AN EXPERIMENTAL EVALUATION OF TRAUMATIC GLOBE RUPTURE

Purpose: The purpose of this investigation was to evaluate the surgeon 's ability to assess various types of globe injury, to determine the f orce necessary to rupture the globe with these types of injuries, and to determine typical orbital retraction forces used in the clinical se tting. Materials and Methods: Forty-four enucleated globes from recent ly killed cows were divided into four equal groups-one uninjured contr ol group, one group with a through-and-through scleral laceration, ano ther group with a subtotal scleral laceration, and the last group with an 18-gauge needle perforation. Twenty-seven bearded or board eligibl e oral and maxillofacial surgeons were asked to assess one sample from each of the four groups. They were then asked to retract a simulated globe on a custom-fabricated jig to determine clinical retraction forc es. Ten globes from each of the four groups were then subjected to for ces until rupture on an Instron 8501M mechanical testing unit. Accurac y of the clinical assessment was determined, and means and standard de viations of the retraction forces and globe rupture forces were derive d. Results: Through-and-through lacerations were assessed by surgeons with 100% accuracy, subtotal lacerations with 96% accuracy, uninjured globes with 74% accuracy, and perforated globes with 15% accuracy. Glo be rupture occurred at 16.72 +/- 7.87 kg in the control group, 20.36 /- 7.87 kg in the perforated group, 15.38 +/- 6.06 kg in the subtotal laceration group, and 4.94 +/- 2.56 kg in the through-and-through lace ration group. Statistically significant differences (P < .001) were no ted between the total laceration group and all other groups. The mean retraction force was 0.35 +/- 0.47 kg, which was statistically less th an the force used in all of the rupture groups (P < .001). Conclusions : Severe injuries (through-and-through lacerations) were assessed with 100% accuracy by the clinicians, and less severe injuries with less a ccuracy. Rupture forces for globes with perforations and subtotal lace rations were no different than for the control group, but substantiall y less than for the total laceration group. The simulated clinical ret raction forces were substantially more than the rupture forces in all of the groups, including the through-and-through laceration group.