Can a surgeon drill accurately at a specified angle?

Abstract

Objectives To investigate whether: • a surgeon can drill accurately a specified angle • surgeon experience, task repetition, drill bit size and perceived difficulty influence drilling angle accuracy

Methods The sample population consisted of Final-year students (n=25), non-specialist veterinarians (n=22) and board-certified orthopaedic surgeons (n=8). Each participant drilled two holes in a horizontal oak plank at 30°, 45°, 60°, 80°, 85°, 90° angles with either a 2.5mm or 3.5mm drill bit. Participants then rated the perceived difficulty to drill each angle. The true angle of each hole was measured using a digital goniometer.

Results Greater drilling accuracy was achieved at angles closer to 90°. An error of ≤±4° was achieved by 84.5% of participants drilling a 90° angle compared to approximately 20% of participants drilling a 30-45° angle. There was no effect of surgeon experience, task repetition or drill bit size on the mean error for intended versus achieved angle. Increased perception of difficulty was associated with the more acute angles and decreased accuracy, but not experience level.

Clinical significance This study shows that surgeon ability to drill accurately (within ±4° error) is limited, particularly at angles ≤60°. In situations where drill angle is critical, use of computer-assisted navigation or custom-made drill guides may be preferable.