Mapping the Posterior Ledge and Optic Foramen in Orbital Floor Blowout Fractures

Yu Cong Wong; Doreen S.L. Goh; Celine S.Y. Yoong; Cowan Ho; Elijah Z. Cai; Angela Hing; Hanjing Lee; Vigneswaran Nallathamby; Yan L. Yap; Jane Lim; Sundar Gangadhara; Thiam C. Lim

doi:10.1055/a-2074-2092

Archives of Plastic Surgery, Inhaltsverzeichnis

CC BY 4.0 · Arch Plast Surg 2023; 50(04): 370-376
DOI: 10.1055/a-2074-2092

Pediatric/Craniomaxillofacial/Head & Neck

Original Article

Mapping the Posterior Ledge and Optic Foramen in Orbital Floor Blowout Fractures

Authors

Yu Cong Wong

¹Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
Doreen S.L. Goh

¹Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
Celine S.Y. Yoong

¹Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
Cowan Ho

¹Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
Elijah Z. Cai

²Department of Surgery, Division of Plastic, Reconstructive and Aesthetic Surgery, National University Health Systems, Singapore
Angela Hing

¹Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore

³Department of Surgery, Yong Loo Lin School of Medicine, National University Health Systems, Singapore
Hanjing Lee

²Department of Surgery, Division of Plastic, Reconstructive and Aesthetic Surgery, National University Health Systems, Singapore
Vigneswaran Nallathamby

⁴Department of Surgery, Division of Plastic, Reconstructive and Aesthetic Surgery, Ng Teng Fong General Hospital, Singapore
Yan L. Yap

²Department of Surgery, Division of Plastic, Reconstructive and Aesthetic Surgery, National University Health Systems, Singapore
Jane Lim

²Department of Surgery, Division of Plastic, Reconstructive and Aesthetic Surgery, National University Health Systems, Singapore
Sundar Gangadhara

⁵Department of Ophthalmology, Division of Orbit and Oculofacial Surgery, National University Hospital, Singapore
Thiam C. Lim

¹Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore

²Department of Surgery, Division of Plastic, Reconstructive and Aesthetic Surgery, National University Health Systems, Singapore

³Department of Surgery, Yong Loo Lin School of Medicine, National University Health Systems, Singapore

Abstract

Background The posterior ledge (PL) is a vital structure that supports the implant posteriorly during orbital floor reconstruction. This study describes a technique for mapping the PL in relation to the infraorbital margin (IM) in patients with orbital floor blowout fractures. This study establishes the location of the optic foramen in relation to the PL.

Methods Facial computed tomography (FCT) scans of 67 consecutive patients with isolated orbital floor blowout fractures were analyzed using Osirix. Planes of reference for orbital fractures, a standardized technique for performing measurements on FCT, was used. Viewed coronally, the orbit was divided into seven equal sagittal slices (L1 laterally to L7 medially) with reference to the midorbital plane. The distances of PL from IM and location of optic foramen were determined.

Results The greatest distance to PL is found at L5 (median: 30.1 mm, range: 13.5–37.1 mm). The median and ranges for each slice are as follows: L1 (median: 0.0 mm, range: 0.0–19.9 mm), L2 (median: 0.0 mm, range: 0.0–21.5 mm), L3 (median: 15.8 mm, range: 0.0–31.7 mm), L4 (median: 26.1 mm, range: 0.0–34.0 mm), L5 (median: 30.1 mm, range: 13.5–37.1 mm), L6 (median: 29.0 mm, range: 0.0–36.3 mm), L7 (median: 20.8 mm, range: 0.0–39.2 mm). The median distance of the optic foramen from IM is 43.7 mm (range: 37.0– 49.1) at L7.

Conclusion Distance to PL from IM increases medially until the L5 before decreasing. A reference map of the PL in relation to the IM and optic foramen is generated. The optic foramen is located in close proximity to the PL at the medial orbital floor. This aids in preoperative planning and intraoperative dissection.

Keywords

orbital fractures - blowout fractures - optic nerve

Volltext

Referenzen

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