Renal cell carcinoma (RCC) accounts for 2%–3% of all malignancies (1), with a higher incidence in Western countries. In Europe, the mortality rate of RCC increased in the early 1990s, then stabilized, and is now decreasing (2). RCC comprises a broad spectrum of entities described in the 2016 World Health Organization (WHO) classification. There are three main histotypes of RCC: clear cell (ccRCC), papillary (pRCC: type I and type II), and chromophobe (chRCC) (3). This classification has been confirmed by genetic and cytogenetic analysis (4, 5). Surgical treatment is the choice for localized and small forms of RCC. Both in terms of choice of surgery, partial nephrectomy (PN), and radical nephrectomy (RN) and the surgical technique used (laparoscopic/robotic surgery vs. open surgery), the most appropriate approach is guided by correct clinical staging. Many retrospective studies have been performed on kidney-confined and size-limited T_1b RCC patient populations which have shown an overlapping cancer-specific survival between a conservative approach (PN and RN) (6, 7). In addition, studies have demonstrated improved preservation of renal function in patients undergoing PN, with a decrease in metabolic and cardiologic disorders (8, 9) and a decrease in deaths due to cardiac issues with an increase in overall survival (8–12). Therefore, in addition to oncologic radicality, the primary goal for an ideal PN is maximum preservation of renal function (13). Even in patients with preoperative renal failure, it is advisable to lean toward a more conservative approach to limit the long-term risks of needing hemodialysis treatment. In the international literature, emphasis has been placed on the role played, to the detriment of renal function, by renal ischemia time and renal parenchyma loss during PN surgery. However, on the other hand, no significant differences in terms of days of hospitalization, peri- and postoperative complications, number of blood transfusions, and estimated blood loss (EBL) were noted between PN and RN. Considering these data, it is important to reduce or eliminate the ischemia time and remove healthy renal parenchyma during mass resection or rendered nonfunctional by subsequent hemostatic suturing. Moreover, laparoscopic surgery has gained acceptance in the treatment of urologic oncologic disease with less postoperative pain, less blood loss, and shorter hospital stay than open surgery (14). Complications that can occur following carbon dioxide (CO₂) insufflation during laparoscopic surgery include subcutaneous emphysema (SCE), pneumothorax (PTX), and pneumomediastinum (PMS). Homeostasis can be negatively affected by the increase in intra-abdominal pressure, consequent to the insufflation of CO₂, causing significant changes in the cardiovascular and respiratory systems (15, 16). Conventional CO₂ insufflation systems frequently have an inadequate response, generally due to a delay, to intraoperative pressure loss due to aspiration or smoke evacuation. A valveless insufflation system introduced in 2011, now commercially available as AirSeal® Insufflation System (AIS) (Conmed, Utica, NY, USA), has significant advantages over conventional insufflation systems. The AirSeal® mode is designed to provide CO₂ insufflation that ensures stable pneumoperitoneum and continuous suction of surgical vapors during laparoscopic procedures. This feature is very useful during procedures where numerous monopolar instrumentations are used. The objective of our study was to compare the surgical outcomes of laparoscopic partial nephrectomy (LPN) procedures performed using the standard CO₂ insufflation with those of procedures in which the AirSeal® intelligent insufflation system was used.

The two groups of patients had similar preoperative characteristics. The mean age was 61.3 years (median 60; IQR 19.0) for group A and 65.9 years (median 66; IQR 15.0) for group B, respectively. The mean lesion size, as assessed by contrast-enhanced CT, was 29.6 mm (median 28.5 mm; IQR 20.0) and 32.1 mm (median 27 mm; IQR 23.0), respectively. The observed RENAL nephrometry score (8) was on average 6.2 (median 6.5; IQR 2.0) for group A, while for group B, it was 5.0 (median 5.0; IQR 2.0), indicating a dissimilar complexity of the treated tumors that influenced the choice of the most appropriate surgical approach. Other patient characteristics are summarized in Table 1. The mean operative time was shorter in the first group (group A: mean 109.0 min, median 107.5 min, IQR 85; group B: mean 121.0 min, median 120.0 min, IQR 50.0). Regarding the “hot” ischemia time, it too was found to be shorter in group A with a median of 18 min, compared with a median of 20 min in group B. In addition, more cases performed as “zero ischemia” was observed in group B (11 vs. 8). No positive surgical margins were evident in either group (Table 2). No SCE cases occurred in either group. There was a conversion to open surgery required to complete the procedure in only one patient of group B. A major postoperative complication developed in one patient in group B (class III according to the Clavien–Dindo classification): renal bleeding that required superselective embolization in interventional radiology (Table 3).

In some studies, warm ischemia lasting longer than 25 min has been shown to determine irreversible renal injury after PN (22). However, recent work shows that every minute counts if the renal hilum is clamped during PN (23). As a result, minimally invasive approach is particularly challenging because advanced surgical skills are needed to achieve effective tumor resection, maintain hemostasis, and perform subsequent renorrhaphy, within the shortest time possible. The ability to clearly see the surgical field is also crucial to facilitating surgical maneuvers and reducing overall operative time. By delaying the intraoperative pressure drop, the conventional CO₂ insufflation systems often respond. In fact, conventional insufflators typically switch from CO₂ insufflation for approximately 3 s to a pause of 1 s and then measure the pressure and cyclically reinflate to maintain the set pressure. Therefore, conventional mechanical insufflators cause cyclic oscillation of the pressure inside the abdomen (24); as a consequence, these fluctuations, suction maneuvers, or smoke evacuation usually lead to the collapse of the abdominal cavity, which can only be avoided and compensated by increasing the gas insufflation pressure. Postoperative shoulder pain can occur due to excessive stretching of the diaphragm muscle fibers caused by increased CO₂ pressure (25). Conventional trocars have a cannula with a proximal unidirectional valve and a cannula with a distal hollow thread. Gas escapes from the abdominal cavity when the trocar valves are opened to accommodate the instruments. The resulting moisture and surgical smoke impair the surgeon's vision and often contaminate laparoscopic lenses, requiring suctioning and cleaning of the instruments, which prolongs operative time (26). AirSeal® therefore represents a new insufflation system that uses trocars without valves or membranes, responding immediately to slight variations in intra-abdominal pressure (27). The AirSeal® system reduces the consumption of CO₂ during surgery (28). Thanks to real-time pressure equalization, the AirSeal® system allows the surgeon to easily work at lower pressures, reaching up to 7 mmHg, with inlet gas flow never exceeding 3 L/min, providing further benefits to the patient, who finds relief both during the procedure and during postoperative recovery. To date, few studies have examined the role of the AirSeal® system compared with the standard CO₂ insufflation for the same type of surgery. Herati et al. (27) reported the first prospective comparative study between the AirSeal® system (26 patients) and a standard trocar (25 patients). The authors find that the mean operative time as well as the amount of CO₂ consumed were significantly lower in the group where the AirSeal® system was used. Annino et al. (29) published a comparative study between the AirSeal® system (67 patients) and the standard insufflation system (55 patients) in the field of robotic partial nephrectomy. The mean operative and warm ischemia time was significantly shorter in the first group. Feng et al. (30) and Desroches et al. (31) also compared the standard CO₂ insufflation system with the valveless system used in robotic PN in a prospective randomized trial. The results of our study suggest that the average operative times and, consequently, patient CO₂ exposure and potential adverse outcomes were shorter in the group of patients operated on with the AirSeal® system; when the “zero ischemia” procedure was not feasible, the use of the intelligent insufflation system allowed for less bleeding, especially during the continuous suction phases of tumor resection, improving the visibility of the surgical resection margins and arterial trunk afferents to the tumor, thus selectively controlling them. All of this allowed for late arterial clamping, followed by early unclamping, significantly reducing the “hot ischemia” time. Another advantage is that the removal of parts of the anatomical tissue or the application of gauze and/or hemostatic sponges does not cause any dysfunction of the trocars, since they do not have valves that can fail, as is usually the case with standard trocars, improving the visualization and efficiency of surgical maneuvers, resulting in a reduction in surgical time. In addition, because the valveless trocar system functions at low flow, its use has the potential to reduce cardiopulmonary system compromise from CO₂ insufflation; therefore, the benefits of these trocars can be significant, especially in cases requiring longer operative times or in patients with severe chronic cardiopulmonary disease. AirSeal® was a significant predictor of a shorter operative time (OR 41.09; 95% CI 1.07–1,566.0) without any other influencing factors. Regarding ischemia, a significant negative association has been found with surgery in the polar medial region of the kidney (OR 0.003; 95% CI 9.22e−06–0.98). Furthermore, a longer intervention time was associated with an increased risk of ischemia (OR 1.06; 95% CI 1.00–1.13) (Table 4). There was no significant association with blood transfusion between groups. The preliminary results of our study seem to align with the previous experiences of other authors (Table 5), highlighting that this system can be used to treat even medium-/high-complexity renal lesions, without compromising oncological results. The main limitation of our study is the small sample size. Moreover, although the data were prospectively collected, the analysis was retrospective and, therefore, subject to the inherent limitations of retrospective analyses. Another limitation is the absent secondary analysis of transperitoneal vs. retroperitoneal approach for which we were not warrant.

Although not comparable with studies with a larger number of patients undergoing minimally invasive PN surgery, our preliminary experience has shown that the LPN procedure performed with the aid of the AirSeal® intelligent insufflation system can be used to treat even medium-/high-complexity renal lesions, with a reduction in operating time, “warm ischemia” time, and perioperative blood loss. However, the uniqueness of our study is represented by the fact that for the first time, the advantages of this system were investigated only in the field of laparoscopic partial nephrectomy in renal cell carcinoma. Furthermore, our data investigated the feasibility and safety of an LPN approach using a smart insufflation system.