Possible Causes of Pleurodiaphragmatic Adhesion
Pleurodiaphragmatic adhesions result primarily from previous pleurodesis procedures, repeated thoracentesis, malignant pleural disease with high tumor burden, chest trauma with rib fractures, and inflammatory processes—though congenital adhesions can occur as remnants of physiological organogenesis.
Primary Etiologies
Post-Procedural Causes
The most common acquired cause is iatrogenic from pleurodesis attempts 1. Chemical or mechanical pleurodesis deliberately induces adhesion formation through:
- Diffuse pleural inflammation
- Coagulation-fibrinolysis imbalance favoring fibrin deposition
- Fibroblast recruitment and proliferation
- Collagen production 2
Repeated thoracentesis for diagnostic or therapeutic purposes also frequently leads to adhesion formation 1.
Malignant Disease
Malignant pleural effusions commonly develop adhesions, with 60% of patients with malignant effusions demonstrating pleural adhesions on thoracoscopy 3. Key mechanisms include:
- Higher tumor burden correlates positively with extent of adhesions
- Malignant cells disrupt normal mesothelial function
- Paradoxically, extensive adhesions reduce pleural fluid cytology yield (71% sensitivity without adhesions vs. 20% with maximum adhesions) 3
- Worse prognosis: median survival 5 months with extensive adhesions vs. 9 months with minimal adhesions 3
Traumatic Causes
Chest trauma with rib fractures produces adhesions through:
- Direct pleural injury
- Hemothorax organization
- Post-traumatic inflammation 4
Perfusion scanning reveals pathological changes before clinical manifestations appear, making it essential for assessing extent 4.
Inflammatory and Infectious Processes
Less common causes include:
- Abdominal or pelvic inflammations
- Endometriosis (particularly in catamenial pneumothorax)
- Tuberculosis
- Radiotherapy 5, 6
Congenital Adhesions
Congenital adhesions are anomalous intraperitoneal adhesions unrelated to previous disease or surgery, representing remnants of physiological organogenesis 5. These are rare but important to recognize in patients without surgical history.
Clinical Implications
Surgical Considerations
Adhesions significantly impact thoracoscopic procedures by:
- Increasing blood loss
- Prolonging operative time
- Raising risk of pulmonary fistulation from lung injury 7
- Potentially necessitating conversion to open thoracotomy 1
Diagnostic Approach
Four-dimensional CT during natural breathing can predict pleural adhesions preoperatively with 80% sensitivity and 90.3% specificity 7. Migration distance between lesion and chest wall <0.8 cm suggests adhesion presence.
Ultrasound assessment of visceral sliding helps evaluate adhesion presence and extent before video-assisted thoracoscopic surgery 8.
Important Caveats
- NSAIDs significantly impair adhesion quality after mechanical pleural abrasion (pleurodesis score 2.0 vs. 3.67 in controls, p=0.01) and should be avoided when pleurodesis is intended 9
- Pleural adhesions may restrict movement mimicking chest wall invasion on imaging, creating false-positives 10
- In peritoneal dialysis patients, pleuroperitoneal leak through diaphragmatic defects can occur, though this represents communication rather than adhesion 11