Dr. Jess Mason walks you through a step-by-step process on how to perform a cranial burr hole.
Landmarks - Use CT for guidance. If no CT is available: 2 cm superior, 2 cm anterior to tragus, ipsilateral to blown pupil (temporal site). Shave the hair, prep and drape.
Reduce scalp bleeding - Inject lidocaine with epinephrine. Palpate the superficial temporal artery (STA) and remain anterior to it.
Skin incision - Make a vertical incision 3-5 cm long, down to bone. Control scalp bleeding; the frontal branch of the STA is often transected.
Insert the retractor - Insert the self-retaining scalp retractor to expose periosteum.
Expose the skull - Use the periosteal elevator to expose the skull.
Trephination - Technique varies with equipment. Have an assistant stabilize the head.
Use the perforator bit to drill through the outer table, felt as a smooth drilling motion When the drilling motion becomes jagged, switch to the conical burr to trephinate the inner table of the skull.
Note: the non-rotating hand should provide counter-torque and resist forward motion of the drill.
Hand or Electric Drill:
Set the stopper based on the CT to prevent drilling too deeply (typically 0.5-2 cm). Use the largest drill bit in the kit. Drill through the inner table of the skull.
Epidural hematoma - Epidural blood will evacuate once through the skull. Irrigate and suction the clotted blood.
Subdural hemorrhage - For a subdural bleed, make a 3-sided (or “X”) incision in the dura. Use irrigation but do NOT suction.
Skin closure - Leave a drain in place as blood will reaccumulate. Close the skin for hemostasis.
Note: Exploratory burr holes without images can be done in the following sequence: Ipsilateral temporal, contralateral temporal, ipsilateral frontal, ipsilateral parietal.