Looking for landmarks in medial orbital trauma surgery

[Applied anatomy of the medial orbital wall]

The article provides an overview of foreign and domestic studies on the anatomy of the medial wall of the orbit. Possible structural variants of the osseus structures of the medial wall and their applied clinical significance are indicated, including those having individual occurrence: additional lacrimal bone, morphological features of the structure of the fossa of the lacrimal sac, location, shape and size of the cells of the ethmoid bone, Onody cells, Haller infraorbital cell, the relative position of the anterior and posterior ethmoid foramina, the presence of additional ethmoid foramina, dysgenesis of the lacrimal bone and the orbital plate of the ethmoid bone. The anatomical prerequisites for the occurrence of intraoperative complications with surgical access to the medial wall of the orbit are described.

Biomechanical analysis of likelihood of optic canal damage in peri-orbital fracture

PURPOSE

Detection of optic canal fractures is often difficult because of the subtleness of the fracture. If we could clarify impact on which region around the orbit is likely to accompany the fracture of the optic canal, the knowledge should be useful to make early diagnosis of optic canal fractures. The present study was conducted to elucidate this issue.

METHODS

Ten finite element models were produced simulating the skulls of ten humans (8 males and 2 females; 43.8 ± 10.2 y/o). The peri-orbital area of each of the ten models was divided into eight regions in a clockwise fashion per 45 degrees. These regions were defined as Superior-Medial (0-45 degrees), Medial-Superior (45-90 degrees), Medial-Inferior (90 to 135 degrees), Inferior-Medial (135 to 180 degrees), Inferior-Lateral (180-225 degrees), Lateral-Inferior (225 to 270 degrees), Lateral-Superior (270-315 degrees), and Superior-Lateral regions (315-360 degrees), respectively. Dynamic simulation of applying traumatic energy on each of these regions was conducted. Resultant fracture patterns were evaluated using finite element analyses. Thereafter, frequencies of fracture involvement of the optic canal were evaluated for each of the eight regions.

RESULTS

The involvement of the optic canal was most frequent for the Superior-Medial region (7/10), followed by the Medial-Superior region (5/10).

CONCLUSION

Optic canal fracture is likely to occur when the area between the supra-orbital notch and the medial canthus are strongly impacted. When evident fracture or serious damage of soft tissue is observed in this area, occurrence of optic canal fracture should be suspected.

Computed tomography based analysis of the lamina papyracea variations and morphology of the orbit concerning endoscopic surgical approaches

Introduction

Radiologic evaluation is mandatory to assess the type of endoscopic approach concerning sinonasal pathology and reconstruction of fractured defects before any treatment modalities are instituted related to medial wall of the orbit.

Objective

The goal was to provide improved understanding of the lamina papyracea variations and the relationship with the orbital morphometry.

Methods

This retrospective study was performed using computed tomography scans of 200 orbits and results were compared with respect to age, sex, laterality and LP variations.

Results

Lamina papyracea variations were categorized as type A, 80.5% (161/200); type B, 16% (32/200); type C, 3.5% (7/200). For medial wall the anterior and posterior lamina papyracea heights and angles were found as 17.14 mm, 147.88° and 9.6 mm, 152.72°, respectively. Also, the length of the lamina papyracea, the mean area of the orbital floor, medial wall, lamina papyracea and orbital entrance were 33.3 mm, 7.2 cm², 6.89 cm², 4.51 cm² and 12.46 cm² respectively. The orbital height and width were measured as 35.9 mm and 39.2 mm respectively. The mean orbital cavity depth was 46.3 mm from optic foramen to the orbital entrance and the orbital volume was 19.29 cm³. We analyzed the morphometric measurements tending to increase with aging and greater in men and the relationship of them with lamina papyracea types.

Conclusion

Precise knowledge of the lamina papyracea anatomy using computed tomography is essential for safer and more effective surgery and preforming the dimensions of an implant. In this way, the postoperative complications can be decreased and the best outcome can be provided.