Nerve blocks: differentiating between PN and PNE ?

[aussie_surfer]

Hi all.

I have read online that one of the criteria for having pudendal nerve entrapment (PNE) is a positive response to a nerve block.

But can I please ask, wouldn’t a simply inflamed or injured pudendal nerve (not necessarily entrapped), also respond positively to a nerve block?

Thanks so much

[April]

Hi Aussie,

Yes, it would. The nerve block is designed to ensure that it is the *pudendal* nerve and not another nerve (or another part of the pelvis) creating the pain. It doesn't help to differentiate between pn and pne.

April

[Violet M]

Right, it's not an exact science but the article I posted here helps to explain it: viewtopic.php?t=11731

Basically, a positive response to a nerve block confirms the pudendal nerve but also, you would probably not want to try surgery unless you responded positively to a nerve block because as this study says, you are not nearly as likely to have a successful surgery. Hope that makes sense.

Violet

[aussie_surfer]

Thank you so much Violet, for your very valuable insight, as always.

So I am wondering, why a positive pudendal nerve block, is an effective predictor of the success of surgery ?

Apart from identifying positively pudendal nerve involvement, do you think there is any other reason why it is an effective predictor of the success of surgery?

Many thanks

[Violet M]

I think a negative nerve block could be a predictor of an unsuccessful surgery. I think a positive nerve block could be a predictor of a successful surgery IF it's accompanied by the other essential Nantes criteria plus some complementary Nantes criteria. But that's just my assessment based on the peer reviewed literature.

As this article explains it, a pudendal nerve block does not prove there is an entrapment as opposed to just pudendal neuralgia.
https://www.ncbi.nlm.nih.gov/sites/books/NBK544272/
It states the following:
"Relief of pain occurs with a pudendal nerve block. This essential criterion is not specific, as any perineal disease other than entrapment can cause pain in the anatomic region of the pudendal nerve."

The article also states:
"A negative block also doesn't necessarily exclude the diagnosis of pudendal nerve entrapment if the block is placed incorrectly or performed too distally."

The positive nerve block is only ONE of the 5 essential Nantes criteria. There are also a bunch of complementary criteria. So if you meet the essential criteria and a bunch of the complementary criteria, including the positive nerve block, it points to a possible entrapment. If you meet some of the criteria but have a negative nerve block, it could mean the pudendal nerve isn't the problem, or the nerve block was placed incorrectly.

I think the main take-away from this is that if you have a negative nerve block, you would want to think twice about having pudendal nerve decompression surgery, but if you really think you have an entrapment based on meeting the other criteria, you might want to try another nerve block and be sure it is image guided before proceeding with surgery but that would be based on what your doctor recommends. Prof. Robert recommended 3 nerve blocks before surgery -- two at the ischial spine and one in Alcock's canal. That was back when they were using steroids though, so part of his rationale appears to have been partly linked to whether the steroids might take down the inflammation enough to heal the nerve so you could avoid surgery. https://www.pudendalhope.info/wp-conten ... Robert.pdf
The new guidelines from major organizations are showing that there is no evidence for steroids in pudendal nerve blocks. https://pubmed.ncbi.nlm.nih.gov/39019502/
There might be some rationale for trying an anesthetic diagnostic nerve block (no steroids) at the ischial spine and in Alcock's canal to see if one of those sites would elicit a positive response, if your doctor thinks it's a good idea.

Violet

[aussie_surfer]

Thanks so much Violet. I wonder why they stopped using steroids? It seems that a steroid would perhaps settle nerve inflammation generally?

[Violet M]

I don't know, I only have the abstract of the article https://pubmed.ncbi.nlm.nih.gov/39019502/
but maybe it would say if you can gain access to the entire article.
There are probably still practitioners who use steroids in PN blocks. I don't know that everyone has abandoned them.
From my own experience, steroid nerve blocks provided no long-term relief, and I know people who have gotten permanently worse from steroid nerve blocks. On this forum, we rarely, if ever, hear of people getting long-term relief from them.

Violet

[aussie_surfer]

Thanks so much Violet for all of your support of us. Your insights are so valuable, and very much appreciated.