BackgroundThe typical degeneration of the vertebral endplate shown in MRI imaging is Modic change. The aim of this study was to observe the distribution of the Modic changes of vertebral endplate in degenerative thoracolumbar/lumbar kyphosis (DTK/LK) patients and analyse the correlation between spinal-pelvic parameters and Modic changes.MethodsThe imaging data of 58 patients diagnosed with DTK/LK (coronal Cobb angle<10°with sagittal imbalance) in our hospital from March 2016 to May 2017 were reviewed retrospectively. Observe the prevalence, type and distribution characteristics of Modic changes occurred at the vertebral endplate from T10 to S1;analyse the correlation between Modic changes and disc degeneration, the sagittal vertical axis (SVA), thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT) and pelvic incidence (PI).ResultsOf the 928 intervertebral endplates from 58 patients, Modic changes occurred at 90 endplates (9.7%) of 30 patients (51.7%). 5 endplates (0.5%) of 3 patients (5.2%) were classified as type I, 68 endplates (7.3%) of 25 patients (43.1%) as type II, 17 endplates (1.8%) of 9 patients (15.5%) as type III. The location of the degenerative endplates: 2 (2.2%) superior and inferior endplates of L1, 3 (3.3%) inferior endplates of T11and T12, 4 (4.4%) superior endplates of L2, 6 (6.7%) inferior endplates of L2 and L4, 8 (8.9%) superior endplates of S1, 9 (10%) superior endplates of L3, 11 (12.2%) inferior endplates of L3 and L5 and superior endplates of L4, 12 (13.3%) superior endplates of L5. Modic changes were significantly correlated with intervertebral disc degeneration (r = 0.414, p<0.01); the amount of Modic changes were significantly correlated with LL (r = -0.562, p = 0.012), SS (r = -0.46, p = 0.048), PT (r = 0.516, p = 0.024).ConclusionsMost of the Modic changes of vertebral endplates in DTK/LK patients are type II which are prevalently located at L3/4, L4/5 and L5/S1. The Modic changes of vertebral endplates were found to be significantly correlated with disc degeneration, LL, SS, and PT.

HS was superior to ACDF with regard to equivalent clinical outcomes in the mid-long-term follow-up. Furthermore, HS was superior in the maintenance of ROM and had less impact on its adjacent segments. The efficacy of HS is similar to that of CADR.

Background:Thoracolumbar junction (TLJ) is the transitional area between the lower thoracic spine and the upper lumbar spine. Vertebral compression fractures and proximal junctional kyphosis following spine surgery often occur in this area. Therefore, the study of development and mechanisms of thoracolumbar junctional degeneration is important for planning surgical management. This study aimed to review radiological parameters of thoracolumbar junctional degenerative kyphosis (TLJDK) in patients with lumbar degenerative kyphosis and to analyze compensatory mechanisms of sagittal balance.Methods:From January 2016 to March 2017, patients with lumbar degenerative kyphosis were enrolled in this radiographic study. Patients were divided into two groups according to thoracolumbar junctional angle (TLJA): the non-TLJDK (NTLJDK) group (TLJA <10°) and the TLJDK group (TLJA ≥10°). Complete spinopelvic radiographic parameters were analyzed and compared between two groups. Pearson or Spearman correlation coefficients and independent two-sample t-test or Mann-Whitney U-test were used.Results:A total of 77 patients with symptomatic sagittal imbalance due to lumbar degenerative kyphosis were enrolled in this study. There were 34 patients in NTLJDK group (TLJA <10°) and 43 patients in TLJDK group (TLJA ≥10°). The median angle of lumbar lordosis (LL) in the NTLJDK or TLJDK groups was 23.40° (18.50°, 29.48°) or 19.50° (13.30°, 24.55°), respectively. The median TLJAs in all patients and both groups were −11.20° (−14.60°, −4.80°), −3.70° (−7.53°, −1.73°), and −14.30° (−17.45°, −13.00°), respectively. In the NTLJDK group, LL was correlated with thoracic kyphosis (TK; r = −0.400, P = 0.019), sacral slope (SS; r = 0.681, P < 0.001), and C7-sagittal vertical axis (r = −0.402, P = 0.018). In the TLJDK group, LL was correlated with TK (r = −0.345, P = 0.024), SS (r = 0.595, P < 0.001), and pelvic tilt (r = −0.363, P = 0.017). There were significant differences in LL, TLJA, TK, SS, and pelvic incidence (PI) between two groups.Conclusions:Although TLJDK is common in patients with lumbar degenerative kyphosis, it might be generated by special characteristics of morphology and biomechanics of the TLJ. To maintain sagittal balance, pelvis back tilt might be more important in patients with TLJDK, whereas thoracic curve changes might be more important in patients without TLJDK.

This study aims to explore the influence of bone resorption of the spinous process after single-segment interspinous process device (IPD) implantation on the biomechanics of the lumbar spine.The 3D finite element model of the lumbar spine (L3-L5) was modified, and 2 models that simulated the presence and absence of bone resorption of the spinous process were developed using an IPD (Wallis). Its biomechanical effects, such as change in range of motion (ROM) and intervertebral disc and facet stress, were introduced at operative (L4/5) and adjacent (L3/4) levels.Compared with the INT model, the Wallis model and Wallis-BR model had similar ROMs in lateral flexion and rotation. However, the Wallis model had a lower L3–5 ROM in flexion (20.4% lower) and extension (26.4% lower), and L4-L5 ROM in flexion (74.1% lower) and extension (70.8% lower), while the overall ROM of the Wallis-BR model was greater than that of the Wallis model. The stress on the L3/L4 intervertebral disc and facets was similar for all 3 models. Compared with the INT model and Wallis-BR model, the stress on the L4/L5 intervertebral disc and facets under all movements significantly decreased in the Wallis model. The stress on the L5 process was greater than that on the L4 process in both the Wallis model and Wallis-BR model, and the load on the processes that underwent bone resorption was lower than that of the Wallis model.The function of the IPD slowly decreased with the occurrence of bone resorption of the interspinous process. This bone remodeling may be associated with high stress after IPD implantation.