Thread of threads on sciatica.

1) Differential diagnosis

https://twitter.com/thomas_jesson/status/1721968329676497109

2) A gruesome study...

https://twitter.com/thomas_jesson/status/1621541752506093568

Thread on differential diagnosis of lumbar radicular pain, aka

"I think my patient has sciatica, could it be anything else?" 🧵 Firstly, this isn't meant to be a 'do it like this' tweetorial, but it's how I think of this stuff and the goal is to help you think about it, too.

Disclaimer over.

I just spoke to a friend who is going to start a newsletter soon (exciting!) and it got me thinking about writing advice.

I'm don't claim to be a great writer, but here is some of the advice I try to keep in mind and that has contributed to the small successes that I have had: The most important thing is to try to shake out the habit of writing school essays that explain class material to an imaginary teacher. This is the number one thing that kills a piece stone dead.

Instead, remember you are writing something *of value* for *an actual person*.

If you want to start a fight in a bar full of physios, mention piriformis syndrome.

'Piriformis syndrome' is practically a household name now, and yet plenty of clinicians will tell you it doesn't even exist.

What's going on?
🧵 Well, the first thing to know is it's changed it's name!

It's called 'deep gluteal syndrome' now...

A few notes on a "loss of saddle sensation", one of the five red flags for cauda equina syndrome... 🧵 Like the other CES sx (bladder, bowel & sexual dysfunction), a loss of saddle sensation is caused by compression of the lower sacral nerves.

They travel right down the middle of the lumbar cistern, so only big, central disc herniations - which are very rare - can squash them

Why would sciatica take a couple of weeks to kick in?

So often our patients describe a 'tweak', shortly followed by back pain... but their radicular pain doesn't get going until later.

Here's what might be going on... 🧵 First explanation: It could be that a disc herniation is slowly developing.

We think of disc herniations as sudden events that are over in a short time: the nucleus sort of splurges or, erm, ejaculates out, and then it sits there and causes trouble.

Can you trust this man?

There's a dermatome chart in every MSK textbook, but the reality is not so clear cut... 🧵 Firstly, although it's claimed that sciatica (lumbar radicular pain) follows a dermatomal pattern, this doesn't seem to be the case.

"How long does sciatica last?"

If you ask the internet, even reputable sources will tell you "4 to 6 weeks".

If you ask the evidence, the answer is a bit different... Here's what we know🧵 1) For people with very acute sciatica, there's a rough rule of thirds. Over the next couple of weeks, they have:

- About a 1 in 3 chance of greatly improving
- About a 1 in 3 chance of improving a fair amount
- About a 1 in 3 chance of staying the same or getting worse

Cauda equina syndrome is confusing! But if you get to know the condition beyond the red flags, things do become clearer.

With that in mind, here are 10 papers to start with... 📚 1/ First, you'll want to get a handle on what CES actually is. For that, try this paper by Fraser and colleagues. It shows how the current definition of CES has been worked out over time, into that list of red flags we all now know so well
drive.google.com/file/d/1hLkQxL…

For me, bladder dysfunction was always the most confusing symptom of cauda equina syndrome.

So here's what I wish I'd understood earlier... 🧵 All the anatomy you really need to know:

- The bladder uses the S2-4 nerve roots roots to send "I'm full!" messages to the brain and spinal cord.
- And the brain & spinal cord use those same roots to send "Okay, empty out" messages back the other way.

But...

Here's an unforgettable study on sciatica and disc herniations, firmly in the category of "you couldn't do that these days".

The study was performed in Leeds in 1958... 🧵 At the time, people knew that disc herniations can cause sciatica.

But they didn’t really know how.

Most people thought that it was through compression. But the authors of this paper, Doctors Smyth and Wright, had a hunch that it wasn't quite that simple.

Disc herniations and sciatica. What do we actually know?

Here's my understanding of the evidence... 1) Asymptomatic disc herniations are common. Loads of you have them and don't know it! But...

New back to basics post defining commonly-confused terms:
- Referred pain
- Radicular pain
- Radiculopathy
- Sciatica
thecesbook.com/blogs/blog/wha… If you have time I also (even instead!) recommend reading the classic paper by Bogduk - drive.google.com/file/d/1KkjaKm…

Just got a message asking me for some reading on neuropathic pain, so here are a few papers I found useful and (just about) readable.

1) Nature Reviews neuropathic pain primer

drive.google.com/file/d/197Y0IF… 2) The role of the immune system in the generation of neuropathic pain by Calvo and colleagues.

drive.google.com/file/d/1g1wfcV…

A few of the improved drawings for the republication of Sciatica Book 1 👷‍♂️🚧 More...

I just sent a reader some papers on surgery for sciatica, so I thought I might as well share them here too...

(I'm still learning about this topic and have no strong opinions, always interested to hear input) 1/ 2/ The Maine Lumbar Spine Study from 1996 is one of the classic studies in this area.

"Surgically treated patients with sciatica reported substantially greater improvement at one-year followup" drive.google.com/file/d/1Db9xVz…

Sad to learn of the death of Hillary Mantel. As well as writing perhaps the best novel written in many decades, she also wrote better than anyone about the experience of pain and illness.

E.g., nothing I;ve read better captures being hospitalised than: lrb.co.uk/the-paper/v32/… Here she is on pain: "Pain cannot easily be divided from the emotions surrounding it. Apprehension sharpens it, hopelessness intensifies it, loneliness protracts it by making hours seem like days." Perfect.

abetternhs.files.wordpress.com/2013/09/mantel…

More evidence that the size of a disc herniation has little effect on the intensity of radicular pain!

Here's a thread on how I interpret this common finding... and how I think it should *not* be interpreted.

(As ever, I'm keen to hear what I've missed.)

https://twitter.com/PhysioMeScience/status/1566830927069777920

Firstly, there are a few reasons why we wouldn't actually expect herniation size to correlate with pain...

Great thread. I think I will make a thread of my own here with some notes on spinal metastatic cancer. 1/

https://twitter.com/ClementsCharl96/status/1551949649753395203

This is not intended to be a summary (Charlie's thread does that! Also read the NICE guidelines...)

But just stuff I've found interesting in my reading. Very keen for people to tell me where I'm wrong, what I'm missing etc. Not an expert. 2/

I think this week's newsletter would lend itself to a good old fashioned thread... so here's a visual tour of the lumbar nerve roots! Let’s start at the top. The spinal cord ends at about the L1 vertebral level (higher than most people think!). The cord tapers to terminate at the conus medullaris:

Some random thoughts on CATEGORIES. (warning - unformed and uninformed) Categories "carve nature at its joints". Nature is not pre-carved.