CORR Insights®: To Improve Your Surgical Drilling Skills, Make Use of Your Index Fingers

Where Are We Now?

The mentor-apprentice relationship seen as the basis of surgical training 30 years ago has given way to technological advancements like surgical simulation training, which is becoming more-commonly integrated into some residency programs’ curricula [5]. I believe the logical, practical study by Langeveld and colleagues [4] is another such advancement.

Drilling, sawing, and reaming are fundamental orthopaedic surgical skills, and as such, they are emphasized during training. To date, studies on drilling have generally focused on the mechanics and design of drill bits, their biological effects, and the design of screw threads [6]. By contrast, few in-vitro or in-vivo studies have evaluated the art and science of drilling [3, 8], and none to my knowledge have focused on improving the drilling skills of novice surgeons.

Enter Langeveld and colleagues [4], who conducted an intuitive study on bone models (Sawbones®, Malmo, Sweden) that could change the way we teach drilling to our trainees. The authors tested four different drilling techniques, all of which involved the index fingers of both hands and found that drilling results were improved most by aligning the index finger with the drill bit and using the middle finger to pull the trigger while drilling toward the index finger of the opposite hand [4]. By advising to use the pointing fingers of both hands, Langeveld and colleagues have indirectly advocated for the principles of triangulation and improved drilling results in the study confirmed that the human brain can be trained to navigate better in a three-dimensional (3-D) space.

Where Do We Need To Go?

Drill bits are the most-common instrument to break during orthopaedic trauma surgery [7]; however, because drill bits are inexpensive, preventing this rare event (0.35% in that study [7]) really is not the main reason we should help our trainees to improve their skills. Anyone who has spent time with orthopaedic trainees realizes that drilling can be a dangerous maneuver when performed near nerves and arteries, and because of underreporting, we probably will never know how many neurovascular injuries really are caused by inexpert use of the drill. I suspect we all can agree that whatever we can do to make this important technical skill safer will be effort well spent. Langeveld and colleagues [4] have given us a good start. Remaining unanswered questions include whether and how to adjust drill technique when drilling perpendicularly or at an angle to cortical bone or when working with bones that are especially convex (which can result in skiving of the bit [1]), how to minimize soft-tissue damage during drilling in different anatomic regions, and how to prevent cortical blowout on the far side of a bone when drilling, which can reduce the strength of internal fixation constructs.

Regarding the protection of soft tissues, if one were to adopt the technique represented by Langeveld and colleagues here [4], new designs for protective drill sleeves may be needed; since their recommended technique involves using the nondominant hand as a pointer, that hand may not be free to hold drill sleeves as they now are designed.

How Do We Get There?

To bridge these gaps and to translate meaningful laboratory studies to surgical practice, we need to determine how we can adjust our drill technique when drilling perpendicularly or at an angle to cortical bone or when working with bones that are especially convex (which can result in skiving of the bit). We can do this by developing a laboratory study that tests a pilot drill bit that uses ultrasound rather than conventional rotator torque and is sharp as well as strong enough to withstand axial and bending forces to avoid breakage

We also need to determine how to minimize soft-tissue damage during drilling in different anatomic regions. Plunging can be decreased by introducing modern automated technology into drills and drill bits. If the setting of drilling distance (based on the preoperative templating from radiographs and CT scans) is fed on the drill, the drill should automatically stop at the desired distance of drilling. We would need laboratory studies on Sawbones®/cadaveric bones to trial these ideas and translate them to clinical use in the orthopaedic setting.

Finally, we need to determine how to prevent cortical blowout on the far side of a bone when drilling, which can reduce the strength of internal fixation constructs. Cortical blowouts usually occur in the far cortices of osteopenic/osteoporotic bone. The axial force applied on the drill bit and RPM of the drill bit should be customized based on the quality of bone rather than box-standard. Rotatory ultrasonic bone drilling is an option but needs to be translated to clinical practice [2]. Utilizing 3-D printing of real fractures based on CT scans and preoperatively planning the execution of the internal fixation will limit the intraoperative guess work and could prevent cortical blowout on the far side of a bone.