Annelies Pool-Goudzwaard

The posterior layer of the thoracolumbar fascia : its function in load transfer from spine to legs

Study Design The superficial and deep lamina of the posterior layer of the thoracolumbar fascia have been studied anatomically and biomechanically. In embalmed human specimens, the posterior layer has been loaded by simulating the action of various muscles. The effect has been studied using raster photography. Objectives To study the role of the posterior layer of the thoracolumbar fascia in load transfer between spine, pelvis, legs, and arms. Summary of Background Data It has been determined whether muscles such as the gluteus maximus, latissimus dorsi, erector muscle, and biceps femoris are functionally coupled via the thoracolumbar fascia. The caudal relations of the posterior layer of the thoracolumbar fascia have not been previously studied. Methods Dissection was directed to the bilaminar posterior layer of the thoracolumbar fascia of 10 human specimens. The superficial and deep lamina were studied using visual inspection and raster photography. Tension to the posterior layer of the fascia was simulated by traction to various muscles and measured by studying the displacement in the posterior layer. Results Traction to a variety of muscles caused displacement of the posterior layer. This implies that in vivo, the superficial lamina will be tensed by contraction of various muscles, such as the latissimus dorsi, gluteus maximus and erector muscle, and the deep lamina by contraction of the biceps femoris. Caudal to the level of L4 (in some specimens, L2-L3), tension in the posterior layer was transmitted to the contralateral side. Conclusions Anatomic structures normally described as hip, pelvic, and leg muscles interact with socalled arm and spinal muscles via the thoracolumbar fascia. This allows for effective load transfer between spine, pelvis, legs, and arms-an integrated system. Specific electromyographic studies should reveal whether the gluteus maximus muscle and contralateral latissimus dorsi muscle are functionally coupled, especially during rotation of the trunk. In that case, the combined action of these muscles assists in rotating the trunk, while simultaneously stabilizing the lower lumbar spine and sacroiliac joints.

The function of the long dorsal sacroiliac ligament: Its implication for understanding low back pain

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 sacrotuberous 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.

Symptomatic pelvic organ prolapse and possible risk factors in a general population.

OBJECTIVE We sought to examine the prevalence of pelvic organ prolapse (POP) symptoms and risk factors in a general white population. STUDY DESIGN This was a cross-sectional study. All female residents aged 45-85 years in a small Dutch city received validated questionnaires. Women were classified as symptomatic if they reported feeling and/or seeing vaginal bulge. RESULTS Response rate was 62.7% (1869/2979). Prevalence of POP was 11.4%. Multivariate analysis revealed POP symptoms during pregnancy, a maternal history of POP, and heavy physical work, with a total population-attributable risk of 46%. CONCLUSION There is high prevalence of symptomatic POP in a general white population of which independent risk factors are POP symptoms during pregnancy, a maternal history of POP, and heavy physical work. Clinicians should focus on risk factors in counseling of (pregnant) women to inform women to be aware of further exposures for themselves and their daughters.

Relations between pregnancy-related low back pain, pelvic floor activity and pelvic floor dysfunction.

To assess the occurrence of pelvic floor dysfunction (PFD) in pregnancy- related low back and pelvic pain (PLBP) patients, a cross-sectional study was performed, comprising 77 subjects. Each subject underwent physical assessment, and filled in the Urogenital Distress Inventory completed with gynaecological questions. Differences in the presence of PFD between PLBP patients and healthy controls as well as differences in pelvic floor muscle activity were tested for significance. Interaction by age and vaginal delivery were tested. PFD occurred in 52% of all PLBP patients, significantly more than in the healthy control group. In PLBP patients a significantly increased activity of the pelvic floor muscles could be demonstrated with respect to healthy controls. The occurrence of PFD and PLBP was influenced by a confounding effect of age. Clinicians should be aware of the relation between PLBP and PFD and hence address both problems at the same time.

The iliolumbar ligament: its influence on stability of the sacroiliac joint

STUDY DESIGN In human specimens the influence of the iliolumbar ligament on sacroiliac joint stability was tested during incremental moments applied to the sacroiliac joints. OBJECTIVES To assess whether the iliolumbar ligament is able to restrict sacroiliac joint mobility in embalmed cadavers. BACKGROUND Firstly, the sacroiliac joint can play an important role in non-specific low back pain; hence, its mobility and stability are of special interest. Secondly, the iliolumbar ligament is considered to be an important source of chronic low back pain. Data on a functional relation between the iliolumbar ligament and sacroiliac joint mobility are lacking. METHODS In 12 human specimens an incremental moment was applied to the sacroiliac joint to induce rotation in the sagittal plane. After the assessment of the relationship between rotation angle and moment in the intact situation, specific parts of the iliolumbar ligaments were transected. After each partial transection the measurements were repeated. RESULTS Sacroiliac joint mobility in the sagittal plane was significantly increased after a total cut of both iliolumbar ligaments. This increase was in particular due to the transection of a specific part of the iliolumbar ligament, the ventral band. CONCLUSIONS The main conclusions are: (a) the iliolumbar ligaments restrict sacroiliac joint sagittal mobility; (b) the ventral band of the iliolumbar ligament contributes most to this restriction. RELEVANCE In embalmed human cadavers, the mobility of the sacroiliac joint increases after sequential cutting of specific parts of the iliolumbar ligaments. It can be expected that severance of this ligament during surgery will lead to increase of mobility and hence loss of stability of the sacroiliac joint. As a consequence adjacent structures will be affected. This may well be a cause of pain in patients with failed back surgery.

Mobility of the pelvic joints in pregnancy-related lumbopelvic pain: a systematic review.

About 45% of all pregnant women and 25% of all women postpartum suffer from pelvic girdle pain and/or low back pain (PLPP). It has been suggested that increased motion of the three joints in the pelvic ring is one of the causes of PLPP. However, in spite of the availability of high technology the relation between enlarged motion of the pelvic joints and pain remains unclear. This article presents 14 studies on this topic, of which 8 are of sufficient quality to draw conclusions. The conclusion is that, during the last months of pregnancy and the first 3 weeks after delivery, motion of the pelvic girdle joints is 32–68% larger in patients with PLPP than in healthy controls. The overlap in the range of symphyseal motion between PLPP patients and healthy controls is too large to use motion as a diagnostic tool in individual cases. The findings support the idea that enlarged motion is one of the factors that causes PLPP and justifies treatment with measures to reduce this motion. Target Audience: Obstetricians & Gynecologists, Family Physicians Leaning Objectives: After completion of this article, the reader should be able to explain the presumptive mechanisms for pregnancy-related low back pain, identify the difficulties with literature regarding objective diagnostic criteria for pregnancy-related low back pain, and outline three possible treatment strategies for pregnancy-related low back pain.

The sacroiliac part of the iliolumbar ligament

The iliolumbar ligament has been described as the most important ligament for restraining movement at the lumbosacral junction. In addition, it may play an important role in restraining movement in the sacroiliac joints. To help understand its presumed restraining effect, the anatomy of the ligament and its orientation with respect to the sacroiliac joints were studied in 17 cadavers. Specific dissection showed the existence of several distinct parts of the iliolumbar ligament, among which is a sacroiliac part. This sacroiliac part originates on the sacrum and blends with the interosseous sacroiliac ligaments. Together with the ventral part of the iliolumbar ligament it inserts on the medial part of the iliac crest, separate from the interosseous sacroiliac ligaments. Its existence is verified by magnetic resonance imaging and by cryosectioning of the pelvis in the coronal and transverse plane. Fibre direction, length, width, thickness and orientation of the sacroiliac part of the iliolumbar ligament are described. It is mainly oriented in the coronal plane, perpendicular to the sacroiliac joint. The existence of this sacroiliac part of the iliolumbar ligament supports the assumption that the iliolumbar ligament has a direct restraining effect on movement in the sacroiliac joints.

Biomechanical model study of pelvic belt influence on muscle and ligament forces

Many patients with low back and/or pelvic girdle pain feel relief after application of a pelvic belt. External compression might unload painful ligaments and joints, but the exact mechanical effect on pelvic structures, especially in (active) upright position, is still unknown. In the present study, a static three-dimensional (3-D) pelvic model was used to simulate compression at the level of anterior superior iliac spine and the greater trochanter. The model optimised forces in 100 muscles, 8 ligaments and 8 joints in upright trunk, pelvis and upper legs using a criterion of minimising maximum muscle stress. Initially, abdominal muscles, sacrotuberal ligaments and vertical sacroiliac joints (SIJ) shear forces mainly balanced a trunk weight of 500N in upright position. Application of 50N medial compression force at the anterior superior iliac spine (equivalent to 25N belt tension force) deactivated some dorsal hip muscles and reduced the maximum muscle stress by 37%. Increasing the compression up to 100N reduced the vertical SIJ shear force by 10% and increased SIJ compression force with 52%. Shifting the medial compression force of 100N in steps of 10N to the greater trochanter did not change the muscle activation pattern but further increased SIJ compression force by 40% compared to coxal compression. Moreover, the passive ligament forces were distributed over the sacrotuberal, the sacrospinal and the posterior ligaments. The findings support the cause-related designing of new pelvic belts to unload painful pelvic ligaments or muscles in upright posture.

Biomechanical analysis of reducing sacroiliac joint shear load by optimization of pelvic muscle and ligament forces

Effective stabilization of the sacroiliac joints (SIJ) is essential, since spinal loading is transferred via the SIJ to the coxal bones, and further to the legs. We performed a biomechanical analysis of SIJ stability in terms of reduced SIJ shear force in standing posture using a validated static 3-D simulation model. This model contained 100 muscle elements, 8 ligaments, and 8 joints in trunk, pelvis, and upper legs. Initially, the model was set up to minimize the maximum muscle stress. In this situation, the trunk load was mainly balanced between the coxal bones by vertical SIJ shear force. An imposed reduction of the vertical SIJ shear by 20% resulted in 70% increase of SIJ compression force due to activation of hip flexors and counteracting hip extensors. Another 20% reduction of the vertical SIJ shear force resulted in further increase of SIJ compression force by 400%, due to activation of the transversely oriented M. transversus abdominis and pelvic floor muscles. The M. transversus abdominis crosses the SIJ and clamps the sacrum between the coxal bones. Moreover, the pelvic floor muscles oppose lateral movement of the coxal bones, which stabilizes the position of the sacrum between the coxal bones (the pelvic arc). Our results suggest that training of the M. transversus abdominis and the pelvic floor muscles could help to relieve SI-joint related pelvic pain.

Face validity and reliability of the first digital assessment scheme of pelvic floor muscle function conform the new standardized terminology of the International Continence Society.

To test the face validity and reliability of a new digital pelvic floor muscle function (PFMF) assessment scheme that was designed on the basis of the recently standardized terminology of the International Continence Society.