Topographic and anatomical features of the nasolacrimal duct obstruction due to radioiodine treatment.

PURPOSE: To investigate the topographic and anatomical features of secondary acquired nasolacrimal duct obstruction (SALDO) due to radioiodine therapy. METHODS: Dacryocystography-computed tomography (DCG-CT) scans of the nasolacrimal ducts in 64 cases with SALDO due to radioiodine therapy and in 69 cases with primary acquired nasolacrimal duct obstruction (PANDO) were studied. The anatomical site of obstruction was located, and morphometric characteristics of the nasolacrimal ducts were calculated: volume, length, and average sectional area. The statistical analysis was performed using the t-criterion, ROC analysis, and the odds ratio (OR). RESULTS: The mean nasolacrimal section area was 10.7 ± 0.8 mm2 in patients with PANDO and 13.2 ± 0.9 mm2 in patients with SALDO due to radioiodine therapy (p = 0.039); the AUC value in ROC analysis for this parameter was 0.607 (p = 0.037). The development of "proximal" obstruction including lacrimal canaliculi obstruction and obstruction at the site of the lacrimal sac was 4.076 times more likely (CI: 1.967-8.443) in patients with PANDO than in patients with SALDO due to radioactive iodine exposure. CONCLUSIONS: By comparing CT scans of the nasolacrimal ducts, we observed that in SALDO obstruction due to radioactive iodine therapy is predominantly "distal," while in PANDO it is more often "proximal." The development of obstruction within SALDO is followed by more pronounced suprastenotic ectasia.

Morphological Characteristics of the Lacrimal Apparatus in its Obstruction of Various Genesis.

Secondary acquired lacrimal duct obstruction (SALDO) is one of the complications of radioiodine therapy. The material was obtained during endoscopic dacryocystorhinostomy with revision of Hasner's valve in patients with PANDO (n = 7) in the distal segments of the nasolacrimal duct and in patients with SALDO (n = 7) after radioactive iodine therapy. The material was stained with hemotoxylin and eosin, alcyan blue, and by Masson method. Morphological and morphometric analyses were performed in semi-automatic mode. The results of histochemical staining of sections were translated into points taking into account the area and optical density (chromogenicity). The differences were considered significant at p < 0.05. It was shown that the nasolacrimal duct sclerosis is significantly lower (p = 0.029) in patients with SALDO than in patients with PANDO while fibrosis in the lacrimal sac is the same in patients of the compared groups.