(This is the second in an occasional series on the weird things that can go wrong with your brain and what we do about them at Sunnydale General.)
So you've developed a leak somewhere in your skull, and cerebrospinal fluid (CSF) is dripping out your nose, or your ear, or under your skin. This is not good. In addition to being a serious risk for meningitis, it's a pain in the ass--you're getting headaches and feeling generally under the weather.
Or maybe you've developed hydrocephalus because your CSF isn't circulating properly. Maybe you've got normal pressure hydrocephalus (NPH) because you're getting older, and it's one of those things that sometimes happens. Maybe you've had brain surgery in the past and the circulation problem stems from that.
In any event, your doctor wants you to have a lumbar drain.
What in Hell is A Lumbar Drain, Anyhow?
A lumbar drain is a tiny tube that goes into the small of your back and allows CSF to drain out. The rate and amount of drainage is controlled by a nurse, in concert with a pressure burette (a little tube with a float in it) or a burette with a stopcock that can be turned manually. It's a temporary measure, used to reduce fluid pressure long enough for a leak to heal or for us to make sure that a more permanent solution, like a ventriculoperitoneal shunt, will actually work.
So How Will Draining Fluid Out of My Back Help My Brain?
Remember those cartoons where Wiley E. Coyote is chasing the Roadrunner through the desert, and the temperature climbs so high that the mercury bursts through the top of the thermometer? Imagine your brain and spine as that thermometer. If Wiley were to drill an itty-bitty hole at the bottom of the thermometer, enough mercury would leak out that there wouldn't be enough left to bust through the glass at the top. There would still be enough to do the job of showing the temperature; it just wouldn't be under enough pressure to do actual harm to the glass.
That, in a clumsy nutshell, is how lumbar drains work. We pull *just enough* CSF off of your brain to bring the pressure down. In the case of a CSF leak, this allows bone and soft tissue to heal by taking the constant outward pressure off of it. In the case of NPH, it allows your brain to relax, because it's not constantly getting squished up against the inside of your skull.
The big difference between Wiley's thermometer and your lumbar drain is that you will not, at any point in the process, have an anvil marked ACME dropped on you.
Great. How Do You Put This Thing In?
I'm so glad you asked. Putting in a lumbar drain is a bedside procedure. Except in rare cases when we have to do it under X-ray, it'll be done in your room. Setting up for the insertion takes fifteen minutes or so; putting in it takes less than five.
The doctor will use a fairly sizeable needle to puncture the skin of your back in a particular place where your vertebrae are separated. Then she'll run a very thin tube (the drain) with an even thinner wire in it (to give it some stiffness) up your back, inside your spinal column but outside your spinal cord itself. Then the wire comes out, and the drain gets connected to a closed burette and a drainage bag. The whole shootin' match is sterile. The drain will be stitched in to lessen the possibility of it being pulled out, and the area where it enters your back will be covered with a big sterile dressing.
This sounds horrible, but it's not that bad, according to the hundreds of patients I've had who've had it done. Your skin is thoroughly numbed before the big needle hits it, and I have really, really good drugs for you besides. The two most uncomfortable parts of the whole procedure are getting the lidocaine (skin-numbing medicine) injected into your back--that burns like a sonofoabitch--and having the drain run up your back. Occasionally, the movement of the drain tubing causes sharp, sciatica-like pains down one or both legs. Luckily, this is momentary and does not happen more than once or twice.
Now I Have This Tube Coming Out Of My Back. What Next?
Next comes the draining. Every four to six hours you'll have roughly a tablespoon of fluid drained out of your back. Ideally, that should take a half hour to an hour. You'll have to lie down horizontally during the draining and for a half hour to an hour afterwards to avoid getting a headache.
Aside from the times you're draining out fluid, you can do pretty much whatever you like except shower. Showering could mess up the dressing and cause an infection. You can walk, eat, talk on the phone, do a restrained and gentle Charleston (as long as you keep the drain with you), whatever. The drain will probably be hitched to an IV pole, which will limit your mobility a bit, but we sure don't want you just staying in bed.
What Can Go Wrong?
Well, you could get an infection. That's the number-one risk of any procedure that breaks your skin. We try to keep the possibility of that down by being sterile during the insertion, and by not letting you shower or mess up the dressing afterwards.
You could get a headache from over-draining. That's fixable, though, with fluid and caffeine and pain medicine.
The drain could break off at the point where it enters your body (extremely rare; I've only seen it once), or the point where we attach it to the burette tubing (much more common; happens maybe one in twenty times). If that occurs, all you have to do is call your nurse. He or she will handle it, along with the neuro doctor. It's not a big deal for you, and it doesn't mean you've done anything wrong or stupid--sometimes that little drain tube just stretches and snaps.
The consent you'll sign for the drain placement will talk about possible herniation of the brain or hemorrhage into the spinal cord, but I have never once seen or even heard of those things happening.
How Long Will I Have To Have This Thing In, and What Happens When It Comes Out?
You'll usually have the drain in less than a week. That reduces the risk of infection, and if we can't fix your leak in seven days of draining, you'll probably need surgery.
Once it's taken out, you'll have a sterile dressing placed over the spot where the drain went in, and you'll be told not to shower for another 24 hours. After that, you can go back to showering, parasailing, juggling chainsaws--whatever passes for normal activity for you.
Anything Else I Need To Know?
Well, lumbar drains are great for healing small CSF leaks, but sometimes they fail and you need a fat graft to block the leak. They're also great for reducing NPH, but sometimes they just plain don't work. As with any first- or second-line treatment, there's the possibility that you'll have to have something more extensive done to fix your problem.
Also, during the time that you have the drain in, your nurse will be taking samples of your CSF from the burette. You will not feel this. It's to make sure that you're not cooking some sort of infection up in your spine. You won't get antibiotics unless you do get an infection, which is very, very rare. (I'm trying to remember if I've ever had a patient get an infection from a lumbar drain, and I can't recall. I don't think so.)
*** *** ***
And that, friends and neighbors, is a quick guide to lumbar drains. Next up: fat grafts and VP shunts! Wahoo!
