Blow-out fracture of the orbit means fracture of the one of the walls without involving the rim and adjacent bones. When an object whose size is greater than the diameter of the orbital rim stikes the orbit, the globe is pushed back. There is sudden rise in intra-orbital pressure and most commonly the floor gives way outwards with herniation of peri-ocular structures into and through the fracture opening.
Materials and methods
An analysis of my series of 400 cases of orbital fractures revealed 35 cases of blow-out fractures of the orbital floor (an incidence of 8.75%) and 8 cases of blow out fracture of the medial wall (an incidence of 2%).
Discussion
Early diagnosis and treatment is extremely important as prognosis in such cases is excellent. These should preferably be treated within 7 to 10 days.
Early signs and symptoms for diagnosis of blow out fracture of the orbital floor :
The important diagnostic signs and symptoms are :- (1) Depression of the globe ; (ii) Enophthalmos : It may not be apparent of first because of haematoma which may even produce proptosis; (iii) Limitation of elevation or depression with vertial diplopia; (iv) Orbital emphysema could develop because of communication with the surrounding air sinuses ; (v) Refraction on attempted elevation indicate incarceration of the inferior rectus ; (vi) Passive traction tests under surface anaesthetic often establishes the diagnosis ; (vii) Infraorbi tal anaesthesia, hypoaesthe sia or even neuralgia are added evidences in favour of the blow out fracture of the floor of the orbit.
Technique in X-ray diagnosis
Plain X-ray or tomography is most commonly used. Special investigation used for diagnosis. However these are to be used as supportive evidences to the clinical features. Hazyness of maxillary sinuses hanging drop opacities are significant findings.
General rules of treatment with indications and contraindications.
The treatment is essentially surgical. A purely orbital approach is preferred. Where there is a large defect a combined orbito-antril approach is of advantage. With the orbital approach, support over the displaced fragment can be achieved with either autogenous bone grafts or synthetic implants.
Excellent results obtained with early diagnosis and treatment of blow out fractures of the orbital floor demonstrates the importance of carefully evaluating every patient who has a `Black eye, presence of one or more of characteristic signs should indicate the possibility of such a condition.
Decision to explore the orbit should be based on :
1. Clinical grounds which may or may betsupported by X-ray evidence.
2. If clinical signs are equivocal, it is bast to wait for 24 to 48 hours and re-evaluate. A definite increase in vertical muscle imbalance warrants exploration.
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