Cranial Drills May Not Stop Once They Reach The Brain, FDA Warns

Federal regulators warn that more than 200 patients have suffered severe injuries associated with use of certain cranial drills, which are designed to cut through the skull and stop before damaging the brain. However, the reports suggest that some of the drills may not stop once they reach the brain. 

The FDA issued a safety communication on September 28, warning that cranial perforators with an automatic clutch mechanism may fail to disengage once they hit brain tissue.

The warning is not specific to any manufacturer, as the FDA indicates this may be an industry-wide problem if neurosurgeons fail to follow very specific procedures and operating instructions.

Cranial perforators are drills that are used to create a small hole in a patient’s skull. This allows neurosurgeons to operate on the brain.

From January 2005 through August 2015, the FDA received more than 300 medical device reports (MDRs) linked to incidents where the automatic clutch mechanism on cranial perforators failed to disengage. According to the agency, this resulted in more than 200 patient injuries.

The FDA indicates that the injuries included perforation of the brain’s protective covering, bleeding, brain contusion, cerebral tissue damage and brain damage that led to decreased functioning. Patients have reportedly suffered seizures, damage to the part of the brain responsible for language, as well as increased hospitalization time and the need for additional procedures.

“Most cranial perforators are designed to automatically stop drilling after penetrating the skull to prevent the tip from unintentionally drilling or ‘plunging’ into the brain,” the FDA warning notes. “However, this clutch mechanism may fail to disengage if proper use, patient considerations, and device selection are not followed in accordance with the manufacturer’s instructions for use.”

Following the instructions properly, making sure to adjust for patient considerations, and selecting the proper device in accordance to manufacturer instructions can mitigate the risk of injury, the agency advised.

The FDA also specifically advised neurosurgeons to select the appropriate cutting accessories based on the thickness of the patient’s skull, hold the perforator perpendicular to the inner table of the skull throughout the procedure without rocking, rotating or changing the angle of the device while drilling, and to avoid using excessive pressure when near the point of perforation.

The agency also warned that neurosurgeons should be cautious about perforating areas of the skull that have variations in thickness and contour, perforating the skulls of infants, children, or elderly patients, and perforating a patient’s skull if they have disease or fragile bone or adherent underlying dura mater.

Neurosurgeons and patients are being told to report any cranial drill problems to the FDA’s Medwatch Adverse Event Reporting Program.