Does Residual Apical Space (RAS) After Surgery in Persistent/Recurrent Primary Spontaneous Pneumothorax Prove to Be a Predictor Factor of Recurrence? Multicenter Analysis Stratified by Type of Surgery

A. Napolitano¹, M. Sanguigni², E. Coviello³, A. Nocera⁴, J. Vannucci³, D. Nachira⁵, C. Leoni⁵, M. Vita⁵, F. Mucilli⁶, L. Petracca Ciavarella⁵, G. Santoro⁷, M. Congedo⁵, M. Chiappetta⁵, E. Meacci⁵, F. Puma³, F. Lococo⁵, S. Margaritora^8
11 Department of Thoracic Surgery, Fondazione Policlinico Universitario "A.Gemelli" IRCCS, Università Cattolica del Sacro Cuore, 00168 Rome, Rome, Lazio ²Department of Anesthesia and Intensive Care, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Rome, Lazio ³Department of Thoracic Surgery, University of Perugia Medical School, Ospedale Santa Maria della Misericordia, 06134 Perugia, Perugia, Umbria ⁴Department of Thoracic Surgery, Fondazione Policlinico Universitario "A.Gemelli" IRCCS, Università Cattolica del Sacro Cuore, 00168 Rome, Roma, Lazio ⁵Department of Thoracic Surgery, Fondazione Policlinico Universitario "A.Gemelli" IRCCS, Università Cattolica del Sacro Cuore, 00168 Rome, Rome, Lazio ⁶Department of General and Thoracic Surgery, "SS. Annunziata" University Hospital, Via Dei Vestini, 1, 66100, Chieti, Chieti, Abruzzi ⁷Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Catholic University of the Sacred Hearth, Largo Francesco Vito 1, 00168, Rome, Rome, Lazio ⁸Department of Thoracic Surgery, Fondazione Policlinico Universitario "A.Gemelli" IRCCS, Università Cattolica del Sacro Cuore, 00168 Rome, Italy., Rome, Lazio

Purpose: The aim of the study is to evaluate residual apical space (RAS) as a predictor of pneumothorax recurrence in all patients undergoing VATS for persistent/recurrent primary spontaneous pneumothorax (PSP) and stratify its impact for type of surgical treatment.

Methods: A total of 463 patients undergoing VATS for PSP at three thoracic surgery high volume centers (January 2012-March 2023) were retrospectively reviewed. Four types of surgical approaches were analyzed, while the RAS variable was measured by the Collins method at chest-X ray performed at the time before discharge. Although the centers shared essentially the same management in the postoperative period (drainage suction for 48 hours and removal in the absence of air leakage, significant pneumothorax and subcutaneous emphysema), the timing of performing the target radiograph was not entirely homogeneous in the population and RAS was measured at discharge. The following were excluded from the study: secondary forms of pneumothorax, patients < 18 years old, thoracotomy approach. Fisher's and Wilcoxon's association test allowed to evaluate the statistical association between outcome (Collins and Recurrence) and the variables under investigation. Variables with a p-value < 0.05 were considered statistically significant and associated

Results: Tab. 1 exhibits clinical-demographic data and type of surgery associated with recurrence. We recorded no differences in sex, age, smoking and BMI among subgroups. The overall recurrence rate was 6.9% (32 patients) with mean time to recurrence of 62.72±109.37 weeks. Mean hospitalization was 6.5±3.5 days with mean RAS before discharge of Collins 9.7±5.4% (4.2% equivalent to 0 cm RAS). Mechanical pleurodesis alone is associated with a 3.6 higher risk of recurrence (p=0.0027) although associated with significantly lower Collins values (p=0.012), while apicectomy and chemical pleurodesis combined (Fig.1) have a significantly lower risk of recurrence (OR:4.2 p< 0.0001). Overall, an increased RAS (>9.7%) is associated with a higher recurrence rate at the limits of statistical significance (p=0.063). Stratifying the analysis by type of surgery, increased RAS in patients undergoing apicectomy and mechanical pleurodesis is significantly associated with the rate of pneumothorax recurrence (p=0.001-Tab 1).

Conclusion: Data suggest that apicectomy and chemical pleurodesis surgery is the most "protective" for pneumothorax recurrence while RAS value is a predictor factor for recurrence especially in patients undergoing apicectomy with mechanical pleurodesis. RAS postoperative management should take this factor into account to reduce the recurrence rate in the medium to long term period.

Identify the source of the funding for this research project: none