Kidney transplant is the treatment of choice for end-stage renal disease [1]. One of the critical aspects of a successful kidney transplant is vascular anastomosis, ensuring optimal perfusion of the graft while minimizing complications such as thrombosis, stenosis, or anastomotic leaks. Transplant surgeons use different techniques for arterial and venous anastomoses in the recipients. In 1902, Carrel described a 3-point anastomosis technique for allograft arterial anastomosis [2]. Since then, others have described variants using 2-point anastomosis, 1-knot techniques, 4-quadrant techniques, corner-saving techniques, nonsuture techniques, and other methods for vascular anastomoses in kidney transplant [3]-[7]. Most of these techniques were designed to reduce anastomotic and ischemic time while providing good patency, especially in the case of arterial anastomoses. The Reverse Spatulated Hybrid Technique (RSHT) is a vascular anastomosis approach developed at our center for living-donor kidney transplantation. It combines reverse spatulation to optimize luminal geometry with a hybrid suturing strategy designed to facilitate a controlled, wide anastomosis while maintaining a favorable graft lie. This study describes the RSHT and evaluates its clinical outcomes in renal transplantation.

A single-center observational retrospective study involving a dedicated transplant team. During the study period (October 2024 to February 2025), a total of 101 renal transplants were performed.

This is the standard technique followed by the team for an end-to-end anastomosis with the internal iliac artery since 2010, with over 3000 transplants done. This technique is not followed for end-to-side anastomosis.

A total of 86 kidney transplant recipients were included in the final analysis, based on predefined inclusion criteria.

Mean age of recipients was 36 ± 13.2 (9 - 66 years). 64 patients were male (74.42%), and 22 were female (25.58%).

82 (95.35%) of the donor nephrectomies were done laparoscopically and 4 (4.65%) by open surgery.

Mean kidney warm and cold ischemia time was 3.2 (1 - 8 minutes) and 75.2 (49 - 116 minutes).

Mean arterial and venous anastomotic time was 15.51 (9 - 32 minutes) and 12.38 (7 - 26 minutes).

All the graft renal arteries were anastomosed to the internal iliac artery, of which 84 (97.6%) were to the right and 2 (2.4%) to the left. All vein anastomosis was done to the external iliac vein.

No vascular complications were reported in the early postoperative period. Measuring the velocity of blood flow at the anastomotic sites by color Doppler ultrasonography on days 1, 4, and 30 after the transplant showed no evidence of arterial/ venous thrombosis or stenosis in any of the patients. During a mean follow-up of 2.5 (2 - 3 months), the mean serum creatinine level on the 1, 3, 30 and 60 - 90 days after the operation was 2.87 (0.5 - 9.2 mg/dL), 1.3 (0.5 - 3.8 mg/dL), 1.2 (0.5 - 4.4 mg/dL), 1.2 (0.5 - 4.6 mg/dL), respectively.

No delayed graft function was noted (defined as a persistence of a serum creatinine level of >4 mg/dL beyond the third day after transplant and necessity of at least one dialysis session within the 7 days post-transplant).

There were two mortalities; one case was attributed to septic shock secondary to left-sided cavitary pneumonia on POD-35, and the second case was due to cardiovascular failure on POD-136. Both had a functioning graft with maintained blood flows, proven by USG graft doppler done during their admission.

We did not encounter any vascular complications like renal artery/ vein thrombosis or stenosis. However, no contrast imaging was permissible because of the new kidney in place. The USG Doppler, as a noninvasive tool for documenting graft blood flow, is preferable.

The introduction of the Carrel patch technique for end-to-end anastomosis of allograft arteries in 1902 marked a significant advancement in transplant surgery [2].

Many transplant surgeons presented their own technique for vascular anastomosis and made efforts to reduce ischemia time and risk of transplant artery stenosis, both of which can lead to allograft dysfunction [8]. Allograft arterial stenosis should be suspected in any recipient who presents with new onset or severe hypertension refractory to medical therapy, unexplained graft dysfunction, and a new audible bruit over the graft.

There are several techniques to do this anastomosis, and each one has its own merits and demerits. The type of anastomosis chosen by the surgeon depends on the mentor, the training received at their institution, and personal preference.

Since the RSHT used at our center is technically complex and associated with a longer learning curve than a conventional end-to-end anastomosis. This complexity is mainly related to two specific steps: the main point in RSHT is visualizing the lie of both the renal artery (RA) and the internal iliac artery (IIA), and precisely spatulating both vessels in reverse direction; lie and spatulation are visual assessments made beforehand and are the key learning steps in RSHT. The first suture is taken at the 6 o’clock position on both vessels, and the determination of this point and precise suturing is another key step. With both these maneuvers, we are able to create the widest possible anastomosis between RA and IIA and also to maintain the final lie of the graft without kinking the anastomosis. The skill is transferred by repeated exposure of the residents, fellows, and post-graduate students to the same technique being done by the same surgeon over and over again.

In the iliac fossa, the kidney is at a right angle to the iliac artery. As the graft kidney falls in the iliac fossa as its final resting place, the RSHT normalizes the kink formed with the arteries by reducing the angle and thus maintain a smooth linear direction with the anatomical direction of the internal iliac which is medio-obliquely. This approach minimizes turbulence, enhances endothelial alignment, and lowers the risk of vascular kinking, stenosis, or thrombosis, leading to improved graft perfusion and function. In our series, mean arterial anastomosis time was 15.5 minutes, which is within the range reported for conventional end-to-end anastomosis techniques in open and minimally invasive kidney transplantation, where arterial anastomosis times of roughly 12 - 20 minutes are commonly described.

From our observation, it has been shown that this alternative vascular anastomotic technique is safe, with a satisfactory outcome of kidney transplant compared to the conventional technique for a kidney transplant. We had no cases of vascular complications in the early postoperative period in our patients. We did not encounter any case of renal artery or venous thrombosis, or any allograft arterial stenosis. In the era of minimally invasive techniques, for kidney transplantation, including robotic-assisted kidney transplantation, the main challenge is to perform a quality vascular anastomosis in a restricted workspace. The same technique was performed by the same team in a minimally invasive approach. Our center has performed more than 3000 kidney transplants since 2010, and in this broader experience, the reverse spatulated hybrid technique has been associated with an extremely low incidence of clinically significant TRAS, supporting its patency and safety profile.

Zomorrodi etal. compared techniques 02 techniques. In 1 group, they used a 2-corner continuous suture technique, and in the other, they used a combined suture technique (two-thirds of the artery diameter with continuous suture and one-third with interrupted sutures). And they determined that factors like gentle tissue handling and adequate vessel diameter are more critical in preventing transplant artery stenosis than the suturing technique itself [9].

The majority of authors presented techniques’ variation according to the way of suturing (number of knots, corner saving), while others used clips and staplers. In 1996, Mital etal. performed arterial and venous anastomoses in kidney recipients using four stay sutures and vascular clips, completing each anastomosis in 8 minutes, and concluded that it is a safe, easy, and rapid method of renal vascular anastomosis. Jones further improved this by introducing a sutureless method with clips, reducing the ischemic period by 51% in comparison with the conventional running suture technique [10]. Ye etal. performed an end-to-end arterial anastomosis with titanium ring pin staplers in 36 kidney recipients [6].

Haberal etal. performed arterial anastomosis of transplanted kidneys in 183 recipients using a corner-saving approach. One patient had a renal arterial stenosis. The conclusion was that this approach lowers the incidence of vascular complications and is a simple and safe way to perform arterial anastomosis [4].

In 386 kidney patients, Simforoosh etal. reported the outcomes of vascular anastomosis using the 1-suture, 1-knot approach. No vascular complications were reported in the early postoperative period. The technique was safe, time-saving, and especially valuable in obese patients and recipients with deep iliac fossa [7].

In the minimally invasive era, and particularly in robot-assisted kidney transplantation (RAKT), the main technical challenge remains achieving a high-quality vascular anastomosis within a constrained workspace while limiting warm ischaemia. Large contemporary European experiences and comparative series suggest that RAKT can be performed safely with favourable graft outcomes in selected recipients, underscoring the need for standardised, reproducible anastomotic strategies that combine efficiency with precision [11][12]. In addition, complex vascular anatomy is increasingly addressed in robotic programmes; ERUS data and subsequent comparative work indicate that RAKT using grafts with multiple vessels is feasible and often incorporates extracorporeal vascular reconstruction prior to implantation [13][14].

The main limitation of the present study is its single-centre, retrospective observational design without a control group and with short follow-up. While a randomised trial would theoretically provide the highest level of evidence, such trials comparing surgical anastomotic techniques are unlikely to be feasible in routine transplantation; therefore, evidence will most realistically accumulate through comparative cohort studies and multicentre registries. Longer follow-up with standardised imaging surveillance is required to assess late events such as transplant renal artery stenosis, anastomotic aneurysm/pseudoaneurysm, and progressive intimal hyperplasia.

The RSHT offers optimal anastomotic geometry, reducing turbulence and optimizing vascular flow dynamics in renal transplantation. This technique, although complicated, will have a longer learning curve, but we feel this technique minimizes vascular complications and demonstrates excellent patency rates. This study is limited by its short duration and single-center design. Further multicentric studies with longer follow-up periods are warranted to more accurately evaluate the clinical relevance and long-term outcomes of the RSHT in renal transplantation.

This retrospective analysis used routinely collected clinical data that were anonymised prior to analysis. The work was conducted in accordance with institutional policies and the Declaration of Helsinki. Written informed consent was obtained for the publication of identifiable intraoperative images, where applicable.