Cadaveric Study of Bone Tissue Temperature During Pin Site Drilling Using Fluoroptic Thermography.

Abstract

Using fluoroptic thermography, temperature was measured during pin site drilling of intact cortical human cadaver bone with a combination of 1-step drilling, graduated drilling, and 1-step drilling with irrigation of 5.0-mm Schanz pins. A 1440 revolutions per minute constant force drilling was used on tibial diaphyses while a sensor probe placed 0.5 mm adjacent to the drill hole measured temperature. Four drilling techniques on each of the tibial segments were performed: 3.5-mm drill bit, 5.0-mm Schanz pin, 5.0-mm Schanz pin in a 3.5-mm predrilled entry site, and 5.0-mm Schanz pin using irrigation. One-step drilling using a 5.0-mm Schanz pin without irrigation produced a temperature that exceeded the threshold temperature for heat-induced injury in 5 of the 8 trials. With the other 3 drilling techniques, only 1 in 24 trials produced a temperature that would result in thermal injury. This difference was found to be statistically significant (P = 0.003). The use of irrigation significantly reduced the maximum bone tissue temperature in 1-step drilling of a 5.0-mm Schanz pin (P = 0.02). One-step drilling with a 3.5-mm drill bit achieved maximum temperature significantly faster than graduated drilling and drilling with irrigation using a 5.0-mm Schanz pin (P < 0.01). One-step drilling with a 5.0-mm Schanz pin into cortical bone can produce temperatures that can lead to heat-induced injury. Irrigation alone can reduce the temperatures sufficiently to avoid damage. Predrilling can increase temperatures significantly, but the extent of any injury should be small.