Course of the Bony Canal Associated with High-Positioned Supraorbital Foramina: An Anatomic Study to Facilitate Safe Mobilization of the Supraorbital Nerve

Abstract

Objective: In the dissection of the superior orbital rim, the supraorbital foramen must be released to preserve the supraorbital nerve. The aim of this study was to clarify the spatial dimensions of a high-positioned foramina to allow for the safe performance of this maneuver.

Methods: We examined 90 orbital sides. In the detected foramina we measured the distance between the superior orbital rim and the inferior margin of the foramen (height), and between the rim and the anterior margin of the opening of the foramen in the orbital roof (depth). To evaluate the inclination of the canal, we calculated the height:depth ratios. Foramina with a height exceeding 2.0 mm were defined as high-positioned and measurements between low- and high-positioned foramina were compared.

Results: We were able to find 37 foramina in 32 orbital sides; 25 (67.6%) were low-positioned and their height ranged from 0.5-1.9 mm (mean: 1.16 mm); 12 (32.4%) were high-positioned with a height ranged from 2.0-11.9 mm (mean: 4.0 mm). The depth in low- and high-positioned foramina ranged from 0.5-3.2 mm (mean: 1.44 mm) and 0.7-6.5 mm (mean: 2.13 mm), respectively. The height:depth ratio was greater in high-positioned foramina, ranging from 1.03-3.38 (mean: 2.19), than in low-positioned foramina where it ranged from 0.4-2.2 (mean: 0.98).

Conclusion: The height:depth ratio in high-positioned foramina, an approximate mean value of 2, and the absence of a value less than 1, was considered to indicate a steep canal inclination. To avoid postoperative forehead numbness, anatomic information regarding the course of the bony canal must be considered.

Key words

anatomy - skull base surgery - supraorbital foramen - supraorbital nerve

References

• 1 Andersen NB, Bovim G, Sjaastad O. The frontotemporal peripheral nerves. Topographic variations of the supraorbital, supratrochlear and auriculotemporal nerves and their possible clinical significance.  Surg Radiol Anat. 2001;  23 97-104
• 2 Knize DM. A study of the supraorbital nerve.  Plast Reconstr Surg. 1995;  96 564-569
• 3 Malet T, Braun M, Fyad JP, George JL. Anatomic study of the distal supraorbital nerve.  Surg Radiol Anat. 1997;  19 377-384
• 4 Beer GM, Putz R, Mager K, Schumacher M, Keil W. Variations of the frontal exit of the supraorbital nerve: An anatomic study.  Plast Reconstr Surg. 1998;  102 334-341
• 5 Berry AC. Factors affecting the incidence of non-metrical skeletal variants.  J Anat. 1975;  120 519-535
• 6 Keskil S, Gozil R, Calguuner E. Common surgical pitfalls in the skull.  Surg Neurol. 2003;  59 228-231
• 7 Saylam C, Ozer MA, Ozek C, Gurler T. Anatomical variations of the frontal and supraorbital transcranial passages.  J Craniofac Surg. 2003;  14 10-12
• 8 Webster RC, Gaunt JM, Hamdan US, Fuleihan NS, Giandello PR, Smith RC. Supraorbital and supratrochlear notches and foramina: Anatomical variations and surgical relevance.  Laryngoscope. 1986;  96 311-315
• 9 Cheng ACO, Yuen HKL, Lucas PW, Lam DSC, So KF. Characterization and localization of the supraorbital and frontal exits of the supraorbital nerve in Chinese: An anatomic study.  Ophthal Plast Reconstr Surg. 2006;  22 209-213
• 10 Riefkohl R, Kosanin R, Georgiade GS. Complications of the forehead-brow lift.  Aesth Plast Surg. 1983;  7 135-138
• 11 Agthong S, Huanmanop T, Chentanez V. Anatomical variations of the supraorbital, infraorbital, and mental foramina related to gender and side.  J Oral Maxillofac Surg. 2005;  63 800-804
• 12 Aziz SR, Marchena JM, Puran A. Anatomic characteristics of the infraorbital foramen: A cadaver study.  J Oral Maxillofac Surg. 2000;  58 992-996
• 13 Cutright B, Quillopa N, Schubert W. An anthropometric analysis of the key foramina for maxillofacial surgery.  J Oral Maxillofac Surg. 2003;  61 354-357
• 14 Cuzalina AL, Holmes JD. A simple and reliable landmark for identification of the supraorbital nerve in surgery of the forehead: An in vivo anatomical study.  J Oral Maxillofac Surg. 2005;  63 25-27
• 15 Hanihara T, Ishida H. Frequency variations of discrete cranial traits in major human populations. IV. Vessel and nerve related variations.  J Anat. 2001;  199 273-287
• 16 Perneczky A, Muller-Forell W, Lindert E van, Fries G. Current strategies in keyhole and endoscope-assisted microneurosurgery. Keyhole Concept in Neurosurgery. With Endoscope-Assisted Microsurgery and Case Studies. Stuttgart, New York: Thieme 1999: 37-51
• 17 Slade CS, Cohen SP. Elicitation of the oculocardiac reflex during endoscopic forehead lift surgery.  Plast Reconstr Surg. 1999;  104 1828-1830

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