On appropriate pathology for photothermal surgery.

Area of Science:

• Biomedical Engineering
• Surgical Pathology
• Photothermal Therapy

Background:

• Standard hematoxylin and eosin (H&E) staining can significantly underestimate tissue necrosis immediately following photothermal surgery.
• This underestimation poses challenges in accurately assessing surgical efficacy and potential complications.

Purpose of the Study:

• To identify an accurate and consistent histological method for evaluating tissue death after photothermal surgery.
• To determine the conditions under which H&E staining inaccuracies manifest.

Main Methods:

• Photothermal surgery was performed on ex vivo chicken livers and in vivo rat livers.
• Histopathological analysis was conducted using both H&E and NADH-diaphorase (NADH) staining at 0, 24, 48, and 72 hours post-surgery.

Main Results:

• H&E staining underestimated lesion volume by nearly an order of magnitude when performed shortly after surgery.
• Postponing histological examination for 24 hours mitigated the underestimation by H&E.
• NADH staining captured biochemical signals of enzymatic activity cessation missed by H&E at early time points.

Conclusions:

• Accurate histological assessment is crucial for avoiding false positives and reliably estimating photothermal surgical efficacy.
• NADH staining offers a more sensitive alternative to H&E for early detection of tissue damage, despite higher cost and complexity.
• Optimizing histological timing and method selection is vital for effective photothermal surgery evaluation.