ORIGINAL ARTICLE – THORACIC

Interactive CardioVascular and Thoracic Surgery 20 (2015) 647–653 doi:10.1093/icvts/ivv022 Advance Access publication 16 February 2015

Cite this article as: Imperatori A, Rotolo N, Spagnoletti M, Festi L, Berizzi F, Di Natale D et al. Risk factors for postoperative recurrence of spontaneous pneumothorax treated by video-assisted thoracoscopic surgery. Interact CardioVasc Thorac Surg 2015;20:647–53.

Andrea Imperatori*, Nicola Rotolo, Marco Spagnoletti, Luigi Festi, Fabio Berizzi, Davide Di Natale, Elisa Nardecchia and Lorenzo Dominioni Center for Thoracic Surgery, University of Insubria, Ospedale di Circolo, Varese, Italy * Corresponding author. Center for Thoracic Surgery, University of Insubria, Via Guicciardini, 9, 21100 Varese, Italy. Tel: +39-0332-278868; fax: +39-0332-260260; e-mail: [email protected] (A. Imperatori). Received 13 September 2014; received in revised form 5 January 2015; accepted 14 January 2015

Abstract OBJECTIVES: Over the past two decades, video-assisted thoracoscopic blebectomy and pleurodesis have been used as a safe and reliable option for treatment of spontaneous pneumothorax. The aim of this study is to evaluate the long-term outcome of video-assisted thoracoscopic surgery (VATS) treatment of spontaneous pneumothorax in young patients, and to identify risk factors for postoperative recurrence. METHODS: We retrospectively analysed the outcome of VATS treatment of spontaneous pneumothorax in our institution in 150 consecutive young patients (age ≤40 years) in the years 1997–2010. Treatment consisted of stapling blebectomy and partial parietal pleurectomy. After excluding 16 patients lost to follow-up, in 134 cases [110 men, 24 women; mean age, 25 ± 7 standard deviation years; median followup, 79 months (range: 36–187 months)], we evaluated postoperative complications, focusing on pneumothorax recurrence, thoracic dysaesthesia and chronic chest pain. Risk factors for postoperative pneumothorax recurrence were analysed by logistic regression. RESULTS: Of 134 treated patients, 3 (2.2%) required early reoperation (2 for bleeding; 1 for persistent air leaks). Postoperative (90-day) mortality was nil. Ipsilateral pneumothorax recurred in 8 cases (6.0%) [median time of recurrence, 43 months (range: 1–71 months)]. At univariate analysis, the recurrence rate was significantly higher in women (4/24) than in men (4/110; P = 0.026) and in patients with >7-day postoperative air leaks (P = 0.021). Multivariate analysis confirmed that pneumothorax recurrence correlated independently with prolonged air leaks (P = 0.037) and with female gender (P = 0.045). Chronic chest wall dysaesthesia was reported by 13 patients (9.7%). In 3 patients, (2.2%) chronic thoracic pain (analogical score >4) was recorded, but only 1 patient required analgesics more than once a month. CONCLUSIONS: VATS blebectomy and parietal pleurectomy is a safe procedure for treatment of spontaneous pneumothorax in young patients, with a 6% long-term recurrence rate in our experience. Postoperative recurrence significantly correlates with female gender and with prolonged air leakage after surgery. Keywords: Spontaneous pneumothorax • Video-assisted thoracoscopic surgery • Blebectomy • Partial parietal pleurectomy • Postoperative recurrence • Risk factors

INTRODUCTION Spontaneous pneumothorax (SP) predominantly occurs in healthy, young, tall and thin males [1]. It is a relevant health problem, with incidence of 18–28/100 000 cases per year in men and 1.2–6/100 000 in women [1]. After the first SP episode, the estimated recurrence rate is 23–50% and it increases up to 60% after further episodes [1]. Primary SP is usually caused by rupture of sub-pleural blebs or bullae, in patients with no evidence of other underlying lung disease, although histological abnormalities are usually present. In contrast, secondary pneumothorax usually occurs in patients with overt underlying lung disease, most † Presented at the 28th Annual Meeting of the European Association for CardioThoracic Surgery, Milan, Italy, 11–15 October 2014.

commonly chronic obstructive pulmonary disease (COPD) and emphysema [1]. Active smoking habit has been identified as a risk factor for SP development [1]. The optimal treatment, both at first pneumothorax episode and at recurrence, has been a matter of debate. Non-surgical conservative treatment with intercostal needle aspiration or tube drainage is safe, but carries a high rate of recurrences that predominantly occur within the first 2 years [1]. Surgical treatment is needed in 25–50% of all patients suffering from SP, because of persistent air leak or a subsequent episode [1]. The objective of surgical repair of pneumothorax is two-fold: firstly, to resect the visible pleural bullae or blebs responsible for persistent air leak; secondly, to obtain pleurodesis of parietal and visceral pleural surfaces. Open thoracotomy with resection of bullae and pleural abrasion was the original surgical treatment; however, over the past two decades, less invasive video-assisted

© The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

ORIGINAL ARTICLE

Risk factors for postoperative recurrence of spontaneous pneumothorax treated by video-assisted thoracoscopic surgery†

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A. Imperatori et al. / Interactive CardioVascular and Thoracic Surgery

thoracoscopic procedures have been adopted. Meta-analyses comparing thoracotomy with video-assisted thoracoscopic surgery (VATS) procedures for treatment of pneumothorax have shown lower recurrence rates (1%) with open procedures [2, 3] but these are associated with greater blood loss, significantly greater postoperative pain and longer hospital stay [4]. Nowadays, VATS bullectomy and pleurodesis is widely accepted as a safe and reliable option for treatment of recurrent pneumothorax [1, 5, 6]. The pneumothorax recurrence rate after VATS treatment has been reported to range from 0 to 11% using different pleurodesis techniques [5, 7–15]. Identified risk factors for postoperative recurrence of SP include age 7 days (yes versus no)

1.01 5.30 0.88 1.13 4.76 0.75 0.75 0.59 0.87

0.92–1.12 1.22–22.96 0.63–1.23 0.26–4.95 0.57–39.87 0.17–3.27 0.18–3.13 0.14–2.49 0.17–4.50

0.824 0.026 0.461 0.868 0.150 0.702 0.693 0.477 0.865

1.72 3.50 5.63

0.39–7.51 0.82–14.89 1.30–24.48

0.470 0.090 0.021

OR: odds ratio; CI: confidence interval; VATS: video-assisted thoracoscopic surgery.

ORIGINAL ARTICLE

medcalc.org; 2014). Univariate and multivariate logistic regression analysis was used to analyse postoperative recurrence risk factors. Cox regression analysis was carried out to check univariate and multivariate models (Supplementary Tables 2 and 3). We included all factors into the multivariable model with a P-value 7 days. Differences were considered statistically significant with a P-value 7 days (yes versus no)

4.72 5.03

1.04–21.46 1.11–22.89

0.045 0.037

OR: odds ratio; CI: confidence interval.

patients underwent blebectomy or lung apicectomy by VATS lung wedge resection with mechanical stapler and in all cases partial parietal pleurectomy for pleurodesis was associated, to reduce pneumothorax recurrence risk. Over a 79-month median followup, the recurrence rate in our series was 6.0%, in line with recurrence rates reported in the literature (0–11%), summarized in Table 5. In our study, postoperative morbidity occurred in 23.7% of patients, more frequently than observed in other series [8, 10, 16]; however, most complications were of minor entity and predominantly consisted of prolonged air leakage (17.2%). Lang-Lazdunski reported a similar rate of persistent air leakage (14.8%), using a different pleurodesis method ( pleural abrasion) [5]. Nevertheless, the high incidence of air leaks in our series is of concern. There are no obvious explanations for this high rate. Our surgical technique is similar to that described by others [18], air leakage test is performed routinely, and our indication for chest tube removal is generally conservative. Furthermore, the learning curve is not a likely explanation for our results, because over the long period of this study junior surgeons had prolonged air leak rates similar to those of seniors (18.9 vs 16.5%). These differences could be explained by overlooked leaking bullae, as air leakage tests are sometimes difficult to interpret during VATS. Multivariate analysis showed that, in our series, the late recurrence of ipsilateral pneumothorax, with a median interval of 43 months from VATS treatment, correlated independently with prolonged air leaks (P = 0.037) and with female gender (P = 0.045). The existence of ‘catamenial’ pneumothorax (CP), defined as pneumothorax recurring at the onset of menses, is debated [22]. There are about 250 CP cases described in the literature, but the aetiology of CP is unclear. Thoracoscopic inspection in these cases often showed small diaphragmatic ‘fenestrated’ areas, likely to be islands of endometrial deposits responsible for the pneumothorax recurring during menstrual cycle [1, 22]. In our study, we observed 4 women with pneumothorax recurrence after VATS treatment. Three of them also presented with pelvic endometriosis and in 2 of these cases, we observed small diaphragmatic ‘fenestrations’ during VATS inspection. These findings underscore the need of carefully exploring the pleural cavity and the diaphragm in young women undergoing VATS treatment of pneumothorax. Pleural lesions suspicious of endometriosis should be biopsied and hormonal treatment should be considered.

Table 5: Pneumothorax recurrence rate after VATS with different pleurodesis techniques Author

Year

Patients

Follow-up (months)

Recurrence rate (%)

Pleurodesis technique

Kim et al. [7] Gossot et al. [8] Lang-Lazdunsky et al. [5] Margolis et al. [9] Cardillo et al. [10] Waller et al. [11] Ayed et al. [12] Cardillo et al. [13] Chen et al. [14] Park et al. [15] Imperatori et al. a

1996 2003 2003 2003 2006 1994 2000 2001 2009 2012 2014

36 111 167 156 805 60 30 432 978 165 134

24 36 84 62 52 62 36 38 47 56 79

11.1 3.6 3.0 0.0 1.7 6.7 10.0 4.4 5.4 7.3 6.0

Abrasion Abrasion Abrasion Talc Talc Pleurectomy Pleurectomy Pleurect./talc Pleurect./abr. Pleurect./abr. Pleurectomy

VATS: video-assisted thoracoscopic surgery. a Present study.

In our study, the postoperative recurrences did not show a significant relationship with smoking habit, as reported by other authors [10], possibly because smoking exposure in our cohort was limited, as suggested by low median pack-years. Regarding the other end-points of our study, we found 2.2% of patients with postoperative chronic pain and 9.7% with dysaesthesia, both rates being lower than generally reported in the literature: chronic pain, up to 30% [5, 23, 24]; dysaesthesia, up to 50% [24, 25]. However, the rates of these complications are difficult to compare because their definition is not uniform and data collection methods vary. There are limitations to the present study. This is a single-centre study, with a retrospective design, although the data have been prospectively collected since 1997 under regular revision by a data manager. Points of strength are the consecutive series and a uniform mode of pneumothorax management by VATS throughout the study, by the same surgical team. Of note is also the longterm follow-up in our study, because half of recurrences were detected after more than 4 years from surgery. In conclusion, our findings confirm that VATS blebectomy with pleurectomy for pleurodesis is a safe and effective procedure for treatment of SP in young patients. Postoperative recurrence significantly correlates with female gender and with prolonged air leakage after surgery. Further efforts should be made, aiming to improve postoperative air leak control.

SUPPLEMENTARY MATERIAL Supplementary material is available at ICVTS online. Conflict of interest: none declared.

REFERENCES [1] MacDuff A, Arnold A, Harvey J; BTS Pleural Disease Guideline Group. Management of spontaneous pneumothorax: British Thoracic Society Pleural Disease Guideline 2010. Thorax 2010;65(Suppl 2):18–31. [2] Barker A, Maratos EC, Edmonds L, Lim E. Recurrence rates of videoassisted thoracoscopic versus open surgery in the prevention of recurrent pneumothorax: a systematic review of randomised and non-randomised trials. Lancet 2007;370:329–35. [3] Vohra HA, Adamson L, Weeden DF. Does video-assisted thoracoscopic pleurectomy result in better outcomes than open pleurectomy for primary spontaneous pneumothorax? Interact CardioVasc Thorac Surg 2008;7:673–7. [4] Sedrakyan A, van der Meulen J, Lewsey J, Treasure T. Video assisted thoracic surgery for treatment of pneumothorax and lung resections: systematic review of randomised clinical trials. BMJ 2004;329:1008. [5] Lang-Lazdunski L, Chapuis O, Bonnet PM, Pons F, Jancovici R. Videothoracoscopic bleb excision and pleural abrasion for the treatment of primary spontaneous pneumothorax: long term results. Ann Thorac Surg 2003;75:960–5. [6] Goto T, Kadota Y, Mori T, Yamashita SI, Horio H, Nagayasu T et al. Videoassisted thoracic surgery for pneumothorax: republication of a systematic review and a proposal by the guideline committee of the Japanese Association for Chest Surgery 2014. Gen Thorac Cardiovasc Surg 2015;63:8–13. [7] Kim KH, Kim HK, Han JY, Kim JT, Won YS, Choi SS. Transaxillary minithoracotomy versus video-assisted thoracic surgery for spontaneous pneumothorax. Ann Thorac Surg 1996;61:1510–2. [8] Gossot D, Galetta D, Stern JB, Debrosse D, Caliandro R, Girard P et al. Results of thoracoscopic pleural abrasion for primary spontaneous pneumothorax. Surg Endosc 2004;18:466–71. [9] Margolis M, Gharagozloo F, Tempesta B, Trachiotis GD, Katz NM, Alexander P. Video-assisted thoracic surgical treatment of initial spontaneous pneumothorax in young patients. Ann Thorac Surg 2003;76:1661–4.

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[10] Cardillo G, Carleo F, Giunti R, Carbone L, Mariotta S, Salvadori L et al. Videothoracoscopic talc poudrage in primary spontaneous pneumothorax: a single-institution experience in 861 cases. J Thorac Cardiovasc Surg 2006; 131:322–8. [11] Waller DA, Forty J, Morritt G. Video-assisted thoracoscopic surgery versus thoracotomy for spontaneous pneumothorax. Ann Thorac Surg 1994;58: 372–6. [12] Ayed AK, Al-Din HJ. Video-assisted thoracoscopy versus thoracotomy for primary spontaneous pneumothorax: a randomized controlled trial. Med Princ Pract 2000;9:113–8. [13] Cardillo G, Facciolo F, Regal M, Carbone L, Corzani F, Ricci A et al. Recurrences following videothoracoscopic treatment of primary spontaneous pneumothorax: the role of redo-videothoracoscopy. Eur J Cardiothorac Surg 2001;19:396–9. [14] Chen JS, Hsu HH, Kuo SW, Huang PM, Lee JM, Lee YC. Management of recurrent primary spontaneous pneumothorax after thoracoscopic surgery: should observation, drainage, redo thoracoscopy, or thoracotomy be used? Surg Endosc 2009;23:2438–44. [15] Park JS, Han WS, Kim HK, Choi YS. Pleural abrasion for mechanical pleurodesis in surgery for primary spontaneous pneumothorax: is it effective? Surg Laparosc Endosc Percutan Tech 2012;22:62–4. [16] Uramoto H, Shimokawa H, Tanaka F. What factors predict recurrence of a spontaneous pneumothorax? J Cardiothorac Surg 2012;7:112. [17] Ingolfsson I, Gyllstedt E, Lillo-Gil R, Pikwer A, Jönsson P, Gudbjartsson T. Reoperations are common following VATS for spontaneous pneumothorax: study of risk factors. Interact CardioVasc Thorac Surg 2006;5:602–7. [18] Inderbitzi RG, Leiser A, Furrer M, Althaus U. Three years experience in video-assisted thoracic surgery (VATS) for spontaneous pneumothorax. J Thorac Cardiovasc Surg 1994;107:1410–5. [19] Muramatsu T, Nishii T, Takeshita S, Ishimoto S, Morooka H, Shiono M. Preventing recurrence of spontaneous pneumothorax after thoracoscopic surgery: a review of recent results. Surg Today 2010;40:696–9. [20] Kim DH. The feasibility of axial and coronal combined imaging using multidetector row computed tomography for the diagnosis and treatment of a primary spontaneous pneumothorax. J Cardiothorac Surg 2011;6:71. [21] Bille A, Barker A, Maratos EC, Edmonds L, Lim E. Surgical access rather than method of pleurodesis ( pleurectomy or pleural abrasion) influences recurrence rates for pneumothorax surgery: systematic review and meta-analysis. Gen Thorac Cardiovasc Surg 2012;60:321–5. [22] Rousset-Jablonski C, Alifano M, Plu-Bureau G, Camilleri-Broet S, Rousset P, Regnard JF et al. Catamenial pneumothorax and endometriosis-related pneumothorax: clinical features and risk factors. Hum Reprod 2011;26: 2322–9. [23] Passlick B, Born C, Sienel W, Thetter O. Incidence of chronic pain after minimal-invasive surgery for spontaneous pneumothorax. Eur J Cardiothorac Surg 2001;19:355–8. [24] Jutley RS, Khalil MW, Rocco G. Uniportal vs. standard three-port VATS technique for spontaneous pneumothorax: comparison of post-operative pain and residual paraesthesia. Eur J Cardiothorac Surg 2005;28:43–6. [25] Sihoe AD, Au SS, Cheung ML, Chow IK, Chu KM, Law CY et al. Incidence of chest wall paresthesia after video-assisted thoracic surgery for primary spontaneous pneumothorax. Eur J Cardiothorac Surg 2004;25: 1054–8.

APPENDIX. CONFERENCE DISCUSSION Scan to your mobile or go to http://www.oxfordjournals.org/page/6153/1 to search for the presentation on the EACTS library

Dr O. Fanucchi (Pisa, Italy): Did your patients undergo an apicoectomy also in the case of normal lung tissue such as in Vanderschuren Class I? And the second question is: in your paper you say that four of the eight patients who had recurrent pneumothorax after VATS treatment were female and that three of them had endometriosis. Were these patients treated with hormonal therapy, so was the final diagnosis a catamenial pneumothorax? Dr Imperatori: I did not report in this presentation due to short time, but apicoectomy was always performed. Final pathological examination demonstrated that also in patients with no evidence of blebs or bullae, the apex of the lung was dystrophic. We perform in 100% of our cases an apicoectomy by VATS stapling.

ORIGINAL ARTICLE

A. Imperatori et al. / Interactive CardioVascular and Thoracic Surgery

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A. Imperatori et al. / Interactive CardioVascular and Thoracic Surgery

Regarding the second question, this is another key point. You are right, in the analysis of our data, three out of four female patients with recurrence had endometriosis, and in two of these, we were able to detect intraoperatively by inspection of the diaphragm the typical brown fenestration. These two patients underwent hormonal therapy. Unfortunately, just in one case we were able to show pathologically that this was a site of endometriosis. The other case was just necrotic tissue, probably because we were in the menstrual period of the patient. In conclusion, it’s very important to focus on a correct inspection of the diaphragm before performing VATS surgery for pneumothorax in young women. Dr G. Cardillo (Rome, Italy): I have a short question for you. All of us know that the key point for recurrence prevention is the pleurodesis, not the bullectomy. Recurrence rate showed 6%. In my opinion that is too high, so try to reconsider the partial pleurectomy, which seems not enough for recurrence prevention in light of your 6% recurrence rate. Can you comment on that? Dr Imperatori: You are right. This study enrolled patients until 2010, and we retrospectively evaluated our data. We are now considering performing, when possible, talc poudrage for pleurodesis. This could be the solution to avoid basal recurrence and to let the drainage for a shorter time. Moreover, it could reduce the postoperative air leakage that could be due to an incomplete resection of the bullae or when stapling lung resection falls on dystrophic tissue. Dr A. Sihoe (Hong Kong, China): Just two very quick questions. First point, you mentioned a lot of patients had recurrence quite late, and I think that’s something that we’re starting to realize all around the world. So, in the future, instead of just reporting a recurrence rate after an average of so many months, don’t you think it’s actually more appropriate that we do a survival analysis to study recurrences? The second question is: most studies on recurrence after surgery tend to focus on patient factors like female, age and also intraoperative factors. But I think points that we’re neglecting are the postoperative factors, how much pain the patient is in, what analgesia they’re given, how much suction we apply, is there an appearance of a rim of air after we remove the chest tubes? Did you consider looking at these factors? Dr Imperatori: For the first question, I agree with you. Late recurrence is very important because if we had completed our follow-up after four years, as reported in several studies, we would have lost 50% of recurrence in our centre, and we could show a 3% recurrence rate. For the suggested survival analysis, it could not be the right approach because recurrence is usually a rare event. The second point is pain. As I briefly showed you, we had 10% of ipsilateral chest wall dysaesthesia and only 2.2% of chronic pain, and these did not correlate with recurrence in our experience. Dr Sihoe: It’s not just pain, though. It’s a multitude of postoperative factors. How we treat the patient after surgery might have some bearing on future occurrence, don’t you think? Dr Imperatori: It could be, but we postoperatively recorded a pain VAS in all patients. We do not have a very high mean VAS score, and this did not correlate with recurrence in our experience. Postoperative pain treatment was usually with analgesic drugs usually per os ( paracetamol) and exceptionally with intravenous drugs, so I don’t think this could be the main point.

eComment. Innovation for minimally invasive surgical treatment of pneumothorax Authors: Pietro Bertoglio, Stylianos Korasidis and Marcello C. Ambrogi Dept of Surgical Medical Molecular Pathology and Critical Care, University of Pisa, Pisa, Italy doi: 10.1093/icvts/ivv102 © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved. I read the interesting article by Imperatori and his coworkers [1]. Pneumothorax can be considered as one of the most common diagnosis in general thoracic surgery wards, but the surgical approach may vary between single institutions. The videoassisted thoracoscopic surgery (VATS) approach is nowadays considered the gold standard, allowing a better aesthetic result and a more painless postoperative course [2], but intraoperative management of blebs/bullae and pleurodesis are reported in a heterogeneous way. Our institution has recently reported its experience [3] in pneumothorax surgical treatment with an innovative minimally invasive tool which uses radiofrequency

energy to make bullae collapse and preserve the integrity of the visceral pleura. This surgical instrument is very thin and flexible bringing two main advanges: firstly, it requires smaller incision than stapler devices, secondly it can easily reach all the parts of chest cavity. Moreover, the same tool might be used also to perform pleurodesis through electrocoagulation of intercostals arches. In our experience, we achieved a very low postoperative complication rate (1.4%) and recurrence rate (2.7%). A greater attention to improve minimally invasive surgery and a less traumatic approach towards lung parenchyma are key for the future development of pneumothorax surgical treatment. Although wider cohorts are needed to validate our good results, the use of new technologies may not only decrease recurrences rate and invasiveness but also dramatically reduce postoperative air leak, length of hospital stay and, as a consequence, costs for the health care system. Conflict of interest: none declared. References [1] Imperatori A, Rotolo N, Spagnoletti M, Festi L, Berizzi F, Di Natale D et al. Risk factors for postoperative recurrence of spontaneous pneumothorax treated by video-assisted thoracoscopic surgery Interact CardioVasc Thorac Surg 2015;20:647–653. [2] Baumann MH, Strange C, Heffner JE, Light R, Kirby TJ, Klein J et al. Management of spontaneous pneumothorax. An American College of Chest Physicians Delphi Consensus Statement. Chest 2001;119:590–602. [3] Ambrogi MC, Zirafa CC, Davini F, Giarratana S, Lucchi M, Fanucchi O et al. Transcollation® technique in the thoracoscopic treatment of primary spontaneous pneumothorax. Interact CardioVasc Thorac Surg 2015;20: 445–448.

eComment. A bicycle inner tube in a glass of water! Video-assisted thoracoscopic surgery for spontaneous pneumothorax and the submersion test Authors: Paolo Scanagatta, Stefano Sestini, Leonardo Duranti and Federico Piccioni Division of Thorac Surg and Department of Anesthesia, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy doi: 10.1093/icvts/ivv052 © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved. We read with interest the well-written study by Imperatori et al. about risk factors for postoperative recurrence of spontaneous pneumothorax (SP) treated by videoassisted thoracoscopic surgery (VATS) [1]. Not surprisingly, the authors found a correlation between postoperative prolonged air leaks and recurrence of SP, which they attributed to the overlooking of leaking bullae, given that air leakage tests are sometimes difficult to interpret during VATS. We would like to comment on this. According to Naunheim and colleagues, the only independent predictive factor for the recurrence of SP is the failure to identify and resect blebs during surgery [2]. The key point is that the working space of VATS is very narrow, requiring the lung parenchyma to be held in an unnatural state to perform the submersion test correctly, and the evaluation of air leaks could be more effective when the lung is examined under a normal physiological state, i.e. fully inflated and without any mechanical pressure applied by the surgeon [3]. In fact, submersion test is similar to that when one is trying to find a hole in the inner tube of a bicycle wheel and performing this test on a lung during VATS is quite akin to submerging an inner tube in a glass of water. Therefore, after having performed a negative submersion test, we suggest checking air leaks using mechanical ventilator measurements before ending the surgical procedure. The ventilator test procedure could be as follow: 1) the ventilator setting is placed to volume-controlled modality, with two lung ventilation and at a fixed predefined tidal volume; 2) the evaluation is performed after having waited for the operated lung to re-inflate completely; 3) if there is an air-leakage >5% measured by the inhaled/exhaled tidal volume ratio, the submersion test must be repeated and the visceral pleural surface accurately re-checked to identify blebs or discontinuation of surgical suture-lines; 4) at the same time, it is easy to detect the presence of air leak looking at volume curve or at the pressure-volume loop. With a significant leak, the volume curve does not return to zero at the end of expiration but instead resets at the start of the next ventilator breath [4]. Similarly, the expiratory portion of the pressure-volume loop does not return to baseline in presence of a leak.

Risk factors for postoperative recurrence of spontaneous pneumothorax treated by video-assisted thoracoscopic surgery†.

Over the past two decades, video-assisted thoracoscopic blebectomy and pleurodesis have been used as a safe and reliable option for treatment of spont...
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