The Use of Self-Retaining Barbed Suture Preserves Superior Renal Function During Laparoscopic Partial Nephrectomy: A PADUA Score Matched Comparison

Introduction

Renal masses are common neoplasms in the urinary tract. Recent advances and the wide use of imaging technology have enabled the discovery of more small renal masses. ¹ Thus, as a minimally invasive option for the management of small renal masses, demand for laparoscopic partial nephrectomy (LPN) has greatly increased. Compared with radical nephrectomy, partial nephrectomy (PN) has shown equivalent oncological outcomes and an effective preservation of renal function. ²

There are many predictive variables of renal function loss after LPN. Among these factors, warm ischemia time (WIT) is the only one that can be modified. ³ The impact of warm ischemia on renal function has been extensively studied, but a consensus on its effectiveness and use has still not been reached. Recent studies consider 25 minutes as the acceptable safety threshold of WIT during LPN and suggest that every minute has a deleterious effect on renal function outcomes when the renal hilum is clamped.^4,5 Therefore, technological innovations that can shorten the WIT are of great value.

Classically, interrupted suturing was used for parenchymal closure. Gradually, most surgeons have used knotless renorrhaphy ⁶ or a sliding clip renorrhaphy technique ⁷ to maintain continuous tension and to avoid slippage. Recently, a new absorbable, self-retaining barbed suture (SRBS) was considered effective and was first applied in plastic surgery and gynecology. In urology, SRBS has been applied in robot-assisted laparoscopic prostatectomy and LPN.^8,9 Given its knotless properties and capacity to automatically maintain tension, it is believed to shorten the WIT.

In the past few years, we have used two different single-layer suture techniques for renorrhaphy: SRBS and the sliding clip technique. In this study, we conducted a retrospective analysis of perioperative outcomes to evaluate the efficacy and effectiveness of these techniques.

Materials and Methods

Results

All 82 patients (41 matched cases in each group) successfully underwent LPN without conversion to open surgery or nephrectomy. Among 82 patients, 7 (8.6%) had an additional port (3 in the sliding group and 4 in the SRBS group). Clinical characteristics and perioperative outcomes of patients are presented in Table 1. No significant differences between groups were found for age, gender distribution, body mass index, tumor size, American Society of Anesthesiologists score, PADUA score, and mean operative time (all P>.05). There were significant differences between groups regarding the mean WIT (G1 versus G2, 27.5 minutes versus 20.7 minutes; P<.05) (Table 2). The mean estimated blood loss was similar in the SRBS and sliding clip groups (G1 versus G2, 188 mL versus 180 mL; P>.05) (Table 2).

With regard to perioperative complications (Table 2), 3 patients presented relatively severe bleeding during the operation (2 in G1 and 1 in Group 2), and all 3 cases received intraoperative transfusion (all cases were Clavien Type II). Two patients presented with hematuria (1 in G1 and 1 in G2), and both cases of hematuria recovered after intravenous infusion of hemostatic drugs (both cases were Clavien Type II). Two patients had postoperative hemorrhage (1 in G1 and 1 in G2), of which 1 case (in G1) received transfusions (Clavien Type II) and 1 received transfusions and percutaneous selective embolization (Clavien Type IIIa). In addition, urinary fistula was observed in 1 case (in G2), in which jejunojejunostomy placement was performed (Clavien Type IIIb). In comparing complications by suture techniques, no significant difference was found between groups.

As shown in Table 1, there were no differences between the groups in preoperative GFR levels of the affected kidney, whereas a significantly lower GFR reduction of the affected kidney was found in the SRBS group (G1 versus G2, 29% versus 20.8%; P<.05) (Table 2).

Discussion

There has been much progress in LPN since its first application for small renal masses. LPN has been more widely used but remains technically challenging. Gill et al. ² retrospectively analyzed 1800 patients who underwent open PN or LPN and reported a 10-minute longer WIT in the LPN group, highlighting the difficulty of the procedure, despite its advantages of less invasion and rapid recovery. Even for an experienced laparoscopic surgeon, it can be time consuming and complicated to complete the closure of the defect with one hand while maintaining the tension of the suture with the other hand during LPN. In an attempt to simplify the procedures, continued innovations in suture designs have been undertaken. Canales et al. ¹² have described a relatively simple technique by substituting Hem-o-lok clips for knot-tying, which significantly reduces the complexity of suturing. On this basis, Benway et al. ⁷ introduced sliding clip renorrhaphy, which is distinguished by sliding the clip toward the kidney. Shikanov et al., ¹³ for the first time, applied SRBS for renorrhaphy during LPN in the porcine model and reported SRBS as effective and efficient but that it did not result in benefits with regard to shorter WIT.

Like many other surgeons, we also focused on modifying suture techniques in the past few years. Here, we compared SRBS and the sliding clip technique. Similar comparisons in previous studies^14,15 typically compared SRBS with the conventional running suture or knotless technique. Previous studies have reported that the use of SRBS can shorten WIT 10.1%–32.1%.^14,15 In our study, SRBS usage was associated with significantly decreased WIT compared with the sliding clip group. Without the need for tension management by the nondominant hand, SRBS usage frees up both hands, thus greatly enhancing ease and speed during renorrhaphy. In addition, obviating the need for both knot-tying and clips also contributes to WIT reduction. Moreover, we believe SRBS can shorten the learning curve of intracorporeal suturing for less experienced surgeons.

Unlike previous studies, we found a different result in that the complication rate and blood loss in the SRBS group were similar to those in the sliding clip group. Moreover, the complication rate for the sliding clip group in our study was already lower than that of the non-SRBS group in previous studies. Our experience suggested that both SRBS and the sliding clip technique might provide an effective renal parenchyma repair.

Serum creatinine level is inappropriate for estimating renal function changes in the affected kidney because the normal contralateral kidney compensates for function. ¹⁶ Thus, we used ^99mTc-DTPA to evaluate renal function. One of the noteworthy findings of our study is that GFR reduction was significantly lower for the SRBS group. As expected, the shorter WIT is accompanied by less injury to the affected kidney^4,5; thus patients in the SRBS group had a better early renal function recovery.

It should be noted that there are fundamental differences in renorrhaphy techniques between the present and previous studies. Olweny et al. ¹⁵ and Zondervan et al. ¹⁴ only used SRBS for closure of the deep tumor bed or the superficial layer, whereas another layer was repaired with conventional polyglactin suture. In our study, we used simplified techniques in that a single-layer SRBS was used for closure of the entire tumor bed. We believed a decrease in WIT could be attained without sacrificing efficiency in compressing the parenchyma by simultaneously providing enough tension. Hayn et al. ¹⁷ also introduced a simplified single-layer technique with a figure-of-eight suture and proved its safety and effectiveness. Moreover, we did not find significant differences in the proportion of cases with significant hemorrhage between the present and previous studies (8.1% versus 3.0%–8.0%), indirectly confirming the safety of this technique. In addition, they used the transperitoneal approach in almost all the cases, whereas all patients in our study underwent LPN through a retroperitoneal approach, suggesting that retroperitoneal LPN can also benefit from SRBS.

In our series, even for large defects, a single-layer closure was also applicable. There are some technical tips with regard to our single-layer suture. First, if indicated, the collecting system and large blood vessels should be repaired prior to closure of the renal defect. Second, we used a 1-0 needle with a 5/8 radian, which facilitates passage of the needle through the capsule and beneath the entire resection defect. When proceeding with the first and final tissue bite, we passed the needle though the renal parenchyma just beyond the wound edge, through which the parenchyma was more effectively compressed and slippage was well prevented. Third, sutures were placed through the renal capsule 1 cm from the wound edge. It is crucial that the bottom of the tumor bed is also compressed. To minimize the risk of tearing, the suture should be tightened through pulling it perpendicular to the capsule.

Some limitations of this study need to be addressed. First, as a retrospective study, some potential confounders existed. However, the PADUA scores of patients between groups were matched, and we excluded cases earlier in the surgeon's career to mitigate the impact of the learning curve; thus bias was minimized. Second, the sample size is relatively small. A larger sample size would have conferred higher value to the comparison. Third, although the results show that SRBS resulted in better early renal function recovery of the operated kidney, studies based on long-term outcomes are still required to fully establish oncological efficacy. Fourth, we conclude that single-layer SRBS is as safe and efficient as two-layer SRBS based on our experience and review of the literature, and further randomized and controlled trials to confirm our conclusions are warranted.

Conclusions

Our experience shows that the single-layer SRBS offers an effective and safe renal parenchyma repair. In addition, SRBS appears to significantly shorten WI and, most critically, results in better early affected renal function recovery.