Nantes Study on the ST and SS ligaments

[Charlie]

There has been a lot of discussion on the ligaments recently. I have posted below the Nantes study on the ST and SS ligaments published in 2008. I think this is relevant information. There are counter arguments but people can form their own judgement on it.

Are sacrospinal and sacrotuberal ligaments involved in sacro-iliac joint stability?
[Article in French]

Philippeau JM, Hamel O, Pecot J, Robert R; Laboratoire d'Anatomie de Nantes.

Service de Chirurgie Orthopédique et Traumatologique, CHU de Nantes, Nantes, France. jmphilippeau@hotmail.com
Abstract
OBJECTIVES: Surgery of pudendal nerve entrapment needs the section of both sacrospinal and sacrotuberal ligaments. We asked about the potential side effect of such a section especially on sacro-iliac joint stability.

MATERIAL AND METHODS: We performed a cadaveric anatomical and biomechanical study concerning six sacro-iliac joints. Joints were tested on a plateform, and results were analysed with a logiciel(Medai)(R), both especially developed for, before and after sacrospinal and sacrotuberal section.

RESULTS: The computered analysis of our results proved that sacro-iliac joint has a significant range of motion, specially in youngs. Results obtained confirmed that there is no statistical difference (p<0.05) between the mobility of sacro-iliac joint with or without sacrospinal and sacrotuberal ligaments.

CONCLUSION: This original experimental biomechanical study is the first able to test the influence or sacrospinal and sacrotuberal section on sacro-iliac joint stability. The section of those ligaments has no significant experimental consequence on the sacro-iliac joint stability and cannot create a postoperative instability.

PMID: 18534888 [PubMed - indexed for MEDLINE]

http://www.ncbi.nlm.nih.gov/pubmed?term=18534888

[JeanieC]

Charlie,

Thanks for posting this study of the SS and ST ligaments. It is good to know that there is ongoing scientific research of their effect on sacroiliac joint stability.

[Violet M]

. There are counter arguments but people can form their own judgement on it.

Thanks Charlie. I was wondering - what do you think the counter-arguments are?

[Charlie]

Hi Violet

I think the counter argument would be that the study was performed on cadavers and of course cadavers cannot report pain.

What I would say to that is that the study still demonstrated that instability was not caused by the severing of the ligaments. Perhaps severing the ligaments does cause pain but the study would demonstrate that this pain is not a result of instability.

Another counter argument would be that the study was only performed on six sacro illiac joints. That is a small sample.

Also what I am discovering is that everyones bodies can be slightly different. Before I became ill with this problem I naively assumed that structurally we are all the same. I almost thought that you could learn about the structure of the body as a mechanic would learn about an engine, everyone is the same. Of course by and large we are the same but as I have read more I realize that everyones bodies are very slightly different. Could it be then that some people's sacro illiac joints do become unstable after the severing of the ligaments while others don't? I don't know.

Another argument may be that the study is performed by a group with a vested interest in showing it does not cause instability. I would not agree with that argument though. I think the Nantes team have been very open about sharing their methods. They were the pioneers of PNE.

[Violet M]

Thanks for the reply Charlie. I agree with you about the variations in anatomy. When my son took cadaver lab he was surprised at the variations in anatomy between each person. Gives you a new admiration for the surgeons who sort through all of the nerves, vessels, etc. as they perform surgery.

There is another study that concluded certain ligaments were not important, can't remember what study it was or what ligaments were discussed but in the conclusion they pointed out that it depended on how the cadavers were loaded. I'm not sure how you would test a cadaver standing up as a normal human would.

[HerMajesty]

It's impossible to judge the quality a study on the basis of an abstract alone; but what concerns me the most about this one is the statement, "The computered analysis of our results proved that sacro-iliac joint has a significant range of motion".
Of course they do not state what they consider "significant" range of motion; but numerous other sources establish that the range of motion in the S-I is very limited, generally 2-3 mm.
As much of restricted S-I motion is due to numerous short ligaments in and around the joint capsule, the fact that they found "significant range of motion" leads me to wonder about the general condition of the cadavers and whether the ligamentous tissue was already degraded.

[nyt]

It is an interesting first study to attempt to understand the importance of these two ligaments. However, they can not take into account the effects of weight bearing, the stress of standing, the effects of laying on your back and any normal every day activities. I also agree with HerMajesty in that any other study I have read the belief is there is minimal movement of the SI joint.

[Karyn]

It is an interesting first study to attempt to understand the importance of these two ligaments. However, they can not take into account the effects of weight bearing, the stress of standing, the effects of laying on your back and any normal every day activities. I also agree with HerMajesty in that any other study I have read the belief is there is minimal movement of the SI joint.

I also agree. I've been informed by (2) PT's and a MD of Physical Medicine that there is minimal movement of the SIJ.
Still very interesting, though!

[Charlie]

It is an interesting first study to attempt to understand the importance of these two ligaments. However, they can not take into account the effects of weight bearing, the stress of standing, the effects of laying on your back and any normal every day activities.

I see the point your making here nyt and recognize the limitations of doing it on cadevers but was n't that the point of the study. To try and recreate the normal forces on the pelvis to see if instabilty was created when the ligaments were absent. That may not be possible to do but I think that is what they were trying to do.

[AliPasha1]

Excellent points by Karyn,NyT,Violet and ofcourse HerMajesty.The biggest problem is it is coming from the Nantes team which has openly denied any forms of Pelvic instability like SIJD,tailbone pain Priformis muscle after they sever the ligaments especially the Sacrotuberous ligament.Secondly, if young kids need those ligaments then why not older people because their cells,tissues,bones,ligaments are all wearing off with age.It makes no sense.

The Nantes team denies that none of their patients ever developed any form of Pelvic Instability(I coul be wrong that they don't admit it) .And then the question arises why work on Six dead Cadevars when you have results from 2300 surgical cases .
Charlie made a good point that the Cadavers can't experience pain hence the research paper is pointless.However,if we want to discuss biomechanics of ligaments and tendons the following paper discusses it in far more detail.

http://www.engin.umich.edu/class/bme456 ... ligten.htm

An above all ,how does the Nantes team explain the following if none of their patients never developed any Pelvic issues like SIJD,Piriformis Muscle syndrome,etc.

by PierreQC » Tue Feb 08, 2011 12:56 am

Yes absolutely, in my case i would say that it does matter if you want to do sports after your surgery.

Look at the situation and use your logic. Try to figure out the pelvis without these ligaments.
Any shocks (like walking downhill) or rotation will eventually put too much stress on the remaining sacroilliac ligaments resulting in an anterior/posterior rotation of the pelvis. Living with a lax sacroilliac ligament can be as problematic as PNE. Your pain is in the anus and back of the buttock, lower back and feets instead of more forward and deep in the perineum. Exchanging one problem for another is not better.

You know, things that should logicaly turn bad, usually do.

Again, use your logic. If the nerve is entraped between two ligaments why do we need to cut more than one ligament to transpose it ??? How could the sacrotuberous harm the transposed nerve if it is on the other side of the sacrospinous ?? Pr. Robert tried some surgery without sacrificing the ST and stopped apparently. I tough it would be the norm. Is the outcome of the surgery better when it open up, slack, the pelvis like that i don't know ?? I hope it is not just a question of surgery time. In 2004 when I had surgery, Pr. Robert could still say that these ligaments had no purpose but after a decade of patients history it is clear that many people develop SI disfunction.

If you go to have surgery thinking that these doctors are expert in everything that concern pelvic pain, then you will be disapointed. They will do a few specific neurologic tests, a few manual exams but as other specialist doctors, they are compartimented and they will not realy try to find the reasons of the origin of your pain.

You are on your own.

So use logic. And shop your health care as if you would do it for the most important person in your life if it is not you.

P.S.: First post in 4 years. 60% better form PNE but SI pain increasing and causing me more and more trouble. Prolotherapy helped a bit but anyway none of the remaining ligmanets are in a position to replace the lost one even if they would be much stronger.

P.P.S.: I realized that the post was 7 pages long after I wrote this message. I had read only the first one. Everything has already been said.PierreQC

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Private message Kind Regards,
Ali