Prolonged air leak (PAL) remains one of the most persistent challenges in thoracic surgery, frequently occurring after pulmonary resections and in the setting of secondary spontaneous pneumothorax (SSP). Despite advances in minimally invasive techniques and perioperative care, PAL continues to be associated with increased morbidity, prolonged hospital stay, and increased healthcare costs (1–3).

According to data from the European Society of Thoracic Surgeons (ESTS) Silver Book database, the incidence of PAL after lobectomy approaches 10% (4) and 15.3% after segmentectomy, as reported in a recent study (5). Moreover, multicenter studies have identified PAL as one of the leading causes of unplanned reinterventions following anatomical lung resection, ranking second only to postoperative haemorrhage and accounting for a substantial proportion of unexpected reoperations (24.4%) (6). In line with these findings, Dezube et al. (7) reported that 16 out of 129 patients who developed PAL after pulmonary resection required surgical reintervention, indicating that approximately 12% of PAL cases fail to resolve with conservative management and ultimately necessitate operative treatment.

Several chronic pulmonary diseases are associated with an increased risk of SSP and PAL (8–11). In this context, pneumothorax represents a clinical manifestation of underlying structural lung abnormalities rather than an isolated event. In selected cases, surgical correction of the air leak is indicated; however, this approach poses a significant challenge due to the heterogeneous and fragile nature of the diseased pulmonary parenchyma (11–13).

Traditionally, surgical management of PAL relied on open thoracotomy, which, although associated with low recurrence rates, entailed significant morbidity, including increased blood loss, postoperative pain, and prolonged hospital stay (14). Consequently, video-assisted thoracic surgery (VATS) has become the preferred approach in current practice. However, despite the advantages of minimally invasive surgery, intraoperative identification of the air leak during reintervention remains technically challenging (15). Conventional techniques, such as the intraoperative water submersion test (iWST), are often difficult to apply in minimally invasive settings, where operative space is limited and adequate lung inflation may be suboptimal. These limitations can compromise precise localization of the air leak and have been associated with higher conversion rates to open surgery.

Ventilation single-photon emission computed tomography combined with computed tomography (vSPECT/CT) has recently emerged as a promising preoperative diagnostic tool for air leak localization (16–18). This technique allows the identification of focal tracer accumulation at the site of air escape, potentially enabling more accurate surgical planning.

Therefore, the present study aims to evaluate the impact of incorporating preoperative vSPECT/CT into the surgical management of patients with PAL by comparing clinical outcomes between patients managed with and without preoperative vSPECT/CT.

Radioventilation was performed using ^99mTc-Technegas delivered via the Venticis® II system. Firing and flushing cycles were carried out according to the manufacturer's specifications using medical-grade argon. Technegas was administered with the patient in a moderately reclined position and nasal airflow occluded. Patients were instructed to perform three to five deep inhalations, each followed by a 5-second Valsalva maneuver.

vSPECT/CT acquisition was performed on a hybrid SPECT/CT system equipped with a low-energy high-resolution collimator. SPECT data were acquired using a body-contouring orbit (128 × 128 matrix, zoom 1.0, 180° rotation, 32 projections, 15 s per projection), followed by a low-dose CT scan for attenuation correction and anatomical localization. SPECT images were reconstructed using an iterative algorithm, both with and without attenuation correction, while CT images were reconstructed as 2-mm axial slices for anatomical co-registration. Image fusion and analysis were performed using dedicated workstation software.

For most patients, vSPECT/CT was performed in the days immediately preceding the planned surgery.

A total of 122 patients were initially included: 52 in the vSPECT/CT group and 70 in the historical non–vSPECT/CT control group. The vSPECT/CT was well tolerated, and no related adverse events were observed. Nine patients (eight with SSP and one with post-resection PAL) were excluded because surgical correction of the air leak was ultimately not performed. In seven patients with SSP, the absence of a clearly detectable air leak combined with a high surgical risk led to deferral of surgery and continuation of conservative management. In the remaining patient, the air leak was localized to a parahilar region, and a non-surgical approach was therefore adopted. In all excluded cases, air leak resolution was achieved spontaneously or following chemical or autologous blood pleurodesis administered through the chest tube. In the post-resection PAL case, although an air leak was identified, it was successfully managed conservatively with autologous blood patch pleurodesis through the chest tube, obviating the need for surgical reintervention. Overall, surgical intervention was avoided in 9 of 52 patients (17.3%) initially evaluated for possible operative management in the vSPECT/CT era.

Following these exclusions, the final vSPECT/CT cohort comprised 43 patients. Baseline demographic and clinical characteristics were comparable between groups, with no clinically relevant differences observed in age, sex distribution, body mass index, or surgical indication.

After optimal 1:1 propensity score matching, 86 patients (43 per group) were analyzed. All covariates, including those not included in the propensity score model, achieved adequate balance, with standardized mean differences below 0.1. Only sex (SMD = 0.14) and BMI (SMD = 0.12) exceeded this threshold, but these differences were considered negligible (Table 1). Figure 2 displays the flow diagram of patient inclusion, vSPECT/CT evaluation, surgical management, and final cohort selection.

PAL remains a common and clinically significant complication following pulmonary resection and SSP, often prolonging hospital stay and increasing healthcare costs. Beyond its direct clinical implications, PAL imposes a substantial burden on patients and healthcare systems, particularly when prolonged drainage fails to achieve spontaneous resolution. Strategies that facilitate accurate localization and definitive surgical treatment of air leaks are therefore of major interest in thoracic surgery. As intraoperative localization of air leaks can be challenging, especially during VATS, preoperative functional imaging may provide added value by guiding targeted surgical intervention.

Our study demonstrates that preoperative vSPECT/CT enables reliable localization of air leaks and is associated with improved postoperative outcomes. In the prospectively enrolled vSPECT/CT cohort, imaging findings showed a high concordance with intraoperative air leak localization (95.3%), facilitating targeted surgical intervention. These findings reflect concordance between imaging-guided localization and surgical exploration rather than formal diagnostic accuracy. Unlike purely anatomical imaging, vSPECT/CT provides functional information on regional ventilation, facilitating precise identification of actively leaking lung segments. To assess the clinical impact of this strategy, we performed propensity score matching incorporating variables known to increase the risk of prolonged air leak after pulmonary resection (22). Importantly, the integration of vSPECT/CT into preoperative planning was associated with a significant reduction in chest tube duration and length of hospital stay compared with matched patients managed without functional imaging guidance.

These findings are consistent with preliminary reports by Krieger et al. (17), which suggested a potential clinical impact of vSPECT/CT, as both total surgical time and incision-to-suture time were shorter following its introduction. In our study, operative time could not be formally assessed for the historical cohort due to the unavailability of operative time data; however, the shorter postoperative course observed in the vSPECT/CT group suggests that improved preoperative localization may enhance overall procedural efficiency.

Minimally invasive approaches were also more frequently employed in the vSPECT/CT group. It should be noted, however, that historical controls were treated during an earlier phase of the institutional VATS learning curve, and the lower VATS rate in this group may reflect evolving surgical expertise rather than the absence of preoperative vSPECT/CT alone. Moreover, a higher proportion of patients in the vSPECT/CT group underwent targeted surgical interventions directed specifically at the site of the air leak. In contrast, in the non–vSPECT/CT cohort, more than 20% of patients were managed with pleural-based procedures alone, without a targeted approach to the underlying source of the air leak. In the initial unmatched cohort, persistent PAL was more frequent following intervention in the non-vSPECT/CT group, highlighting a clinically relevant difference consistent with the expected benefit of targeted leak localization. However, after propensity score matching, these differences were no longer significant, reflecting balanced comparison between groups.

These outcomes suggest that vSPECT/CT facilitates more efficient identification and management of air leaks, leading to faster postoperative recovery. This is particularly relevant in frail patients, for whom prolonged drainage and hospitalization are associated with increased morbidity.

One of the main strengths of this study is the prospective design of the vSPECT/CT cohort, which enabled a structured assessment of its impact on surgical decision-making. Importantly, in a relevant proportion of patients (7/52), vSPECT/CT showed no evidence of an active air leak, supporting a conservative management strategy. In one additional patient, vSPECT/CT localized the air leak to a parahilar region, where surgical correction was considered high risk and therefore avoided. In all these cases, the management strategy guided by vSPECT/CT was not associated with adverse outcomes or 30-day mortality. These findings suggest that vSPECT/CT provides clinically meaningful information not only by enabling targeted surgical intervention, but also by accurately identifying patients in whom surgery can be safely avoided.

Other methods for air leak localization have also been explored. In particular, aerosolized indocyanine green (ICG) inhalation has shown promising results, as it facilitates identification of air leak sites that may be missed with the conventional water submersion test (23, 24). This technique may help reduce postoperative air leaks, particularly in patients undergoing VATS, although it remains investigational and requires further validation in larger clinical studies.

The most recent European consensus (25) emphasizes the importance of a multidisciplinary approach to the management of PAL, the standardization of definitions, and the need for robust evidence-based algorithms to optimize patient outcomes. In this multidisciplinary and algorithm-based context, vSPECT/CT could potentially play a useful complementary role in the assessment and management of PAL.

Despite these encouraging results, several methodological limitations should be acknowledged. First, the absence of a diagnostic gold standard limits formal estimation of accuracy. The iWST itself is an experience-based method of unknown sensitivity and specificity, and obtaining definitive results in thoracoscopic cases remains challenging (26). Additionally, intermittent or temporarily sealed air leaks may not be evident at the time of operation, potentially leading to misclassification of some vSPECT findings. Second, the single-center design and moderate sample size may limit the generalizability of our findings. Third, although propensity score matching was applied, residual confounding due to unmeasured variables cannot be fully excluded. In particular, missing or incomplete data in the retrospective cohort—especially among patients with SPP—limited the inclusion of several clinically relevant covariates in the matching process. This limitation should be considered when interpreting the comparative outcomes.

Finally, because vSPECT/CT was used as a guidance tool during surgery, blinding between imaging findings and intraoperative assessment was not feasible, and observer bias cannot be completely excluded in the interpretation of air leak concordance. Therefore, future prospective, multicenter studies incorporating standardized intraoperative metrics and a multimodal, standardized definition of pulmonary air leak—combining complementary intraoperative techniques and structured postoperative verification—are needed to further define the role of vSPECT/CT in surgical decision-making, explore its predictive value, and refine indications and optimal timing for its use.

In conclusion, preoperative vSPECT/CT is a valuable tool for localizing the origin of PAL, enabling targeted surgical intervention and more precise operative planning. Its use is associated with shorter chest tube duration and hospital stay, supporting its integration into preoperative protocols for patients in the surgical management of PAL.