How should pleurodiaphragmatic adhesion be diagnosed and managed?

Diagnosis and Management of Pleurodiaphragmatic Adhesion

Diagnostic Approach

Pleurodiaphragmatic adhesions should be diagnosed using respiratory dynamic CT (RD-CT) or four-dimensional CT during natural breathing, which provides superior preoperative detection compared to standard imaging, with specificity reaching 86.8% when the CT-Respiration Ratio is less than 0.65. 1, 2

Imaging Modalities

• Respiratory dynamic CT (RD-CT) should be performed with inspiration and expiration phases to assess synchronous motion during respiration, as sliding score correlates inversely with adhesion severity 1
• For patients who cannot maintain constant respiratory rhythm (elderly, those with respiratory dysfunction), four-dimensional CT during natural breathing is equally effective, measuring migration distance between the lesion and chest wall (mean 0.8 ± 0.2 cm with adhesions vs 2.6 ± 1.8 cm without) 2
• Transthoracic ultrasonography outperforms standard CT for detecting septations, with 81-88% sensitivity and 83-96% specificity, and should be used when loculated collections are suspected 3
• Standard chest radiographs may show ill-defined or tented diaphragmatic outlines, though this can represent normal anatomical variation of the pulmonary ligament rather than pathological adhesions 4

Clinical Context Assessment

• Obtain detailed asbestos exposure history, as diffuse pleural thickening with adhesions occurs in 9-22% of asbestos-exposed workers and increases with time from first exposure 3
• Assess for prior pleural inflammation or effusion, as adhesions commonly develop following acute pleuritis, repeated thoracentesis, or previous pleurodesis attempts 3
• Evaluate dyspnea severity in relation to the extent of pleural involvement, as adhesions causing restrictive impairment may reduce FVC by 270 ml regardless of radiographic extent 3

Management Strategy

Conservative Management

For asymptomatic or minimally symptomatic pleurodiaphragmatic adhesions discovered incidentally, observation with serial pulmonary function testing is appropriate, monitoring for progressive restrictive impairment. 3

• Perform baseline spirometry to document FVC and establish restrictive pattern (characteristic preservation of diffusing capacity with reduced lung volumes) 3
• Schedule follow-up pulmonary function tests every 6-12 months to detect progression, as diffuse pleural thickening can cause FVC decrements two-fold greater than circumscribed plaques 3
• Monitor for development of pachypleuritis (extensive bilateral fibrosis with active inflammation), which may progress to ventilatory failure and require surgical intervention 3

Surgical Intervention

When adhesions cause significant symptoms or complicate planned thoracic procedures, thoracoscopic adhesiolysis is preferred over open thoracotomy, though extensive adhesions may necessitate conversion. 3

Preoperative Planning

• Use RD-CT or 4D-CT findings to determine surgical approach, as sensitivity reaches 77.8% in patients with CT-Respiration Ratio <0.65 1
• Recognize that extensive dorsal pleural adhesions, involvement of ≥2 areas including dorsal pleura, or extensive mediastinal adhesions predict prolonged air leak (odds ratio 2.83) and should prompt patient counseling about extended hospitalization 5
• Prepare for conversion to open thoracotomy when preoperative imaging suggests dense adhesions preventing safe thoracoscopic visualization 3

Surgical Technique

• Medical thoracoscopy allows direct visualization and biopsy of visceral and diaphragmatic pleura under local anesthesia with conscious sedation, reducing diagnostic uncertainty to <10% 3
• VATS requires general anesthesia and single-lung ventilation but enables more extensive adhesiolysis using multiple ports 3
• When adhesions prevent safe VATS insertion or adequate visualization, convert to open thoracotomy rather than risk complications from inadequate exposure 3
• Use bipolar electrocautery or ultrasonic devices instead of monopolar cautery to minimize thermal injury and reduce risk of further adhesion formation 3

Adhesion Prevention Strategies

• Apply hyaluronate carboxymethylcellulose (Seprafilm®) barriers, which decrease reoperation for adhesive complications by 51% (RR 0.49; 95% CI 0.28-0.88) 6
• Consider icodextrin (Adept®) liquid barrier for laparoscopic approaches, reducing recurrent adhesive complications (RR 0.20; 95% CI 0.04-0.88) 6
• Avoid starch-powdered gloves and minimize foreign body reactions that aggravate adhesion formation 3

Management of Trapped Lung

When adhesions cause trapped lung (inability to achieve complete lung expansion), pleurodesis is contraindicated and indwelling pleural catheter placement should be considered instead. 3

• Suspect trapped lung when initial pleural fluid pressure is <10 cm H₂O at thoracentesis or when pressure exceeds 19 cm H₂O after removing 500 ml of fluid 3, 7
• Confirm with bronchoscopy to exclude endobronchial obstruction before attributing non-expansion to pleural restriction 3
• Place indwelling pleural catheter (IPC) for symptomatic relief, as 42.3% achieve spontaneous pleurodesis over median 126 days despite trapped lung 3

Special Considerations for Decortication

• Decortication may be beneficial in pachypleuritis with bilateral involvement causing ventilatory failure, cor pulmonale, or CO₂ retention 3
• Expect prolonged air leak (>7 days) in 32.6% of cases, with higher rates when extensive adhesions are present 5
• Postoperative pneumoperitoneum after diaphragmatic manipulation is expected and does not require surgical re-exploration absent peritonitis 8

Critical Pitfalls to Avoid

• Do not attempt pleurodesis without confirming complete lung expansion, as failure to expand indicates trapped lung or endobronchial obstruction requiring alternative management 3, 7
• Do not rely solely on standard CT for detecting septations or adhesions, as transthoracic ultrasound provides superior sensitivity (81-88% vs 71%) 3
• Do not dismiss tented diaphragmatic contours as always pathological, since normal anatomical variation of the pulmonary ligament can produce similar radiographic appearance 4
• Do not underestimate functional impact of diffuse pleural thickening, as even minimal costophrenic angle blunting can cause significant FVC reduction comparable to extensive involvement 3
• Do not proceed with VATS when preoperative imaging shows extensive adhesions without preparing for conversion to open thoracotomy, as inadequate visualization increases complication risk 3