Dear Editor,

In this technical note, the authors describe the management of a right inferior MCA-trunk tear after a cotton patty became entangled in the drill, which then caused the MCA branches to wrap around the drill [2]. This occurred during an intradural anterior clinoidectomy as part of the clipping of a posterior communicating and anterior choroidal artery aneurysm clipping. The tear could be primarily repaired with interrupted 10.0 stitches, without causing an obvious change in lumen diameter. Two small branches were avulsed and were coagulated; the 2 aneurysms were subsequently successfully clipped and the patient woke up without a neurological deficit.

We would like to thank the authors for publishing this complication. A recent systematic on the management of large vessel injury in open skull base surgery yielded only 12 articles [5]. This highlights a phenomenon of complication underreporting, whilst the educational value of these reports is tremendous.

No comments can be made on the technical expertise with which this complication was handled. The key points are all valuable and clearly written by an experienced surgeon.

However in our opinion the main message of this report should be: when the drill goes in, every cottonoid patty in the operative field should be removed. ‘Drill in, patty out!’ is one of the principles in skull base and cerebrovascular surgery. The risk of turning a patty into a brush cutter or a projectile when contacting a high-speed drill bit is well described [1, 3, 4, 6]. Apart from the extradural clinoidectomy, some alternative strategies to protect the adjacent brain are spatulas, reflecting the dura or using wet gelfoam [3, 4]. By applying this principle, similar (or worse) complications can be prevented by surgeons with less experience.