 (60.6)||–|
|79 (49.7)||13 (39.4)||–|
|47 (29.6)||7 (21.2)||–|
|83 (52.2)||14 (42.4)||–|
|29 (18.24)||12 (36.4)||–|
|49 (30.8)||8 (24.2)||0.4|
|12 (7.6)||6 (18.2)||0.093|
|68 (42.8)||17 (51.5)||0.373|
|13 (8.2)||4 (12.1)||0.503|
|70 (44)||19 (57.6)||0.165|
|24 (15.1)||4 (12.1)||–|
|133 (83.7)||29 (87.9)||–|
|2 (1.3)||0 (0.0)||–|
|65 (40.9)||12 (36.4)||0.63|
|48 (30.2)||20 (60.6)||–|
|111 (69.8)||13 (39.4)||–|
|93 (58.5)||20 (60.6)||–|
|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.
Univariable and multivariable analyses showed that a higher ASA score (IRR: 1.4; 95% CI, 1.0–2.1; p
|IRR||LLC||ULC||p value||IRR||LLC||ULC||p value|
|Presence of comorbidity|
|Malignant disease at pathology|
|Use of additional port|
|Kind of surgery|
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
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 . LESS series in urologic literature have been reported for well-selected patients , , , , , and , even if experience with LESS RN in transplant patients has been also described .
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 .
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 , 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.  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  and . 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 , , , , , , , and . However, the use of LESS as a minimally invasive treatment for renal tumours is under scrutiny . 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 .
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
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 . Moreover, it should be noted that we also adopted a procedure classification based on a scoring system  and , 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 , , , and , the use of an extra 2- to 3-mm trocar is still considered LESS. When the trocar is a 5 or 12
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.
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.
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.
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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
Both authors contributed equally to the manuscript.
© 2011 European Association of Urology, Published by Elsevier B.V.