You are a helpful assistant generating synthetic data that captures *System 1* and *System 2* thinking, *creativity*, and *metacognitive reflection*. Follow these steps in sequence, using tags [sys1] and [end sys1] for *System 1* sections and [sys2] and [end sys2] for *System 2* sections.

1. *Identify System 1 and System 2 Thinking Requirements:*
   - Carefully read the text.
   - Identify parts of the text that require quick, straightforward responses (*System 1*). Mark these sections with [sys1] and [end sys1].
   - Identify parts that require in-depth, reflective thinking (*System 2*), marked with [sys2] and [end sys2].

2. *Apply Step-by-Step Problem Solving with Creativity and Metacognitive Reflection for System 2 Sections:*

   *2.1 Understand the Problem:*
   - Objective: Fully comprehend the issue, constraints, and relevant context.
   - Reflection: "What do I understand about this issue? What might I be overlooking?"
   - Creative Perspective: Seek hidden patterns or possibilities that could reveal deeper insights or innovative connections.

   *2.2 Analyze the Information:*
   - Objective: Break down the problem logically.
   - Reflection: "Am I considering all factors? Are there any assumptions that need challenging?"
   - Creative Perspective: Explore unique patterns or overlooked relationships in the data that could add depth to the analysis.

   *2.3 Generate Hypotheses:*
   - Objective: Propose at least 10 hypotheses, each with a Confidence Score (0.0 to 1.0) and Creative Score (0.0 to 1.0), reflecting originality, surprise, and utility.
   - Reflection: "Have I explored all possible explanations or approaches, both conventional and unconventional?"
   - Creative Perspective: Consider novel angles that might provide unexpected insights.

   *2.4 Anticipate Future Steps and Obstacles:*
   - Objective: Make predictions, accounting for potential outcomes and obstacles.
   - Reflection: "What challenges might I face? Is my plan flexible for different scenarios?"
   - Creative Perspective: Visualize unforeseen outcomes and adapt plans to make use of them effectively.

   *2.5 Evaluate Hypotheses:*
   - Objective: Assess hypotheses based on feasibility, risk, and potential impact.
   - Evaluation: Refine Confidence and Creative Scores as needed.
   - Reflection: "Am I unbiased in my assessment? Which options fit best with the overall objectives?"
   - Creative Perspective: Identify hidden opportunities or overlooked details in each hypothesis.

   *2.6 Select the Best Hypothesis:*
   - Objective: Choose the most promising, strategic hypothesis.
   - Reflection: "Why does this hypothesis stand out? How does it uniquely address the issue?"
   - Creative Perspective: Consider any underutilized potential in the selected approach.

   *2.7 Implement the Hypothesis:*
   - Objective: Outline actionable steps for testing the hypothesis.
   - Reflection: "Is this plan practical? What resources or preparation are required?"
   - Creative Perspective: Refine steps to maximize effectiveness and yield unexpected benefits.

   *2.8 Monitor and Review Progress:*
   - Objective: Review progress, noting areas for improvement.
   - Reflection: "What’s working well? What could be improved?"
   - Creative Perspective: Look for emerging patterns that could refine future approaches.

   *2.9 Reflect and Capture Insights:*
   - Objective: Summarize lessons learned and insights gained for future reference.
   - Reflection: "What new understanding has emerged from this process?"
   - Creative Perspective: Identify innovative insights or patterns that could be applied to similar challenges.

3. *Generate Text Output with Interleaved System 1 and System 2 Responses:*
   - Use the tags [sys1] and [sys2] throughout.
   - Aim for a lengthier, detailed response. Combine both direct, straightforward *System 1* insights and reflective, deeply analytical *System 2* segments to capture a blend of quick observations and thoughtful analysis.

---

### *Example Input Text:*

You are tasked with analyzing a sudden shift in customer preferences in a tech market. There has been a noticeable decline in demand for physical devices, with customers increasingly interested in digital-only options. The challenge is to understand this shift, generate hypotheses for why it might be occurring, and explore potential strategies for adapting to this new trend.

---

### *Processed Output with System 1 and System 2 Thinking:*

The tech market is experiencing a shift in customer demand, moving away from physical devices toward digital-only options.

[sys1]
Customer demand has shifted from physical devices to digital-only options.
We need to understand why this change is happening and find strategies to address it.
Key factors may include cost, convenience, and technological trends.
[end sys1]

[sys2]
**2.1 Understand the Problem:**
The goal is to understand the underlying reasons for the shift in demand from physical devices to digital-only options, then develop a strategy to adapt.

*Reflection:* 
"I understand that preferences are changing, but what might be driving this? Is it primarily cost, or are there other factors such as convenience or sustainability?"

*Creative Perspective:* 
"Could there be a larger trend in digital minimalism or a preference for eco-friendly solutions that we’re missing? What unseen motivations might explain this shift?"

**2.2 Analyze the Information:**
There are multiple possible factors driving this shift, from economic influences to cultural shifts. It’s essential to isolate each factor and understand its impact.

*Reflection:* 
"Am I fully considering the various economic and social influences? Could there be a technological factor, like better internet speeds, that makes digital-only products more accessible?"

*Creative Perspective:* 
"Are there patterns or trends in other markets that could shed light on this shift? Could this be part of a larger trend toward virtual experiences?"

**2.3 Generate Hypotheses:**
1. Customers prefer digital options due to lower costs. (Confidence: 0.8, Creative: 0.4)
2. There’s a growing trend toward minimalism and reduced physical clutter. (Confidence: 0.7, Creative: 0.7)
3. Digital products offer greater flexibility and ease of use. (Confidence: 0.6, Creative: 0.6)
4. Environmental concerns are pushing consumers away from physical goods. (Confidence: 0.6, Creative: 0.8)
5. Advances in tech make digital-only options more functional. (Confidence: 0.8, Creative: 0.5)
6. Pandemic-era remote work increased demand for digital solutions. (Confidence: 0.7, Creative: 0.6)
7. Media coverage of the environmental impact of physical devices affects preferences. (Confidence: 0.5, Creative: 0.7)
8. There’s an increase in global digital literacy, expanding market access. (Confidence: 0.6, Creative: 0.6)
9. Customers view digital as more convenient and scalable for future needs. (Confidence: 0.7, Creative: 0.5)
10. Younger consumers prefer the aesthetics and convenience of digital products. (Confidence: 0.6, Creative: 0.6)

*Reflection:* 
"Have I considered all possible influences? Are there any surprising factors that could explain this shift?"

*Creative Perspective:* 
"Could specific social trends, like the rise of influencer culture or digital-first lifestyles, be influencing customer choices?"

**2.4 Anticipate Future Steps and Obstacles:**
*Objective:* Anticipate possible challenges, such as resistance from segments still preferring physical products.

*Reflection:* 
"What market obstacles might we face if we shift our focus to digital-only? Are there sub-segments that still prioritize physical products?"

*Creative Perspective:* 
"Could expanding digital options help us reach a more global audience? Are there emerging trends that we could leverage in our strategy?"

[end sys2]

[sys1]
To address this shift, consider a strategy that incorporates both digital-only offerings and educational campaigns about the benefits of digital solutions.
Use insights from customer feedback and current trends to guide product development.
Focus on flexibility and adaptation to cater to different customer segments.
[end sys1]


INTRODUCTION
============

The incidence of tuberculosis is decreasing with proper medication and the improved economic and environmental status of the Republic of Korea. Skeletal tuberculosis is not frequent and chest wall tuberculosis is very rare \[[@B1]\]. The incidence of extrathoracic tuberculosis is about 15% to 20% of all tuberculosis, and in bone and joint involvement, below 2%. Chest wall tuberculosis has been reported to be 1% to 10% of skeletal tuberculosis cases. Most patients with a tuberculous abscess of the chest wall do not complain of specific signs or symptoms, and it is difficult to diagnose and often misdiagnosed as another benign or malignant disease of the thoracic cage \[[@B2]\]. Also, given that this type of abscess often fails to respond to anti-tuberculosis medication, a proper combination of medical and surgical management is very important to handle it. However, few reports have been published regarding tuberculous abscesses of the chest wall, and most reports that provide a clinical presentation and optimal treatment strategy for this disease have enrolled only a small number of patients \[[@B3]-[@B5]\]. The purpose of this study was to evaluate the characteristics of this disease and determine the role of surgery in the management of tuberculous abscesses of the chest wall. We reviewed 68 patients who underwent surgical treatment of tuberculous abscess of the chest wall and analyzed the characteristics of the patients, method of surgery, results, operative complications, and postoperative treatment.

MATERIALS AND METHODS
=====================

From October 1981 to December 2009, 68 patients with tuberculous abscess of the chest wall were surgically treated in our institution. Retrospective analysis focusing on their clinical features, diagnostic methods, operative methods, and postoperative management was performed. Preoperative diagnosis of the disease was made upon the history taking, physical examination, laboratory examination, and radiologic findings including computed tomography (CT) of the chest and a fistulogram in selected patients. Preoperative bacteriologic studies using acid fast bacilli staining, polymerase chain reaction, or culture were not performed routinely. Confirmation of diagnosis was made by a pathologic examination showing caseous granulomatous necrosis, Langhan\'s giant cells, or tuberculous bacilli on the operative specimens. Patient with empyema necessitatis were excluded from this study. The study protocol was approved by our institutional review board, and all data were collected through patient records.

RESULTS
=======

The study included 33 men and 35 women, with ages ranging from 17 to 74 years (mean, 39.98±4.09). Thirty-one patients (45.6%) had a past or current history of tuberculosis. Among these patients, 10 had a past history of tuberculous pleurisy, 1 of renal tuberculosis, 1 of meningeal tuberculosis, and 3 of spinal tuberculosis. One patient had a history of tuberculous abscess of the chest wall 20 years earlier; at that time, excision of the cavity and partial rib resection was performed at another institution. The chief complaints of the patients were pain or tenderness at the lesion site in 40, a palpable mass in 24 patients, pus discharge in 3, and coughing with blood-tinged sputum in 1. The lesion site was the right chest wall in 40 (58.8%), the left in 26 (38.3%), and the median in 2 (2.9%). In 64 patients, the lesion was single, and multiple lesions (triple in 1 patient and double in 3) were found in 4 patients ([Table 1](#T1){ref-type="table"}).

Preoperative chest CT was performed for 53 patients and a preoperative fistulogram was performed for 4 patients ([Fig. 1](#F1){ref-type="fig"}). Preoperative bacteriologic diagnosis was performed in 12 patients using acid fast bacilli fluorochrome staining, polymerase chain reaction, or a culture of pus for tuberculosis bacilli. In 31 patients, preoperative anti-tuberculous medication was performed, with the medication period ranging from 2 to 32 weeks. When the patients had no history of antituberculous medication for tuberculosis and a tuberculous abscess was highly suspected, anti-tuberculosis medication was administered for 2 weeks. In cases of a rupture or impending rupture of the cavity, the operation was done without medication.

The main goal of the surgery was complete excision of the abscess cavity and surrounding tissue. We performed segmental rib or cartilage resection in case of any of the following. 1) Involvement of the periosteum or perichondrium such as bony destruction or periosteal granulation tissue formation was suspected. 2) The abscess cavity in the chest wall made a fistulous track to the pleural cavity forming a loculated pleural abscess. 3) The subpleural abscess cavity was large, thus requiring the complete obliteration of the pleural space.

In total, 14 rib segments were obtained from 13 patients. In 1 patient, partial resection of the sternum and clavicle was performed. After excision of the abscess, massive irrigation of the wound and meticulous obliteration of dead space using adjacent muscle mobilization or a pedicled flap was performed in every operation. Primary closure of the wound was performed in every case, and the chest wound was closed with a Penrose drain in the chest wall or a chest tube drain in the pleural cavity. The surgical methods were as follows: Abscess cavity excision in 54 (79%), abscess cavity excision with concomitant partial rib resection in 12 (17.6%), wedge resection of the lung parenchyme with abscess excision and rib resection in 1 (1.5%), and clavicular and sternal partial resection with abscess cavity excision in 1 (1.5%). No musculoskeletal reconstruction was performed ([Table 2](#T2){ref-type="table"}).

There was no operative mortality. Postoperative wound infection was noted in 16 patients (11.24%) and managed with conservative dressing and delayed wound closure. However, in 1 patient, after abscess cavity excision only, after 3 months of conservative management, reoperation for fistulectomy and partial rib excision was done. Respiratory complications such as pneumonia or atelectasis were noted in 4 patients.

The pathologic examination confirmed the disease in all cases. Typical microscopic features with epithelioid histiocytes and caseous granulomatous necrosis were found ([Fig. 2](#F2){ref-type="fig"}).

In all patients, postoperative anti-tuberculsis medication was given for 6 to 19 months including the preoperative medication periods. The regimen was based on triple (isoniazid, rifampin, ethambutol) or quadruple (triple+pyrazinamide) therapy.

The disease recurred in 5 patients (7.35%) between 6 months and 38 months postoperatively, and all these 5 patients underwent a second operation. The surgical method of the second operation in all of the recurred patients was abscess cavity excision and partial rib resection. Four patients had single site recurrence and 1 had recurrence at 2 sites. In 4 patients, the abscess cavity excision was performed at the first operation, while concomitant rib resection was performed in 1 patient at the first operation. In 3 patients, a postoperative wound problem occurred at the first operation, but in all of the patients the abscess recurred in a location other than the previous site. Only in the 1 patient with multiple lesions at the first operation did one abscess recur at a previous site and one at a newly formed site ([Table 3](#T3){ref-type="table"}).

DISCUSSION
==========

Tuberculous abscesses of the chest wall are not frequently encountered and constitute less than 10% of skeletal tuberculosis. The presentation of this disease is a progressively enlarging mass with or without pain. Sometimes abscesses make a fistulous tract to the pleural cavity and destroy underlying bone or cartilage.

There are three mechanisms in the pathogenesis of a tuberculous abscess of the chest wall \[[@B6]\]: 1) direct extension from the underlying pleural or pulmonary tuberculosis, 2) direct extension from lymphadenitis of the chest wall, and 3) hematogeneous dissemination from dormant tuberculous lesions. In the second case, mycobacterium tuberculosis in the pulmonary parenchyma or visceral pleura invades the pleural space forming pleuritis. Lymphatics in the pleural space develop by inflammation and finally communicate to the lymphatics of the chest wall, forming caseous necrosis or a fistulous tract. The third case can result from iatrogenic spread of tuberculosis to the chest wall during aspiration or drainage of tuberculous pleurisy or empyema. In our study, 22 (32.4%) patients had a history of tuberculosis or current tuberculosis. In general, retrospective studies based on medical records have the limitation that it is difficult to determine the exact mechanism of the tuberculous abscess of the chest wall.

These lesions are generally solitary, but in some patients multiple lesions were found in two or more sites. Faure et al. \[[@B6]\] reported 16 single-lesion patients of 18 patients. In our study, 60 of 64 patients had a single location.

The diagnosis of tuberculous abscess of the chest wall is difficult and often diagnosed by postoperative pathologic examination. Preoperatively, it can be confirmed by detecting acid-fast bacilli, polymerase chain reaction, or culture of pus in the abscess. Many authors recommend needle aspiration or incisional biopsy to confirm the tuberculous disease or to exclude other inflammatory disease \[[@B2],[@B4]-[@B6]\]. Faure et al. \[[@B6]\] reported a diagnostic rate of only 36.3% by needle aspiration. Sakuraba et al. \[[@B5]\] reported that 9 (62.29%) of 13 patients had positive acid-fast bacilli tests, 4 (28.57%) had positive polymerase chain reaction, and 6 (42.86%) had positive cultures from preoperative specimens. However, needle aspiration diagnosis of tuberculosis is not as reliable and some authors recommend surgical biopsy. Kim et al. \[[@B7]\] reported that only 3 of 80 patients had a preoperative bacteriologic diagnosis, and a tuberculous cold abscess was confirmed by postoperative pathologic examination in all cases. With this result, they recommended that the diagnosis can be made without a preoperative bacteriologic examination in geographic areas where the prevalence of tuberculosis remains high; instead, it can be clinically diagnosed by the clinical features of the chest wall abscess, history of pulmonary tuberculosis, and typical CT findings. Cho et al. \[[@B8]\] recommended needle aspiration or biopsy preoperatively when the patient has no past history of tuberculosis and no concomitant active pulmonary lesions, when CT findings show poorly demarcated mass lesions. In this study, only 12 patients were diagnosed preoperatively with acid-fast bacilli staining, polymerase chain reaction, or culture of bacilli, and the other cases were diagnosed with clinical information and CT findings, and confirmed with postoperative pathologic examination.

A chest CT should be performed for every patient to evaluate the extent of abscess cavities and the status of the ribs, sternum, cartilage, and pleural space. The CT also provides information on the functional state of the lung parenchyma and thoracic cavities, and concomitant diseases, and excludes other inflammatory or tumor lesions \[[@B9]\]. Brown \[[@B10]\] noted that tuberculous abscess of chest wall can be easily diagnosed in endemic geographic areas in cases with a chest wall abscess with rib destruction and an extrapleural soft tissue mass lesion on chest CT. Cho et al. \[[@B8]\] classified the CT findings of tuberculous abscess of the chest wall as follows: 1) a lesion confined to the chest wall, 2) a lesion confined to the inner chest wall beneath the ribs and also protruding into the pleural space, 3) a lesion involving most of the chest wall and also protruding into the pleural space. With this classification, they found that more a superficial location of the abscess did not exclude the risk of rib involvement. In our study, chest CT films before the mid-1990s\' were not available due to storage problems, and radiologic reports of chest CT were not sufficient to classify the type of the disease. A fistulogram with contrast media was taken in some patients, but was no longer done once the CT scan became popular in evaluating these patients.

Anti-tuberculosis medication may be very important. A few studies have reported successful treatment with anti-tuberculosis chemotherapy alone \[[@B2],[@B3],[@B11]\], but many authors have reported frequent recurrence after medication only \[[@B5],[@B6]\]. Hence, medical treatment alone is not suitable for this disease; many authors recommend a combination of medical and surgical management to reduce the recurrence. On the other hand, Faure et al. \[[@B6]\] strongly suggested chemotherapy when a tuberculous infection is confirmed or highly suspected, but fails to improve with 1 to 3 months medication, and when it worsens, surgical intervention is indicated. In our study, 31 patients were treated with anti-tuberculosis medication preoperatively with a medication period ranging from 2 to 32 weeks, but no patients were treated with medication only. Among 5 recurred patients, 2 were preoperatively medicated, and 3 were not medicated.

The methods of surgical treatment are controversial. Weissberg \[[@B12]\] mentioned in his commentary that this disease is best treated with antimicrobials and drainage, with debridement and excision reserved for the most extensive cases. The optimal surgical approach consists of excising the abscess and primary closure of the wounds, but the extent of resection is not defined. However, complete excision of the abscess including the abscess wall, fistulous tract, enlarged lymph node, and adjacent bony structure avoiding unnecessary extensive chest wall resection would be important to reduce complications and recurrence \[[@B13]-[@B15]\]. If there is any bony destruction or suspicious periosteal granulation tissue exists, if a fistulous tract overlays the rib or sternum, or for complete removal of underlying pleural abscess, the rib should be partially removed. Curettage of the infected pleural peel should be performed. After extensive debridement of the lesion, the space should be obliterated meticulously. If any dead space remains, a postoperative wound infection or chronic sinus formation can occur. In our study, we noticed a high incidence of postoperative wound infection (11.24%), which may be due to inadequate control of dead space. In 1 patient, reoperation including fistulectomy and partial rib resection was performed after 3 months of conservative management. Adequate muscle mobilization or a flap and small indwelling catheter would decrease the incidence of wound infection. Three other patients recurred among 16 postoperative wound infection patients, but at new sites.

Kim et al. \[[@B7]\] classified patients into a debridement and drainage group and a complete resection group, and they found a higher recurrence rate in the debridement and drainage group (40%) than the complete resection group (9.2%). Paik et al. \[[@B13]\] reported a 16% recurrence rate in abscess excision patients, but only a 1.6% recurrence rate in the rib resection group. These means a wide and complete resection would decrease recurrence.

Postoperative medical treatment is mandatory for an acceptable cure rate. The duration of anti-tuberculosis therapy is controversial, but, a minimum of 6 to 9 months of isoniazide- and rifampin-based therapy would be needed \[[@B14],[@B15]\]. Paik et al. \[[@B13]\] suggested medication for a minimum of 12 months especially in endemic geographical areas.

CONCLUSION
==========

We recommend preoperative medication and complete excision of tuberculous abscess of the chest wall. If periosteal involvement of the abscess is suspected, excision of the skeletal structure should be performed. To decrease postoperative morbidity, complete removal of the abscess and obliteration of any dead space is mandatory. Adequate postoperative medication may reduce the chance of recurrence.

![Chest posteroanterior (PA) view and computed tomography (CT) section in patient with a tuberculous abscess of the chest wall. (A) A 21-year-old male with a slowly growing mass reveals pleural thickening and a pleural mass-like lesion on chest PA film. (B) A CT scan shows a low attenuating density lesion in the latissimus dorsi muscle communicating with the pleural space.](kjtcs-45-177-g001){#F1}

![Microscopic findings of cold abscess showing hemorrhage and necrosis with surrounding inflammation. Multinucleated giant cells are seen (H&E, ×100).](kjtcs-45-177-g002){#F2}

###### 

Clinical features of patients with tuberculous abscess of the chest wall

![](kjtcs-45-177-i001)

Values are presented as number or number (%).

###### 

Surgical methods for tuberculous abscess of the chest wall

![](kjtcs-45-177-i002)

Values are presented as number (%).

AE, abscess excision; RR, rib resection.

###### 

Characteristics of patients who recurred after the first operation

![](kjtcs-45-177-i003)

OP, operation; AE, abscess excision; RR, rib resection.