Thanks for reading the 20th edition of my sciatica newsletter. This newsletter tracks my research into all things lumbar radicular pain!
Hello for the first time in three weeks! I've had my head down writing the book, which is going very well, but that means I haven't taken time out to write a newsletter recently.
Today I want to talk a bit about diagnosis, and what it's for.
Let's say your patient has pain down the back of their leg. From talking to them and seeing them move, you are fairly sure it's coming from their low back.
Sometimes it’s just obviously a painful radiculopathy. It's just like the textbook told you it would be: your patient's pain started a day or two after she put her back out; now it shoots right down the expected dermatome into the outside aspect of her foot, where she has a patch of numbness. Your physical exam is just to rule out other stuff. We can go ahead and write "painful radiculopathy" in the provisional diagnosis box.
Now, let's say the picture is more vague. Your patient can't really remember how the pain started; it travels down into her leg but not in any particular dermatome, and she might have a patch of numbness but she's not sure, it's more like it feels funny than numb. If you want to make a diagnosis of radicular pain (or referred pain), you are going to have to spend some time digging. You only have half an hour or so, and other things to do in that time. Is it worth it? Why not just write "low back related leg pain" in the box? Let's say you spend fifteen minutes masterfully diagnosing a painful radiculopathy: so what?
I am a big fan of this question. The "so what?" test. It stops clinicians who like to noodle around, navel gaze and generally over-think things (like me) from disappearing too far up between their glutei. There's no point in making a diagnosis for its own sake. The diagnosis is the means to an end, not the end in itself.
We need to be clear about what our reason is for making a diagnosis more specific than "low back related leg pain". The way I see it, these are the possible reasons:
Your patient is struggling enough to consider surgery. But surgeons don't operate on "low back related leg pain", they operate on radicular pain. (Sure, the surgeon will make their own diagnosis, but to begin to discuss it with your patient and to make the referral, you need to make one, too).
Your patient is struggling enough to consider taking medications with non-trivial side effects. But doctors don't prescribe medication for "low back related leg pain", they prescribe gabapentin for neuropathic leg pain, or oral steroids for radiculitis.
Your patient is struggling enough to consider an epidural injection. But doctors don't inject people with "low back related leg pain", they inject people with radicular pain.
If your patient has radicular leg pain, you think that needs closer monitoring than referred leg pain, so you will ask to see her again sooner for another neuro exam, and maybe take some other measures.
Your patient says she wants you to find out as much as you can about what is happening in her back and tell her, or words to that effect.
Your patient is struggling to make sense of her symptoms. She tells you they get worse at certain times but she can't work out why, that she has unusual sensations that are not best described as pain, and that the pain she does have feels unusual too. If you can find out that her pain is radicular, then that diagnosis gives you both a framework for beginning to understand what is going on.
If your patient’s pain is radicular then you would ask her to do certain exercises, like neurodynamic techniques (this is debateable, but that’s a topic for another time).
So these are my examples of when a specific provisional diagnosis of radicular pain would pass the So What Test. (I think that fairly often, it wouldn’t.) I'm really curious to know if you would add anything to that list. What are some other good, practical reasons to make a specific diagnosis for people with low back related leg pain?
Other bits and bobs
"Lumbar disc extrusions reduce faster than bulging discs due to an active role of macrophages in sciatica" - a paper from Professor Ostelo, who I interviewed in the last podcast
Everything is heritable, and that includes the state of your spine! "Despite extraordinary discordance between twin siblings in occupational and leisure time, physical loading [had] surprisingly little effect on disc degeneration."
Foetal discs compared to old age discs. Foetal discs are almost 50% endplate.
Donella Meadows: "Remember, always, that everything you know, and everything everyone knows, is only a model. Invite others to challenge your assumptions and add their own. Instead of becoming a champion for one possible explanation, or hypothesis or model, collect as many as possible".
Book talk
As I said, the book is going pretty well. I've really picked up the pace with writing in the last few weeks. I'm making a real effort to make every sentence of every paragraph as clear, direct and easy to read as possible. I want everything in it to feel edifying, surprising and fresh to the reader. Like everyone, I've been conditioned for a lifetime to write in a complicated but predictable way in order to get a good mark on an exam. But writing to help people do something in the real world is totally different and I've had to unlearn a lot of bad habits.
Because I am in control, I can cut out all the stuff that so often makes academic writing and journal papers bad to read. For example, I'm not spending ages talking through the finer points of different debates and philosophies and points of view. I'm letting all that inform what I say, but I'm not putting it on the reader to work through. I'm working through it myself and telling them plainly what I think.
I also don't have to stick to conventions like "subjective assessment", "objective assessment" and so on. I'm assuming my reader already knows what they are and doesn't need me to walk them through it. Instead, they want me to help them answer specific questions about the assessment that give them trouble. So that's how my "assessment" section is organised: how to answer specific questions.
I also realised I don't need to provide boring illustrations that someone could just get off google images. The usual anatomy picture with a big red circle around the bit that hurts. Instead, I'm making illustrations that demonstrate concepts to help what I'm saying "click" in the reader's mind. I'm really looking forward to sharing them with you!
Cautiously, I'm confident I will meet my February 1st deadline! I’m really excited about how it’s shaping up.
Kanban update:
Til next time,
Tom