With the advance in technology and increased use of abdominal imaging, the incidence of small renal masses has significantly increased in the past decade [1,2].

The management of small renal masses varies and includes: surgical excision either by partial or radical nephrectomy, focal ablative therapies or mainly in elder or comorbid patients active surveillance [3]. According to recent American Urological Association guidelines for treating small renal masses (cT1), the oncological outcome in terms of disease specific survival following partial nephrectomy (PN) equals that of a radical approach. However, nephron sparing surgery (NSS) presents with improved overall survival attributed to improved kidney function and decreased metabolic or cardiovascular complications [4,5]. Robotic partial nephrectomy (RPN) is a relatively safe NSS approach. However, a major perioperative complication is extensive bleeding and blood loss necessitating blood transfusion [6]. This complication became less common since the era of laparoscopic surgery [7], possibly due to the effect of pneumoperitoneum and increased intra-abdominal pressure on renal vessels. However, RPN can still cause decreased hematocrit and increased need for packed red blood cell (RBC) transfusion which might poorly affect oncological outcomes as seen in colorectal cancer [8]. After removing the renal mass, renorrhaphy (tumor bed closure) is performed with absorbable sutures aimed to stop dissected parenchymal blood vessels from bleeding. In the current study we introduce a novel hemostat adhesive to control renal bleeding during RPN. The aim of the study was to perform an in vivo evaluation of safety and efficacy of this novel hemostat in RPN.

The current study was a prospective single center single arm trial involving 20 patients who underwent RPN using Starsil® hemostat for small renal masses. Patients were operated between the years 2017-2018. After receiving approval from the local Institutional Review Board (IRB: 0241-16 RMB), all patients gave full consent to participate in this study.

2.3 Surgical technique

All procedures were performed by a single surgeon. Patients were placed in a flank position with the robot docked over the ipsilateral side. A standard three arm DaVinci Si surgical system (Intuitive Surgical, Sunnyvale, CA, USA) via transperitoneal approach was used for all cases. Pneumoperitoneum at 15 mmHg was achieved using the "Hasson" technique [10]. A 30 degree down camera lens was used throughout the operation. After colon reflection, the kidney was mobilized and the hilum was identified for the placement of a laparoscopic bulldog on the renal artery. All tumors were resected with monopolar scissors. The resection site base was not routinely cauterized. One Starsil® Hemostat application bottle consisting of 5 grams of powder was used for each procedure. The powder was applied with a feeding tube through a laparoscopic assistant port (Figs. 1 and 2). Renorrhaphy was then performed using 3-0 vicryl sutures with Lapra-TY® clips for deep cortical and blood vessels closure. We used 1-0 vicryl sutures with 10 mm Hem-o-lock® and Lapra-TY® for external cortical closure. The robotic needle driver was used to slide the Hem-o-lock® and Lapra-TY II® clips on the opposite end down the suture to a desired tension. Thereafter, the clamps were removed and the kidney was inspected for hemostasis. Hemostasis was rated as adequate if no excessive bleeding or oozing was observed.

Figure 1.

Starsil® Hemostat kit before insertion during robotic partial nephrectomy.

Figure 2.

A) Starsil UniTip - spray applicators that allow accurate delivery of the Starsil® Hemostat during robotic partial nephrectomy. B) Administration of Starsil® Hemostat during robotic partial nephrectomy: Robotic arm directing the feeding tube into the tumor bed before the assistant is applying the hemostat.

Twenty RPN procedures were performed using Starsil® Hemostat for bleeding control assistance. Patient and renal tumor characteristics were collected (Table 1). Average blood loss was 346 mL (50-1400 mL). Mean surgeon satisfaction with bleeding control was 8.3 on average when recorded 24 hours post-operation (VAS, Table 2). In 17/20 procedures (85%), bleeding control was adequate (VAS score 9-10). In one case (5%), additional stitches were required after removal of the arterial clamp. Surgeon satisfaction from the hemostat was scored low (VAS < 5) in only three cases (15%).

Two cases of high complexity R.E.N.A.L score tumors were noted. These patients required blood transfusion during or after the operation: One patient (R.E.N.A.L. 9, hilar tumor) lost 1000 mL of blood during the operation and received 2 units of packed RBCs. After the operation, he suffered from a urinary leak that was treated with insertion of a double J ureteral stent. Another patient (R.E.N.A.L. 10) was converted to a robotic radical nephrectomy due to proximity of the tumor to the main renal artery. These events were classified as non-product related.

None of the patients developed an allergic reaction to the hemostatic adhesive powder. All patients were discharged in good health (average hospital stay was 4.8 days). No adverse events related to the product were noted in the post-surgical follow up period of up to 6 months. No cases of arteriovenous fistula or pseudoaneurysm were noted. None of the patients needed conversion to open surgery, reoperation or selective angio-embolization for late bleeding. Review of the pathology specimens from the operations, demonstrated 16 cases of clear cell renal cell cancer (RCC) and 4 cases of oncocytoma.

Minimally invasive NSS is the gold standard operative procedure for small renal masses due to complete local resection of the renal tumor while preserving maximal possible functioning parenchyma [11]. Tumor bed closure is performed by approximating the transected margins with various suture techniques, sometimes together with hemostatic substances [12]. Acquiring satisfactory bleeding control during RPN is ultimately achieved by experienced urologic surgeons, and although severe, hemorrhage after partial nephrectomy is a rare event [13], maximizing hemostasis is still needed, especially in case of complex tumors that are either very endophytic, large or in close proximity to the renal hilum.

Hemostasis control and tumor bed closure are considered the most difficult steps during a laparoscopic partial nephrectomy mostly due to the relatively prolonged warm ischemia time. To overcome this challenge, several tissue sealants and adhesives were developed to aid or replace suturing the renal parenchyma [14,15].

Brandão et al., compared the use of sutures versus biological glue for the closure of porcine renal parenchyma during laparoscopic partial nephrectomies. They found that the use of Bioglue® (CryoLife Inc.), a surgical adhesive that contains purified bovine serum albumin (BSA) and glutaraldehyde, had a significantly lower warm ischemia time without compromising bleeding control [16]. Based on these results, Hidas et al., compared the clinical outcomes of open partial nephrectomy (OPN) using Bioglue® versus traditional suturing technique for tumor bed closure. The use of Bioglue® reduced the estimated mean blood loss (P = 0.001) and blood transfusion rates (P = 0.014) [17].

Numerous hemostatic agents are nowadays in clinical use for laparoscopic partial nephrectomy operations [18-20] and a meta-analysis by Galanakis et al., demonstrated that most adhesive agents show good results for complete bleeding control or facilitation of hemostasis [21].

In our current study we have elected to use Starsil® Hemostat, a plant-derived hemostatic powder that is commonly used for treatment of sternal bleeding after median sternotomy [22]. According to Hemotec Medical GmbH, the use of Starsil makes it possible to achieve bleeding control in diverse cardiac operations such as coronary-arterial bypass graft (CABG), implantation of pacemaker or an implantable cardioverter defibrillator (ICD), replacement of ascending aorta for repair of aortic aneurysm, aortic valve replacement and even heart transplantations [23].

According to the product manufacturing information, one of the main advantages of Starsil® Hemostat is that unlike xenograft products such as bovine derived, this is a plant-derived product with diminished chance for an allergic reaction or other adverse effects. Another advantage is that this is an off-the-shelf product and there is no need for storage at low temperatures prior to application. We also found it to be very easy to use in the laparoscopic setting by the robotic assistant.

In the current study, we described for the first time the use of Starsil® Hemostat in genitourinary operations. In our trial, it was found to be safe, easy to use and adjunctive measure for facilitating hemostasis in robotic partial nephrectomy operations. Surgeon satisfaction with hemostasis was high in most cases.

Our study had several limitations: first, in each RPN, we elected to use only one unit of Starsil® Hemostat for bleeding control. The option of using a second unit in case of unsatisfactory bleeding control, was not part of this safety study. Second, the current study was a single arm trial with no control arm. Third, all RPNs were performed by a single surgeon who rated satisfaction of the product. In the future, we hope to perform a multi-center placebo-controlled trial so that the safety and efficacy of Starsil® Hemostat will be fully evaluated.

Tumor bed closure during NSS with the STARSIL® Hemostat adhesive is safe, feasible and easy to use. It has the potential to reduce blood loss and transfusion rate in patients undergoing RPN.

We thank all the co-authors that participated in the study.

There is no conflict of interest, real or perceived.