title: A cadaveric feasibility study of the intraorbital cannula injections of hyaluronidase for initial salvation of the ophthalmic artery occlusion.
abstract: BACKGROUND
  Phthisis bulbi may follow cosmetic filler injections. Early attempts to inject hyaluronidase into the orbit after detection of devastating signs and symptoms may potentially mitigate the complications.
  
  
  METHODS
  Cannula routes along the orbital walls were studied. Depths of injections were determined in 30 dry skulls. Deep cannula insertions were carefully performed while avoiding exiting the orbit. Forty-six cadaveric orbits with intravascular latex injection were dissected to determine injection techniques, to verify structures at risk along the routes, and to evaluate substance dispersion.
  
  
  RESULTS
  The limited depths of the superior, lateral, medial, and inferior injection routes were 4.2, 3.8, 3.6, and 2.5 cm respectively, while the orbital width was 3.9 cm. The superior parasagittal injection was effective and rarely tears the superior ophthalmic vein, artery, and the optic nerve. The medial injection should be avoided because it may injure the lacrimal sac, the ophthalmic artery, and the optic nerve. Without limited depth, the lateral injection may damage the lacrimal gland and artery and proceeds to damage the optic nerve. The inferior parasagittal injection tends to exit into the infratemporal fossa but the inferior oblique injection may be safer and effective but more complicate with the depth of 4.2 cm.
  
  
  CONCLUSIONS
  The superior parasagittal injection is a recommended simple technique with a minimal chance of vascular injury. The inferior oblique injection requires more skill but it may be safer because of the lower position. For safety reasons, depth of each cannula insertion should not exceed the orbital width.
  
  
  METHODS
  This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern BasicScience, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors http://www.springer.com/00266.
authors.affiliation: The Chula Soft Cadaver Surgical Training Center and Department of Anatomy, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, 1873 Rama 4 Road, Pathumwan, Bangkok, 10330, Thailand, tansatitapinuntrum@gmail.com.
authors.forename: Tanvaa
authors.initials: T
authors.lastname: Tansatit
authors.forename: Prawit
authors.initials: P
authors.lastname: Apinuntrum
authors.forename: Thavorn
authors.initials: T
authors.lastname: Phetudom
mesh_terms: D000328:Adult; D001157:Arterial Occlusive Diseases / Q000628:therapy*; D002102:Cadaver; D005240:Feasibility Studies; D006801:Humans; D006821:Hyaluronoglucosaminidase / Q000008:administration & dosage*; D008875:Middle Aged; D009880:Ophthalmic Artery
chemical_list: D006821:Hyaluronoglucosaminidase