Blow-out fractures of the orbit, most commonly involving the floor and/or the medial wall, can occur following blunt trauma to the face. They may result in an increased incidence of ocular injuries relative to other orbito-zygomatic complex fractures (Barry et al., 2008).
The sequelae of orbital blow-out fractures include infra-orbital nerve sensory deficit, and diplopia secondary to extra - ocularmuscle involvement (entrapment, ischaemia, haemorrhage, and nerve injury) (Burnstein, 2002).
Orbital floor fractures were first described by MacKenzie in1844. The term “blow-out fracture” was established in 1957, when Smith and Regan described inferior rectus muscle entrapment with decreased ocular motility in the setting of an isolated orbital floor fracture (Ducic and Verret, 2009)
The treatment of orbital floor fractures remains a controversy and there is no widely accepted consensus regarding indications and surgical technique. There are several accepted indications for immediate repair, comprising soft tissue entrapment with a non-resolving oculocardiac reflex or early enophthalmos (Burnstine, 2002).
Traditionally, a transorbital approach to the orbital floor via various lower eyelid incisions has been applied in the field of plastic surgery. This approach permits direct access to and repair of the fractured site. However, it has a limitation in terms of surgical exploration of the posterior aspect of the orbit due to the risk of damaging the optic nerve (Mohadjer et al, 2006).
On the other hand, subciliary and transconjunctival approaches have high incidences of cosmetic complications (Ridgway et al, 2009).
A transmaxillary approach to the orbital floor was first reported in the 1970s (Walter, 1972) and became established thanks to advances in endoscopic sinus surgery (Saunders et al, 1997).
However, controversy remains concerning the method for support of the orbital floor after elevation of the orbital contents. Some investigators used an implant such as autogenous bone (Mohammad et al, 1998 - Nishiike et al, 2005), titanium mesh (Chen CT and Chen YR, 2001), or a resorbable plate (Persons and Wong, 2002 – Strong, 2004)to reconstruct the orbital floor defect after transmaxillary reduction. Meanwhile, others inserted a urethral balloon catheter into the maxillary sinus to support the orbital floor (Miki, 2004 - Otori et al, 2003).
Enophthalmos may present early if greater than half the orbital floor is involved in a fracture, and this may also prompt early intervention (Hawes and Dortzbach, 1983). However, in the absence of those situations that require immediate intervention, a two-week period of observation is often followed to allow for resolution of oedema and haemorrhage. Disturbance of ocular motility may not only be caused by entrapment of extra-ocular muscles and associated soft tissues (Burnstein, 2002).
The key to successful surgical repair of these injuries is adequate exposure, visualization of the posterior bone shelf, and anatomical reconstruction of the entire defect. The traditional approach exposes the orbital floor, but it is difficult to see the posterior edge of the fracture and the condition of the herniated tissue before and after reduction of the orbital contents. Posterior dissection is the most difficult manoeuvre and is a common reason for failure of orbital floor repair. Transmaxillary endoscopic visualization of the orbital floor offers an excellent view of the entire defect and the surgical reconstruction (Kakibuchi et al, 2004).
Reconstruction of orbital floor fractures obviates the need for external scars and thus eliminates the risk of ectropion. In patients with a posterior floor fracture or a fracture with a limited posterior shelf, an endoscopic approach may be advantageous for visualization and implant positioning. Reconstruction of isolated orbital floor fractures can be performed safely and effectively through an endoscopic technique. (Ducic and Verret, 2009 - Ikeda et al, 1999).
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