Nikolai Begg tells us that complications from puncturing the skin during surgery cause 30,000 complications per year in the United States. That statistic covers cranial drilling, laparoscopic surgery and epidurals but medical puncture involves dozens of other procedures.
The trocar is the instrument that punctures the skin before surgery takes place. This is done by pushing against the skin with a blade or drill - the dangerous piece of the surgery happens when the sharp instrument has gone through the skin and has the opportunity to go deeper into important tissue.
http://www.ted.com/talks/nikolai_begg_a_tool_to_fix_one_of_the_most_dangerous_moments_in_surgery
Begg explains the phenomenon using physics. When you're pushing on a blade or drill there is an equal and opposite force resisting the puncture. In that fraction of a second when resistance is gone you're accelerating the blade, and that is the phenomenon he is trying to avoid.
This TED talk has some great straightforward talk to explain the problem. First Nikolai talks about Capri Sun pouches. Most audience members are familiar with inserting the straw into the hole in the pouch, and knowing that at any moment resistance would fall away and a massive juice gusher would erupt. He also gives a physical demonstration of a drill going into a block of wood.
During his postgraduate work Nikolai devised a mechanism that creates friction while entering the surgical membrane and then retracting the blade when the resistance is gone. Examples screened during the talk show different insertions and the retraction that takes place once the membrane is breached.
Nikolai Begg is a great speaker and really frames his TED talk to show the good he is trying to accomplish in the world. His words are inspiring and he is easily able to convince viewers that he can help to solve this problem that has been in place since 1912 and the origin of laparoscopic surgery.
http://www.ted.com/talks/nikolai_begg_a_tool_to_fix_one_of_the_most_dangerous_moments_in_surgery