J Korean Orthop Res Soc.  1999 Oct;2(2):164-170.

Heat Production and Thermal Necrosis by Cortical Drilling

• Whang KS
• Chung HK
• Choi CH
• Kim JH
• Han CW
• Paik DJ

Abstract

PURPOSE: The present study was performed to determine the optimum conditions(RPM, load, sharpness of drill) for drilling human cortical bone with standard drill, and to evaluate the histological changes occuring in bone after drilling.
MATERIALS AND METHODS
in experiment I, we measured temperature elevations and the durations of temperature elevation in cadaveric femoral cortices at specific distances from the drill hole wall while drilling. The effects of drilling force, speed and new versus worn drill on the termperature were determined. In experiment II, we also measured temperature elevations in the same manner in porcine femoral cortices and evaluated the histological changes occuring in bone after drilling.
RESULTS
In experiment I, the most significant temperature elevation(68.4degrees C ) was found when worn drill was used. The lower drilling force and faster speed resulted in 55.1degrees C and 45.8degrees C temperature elevation, respectively. However, drill diameter was not a significant factor for temperature elevation. In experiment II, greater heat production was measured with worn drill, at lower drilling forces, at faster drill speed. The acute histologic reactions in bone were hyperemia, degeneration of osteocytes, change in bone stainability, tears, and fragmentation of the bone edges around the drill holes. The observed histological changes were proportional to the amount of trauma produced, that is, the greater the degree of thermal irritation, the greater the degree of histologic activity.
CONCLUSION
In cortical drilling, greater heat production was measured with worn drill, at lower drilling forces, at faster drill speed and the greater the degree of thermal irritation, the greater the degree of histologic activity. A further study of the reaction of bone to drilling at longer intervals of time at different conditions may possibly show whether aseptic thermal necrosis could be prevented.

MeSH Terms

Cadaver
Hot Temperature*
Humans
Hyperemia
Necrosis*
Osteocytes
Thermogenesis*