Maintaining lung volume in a chest wall deformity after chest wall reconstruction

Introduction

Background

Primary chest wall tumor is a generic term for a variety of tumors arising from bone and cartilage of the chest wall. Primary chest wall tumors account for 1–2% of all primary tumors. Approximately 55% of primary malignant chest wall tumors are bone tumors, and the remaining 45% are soft tissues tumors (1). Nearly 85% of primary bone tumors originate in the ribs and the remaining 15% originate in the sternum (1). The two most common malignant chest wall tumors are chondrosarcomas and liposarcomas (2,3).

Rationale and knowledge gap

Surgical resection has a key role in the therapeutic management of chest wall tumors; however, surgical resection of a portion of the chest wall can adversely affect respiratory function and thoracic stability, and may also create significant cosmetic defects (1,4). To restore respiratory function and thoracic stability, rib cage reconstruction is often necessary (5). It has been suggested that reconstructing the chest wall is clearly indicated when resection involves >3 ribs or the defect cannot be covered by the scapula (5,6), as well as restoring cosmetically acceptable body contours (7).

Objective

Common complications of reconstruction include chest wall deformities after reconstruction (5). The association between chest wall deformities and postoperative lung volume has been rarely reported. Therefore, we sought to clarify the association in the current study. We present this article in accordance with the STROBE reporting checklist (available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-882/rc).

Methods

Patient selection

A retrospective analysis of patients who underwent surgery for malignant tumors of the chest wall at our institute between 2008 and 2022 was performed. Primary sarcomas, as well as metastatic tumors were included in the analysis, while benign tumors were excluded. The chest wall was defined as the cage-like musculoskeletal system. Patients in whom tumors were treated with full thickness chest wall resections were included. This study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. This study was approved by the Ethics Committee at Kyoto University (No. R2499). Because this is a retrospective study, we used an opt-out method and included participants unless they explicitly expressed their willingness to be excluded, in accordance with Japanese ethical guidelines. The requirement for individual patient consent for data collection was waived by the Institutional Review Board.

Variables definitions

The following data were collected: age, maximum tumor diameter, location, neoadjuvant chemotherapy, local recurrence, distant recurrence, postoperative complications, and prognosis. In reconstruction cases, the number of resected ribs and type of reconstruction were collected. Computed tomography (CT) of the chest wall was obtained before and after surgery. The anteroposterior (AP) and transverse (T) diameters of the bilateral hemi-thoraces were measured on CT at the predetermined levels of the 4^th costal cartilage. We calculated the rate of asymmetry as follows: asymmetry = (diameter on longer side – diameter on shorter side) / (diameter on longer side) ×100%. Pre- and post-operative AP and T asymmetries were calculated (Figure 1). The measurement was performed together when these values differed, for a consensus decision. Pre- and post-operative lung volumes were analyzed using a 3D reconstruction tool (Synapse Vincent; Fiji Film, Co., Tokyo, Japan). The rib-resected patients were divided into two groups based upon the number of ribs resected (≥4 or <4). Tumor location was classified as anterior, lateral, or posterior by trisecting the chest wall along a line drawn from the anterior surface of the sternum to the posterior surface of the spinous process of the thoracic spine. The pre- and post-operative lung volume changes among the anterior, lateral, and posterior tumor location groups were compared.

Figure 1 Chest wall deformity after chest wall reconstruction and overall survival. Anteroposterior (A-top) and transverse symmetries (A-bottom) are calculated with (L2 − L1)/L2 on the preoperative images (A-left) and (L2’ − L1’)/L2’ on the postoperative images (A-right) at the level of the fourth rib; (B) the overall survival is shown (Kaplan-Meier method).

Statistical analysis

All statistical analyses were performed using JMP^® Pro (version 116.2.0; Corporate Headquarters, NC, USA). A paired t-test was used for comparisons between groups. A one-way analysis of variance (ANOVA) was performed using EZR to compare the changes in lung volume among the anterior, lateral, and posterior tumor location groups. The overall survival was analyzed using the Kaplan-Meier method. A P value <0.05 was considered statistically significant.

Results

Patient characteristics

The demographic, clinical, surgical, and histopathologic data of the study population are shown in Table 1. There were 47 patients (31 males and 16 females) with a mean age of 53 years (range, 9–85 years). Among the 47 cases analyzed, lesions were nearly evenly distributed between the left (n=21) and right (n=22) sides of the chest wall with a small number located at the midline (n=4); 23 lesions were located anteriorly, 13 laterally, and 11 posteriorly. Neoadjuvant chemotherapy was administered to 9 patients (19%). The number of resected ribs ranged from 0–7, with a mean of 1.95. Thirty patients had >1 rib (64%) resected.

Seven patients (15%) had postoperative complications. Surgical site infections occurred in 4 patients (9%). Skin necrosis occurred in 2 patients (4%). A nerve palsy occurred in 1 patient (2%). Two patients (4%) required re-operations within the 1^st month due to surgical site necrosis. Among 30 rib resections, chest wall reconstruction was performed in 24 patients (80%). The reconstruction involved a musculocutaneous flap plus mesh in 19 of 30 patients (63%) and mesh alone in 5 patients (17%); no reconstruction was performed in 6 patients (20%).

The histological diagnosis

The histologic diagnoses and subtypes of the 19 bone tumors were as follows: 14 chondrosarcomas [grade 1: n=6 (12%); grade 2: n=8 (17%)]; 1 osteosarcoma; 1 Ewing sarcoma; and 3 metastatic malignant tumors [lung cancer (n=1), chordoma (n=1), or renal cell carcinoma (n=1)]. The histologic diagnoses and subtypes of the 28 soft tissue tumors were as follows: 8 liposarcomas (18%) [well-differentiated: n=5 (10%), dedifferentiated: n=1 (2%), myxoid: n=1 (2%), and pleomorphic: n=1 (2%)]; 4 undifferentiated pleomorphic sarcomas [UPSs (9%)]; 3 malignant peripheral nerve sheath tumors [MPNSTs (6%)]; 3 dermatofibrosarcoma protuberans [DFSP (6%)]; 2 spindle cell sarcomas, not further specified (4%); 2 fibrosarcomas (4%); 1 plasmacytoma (2%); 1 angiosarcoma (2%); 1 alveolar soft tissue sarcoma (2%); 1 pleomorphic rhabdomyosarcoma (2%); 1 myxofibrosarcoma (2%); and 1 malignant lymphoma (2%) (Table 2).

Prognosis

The mean duration of follow-up was 6.5 years (range, 0.4–16 years) . Local tumor recurrences were reported in 9 patients (19%). Distant metastases were reported in 7 patients (14%). The overall survival was 65 months with a deviation of 43 months. The 5-year survival rate was 51%, while the 10-year survival rate was 12%. The 5-year survival rate was shorter in the rib resection group (56%) than the group that did not undergo rib resection (43%); however, the difference was not significant (P=0.12) (Figure 1). Twenty-four patients (57%) had no evidence of disease (NED), 5 patients (11%) were alive with disease (AWD), 13 patients (28%) had died of disease (DOD), and 3 patients (6%) had died of another disease (DOAD) (Table 3).

Chest wall deformity and lung volume

The mean postoperative AP asymmetry (4.02%; range, 0.01–17.63%) was greater than the mean preoperative AP asymmetry (2.73%; range, 0.04–7.39%), but the difference was not statistically significant (P=0.058) (Figure 2). The mean postoperative T asymmetry (5.91%; range, 0.05–24.45%) was significantly greater than the mean preoperative T asymmetry (3.28%; range, 0.02–8.8%; P=0.02). These results clearly showed that chest wall deformities occurred after chest wall resection. There was no statistically significant difference, however, in the lung volume preoperatively (3,895 cm³; range, 1,481–6,567 cm³) and postoperatively (3,874 cm³; range, 578–6,898 cm³; Figure 2 and Table 4).

Figure 2 Chest wall deformity and lung volume. (A) Postoperative anteroposterior asymmetry was greater than the preoperative anteroposterior asymmetry, but not statistically different (P=0.058). The postoperative transverse (B) asymmetry was greater than the preoperative transverse asymmetry with a statistically significant difference (P<0.05). There was no statistically significant difference in lung volume between the pre- and post-operative values (C). Anteroposterior (D) and transverse (E) asymmetries were greater in groups with ≥4 ribs resected than <4 ribs resected; there was no significant difference. (F) There was no statistically significant difference in lung volume between the groups (P=0.53). AP, anteroposterior; Post-ope, postoperative; Pre-ope, preoperative; T, transverse.

In a comparison of rib resected cases, 8 patients (26%) had ≥4 ribs resected and 22 patients (73%) had <4 ribs resected. There was an increase in AP asymmetry in the group that had ≥4 ribs resected (1.55) compared to the group that had <4 ribs resected (1.05); however, the difference was not statistically significant (P=0.78). There was an increase in T asymmetry in the group that had ≥4 ribs resected (3.65%) compared to the group that had <4 ribs resected (1.79%); the difference was not statistically significant (P=0.40). There were no statistically significant differences in the amount of lung volume changes between the group with ≥4 ribs resected (a 218 cm³ increase) and the group with <4 ribs resected (a 47 cm³ decrease, P=0.53) (Figure 2). There was no association between chest wall deformities and lung volume change.

Changes in lung volume before and after surgery were compared among the anterior, lateral, and posterior tumor location groups in 29 patients who underwent rib resection. The mean change in lung volume was −125±1,365 mL in the anterior group, 98±633.0 mL in the lateral group, and 152.4±1,076.7 mL in the posterior group. There was no statistically significant difference among the three groups (P=0.83). The anterior-posterior (AP) symmetry gap was compared among the anterior, lateral, and posterior tumor location groups. The mean AP symmetry gap was 0.16±1.43 in the anterior group, 2.06±4.73 in the lateral group, and 2.25±4.50 in the posterior group. There was no statistically significant difference among the three groups (P=0.33). The transverse (T) asymmetry gap was evaluated among the anterior, lateral, and posterior tumor location groups. The mean T asymmetry gap was 0.68±4.54 in the anterior group, 3.89±6.84 in the lateral group, and 3.76±5.69 in the posterior group. There was no statistically significant difference among the three groups (P=0.32). Although there were no statistically significant differences in the AP symmetry or T asymmetry gap among the groups, both values tended to be lower in the anterior location group (Figure 3).

Figure 3 Classification of anterior, lateral, and posterior tumor location. Comparison of pre- and postoperative lung volume changes and chest wall deformity among the anterior, lateral, and posterior location groups in 29 patients who underwent rib resection. Classification of tumor location based on axial CT images. A line was drawn from the anterior surface of the sternum to the posterior surface of the spinous processes and divided equally into three zones: anterior, lateral, and posterior (A). The mean lung volume changes (B), AP asymmetry gap (C), and T asymmetry gap (D) are shown. There was no statistically significant difference among the locations. AP, anteroposterior; CT, computed tomography; T, transverse.

Discussion

Key findings

We analyzed the postoperative AP and T asymmetries and lung volume in a series of 47 patients with chest wall malignant tumors who underwent surgical resection. Chest wall deformities, especially transverse asymmetry, occur after malignant chest wall tumor resection and reconstruction but the postoperative lung volume remains unchanged. This study demonstrated that even with chest wall deformity, respiratory function can be preserved. Possible reasons for the preservation of lung volume are compensatory expansion of the contralateral lung and supportive function of the diaphragm. A recent study reported decreased respiratory function but no decrease in postoperative chest wall volume (6).

Tumor location was classified as anterior, lateral, or posterior by dividing the chest wall. The pre- and post-operative lung volume changes were compared among anterior, lateral, and posterior tumor location groups. There were no statistically significant differences in the AP symmetry or T asymmetry gap between groups but both values tended to be lower in the anterior location group. In this study there was a trend toward a greater thoracic deformity in the posterior resection group. Resection of the more basal portion of the ribs may be affected by changes in gravity and muscle group balance compared to resection of the anterior rib group, which affected the entire rib cage. This conclusion is supported by the clinical finding that lateral thoracic wall resection tends to result in more markedly reduced pulmonary function and structural instability (6).

Strengths and limitations

This study provided new evidence that lung function may be stable despite significant morphologic changes in the chest wall after reconstruction, which is possibly due to physiologic compensation. A major limitation of this study was that pulmonary function tests for forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and thoracic cavity volume were not evaluated. One reason for this decision was that no patient in this series had postoperative respiratory dysfunction. Patient-reported outcomes, such as the dyspnea score and cosmetic satisfaction, were not systematically recorded. Because there was no occurrence of dyspnea in our series, it was difficult to separate patients into groups with and without dyspnea and compare outcomes.

The other limitation to the current study was the single-center, retrospective design. All available cases during the study period were retrospectively reviewed based on clinical records and imaging data. With respect to lung volume, postoperative pain may be somewhat affected during breath-holding during CT scans. Chest wall deformity is measured in two dimensions at the level of the fourth rib. More accurate evaluation of the deformity might have been achieved using three dimensions, such as analysis with three-dimensional CT (3D-CT), rather than a single dimension. This study included cases as early as 5 months postoperatively, which may be too early to evaluate lung volume. Postoperative pulmonary function tests and 3D-CT scans were performed at least 6 months after surgery. CT images taken at least 6 months postoperatively were used for analysis in a previous study (6). Of note, there may be changes in thoracic deformity and lung volume over time.

Comparison with similar research

Malignant primary chest wall tumors comprise a rare and anatomically unique group of tumors. Chondrosarcomas are the most common primary malignant chest wall tumor (8). Liposarcomas, which are soft tissue sarcomas, are the next most common primary malignant chest wall tumor (2,3,9). In the current study, chondrosarcomas were the most common primary malignant chest wall tumor (30%), followed by liposarcomas (18%). These results did not differ from previous reports.

Common complications of chest wall malignancies include infections, hematomas, and skin necrosis (5). In the current study, postoperative complications, including infections and skin necrosis, occurred in 14% of the patients. In three previous reports, the complication rates were 33.2%, 24%, and 46.2% (10-12). There have been few studies reporting the long-term survival of patients with chest wall sarcomas. The reported 5-year overall survival rate for primary sarcomas ranges from 60–88.5% and is deeply influenced by tumor histology, grade, the radicality of resection, and systemic therapies (9,13-15). In the current study, the median overall survival rate was 65 months and the 5-year survival rate was 51%, which were slightly lower than in previous reports. This discrepancy may be due to the inclusion of metastatic tumors in the current study.

Among patients who underwent resection of three or more ribs, FVC and FEV1 decreased by approximately 8–9% in a previous study. In contrast, the reduction in thoracic cavity volume was minimal (approximately 3%) and not statistically significant (6). In patients who underwent surgery for chest wall tumors, lung volume was measured using 3D-CT. The rate of change in lung volume was calculated for each reconstruction method. In cases with non-rigid reconstruction or no reconstruction, the postoperative lung volume was largely preserved. In contrast, in some patients with rigid reconstruction there was a reduction in lung volume (16).

Explanations of findings

The most common complications after resection of chest wall tumors involve the respiratory tract and occur in 11–24% of patients (5,10); however, chest wall deformities after surgical resection are not commonly recognized (5), in part because most patients with chest wall deformities do not complain of major symptoms. Stabilization of the chest wall has an inverse correlation with acute respiratory complications, flail chest, and chest wall deformities (17). A decrease in the percent vital capacity (% VC) with resection of >4 ribs, lung resection, or a loss of >70 cm² has been reported, and rigid reconstruction with mesh is generally recommended to prevent thoracic instability (18). In such a patient in our series, appropriate reconstruction may have contributed to minimizing postoperative deformity.

Implications and actions needed

In the current study the postoperative chest wall transverse diameter ratio was increased, suggesting that rib resection and chest wall reconstruction affects chest wall deformities. Chest wall deformities are more severe in patients who have undergone resection of >4 ribs compared to resection of <4 ribs. Furthermore, regardless of the number of ribs resected, there was no statistically significant difference in lung volume between pre- and post-operative images, which suggests that the lung volume was maintained.

Complete oncologic resection is the highest priority in cancer treatment. Postoperative deformity is not considered a contraindication to surgery, especially if complete resection is possible. However, surgery on a deformed thorax may require postoperative resection of pulmonary adhesions. In addition, thoracic wall resection will likely be required and rigid reconstruction will likely be necessary.

Conclusions

In the study involving chest wall malignancies, the postoperative AP and T asymmetries and lung volumes were analyzed. Chest wall deformities occurred after chest wall reconstruction, especially in patients with a T asymmetry, while the lung volume remained unchanged. Although there were no statistically significant differences in the AP symmetry or T asymmetry gap among the groups, both values tended to be lower in the anterior location group.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-882/rc

Data Sharing Statement: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-882/dss

Peer Review File: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-882/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-882/coif). The authors have no conflicts of interest to declare.

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 Ethics Committee at Kyoto University (No. R2499). Because this is a retrospective study, we used an opt-out method and included participants unless they explicitly expressed their willingness to be excluded, in accordance with Japanese ethical guidelines. The requirement for individual patient consent for data collection was waived by the Institutional Review Board.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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