Isolated trapdoor-type medial blowout fracture in an adult presenting horizontal diplopia treated by endoscopic endonasal approach

Abstract

Orbital blowout fracture frequently occurs along the floor or medial aspect of the orbital wall, which are the two thinnest areas of the bony orbit. True trapdoor injury of the orbit is less common and is rare as an isolated medial wall injury, because the medial orbital wall has several bony septa within the ethmoid sinus that provide support and decrease the risk of a trapdoor fracture. Additionally, the incidence of trapdoor-type blowout fracture in adults is lower than in children. In a trapdoor-type blowout fracture with restricted ocular movement, prompt diagnosis and early intervention are associated with better clinical outcomes. We encountered a case of trap door-type medial blowout fracture with horizontal eye ball movement limitation in an adult. She underwent endonasal endoscopic reduction surgery for the medial blowout fractures. Here we report this case, and suggest early diagnosis and prompt surgical exploration.

Pure Orbital Trapdoor Fractures in Adults: Tight Entrapment of Perimuscular Tissue Mimicking True Muscle Incarceration with Successful Results from Early Intervention

“…In the buckling theory, the energy of the force is first exerted on the orbital rim and is then transmitted to the orbital floor 1011. The medial wall trapdoor fractures may be more properly explained by the hydraulic theory because there is no sufficient medial orbital rim, while the buckling mechanism is more compatible to trapdoor fractures of the orbital floor 12. A blow results acute increase in intraorbital pressure and the cracked bones are temporarily displaced to the maxillary or ethmoid sinus; as a consequence, the intraorbital soft tissues prolapse through the created gap.…”

“…Despite the variations in diagnostic definitions used for OTFs, when critically reviewing the current literature, there are a few of cases/case series of pure OTFs that have been reported in adult patients (Table 1). 912151617181920 The age of oldest patient suffered from an OTF was 53 years 9. Also, isolated cases of adult patients encountered in retrospective studies whose almost all of their patients are children.…”

“…10,11 The medial wall trapdoor fractures may be more properly explained by the hydraulic theory because there is no sufficient medial orbital rim, while the buckling mechanism is more compatible to trapdoor fractures of the orbital floor. 12 A blow results acute increase in intraorbital pressure and the cracked bones are temporarily displaced to the maxillary or ethmoid sinus; as a consequence, the intraorbital soft tissues prolapse through the created gap. When the pressure subsides, the bones return back into their normal or nearnormal position, but the prolapsed soft tissues are incarcerated within the fracture line.…”

Orbital Trapdoor Fracture With Extraocular Muscle Entrapment in Adults: A Case Series

“…15,16,[18][19][20][21][22][23] We found 11 previously reported cases of orbital trapdoor fracture with extraocular muscle entrapment (Table 2). [4][5][6][7][8][9][10][11][12][13] The mean age of our patients combined with the previously reported patients (16 patients) was 26.1 years. Since 12 out of 16 patients (75.0%) were male, [4][5][6][7][8][9][10][11][12][13] there is evidence of male predominance, similar to the other types of orbital fractures.…”

“…[4][5][6][7][8][9][10][11][12][13] The mean age of our patients combined with the previously reported patients (16 patients) was 26.1 years. Since 12 out of 16 patients (75.0%) were male, [4][5][6][7][8][9][10][11][12][13] there is evidence of male predominance, similar to the other types of orbital fractures. 24 The medial and inferior rectus muscles were entrapped in 5 and 11 patients in the combined the present and previous studies, respectively.…”