In article <3thhkh$air at mojo.eng.umd.edu>, didier at eng.umd.edu (Didier A.
Depireux) wrote:
> During surgery on a mammal, we perform a small (5mm by 5mm) craniotomy,
> and we want to expose the underlying cortex for single electrode
recordings.
> For this, we have to incise and reflect the dura, but I am not satisfied
> with our method. Basically, we take very fine forceps and iridectomy
> scissors, rub the forceps on the dura until, at some point, something
> in the dura actually gets caught by the forceps, lift the dura, cut it
> and further resect it with the scissors.
> When you do that, it really feels like you are rubbing against the dura
> until something breaks on it, and you use the slit you just made to lift
> the dura, pia and arach. membrane and cut through the meninges. It seems
> to me that there should be a better way.
> What do people on this group do when they are faced with having to expose
> cortex? How do neurosurgeons do it with humans, without (obviously)
> damaging the underlying cortex?
For human surgery, there are dural hooks for this purpose. It consists of
a handle and two sharp points on it which are curved like a sickle and
almost horizontal. You hold the hooks against the dura and rotate. The two
hooks grab into the dura, then you lift and cut with a scissors. Fine
Science Tools (800 521-2109, FAX 800 523-2109) sell a small version that
would be suitable (Tissue Pickk, 18067-11, about $80 US). Being something
of a cheapskate (and the fact that this sort of instument is easily
damaged) I use something simple for picking up the dura of the rat spinal
cord. Take a 30 gauge needle and bend it about 90 degrees very close to
the tip. The tip is very sharp and can be used as a combination
mini-scalpel and hook for lifting up the dura. I think many neurosurgeons
use a similar technique.
