From the article:<p><pre><code>  &quot; ... surgeons removed some of the cells surrounding
    the nerves that run from Fidyka’s nose into his brain
    and injected them into the gap that the knife wound
    had left in his spine. ... doctors ... believed that
    if ensheathing cells were injected into his spinal
    cord they would help injured neurons to cross the
    wound, healing his spine. The surgeons had to open
    his skull and take out the ensheathing cells, a
    five-hour-long operation, and then open up his spine
    and put them back in—another five hours. &quot;</code></pre>