Comparison of laparoendoscopic single site (LESS) and conventional laparoscopic donor nephrectomy at a single institution

Authors


Correspondence: Richard E. Link, Scott Department of Urology, Baylor College of Medicine, 6620 Main Street, Suite 1325, Houston, TX 77030, USA.

e-mail: link@bcm.edu

Abstract

What's known on the subject? and What does the study add?

  • Most transplant centres harvest living donor kidneys via a conventional laparoscopic surgical approach. Laparoendoscopic single-site donor nephrectomy (LESS-DN) is a relatively novel minimally invasive approach that allows the surgery to be performed via a single incision. This technique may be advantageous in decreasing surgical morbidity and improving cosmetic outcomes, thus plausibly reducing the barriers to kidney donation.
  • The study demonstrates the safety and feasibility of LESS-DN in a large consecutive series of kidney donors. Comparative analysis between LDN and LESS-DN showed that there was a significant decrease in intra-operative blood loss and allograft warm ischaemia time in the LESS-DN group, but also a significant increase in operating time. Other peri-operative outcomes were similar between the two approaches. Evaluation of the LESS-DN cases alone revealed that, the operating times did not significantly change through the course of the series. Using this outcome as a surrogate for technical difficulty suggests a relatively shallow learning curve for LESS-DN.

Objective

  • To present a comparative analysis of peri-operative outcomes for >200 cases of conventional laparoscopic donor nephrectomy (LDN) and laparoendoscopic single site donor nephrectomy (LESS-DN).

Patients and Methods

  • From 2006 to 2011, 213 donor nephrectomies were performed by two surgeons (R.E.L and W.A.M.) at a tertiary transplant centre. The approach changed from conventional LDN to LESS-DN over the course of the series.
  • The two approaches were compared retrospectively and evaluated for differences in peri-operative outcomes.
  • Statistical significance was assessed using Student's t-test and chi-squared analysis.

Results

  • A total of 111 patients underwent LDN and 102 patients underwent LESS-DN.
  • Total operating time was significantly longer in the LESS-DN group (206.1 vs 181.9 min, P < 0.001), but LESS-DN resulted in less intra-operative blood loss (61.5 mL vs 85.9 mL, P < 0.001) and shorter warm ischaemia times (4.4 vs 5.0 min, P = 0.01).
  • There were no significant differences in analgesic requirements, subjective pain scores, length of hospital stay, postoperative graft function, or donor's postoperative glomerular filtration rate between the two approaches.
  • Complication rates were low regardless of the approach, and there were no major complications (>grade II) in the LESS-DN group.

Conclusions

  • In experienced hands, LESS-DN results in peri-operative outcomes similar to those of conventional LDN without compromising donor safety, while providing a desirable cosmetic result.
  • For surgeons familiar with LDN, transitioning to the LESS approach using this technique appears to have a relatively short learning curve.
Abbreviations
LDN

laparoscopic donor nephrectomy

LESS-DN

laparoendoscopic single site donor nephrectomy

BMI

body mass index

eGFR

estimated GFR

Introduction

Based on the US Organ Procurement and Transplantation Network data, 15,321 kidney transplants were performed in the USA in 2011, of which ∼32% involved living donors [1]. Laparoscopic donor nephrectomy (LDN) remains the ‘gold standard’ for kidney procurement from living donors at most centres and has been shown to be safe, to result in improved donor convalescence, and to yield equivalent allograft outcomes as compared with open donor nephrectomy [2, 3]. Conventional LDN requires three to four ports and an extraction site, typically through a Pfannenstiel incision.

Laparoendoscopic single site (LESS) donor nephrectomy (LESS-DN) was developed to reduce perceived barriers to renal donation, namely peri-operative morbidity and the cosmetic impact of conventional LDN. At most centres, LESS-DN is performed via a single small peri-umbilical incision, allowing partial concealment within the umbilicus. Proponents of single-site surgery maintain that cosmesis is superior to that of traditional laparoscopy, but the evidence is mostly anecdotal. A recent survey-based study of patients who underwent kidney surgery does suggest that these patients favour the scar from LESS over those from both open and laparoscopic approaches [4]. Whether a LESS approach to donor nephrectomy results in improved peri-operative outcomes remains under investigation. Likewise, the technical barriers to surgeons making the transition to LESS and the potential impact on donor safety need further study. Finally, the question of whether LESS-DN should be limited to donors without complex anatomic variations (i.e. multiple renal arteries and/or veins, increased body mass index (BMI), right kidney procurement, etc.) remains to be answered. In the present study, we report our first 102 LESS-DN cases and compare results with those of our previous cohort of 111 conventional LDN procedures, attempting to define the positive and negative impact of LESS on donor nephrectomy during the initial learning curve.

Patients and Methods

Study Population

An institutional review board-approved database was used to identify patients who underwent either LDN or LESS-DN performed by one of two surgeons between 2006 and 2011. All patients underwent a rigorous preoperative evaluation by the multidisciplinary transplant programme, including abdominopelvic CT with concomitant angiography (2008 to the present) or direct percutaneous aortography (before 2008) to define their renovascular anatomy. Left kidneys were preferentially chosen even in the setting of multiple left renal arteries unless there were compelling anatomic reasons to donate the right kidney (significant renal size discrepancy or unusually complex vascular anatomy).

Surgical Technique

The technique of conventional LDN has been previously described and recently updated [5, 6]. The extraction site was prepared through a Pfannenstiel incision before transection of the renal vessels. The rectus fascia was adequately exposed by releasing the overlying s.c. tissue. After vessel transection and placement of the kidney into a laparoscopic specimen retrieval bag, the rectus fascia was expeditiously opened in the midline and the allograft was retrieved.

Since 2010, the majority of the patients in the present series have undergone donor nephrectomy via a single-site approach. LESS-DN was performed using the GelPOINT device (Applied Medical, Rancho Santa Margarita, CA, USA) through a peri-umbilical incision. Our technique is a modification of LESS-DN as previously described [7]. We place four ports into the GelPOINT (15 mm, 12 mm and 5 mm × 2). A 5-mm Endo-Eye deflectable camera (Olympus, Center Valley, PA, USA) was used, allowing variable positioning during the procedure to minimize conflicts with the working instruments. The port configuration in the GelPOINT and the position of the instruments is shown in Fig. 1; the ‘extraction position’ allows the assistant to hold the kidney on traction during transection of the renal vessels and minimizes instrument exchanges during extraction. Extra-long non-deflectable laparoscopic instruments are used during the procedure and the renal vessels are transected individually using a laparoscopic vascular stapler. Early in our experience, an additional 6-mm port was placed in a subxiphoid location in patients with complex anatomy to help with the dissection, but we have abandoned this approach after becoming more comfortable working solely through the GelPOINT device. We do place an additional 3-mm trocar in the upper abdomen for liver retraction when extracting a right kidney.

Figure 1.

Port placement and instrument positions through the single-site device in a left LESS-DN. A, Standard 12-mm (yellow arrow) and 15-mm (red arrow) laparoscopic ports are placed through the GelPOINT device in a lateral and medial position, respectively. The remaining ports are placed in cephalad and caudad positions and are supplied with the GelPOINT device. B, Working position: the dissection is performed by the surgeon using the cephalad and lateral ports (yellow arrows); the assistant controls the camera and the retracting instrument through the medial and caudad ports, respectively (red arrows). C, Extraction position: the camera is moved to the caudad port, allowing the surgeon to use the 15-mm port for the laparoscopic specimen retrieval bag.

Outcome Analysis

Demographic and peri-operative information was identified retrospectively using clinic and hospital records. Operating time was defined as the period from the time of the skin incision to skin closure. For evaluation of the learning curve for LESS-DN, operating times were compared over the course of the series for a single surgeon (R.E.L.) with the most experience with LDN, and linear regression was performed to show trends. Warm ischaemia time was defined from the time of renal artery occlusion to perfusion of the allograft with cold preservative solution. Postoperatively, pain was controlled with a combination of oral and parenteral narcotic analgesics, which have been calculated into morphine equivalents. Pain was assessed by using a standard visual analogue pain scale; owing to the inconsistency of available data, only subjective pain scores at the time of discharge were collected for analysis. Complications were identified and graded according to the Clavien–Dindo classification [8]. The estimated (e)GFR was calculated via the modification of diet in renal disease (or MDRD) equation. Donor eGFR was calculated preoperatively and at 2 weeks postoperatively. Recipient eGFR was also calculated at 1 and 3 months postoperatively to help define allograft function. Comparative analyses were performed using an unpaired Student's t-test for continuous variables and chi-squared analysis for categorical variables, and a P value < 0.05 was considered to indicate statistical significance.

Results

A total of 213 patients were included in the analysis, of whom 111 underwent LDN and 102 underwent LESS-DN. Table 1 shows the patient demographics and preoperative characteristics. The majority of the donors were female (67.6%) and there were no significant differences in age, BMI, or preoperative renal function between the two groups. Left kidneys were extracted in 97.7% of cases; the right kidney was removed in five patients in the LESS-DN group only. Multiple arteries to the extracted kidney were present in 25.2% of the LDN group and 26.4% of the LESS-DN group.

Table 1. Patient demographics and preoperative characteristics.
 LDNLESS-DNP
No. of patients111102 
Mean (sd; range) age, years41.7 (11.0; 22.8–66.2)42.2 (10.9; 20.5–67.2)0.79
Sex, n (%)   
Male36 (32.4)33 (32.4)0.99
Female75 (67.6)69 (67.6) 
Left : Right111 : 097 : 5 
Mean (sd; range) BMI, kg/m225.8 (3.9; 19.1–33.5)25.9 (3.8; 19.2–37.8)0.92
Renal arteries, n (%)   
183 (74.8)75 (73.5)0.53
224 (21.6)24 (23.5) 
32 (1.8)3 (2.9) 
42 (1.8)0 (0) 

Peri-operative outcomes are reported in Table 2. Patients who underwent LESS-DN experienced significantly less intra-operative blood loss (61.5 mL vs 85.9 mL, P < 0.001) and shorter warm ischaemia times (4.4 vs 5.0 min, P = 0.01) as compared with patients who underwent LDN. By contrast, total operating time was significantly longer in the LESS-DN group (206.1 vs 181.9 min, P < 0.001). There were no significant differences in analgesic requirements or subjective pain scores at hospital discharge between the two approaches. There was also no difference in the donor's postoperative GFR between the two approaches. Recipient renal function at 1 and 3 months after kidney transplantation is shown in Table 3. There was no significant difference in the eGFR of the allografts regardless of the approach used for harvest.

Table 2. Peri-operative outcomes.
 Surgical techniqueP
LDNLESS-DN
Mean (sd; range) operating time, min181.9 (28.4; 114–296)206.1 (33.8; 140–362)<0.001
Mean (sd; range) estimated blood loss, mL85.9 (51.5; 20–350)61.5 (32.6; 10–250)<0.001
Mean (sd; range) warm ischaemia time, min5.0 (1.4; 3–10)4.4 (1.4; 2–9)0.01
Mean (sd; range) discharge visual analogue pain score0.8 (1.4; 0–6)1.0 (1.5; 0–7)0.31
Mean (sd; range) inpatient morphine equivalents, mg53.3 (55.2; 3–388)55.7 (38.7; 3–192)0.72
Mean (sd; range) preoperative GFR, mL/min/1.73 m298.0 (28.1; 51.2–194.8)94.6 (19.5; 59.4–184.2)0.31
Mean (sd; range) postoperative GFR, mL/min/1.73 m261.7 (19.0; 31.8–170.59)58.0 (12.1; 34.5–122.1)0.10
Mean (sd; range) change in GFR36.3 (14.9; 3.68 to 83.9 )36.6 (11.5; 15.2 to 74.6)0.88
Day of discharge, n (%)   
Postoperative day #11 (0.9)5 (4.9)0.23
Postoperative day #265 (58.6)68 (66.7) 
Postoperative day #339 (35.1)24 (23.5) 
Postoperative day #4 or later6 (5.4)5 (4.9) 
Complications, n  
Grade I1014 
Prolonged nausea/vomiting43 
Orchalgia11 
Prolonged abdominal/flank pain25 
Seroma/Wound infection1 
Gross haematuria1 
Dysuria1 
Urinary retention3 
Atypical chest pain (negative cardiac workup)2 
Grade II32 
Blood transfusion2 
Pneumonia1  
Corneal abrasion1 
Atrial fibrillation (managed medically)1 
Grade III30 
Haemorrhage from abdominal wall requiring laparoscopic re- exploration and control2 
Retroperitoneal fluid collection requiring percutaneous drainage1 
Table 3. Recipient graft function.
Follow-upMean (sd; range) postoperative creatinine concentration,mg/dLP
LDNLESS-LDN
1 month1.28 (0.53; 0.5–4.5)1.52 (1.28; 0.6–12.9)0.12
3 months1.25 (0.60; 0.7–5.5)1.34 (0.39; 0.5–2.4)0.25

The operating times for LESS-DN cases performed by a single surgeon are shown in Fig. 2. Linear regression shows little change in operating time over the course of the series, suggesting a shallow learning curve. When results were binned into groups of two, three, five or 10 cases, conclusions were identical.

Figure 2.

Scatter plot of operating times of 91 consecutive LESS-DN cases performed by a single surgeon, with a superimposed linear regression line.

The length of hospital stay was similar between the two groups; 93.7 and 90.2% of patients undergoing LDN and LESS-DN, respectively, were discharged between postoperative day 2 and 3. Five (4.9%) patients who underwent LESS-DN were discharged on postoperative day 1 compared with only one (0.9%) patient in the LDN group. There was no significant difference in the length of hospital stay between the two groups (P = 0.23)

Intra-operative complications occurred infrequently regardless of approach. There was one case of mild bleeding from the arterial stump after stapling, which was controlled with intracorporeal suturing. Before the era of routine CT angiography, a single LDN case was aborted owing to anomalous venous anatomy. This case was completed 24 h later after direct percutaneous venography. One case required a left adrenalectomy because of persistent bleeding from the adrenal surface despite manual pressure and haemostatic agents. None of the LDN cases were converted to open nephrectomy.

Fourteen patients in the LESS-DN group required an additional laparoscopic port beyond the working ports in the device. Early in our learning curve, we routinely placed an additional laparoscopic port in any patient with complex renovascular anatomy (i.e. multiple arteries), which accounted for 11 (78.6%) of the 14 patients. As we have gained experience with LESS-DN, we have abandoned this algorithm and have not needed an additional port in >60 consecutive cases. A separate subanalysis excluding these patients was performed and did not change the reported outcomes (data not shown). The remaining three cases involved additional port placement during the course of the operation to help address technical challenges. An additional four patients had a right-sided nephrectomy and we routinely used an extra 3-mm laparoscopic port for retraction of the liver in these cases.

A total of 32 postoperative complications were recorded (Table 2). The majority of the complications were categorized as grade I according to the Clavien–Dindo classification (62.5 and 87.5% of the LDN and LESS-DN groups, respectively). There were six grade II–III complications in the LDN group, including two cases of postoperative haemorrhage from the abdominal wall requiring laparoscopic re-exploration and control of the bleeding. In addition, a retroperitoneal fluid collection developed in another patient with persistent abdominal/flank discomfort and required percutaneous drainage. There were also two patients requiring postoperative blood transfusions and one patient who was successfully treated for hospital-acquired pneumonia. In the LESS-DN group, there were only two grade II complications, including a patient who developed atrial fibrillation in the postoperative period that required cardiology consultation and medical management, and a patient who sustained a corneal abrasion after extubation that required ophthalmological consultation. Notably, there were no major complications (≥grade III) in the LESS-DN group.

Discussion

Retrospective analyses of peri-operative outcomes have shown that open donor nephrectomy results in significant postoperative pain, lengthy hospital stays, and occasional untoward sequelae, including pneumothorax requiring a thoracostomy tube (7%), small bowel obstruction (2%), wound infection (4%) and incisional hernia (3.6%) [9, 10]. The laparoscopic approach (LDN) was developed as a method to harvest donor kidneys with the expectation that it would result in reduced postoperative pain, improved convalescence, and better cosmesis than the open approach, thus helping to reduce the barriers to kidney donation [5]. Indeed, the reduced morbidity associated with LDN has augmented the supply of kidneys available for transplantation [11].

Although LDN has become the standard approach for living-donor kidney harvest, the recent development of specialized single-site laparoscopic ports has prompted some centres to apply a single-site laparoscopic approach to donor nephrectomy. The interest in LESS-DN is not only attributable to the reduction of the number of incision sites, but also to other potential benefits to the donor, including reduced postoperative pain, reduced wound-related complications, improved cosmesis, and quicker convalescence. While these goals are desirable, LESS-DN must also continue to provide peri-operative outcomes and allograft kidney function equivalent to those of LDN without any sacrifice to donor safety.

In 2008, Gill et al. [12] reported the first description and results of their initial four cases of LESS-DN. Since then, there have been several retrospective single-institution series comparing LESS-DN with LDN via a matched-pair comparison, as well as a small randomized trial comparing the two approaches [13-15]. The results of the major series are sumarized in Table 4 [13-16].

Table 4. Data summary from major reports of LDN vs LESS-DN.
 Wang et al. [14]*Canes et al. [13]*Kurien et al. [15]Andonian et al. [16]*‡Present series
LDNLESS-DNLDNLESS-DNLDNLESS-DNLDNLESS-DNLDNLESS-DN
  1. *Age-matched case-controlled cohort; randomized controlled trial; LESS-DN performed via a Pfannenstiel incision; §conversion of LESS-DN is defined as placement of additional laparoscopic port sites (conversion to hybrid LDN) or transitioning to a hand-assisted laparoscopic approach (conversion to HA); NA, data not available.
N1001001718252566111102
Mean operating time, min130156239269175172117142182206
Estimated blood loss, mL979114110892841501008662
Warm ischaemia time, min4.03.83.06.15.17.15554.94.4
Allograft 3-month creatinine concentration, mg/dL1.331.311.31.5eGFR – 86.11eGFR – 88.88NANA1.251.34
Length of hospital stay, days2.02.03.53.04.53.9222.492.3
Discharge analogue pain score: scale 1–101.11.61.42.7NANA200.81.0
Morphine equivalents, mgNANA97100NANA428355.355.7
Graft failure, n000110NANA00
Complications (Intra-operative, Clavien I–II, Clavien III–IV)11 (2,5,4)14 (5,8,1)02 (0,1,1)7 (2,5,0)8 (4,4 ,0)1 (0,1,0)016 (2,13,3)16 (0,16,0)
Conversions: open, hybrid LDN or HA, n§0,00,40,00,10,00,20,00,00,00,3
Deaths0000000000

Overall, all series that included patients with a mean BMI of 25 kg/m2, demonstrated good graft function at 3 months, and discharged patients on postoperative day 2 or 3. Cosmetic outcomes have not been standardized using validated questionnaires and pain management protocols differ between institutions. For example, Wang et al. [14] reported the use of ketorolac for donors with serum creatinine concentration < 1.5 mg/dL and listed the number of pills taken per patient of two different opiates. Late in the present series, we began using sub-fascial continuous infusions of local anaesthetic using the On-Q pain catheter system (Kimberly-Clark, Dallas, TX, USA). While our initial results with this system have been encouraging, our experience is too limited to comment on outcomes compared with traditional oral and parenteral analgesic regimens.

The present series shows an increase of ∼30 min of operating time when LESS-DN is performed as compared with LDN. This finding is consistent with previously reported series, with the exception of Kurien et al [15]. Absolute operating time is a difficult outcome to compare in donor nephrectomy series given expected differences in trainee involvement and co-ordination with the recipient case. A better timepoint could have been chosen that was more reflective of the time needed to successfully complete the operation (i.e. time from skin incision to complete dissection of the renal hilum), which could be a helpful variable to investigate in future studies.

When the operating times were compared across the present series, a very shallow learning curve was seen. For a surgeon already experienced with LDN, LESS-DN case number was a relatively insignificant factor in determining operating time. This result was somewhat surprising and argues that the transition from LDN to LESS-DN may be a less difficult technical exercise than previously thought for a surgeon with experience with traditional laparoscopy.

The present study is the first to document a statistically significant decrease in warm ischaemia time with LESS-DN as compared with LDN. Whether this mean decrease of 0.5 min is of clinical significance is debatable. This finding is in contrast to the experience of Canes and Kurien [13, 15], both of whom reported significantly longer warm ischaemia times for LESS-DN, perhaps reflecting their pioneering early experience or a variation in technique. By eliminating the need to complete an incision after transection of the renal vasculature, the LESS-DN technique should be more efficient for specimen extraction. LESS-DN with a GelPOINT also minimizes the interval of desufflation after specimen extraction, which may be beneficial in tamponading venous bleeding and may explain the trend towards less intra-operative blood loss in our LESS-DN arm.

There are several technical considerations to consider when performing LESS-DN. A flexible laparoscope is helpful in providing visualization of the operating field while minimizing conflicts with the working instruments. This scope has a relatively steep learning curve, however, which can be frustrating to an inexperienced assistant. Exposure of an artery with a high aortic insertion above the renal vein can be more challenging in LESS-DN than LDN, particularly in very tall patients. The use of an extra-long Maryland dissector and crossing the hands during this step to shift the upper pole laterally and downward can be used to compensate. Although the assistant can easily retract the colon without conflicts during the hilar and upper pole dissection, his or her ability to retract during the lower retroperitoneal dissection is limited with LESS-DN.

In an environment with multiple commercially available single-site port options, we prefer the GelPOINT device for several reasons. First, the platform shifts the pivot point of the laparoscopic instruments off the abdominal wall, providing additional space between the ports to minimize conflicts. Second, traditional laparoscopic ports can be placed through the device. Our preference is to use a 12-mm port for the dominant hand and a stepped-down 15-mm port for the 5-mm camera. This 15-mm port allows rapid introduction of a 15-mm laparoscopic specimen retrieval bag and efficient extraction of the allograft (Fig. 1C). Finally, the GelPOINT's wound protector stretches and lubricates the fascial defect and allows extraction of the kidney safely from the body with the smallest possible incision. We prefer a peri-umbilical incision for two reasons: 1) the location of the port allows similar to LDN exposure and manoeuvres, and 2) the scar can be partially hidden within the umbilical fold, resulting in an excellent cosmetic result. LESS-DN using the GelPOINT has also been successfully reported through a Pfannenstiel incision, thus allowing the scar to be completely hidden under clothing [16].

Postoperative complication rates were similar between the two approaches in our series, which is consistent with previous reports (Table 2). Notably in our LESS-DN group, none of the patients experienced a major complication (≥grade III) and neither of the grade II complications were directly related to the procedure (one case of atrial fibrillation and one case of corneal abrasion). A recent worldwide multi-institutional review of single-site urological procedures reported a postoperative complication rate of 9.5%, most of which were grade I–II [17]. This finding is similar to previously reported complication rates of conventional urological laparoscopy [18-20]. While we do not expect a major disparity in complications between LDN and LESS-DN, we do intuitively suspect that a single entry site would result in fewer wound-related complications than multiple entry sites, simply owing to fewer sites of trauma with the latter approach. Moreover, a midline, peri-umbilical incision should minimize inadvertent damage to the epigastric vessels and other abdominal wall perforators, which may help prevent port site haemorrhage.

The present study has some limitations and is subject to the biases inherent to single-institution data gathered retrospectively. A prospective, randomized trial comparing LDN with LESS-DN is accruing patients at the time of this publication (http://www.clinicaltrials.gov/ct2/show/NCT01236326?term=NCT01236326&rank=1) and should help to determine whether any true differences in outcomes exist between the two approaches. Long-term follow-up of our study population was limited as the majority of donors did not routinely return to our clinic after their initial postoperative visit. As a result, the incidence of delayed complications or other late effects could not be ascertained by the present study. Moreover, long-term quality-of-life and satisfaction measures are not available and could be helpful in inferring donor preferences of the surgical approach.

In conclusion, LESS-DN is a feasible and safe approach for the procurement of living donor kidneys and appears to result in similar peri-operative outcomes to those of conventional LDN. In the present series of >100 LESS-DNs, we found that the patients experienced significantly less intra-operative blood loss, shorter allograft warm ischaemia times, and longer operating times as compared with our historical series of LDN. Single-site surgery may also help to satisfy patient desires for improved cosmesis, reduce wound-related complications, and decrease potential barriers to kidney donation; further evidence is needed to support these potential benefits. For surgeons already experienced with LDN, the technical transition to the single-site approach does not appear to have a steep learning curve.

Conflict of Interest

None declared.

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