On a standard basis, nephron-sparing surgery has been used in patients with a renal cell carcinoma having a solitary kidney, bilateral synchronous tumors or a systemic disease that could potentially jeopardize renal function [7
]. However, due to the recently published promising cancer-free survival rates of patients undergoing nephron-sparing surgery for tumors less than 4 cm, this approach gains widespread acceptance in patients with a normally functioning contralateral kidney [8
]. Furthermore, Leibovich et al. [11
] demonstrated that even patients with renal cell carcinoma from 4 to 7 cm treated with nephron-sparing surgery had an excellent cancer-specific and metastases-free survival when the tumors had an exophytic growth pattern and presented with minimal risk of invasion of the collecting system. These promising oncological results, combined with advances in renal imaging and improved surgical techniques, led to an increase of nephron-sparing procedures.
The critical steps during nephron-sparing surgery are the resection of the tumor with an adequate margin of benign tissue around the tumor, as well as a sufficient haemostasis and closure of the collecting system. The surgical technique applied depends on the size and location of the renal tumor.
In little peripheral renal masses, haemostasis may be achieved after tumor resection using coagulation and a haemostyptic agent without any sutures. Finley et al. [12
] reported on a series of 15 patients who underwent a sutureless haemostasis after excision of small renal masses (range 1.1 to 3.5 cm) using a fibrin glue – oxidized cellulose sandwich. Otherwise, the mainstay of haemostasis has to be accomplished by compressing the tissue around the renal defect. Usually, for this purpose the renal capsule is sutured with horizontal mattress sutures over the length of the defect [13
]. There is a theoretical possibility of loss of functional kidney tissue due to scarring caused by the suture line passing through the renal capsule and parenchyma, even though to date no experimental data exist supporting this hypothesis. The maximum tensile force that may be applied onto the sutures is limited by the tensile strength of the renal capsule and parenchyma. The tearing of the suture through the capsule is of major concern. Therefore, alternative methods to buttress the closure of the renal parenchyma using exogenous material like Gore-Tex [13
] or Teflon [14
] have been investigated. The exogenous materials prevent the tearing of the sutures through the renal parenchyma, leading to a tighter, more haemostatic and watertight closure of the defect [13
In the case of larger defects, the renal parenchyma has to be folded to close the defect with sutures. Therefore, the closure is hard to achieve and associated with a greater risk of complications [2
]. In these cases, the use of exogenous materials like perirenal fat or oxidized cellulose was propagated to cover the defect [15
]. Wainstein et al. [17
] successfully used a polyglycolic acid mesh in three patients to obtain a secure closure of a renal defect [17
]. In a recent study, O'Connor et al. [18
] described the use of SIS to cover the defect in 24 partial nephrectomies. In their study, haemostasis was achieved by excising the defect with a harmonic scalpel, using coagulation of the parenchyma with an argon beam, ligation of visible vessels and closing the collecting system with interrupted, chromic sutures. The SIS was placed over the defect with several figure-of-eight chromic sutures.
Compared to the study by O'Connor et al. [18
], we optimized the haemostyptic procedure. To minimize the loss of functional kidney tissue, we used neither a harmonic scalpel to excise the tumor nor the argon beamer to coagulate the parenchyma. The adverse effect of coagulation on the remaining renal parenchyma was demonstrated in the study by Murphy et al. [19
]. Microscopic changes of the renal parenchyma caused by the applied heat were noted as deep as 1 cm below the surface area. To achieve haemostasis, we ligated visible vessels and applied a haemostyptic agent. Furthermore, we only slightly approximated the edges of the kidney without applying tension on the renal capsule. Finally, we fixed the hydrated SIS more tightly over the renal defect with a running suture mimicking the fixation of a drumhead. This led to a uniform tension on the renal defect (Fig. ).
The intraoperative blood loss (median 730 cc) and transfusion rate (29.1%) in the present study is comparable to the literature [20
]. Furthermore, the reported incidence of postoperative bleeding complications and urinary fistulas following nephron-sparing surgery is 0 – 7.9% and 1 – 10.1%, respectively (see Table ) [3
]. However, when comparing the data in the literature, it is mandatory to consider the diameter of the renal lesions. Due to the broadening of the indication for elective nephron-sparing surgery in recent years, only few studies exist reporting complication rates in series with larger tumors such as we present in our study. Both the postoperative bleeding and urinary leakage rates were 1.8%. These results are superior to recent studies with comparable tumor size, reporting bleeding rates of 2.9% and urinary leakage rates of 5.8% and 10.1% [20
Reported major peri- and postoperative surgical complications after nephron-sparing surgery for solid renal lesions