Search

Obstruction of the lacrimal drainage apparatus may result in excessive tearing or epiphora. This may occur as a result of a traumatic injury or accumulation of debris, mucus, or pus. In nuclear dacryoscintigraphy, a radioactive solution is introduced into the conjunctival sac by pipette and allowed to follow the flow of the tear solution through the lacrimal drainage system. This article will review normal lacrimal anatomy and indications for nuclear dacryoscintigraphy in oral and maxillofacial surgery.

Background: Magnetic resonance imaging (MRI) has excellent spatial and soft tissue resolution in the periocular and orbital region, especially when combined with surface coil techniques. Other methods, including computed tomography, dacryocystography, and dacryoscintigraphy provide limited information in the area of the lacrimal drainage system. Magnetic resonance imaging was used in conjunction with other imaging modalities to compare the anatomic detail and clinically relevant information obtained about various pathologic processes in the lacrimal drainage area. Methods: Patients with a variety of lacrimal drainage disorders underwent MRI with either head or surface coils. Contrast agents also were used in selected cases. Seven case reports are presented. Results: Magnetic resonance imaging provided detailed information about local anatomy, extent of pathology, and, in some cases, etiology of the pathology. Conclusions: Magnetic resonance imaging with surface coils provides detailed soft tissue information when compared with dacryocystography and computed tomography in the area of the lacrimal drainage system. In selected cases of lacrimal drainage system pathology, MRI may provide data that affect patient management.

To document the change in drainage of tears that occurs with blinking, the authors evaluated 17 lacrimal systems of 12 individuals with dacryoscintigraphy. A significant difference in tear drainage was found by keeping the eyelids closed during the first 2 minutes after drop placement (P less than 0.03), but not from 2 to 5 minutes (P greater than 0.4). Retardation of tear drainage after droplet placement can be achieved by simple eyelid closure for 2 minutes.

Nuclear dacryocystography is a simple, relatively harmless method of evaluating patients suspected of having abnormalities of the nasolacrimal drainage system. A drop of normal saline containing approximately 100 μ Ci of 99m Tc-pertechnetate is placed on the conjunctiva near the lateral canthus, and serial scintigrams are obtained as the pertechnetate flows along the tear strips, through the nasolacrimal drainage system, into the nasal fossa. By using a pinhole collimator with a very small aperture (1 mm), the canaliculi, the nasolacrimal sac, and the nasolacrimal duct are readily visualized. When flow is impaired, the site of obstruction can often be identified. Contrast dacryocystography provides similar information but requires the injection of contrast material directly into a canaliculus. Nuclear dacryocystography provides good functional assessment of nasolacrimal drainage but has serious shortcomings in defining pathologic anatomy. Contrast dacryocystography outlines the anatomy well but often misses minor obstructions. The two studies are complementary and together provide an effective means of evaluating the nasolacrimal drainage system.