Abstract
Background
Robot-assisted radical prostatectomy (RARP) requires a stable pneumoperitoneum to maintain optimal surgical conditions. The AirSeal® Intelligent Flow System has been developed to provide continuous pressure regulation and smoke evacuation; however, its clinical impact during RARP remains incompletely defined.
Objective
To compare perioperative, oncological, and postoperative recovery outcomes between the AirSeal system and conventional insufflation systems during RARP.
Methods
We retrospectively analyzed patients who underwent RARP at a high-volume tertiary center in a retrospective before-and-after cohort design. Patients were stratified according to the insufflation system used during surgery: conventional insufflation system (CIS) or the AirSeal system. Demographic characteristics, perioperative parameters, pathological outcomes, postoperative complications (Clavien–Dindo), postoperative pain scores and opioid consumption were evaluated.
Results
A total of 749 patients were included (CIS: 398; AirSeal: 351). Baseline demographic and clinical characteristics were comparable between the groups. Operative time was significantly shorter in the AirSeal group (183 ± 77.7 vs. 217.4 ± 73.0 min; p < 0.001). Estimated blood loss, transfusion rates, and length of hospital stay were similar between the groups.
Pathological stage distribution differed between the groups, with a higher proportion of locally advanced disease (≥pT3) in the AirSeal cohort (49.3% vs 39.2%; p = 0.005). However, other oncological outcomes, including pathological ISUP grade distribution, lymph node involvement, and positive surgical margin rates, were comparable. Overall postoperative complication rates were similar between the groups; however, high-grade complications (Clavien–Dindo ≥III) occurred less frequently in the AirSeal group. Postoperative pain scores at 1, 6, and 24 hours were significantly lower in the AirSeal group (all p < 0.001), postoperative morphine consumption at 24 hours was also significantly reduced (p < 0.001).
Conclusions
Use of the AirSeal insufflation system during RARP was associated with shorter operative times, lower postoperative pain scores, and less frequent high-grade complications. Positive surgical margin rates and lymph node involvement were comparable between the groups. However, given the retrospective before-and-after design, differences in surgical periods and pneumoperitoneum pressure between the groups, these findings should be considered observational and hypothesis-generating.
Supplementary Information
The online version contains supplementary material available at 10.1186/s12894-026-02218-x.
Keywords: Robot-assisted radical prostatectomy, AirSeal insufflation system, Valveless trocar system, Pneumoperitoneum, Postoperative pain, Surgical outcomes
Introduction
Robot-assisted radical prostatectomy (RARP) has become a widely adopted surgical approach for the treatment of localized prostate cancer [1, 2]. The procedure requires the establishment of carbon dioxide pneumoperitoneum and is typically performed in a steep Trendelenburg position. These conditions may lead to several physiological challenges, including increased peak airway pressures, reduced pulmonary compliance, and hemodynamic changes related to impaired venous return and increased systemic vascular resistance [3]. Therefore, maintaining a stable intra-abdominal working space is essential for optimizing surgical performance and patient safety.
To overcome the limitations of conventional insufflation systems, the valveless trocar system (VTS), particularly the AirSeal® Intelligent Flow System, was developed. This integrated system consists of an intelligent flow control unit, a specialized valveless trocar, and a tri-lumen filter tube set. Unlike traditional trocars that rely on mechanical valves to maintain pneumoperitoneum, the AirSeal system uses high-velocity CO₂ flow to create an invisible air barrier at the proximal end of the cannula. Escaping gas is continuously aspirated, filtered to remove surgical smoke and potential contaminants, and recirculated into the peritoneal cavity. This mechanism allows continuous pressure sensing and real-time gas flow adjustments, thereby maintaining a stable pneumoperitoneum throughout the procedure [4, 5].
The valveless design offers several potential advantages in robotic pelvic surgery. Stable pneumoperitoneum can be maintained even during continuous suctioning or minor gas leakage, conditions that may lead to pressure fluctuations when conventional insufflation systems are used [6]. In addition, the absence of a mechanical valve facilitates the unobstructed passage of needles, sutures, and specimens through the trocar channel. Continuous smoke evacuation may also improve visualization of the operative field, which can contribute to improved surgical workflow and operative efficiency [7].
Despite these potential advantages, the clinical impact of valveless insufflation systems during RARP remains incompletely defined. Previous studies have reported variable results regarding operative time, perioperative outcomes, and device-related complications [8]. Therefore, the aim of the present study was to compare perioperative outcomes and operative parameters of robot-assisted radical prostatectomy performed using a valveless trocar system versus a conventional insufflation system.
Materials and methods
Study design and patient selection
This study was designed as a comparative retrospective cohort analysis of patients who underwent RARP for clinically localized prostate cancer between January 2017 and December 2025. The study protocol was approved by the Institutional Review Board (2026.153.IRB2.084), and all procedures were performed in accordance with the ethical standards of the Declaration of Helsinki.
All consecutive patients who met the inclusion criteria during the study period were included in the analysis and divided into two groups according to the insufflation system used during surgery: an AirSeal group and a CIS group. The AirSeal system was introduced into routine clinical practice at our institution in January 2020. Consequently, all RARP procedures performed after this date were carried out using the AirSeal system, whereas procedures performed before January 2020 were conducted using a CIS.
All procedures were performed by experienced surgeons who had each performed more than 500 robotic radical prostatectomy cases prior to the study period. Surgeon distribution between the CIS and AirSeal groups was comparable (Supplementary Table 1). Preoperative staging was performed using multiparametric magnetic resonance imaging (mpMRI) and/or prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) according to institutional protocols.
The inclusion criteria consisted of patients who underwent RARP for clinically localized prostate cancer. Patients with metastatic disease or clinically locally advanced prostate cancer, those who received neoadjuvant hormonal therapy, chemotherapy, or radiotherapy, patients with missing clinical prostate biopsy data, those who underwent concomitant surgical procedures during RARP (such as inguinal hernia repair, bladder diverticulectomy, or ureterolithotomy), and patients undergoing salvage radical prostatectomy were excluded from the analysis.
Surgical technique
All procedures were performed using the da Vinci Xi™ robotic surgical system (Intuitive Surgical, Sunnyvale, CA, USA) with a standard four-arm robotic configuration and one assistant trocar. In the AirSeal group, a 12-mm AirSeal trocar was used as the assistant port, whereas in the CIS group, a 12-mm Covidien trocar was utilized. Pneumoperitoneum was maintained using the AirSeal® Intelligent Flow System (CONMED Corporation, Utica, NY, USA) in the AirSeal group and a conventional insufflation device (Karl Storz SE & Co. KG, Tuttlingen, Germany) in the CIS group. According to institutional practice, pneumoperitoneum pressure was maintained at 12–15 mmHg in the CIS group, whereas procedures in the AirSeal group were performed at either 8 mmHg (n = 127) or 12 mmHg (n = 224). All surgeries were performed using a standardized transperitoneal RARP technique, and surgical techniques and perioperative management protocols remained consistent throughout the study period. Pelvic lymph node dissection was performed in patients classified as intermediate-risk or high-risk according to the European Association of Urology prostate cancer guidelines, and all procedures were performed as extended pelvic lymph node dissection (ePLND) [9].
Data collection and outcome measures
Demographic, clinical, radiological, perioperative, and pathological data were retrospectively collected from the institutional database. Baseline variables included patient demographics, clinical characteristics, and preoperative imaging findings.
Perioperative variables included operative time (trocar insertion to final skin closure), estimated blood loss (EBL), intraoperative blood transfusion requirement, and length of hospital stay. Surgical parameters such as nerve-sparing technique and pelvic lymph node dissection were also recorded.
Oncological outcomes were evaluated based on final pathological findings, including pathological tumor stage (pT), pathological ISUP grade group, lymph node involvement, and positive surgical margin (PSM) status.
Perioperative safety outcomes included postoperative complications occurring within 30 days, classified according to the Clavien–Dindo grading system [10]. Additional perioperative parameters included postoperative pain scores assessed using the Numerical Rating Scale (NRS) and postoperative opioid use.
Postoperative pain management
A standardized institutional postoperative analgesia protocol was uniformly applied to all patients regardless of patient-related factors. Intravenous patient-controlled analgesia (PCA) with morphine was used postoperatively with a 1 mg bolus dose and an 8-minute lockout interval. In addition, paracetamol (1 g three times per day) and ibuprofen (800 mg twice per day) were administered as part of the multimodal analgesic regimen.
Postoperative NRS pain assessments were performed by the same three nurses working in the institutional pain management unit according to standardized postoperative care protocols. The nurses were blinded to group allocation. Pain scores were recorded at the 1st, 6th and 24th postoperative hours. In patients with an NRS score ≥ 7, rescue analgesia with tramadol (1 mg/kg) was administered. Total postoperative opioid consumption was recorded.
Statistical analysis
Statistical analyses were performed using SPSS software (version 22; IBM Corp., Armonk, NY, USA). Continuous variables were presented as mean ± standard deviation (SD) and range, while categorical variables were expressed as frequencies and percentages. The distribution of continuous variables was assessed using the Kolmogorov–Smirnov test.
For comparisons between the two groups, independent samples t-test was used for normally distributed continuous variables, whereas the Mann–Whitney U test was applied for non-normally distributed variables. Categorical variables were compared using the Chi-square test or Fisher’s exact test, as appropriate.
In addition, univariate linear regression analyses were performed to identify variables associated with operative time and high grade complications. Variables with p < 0.1 in univariate analysis were included in the multivariable linear regression model to determine independent predictors.
To further explore the potential impact of temporal bias, subgroup analyses were conducted within each group, and differences in operative time across years were evaluated using analysis of variance (ANOVA). A p-value < 0.05 was considered statistically significant.
Results
A total of 749 patients who underwent RARP were included in the study. Of these, 398 (53.1%) were in the CIS group and 351 (46.9%) in the AirSeal group. The baseline and preoperative characteristics of the patients are presented in Table 1. There were no statistically significant differences between the groups in terms of age, body mass index, American Society of Anesthesiologists (ASA) score (all values p > 0.05). Similarly, preoperative clinical characteristics, including serum prostate-specific antigen (PSA), PSA density, prostate volume, MRI index lesion size, and Prostate Imaging Reporting and Data System (PI-RADS) score, were comparable between the two groups (all p > 0.05).
Table 1.
Baseline demographic, clinical and radiological characteristics of the study population
| Variable | Total (n = 749) | CIS (n = 398) | AirSeal (n = 351) | p value |
|---|---|---|---|---|
| Age (years), mean ± SD (range) | 68.3 ± 7.3 (42–82) | 69.0 ± 10.0 (47–81) | 68.9 ± 8.2 (42–82) | 0.932 |
| Body mass index (kg/m²), mean ± SD (range) | 27.5 ± 3.5 (21–42) | 26.8 ± 3.0 (22–37) | 28.0 ± 3.8 (21–42) | 0.076 |
| ASA score, n (%) | 0.079 | |||
| 1 | 55 (7.3) | 30 (7.5) | 25 (7.1) | |
| 2 | 449 (59.9) | 224 (56.3) | 225 (64.1) | |
| 3 | 245 (32.7) | 144 (36.2) | 101 (28.8) | |
| PSA (ng/mL), mean ± SD (range) | 7.7 ± 5.2 (1.1–49.0) | 7.5 ± 4.8 (1.1–46.0) | 7.8 ± 5.6 (1.2–49.0) | 0.554 |
| PSA density (ng/mL/cm³), mean ± SD (range) | 0.17 ± 0.15 (0.01–2.21) | 0.18 ± 0.17 (0.03–2.21) | 0.17 ± 0.14 (0.01–1.37) | 0.389 |
| Prostate volume on mpMRI (mL), mean ± SD (range) | 52.7 ± 30.5 (13–240) | 51.7 ± 30.7 (13–240) | 53.8 ± 30.5 (16–235) | 0.377 |
| mpMRI index lesion size (mm), mean ± SD (range) | 13.1 ± 6.6 (1–45) | 13.1 ± 6.9 (3–45) | 12.9 ± 6.4 (1–45) | 0.769 |
| PI-RADS score, n (%) | 0.888 | |||
| No MRI | 58 (7.7) | 44 (11.1) | 14 (4.0) | |
| 1 | 6 (0.8) | 2 (0.5) | 4 (1.1) | |
| 2 | 22 (2.9) | 10 (2.5) | 12 (3.4) | |
| 3 | 54 (7.2) | 28 (7.0) | 26 (7.4) | |
| 4 | 396 (52.9) | 203 (51.0) | 193 (55.0) | |
| 5 | 213 (28.4) | 111 (27.9) | 102 (29.1) |
ASA American Society of Anesthesiologists, CIS conventional insufflation systems, mpMRI multiparametric magnetic resonance imaging, PSA prostate-specific antigen, PI-RADS Prostate Imaging Reporting and Data System, SD standard deviation
Oncological outcomes
Pre- and postoperative oncological findings are summarized in Table 2. Biopsy ISUP grade group distribution, D’Amico risk classification, and postoperative ISUP grade were similar between the CIS and AirSeal groups (all p > 0.05). However, pathological stage distribution differed significantly between the groups, with a higher proportion of locally advanced disease (≥ pT3) in the AirSeal group (39.2% vs. 49.3%, p = 0.005). Nerve sparing rates, pelvic lymph node involvement and PSM rates were comparable between the groups (all p > 0.05).
Table 2.
Preoperative and postoperative oncological characteristics of the study population
| Variable | Total (n = 749) | CIS (n = 398) | AirSeal (n = 351) | p value |
|---|---|---|---|---|
| Biopsy ISUP grade group, n (%) | 0.425 | |||
| 1 | 209 (27.9) | 115 (28.9) | 94 (26.8) | |
| 2 | 285 (38.1) | 146 (36.7) | 139 (39.6) | |
| 3 | 136 (18.2) | 76 (19.1) | 60 (17.1) | |
| 4 | 82 (10.9) | 38 (9.5) | 44 (12.5) | |
| 5 | 37 (4.9) | 23 (5.8) | 14 (4.0) | |
| D’Amico risk classification, n (%) | 0.276 | |||
| Low | 194 (25.9) | 105 (26.4) | 89 (25.4) | |
| Intermediate | 403 (53.8) | 221 (55.5) | 182 (51.9) | |
| High | 152 (20.3) | 72 (18.1) | 80 (22.8) | |
| Pathological ISUP grade group, n (%) | 0.964 | |||
| 1 | 87 (11.6) | 44 (11.1) | 43 (12.3) | |
| 2 | 422 (56.3) | 227 (57.0) | 195 (55.6) | |
| 3 | 144 (19.2) | 77 (19.3) | 67 (19.1) | |
| 4 | 29 (3.9) | 14 (3.5) | 15 (4.3) | |
| 5 | 67 (8.9) | 36 (9.0) | 31 (8.8) | |
| RARP pathological stage, n (%) | 0.005* | |||
| pT2 | 420 (56.1) | 242 (60.8) | 178 (50.7) | |
| ≥pT3 | 329 (43.9) | 156 (39.2) | 173 (49.3) | |
| Nerve-sparing, n (%) | 589 (78.6) | 314 (78.9) | 275 (78.3) | 0.855 |
| Pelvic lymph node dissection, n (%) | 429 (58.0) | 221 (56.7) | 208 (59.4) | 0.447 |
| Lymph node involvement, n (%) | 0.223 | |||
| Negative | 375 (87.4) | 189 (85.5) | 186 (89.4) | |
| Positive | 54 (12.6) | 32 (14.5) | 22 (10.6) | |
| Positive surgical margin, n (%) | 0.409 | |||
| Negative | 584 (78.0) | 315 (79.1) | 269 (76.6) | |
| Positive | 165 (22.0) | 83 (20.9) | 82 (23.4) |
Data are presented as number (%)
ISUP International Society of Urological Pathology, CIS conventional insufflation system, RARP Robot assisted radical prostatectomy
* Statistically significant
Operative outcomes
Operative outcomes are presented in Table 3. Operative time was significantly shorter in the AirSeal group compared with the CIS group (183 ± 77.7 vs. 217.4 ± 73.0 min, p < 0.001). On univariate analysis, the use of the AirSeal system, PSA level, index lesion size on MRI, prostate volume, biopsy ISUP grade, EBL, and D’Amico risk classification were significantly associated with operative time. On multivariable analysis, the use of the AirSeal system, lower prostate volume, and lower EBL remained independently associated with shorter operative time (Table 4).
Table 4.
Univariate and multivariable regression analyses of factors associated with operative time
| Variable | Univariate Analysis | Multivariable Analysis | ||
|---|---|---|---|---|
| β (95% CI) | p-value | β (95% CI) | p-value | |
| AirSeal vs. CIS | −33.170 (− 44.241 to − 22.098) | < 0.001 | −34.837 (− 47.243 to − 22.432) | < 0.001 |
| BMI | 1.330 (− 2.021 to 4.682) | 0.433 | ||
| PSA | 1.822 (0.720 to 2.924) | < 0.001 | 0.862 (− 0.574 to 2.299) | 0.239 |
| ASA score | 7.163 (− 2.572 to 16.897) | 0.149 | ||
| D’Amico risk classification | 10.885 (2.588 to 19.183) | 0.010 | −6.515 (− 26.420 to 13.390) | 0.520 |
| mpMRI index lesion size | 1.341 (0.427 to 2.255) | 0.004 | 0.863 (− 0.101 to 1.826) | 0.079 |
| Prostate volume on mpMRI | 0.356 (0.158 to 0.553) | < 0.001 | 0.377 (0.181 to 0.573) | < 0.001 |
| Biopsy ISUP grade | 7.681 (2.695 to 12.667) | 0.003 | 7.402 (− 4.272 to 19.075) | 0.213 |
| Pathological stage ≥pT3 | 10.033 (− 1.360 to 21.425) | 0.084 | ||
| RP ISUP grade | 1.521 (− 3.919 to 6.960) | 0.583 | ||
| EBL | 0.085 (0.044 to 0.126) | < 0.001 | 0.072 (0.024 to 0.120) | 0.004 |
β regression coefficient, CI confidence interval, CIS conventional insufflation system, BMI Body mass index, PSA Prostate specific antigen, ASA American Society of Anesthesiologists, ISUP International Society of Urological Pathology, RP radical prostatectomy, EBL estimated blood loss
Table 3.
Operative outcomes of patients undergoing robot-assisted radical prostatectomy
| Variable | Total (n = 749) | CIS (n = 398) | AirSeal (n = 351) | p value |
|---|---|---|---|---|
| Operative time (min), mean ± SD (range) | 200.7 ± 77.1 (60–600) | 217.4 ± 73.0 (60–580) | 183.0 ± 77.7 (60–600) | < 0.001* |
| EBL (mL), mean ± SD (range) | 157.6 ± 140 (75–1000) | 162.4 ± 161.7 (75–1000) | 152.7 ± 112.1 (100–1000) | 0.320 |
| Blood transfusion, n (%) | 0.083 | |||
| Negative | 736 (98.3) | 348 (97.5) | 348 (99.1) | |
| Positive | 13 (1.7) | 10 (2.5) | 3 (0.9) | |
| Length of hospital stay (days), mean ± SD (range) | 4.19 ± 1.6 (2–17) | 4.3 ± 1.9 (2–17) | 4.0 ± 1.4 (2–14) | 0.107 |
Data are presented as mean ± standard deviation (SD) or number (%)
CIS conventional insufflation system, SD standard deviation, EBL Estimated blood loss
* Statistically significant
To further explore the potential impact of temporal bias, additional analyses were performed within each group. Within the CIS group, operative time did not significantly vary across years (F = 1.369, p = 0.217). Similarly, within the AirSeal group, no significant difference was observed (F = 2.582, p = 0.16).
No significant differences were observed between the CIS and AirSeal groups in terms of estimated blood loss, perioperative blood transfusion, or length of hospital stay (all p > 0.05) (Table 3).
Postoperative complications
Postoperative complications are summarized in Table 5. Overall complication rates were similar between the groups (p = 0.605). When complications were stratified according to severity, high-grade complications (Clavien ≥ III) occurred less frequently in the AirSeal group than in the CIS group (1.4% vs. 4.3%, p = 0.019). Grade 3a complications were mainly related to lymphocele and urinoma requiring percutaneous drainage, whereas Grade 3b complications occurred due to bladder neck contracture requiring endoscopic bladder neck incision. On univariate logistic regression analysis, only the use of the AirSeal system was significantly associated with high-grade complications (Table 6). In addition, year-based comparisons demonstrated no significant difference in high-grade complication rates within either the CIS group (p = 0.492) or the AirSeal group (p = 0.512).
Table 5.
Postoperative complications according to the Clavien–Dindo classification system
| Variable | Total (n = 749) | CIS (n = 398) | AirSeal (n = 351) | p value |
|---|---|---|---|---|
| Clavien–Dindo complications, n (%) | 0.605 | |||
| No complication | 632 (84.4) | 325 (81.7) | 301 (85.8) | |
| Grade 1 | 55 (7.3) | 31 (7.8) | 24 (6.8) | |
| Grade 2 | 46 (6.1) | 25 (6.3) | 21 (6.0) | |
| Grade 3a | 16 (2.1) | 13 (3.3) | 3 (0.9) | |
| Grade 3b | 6 (0.8) | 4 (1.0) | 2 (0.6) | |
| Grade 4 | 0 (0.0) | 0 (0.0) | 0 (0.0) | |
| High-grade complications (Clavien ≥ III), n (%) | 22 (2.9) | 17 (4.3) | 5 (1.4) | 0.019* |
*statistically significant
Table 6.
Univariate logistic regression analysis of factors associated with high-grade complications (Clavien–Dindo ≥ III)
| Variable | Univariate Analysis | |
|---|---|---|
| OR (95% CI) | p-value | |
| AirSeal vs. CIS | 1.127 (1.127 to 8.458) | 0.028 |
| BMI | 0.157 (0.426 to 1.714) | 0.658 |
| PSA | 0.005 (0.915 to 1.082) | 0.907 |
| ASA score | 0.199 (0.584 to 2.549) | 0.597 |
| D’Amico risk classification | 0.078 (0.494 to 1.732) | 0.807 |
| mpMRI index lesion size | 0.029 (0.960 to 1.102) | 0.418 |
| Prostate volume on mpMRI | 0.002 (0.988 to 1.016) | 0.796 |
| Biopsy ISUP grade | 0.035 (0.659 to 1.414) | 0.858 |
| Pathological stage ≥pT3 | 0.325 (0.300 to 1.744) | 0.470 |
| RP ISUP grade | 0.110 (0.762 to 1.635) | 0.574 |
| EBL | 0.001 (0.999 to 1.004) | 0.222 |
β regression coefficient, CI confidence interval, CIS conventional insufflation system, BMI Body mass index, PSA Prostate specific antigen, ASA American Society of Anesthesiologists, ISUP International Society of Urological Pathology, RP radical prostatectomy, EBL estimated blood loss
Postoperative pain scores and opioid consumption
NRS pain scores were significantly lower in the AirSeal group than in the CIS group at postoperative hours 1, 6, and 24 (all p < 0.001). Morphine consumption was similar between the groups at postoperative hours 1 and 6, whereas morphine consumption at postoperative hour 24 was significantly lower in the AirSeal group (p < 0.001) (Table 7).
Table 7.
Postoperative pain scores (NRS) and opioid consumption
| Variable | Total (n = 749) | CIS (n = 398) | AirSeal (n = 351) | p value |
|---|---|---|---|---|
| NRS pain score, mean ± SD | ||||
| Postoperative hour 1 | 4.6 ± 2.4 | 5.1 ± 2.3 | 4.2 ± 2.6 | < 0.001* |
| Postoperative hour 6 | 3.8 ± 2.1 | 4.2 ± 2.3 | 3.4 ± 1.9 | < 0.001* |
| Postoperative hour 24 | 2.0 ± 1.0 | 2.2 ± 1.1 | 1.8 ± 0.9 | < 0.001* |
| Morphine consumption (mg), mean ± SD | ||||
| Postoperative hour 1 | 6.1 ± 3.8 | 6.3 ± 3.4 | 5.9 ± 4.3 | 0.16 |
| Postoperative hour 6 | 10.7 ± 6.5 | 11.1 ± 5.8 | 10.3 ± 7.2 | 0.09 |
| Postoperative hour 24 | 19.0 ± 10.3 | 22.2 ± 10.5 | 15.3 ± 9.1 | < 0.001* |
NRS Numerical Rating Scale, SD standard deviation, CIS conventional insufflation system
*statistically significant
Discussion
Our study, evaluating the impact of the AirSeal insufflation system in patients undergoing RARP, revealed noteworthy findings.
First, we found a significantly shorter operative time in the AirSeal group. This finding is consistent with recent meta-analyses and individual cohort studies that have identified the AirSeal system as an independent predictor of reduced surgical duration [8, 11]. The technical advantages of the valveless design provide a logical explanation for this improvement in operative efficiency. Conventional trocars utilize mechanical valves that must be manipulated for the passage of sutures, needles, and specimens, often leading to sudden loss of pneumoperitoneum [6, 12]. In contrast, the AirSeal system uses a high-velocity CO₂ air barrier that allows the unimpeded passage of instruments and tissue while maintaining stable intra-abdominal pressure [6, 11, 13, 14]. Furthermore, the continuous smoke evacuation and filtration provided by the system prevent the accumulation of surgical plume and reduce the frequency of camera smudging, thereby decreasing the need for intraoperative lens cleaning [8, 12, 15]. These cumulative micro-efficiencies may have contributed to the shorter operative time observed in our cohort [8, 11].
Second, perioperative oncological findings regarding PSM rates and lymph node involvement were comparable between the groups despite the higher proportion of patients with locally advanced disease (≥ pT3) in the AirSeal group. Nevertheless, these findings should be interpreted cautiously given the retrospective design and the imbalance in pathological stage distribution between the groups. Existing literature generally demonstrates comparable PSM rates and lymph node involvement between the AirSeal system and CIS. In a cohort study by George et al., PSM rates were 26.3% in the AirSeal group and 24.1% in the conventional group, with no statistically significant difference between them (p = 0.548) [11]. Similarly, Otaola-Arca et al. reported nearly identical PSM rates of 14.7% for the AirSeal group and 14.6% for the conventional group (p = 0.893) [13]. Ayoub et al. further reported no significant differences in surgical margin involvement (p = 0.111) or biochemical recurrence (BCR) rates (p = 0.411) between the two systems [15]. These findings are supported by recent meta-analytic data demonstrating comparable PSM rates and lymph node involvement between the AirSeal system and CIS [8].
Third, in terms of perioperative safety, our findings regarding EBL and blood transfusion rates are consistent with previous studies in the literature. For instance, George et al. reported an EBL of 256.6 mL in the AirSeal group compared to 223.6 mL in the CIS group, with transfusion rates at 0.5% and 0.8%, respectively [11]. Similarly, Ayoub et al. found no statistically significant difference in EBL (270 mL vs. 235.5 mL) or transfusion requirements (0.8% vs. 1.5%) when comparing AirSeal and CIS [15]. These observations are further supported by Otaola-Arca et al., who reported comparable EBL (366.5 mL vs. 394.8 mL) and very low transfusion rates (0.6% vs. 0.7%) between the two groups [13].
Theoretically, the maintenance of a stable pneumoperitoneum and the system’s ability to rapidly compensate for pressure loss during suctioning may help maintain consistent visualization during critical steps such as dissection of the dorsal venous complex and neurovascular bundles [6, 13]. However, our findings, together with other clinical evaluations, suggest that these technical advantages may be more closely associated with improved surgical workflow and operative efficiency than with measurable differences in total blood loss [6, 15].
In our cohort, the length of hospital stay was comparable between the groups. However, several studies have reported shorter hospitalization with valveless insufflation systems.A recent meta-analysis including 1,503 patients demonstrated a modest but significant reduction in hospital stay in the AirSeal group (WMD − 0.45 days) [8]. Similarly, Ayoub et al. reported a decrease in length of stay from 2.0 to 1.51 days, while Otaola-Arca et al. also observed shorter hospitalization in the AirSeal cohort [13, 15]. The lack of a significant difference in length of hospital stay in our study may be influenced by cultural factors and differences in healthcare systems, as patients in some settings may prefer longer hospitalization despite clinical readiness for discharge.
Regarding postoperative morbidity, overall complication rates were similar between the two groups in our cohort. However, when complications were stratified according to severity, high-grade complications (Clavien–Dindo ≥ III) occurred less frequently in the AirSeal group than in the CIS group. These findings are in line with previous studies evaluating valveless insufflation systems in robotic surgery. For instance, Otaola-Arca et al. reported a significantly lower major complication rate in the AirSeal group compared with the CIS group (0.6% vs. 4.2%, p < 0.05) [13]. Similarly, the meta-analysis by Zhi et al. demonstrated that the AirSeal system was associated with fewer major complications than conventional systems (OR 0.15, p = 0.01) [8]. Ayoub et al. also reported significantly lower odds of Grade > II complications in the AirSeal group (OR = 0.102, p < 0.022) [15]. These observations suggest that the technical characteristics of the Airseal system may be associated with lower rates of major complications in robotic pelvic surgery.
Fourth, postoperative pain scores and analgesic requirements were lower in the AirSeal group in our cohort. NRS pain scores were significantly lower at postoperative hours 1, 6, and 24, and opioid consumption at 24 h was also significantly reduced in patients operated on with the AirSeal system. Our findings are further corroborated by Shahait et al., who demonstrated significantly lower pain intensity in the VTS group during the first 18 h (e.g., 1.9 vs. 2.5 at 0–6 h, p = 0.034) [12]. Similarly, Ayoub et al. reported that the AirSeal system reduced the odds of opioid requirement by nearly 50% (OR = 0.49, p = 0.024), with actual usage rates of 12% compared to 21.9% in conventional cases [15]. Furthermore, Buhas et al. indicated that AirSeal patients achieve an analgesic-free status much earlier, with 100% of patients stopping painkillers by postoperative day 8 compared to only 83% by day 14 in standard insufflation groups [16].
Several physiological mechanisms may potentially explain these observations. The AirSeal system enables the maintenance of adequate surgical exposure even at lower intra-abdominal pressures (typically 8–10 mmHg compared to the conventional 12–15 mmHg range) [17, 18]. Lower pressures may reduce peritoneal stretching and diaphragmatic irritation, which are known contributors to postoperative shoulder and abdominal pain [19]. In addition, stable pneumoperitoneum and reduced pressure fluctuations may be associated with less diaphragmatic irritation and phrenic nerve stimulation [20].
Importantly, the difference in pneumoperitoneum pressure between the groups may also have contributed to the observed differences in postoperative pain and analgesic requirements. Since our study did not compare the two insufflation systems under identical pressure settings, the independent effect of the AirSeal system on postoperative pain cannot be fully determined. Nevertheless, the ability of the AirSeal system to provide adequate surgical exposure at lower pressures may represent a potentially relevant factor associated with postoperative pain outcomes in our cohort.
Study limitations
Despite its strengths, this study has several limitations. First, its retrospective design may introduce inherent selection bias. Second, the study was conducted at a single high-volume center, which may limit the generalizability of the findings. Third, group allocation was determined by the time period of surgery, as the AirSeal system was introduced during the study period, resulting in potential temporal (historical) bias. Changes in surgical experience, perioperative management, and institutional practices over time may have influenced the observed outcomes independently of the insufflation system. However, all procedures were performed by the same four highly experienced robotic surgeons, each of whom had performed more than 500 RARP procedures prior to the study period, and surgical techniques and perioperative management protocols remained consistent throughout the study period. Furthermore, no significant variation in operative time or high-grade complication rates across years was observed within either group.
Another limitation is that the AirSeal group included a higher proportion of patients with locally advanced disease (≥ pT3), which may have increased operative complexity. However, pathological stage was not independently associated with operative time or high-grade complications.
The study primarily evaluated short-term perioperative outcomes and did not assess long-term oncological or functional results such as biochemical recurrence, urinary continence, or erectile function. In addition, a formal cost analysis was not performed. Prospective randomized studies evaluating long-term functional and oncological outcomes are needed to further clarify the clinical impact and cost-effectiveness of the AirSeal system in robot-assisted radical prostatectomy.
Conclusion
In conclusion, the use of the AirSeal system during RARP was associated with shorter operative times, lower postoperative pain scores, and less frequent high-grade complications in our cohort. Perioperative oncological parameters, including PSM rates and lymph node involvement, were comparable between the groups. However, given the retrospective before-and-after design, differences in surgical periods and pneumoperitoneum pressure between the groups, and the limited number of major complications, these findings should be considered observational and hypothesis-generating. Further prospective studies are warranted to better define the clinical and economic implications of valveless insufflation systems in robotic urologic surgery.
Supplementary Information
Acknowledgments
Clinical trial number
not applicable.
Authors' contributions
I.C.A. conceived and designed the study, and wrote the main manuscript. M.M., S.K.M., A.G., and E.K. contributed to data collection. A.O. performed the formal statistical analysis. Y.K. and M.D.B. contributed to manuscript review and editing. T.E. and A.E.C. supervised the study and critically revised the manuscript. All authors reviewed and approved the final manuscript.
Funding
The funder had no role in the design, data collection, data analysis, and reporting of this study.
Data availability
The datasets generated and/or analyzed during the current study are not publicly available due to ethical restrictions imposed by the approval of the Koç University Clinical Research Ethics Committee, as the data contain sensitive patient information. Data may be made available from the corresponding author upon reasonable request and with additional approval from the relevant ethics committee.
Declarations
Ethics approval and consent to participate
This study protocol was reviewed and approved by the Koç University Clinical Research Ethics Committee (Koç University, Istanbul, Türkiye), with approval number (2026.153.IRB2.084). The study was conducted in accordance with the principles of the Declaration of Helsinki and relevant institutional guidelines.
Due to the retrospective nature of the study, written informed consent for participation was waived by the Koç University Clinical Research Ethics Committee (Koç University, Istanbul, Türkiye). All patients had previously provided written consent allowing the use of their anonymized clinical data for academic and scientific research purposes.
Consent for publication
Not applicable.
Competing interests
The authors declare no competing interests.
Footnotes
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Data Availability Statement
The datasets generated and/or analyzed during the current study are not publicly available due to ethical restrictions imposed by the approval of the Koç University Clinical Research Ethics Committee, as the data contain sensitive patient information. Data may be made available from the corresponding author upon reasonable request and with additional approval from the relevant ethics committee.