CT assessment of orbital volume in late post-traumatic enophthalmos

Abstract

The potential of CT to facilitate preoperative planning of reconstructive maxillofacial surgery by orbital volume quantification was analysed in 11 patients with traumatic enophthalmos as a late sequela of zygomatic fractures. We carried out biplanar CT examination of the orbits, and calculated total orbital and fat volumes for the healthy and enophthalmic sides. Displacement of the orbital floor and lateral wall was present in 11 and 7 cases respectively. Indentation of the medial wall was noted in 9 cases. Quantitative evaluation of the orbital cavity revealed a significant increase (P < 0.0188) in total volume on the enophthalmic side, the difference between the two sides ranging from 9.2% to 36.4%, mean 17.9%. The degree of enophthalmos, measured radiologically as 2.5-5 mm, correlated with the increase in orbital cavity volume (P = 0.000076). Enophthalmos was 2.5-3 mm in 7 cases (63.6%) and 3.5-5 mm in 4 (36.4%). This corresponded with a mean increase in orbital volume of 3.4 ml (12.3%) and 7.1 ml (27.8%) respectively. Fat atrophy was not an aetiological factor in the production of post-traumatic enophthalmos.

Orbital change following Le Fort III advancement in syndromic craniosynostosis: Quantitative evaluation of orbital volume, infra-orbital rim and globe position

“…Numerous studies have reported a wide range of normal values of orbital volumes, which ranged from 21 ml to 30 ml. On average orbital volumes tend to be somewhat higher in males than in females (Deveci et al, 2000;Furuta, 2001;Koppel et al, 2003;Kwon et al, 2010;Manson et al, 1986;Schuknecht et al, 1996). Consistent with the findings of Bentley et al, normal orbital volumes were found preoperatively.…”

“…Since 1985 different orbital volume measuring techniques have been described using three-dimensional (3D) computed tomography (CT) imaging (Bentley et al, 2002;Bite et al, 1985;Carr et al, 1992;Cooper, 1985;Fan et al, 2003;Furuta, 2001;Koppel et al, 2003;Manson et al, 1986;Schuknecht et al, 1996). A number of studies have shown a strong correlation of these measurements with skull measurements (Acer et al, 2009;Cooper, 1985;Deveci et al, 2000).…”

Orbital Floor Restoration

“…5 Recession of the eyeball is a rather frequent consequence, particularly when fractures of the medial wall occur. Several studies based on CT-2D and 3D scans showed that the average orbital volume is about 28.7 ml in males and 21.6 ml in females 6 , and that in post-traumatic enophthalmos its size increases by an average 12% compared to the contralateral. 7 In fact, a recession of 1 mm of the eyeball corresponds to a volume increase ranging, in vitro, between 2.8% and 5.2%, according to different Authors 8-6 (a volume increase of 1 cm 3 causes, in vivo, an enophthalmos of 0.4-0.8 mm 9-10 ).…”

Computerassistierte Verfahren in der rekonstruktiven funktionserhaltenden Orbitachirugie

“…Die Vo lu me ner mitt lung der Or bi ta nach der Me tho de der ma nu el len Seg menta ti on wur de be reits von Bite [1], Man son [13], Ra mie ri [20], Schuh knecht [24] und Whi te hou se [26] aus führ lich be schrie ben und de ren Ge nau ig keit mit 98 an ge geben.…”

“…Wei ter hin bie ten die se Tech ni ken die Mög lich keit ei ner ob jek ti ven Be wertung des tat säch lich er reich ten Er geb nisses hin sicht lich der Pla nung. Or bi ta ana lysen wer den in der Re gel an mul ti pla na ren Com pu ter to mo gram men durch ge führt [6,12,24]. Die in di vi du el le com pu teras sistier te zwei-und drei di men sio na le Or bi taana ly se, die u. a. eine na vi gier ba re stan dardi sier te vir tu el le Pla nung auf der Ba sis eines CT-Da ten sat zes er laubt, ist bis lang nur in Ein zel fäl len ver füg bar [4].…”