Lacrimal Fossa Bony Changes in Chronic Primary Acquired Nasolacrimal Duct Obstruction and Acute Dacryocystitis.

This study aims to assess the bony lacrimal fossa changes in chronic cases of primary acquired nasolacrimal duct obstruction versus acute dacryocystitis. A prospective study was performed on 25 bony lacrimal fossae of 25 eyes of 15 patients who underwent endoscopic dacryocystorhinostomy at a tertiary care Dacryology service over a period of 6 months. Ten patients with chronic PANDO (> 1 year) with bilateral involvement and five patients of unilateral acute dacryocystitis were recruited in the study. None of the patients had a history of trauma or previous surgeries or nasal disease in the past. The bone samples from the frontal process of the maxilla and the lacrimal bone were obtained during the osteotomy and subjected to routine histopathological examination. Special stains used were von Kossa, Masson trichrome, periodic acid Schiff, and Alcian blue. Immunohistochemistry was performed using CD68 antibodies. Patient demographics, clinical presentation, duration of the disease, and bony changes were analyzed in different patient subsets. The mean disease duration in the chronic PANDO subset was 3.1 years, whereas acute dacryocystitis was 6.8 days. There was no correlation between the bony changes and the laterality in the chronic subset. Periosteal thickness and fibrosis were universal in the chronic group but not in the acute dacryocystitis. There were also differences in the number of osteocytes per sq mm, osteoblast, osteoclast, bony remodeling, bony canals structure, and intrastromal fibrosis between the subsets. These changes within the chronic group increased with the duration of the disease. Interestingly, there was no evidence of any bony inflammation across the subsets in all the samples studied. Characteristic bony changes can be demonstrated in patients with chronic PANDO but not in acute dacryocystitis. The lack of bony inflammatory infiltrates may provide clues in understanding the peri-sac disease pathogenesis in acute dacryocystitis.