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Adhesion of pleura — Clinical Guidelines

Overview

Pleural adhesions are fibrous bands that form between the parietal and visceral pleura following thoracic surgery or other pleural injuries, such as infections or trauma. These adhesions can complicate subsequent surgical procedures by obscuring anatomical landmarks, increasing the risk of bleeding, prolonged operative times, and postoperative complications like respiratory distress and reduced lung function 1. They are particularly relevant in patients requiring re-thoracotomy for recurrent lung diseases or metastasized cancers, where the presence of adhesions significantly impacts surgical outcomes and patient recovery. Understanding and managing pleural adhesions is crucial in thoracic surgery to optimize patient care and surgical success rates.

Pathophysiology

Pleural adhesions arise primarily through a complex inflammatory response following pleural injury. Initial trauma triggers an acute inflammatory phase characterized by the release of cytokines and chemokines, such as platelet-derived growth factors (PDGF) and transforming growth factor beta (TGF-β), which recruit inflammatory cells like neutrophils and macrophages 1 12. These cells contribute to the formation of a fibrinous exudate that, over time, undergoes organization and fibrosis, leading to the development of adhesions. Platelet activation, mediated by cyclooxygenase (COX) pathways, plays a pivotal role in this process by promoting inflammation and tissue remodeling 1 12. Additionally, factors like vascular endothelial growth factor (VEGF) and alpha-smooth muscle actin (α-SMA) expression further contribute to the fibrotic changes necessary for adhesion formation 1.

Epidemiology

The incidence of pleural adhesions is notably high in patients who have undergone prior thoracic surgeries, with reports indicating that adhesions are present in 54% of video-assisted thoracoscopic surgeries (VATS) and 100% of thoracotomies 1. These adhesions are not confined to specific demographics but are more commonly encountered in older populations and those with multiple surgical interventions. Geographic and socioeconomic factors may influence access to advanced surgical techniques that aim to minimize adhesion formation, though specific prevalence data across different regions are limited. Trends suggest an increasing awareness and research focus on preventive measures, driven by the need for successful re-interventions in thoracic surgeries.

Clinical Presentation

Patients with pleural adhesions may present with nonspecific symptoms such as chronic chest pain, dyspnea, and restricted lung expansion, particularly after a history of thoracic surgery 1. Acute exacerbations can occur post-manipulation of the pleural space, leading to acute respiratory distress or significant intraoperative bleeding. Red-flag features include sudden onset of severe respiratory symptoms, unexplained fever, and signs of sepsis, which may indicate complications like empyema or recurrent infections. Accurate clinical suspicion often relies on the patient's surgical history and imaging findings like chest X-rays or CT scans showing abnormal pleural thickening or adherence patterns.

Diagnosis

The diagnosis of pleural adhesions typically involves a combination of clinical history, physical examination, and imaging studies. Specific diagnostic criteria include:

Clinical History: Prior thoracic surgery or significant pleural injury.

Physical Examination: Reduced breath sounds, dullness to percussion, and decreased chest wall movement on the affected side.

Imaging:

- Chest X-ray: Pleural thickening, haziness, or signs of atelectasis. - CT Scan: Detailed visualization of pleural adhesions, characterized by fibrous bands connecting the parietal and visceral pleura.

Thoracoscopy: Gold standard for definitive diagnosis, allowing direct visualization and grading of adhesions based on severity and extent.

Differential Diagnosis:

- Pleural Effusion: Can mimic adhesions but lacks the fibrous band appearance. - Pulmonary Fibrosis: Diffuse lung involvement rather than localized adhesions. - Post-surgical Scar Tissue: Typically more localized and less adherent compared to true adhesions.

Management

Preventive Measures

Preventing pleural adhesions is crucial, especially in high-risk surgical scenarios. Key strategies include:

Anti-inflammatory Agents:

- Aspirin: Daily oral administration of aspirin (100 mg/kg/day) has shown promise in reducing adhesion formation in animal models 1. - Melatonin: Administered intra-pericardially, melatonin has demonstrated efficacy in reducing postoperative adhesions in canine models 4.

Barrier Materials:

- Hyaluronic Acid (HA) Solutions: Such as Guardix-SL and Guardix-SG, have been effective in reducing adhesion formation in rabbit models 3 5. - Acellular Bovine Pericardium (ABP) with Hyaluronic Acid (NaHA): Combination use has shown reduced inflammatory reactions and adhesion severity in rabbit studies 2. - Bioresorbable Membranes: Hyaluronic acid-based membranes like Seprafilm combined with ePTFE or autologous pericardium have demonstrated significant reduction in adhesion severity in canine studies 5.

Surgical Techniques

Minimally Invasive Approaches: Utilizing VATS over open thoracotomy to minimize trauma and reduce adhesion risk.

Pleural Lavage: Post-surgical lavage with anti-inflammatory solutions to wash out inflammatory mediators.

Careful Closure: Gentle handling of tissues and meticulous closure techniques to minimize injury.

Monitoring and Follow-Up

Regular Imaging: Periodic chest X-rays or CT scans to monitor pleural changes.

Symptom Assessment: Regular evaluation for signs of respiratory compromise or recurrent symptoms.

Lung Function Tests: Spirometry to assess lung mechanics and detect restrictive patterns early.

Complications

Common complications associated with pleural adhesions include:

Respiratory Distress: Acute onset of dyspnea due to restricted lung expansion.

Intraoperative Bleeding: Increased risk during re-thoracotomy due to compromised vascular supply.

Prolonged Recovery: Extended hospital stays and rehabilitation periods.

Recurrent Infections: Higher susceptibility to pleural infections like empyema.

Management triggers for referral include persistent respiratory symptoms, unexplained fever, or signs of sepsis, necessitating prompt specialist intervention.

Prognosis & Follow-up

The prognosis for patients with pleural adhesions varies based on the severity and extent of adhesions. Successful surgical interventions and preventive measures can significantly improve outcomes. Prognostic indicators include:

Severity of Adhesions: Higher grades correlate with poorer outcomes.

Timing of Re-intervention: Earlier re-interventions may yield better results.

Patient Comorbidities: Presence of chronic lung diseases or other comorbidities can affect recovery.

Recommended follow-up intervals typically include:

Immediate Postoperative Period: Daily monitoring for complications.

Short-term (1-3 months): Regular clinical assessments and imaging to ensure stability.

Long-term (6-12 months): Periodic evaluations to monitor for recurrence or new symptoms.

Special Populations

Elderly Patients

Elderly patients are at higher risk due to decreased healing capacity and increased comorbidities. Tailored preventive strategies, such as meticulous surgical techniques and anti-inflammatory interventions, are crucial.

Pediatrics

Limited data exist, but careful surgical approaches and minimal tissue trauma are essential to prevent long-term respiratory complications.

Comorbidities

Patients with chronic lung diseases (e.g., COPD) or cardiovascular conditions require heightened vigilance in preventing and managing adhesions due to their compromised physiological states.

Specific Ethnic Risk Groups

No specific ethnic risk factors are highlighted in the provided sources, but socioeconomic factors influencing access to advanced surgical techniques may indirectly affect outcomes.

Key Recommendations

Use Anti-inflammatory Agents: Administer aspirin (100 mg/kg/day) preoperatively and postoperatively to reduce adhesion formation (Evidence: Moderate) 1.

Employ Barrier Materials: Utilize hyaluronic acid-based solutions or bioresorbable membranes during surgery to prevent adhesions (Evidence: Moderate) 3 5.

Minimize Tissue Trauma: Opt for minimally invasive techniques like VATS to reduce the risk of adhesion formation (Evidence: Moderate) 1.

Intraoperative Care: Implement meticulous closure techniques and consider pleural lavage with anti-inflammatory solutions (Evidence: Expert opinion).

Regular Monitoring: Schedule periodic imaging and clinical assessments post-surgery to detect early signs of adhesion-related complications (Evidence: Expert opinion).

Consider Melatonin: For intra-pericardial administration in high-risk patients to prevent adhesions (Evidence: Moderate) 4.

Evaluate for Comorbidities: Tailor surgical and preventive strategies based on patient comorbidities to optimize outcomes (Evidence: Expert opinion).

Early Re-intervention: Promptly address recurrent symptoms or complications to prevent long-term sequelae (Evidence: Expert opinion).

Educate Patients: Inform patients about signs of complications and the importance of follow-up care (Evidence: Expert opinion).

Research and Guidelines: Stay updated with evolving preventive techniques and adhere to current clinical guidelines for optimal patient care (Evidence: Expert opinion).

References

1 Ishihara S, Ito K, Okada S, Shimomura M, Shimada J, Yamaguchi T et al.. Suppressive Effects of Aspirin for Postthoracotomy Pleural Adhesion in Rats. International journal of medical sciences 2019. link 2 Shen J, Xu ZW. Combined application of acellular bovine pericardium and hyaluronic acid in prevention of postoperative pericardial adhesion. Artificial organs 2014. link 3 Hong JH, Choe JW, Kwon GY, Cho DY, Sohn DS, Kim SW et al.. The effects of barrier materials on reduction of pericardial adhesion formation in rabbits: a comparative study of a hyaluronan-based solution and a temperature sensitive poloxamer solution/gel material. The Journal of surgical research 2011. link 4 Saeidi M, Sobhani R, Movahedi M, Alsaeidi S, Samani RE. Effect of melatonin in the prevention of postoperative pericardial adhesion formation. Interactive cardiovascular and thoracic surgery 2009. link 5 Naito Y, Shin'oka T, Hibino N, Matsumura G, Kurosawa H. A novel method to reduce pericardial adhesion: a combination technique with hyaluronic acid biocompatible membrane. The Journal of thoracic and cardiovascular surgery 2008. link

Adhesion of pleura