Can L5 root nerve cause significant gluteal atrophy?

I have a question for any physiotherapists out there who can spare the time ......

Is it possible to have significant (visibly sagging plus pain & weakness etc) unilateral glute max wasting from an L5 root nerve problem?

Or would the L5 nerve only effect the glute medius? (my glute med & TFL also happen to be painful & weak)

I am looking to find out if this is an L5 or S1 root nerve problem or maybe both.

Any info on lumbar sacral problems relating to these symptoms would be much appreciated.

The Gluteus Maximus is supplied by L4, L5, & S! segments and Gluteus medius and minimus are supplied by L4, L5, S1 & S2. so while there can be some weakness usually there isn't really marked wasting as the muscles are supplied by more than one segment. this is if the problem is at the spinal nerve, of course.

Thanks for your response gcoe.

What I am trying to establish is if my L5 root nerve alone could be the only underlying cause of the severe wasting of the right hip girdle muscles. Or should I be considering that there might be some other structure also contributing to this issue, and if so what?

We assume at the moment that the L5 root nerve does have some significant involvement because I currently have the following to go on as diagnostics:

- L5 root referral pattern from buttocks down leg to foot.
- Weakness and marked atrophy in glutes as mentioned.
- Noticeable pain relief 3 days after L5 root block.
- known degenerative joint at L4/5 disc facets etc.
- My right lower leg is also feeling weak. (not sure of this is the knock on effect of hardly being able to walk on it for months).

I do have a great physiotherapist who I am working with at the moment but he has not seen anything get this severe. So I have posted on this forum in case anyone had experience of such a severe amount of glute wasting from nerve pain over a period of around 4 months.

Here's a bit more background info:
The severe pain episode started 6 months ago. Prior to this I was active and strong from daily core exercise routine, I had endurance and could easily steep hike for hours, went horse riding a couple of times a week. No other health issues. My low lumbar spine has an established 2 year old L5/S1 instrumental fusion. There was chronic joint pain at L4/5 facet due to degenerative disc but this was managed with analgesics and exercise. Pelvis, hips, spine fusion etc all checked out fine on X-Ray. MRI for L4/5 disc all OK.

gcoe, I am not sure what you mean by "segments". Do you mean vertebrae?

Many thanks

By segments I refer to the the spinal cord segment that the spinal nerve that is damaged. The wasting is not due to pain; it is due to damage to the nerves resulting in either a loss of nerve cell function or nerve cell death. If you are having that amount of weakness something seriously has happened to your spinal nerve(s) - most likely L5 and possibly also S1.

Since you have had a previous fusion I presume you had severe back pain with nerve damage back then? Was it on the same side?

While it is good that the xray shows the spinal fusion is ok one would have to suspect something has gone wrong. Something in there is most likely severely pressing on the spinal nerve(s). Alternatively segments above or below a fusion do have a tendency to have problems as they now take a lot more shearing forces and due to abrupt change from normal movement in the other spinal segments and the sudden loss of movement. However this usually takes a several years to develop if it is going to.

One question: did the weakness develop quickly after the nerve root block or was it there before?

I don't know how much interaction you have had with your surgeon in recent weeks but I think it is important that he knows you are having severe recent nerve damage.

Thanks gcoe,

It's good info for me regarding the nerve cell "function" as apposed to just thinking about the pain pattern. I will ask my surgeon to explain this aspect of my condition next week.

I want to understand how the glutes became so wasted as it certainly wasn't from disuse before this episode! I need to establish that there is no barrier to me being able to rehabilitate this muscle function. There is currently "life" in the glutes, I can contract them now, but I am in a lot of pain in my low lumbar/pelvis from the effects of this latest episode.

The fusion was done 2 years ago due to back pain and instability (hardly any disc left and very slight retrolisthesis) I also had intermittent Right sided nerve pain.

gcoe, from my experience I do agree with what you say about the rate (if any) of adjacent segment degeneration above a fusion. Even tho I am in some trouble now It has to be understood that my L4/5 disc didn't degenerate purely in the 2 years it has been sat above a fusion. It was not in perfect shape before the fusion. It had needed a microdiscectomy for a left sided prolapse 2 years before the fusion to cure L5 nerve pain, this discectomy was 100% successful and I have never had any pain on the left side since. We did "top off" the fusion with an interspinous spacer but I had trouble with the spacer 4 months after op and had to have it removed (unlucky!). Even after all that I was fine doing physio exercises, hill hiking, horse riding etc. for most of last year.

The current pain episode I am dealing with started 7 months ago, I had a lot of pain across the level of my fusion at L5/S1, plus at L4/5, especially on the right where I know the facet joint usually hurts, plus some right leg pain (at that time leg pain was not quite as marked as it is now) plus pain running distal from fusion down to lower sacrum. This is why I had the X-ray taken in December. Since then the nerve pain, leg weakness, glute atrophy etc. developed. All on the Right.

I had an MRI more recently to check for nerve impingement etc, nothing obvious from this. (bare in mind the MRI is of me laid flat and motionless and may have limited value) So, after the MRI my surgeon tried out the L5 root block. The nerve root block was done recently as a diagnostic and I did get some pain relief 3 days after block which continued to help over the next few weeks. It also seemed to help with my general muscle function as prior to the block I had an awkward painful gait with my right leg rotated laterally. After the root block my leg straightened up a bit and made walking easier, maybe some muscle spasm eased at the time? or just a coincidence? I'm just guessing

Over the last few weeks I thought it had improved enough after the root block to be able to rehabilitate with physio, but over the last few days the right sided symptoms of nerve pain and leg weakness have returned plus the pain in lower lumbar has increased.

This brings us up to date.

If anyone can suggest relevant questions I should ask my surgeon and physiotherapist next week it would be much appreciated.


Sorry it's a bit of a long message but the more you probe the more history comes out!