A new electrocautery pleural biopsy technique using an insulated-tip diathermic knife during semirigid pleuroscopy

The biopsy size obtained with standard flexible forceps (SFF) during semirigid pleuroscopy is often insufficient for pathological examination. An insulated-tip diathermic knife (IT knife) allows safe resection of a larger lesion during gastrointestinal endoscopy. We sought to validate an electrocautery pleural biopsy technique using the IT knife during semirigid pleuroscopy. We compared the diagnosis of specimens obtained using the IT knife and SFF in 20 subjects with unexplained pleural effusion, and reviewed pleuroscopic parameters such as complications, procedure time, and diameter of the specimens.

After injecting saline with lidocaine and epinephrine below the affected pleura, the lesion was incised in a circular shape with full thickness by manipulating the IT knife.

Diagnostic yields from specimens obtained with the IT knife and SFF were 85% (17 of 20 cases) and 60% (12 of 20 cases), respectively. The IT knife biopsy was superior to SFF in 8 of 20 patients (malignant pleural mesothelioma in three, nonspecific inflammation in two, metastatic breast cancer in one, and tuberculosis in one). These pleural lesions revealed thickened, smooth abnormal appearances. The overall diagnostic yield for both IT knife and SFF was 100%. Median time of the procedure, from first pleural injection to specimen removal, was 21 min (range 12-92 min), and median diameter of specimen was 13 mm (range 6-23 mm). There were no severe complications during the procedure.

Electrocautery biopsy using the IT knife during semirigid pleuroscopy has great potential for diagnosing smooth abnormal pleura which are difficult to biopsy with SFF.