Anatomie des douleurs de l’articulation sacro-iliaque

The sacro-iliac joint: A potentially painful enigma. Update on the diagnosis and treatment of pain from micro-trauma

The sacro-iliac joint (SIJ) located at the transition between the spine and the lower limbs is subjected to major shear forces. Mobility at the SIJ is very limited but increases during pregnancy and the post-partum period. Familiarity with the anatomy and physiology of the SIJ is important. The SIJ is a diarthrodial joint that connects two variably undulating cartilage surfaces, contains synovial fluid, and is enclosed within a capsule strengthened by several ligaments. This lecture does not discuss rheumatic or inflammatory diseases of the SIJ, whose diagnosis relies on imaging studies and blood tests. Instead, it focuses on micro-traumatic lesions. Micro-trauma causes chronic SIJ pain, which must be differentiated from hip pain and spinal pain. The diagnosis rests on specific clinical provocation tests combined with a local injection of anaesthetic. Findings are normal from radiographs and magnetic resonance imaging. Non-operative treatment with exercise therapy and stretching aims primarily to strengthen the latissimus dorsi, gluteus, and hamstring muscles to increase SIJ coaptation. Other physical treatments have not been proven effective. Radiofrequency denervation of the dorsal sensory rami has shown some measure of efficacy, although the effects tend to wane over time. Patients with refractory pain may benefit from minimally invasive SIJ fusion by trans-articular implantation of screws or plugs, which has provided good success rates.

Morphometric study of the posterior longitudinal ligament at the lumbar spine

PURPOSE

There are only two descriptions of posterior longitudinal ligament (PLL) at the lumbar spine level but its morphologic characteristics are different to cervical and thoracic levels.

METHOD

Spine explantation (from Th12 to L5) followed by resection of the neural arch and the dural sheath in 13 fresh cadavers was performed. The PLL was isolated from other epidural structures and its width was measured and compared to the vertebral body width at each vertebral levels. It was conducted at a microanatomic study concerning the PLL and the posterior outer annulus fibrosus.

RESULTS

The PLL width was reduced craniocaudaly significantly, becoming thin from L4. The average width of PLL was 7.8 mm at L1 and 1.9 mm at L5. The width decreased gradually from L1 to L5 or abruptly from L4. The ratio of PLL width compared to the vertebral body width was 21% at L1 and 3% at L5. Microanatomic study confirmed that the PLL is less thick at its annulus fibrosus adhesion at L4-L5 and L5-S1. The relationship between the PLL and other epidural structures are discussed.

CONCLUSIONS

The presence and function of the ilio-lumbar ligaments and the articular process orientation of L5-S1 may be explanations for PLL width decrease at L4-L5 and L5-S1. Furthermore, this aspect may be considered as one factor contributing to the occurrence of disc herniations at these levels, which levels are more frequently involved in this pathology.

Intra-observer reliability in three-dimensional kinematic analysis of sacroiliac joint mobility

[Purpose] Physical therapists, osteopathic practitioners, and chiropractors often perform manual tests to evaluate sacroiliac joint (SIJ) mobility. However, the available evidence demonstrates an absence of reliability in these tests and in investigations with kinematic analysis. The aim of this study was to verify the three-dimensional kinematic reliability in SIJ movement measurements. [Subjects] This cross-sectional study analyzed 24 healthy males, aged between 18 and 35 years. [Methods] Three-dimensional kinematic analysis was performed for measurements of posterior superior iliac displacement and greater trochanter (femur) displacement during hip flexion movement in an orthostatic position. The distance variations were measured from a reference point in 3 blocks. The intra-observer reliability was compared with the mean of three 3 blocks using the interclass correlation coefficient (ICC) and a 99% significance level. [Results] The measurements indicated a strong correlation among blocks: ICC = 0.94 for right side SIJ and ICC = 0.91 for left side SIJ. The mean displacement between the reference points was 7.7 mm on the right side and 8.5 mm on the left side. [Conclusion] Our results indicate that three-dimensional kinematic analysis can be used for SIJ mobility analyses. New studies should be performed for subjects with SIJ dysfunction to verify the effectiveness of this method.