Bipolar electrocautery hemostasis in sutureless laparoscopic partial nephrectomy for exophytic small renal masses under zero-ischemia: a retrospective single-center experience

Abstract

Background

The rising detection of small renal masses (SRMs) has heightened the demand for minimally invasive, nephron-sparing surgical strategies. Sutureless laparoscopic partial nephrectomy (LPN) without renal artery clamping avoids ischemia-reperfusion injury (IRI) and preserves renal function, but achieving effective hemostasis is challenging. Bipolar electrocautery can offer reliable hemostasis via localized thermal coagulation, potentially enabling sutureless reconstruction. This retrospective study investigated the feasibility and safety of bipolar electrocautery hemostasis for sutureless LPN for exophytic SRMs without renal artery clamping.

Methods

The study included 66 patients who underwent LPN without renal artery clamping for exophytic SRMs between August 2016 and April 2023. Patients were assigned to the suture group (n=42) or the sutureless group (n=24) based on intraoperative hemostatic strategy: barbed suture repair versus bipolar electrocautery. Baseline characteristics, perioperative data, and postoperative outcomes were compared. Generalized linear models (GLM) were used to perform multivariable adjustment for potential confounders including maximum tumor diameter, preoperative hemoglobin (Hb), serum creatinine (SCr), and glomerular filtration rate (GFR).

Results

All surgical procedures were performed laparoscopically without renal artery clamping. Baseline characteristics were generally comparable between groups. Within-group analysis showed significant postoperative decreases in Hb and GFR in both groups (P<0.05), while SCr increased significantly only in the suture group (P<0.05). After multivariable adjustment, the sutureless group was associated with shorter operative time (100.82 vs. 116.26 min, P=0.04), lower postoperative SCr (69.10 vs. 75.81 µmol/L, P=0.04), higher preserved postoperative GFR (47.61 vs. 45.25 mL/min, P<0.001), and a smaller reduction in GFR (2.97 vs. 5.32 mL/min, P<0.001). However, the sutureless group was associated with higher intraoperative blood loss (154.28 vs. 89.59 mL, P=0.003). Other perioperative outcomes were comparable between groups. All surgical margins were negative, and no short-term tumor recurrence was observed in either group.

Conclusions

In selected patients with exophytic SRMs, bipolar electrocautery hemostasis during sutureless LPN performed under zero-ischemia may be feasible and is associated with a shorter operative time, a smaller early postoperative decline in renal function, and no increase in short-term complications. However, this non-randomized retrospective study has inherent limitations, such as potential temporal bias from the later introduction of the sutureless technique. These findings are hypothesis-generating and require confirmation in larger prospective randomized controlled studies.

Highlight box.

Key findings

• In this retrospective study, sutureless laparoscopic partial nephrectomy (LPN) performed with bipolar electrocautery under zero-ischemia conditions may be feasible for selected exophytic small renal masses (SRMs).

What is known and what is new?

• Renal artery clamping has been widely reported to induce ischemia-reperfusion injury (IRI), and suturing may contribute to parenchymal damage.

• This study suggests that bipolar electrocautery may provide safe and effective sutureless hemostasis during off-clamp LPN for selected exophytic SRMs, thereby potentially avoiding IRI and reducing parenchymal trauma. Nonetheless, the findings are limited by the study design.

What is the implication, and what should change now?

• The application of bipolar electrocautery hemostasis in sutureless LPN for appropriately selected exophytic SRMs performed under zero-ischemia conditions may be considered. However, given that this investigation is retrospective and single-center, larger multicenter prospective trials are required to further evaluate the long-term safety and efficacy of this approach before it can be widely implemented.

Introduction

With the advancement of imaging techniques and increased public health awareness, the detection rate of small renal masses (SRMs) has been rising annually (1,2). Laparoscopic partial nephrectomy (LPN) is now widely accepted as the standard of care for SRMs due to its benefits, including reduced trauma, quicker convalescence, and significant advantages in nephron-sparing (3,4). Conventional LPN typically requires renal artery clamping and renorrhaphy for parenchymal reconstruction. However, renal artery clamping inevitably leads to ischemia-reperfusion injury (IRI), the severity of which is mainly dependent on the warm ischemia time (WIT) (5). Remnant kidney reconstruction using suture-based renorrhaphy is associated with potential nephron loss as well as renal vascular complications, such as pseudoaneurysm formation and arteriovenous fistula development (6,7). The general goal of surgical intervention is to achieve the “trifecta”: negative surgical margins, minimal renal function loss, and absence of postoperative complications (8). Contemporary management of SRMs increasingly emphasizes renal function preservation rather than oncologic control alone. Regarding functional outcomes, main determinants include WIT, the volume of preserved renal parenchyma, and the reconstruction of the residual renal parenchyma (9). However, compared with WIT, minimization of parenchymal mass loss during resection and reconstruction represents the most important controllable aspect of long-term postoperative renal function preservation (10). Therefore, optimized strategies for residual renal parenchymal reconstruction are of great clinical significance.

Driven by the ongoing progress in minimally invasive procedures, a range of innovative sutureless hemostatic techniques using various hemostatic materials and surgical equipment rather than traditional suturing have been explored in LPN. Notably, sutureless hemostatic approaches may contribute to preserving renal function and minimizing suture-related complications, while potentially shortening operative time by avoiding renal suturing (11). However, these findings remain somewhat controversial in the literature. Among these emerging hemostatic alternatives, bipolar electrocautery has gained particular attention owing to its ease of operation and excellent hemostatic efficacy. Hemostasis with bipolar electrocautery is achieved through localized heat-induced coagulation, leading to the denaturation of tissue proteins and subsequent vessel occlusion (12). Given their relatively superficial location that tends to cause limited local injury during tumor excision, exophytic SRMs may be theoretically suitable for sutureless hemostasis. The application of bipolar electrocautery might help realize this goal, potentially reducing renal impairment related to suture-based reconstruction and possibly simplifying surgical procedures. However, there are limited reports specifically evaluating the safety and feasibility of bipolar electrocautery as a potential sutureless hemostatic modality for exophytic SRMs.

On this basis, this retrospective study evaluated the feasibility and safety of bipolar electrocautery-assisted sutureless LPN for selected exophytic SRMs without renal artery clamping. The primary hypothesis was that this technique would be feasible, and may help shorten operative time while preserving renal function, compared with conventional barbed-suture renorrhaphy. We present this article in accordance with the STROBE reporting checklist (available at https://tau.amegroups.com/article/view/10.21037/tau-2026-0250/rc).

Methods

Patients

This retrospective study reviewed all patients who underwent minimally invasive surgery for exophytic SRMs at the Department of Nephrology, First Affiliated Hospital of Army Medical University, from August 2016 to April 2023. Our institution initially commenced LPN using sutures without renal artery clamping in August 2016 and progressively optimized the technique. Based on accumulated experience, we introduced and selectively applied the sutureless bipolar electrocautery hemostatic technique in LPN without renal artery clamping. Beginning in December 2018, the sutureless bipolar electrocautery technique was employed only when intra-operative assessment confirmed that the diameter of the tumor resection bed was ≤3 cm, the collecting system was not entered, and visible arterial bleeding >3 mm was absent after tumor excision. Tumors that did not meet all of these criteria were reconstructed with barbed sutures and were classified in the suture group. The inclusion period for the suture group in the comparative analysis spanned August 2016 to April 2023, and the sutureless group encompassed cases from December 2018 to April 2023. Potential selection bias and temporal bias were present due to the later introduction of the sutureless technique. This study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the Ethics Committee of the First Affiliated Hospital of Army Medical University [(B)KY2024153]. The Ethics Committee waived the patients’ informed consent due to the retrospective nature of the study.

Inclusion and exclusion criteria

Inclusion criteria were: (I) a single renal tumor on preoperative imaging; (II) exophytic growth of the tumor, located peripherally, without invasion of the collecting system, and ≤5 cm in diameter; (III) LPN via a retroperitoneal approach without renal artery clamping; (IV) no evidence of local or distant metastasis preoperatively; and (V) normal contralateral kidney function preoperatively. Exclusion criteria were: (I) solitary kidney; (II) pre-existing kidney disease, urinary tract obstruction, or other renal disorders; (III) history of systemic diseases significantly affecting renal function, such as long-standing hypertension or diabetes mellitus (duration >10 years); and (IV) coexistence of other malignant tumors.

Data collection

Clinical data, imaging findings, laboratory results, and postoperative pathological outcomes were collected from all eligible patients. Patients were divided into two groups based on the intraoperative hemostasis method: the suture group (wound closure with barbed sutures) and the sutureless group (bipolar electrocautery hemostasis for the wound bed). Preoperatively, the R.E.N.A.L. Nephrometry Score (13), a standardized nephrometry scoring system, was used to evaluate surgical complexity. Split glomerular filtration rate (GFR) was determined preoperatively and postoperatively using emission computed tomography (ECT). Preoperative laboratory data and GFR of the affected kidney as determined by ECT were obtained from examinations performed during the preoperative preparation period. Postoperative laboratory parameters were collected within 3–7 days after surgery. Postoperative GFR of the affected kidney was assessed by ECT approximately 3 months after operation. Surgical outcomes of all patients were followed up for about 6 months postoperatively using computed tomography (CT) examinations. Due to the high proportion of benign cases, the surgical primary endpoint was limited to margin status and short-term recurrence. No missing data were observed for the main variables.

Surgical techniques

All procedures were conducted by a single surgical team with substantial expertise and experience. Under general anesthesia, the patients were positioned in the lateral decubitus position on the healthy side, followed by nephron-sparing surgery on the affected side via a retroperitoneal approach. A transverse incision of approximately 1.5–2.0 cm was made below the twelfth rib along the posterior axillary line to create the retroperitoneal space through blunt dissection with vascular clamps. A homemade balloon dilator was inserted and inflated with roughly 300–400 mL of air to achieve expansion. Subsequently, small incisions were performed, guided by the index finger, at two sites: 2.0 cm above the iliac crest along the midaxillary line and 1.0–2.0 cm below the costal arch along the anterior axillary line, into which the corresponding trocars (e.g., 10 or 5 mm) of the specified sizes were inserted to establish the operative channels (Figure 1). The retroperitoneal fat was dissected to identify the psoas major muscle, perirenal fascia, and peritoneal reflection. The Gerota’s fascia and perirenal fat were opened to reveal the kidney and tumor. The renal hilum vessels were carefully mobilized. The renal artery was identified but not clamped to facilitate surgical control. The renal parenchyma around the tumor was marked using monopolar coagulation. The tumor and surrounding tissue within 3.0–5.0 mm of the tumor margin were resected en bloc. During resection, when larger caliber vessels were encountered, hemolok clips were applied for ligation to ensure hemostasis. Beyond addressing larger vessels, hemostasis of the remaining wound bed was achieved through two distinct overarching strategies: in the sutureless group, meticulous hemostasis was obtained primarily using bipolar electrocautery (Figure 2), whereas in the suture group, hemostasis was secured with 3-0 barbed sutures.

Figure 1.

Diagrammatic representation of the port placement technique in retroperitoneal laparoscopic partial nephrectomy. (A) Localization of surface anatomical landmarks, and retroperitoneal space creation using a self-made balloon dilation method. (B) Close-up view demonstrating the successful establishment of the three working channels required for retroperitoneal laparoscopic surgery.

Figure 2.

Sutureless hemostasis technique using bipolar electrocautery in laparoscopic partial nephrectomy. (A) Intraoperative appearance of the renal wound after tumor resection. (B,C) Demonstration of bipolar electrocautery for hemostasis with concurrent suction. (D) Postoperative morphology of the renal wound with stable eschar formation.

Specifically, in the sutureless group, the ERBE VIO 300S electrosurgical unit was used with “Bipolar Coagulation” mode and power setting of 40–50 W. After tumor resection, visible bleeding points were coagulated point-by-point. If slow oozing persisted after 2–3 minutes of observation, additional electrocautery was applied, supplemented with hemostatic gauze or powder if necessary. In both groups, intraoperative transfusion was administered when estimated blood loss exceeded 400 mL with hemodynamic instability. In the sutureless group, if the collecting system was found to be open during the procedure, the hemostatic strategy was converted to suture repair immediately. In both groups, if uncontrollable, extensive bleeding from the resection bed occurred, renal artery clamping was performed promptly to ensure patient safety. The tumor specimen was extracted and sent for pathological analysis. Once hemostasis was confirmed and no active bleeding was observed, a drainage tube was placed, and the operation was completed.

Statistical analysis

Statistical analysis was performed using SPSS 26.0 software. Categorical variables were presented as frequencies and percentages (%), and compared using the Chi-squared test (χ²). Normally distributed continuous variables were expressed as mean ± standard deviation, with intergroup comparisons using the independent samples t-test and within-group comparisons using the paired t-test. Non-normally distributed continuous variables were described as median (interquartile range) [M (P25, P75)], and non-parametric tests (Mann-Whitney U test or Wilcoxon signed-rank test) were applied for analysis. Generalized linear models (GLM) were used to adjust for confounding factors. The model specification was selected according to the distribution of outcome variables. Gamma distribution with log-link was used for non-normal data, and normal distribution with identity-link for normal data. Covariate adjustment varied by outcome. P<0.05 was considered statistically significant.

Results

Baseline characteristics of the two groups

A total of 66 patients were enrolled in this study, comprising 42 patients in the suture group and 24 in the sutureless group. All patients successfully underwent the procedure laparoscopically without conversion to renal artery clamping. In the sutureless group, no case required conversion to suturing. The mean ages were 50.17±9.82 and 49.42±8.95 years for the two groups, respectively. The median R.E.N.A.L. scores were both 5. The maximum tumor diameters were 3.25 and 2.50 cm, and the preoperative GFR of the affected kidney was 50.24±8.53 and 51.15±6.22 mL/min, respectively. Statistical analysis showed no significant differences between the two groups in terms of gender, tumor side, age, R.E.N.A.L. score, maximum tumor diameter, preoperative serum creatinine (SCr), and preoperative GFR of the affected kidney (P>0.05). However, preoperative hemoglobin (Hb) levels were significantly higher in the sutureless group compared to the suture group (t=−2.006, P<0.05) (Table 1). The baseline characteristics were generally comparable between the two groups, except for preoperative Hb level.

Table 1. Comparison of baseline characteristics between the suture and the sutureless group.

Parameters	Total	Hemostatic strategies		χ2/t/z	P
		Suture	Sutureless
Gender
Male	23 (34.85)	15 (35.71)	8 (33.33)	0.038†	0.85
Female	43 (65.15)	27 (64.29)	16 (66.67)
Tumor side
Left	35 (53.03)	20 (47.62)	15 (62.50)	1.358†	0.24
Right	31 (46.97)	22 (52.38)	9 (37.50)
Age (years)		50.17±9.82	49.42±8.95	0.308‡	0.76
R.E.N.A.L. score		5.00 (5.00, 6.00)	5.00 (5.00, 5.00)	−1.077§	0.28
Maximum tumor diameter (cm)		3.25 (3.00, 3.63)	2.50 (2.00, 4.00)	−1.899§	0.058
Preoperative Hb (g/L)		129.50±12.51	136.38±14.84	−2.006‡	0.049*
Preoperative SCr (μmol/L)		69.54±17.59	65.92±12.75	0.884‡	0.38
Preoperative GFR (mL/min)		50.24±8.53	51.15±6.22	−0.497‡	0.62

Data are presented as n (%), mean ± SD or median (interquartile range). ^†, the Chi-squared test (χ²); ^‡, the independent samples t-test; ^§, the Mann-Whitney U test; *, statistically significant (P<0.05). GFR, glomerular filtration rate; Hb, hemoglobin; SCr, serum creatinine; SD, standard deviation.

Given the retrospective, single-center design, relatively small sample size, and baseline difference in preoperative Hb, multivariable adjustment was performed using GLMs to account for potential confounders that may influence treatment selection and postoperative outcomes. The adjusted variables included maximum tumor diameter, preoperative Hb, preoperative SCr, and preoperative GFR, with adjustment strategies tailored to each outcome. This multivariable adjustment minimized confounding and may enhance the reliability of the results.

Comparison of preoperative and postoperative laboratory parameters

Preoperative and postoperative laboratory parameters were compared within each group (Table 2). In both groups, postoperative Hb and postoperative GFR were significantly lower than preoperative values (P<0.05). In the suture group, postoperative SCr was significantly higher than preoperative levels (P<0.05). In the sutureless group, however, no significant change in SCr was observed between preoperative and postoperative measurements (P>0.05).

Table 2. Comparison of preoperative and postoperative laboratory parameters by group.

Parameters	Suture		t/z	P	Sutureless		t/z	P
	Preoperative	Postoperative			Preoperative	Postoperative
Hb (g/L)	127.50 (120.75, 137.25)	112.00 (101.75, 119.25)	−5.580†	<0.001*	136.38±14.84	119.54±14.79	8.054‡	<0.001*
SCr (μmol/L)	69.54±17.59	79.26±22.74	−5.337‡	<0.001*	61.90 (56.05, 77.80)	63.35 (55.23, 76.69)	−0.100†	0.92
GFR (mL/min)	50.24±8.53	45.01±8.36	11.895‡	<0.001*	51.15±6.22	48.03±6.24	6.821‡	<0.001*

Data are presented as mean ± SD or median (interquartile range). ^†, the Wilcoxon signed-rank test; ^‡, the paired t-test; *, statistically significant (P<0.05). GFR, glomerular filtration rate; Hb, hemoglobin; SCr, serum creatinine; SD, standard deviation.

Postoperative outcomes and renal function preservation

Unadjusted comparisons of postoperative outcomes between the two groups are shown in Table 3. Compared with the suture group, the sutureless group exhibited a shorter operative time (median 95.00 vs. 120.00 min, z=−2.137, P=0.03). The sutureless group also presented higher postoperative Hb levels (119.54±14.79 vs. 111.17±11.34 g/L, t=−2.579, P=0.01) and lower postoperative SCr levels (median 63.35 vs. 75.95 µmol/L, z=−2.079, P=0.04). In addition, the sutureless group showed a smaller reduction in ΔGFR (3.12±2.24 vs. 5.23±2.85 mL/min, t=3.123, P=0.003) and a more favorable change in ΔSCr (median 1.45 vs. −11.05 µmol/L, z=−2.759, P=0.006). No significant intergroup differences were found in blood loss, drainage volume, tube duration, bed rest period, hospital stay, postoperative GFR, or ΔHb (P>0.05).

Table 3. Unadjusted comparison of postoperative outcomes between the suture and the sutureless group.

Parameters	Hemostatic strategies		t/z	P
	Suture	Sutureless
Operative times (min)	120.00 (90.00, 126.25)	95.00 (77.25, 123.75)	−2.137§	0.03*
Blood loss (mL)	80.00 (60.00, 100.00)	110.00 (60.00, 175.00)	−1.727§	0.08
Drainage volume (mL)	144.40±85.35	136.67±103.74	0.327‡	0.74
Tube duration (d)	4.00 (3.00, 5.00)	4.00 (2.00, 5.00)	−0.566§	0.57
Bed rest period (d)	6.00 (4.75, 7.00)	6.00 (4.00, 7.00)	−0.231§	0.82
Hospital stay (d)	9.00 (8.00, 10.00)	8.00 (8.00, 9.00)	−1.943§	0.052
Postoperative Hb (g/L)	111.17±11.34	119.54±14.79	−2.579‡	0.01*
Postoperative SCr (μmol/L)	75.95 (59.13, 97.00)	63.35 (55.23, 76.69)	−2.079§	0.04*
Postoperative GFR (mL/min)	45.01±8.36	48.03±6.24	−1.668‡	0.10
ΔHb (g/L)	16.00 (9.75, 24.50)	18.00 (9.50, 21.75)	−0.227§	0.82
ΔSCr (μmol/L)	−11.05 (−17.45, 0.68)	1.45 (−6.15, 5.76)	−2.759§	0.006*
ΔGFR (mL/min)	5.23±2.85	3.12±2.24	3.123‡	0.003*

Data are presented as mean ± SD or median (interquartile range). ^‡, the independent samples t-test; ^§, the Mann-Whitney U test; *, statistically significant (P<0.05). ΔHb = Preoperative Hb − Postoperative Hb; ΔSCr = Preoperative SCr − Postoperative SCr; ΔGFR = Preoperative GFR − Postoperative GFR. d, day; GFR, glomerular filtration rate; Hb, hemoglobin; SCr, serum creatinine; SD, standard deviation.

After adjustment for confounders using GLMs, the overall pattern of results was comparable (Table 4). Covariate adjustments were applied as follows: operative time was adjusted for maximum tumor diameter; blood loss, drainage volume, tube duration, bed rest period, hospital stay, postoperative Hb, and ΔHb were adjusted for maximum tumor diameter and preoperative Hb; postoperative SCr and ΔSCr were adjusted for maximum tumor diameter and preoperative SCr; postoperative GFR and ΔGFR were adjusted for maximum tumor diameter and preoperative GFR. The sutureless group was associated with a shorter operative time [adjusted mean 100.82 vs. 116.26 min, mean difference −15.44 min, 95% confidence interval (CI): −30.36 to −0.53, P=0.04]. However, the sutureless group was associated with increased intraoperative blood loss (154.28 vs. 89.59 mL, mean difference 64.69 mL, 95% CI: 21.49–107.89, P=0.003). Moreover, the sutureless group showed lower postoperative SCr (69.10 vs. 75.81 µmol/L, mean difference −6.71 µmol/L, 95% CI: −13.12 to −0.29, P=0.04) and higher preserved postoperative GFR (47.61 vs. 45.25 mL/min, mean difference 2.36 mL/min, 95% CI: 1.05–3.66, P<0.001). The reduction in ΔGFR appeared less pronounced in the sutureless group (2.97 vs. 5.32 mL/min, mean difference −2.35 mL/min, 95% CI: −3.66 to −1.05, P<0.001). No significant between-group differences were observed in drainage volume, tube duration, bed rest period, hospital stay, postoperative Hb, ΔHb, or ΔSCr after adjustment (P>0.05).

Table 4. Adjusted comparison of postoperative outcomes between the suture and sutureless group.

Parameters	Hemostatic strategies, adjusted mean (95% CI)		Mean difference	95% CI for mean difference	P
	Suture	Sutureless
Operative times (min)	116.26 (107.08–126.24)	100.82 (90.31–112.54)	15.44†	0.53 to 30.36	0.04*
Blood loss (mL)	89.59 (74.39–107.90)	154.28 (120.05–198.28)	−64.69†	−107.89 to −21.49	0.003*
Drainage volume (mL)	146.27 (118.43–174.12)	133.40 (95.96–170.84)	12.87‡	−35.04 to 60.79	0.60
Tube duration (d)	3.98 (3.56–4.45)	3.69 (3.18–4.28)	0.29†	−0.43 to 1.01	0.42
Bed rest period (d)	5.62 (5.16–6.12)	5.48 (4.89–6.15)	0.14†	−0.67 to 0.95	0.74
Hospital stay (d)	9.18 (8.66–9.73)	8.42 (7.79–9.10)	0.76†	−0.11 to 1.63	0.09
Postoperative Hb (g/L)	112.80 (109.87–115.73)	116.68 (112.75–120.62)	−3.88‡	−8.92 to 1.16	0.13
Postoperative SCr (μmol/L)	75.81 (71.89–79.93)	69.10 (64.39–74.16)	6.71†	0.29 to 13.12	0.04*
Postoperative GFR (mL/min)	45.25 (44.48–46.02)	47.61 (46.57–48.64)	−2.36‡	−3.66 to −1.05	<0.001*
ΔHb (g/L)	18.70 (16.13–21.69)	17.05 (13.89–20.93)	1.65†	−2.90 to 6.21	0.48
ΔSCr (μmol/L)	5.11 (3.26–8.01)	6.10 (4.10–9.06)	−0.99†	−4.41 to 2.44	0.57
ΔGFR (mL/min)	5.32 (4.55–6.10)	2.97 (1.94–4.00)	2.35‡	1.05 to 3.66	<0.001*

All parameters were adjusted using GLMs. ^†, Gamma distribution with log-link function for non-normal data; ^‡, normal distribution with identity-link function for normal data. *, statistically significant (P<0.05). Mean difference: Suture group − Sutureless group; ΔHb = Preoperative Hb − Postoperative Hb; ΔSCr = Preoperative SCr − Postoperative SCr; ΔGFR = Preoperative GFR − Postoperative GFR. CI, confidence interval; d, day; GFR, glomerular filtration rate; GLMs, generalized linear models; Hb, hemoglobin; SCr, serum creatinine.

Additionally, intraoperative estimated blood loss exceeding 400 mL occurred in 2 cases in the suture group and 1 case in the sutureless group, all of whom received blood transfusions. Postoperative pathology revealed the following diagnoses in the suture group: angiomyolipoma (n=27), clear cell renal cell carcinoma (n=13), papillary renal cell carcinoma (n=1), and oncocytoma (n=1). In the sutureless group, the numbers of these diagnoses were 13, 8, 1, and 2, respectively (Table 5). Benign pathology accounted for 65 % (43/66) of lesions. All surgical margins were reported as negative. In the suture group, one patient developed a Clavien-Dindo grade II surgical incision infection, which resolved after local debridement and wound care. In the sutureless group, one patient experienced a Clavien-Dindo grade I transient fever. No additional complications, such as urinary leakage or delayed bleeding, were observed in either group. During the relatively short-term follow-up period, no signs of tumor recurrence were observed. The bipolar electrocautery hemostatic technique in sutureless LPN for selected exophytic SRMs may be as safe and feasible as the suture technique.

Table 5. Comparison of postoperative pathological results.

Parameters	Total	Hemostatic strategies		χ2†	P
		Suture	Sutureless
Angiomyolipoma	40 (60.61)	27 (64.29)	13 (54.17)	–	0.68
Clear cell renal cell carcinoma	21 (31.82)	13 (30.95)	8 (33.33)	–
Papillary renal cell carcinoma	2 (3.03)	1 (2.38)	1 (4.17)	–
Oncocytoma	3 (4.54)	1 (2.38)	2 (8.33)	–

Data are presented as n (%). ^†, Fisher’s exact test.

Discussion

In conventional LPN, renal artery clamping is routinely used to control intraoperative hemorrhage, thereby maintaining a clear surgical field and ensuring safe tumor excision and renal parenchymal reconstruction (14,15). Nevertheless, renal artery clamping inevitably prolongs WIT, which may trigger IRI (16). WIT has long been recognized as an important modifiable factor associated with postoperative renal function (17). Notably, renal damage increases with ischemia time, indicating that there is no absolutely safe duration of WIT (18). Given the important role of minimizing WIT in mitigating ischemic renal injury, researchers have developed multiple strategies to reduce or abolish WIT, including preoperative superselective transarterial embolization (19), selective renal artery clamping (20), early unclamping (21), and the off-clamp technique (22). Among these approaches, the off-clamp technique represents the theoretically optimal zero-ischemia strategy by completely eliminating WIT and subsequent IRI. Two recent meta-analyses suggest that the off-clamp technique may help preserve renal function and lower complication risks, despite potential increases in intraoperative blood loss (23,24). For exophytic SRMs, renal parenchymal defects are relatively limited, and intraoperative hemorrhage is generally controllable, rendering tumor resection feasible without renal artery clamping. In our study, renal arteries were routinely exposed intraoperatively in all patients, yet all operations were completed under an off-clamp setting. Collectively, the off-clamp technique appears safe and feasible in appropriately selected patients.

Beyond WIT, renal parenchymal preservation and renal reconstruction methods are also critical to postoperative renal function protection (25). Recent studies suggest that preservation of renal parenchymal volume may be the primary determinant of postoperative renal function, with WIT representing a secondary factor (26,27). Furthermore, the quantity and quality of preserved healthy renal parenchyma are key predictors of renal function recovery (28). Traditionally, surgical margins in renal oncological surgery range from 0.5 to 1.0 cm (29). However, accumulating evidence indicates that a 0.5 cm margin is sufficient for complete tumor excision without elevating local recurrence rates (30). Tumor enucleation represents a favorable strategy as it largely spares healthy renal parenchyma (31). Moreover, simple tumor enucleation achieves oncological outcomes comparable to those of standard LPN (32). In this study, we adopted a relatively conservative surgical strategy, setting the resection margin at 0.3–0.5 cm. Preliminary findings from the short-term follow-up showed no local recurrence. While a positive margin does not necessarily imply residual tumor within the renal parenchyma, achieving negative margins is a more idealized scenario, closely associated with favorable oncological outcomes after LPN (33).

Historically, renal injury secondary to suture-based reconstruction was considered unavoidable. Conventional renal parenchymal suturing techniques may inadvertently damage small intrarenal vessels, leading to ischemic injury of preserved nephrons and subsequent impairment of postoperative renal function (1). Recent studies have demonstrated that suturing may induce renal parenchymal necrosis up to 5–10 mm in depth and increase the risk of renovascular complications, including pseudoaneurysms and arteriovenous fistulas (14,34). In conventional LPN, double-layer (inner and outer) suturing is routinely performed to repair post-resection parenchymal defects and achieve hemostasis (35). Nevertheless, a randomized controlled trial by Yong et al. indicated that single-layer suturing yields better preservation of renal parenchymal volume and function relative to double-layer suturing (36). Accordingly, minimizing sutures where technically feasible represents an important strategy for renal function protection.

Sutureless techniques in LPN may offer potential benefits for renal function preservation by reducing suture-related vascular injury, which could represent an important technical advancement for postoperative renal recovery (1). Moreover, conventional suturing techniques are generally associated with a steep learning curve, whereas sutureless approaches appear technically simpler with fewer procedural steps, which may facilitate clinical adoption (14). Sutureless LPN may serve as a potential alternative to conventional sutured repair and is possibly associated with more favorable perioperative outcomes and a higher likelihood of achieving the trifecta (37). In recent years, multiple intraoperative energy modalities, including radiofrequency, microwave, argon beam coagulator, monopolar/bipolar electrocautery, and laser, have been explored for sutureless hemostasis of the resection bed during LPN (14,29,34). Among these, bipolar electrocautery represents one of the most commonly used electrosurgical tools. Bipolar electrocautery delivers energy at 70–80 °C to induce protein coagulation, which may achieve effective hemostasis while potentially lowering the risk of collateral tissue carbonization (33). It also appears cost-effective, with no additional demand for supplementary materials or equipment. In an observational non-comparative study, off-clamp sutureless LPN assisted by bipolar coagulation appeared feasible for renal tumors with low nephrometry score, albeit without a control group (38). In line with such preliminary evidence, our retrospective case-control study of selected SRMs employed bipolar coagulation for resection-bed hemostasis under off-clamp conditions, with acceptable hemostatic outcomes achieved. Moreover, following adjustment for potential confounders via GLMs, the sutureless group was associated with shorter operative time and exhibited a trend toward less pronounced early-postoperative renal function decline relative to the suture group.

Although off-clamp sutureless techniques offer potential benefits, maintaining a clear operative field and controlling significant bleeding remains challenging, requiring conversion to renal artery clamping and suturing in cases of major hemorrhage (39). Recent evidence suggests that under favorable anatomical conditions, renorrhaphy can be safely omitted. Perioperative safety outcomes including blood loss and complications are comparable, whereas long-term renal functional preservation demonstrates no statistically significant advantage relative to conventional sutured repair (40). However, our single-center retrospective experience differed slightly. In our study of selected exophytic SRMs, the sutureless group was associated with increased intraoperative blood loss compared with the suture group, which may be attributed to the lack of suture compression of the resection bed and more extensive bipolar coagulation under off-clamp conditions, while short-term renal function appeared to be preserved. Notably, the incidence of severe bleeding requiring transfusion was low and comparable between groups. Given the above considerations regarding bleeding control and perioperative safety, off-clamp sutureless approaches require strict patient selection, particularly for exophytic SRMs (41). A primary concern with sutureless renal repair is postoperative complications, notably bleeding and urinary leakage. However, relevant meta-analyses have shown no significant difference in overall postoperative complication rates between sutureless and conventional sutured techniques (42). One retrospective study reported no postoperative renal artery pseudoaneurysms following off-clamp sutureless LPN (43), while another retrospective cohort demonstrated no technique-related complications including bleeding and urinary leakage (44). In our short-term follow-up, no urinary leakage or delayed hemorrhage was noted. Collectively, these findings support the feasibility of sutureless renal reconstruction and suggest that renorrhaphy may be omitted in LPN for selected exophytic SRMs.

Several limitations should be acknowledged in this study. Non-random allocation, temporal effects, and surgeon preference may influence outcomes. Firstly, the relatively small sample size and single-center design may have impacted the statistical power and generalizability of our findings. Secondly, the retrospective nature of the study, as opposed to a prospective design, inevitably introduces some degree of selection bias. The retrospective, non-randomized design and the fact that the sutureless technique was introduced later in the institutional experience represent important sources of the temporal and learning-curve bias. Consequently, causality cannot be directly inferred from the observed associations. Thirdly, all procedures were performed by the same surgical team. While this improves internal consistency, it also limits external generalizability and raises the possibility that outcomes are influenced by team-specific experience and learning-curve effects. For example, operative time decreased over the study period, reflecting both the adoption of the sutureless technique and the accumulation of expertise. Given that this technique was being performed at our institution for the first time, a conservative case selection strategy was employed to maximize patient safety and therapeutic benefits. Consequently, a considerable proportion of patients with exophytic SRMs of low oncological risk, such as angiomyolipoma, were included. Additionally, although not statistically significant, the median maximum tumor diameter in the sutureless group was smaller than that in the suture group. This baseline characteristic might have favored better preservation of nephrons and renal function postoperatively. These factors may partially explain the satisfactory postoperative functional and surgical outcomes observed. Our cohort consisted exclusively of exophytic, peripheral lesions ≤5 cm in size, with a median R.E.N.A.L. score of 5, and 65% of the pathologic diagnoses were benign. Therefore, extrapolation to larger, endophytic, or high-risk renal tumors is limited. Our data were confined to the early postoperative period. Consequently, the present findings reflect only short-term outcomes. Longer follow-up is required to establish the long-term renal protection and surgical results. Future research should prioritize large-scale, multi-center, prospective, randomized controlled trials. Such designs would significantly enhance the reliability of the results and broaden their applicability across diverse clinical settings, thus enabling a more comprehensive evaluation of the utility of sutureless techniques.

Conclusions

In conclusion, bipolar electrocautery hemostasis during sutureless LPN performed under zero-ischemia may be feasible for selected exophytic SRMs. In these lesions, the technique is associated with a shorter operative time, a smaller early postoperative decline in renal function, and no increase in short-term complications. However, the study has several limitations, including its retrospective design, small sample size, single-center experience, potential temporal bias, and short follow-up. Consequently, the findings should be regarded as hypothesis-generating, and large-scale, multi-center, prospective randomized controlled trials are urgently needed to validate the long-term safety and efficacy of this approach before it can be widely adopted.

Supplementary

The article’s supplementary files as

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. This study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the Ethics Committee of the First Affiliated Hospital of Army Medical University [(B)KY2024153]. The Ethics Committee waived the patients’ informed consent due to the retrospective nature of the study.

Data Sharing Statement

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DOI: 10.21037/tau-2026-0250