SCIATICA: ETIOLOGY & THEORIES
1/1/2020
Theories of some common causes of Sciatica, with focus on Sacroiliac Joint (SIJ) biomechanics:
1/1/2020
Theories of some common causes of Sciatica, with focus on Sacroiliac Joint (SIJ) biomechanics:
@physioosteogram
“ILIOLUMBAR LIGAMENTS VS. SCIATIC NERVE ENTRAPMENT
The primary role of the iliolumbar ligaments (ILL) is to prevent excessive lumbar sidebending, but these ligaments can contribute to sciatic nerve (SN) entrapment… instagram.com/p/B6xZBomi6rr/…”
“ILIOLUMBAR LIGAMENTS VS. SCIATIC NERVE ENTRAPMENT
The primary role of the iliolumbar ligaments (ILL) is to prevent excessive lumbar sidebending, but these ligaments can contribute to sciatic nerve (SN) entrapment… instagram.com/p/B6xZBomi6rr/…”
(For lay readers: Sciatic nerve is major nerve that innervates leg and carries motor nerves that make leg work. Pain generated by impingement of this nerve is called “sciatica”. Sciatic nerve tracts just below sacroiliac joint as this nerve exits pelvis).
CANT is a word with the following DEFINITIONS:
NOUN: a slanted or tilted position
ADJECTIVE: oblique or slanting
VERB: to bevel, form an oblique surface, tilt, tip, to put in an oblique position
NOUN: a slanted or tilted position
ADJECTIVE: oblique or slanting
VERB: to bevel, form an oblique surface, tilt, tip, to put in an oblique position
IPSILATERAL = same side
CONTRALATERAL = opposite side
VERGE of a bone is the topmost contour
CONTRALATERAL = opposite side
VERGE of a bone is the topmost contour
COUNTER-NUTATION (CN) & NUTATION (N) are terms describing spacial relationship of two bones (Sacrum & Ilium) that comprise sacroiliac joint. During CN the superior sacral verge shifts posterior relative to Posterior Superior Iliac Spine (PSIS).
NUTATION: Superior sacral verge shifts anterior relative to PSIS. In that there is a virtual transverse axis of rotation through mid-SIJ, about which the two SIJ bones rotate, reader can deduce directional shifts of Ischial prominences during CN & N.
Within the discussions below, clinicians are informed how to evaluate patients for COUNTER-NUTATION & NUTATION, and how to monitor Sacral, Iliac, & Ischial prominence shifts.
Me: As I understand your theory @physioosteogram, the Iliolumbar Ligament (ILL) causes direct impingement of lower lumbar nerve roots; thereby arousing Sciatica. You also posit that a function of ILL is to prevent contralateral lumbar flexion.
It seems the idea that the Iliolumbar Ligament (ILL) impinges neural roots causing Sciatica is a theory put forth by @physioosteogram. I have not heard of this theory previously. Is there any supportive clinical data?
My own regard is that station of ILL is one whereby tissue plane of the ILL is more anterior medially (insertion on L-5) & more posterior laterally (insertion on iliac crest). Plane of ILL is not a true coronal plane, but cants posterior as it tracts from proximal to distal.
My regard is that the ILL tissue functions to oppose two bones that conjoin as the superior aspect of a sacroiliac joint (SIJ), i.e., the Posterior Superior Iliac Spine (PSIS) & superior aspect of the Sacrum bone, the Sacral verge.
The station of the ILL suggests that it functions to prevent counter-nutation of the SIJ. In persons with ILL injury, laxity, & loss of full tethering strength, direct palpation of the ILL arouses distinct pain. The exam is much easier in lean persons.
During palpation of the ILL, the clinician uses fingers to track posteriorly along the Iliac crest into the region of junction of Iliac crest with the lower lumbar spine. Palpation is made into this junction. This is a method of my own invention.
I regard that significant pain aroused by palpation of the ILL to be a valuable diagnostic sign, but one not previously reported in the medical literature. Not to say this sign proves the diagnosis; pain arousal merely supports diagnosis of ILL injury.
In people with suspected SIJ dysfunction (subluxation due to ligament injury) clinician can sit them on firm chair seat & place a 1” bolster (Gideon Bible perfect) under contralateral Ischial prominence; tilting upper body mass over & above suspected injured-SIJ.
This upper body mass burden causes subluxation (dysfunction) of a ligament-injured (lax) SIJ; shift of the SIJ into counter-nutation; whereby the Iliac crest cants slightly lateral & rotates anterior a few degrees.
Simultaneously, during counter-nutation, the ipsilateral Ischial prominence associated with the dysfunctional SIJ shifts posterior & slightly medial on the chair seat.
All of these shifts can be discerned in real time with sensitive touch in a lean & SIJ-injured women (usually a woman with soft tissue hypermobility; see below), but there should be a female attendant; palpation of Ischial prominences can seem odd to most women.
One way to palpate direction of Ischial shifts during counter-nutation is to have the women sit with her Ischial prominence on clinician’s upturned fingertips & as counter-nutation is evoked by the contralateral Ischial 1” bolster.
In a lean woman, direct bilateral palpation of Iliac crests, in real time as counter-nutation is evoked, enables comparisons & discernment of bone shifts occurring on side of the suspected SIJ dysfunction. In this way, clinicians learn bone shifts of counter-nutation.
The ligament injuries being reported herein are most commonly found in women, & in women who have been potentiated to ligament injury by a tissue variation called Hypermobility Spectrum Disorder (HSD).
My estimate is that about 15% of women have manifest hypermobility of their ligaments. It is estimated that 4% of women have Fibromyalgia & 1:500 have Ehlers-Danlos Syndrome (EDS).
Most women with Fibromyalgia (FM) have HSD; clinical studies have taught me this (study of FM in Proceedings of 10th Interdisciplinary World Congress on Low Back & Pelvic Pain, 10/2019, Antwerp; on line). I suspect that most women with EDS have HSD.
Most women with Fibromyalgia (FM) have HSD; clinical studies have taught me this (study of FM in Proceedings of 10th Interdisciplinary World Congress on Low Back & Pelvic Pain, 10/2019, Antwerp; on line).
I suspect that most women with EDS have HSD, but I have no data to support this.
To learn the clinical signs of hypermobility & diagnosis of HSD, clinicians need to study the “Beighton” & the “Brighton” “Criteria”; both on line.
Fibromyalgia & Ehlers-Danlos Syndrome (EDS) are, in my regard, consequences of HSD. Women with Fibromyalgia commonly develop the Fibromyalgia Syndrome from acute or chronic/repetitive biomechanical soft tissue injuries.
Women with Ehlers-Danlos Syndrome (EDS) develop symptoms merely from having significant cartilaginous variations of tissue laxity & from being exposed long-term to earth’s gravitational field; a chronic repetitive force of biomechanical stress (my theory).
In the library of my thread reader unrolls, I have additional essays about Fibromyalgia, HSD, & EDS.
Back to discussion of pelvic girdle disorders & Sciatica. Before & after counter-nutation is undertaken, note should be made of symmetry of the anterior tibial plateaus (ATP). They both should align symmetrically before the Ischial bolster is placed.
After the contralateral 1” bolster has been placed, the anterior Tibial plateau (ATP) ipsilateral to the injured ILL will shift posterior 0.5-3.0 cm relative to the contralateral ATP. One might call this a “functional shortening” of the ipsilateral femur.
Explanation for ATP asymmetry is that during counter-nutation the SIJ rotates a few degrees around a virtual transverse axis through the anatomical mid-region of the injured SIJ.
On right body side, rotation of the Ilium (relative to Sacrum) during counter-nutation is clock-wise, & on the left body side is counter clock-wise (as viewed from outside the body on each side of course).
As SIJ shifts occur during counter-nutation, the acetabulum shifts slightly posterior; drawing femur along. The femur, being a large radius from acetabulum to knee, magnifies SIJ rotation; evoking asymmetry of ATP & a seemingly shorter tibial plateau on the injured-SIJ side.
The name for these asymmetric postures of the ATP is the “Badgley Book Sign” (BBS), which I have discovered. In another thread reader unroll in my library of thread readers, I further discuss the BBS.
The BBS is measurable, reproducible, & teachable. Counter-nutation of the hemi-pelvis is oft accompanied by a gait whereby the ipsilateral forefoot cants (everts) slightly more lateral & with a distinctive wear pattern on the posterior lateral heel of shoe sole.
Reason for this lateral forefoot eversion is a lateral-posterior shift of the acetabulum axis; as the anterior Iliac bone cants laterally during counter-nutation. The acetabulum axis shift evokes lateral rotation of the femur & eversion of the ipsilateral foot.
People with a positive BBS often have positive ipsilateral Gillette, Fortin, & FABER (Patrick) Signs of SIJ dysfunction. Unlike the latter two signs, the BBS does not rely on pain as a + endpoint.
Other physical findings often associated with BBS are an overlying functional scoliosis (absent when prone) & a shoulder lower on same side as the injured SIJ. These signs reflect influence of gravity on an unstable body tower.
The legs are rigid posts that support the pelvic bony ring, which is a platform upon which is stationed the spine-post that holds up the two shoulder hemi-girdles & the head.
Gravity & orientation of the spine-post as it seats into the vertical inverted wedge of iliac surfaces of the two SIJs is explanatory: the spine-post droops down on the same side the ILL lacks tethering strength & integrity.
A functional Scoliosis is way the body unconsciously compensates to maintain a medial station of the body center of gravity. Muscle systems accomplish this to keep us from falling to the side.
So why does Sciatica occur during SIJ counter-nutation? My regard is that chronic SIJ rotation (subluxation) impinges the presacral neural plexus directly overlying the SIJ ventral sulcus (joint space). Impingement of the presacral plexus has consequences.
As result of presacral plexus impingement, the lower lumbar & sacral nerve roots comprising the pre-sacral plexus are tugged, & mechanical strain causes these roots to be impinged against vertebral foramen, where these roots are fixed as they exit the spine.
An analogous phenomenon is Laseques Sign aroused by sudden foot dorsiflexion evoking long neural tract pull causing nerve root irritation at a site of vertebral disk herniation.
Injury to the ILL seems to occur in women having had childbirth & from menial lifting & bending injuries where torque is involved. Nurses, who regularly lift patients, are particularly prone to permanent SIJ ligament (ILL) injuries.
SACROTUBEROS LIGAMENT SYSTEM (STLS) is other major ligament tethering Sacrum to Ilium. Chronic Sciatica is often attendant with chronic injury to this ligament as well. The STLS has distinct signs & mechanisms of injury. But first anatomy:
The Sacrotuberous Ligament is a long ligament tracking from medial Ischial prominence to inferior regions of the SIJ, where tissues of this ligament contribute to integrity of the inferior SIJ ligament capsule.
Examination of the distal Sacrotuberous Ligament can be made by direct palpation of site of insertion of this ligament upon the Ischial prominence; exceedingly painful if ligament is injured at this bone attachment site.
At the 9th Interdisciplinary World Congress on Low Back & Pelvic Pain, 11/2016, Singapore; Proceedings on line, I presented the first world announcement of an MRI study & images of Sacrotuberous Ligament injury.
In this Study, I demonstrated a method of quantifying a lack of ligament integrity (compared to the normal control side) at the medial Ischial prominences in patients with unilateral SIJ injury & abnormal SIJ subluxation of nutation.
I regard that significant pain aroused by palpation of the medial Ischial prominence & site of insertion of the Sacrotuberous Ligament is a valuable diagnostic sign of injury; one seemingly not previously reported in the medical literature.
The tissue plane of the Sacrotuberous Ligament indicates that it protects against abnormal nutation of the SIJ. When the Sacrotuberous Ligament is chronically injured & has lost tethering strength, then the Sacrotuberous gap abnormally widens; especially while standing.
During the maneuver with patient seated on a firm chair seat & production of the BBS (described above), when the 1” bolster is placed under Ischium of an SIJ containing an injured Sacrotuberous Ligament, ground force of chair seat forces the Sacrotuberous gap to widen.
When the Sacrotuberous gap widens, the Ischial prominence shifts forward. During observation for the Badgley Book Sign (BBS), the ipsilateral ATP lengthens compared to the non-injured SIJ side; as Ischial prominence shifts forward on the chair seat.
When the 1” bolster forces the Ischial prominence forward, the acetabulum follows & ipsilateral femur “functionally lengthens”; causing ipsilateral anterior Tibial plateau to project more forward compared to anterior Tibial plateau on opposite (uninjured SIJ) side.
Another shift that occurs with nutation is a slight medial cant of the anterior Ischium & associated anterior cant of the contained acetabulum axis. These shifts cause a slight internal rotation of the femur.
As result of SIJ nutation, the acetabular axis shift causes the femur to internally rotate. As result of this femur shift, the ipsilateral foot assumes, during gait, an abnormal medially shifted (inverted) posture.
During ambulation persons with Sacrotuberous Ligament laxity experience their foot’s longitudinal axis maintaining a true anterior-posterior saggital longitudinal axis. This unusual foot posture during ambulation is apparent only if one looks for it.
As with ILL injuries, it is common with STLS injuries for shoulders on the SIJ-injured sides to droop during upright postures, & for same reasons described above with ILL injuries.
Biomechanical explanations related to counter-nutation & nutation are my own discoveries. The Badgley Book Sign can be demonstrated within a few minutes in the exam room. Exams for Gillette, Fortin, & FABER Signs take only a few minutes.
The medical literature reports that pain generation within the universe of patients with “chronic low back pain” is caused by SIJ dysfunction in 15-30% of those with “chronic low back pain”.
Therefore, these Provocation Tests of SIJ dysfunction are important to exceed criteria for advancing the patient to the definitive clinical proof of SIJ dysfunction, the SIJ Diagnostic Block (under Fluoroscopy or Ultrasound guidance).
The mechanisms of injury leading to isolated Sacrotuberous Ligament injury are idiosyncratic. Significant falls onto one leg first impacting the ground drives mechanical injury forces up leg & directly into Sacrotuberous Ligament insertion upon the Ischium.
People who fall down cliffs or into holes & land predominantly on one leg can injure the Sacrotuberous Ligament. I have seen this injury in men who have lifted heavy loads & at same time accidentally placed all their body weight onto one leg.
Persons who brace their leg during an impending head-on auto crash incur longitudinal leg biomechanical forces that vector directly into the Sacrotuberous Ligament system; renting & injuring this tissue.
The injury mechanisms I have observed related to specific injuries of the Iliolumbar & Sacrotuberous Ligament Systems are my own hypotheses and my own clinical proofs; as reported in my Studies referenced herein.
Evaluations of musculoskeletal injuries require in-depth information about mechanisms of injury. The only way to understand human soft tissue disorders is with knowledge of the acute or repetitive injury biomechanisms.
Understanding of the vectors of gravity that have occurred during acute and chronic injuries are essential to correct diagnosis of soft tissue injuries.
A characteristic of persons with Sacrotuberous Ligament chronic injury is that they have frequent and sudden falling down episodes. These falls sometimes occur several times per week, & their doctors do not know why.
I reported sudden “giving away” of the leg in my study of “Causes of Fibromyalgia”, on line, at 10th Interdisciplinary World Congress on Low Back & Pelvic Pain, Antwerp, 10/2019. These falls occur when going up or down stairs or even down slanted driveways.
What happens: leg is lifted to take a step & SIJ (with hanging 20# leg) subluxes to an irregular joint-open position. When foot is next planted down, SIJ is suddenly “form closed” (after Dr. A. Vlemming) but into an abnormal offset configuration of joint bone against bone.
Sudden mechanical closure of the sacroiliac joint instantly jogs & jostles offset joint surfaces; causing the contiguous presacral neural plexus to be suddenly punched and stunned.
The stunned presacral plexus is rendered transiently dysesthetic; causing the associated leg to be temporarily paralyzed, paretic, & to “give away” (my theory). These patients report suddenly finding themselves on floor, absent having tripped.
It is curious that when these patients fall down it is sudden & absent premonitory pain that might attend acetabulum-femur subluxation. Since nerves of sciatic neural complex are not dead (only painfully & intermittently impinged) nerve conduction tests (NCT) are negative.
Yet again an instance where Neurologists scratch their heads & invoke psychologic causations to things they cannot explain via their insipid NCT & 2-dimensional snapshots (X-rays & scans) of reclined, non-moving, & non-functioning soft tissues.
Another peculiar characteristic of Sacrotuberous Ligament injury is many days of intense sciatica pain & leg weakness in patients who receive SIJ diagnostic block of anesthetic & corticostreroid. I reported this phenomenon & data within my 8 Antwerp papers (see above).
My theory of phenomenon of leg weakness & prolonged pain after a diagnostic block: injectate extravasates through rent in inferior aspect of the SIJ ligament capsule (insertion site of Sacrotuberous Ligament) & directly into the contiguous sciatic nerve.
The extravasated injectate and contained -cain & steroid derivatives irritate the Sciatic nerve. My next study project hopes to image this extravasation in patients with Sacrotuberous Ligament injury & SIJ nutation.
CONCLUSIONS: Sciatica is a common concomitant of SIJ chronic injury, dysfunction, & subluxation. The Badgley Book Sign is a ready way to determine which SIJ ligament system is injured.
ADDENDUM
INJURED SIJ TREATMENTS:
Generous pain relief can be gained via dorsal medial sacral neural branch blocks & ablation. Prolotherapy with stem cells seems postured to naturally re-establish SIJ ligament integrity.
INJURED SIJ TREATMENTS:
Generous pain relief can be gained via dorsal medial sacral neural branch blocks & ablation. Prolotherapy with stem cells seems postured to naturally re-establish SIJ ligament integrity.
FUSION OF SUBLUXING SACROILIAC JOINTS: SIJ fusion seems in ascendancy, but best way to accomplish fusion is still being debated.
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