The biomechanical influence of the facet joint orientation and the facet tropism in the lumbar spine

Facet tropism and facet joint orientation: risk factors for the development of early biochemical alterations of lumbar intervertebral discs

“…In the spine model of Kim et al, increased FJ orientation led to an elevated contact force of FJ under torsion, made the FJ more vulnerable to anterior shear forces and raised intradiscal pressure, which led to IVD degeneration. This IVD degeneration was aggravated by FT due to enhanced intradiscal pressure and anterior shear forces, which is in accordance with our results 28 . We found 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 no significant difference of gagCEST values in segments with an FJ orientation <45 and FT compared to segments with an FJ orientation >45 without FT.…”

“…This finding suggests that sagittal FJ orientation had no greater influence on GAG content of lumbar IVDs than FT that was reported by Boden et al who found pronounced degenerative spine changes in more sagittal FJ 10 . In contrast to the results of Boden and colleagues, Kim et al found a higher impact of FT on disc alterations compared to sagittal FJ orientation in the spine model 28 . This may be the result of the FT models used by Kim et al, which included 50 , 55 and 60 with a moderate asymmetry between left and right FJ.…”

“…Our results corroborate previous reports on IVD degeneration and FT 5,27 . Kim et al reported an increased disc stress and contact force due to FT in a spine model 28 . Biomechanically, increased contact force of FJ under torsion results in an increased vulnerability of FJ to anterior shear forces.…”

Facet tropism: possible role in the pathology of lumbar disc herniation in adolescents

“…A finite element analysis found that FT could make the lumbar segment vulnerable to shear force. 15 FT may have a different role in the pathology of LDH in adolescents and adults. Murtagh et al investigated the association between FT and LDH in adults, and found that FT was not a correlative factor for LDH.…”

“…28 A recent finite element research study confirmed that FT could make the corresponding segment more vulnerable to external movements or anterior shear force. 15 Therefore, FT may play a more important role in the development of LDH in adolescents than in adults. In the present study, the authors investigated the association between FT and LDH in adolescents.…”