Hey Charlie,Charlie wrote:.... regarding the ligaments again I am not disputing the reports of people who claim to have been made worse from having their ligaments operated on and I sympathize with them. However what I am still yet to hear is a mechanical explanation of why cutting the ligaments would cause pelvic instability. I say that in a non confrontational manner. I too have had PT's tell me it would cause pelvic instability but when I have enquired further they can never give me a solid, logical, mechanical explanation of why it would do this.
I took your quote from another thread so we could have an intense
discussion about it in a new thread. I can't give you a mechanical explanation but I studied this subject extensively before I decided on surgery and I came to the conclusion that the sacrotuberous (ST) ligament could be important in pelvic stability. I can't prove it but neither can anyone prove that the ST ligament is not important so I opted to play it safe. I already had SI/stability problems before surgery so maybe I was a little more worried about this than some PNE'ers are.
The problem for PNE patients is you've got some ligaments compressing the nerve and in order to relieve the compression the ligaments may have to be severed. So you may have to go with the lesser of two evils -- or opt for one of the surgery approaches that tries to save or replace the ligament.
Vleeming, Lee, and Tigney seem to be the experts on this subject. Here is a collection of articles/links that may help to explain the biomechanics of the pelvis and why the ST ligament might be important to stability.
http://thelowback.com/how.htm
Eur Spine J. 1993 Oct;2(3):140-4.
A functional-anatomical approach to the spine-pelvis mechanism: interaction between the biceps femoris muscle and the sacrotuberous ligament.
van Wingerden JP, Vleeming A, Snijders CJ, Stoeckart R.
Department of Anatomy, Faculty of Medicine, Erasmus University, Rotterdam, The Netherlands.
Abstract
Summary. Sacroiliac joint dysfunction is often overlooked as a possible cause of low back pain. This is due to the use of reductionistic anatomical models. From a kinematic point of view, topographic anatomical models are generally inadequate since they categorize pelvis, lower vertebral column and legs as distinct entities. This functional-anatomical study focuses on the question whether anatomical connections between the biceps femoris muscle and the sacrotuberous ligament are kinematically useful. Forces applied to the tendon of the biceps femoris muscle, simulating biceps femoris muscle force, were shown to influence sacrotuberous ligament tension. Since sacrotuberous ligament tension influences sacroiliac joint kinematics, hamstring training could influence the sacroiliac joint and thus low back kinematics. The clinical implications with respect to 'short' hamstrings, pelvic instability and walking are discussed.
PMID: 20058466 [PubMed - indexed for MEDLINE]
http://www.ncbi.nlm.nih.gov/pubmed/8852309
Joint Bone Spine. 2006 Jan;73(1):17-23.
Provocative sacroiliac joint maneuvers and sacroiliac joint block are unreliable for diagnosing sacroiliac joint pain.
Berthelot JM, Labat JJ, Le Goff B, Gouin F, Maugars Y.
Rheumatology Department and Orthopedics Department, Osteoarticular Pole, Hôtel Dieu Hospital, Nantes Teaching Hospitals, France. jeanmarie.berthelot@chu-nantes.fr
Comment in:
• Joint Bone Spine. 2007 May;74(3):306-7; author reply 307-8.
Abstract
Mapping studies of pain elicited by injections into the sacroiliac joints (SIJs) suggest that sacroiliac joint syndrome (SIJS) may manifest as low back pain, sciatica, or trochanteric pain. Neither patient-reported symptoms nor provocative SIJ maneuvers are sensitive or specific for SIJS when SIJ block is used as the diagnostic gold standard. This has led to increasing diagnostic use of SIJ block, a procedure in which an anesthetic is injected into the joint under arthrographic guidance. However, several arguments cast doubt on the validity of SIJ block as a diagnostic gold standard. Thus, the effects of two consecutive blocks are identical in only 60% of cases, and the anesthetic diffuses out of the joint in 61% of cases, often coming into contact with the sheaths of the adjacent nerve trunks or roots, including the lumbosacral trunk (which may contribute to pain in the groin or thigh) and the L5 and S1 nerve roots. These data partly explain the limited specificity of SIJ block for the diagnosis of SIJS and the discordance between the pain elicited by the arthrography injection and the response to the block. The limitations of provocative maneuvers and SIJ blocks may stem in part from a contribution of extraarticular ligaments to the genesis of pain believed to originate within the SIJs. These ligaments include the expansion of the iliolumbar ligaments, the dorsal and ventral sacroiliac ligaments, the sacrospinous ligaments, and the sacrotuberous ligaments (sacroiliac joint lato-sensu). They play a role in locking or in allowing motion of the SIJs. Glucocorticoids may diffuse better than anesthetics within these ligaments. Furthermore, joint fusion may result in ligament unloading.
PMID: 16461204 [PubMed - indexed for MEDLINE]
Spine (Phila Pa 1976). 1996 Mar 1;21(5):556-62.
The function of the long dorsal sacroiliac ligament: its implication for understanding low back pain.
Vleeming A, Pool-Goudzwaard AL, Hammudoghlu D, Stoeckart R, Snijders CJ, Mens JM.
Department of Anatomy, Erasmus University Rotterdam, Netherlands.
Abstract
STUDY DESIGN: In embalmed human bodies the tension of the long dorsal sacroiliac ligament was measured during incremental loading of anatomical structures that are biomechanically relevant.
OBJECTIVES: To assess the function of the long dorsal sacroiliac ligament.
SUMMARY OF BACKGROUND DATA: In many patients with aspecific low back pain or peripartum pelvic pain, pain is experienced in the region in which the long dorsal sacroiliac ligament is located. It is not well known that the ligament can be easily palpated in the area directly caudal to the posterior superior iliac spine. Data on the functional and clinical importance of this ligament are lacking.
METHODS: A dissection study was performed on the sacral and lumbar regions. The tension of the long dorsal sacroiliac ligament (n = 12) was tested under loading. Tension was measured with a buckle transducer. Several structures, including the erector spinae muscle, the posterior layer of the thoracolumbar fascia, the sarcotuberous ligament, and the sacrum, were incrementally loaded (with forces of 0-50 newtons). The sacrum was loaded in two directions, causing nutation (ventral rotation of the sacrum relative to the iliac bones) and counternutation (the reverse).
RESULTS: Forced nutation in the sacroiliac joints diminished the tension and forced counternutation increased the tension. Tension in the long dorsal sacroiliac ligament increased during loading of the ipsilateral sacrotuberous ligament and erector spinae muscle. The tension decreased during traction to the gluteus maximus muscle. Tension also decreased during traction to the ipsilateral and contralateral posterior layer of the thoracolumbar fascia in a direction simulating contraction of the latissimus dorsi muscle.
CONCLUSIONS: The long dorsal sacroiliac ligament has close anatomical relations with the erector spinae muscle, the posterior layer of the thoracolumbar fascia, and a specific part of the sacrotuberous ligament (tuberoiliac ligament). Functionally, it is an important link between legs, spine, and arms. The ligament is tensed when the sacroiliac joints are counternutated and slackened when nutated. The reverse holds for the sacrotuberous ligament. Slackening of the long dorsal sacroiliac ligament can be counterbalanced by both the sacrotuberous ligament and the erector muscle. Pain localized within the boundaries of the long ligament could indicate among other things a spinal condition with sustained counternutation of the sacroiliac joints. In diagnosing patients with aspecific low back pain or peripartum pelvic pain, the long dorsal sacroiliac ligament should not be neglected. Even in cases of arthrodesis of the sacroiliac joints, tension in the long ligament can still be altered by different structures.
PMID: 8852309 [PubMed - indexed for MEDLINE]
