Larger polyglycolic acid sheet pleural covering to reduce postoperative recurrence of primary spontaneous pneumothorax

Abstract

Background

Post-bullectomy pleural-covering procedures using reinforcement materials, particularly polyglycolic acid (PGA) sheets, are routinely performed to prevent postoperative recurrence of pneumothorax (PORP). However, the optimal size of PGA sheets remains unknown, causing variability in surgical practice. We evaluated the prognostic significance of larger PGA sheets for reducing PORP rates.

Methods

This single-center retrospective study included patients who underwent thoracoscopic bullectomy for primary spontaneous pneumothorax (PSP) between March 2006 and March 2020. Participants were stratified according to the size of the PGA sheets used for pleural covering (large, 225 cm² and small, 100 cm²). Using Cox proportional hazards regression and inverse probability of treatment weighting (IPTW), the intergroup difference in PORP rates was analyzed to determine the impact of PGA sheet size on postoperative outcomes.

Results

In the study cohort with 185 participants, 152 and 33 were assigned to the large and small groups, respectively. PORP incidence was significantly lower in the large group (3.9%, 6/152) than in the small group (12.1%, 4/33), and IPTW-adjusted multivariable Cox regression analysis indicated a significantly reduced recurrence rate in the large group than in the small group (hazard ratio, 0.11, P<0.01).

Conclusions

Using larger PGA sheets to cover the staple line during bullectomy for PSP significantly reduces the postoperative recurrence rate. Adequately sized PGA sheets should be used to provide sufficient coverage beyond the staple line to optimize patient outcomes.

Highlight box.

Key findings

• This study investigates the effectiveness of thoracoscopic bullectomy with reinforcement using larger polyglycolic acid (PGA) sheets in patients with primary spontaneous pneumothorax (PSP). The key findings show that using larger PGA sheets significantly reduces the rate of postoperative recurrence, particularly in patients with multiple ipsilateral bullae or other high-risk factors, such as young age, low body mass index, smoking history, and underlying lung disease. Moreover, the study provides evidence that reinforcement enhances long-term outcomes, minimizing complications such as prolonged air leaks and reducing recurrence rates.

What is known and what is new?

• Bullectomy is a well-established surgical treatment for PSP, but postoperative recurrence remains an issue, especially in cases with multiple or large bullae. Various reinforcement materials have been examined, yet their effectiveness remains variable.

• This study demonstrates that using larger PGA sheets for staple-line reinforcement in thoracoscopic bullectomy can significantly reduce recurrence rates, especially in high-risk patients. The findings offer new evidence supporting the routine use of larger reinforcement sheets in clinical practice.

What is the implication, and what should change now?

• The results suggest that reinforcement with larger PGA sheets may be a more effective strategy to prevent recurrence in PSP patients, particularly those with multiple or high-risk bullae. Surgical protocols may benefit from revision to include this approach. Further prospective studies are warranted to validate long-term benefits on recurrence and lung function.

Introduction

Primary spontaneous pneumothorax (PSP), characterized by the rupture of pulmonary blebs and bullae, predominantly affects young males without pre-existing pulmonary disease. Conservative treatment, albeit effective, frequently results in PSP recurrence. Although surgical intervention, particularly thoracoscopic bullectomy, significantly aids recurrent pneumothorax management, it presents challenges, including a higher risk of postoperative recurrence of pneumothorax (PORP), compared with traditional thoracotomy with lung suturing, owing to the use of endoscopic linear staplers in thoracoscopic bullectomy (1). The transition from traditional to endoscopic surgery has introduced complications, such as staple-associated air leaks, overlooked bullae during thoracoscopic procedures, and the potential formation of new bullae. Mechanisms contributing to staple-associated air leaks include a check-valve effect caused by improper stapling that ignores the bronchial anatomy, overstretching of the visceral pleura owing to stapling and subsequent reinflation of the bullectomy site, and automatic linear stapler-induced localized lung damage (2,3).

To mitigate PORP risk, several adjunctive procedures have been developed, including pleural abrasion, pleural covering, pleurodesis, and reinforcement material use. The Japanese Association for Thoracic Surgery (JATS) report indicated that adjunctive procedures were performed in 69.9% (7,217 of 10,329) of bullectomies for PSP, of which 98.0% involved artificial material reinforcement (4). Notably, parietal pleurectomy was performed in only 1.4% of cases. Invasive procedures, such as pleural abrasion and covering, demonstrate good prognoses, with 2-year non-recurrence rates of 0–5% (5,6); nonetheless, they can present serious complications and impose adhesion-related challenges to reoperation. Conversely, reinforcement material use, particularly polyglycolic acid (PGA) sheets, is a simpler, noninvasive approach, with minimal complications. PGA sheets demonstrated significantly greater adhesion and inflammation (7); therefore, a correlation between reinforcement materials and reduced PORP rates has been suggested (8). However, few studies have evaluated long-term (>3 years) outcomes of bullectomy. Moreover, the optimal size of reinforcement materials remains undefined, often relying on individual surgeons’ discretion. This lack of consensus may induce variability in surgical outcomes, including an increased recurrence risk due to insufficient pleural coverage or potential complications associated with oversized materials.

This study aimed to evaluate the long-term outcomes and prognostic value of pleural covering procedures using larger PGA sheets. The primary objective was to determine whether the PGA sheet size used during thoracoscopic bullectomy impacts the PORP risk. The secondary objective was to investigate whether PGA sheet size influences other clinical outcomes, such as postoperative air leak (PAL), operative time, and recurrence patterns. We present this article in accordance with the STROBE reporting checklist (available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-24/rc).

Methods

Participants

Surgical indications for PSP included recurrent pneumothorax, hemopneumothorax, continuous air leaks post-thoracic drainage, bilateral pneumothorax, and certain social or occupational hazards (e.g., pilots), which may increase the risk of complications from recurrent pneumothorax. Between March 2006 and March 2020, 239 consecutive patients aged <40 years with PSP underwent thoracoscopic bullectomy at our Kobe Red Cross Hospital, a tertiary medical center. Exclusion criteria were: bullectomy without PGA sheet or mechanical stapling, prior thoracic surgery, conversion to open thoracotomy, and <1 year follow-up. This study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. This study was approved by the Institutional Review Board of Kobe Red Cross Hospital (No. 248). As this was a retrospective study using anonymized clinical data, the requirement for individual informed consent was waived based on the opt-out method approved by the ethics committee. Information about the study was disclosed on the hospital website, and patients were given the opportunity to decline their participation. Follow-up data were obtained via outpatient visits and telephonic interviews.

Surgical approach

A three-port thoracoscopic approach was used for bullae or bleb resection with mechanical stapling (Endo-GIA or Tri-Staple; Medtronic, Minneapolis, MN, USA) without lung suturing. Equal height staples (Endo GIA^TM; Medtronic) were used between March 2006 and March 2015, whereas graduated height staples (Tri-Staple^TM; Medtronic) were used between April 2015 and March 2020 sequentially. An air-leak test was performed post-bullectomy; additional lung resection was performed if major air leaks were present. Minor or no air leaks were treated with PGA sheet (NEOVEIL sheet type, thickness 0.15 mm, area 225 or 100 cm²; Gunze, Kyoto, Japan) coverage on staple lines using fibrin glue (BOLHEAL^®, KM Biologics Co. Ltd., Kumamoto, Japan). Fibrin glue was used in all cases. PGA sheets were used to completely cover staples; for bullae on the upper lobe’s lateral or apex, only the staple line was covered. For other locations, the sheet was divided to separately cover both the staple line and the apex of the upper lobe for prophylactic purposes. During the procedure, PGA sheets and fibrin glue were applied to the staple line while the lung was deflated. Due to the potential for slight displacement of the sheet from the staple line as the lung expands postoperatively, fibrin glue was not applied to the entire sheet, but rather focused on the staple line. This technique was selected to avoid complications due to sheet displacement during lung expansion. Participants were stratified by the PGA sheet size: L-type (225 cm²) and S-type (100 cm²), based on release timing of the sheets and surgeon preference. Although rare, S-type sheets were used in some cases because of unintended staff errors. The selection of PGA sheet size was not influenced by the size or number of bullae. Sheets were applied according to the standard technique described above, without specific consideration of bulla characteristics.

Postoperative management and follow-up

Closed water-sealed chest drainage was maintained until chest tube removal, which occurred after confirming no air leaks on the first postoperative day. Chest radiography was performed post-removal, and discharge followed if no lung collapse was noted. Follow-up visits at 1 week, 1 month, and 3 months after discharge included clinical assessments and chest radiographs to detect PORP and complications. High-risk patients or those with prior recurrence had extended follow-up.

Patients were prescribed analgesics until pain resolved and instructed to avoid strenuous activities, quit smoking, and perform deep breathing exercises. Patients were also instructed to observe complication signs like chest pain or breathing difficulty and to seek immediate medical attention accordingly. Adherence to activity restrictions and smoking cessation was evaluated during follow-up outpatient visits.

PORP was defined as post-discharge pneumothorax recurrence, excluding recurrences during the initial hospital stay. Recurrence was classified as any new pneumothorax detected through imaging, regardless of symptoms, and included both symptomatic patients who presented to the hospital and asymptomatic patients diagnosed incidentally.

Statistical analysis

All statistical analyses were conducted using RStudio (RStudio Team, 2023) within R (version 4.2.1, R Core Team, 2022). Categorical data are presented as frequency (proportion) and analyzed using the Chi-squared test; continuous data are presented as median [interquartile range] and analyzed using the Mann-Whitney U test. A Cox proportional hazards model accounted for confounding factors such as follow-up duration. Univariable and multivariable unweighted Cox regression analyses were used to evaluate non-PORP intervals. Continuous variables were categorized based on their median values observed in the study cohort. Specifically, age was categorized as <21 vs. ≥21 years, body mass index (BMI) as <19.1 vs. ≥19.1 kg/m², and the number of staples as <3 vs. ≥3. These thresholds reflect the median values observed in our dataset. The univariable analysis included the following variables: L-type vs. S-type, age (≥21 vs. <21 years), pneumothorax side (right vs. left), smoking history (SH; present vs. absent), BMI (≥19.1 vs. <19.1 kg/m²), number of staples (≥3 vs. <3), staple type (graduated vs. equal height), air-leak test results, and PAL >3 days. Variables with P≤0.25 were included in the multivariable analysis, which simultaneously assessed all nine factors. The P≤0.25 threshold was based on prior literature (9). Cases with missing data were excluded from the analysis to ensure consistency. Statistical significance was set at P<0.05. The recurrence-free interval (RFI) was defined as the time from surgery to the last follow-up, recurrence diagnosis, or death. Kaplan-Meier curves estimated RFI, and log-rank tests compared L-type and S-type groups. Among the nine variables analyzed using Cox regression, seven variables, excluding the intervention variable (PGA sheet size) and PAL for >3 days (which may be influenced by intervention factors), underwent stabilized inverse probability of treatment weighting (IPTW) adjustment. Subsequently, truncation was applied at the 1–99% percentiles. For the seven factors adjusted for stabilized IPTW and truncation, PGA sheet size and PAL for >3 days were added, and weighted Cox regression analysis was performed for both univariable and multivariable analyses. The selection criteria for variables in the multivariable analysis were the same as those used in the unweighted Cox regression analysis.

Results

Between March 2006 and March 2020, 403 patients with pneumothorax underwent thoracoscopic bullectomies at Kobe Red Cross Hospital. Patients were excluded based on: age ≥40 years (n=164), lack of use of PGA sheets as a covering procedure (n=28), history of prior intrathoracic surgery (n=18), conversion to open thoracotomy (n=4), postoperative follow-up of <1 year (n=3), and cases where staplers were not used during bullectomy (n=1). The final analysis included a retrospective review of 185 patients aged <40 years who underwent their first thoracoscopic bullectomy using both staplers and PGA sheets (Figure 1). The clinical characteristics of the patients in the L-type (n=152) and S-type (n=33) groups are summarized in Table 1. No statistically significant intergroup differences were found in the median age or BMI, sex, pneumothorax side, SH, or preoperative hemothorax.

Figure 1.

Flowchart of patient enrolment. PGA, polyglycolic acid.

Table 1. Clinical characteristics of patients who underwent thoracoscopic bullectomy classified by PGA sheet size.

Variable	Total (n=185)	L-type (PGA sheet 225 cm2) (n=152)	S-type (PGA sheet 100 cm2) (n=33)	P value
Age (years)	21 [18–26]	21 [18–26]	20 [17–23]	0.11
Sex				>0.99
Male	168 (90.8)	138 (90.8)	30 (90.9)
Female	17 (9.2)	14 (9.2)	3 (9.1)
Pneumothorax side				0.20
Right	83 (44.9)	72 (47.4)	11 (33.3)
Left	102 (55.1)	80 (52.6)	22 (66.7)
Smoking history				0.75
Yes	46 (24.9)	39 (25.7)	7 (21.2)
No	139 (75.1)	113 (74.3)	26 (78.8)
BMI (kg/m2)	19.1 [17.7–20.4]	19.1 [17.7–20.4]	18.8 [17.7–19.8]	0.58
Preoperative hemothorax	7 (3.8)	4 (2.6)	3 (9.1)	0.21

Categorical data are presented as number (%). Continuous data are presented as median [interquartile ranges]. BMI, body mass index; PGA, polyglycolic acid.

The pneumothorax was right-sided in 47.4% of L-type and 33.3% of S-type cases, with no significant intergroup difference. The operation time was comparable between groups (P=0.29). Perioperative data are summarized in Table 2.

Table 2. Perioperative data.

Variables	Total	L-type (PGA sheet 225 cm2)	S-type (PGA sheet 100 cm2)	P value
Operation time (min)	45 [38–55]	45 [38–55.2]	43 [35–55]	0.29
Bulla location
Apex	170 (91.9)	138 (90.8)	32 (97.0)	0.41
Superior segment	12 (6.5)	11 (7.2)	1 (3.0)	0.62
Others	17 (9.2)	15 (9.9)	2 (6.1)	0.72
Number of staples	2 [2–3]	2 [2–2.25]	2 [2–3]	0.46
Linear endoscopic stapler				0.41
Equal height staples	103 (55.7)	82 (53.9)	21 (63.6)
Graduated height staples	82 (44.3)	70 (46.1)	12 (36.4)
Air leak in air leak test	15 (8.1)	11 (7.2)	4 (12.1)	0.56
Postoperative prolonged air leak (≥3 days)	9 (4.9)	8 (5.3)	1 (3.0)	0.93
Follow-up period (months)	59.0 [27.2–85.9]	59.3 [29.4–84.5]	43.9 [21.9–93.2]	0.34
Postoperative recurrence of pneumothorax	10 (5.4)	6 (3.9)	4 (12.1)	0.15

Categorical data are presented as number (%). Continuous data are presented as median [interquartile ranges]. PGA, polyglycolic acid.

Regarding the bulla location, the apex was involved in 91.9% of cases, the edge of the superior segment in 6.5%, and other locations in 9.2% (lateral upper lobe, n=9, lung base, n=3, middle lobe, n=2, lingula, n=2, and interlobar surface, n=1). No significant intergroup differences were detected in bulla location [apex: 90.8% vs. 97.0% (P=0.41), the superior segment: 7.2% vs. 3.0% (P=0.62), and other locations: 9.9% vs. 6.1% (P=0.72)]. Similarly, no significant intergroup difference was observed when two staples were used (P=0.46).

In the L-type and S-type groups, respectively, regarding linear endoscopic staplers, the proportion of equal-height staples was 53.9% and 63.6% (P=0.41); the rates of minor air leaks after bullectomy were 7.2% and 12.1% (P=0.56); and the PAL rates were 5.3% and 3.0% (P=0.93). The median follow-up period was 59.0 (27.2–85.9) months; 59.3 (29.4–84.5) months in the L-type group and 43.9 (21.9–93.2) months in the S-type group (P=0.34). The PORP rate was 5.4% overall, and 3.9% and 12.1% in the L-type and S-type groups, respectively (P=0.15).

Owing to the varied follow-up periods, Cox proportional hazards regression was performed, including both univariable and multivariable analyses (Table 3). Multivariable analysis revealed that the L-type PGA sheet was a predictor of reduced PORP [hazard ratio (HR), 0.19; 95% confidence interval (CI): 0.04–0.72; P=0.02], while right-sided pneumothorax (HR, 4.47; 95% CI: 1.03–19.43; P=0.05) and PAL lasting >3 days (HR, 6.33; 95% CI: 1.19–33.52; P=0.03) were predictors of increased PORP. Minor air leaks after bullectomy (HR, 3.73; 95% CI: 0.73–19.10; P=0.11) tended to increase the risk of recurrence. The model’s predictive accuracy was good (C-index =0.78; 95% CI: 0.64–0.93). Given the small sample size of the S-type group, a stabilized IPTW was performed to adjust for confounding factors in the observational data. Table 4 shows the changes in the seven variables before and after IPTW adjustment and truncation. After adjustment, all standardized mean differences (SMD) for the variables were less than 0.1. Table 5 presents the results of the weighted Cox regression analysis after stabilizing IPTW and truncation. The multivariable analysis revealed that the L-type PGA sheet was a predictor of reduced PORP (HR, 0.11; 95% CI: 0.03–0.50; P=0.004). Right-sided pneumothorax (HR, 5.37; 95% CI: 0.61–47.41; P=0.13), the use of more than three staples (HR, 0.58; 95% CI: 0.09–3.68; P=0.56), and the use of graduated height staples (HR, 2.62; 95% CI: 0.55–12.47; P=0.23) were also assessed, but no significant differences were found. The model’s predictive accuracy was good (C-index =0.82; 95% CI: 0.67–0.97).

Table 3. Unweighted Cox regression analysis to evaluate non-PORP interval.

Variables	Univariable analysis					Multivariable analysis
	Coef	HR	95% CI	P value		Coef	HR	95% CI	P value
PGA sheet size (L-type vs. S-type)	−1.20	0.30	0.09–1.07	0.06		−1.65	0.19	0.04–0.72	0.02
Age (≥21 vs. <21 years)†	0.32	1.37	0.39–4.87	0.62		–	–	–	–
Pneumothorax side (right vs. left)	1.11	3.03	0.78–11.74	0.11		1.50	4.47	1.03–19.43	0.05
SH (present vs. absent)	0.78	2.19	0.62–7.76	0.23		0.70	2.02	0.53–7.74	0.30
BMI (≥19.1 vs. <19.1 kg/m2)†	0.38	1.46	0.41–5.16	0.56		–	–	–	–
Number of staples (≥3 vs. <3)†	0.24	1.28	0.33–4.94	0.72		–	–	–	–
Staples (graduated height vs. equal height)	0.42	1.52	0.44–5.30	0.51		–	–	–	–
Air leak test (air leak vs. non-air leak)	1.01	2.74	0.58–12.91	0.20		1.32	3.73	0.73–19.10	0.11
Postoperative air leak (≥3 vs. <3 days)	1.84	6.29	1.33–29.78	0.02		1.84	6.33	1.19–33.52	0.03

^†, continuous data were dichotomized into two categories based on the median values, converting them into categorical data. BMI, body mass index; CI, confidence interval; Coef, coefficient; HR, hazard ratio; PGA, polyglycolic acid; PORP, postoperative recurrence of pneumothorax; SH, smoking history.

Table 4. Variables for characteristics and perioperative data before and after stabilized IPTW adjustment.

Variables	Before stabilized IPTW adjustment					After stabilized IPTW adjustment
	L-type, n (%)	S-type, n (%)	SMD	P value		L-type, weighted mean (%)	S-type, weighted mean (%)	SMD	P value
Age (≥21 years)†	81 (53.3)	14 (42.4)	0.22	0.62		51.0	52.9	0.04	0.71
Pneumothorax side (right)	72 (47.4)	11 (33.3)	0.29	0.11		44.5	47.2	0.05	0.70
SH	39 (25.7)	7 (21.2)	0.10	0.23		25.2	28.7	0.08	0.83
BMI (≥19.1 kg/m2)†	77 (50.7)	16 (48.5)	0.04	0.56		49.8	52.5	0.05	0.58
Number of staples (≥3)†	38 (25)	9 (27.3)	0.05	0.72		25.5	22.8	0.06	0.66
Staples (graduated height)	70 (46.1)	12 (36.4)	0.20	0.51		43.8	42.2	0.03	0.85
Air leak test (air leak)	11 (7.2)	4 (12.1)	0.16	0.20		8.0	6.6	0.05	0.72

^†, continuous data were dichotomized into two categories based on the median values, converting them into categorical data. BMI, body mass index; IPTW, inverse probability of treatment weighting; SH, smoking history; SMD, standardized mean difference.

Table 5. Stabilized IPTW-adjusted Cox regression analysis to evaluate non-PORP interval.

Variables	Univariable analysis					Multivariable analysis
	Coef	HR	95% CI	P value		Coef	HR	95% CI	P value
PGA sheet size (large-type vs. small-type)	−1.48	0.23	0.06–0.82	0.02		−2.18	0.11	0.03–0.50	0.004
Age (≥21 vs. <21 years)†	0.16	1.18	0.23–5.98	0.84		–	–	–	–
Pneumothorax side (right vs. left)	1.40	4.05	0.76–21.64	0.10		1.68	5.37	0.61–47.41	0.13
SH (present vs. absent)	0.90	2.46	0.48–12.57	0.28		–	–	–	–
BMI (≥19.1 vs. <19.1 kg/m2)†	−0.23	0.79	0.15–4.19	0.78		–	–	–	–
Number of staples (≥3 vs. <3)†	−1.09	0.34	0.08–1.49	0.15		−0.55	0.58	0.09–3.68	0.56
Staples (graduated height vs. equal height)	0.97	2.63	0.64–10.79	0.18		0.96	2.62	0.55–12.47	0.23
Air leak test (air leak vs. non-air leak)	−0.06	0.94	0.18–5.05	0.95		–	–	–	–
Postoperative air leak (≥3 vs. <3 days)	0.79	2.21	0.35–14.11	0.40		–	–	–	–

^†, continuous data were dichotomized into two categories based on the median values, converting them into categorical data. BMI, body mass index; CI, confidence interval; Coef, coefficient; HR, hazard ratio; IPTW, inverse probability of treatment weighting; PGA, polyglycolic acid; PORP, postoperative recurrence of pneumothorax; SH, smoking history.

The Kaplan-Meier curves for RFIs indicated a significant difference between the L-type and S-type groups (P=0.050) (Figure 2). The 1-year PORP rates were 2.0% and 3.0% for the L-type and S-type, respectively, whereas the 3-year PORP rates were 4.3% and 10.6%, respectively, with a notable between-group difference.

Figure 2.

Kaplan-Meier curve depicting the RFI for large-type (red line) and small-type (green line). The shaded areas represent the 95% confidence intervals. PGA, polyglycolic acid; RFI, recurrence-free interval.

Regarding PORP patterns, 2 of the 6 recurrence cases in the L-type group underwent reoperation, with recurrence from locations unrelated to the initial stapling line (the edge of the superior segment and interlobar surface). All reoperated cases in the L-type group showed adhesions at the apex of the lung covered by the PGA sheet; however, new bullae formed in areas separate from the original stapling line, leading to recurrence. In the S-type group, 2 of the 4 recurrence cases underwent reoperation. Both cases showed bulla neogenesis at the initial stapling line. Adhesions at the apex covered by the PGA sheet were also observed in all reoperated cases; however, newly formed bullae outside the adhesion areas caused recurrence. Of the 10 recurrence cases, 40.0% recurred within 1 year and 90.0% within 3 years.

Discussion

This retrospective study highlighted the significance of reinforcement with larger PGA sheets and evaluated the long-term outcomes of thoracoscopic bullectomy for PSP. Our findings underscore the complexity of PORP management, the role of PGA sheets in reducing air leaks, and the importance of optimizing surgical techniques.

The observed PORP rates in this study were consistent with the existing literature on thoracoscopic bullectomy (10-14). Although these rates are relatively low, the higher recurrence tendency with smaller PGA sheets suggests that larger sheets may better cover the stapling lines and thereby minimize the risk of air leaks. As confirmed herein, undersized PGA sheets are particularly prone to poor coverage owing to mechanical stapling, which can create small, inadequately sealed, concave spaces. The multivariable analysis identified PAL as a significant predictor of recurrence. However, in the stabilized IPTW-adjusted Cox regression analysis, the results indicated that the L-type group had a significantly lower recurrence rate compared to the S-type group, even when adjusted for surgical side. This suggests that larger PGA sheets may provide superior coverage and reduce the risk of recurrence, even in the presence of PAL.

Interestingly, when performing an unweighted Cox regression analysis, a significant difference in recurrence rates was observed between the left and right sides, with the recurrence being more common on the right side. However, when adjusting for confounding factors using IPTW-adjusted Cox regression, this significant difference was no longer observed. This highlights the potential impact of other factors, such as PGA sheet size and intraoperative technique, in mitigating recurrence regardless of the surgical side.

PAL may be associated with insufficient coverage of the staple line by PGA sheets and potential intraoperative oversights, such as missed bullae. Incomplete coverage occurred when the PGA sheets failed to fully cover the stapled area, particularly with smaller sheets. The mechanical action of the staples can create microgaps that, if not sufficiently sealed by the PGA sheet, may induce air leaks. Additionally, missed bullae during surgery—a known risk factor for thoracoscopic procedures—can contribute to PAL. Both these factors suggest the presence of leak points in the absence of postoperative coverage. However, the IPTW-adjusted Cox regression results indicated that PAL was not significantly associated with PORP, suggesting that while PAL may be related to intraoperative oversights, it does not have a direct impact on recurrence when adjusted for other factors.

The mechanisms underlying staple-associated air leaks, including the check-valve effect, overstretching of the visceral pleura, and local lung damage, underscore the need for careful surgical intervention. These challenges can be addressed more effectively by using larger PGA sheets with sufficient margins. In the current study, bulla neogenesis occurred in two S-type cases, with new bullae forming along the staple lines outside the adhesion zones, resulting in air leaks. This further highlights the importance of appropriate PGA sheet sizing and coverage. Furthermore, the addition of fibrin glue, by potentially sealing small defects that may contribute to complications, may provide an enhanced barrier against air leaks.

Many reports have indicated that PORP typically occurs within 1 year postoperatively (15,16); however, the majority of these reports had insufficient observation periods. Our long-term follow-up demonstrated that 40.0% of the recurrences occurred within 1 year, whereas 90.0% occurred within 3 years. Therefore, we recommend that future studies include a follow-up period of at least 3 years to more accurately assess the long-term outcomes and recurrence rates of thoracoscopic bullectomy for PSP (17).

Various additional procedures, such as pleural abrasion, pleurodesis, and reinforcement with artificial materials, have been used to prevent PORP. Although invasive methods, including pleural abrasion, have shown promising short-term outcomes with low recurrence rates, they confer risks of serious complications and difficult reoperations due to adhesions (5,6,18). In contrast, our use of a noninvasive reinforcement material, PGA sheets, resulted in minimal complications, making it the preferred material for PSP management. Although the use of PGA sheets does not cause adhesions to the chest wall to the same extent as pleural abrasion or covering, it still poses the risk of adhesions that may lead to complications during reoperation. This presents a significant challenge in the management of postoperative complications. Data from Japan have shown that 69.9% of patients undergoing bullectomy undergo additional procedures, with 98% involving artificial material reinforcement; this highlights the growing trend toward the use of less invasive methods. However, parietal pleurectomy was performed in only 1.4% of cases, which leaves room for further exploration of this technique for managing recurrent air leaks (3).

For patients with a lower body surface area, the larger PGA sheet may be too large, potentially causing inadequate lung expansion owing to excessive coverage. The use of larger PGA sheets should be carefully considered in smaller patients. Poor lung expansion was observed in almost all patients with larger PGA sheets at the 7-day follow-up after discharge, likely due to coverage over the apex. However, at the 1-month follow-up, full lung expansion was achieved in almost all patients, except for those with PORP, indicating that the initial poor expansion was temporary and related to the mechanical impact of the PGA sheet. These findings suggest that, although larger PGA sheets may initially hinder lung expansion, their long-term benefit in preventing recurrence outweighs this short-term issue.

Splitting larger PGA sheets for use is recommended in cases with multiple bullae located in different areas. However, adding smaller PGA sheets or combining them with oxidized regenerated cellulose (ORC) sheets may also be reasonable. As a practical approach, splitting the larger PGA sheet for the upper lung and using smaller PGA sheets for the superior segments of the lower lobe should be considered. Alternatively, the ORC sheet can be combined with a PGA sheet to enhance fixation and reinforce affected areas. The combination of these methods can optimize both therapeutic outcomes and cost efficiency. However, splitting larger PGA sheets is more cost-effective than adding smaller PGA or ORC sheets.

This study had some limitations. First, its retrospective nature holds inherent biases, potentially leading to inaccurate estimation of certain risk factors due to incomplete or inconsistent data collection. Second, its single-center design limits the generalizability of the findings, as the study population may not fully reflect the diversity seen in broader clinical settings. A more diverse patient cohort might provide more robust and externally valid conclusions. Third, variability in the use of PGA sheet types due to differences in their release date might have confounded the results and altered the observed effects. Additionally, selection bias may have arisen because patients were selected from a limited institutional population, potentially excluding those with different clinical characteristics or treatment outcomes. Furthermore, factors such as the surgeons’ preference and experience, surgical technique, inter-operator variability, differences in anesthesia, and the use of other relevant equipment, such as sutures, may have influenced the outcomes, emphasizing the need for standardized protocols. Future multicenter prospective cohort studies with consistent surgical techniques, anesthesia protocols, and follow-up assessments are essential to validate these findings. These studies should also include a larger, more diverse patient population to enhance the generalizability of the results while minimizing variability across centers by ensuring uniformity in surgeon experience and operative protocols.

Conclusions

Our study reinforces the importance of using larger PGA sheets for thoracoscopic bullectomy of PSP. The identification of prolonged air leaks as a predictive factor for recurrence highlights the need for vigilant postoperative management. When air leaks persist for >3 days, adhesion therapy may further improve outcomes. Although the use of larger PGA sheets may be more technically demanding than the use of smaller sheets, their ability to reduce PORP with few complications makes them a superior option. The potential benefits of using larger PGA sheets could have a substantial impact on PSP treatment outcomes, underscoring the importance of this study’s findings for clinicians and researchers. By addressing the challenges associated with PORP, surgical success can be enhanced and better care for patients with PSP can be provided.

Supplementary

The article’s supplementary files as

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. This study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. This study was approved by the Institutional Review Board of Kobe Red Cross Hospital (No. 248). Informed consent for this retrospective analysis was waived.

Data Sharing Statement

Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-24/dss

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DOI: 10.21037/jtd-2025-24