Orbital Blowout Fractures: Experimental Evidence for the Pure Hydraulic Theory

J. S. Rhee
2002 Archives of Facial Plastic Surgery  
The mechanism of injury and the underlying biomechanics of orbital blowout fractures remain controversial. The "hydraulic" theory proposes that a generalized increased orbital content pressure results in direct compression and fracturing of the thin orbital bone. Objective: To examine the pure hydraulic mechanism of injury by eliminating the factor of globe-to-wall contact and its possible contribution to fracture thresholds and patterns. Materials and Methods: Five fresh human cadaver
more » ... were used for the study. In each cadaver head, 1 orbit was prepared to mimic the normal physiologic condition by increasing the hypotony of the cadaver globe to normal intraocular pressure (15-20 mm Hg) with intravitreous injection of isotonic sodium chloride solution (saline). The second orbit served as a "hydraulic control," whereby the globe and orbital contents were exenterated and replaced by a saline-filled balloon at physiologic intraocular pressure. A 1-kg pendulum measuring 2.5 cm in diameter was used to strike the cadaver heads. Drop heights ranged from 0.2 m to 1.1 m (1960 mJ to 10780 mJ energy). Each head was struck twice, once to each orbit. Direct visualization, high-speed videogra-(REPRINTED) ARCH FACIAL PLAST SURG/ VOL 4, APR-JUNE 2002 WWW.ARCHFACIAL.COM 98
doi:10.1001/archfaci.4.2.98 pmid:12020203 fatcat:hj6oiutkkvg3bpbqpckv7pbepa