|Year : 2022 | Volume
| Issue : 2 | Page : 225-229
Stretching the limits: Finding the standard for achieving single graft artery lumen after left laparoscopic donor nephrectomy – A retrospective cohort study
Pankaj Panwar1, Devanshu Bansal2, Ruchir Maheshwari2, Samit Chaturvedi2, Pragnesh Desai2, Anant Kumar2
1 Department of Urology, University Hospitals of North Midlands, Stoke on Trent, United Kingdom
2 Department of Urology, Renal Transplantation, Robotics and Uro-oncology, Max Hospital, Saket, New Delhi, India
|Date of Submission||08-Aug-2020|
|Date of Acceptance||28-Apr-2021|
|Date of Web Publication||30-Jun-2022|
Dr. Anant Kumar
Department of Urology, Renal Transplantation, Robotics and Uro-oncology, Max Hospital, Saket, New Delhi
Source of Support: None, Conflict of Interest: None
Context: Optimum main renal artery (RA) length before first branching needed to achieve single lumen during laparoscopic donor nephrectomy (LDN) is not known. Aims: The aim of the study is to identify optimal minimum length of RA before first branching which can be safely harvested as a single lumen in LDN. Settings and Design: This is a single institutional, retrospective study. Materials and Methods: Records of consecutive left LDNs performed at our institute from January 2016 to June 2019 were reviewed. RA length was measured from preoperative computed tomography angiogram. We clipped RA using two Hem-o-lok® and one titanium clip while maintaining constant mild upward traction. Primary outcome was to identify lowest RA length at which chances of achieving a single lumen were maximum. Secondary outcomes included minimum RA length below which single lumen could not be achieved and incidence of intraoperative vascular complications. Statistical Analyses: Receiver operator characteristic curve was plotted according to donor RA length. Likelihood ratio positive (LR+) was used to identify optimum length of RA above which chances of achieving single lumen were maximum. Results: Four hundred and eighty-eight donors with single RA underwent left LDN during study period. LR +of achieving single lumen after clipping was maximum at 10mm cutoff. Single lumen could not be achieved below 6–7 mm cutoff. There were no vascular complications or re-explorations. Conclusions: Main left RA length ≥10 mm before first branching is most likely to yield single lumen for implantation with our technique.
Keywords: Early branching, laparoscopic donor nephrectomy, minimal renal artery length, multiple renal arteries, renal transplantation
|How to cite this article:|
Panwar P, Bansal D, Maheshwari R, Chaturvedi S, Desai P, Kumar A. Stretching the limits: Finding the standard for achieving single graft artery lumen after left laparoscopic donor nephrectomy – A retrospective cohort study. Indian J Transplant 2022;16:225-9
|How to cite this URL:|
Panwar P, Bansal D, Maheshwari R, Chaturvedi S, Desai P, Kumar A. Stretching the limits: Finding the standard for achieving single graft artery lumen after left laparoscopic donor nephrectomy – A retrospective cohort study. Indian J Transplant [serial online] 2022 [cited 2022 Sep 25];16:225-9. Available from: https://www.ijtonline.in/text.asp?2022/16/2/225/349366
| Introduction|| |
Compared to multiple donor renal arteries (RAs), single RA has been found to have shorter warm and re-warm ischemia times, better 1-year graft survival as well as lower vascular and urologic complications in renal allograft recipients., Renal pedicle control to achieve optimum donor vessel length is the key step in donor nephrectomy. This becomes, especially crucial in patients with early arterial branching, defined as first branch at 15 mm from main RA origin. Selecting the opposite renal unit may not be possible in all situations, such as contralateral multiple RAs or ipsilateral nephrolithiasis. Therefore, it is important to try to achieve a single renal arterial stump without compromising donor safety.
It is important to know the distance of first branch from origin of main RA as application of clips or stapler is likely to compromise the possibility of achieving a single lumen artery if distance to first branch is less than optimal. However, there is no optimal length of RA or technique of hilar control defined in literature which will lead to single lumen anastomosis after laparoscopic donor nephrectomy (LDN). Similarly, the best instrument for vascular control (nonabsorbable polymer locking clips versus stapler) is not defined. Therefore, we performed this retrospective cohort study to evaluate our surgical technique for achieving maximum RA length during LDN and analyze our data for identifying the optimal minimum length of RA needed to achieve single lumen after RA clipping and cutting.
| Materials and Methods|| |
We performed a retrospective analysis of a prospectively maintained database of all patients undergoing donor nephrectomy and renal transplant at our center from January 2016 to June 2019. Only left-sided LDNs with single RA were chosen for uniformity. Donors with complex venous anatomy were excluded to remove confounding effect of complicated venous anatomy on technique of renal pedicle control. The primary outcome was to identify the lowest main RA length at which the chances of achieving a single lumen were maximum and that of achieving multiple lumens were minimum. The secondary outcomes included the minimum main RA length below which single lumen could not be achieved after clipping and the incidence of intraoperative vascular complications and re-exploration during LDN. The records of preoperative donor computed tomography angiogram (CTA) were evaluated to retrieve the details regarding number of RAs, vein, and ureter. Length of main RA and distance from aorta to origin of first branch are routinely measured by dedicated radiologists at our center. Length of main RA till first branching was calculated along the curve of the RA [Figure 1]. Intraoperative details regarding vascular control, intraoperative complications, and vascular reconstruction if undertaken were recorded from the operative note. The number of donors in whom a single lumen and those in whom multiple lumens could be achieved were grouped according to the length of RA before origin of first branch at 1-mm interval as calculated on the preoperative CTA.
|Figure 1: (1.1) Donor X (a) computed tomography angiogram showing early branching of left renal artery at 8.9 mm (b and c) intraoperative photographs showing clipping of renal artery with early branching and common stump of renal artery obtained after division. (1.2) Donor Y (d) computed tomography angiogram showing early branching of left renal artery (e) bench dissection showing donor renal artery with early branching|
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All LDNs were performed by a single experienced laparoscopic and transplant surgeon. All left LDNs were done transperitoneally after placing the patient in right lateral decubitus position. Two 12-mm ports and two 5-mm ports were used [Figure 2]. Pneumoperitoneum was created after placing 12 mm Excel (Ethicon Inc., Somerville, US) port under direct vision at camera port site. Harmonic® scalpel (JNJ Inc., New Burnswick, US) was used to mobilize left colon and perform dissection at upper pole and near adrenal gland. Hilar vessels were dissected using hook monopolar cautery. Adequate space for clip application was ensured around both RA and vein using right-angled forceps. Adrenal vein and lumbar vein if present were clipped doubly with small nonabsorbable Polymer Locking Clips (Weck® Hem-o-lok®-Teleflex Inc., Pennsylvania, US) and cut. After complete mobilization of kidney all around, the gonadal vein was doubly clipped and cut. A Pfannenstiel incision was given. A single clip was applied at distal end of ureter, which was cut and good diuresis was observed. Slight traction was placed at the hilum using left-hand instrument below and the assistant instrument above. Care was taken to limit the traction on RA till the renal vein became taut so as to prevent any arterial intimal tear. This straightens the RA. Using adequate traction as described above, the RA was straightened out and two Hem-o-Lok® clips were applied proximally on artery at its origin. A single 400 LT titanium clip (LIGACLIP®-Ethicon, US) proximal to polymer clips was applied at the junction of aorta and RA. The height of each Hem-o-lok® clip was 1.5 mm and of titanium clip was 1 mm. RA was cut distal to second Hem-o-Lok® clip while leaving a small stump beyond the clip (approximate height of one closed Hem-o-lok® clip) [Figure 1]. No attempt was made to save the accessory artery or early branch to compromise donor safety. If a single lumen could not be achieved safely, two lumens were accepted. Renal vein was then clipped and cut, and kidney was quickly retrieved through Pfannenstiel incision and placed in ice slush. RA was identified and cannulated and flushed with Histidine-Tryptophan-Ketoglutarate solution. Bench preparation was done at the recipient bedside and artery length reassessed for possible single lumen anastomosis. In cases the length was not sufficient after refreshening, an end-to-side or side-to-side anastomosis was created or two separate implantations were done on operating surgeon's discretion. Key points of our technique include the use of two Hem-o-lok and one titanium clip instead of stapler, skeletonization of RA at its origin so that adequate stretch is not hindered by periarterial lymphatics, complete division of ureter before clipping the renal vessels (it enables better traction on vessels allowing preservation of longer vessel length after clipping), applying traction on RA till renal vein become taut (to prevent excessive arterial stretch and intimal tearing while providing additional length for clipping).
|Figure 2: Line diagram showing port position for left laparoscopic donor nephrectomy|
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Postoperatively, all donors were mobilized the next day. Per urethral catheter was removed on day 1 and drain was removed on day 2 to 3. All donors were discharged by day 4. Analgesia was given with intravenous paracetamol and tramadol.
To identify the optimal length of the RA before the first branch, the number of donors in whom a single lumen and those in whom multiple lumens were achieved was plotted according to 1-mm incremental main RA length on a receiver operator characteristic (ROC) curve. The likelihood ratio positive (LR+) was used to identify the optimum length of main RA above which the chances of achieving a single lumen were maximum and the chances of multiple lumens were minimal. Statistical analysis was done using Microsoft® Excel version 16.16.23 (2018).
Declaration of patient consent
The authors certify that patient consent has been taken for participation in the study and for publication of clinical details and images. Patients understand that the names, initials would not be published, and all standard protocols will be followed to conceal their identity.
In view of retrospective nature of the study, Max Hospital ethical review board committee approval was not required. The procedure was carried out in accordance with the Declaration of Helsinki and International Council for Harmonization-Good Clinical Practice (ICH-GCP). The study was performed according to the guidelines in Declaration of Helsinki.
| Results|| |
A total of 602 left-sided LDNs were performed at our center during the study period. Of these, 104 kidneys had multiple vessels and were excluded from analysis. Another 10 patients were excluded due to complex venous anatomy (4 with retroaortic renal vein, 3 circumaortic renal vein, 2 multiple renal veins, and 1 double inferior vena cava and anomalous origin of left renal vein) for this study to remove any technical bias. Four eighty-eight patients had a single main RA and were included in final analysis. 177 (36.3%) donors had early branching of main RA. The number of donors with early branching in whom single lumen was achieved is detailed in [Table 1]. The ROC curve was plotted as shown in [Figure 3]. The area under curve of the ROC curve was 0.98, suggestive of excellent discriminative value of main RA length before first branching to identify achievement of single lumen versus multiple lumens after clipping. The highest LR + was achieved at the cutoff of 10 mm.
|Figure 3: Receiver operator characteristic curve showing distribution of donors in whom single and those in whom multiple lumens were achieved plotted according to the length of renal artery before origin of first branch at 1-mm interval as measured on preoperative computed tomography angiogram|
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|Table 1: Distribution of donors with early branching according to status of renal artery lumen after clipping|
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The lowest main RA length cutoff below which single lumen could not be achieved was 6–6.9 mm. Single lumen could be achieved in 4 out of 35 patients (11.4%) with RA length between 6 and 6.9 mm, 41 of 45 patients (97.6%) with the cutoff of 7–7.9 mm, 2 of 3 patients (66.7%) with RA length of 8–8.9 mm, and 1 of 3 patients (33.3%) with the length cutoff of 9–9.9 mm [Table 1]. There were no incidences of hemorrhage due to clip failure. There were no donor re-explorations.
| Discussion|| |
LDN is the current method of choice for procurement of donor kidneys. However, vascular control during LDN by either clips or staples leads to significantly greater loss of RA length compared to open nephrectomy. In cases with early branching of RA (defined as first branch at 15 mm from main RA origin), LDN may fail to retrieve a single RA for implantation. However, due to established advantages of minimally invasive surgery, every attempt should be made to achieve a single vessel in LDN itself before resorting to open conversion without compromising donor safety.
Donor kidneys with multiple RAs have traditionally been found to have worse outcomes compared to single artery in terms of vascular and urologic complications in the recipient. In a meta-analysis by Afriansyah et al., the authors found that donors with multiple RAs had a significantly longer cold ischemia time compared to donors with single artery. Incidence of vascular complications (2.6% vs. 1.3%, P < 0.001), ureteral complications (3.5% vs. 2.7%, P = 0.03), and 1-year graft loss (1-year graft survival 93% vs. 95.3%, P = 0.016) were also higher in the kidneys with multiple arteries. Reconstruction and implantation of graft with multiple arteries are also a technically challenging procedure., Therefore, every attempt should be made to achieve a single RA at the time of LDN. Variations in surgical technique and instruments used for arterial clipping may help in achieving a single RA in patients with early branching.
Single RA for implantation may become especially important in recipients with calcified iliac vessels, history of previous failed transplants with previous grafts in situ, or obese recipients with deep working space. Alternative plans for implantation or use of other side or alternate donor may be required, in case, it is expected that achievement of single RA will not be feasible. However, the optimal length of main RA predictive of single vessel at implantation is not defined in literature. To the best of our knowledge, only one previous publication has addressed this issue. In a series of 287 consecutive LDNs, Iype et al. found that a main RA length of < 16 mm on the left and 26 mm on the right side was unlikely to yield a single vessel for implantation. Renal arterial length was measured by magnetic renal angiography in majority (97%) cases. The authors also found that the presence of complex venous anatomy was significantly associated with the possibility of obtaining multiple arteries after hilar control. A laparoscopic stapling device (Endopath ETS-Fle× 45; Ethicon Inc. Somerville, US) was used for arterial control in all cases.
The best instrument (clips versus stapler) for hilar control is debatable. The safety of Hem-o-lok® clips was rendered doubtful after a survey reported two mortalities due to late clip malfunction, and a black box warning was issued against the use of Hem-o-lok® clips in LDN., However, this survey was retrospective and did not elaborate on two similar donor mortalities due to stapler malfunction. Many transplant surgeons in Asia and Europe continue to use Hem-o-lok® clips in LDN, and their efficacy and safety have been previously published.,, Clips provide several advantages over staplers including longer residual RA length,, convenience and flexibility in application, and significantly lower cost, while risk of severe hemorrhage is not increased. The device failure rate is also similar. Previous studies also suggest that leak-point pressure of clips is higher than staples and that either Hem-o-lok® or titanium clips are unlikely to slip from the arterial stump at physiological pressures. We routinely use Hem-o-lok® clips even in nondonor nephrectomies and have found them to be safe and effective in our practice.
We evaluated all our donors with a preoperative CTA to assess the vascular anatomy. CTA is the investigation of choice among noninvasive imaging modalities to evaluate donor vessels, with accuracy of 95%–100%. Renal arterial and venous anatomy are evaluated primarily on arterial phase images. The length of the main RA is usually determined by measuring the curvilinear distance from the ostium of the RA to the first renal branch using postprocessing techniques. The tortuosity of main RA is usually only modest, with Davis et al. stating the mean arterial tortuosity of 1.1 ± 0.2 in axial and 1.2 ± 0.2 in coronal planes on the left side. Another important consideration is interobserver agreement for RA length measurement, which usually ranges from 80% to 93%.,
We believe that the use of two Hem-o-lok® and one titanium clip provides longer vessel and is equally safe for the donor as compared to staplers. The key points to ensure safe clipping of RA include adequate dissection of the renal vessels, visualization of the knob of the Hem-o-lok® clip posterior to the vessel before clipping, hearing distinct click of locking sound of the clip, using two types of clips (nonabsorbable polymer locking and metal) for RA control, and leaving a small gap between the site of RA division and the distal clip. Previously, some authors have raised concerns that undue stretch of RA during clipping may lead to intimal tears and consequent arterial wall dissection. However, we believe that in cases with early branching, our technique of controlled traction of RA keeping the renal vein as a guide provides the best chance of achieving a single arterial stump for implantation without causing any arterial intimal injury. We did not encounter any incidence of arterial intimal injury. Our technique is safe and reproducible.
Limitations of the study
There are few limitations to our study. We could not confirm the CTA measurements in vivo as it was a retrospective study. There is also a small risk of interobserver variation in RA length measurement as the CTA was reported by a team of radiologists in our study. There was limited number of patients at some cutoff RA lengths (such as 8 mm and 9 mm). We could safely achieve a single lumen in 97.6% donors with a RA length cutoff of 7 mm, however, the smaller number of donors at the above cutoffs could have shifted our threshold to 10 mm. However, all our medical records are computerized, and therefore, there is minimal data loss over the years. The radiologists are blinded to the surgical outcome, which reduces measurement bias.
We believe that a prior knowledge of the minimum main RA length above which single lumen is likely to be achieved, as evaluated from our study, is extremely important in guiding preoperative planning.
| Conclusions|| |
To conclude, our study shows that with a controlled traction of renal hilum using our technique and careful application of two Hem-o-lok® and a metal clip in tandem, the chances of achieving single lumen artery are maximum with the main renal arterial length of 10 mm or higher, without compromising graft quality and donor safety. Main renal arterial length <7 mm before origin of the first branch is unlikely to yield a single lumen for implantation during LDN. Such cases should be attempted only after having good experience in doing LDN.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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