Nasolacrimal duct opening to the inferior nasal meatus in human fetuses

Retrospective analysis of congenital nasolacrimal duct obstruction outcomes in a tertiary referral center

Background

The aim of this study was to profile patients with simple and complex congenital nasolacrimal duct obstruction (CNLDO) and to determine the success rates of interventions at a third-level referral center.

Methods

In this retrospective and comparative study, medical records of patients with CNLDO were reviewed. Demographic data, types of CNLDO, surgical approach, type of silicone intubation, as well as outcome were recorded up to 3 months after the intervention. Obstruction location was identified by probing and irrigation following the American Academy of Ophthalmology (AAO) approach. Success rates were calculated for treatment approach and age group.

Results

Based on the outcome of 130 eyes with CNLDO, the overall success rate was 96%. The mean age of patients was 2.5 ± 2.2 months; 73% of cases were simple and 27% were complex CNLDO. Five children had to undergo reoperation; consequently, there was a lower success rate in the complex CNLDO (91%) than in the simple CNLDO subgroup (97%). There was a male predominance (61.5%), which was also present in the simple and complex CNLDO subgroups. The most frequent type of CNLDO was complete nasolacrimal duct obstruction (NLDO, 55.4%), followed by partial (17.7%) and bony NLDO (11.5%). In 87% of eyes, initial probing was performed followed by dacryocystorhinostomy (10%). Mono- or bi-canalicular lacrimal drainage system intubation was used in 86% of eyes.

Conclusion

The AAO-based diagnostic approach followed by an individualized treatment regimen yielded excellent success rates of 96% in unselected patients with CNLDO. These success rates were independent of patient age or gender.

Association between the developing sphenoid and adult morphology: A study using sagittal sections of the skull base from human embryos and fetuses

The developing sphenoid is regarded as a median cartilage mass (basisphenoid [BS]) with three cartilaginous processes (orbitosphenoid [OS], ala temporalis [AT], and alar process [AP]). The relationships of this initial configuration with the adult morphology are difficult to determine because of extensive membranous ossification along the cartilaginous elements. The purpose of this study was therefore to evaluate the anatomical connections between each element of the fetal sphenoid and adult morphology. Sagittal sections from 25 embryos and fetuses of gestational age 6-34 weeks and crown-rump length 12-295 mm were therefore examined and compared with horizontal and frontal sections from the other 25 late-term fetuses (217-340 mm). The OS was identified as a set of three mutually attached cartilage bars in early fetuses. At all stages, the OS-post was continuous with the anterolateral part of the BS. The BS included the notochord and Rathke's pouch remnant in embryos and early fetuses. The dorsum sellae was absent from embryos, but it protruded from the BS in early fetuses before a fossa for the hypophysis became evident. Although not higher than the hypophysis at midterm, the dorsum sellae elongated superiorly after gestational age 25 weeks. In early fetuses, the AP was located on the side immediately anterior to the otic capsule. The AT developed on the side immediately posterior to the extraocular rectus muscles. At late term, the greater wing was formed by membranous bones from the AT and AP. The AT and AP formed a complex bridge between the BS and the greater wing. A small cartilage, future medial pterygoid process (PTmed) was located inferior to the AT in early fetuses. At midterm, one endochondral bone and multiple membranous bones formed the PTmed. The lateral pterygoid process (PTlat) was formed by a single membranous bone plate. Therefore, we connected fetal elements and the adult morphology as follows. (1) Derivative of the OS makes not only the lesser wing but also the anterior margin of the body of the sphenoid. (2) Derivatives of the BS are the body of the sphenoid including the sella turcica and the dorsum sellae. (3) Most of the greater wing including the foramen rotundum and the foramen oval originate from the AT and AP and multiple membranous bones. (4) The PTmed originate from endochondral bones and multiple membranous bones, while the PTlat derive from a single membranous bone.