Anatomic position of the common canaliculus in patients with a large lacrimal sac

Abstract

Purpose: To study the canalicular anatomy in patients with an enlarged sac secondary to nasolacrimal duct obstruction. Methods: This study included 76 lacrimal drainage systems (LDS) of 41 adult patients with a palpable sac, which were visualized using posteroanterior digital subtraction rnacrodacryocystography. In 42 LDS, there was a palpable enlarged sac secondary to nasolacrimal duct obstruction. In 20 LDS, the sac enlargement was associated with a valve-type canalicular obstruction preventing retrograde reflux of the sac content, and in 22 LDS, there was no associated canalicular obstruction. Thirty-four LDS were either normal or had a nasolacrimal duct obstruction without a palpable sac. Results: Dacryocystography showed a common canaliculus in all LDS. In 35 (83%) of 42 LDS with a palpable sac (17 LDS with and 18 LDS without canalicular obstruction), the anatomic orientation of the common canaliculus in the superior-inferior direction showed a consistent change. The common canaliculus was bending inferiorly with a sharp angle as it was coursing to the sac. In all LDS with a nonpalpable sac, the common canaliculus had an approximately direct, horizontal, or slightly upward course to the sac. Conclusions: Lacrimal sac enlargement secondary to nasolacrimal duct obstruction changes the anatomic orientation of the common canaliculus. The canaliculus shows an acute, inferior angulation from the superior-to-inferior direction while coursing to the sac in most instances. This anatomic variation should be considered during lacrimal interventions.