Ideally, when there is a lumbar drain in place (I'm assuming that is the type of drain you are talking about) -- this will help divert the spinal fluid into the drain, and take the pressure off of the healing wound.
And when the healing wound is sealed up enough, then the drain can be removed, which may be several days.
This often will help prevent leakage out of a healing wound, and as long as there are no other issues, this should have a good chance of success. If this doesn't work, then a longer period of drainage into the lumbar drain would be needed.
Well, a drain can be left in for several days, and longer, but this has to be balanced with the risk of infection which increases, the longer a drain is left in.
We have routinely left a drain in for a week to 10 days, without a significant increase in the infection rate.
The patient needs to stay in the hospital, to monitor the wound for leakage, as well as keep the drain sterile.
The wound typically will heal within several days to become watertight, and after that, theoretically the lumbar drain can be removed, though the wound should continue to be monitored.