Rotary ultrasonic bone drilling: Improved pullout strength and reduced damage

Area of Science:

• Orthopedics
• Biomaterials Engineering
• Surgical Innovation

Background:

• Bone drilling is crucial for fracture repair but generates microcracks, impairing bone healing and screw fixation.
• Existing conventional surgical bone drilling (CSBD) methods can lead to significant bone damage.
• Minimizing microcracks and enhancing screw stability are critical for successful osteosynthesis.

Purpose of the Study:

• To investigate and compare the microcrack generation and screw pullout strength between CSBD and rotary ultrasonic bone drilling (RUBD).
• To evaluate the impact of drilling parameters on bone surface integrity.
• To assess the biomechanical performance of screws inserted into RUBD-generated bone holes.

Main Methods:

• In-vitro study using porcine bone.
• Comparison of conventional surgical bone drilling (CSBD) with rotary ultrasonic bone drilling (RUBD) using a diamond-coated hollow tool.
• Scanning electron microscopy (SEM) for microcrack and surface morphology analysis.
• Biomechanical axial pullout testing of cortical bone screws.

Main Results:

• RUBD demonstrated a significant reduction in the number and size of microcracks compared to CSBD.
• Higher rotational speeds and lower feed rates during drilling correlated with reduced bone damage.
• Axial pullout strength of screws in RUBD-drilled holes was 55-385% higher than in CSBD-drilled holes.

Conclusions:

• Rotary ultrasonic bone drilling (RUBD) is a superior technique for creating bone holes with minimal microdamage.
• RUBD enhances the biomechanical stability of cortical bone screw fixation.
• This novel drilling method holds promise for improving surgical outcomes in orthopedic procedures.