Background: Kyphosis is a spine deformity that can lead to falls and reduced quality of life. Peroxisome proliferator-activated receptor gamma coactivator 1α (PGC-1α) regulates mitochondrial biogenesis and is important for proper functioning of skeletal muscle, including the paraspinal muscles, which support and allow movement of the spine. The role of PGC-1α in paraspinal muscles in lumbar kyphosis has not been examined. We also examined the expressions of the proinflammatory cytokines tumor necrosis factor (TNF)-α and interleukin (IL)-6. Methods: We obtained paraspinal muscle specimens from 12 patients who underwent posterior lumbar surgery. RNA was isolated from these samples, and quantitative PCR was performed to compare the expression levels of PGC-1α, TNF-α, and IL-6 mRNA between patients with decreased lumbar lordosis (LL) and normal LL patients. Results: TNF-α and IL-6 mRNA expressions in paraspinal muscles were significantly higher in the decreased LL group than in the normal LL group (P=0.048 for both). PGC-1α mRNA expression was slightly increased in the decreased LL group, but the difference was not significant. Age was significantly positively correlated with PGC-1α mRNA expression (P=0.010). PGC-1α mRNA expression was significantly positively correlated with TNF-α mRNA expression (P=0.022). LL was significantly negatively correlated with PGC-1α, TNF-α, and IL-6 mRNA expressions (P=0.015, 0.036, and 0.010, respectively). Conclusion: TNF-α and IL-6 mRNA expressions in paraspinal muscles were significantly higher in the decreased LL group than in the normal LL group. LL was significantly negatively correlated with PGC-1α, TNF-α, and IL-6 mRNA expressions. PGC-1α mRNA expression levels in paraspinal muscles may be affected by lumbar kyphosis.

Progressive and generalized loss of skeletal muscle mass (SMM) and strength are characteristics of sarcopenia. However, the impact of appendicular and trunk SMM and back extensor strength (BES) on spinal sagittal alignment remains unclear. Herein, we investigate the relationship between these factors and spinal sagittal alignment. In total, 202 women without vertebral fractures (median age, 66.9 years; interquartile range, 61.4–71.9 years) were analyzed at an orthopedic outpatient clinic. Pelvic incidence (PI), lumbar lordosis (LL), sagittal vertical axis (SVA), and pelvic tilt (PT) were measured on whole spine radiographs. Body mass index (BMI), appendicular and trunk relative SMM index, and BES were also evaluated. These measurements were compared between spinal sagittal alignment groups using the Mann–Whitney U test. Finally, the factors contributing to abnormal alignment were analyzed using multiple logistic regression analysis. BES was significantly lower in all abnormal sagittal alignment groups, as defined by PI-LL (≥ 10°), SVA (≥4 cm), and PT (≥20°) (all P < 0.001). On multivariate analysis, BES was a contributing factor for abnormal PI-LL (P < 0.001), SVA (P = 0.001), and PT (P < 0.001). Conversely, a decrease in appendicular and trunk relative SMM index did not statistically affect abnormal spinal sagittal alignment. BES was associated with changes in spinal sagittal alignment; however, SMM, which is often used for diagnosing sarcopenia, did not affect spinal sagittal alignment.

Safe excision of spinal cord tumors depends on sufficient visualization of the tumor and surrounding structures. In patients with spinal cord tumor adjacent to a stenotic spinal canal, extensive bony decompression proximal and distal to the tumor should be considered for safer excision of the tumor. Extensive wide laminectomy is one choice for such cases, but postoperative problems such as kyphotic deformity remain a concern. A 76-year-old man and a 60-year-old woman presented with symptomatic intradural extramedullary spinal cord tumors in the cervical spine. Both patients showed a combination of spondylotic changes in the cervical spine and stenotic condition at the level of the tumor. Both tumors were successfully resected through open-door laminoplasty with hydroxyapatite (HA) spacers, with the tumor located on the side of the laminoplasty. Histological diagnosis was schwannoma for both tumors. HA spacers completely bonded to the host bone and did not interfere with postoperative magnetic resonance imaging (MRI) of the inside of the spinal canal. Cervical spine alignment was maintained at the final follow-up of 6 years in both cases. Laminoplasty with HA spacers enabled successful tumor extirpation, reliable MRI follow-up after surgery, and maintenance of normal cervical spine alignment. Laminoplasty with HA spacers represents a good option for the treatment of cervical spinal cord tumor in patients combined with spinal stenosis.

Partial to complete paralysis following spinal cord injury (SCI) causes deterioration in health and has severe effects on the ability to perform activities of daily living. Following the discovery of neural plasticity, neurorehabilitation therapies have emerged that aim to reconstruct the motor circuit of the damaged spinal cord. Functional electrical stimulation (FES) has been incorporated into devices that reconstruct purposeful motions in the upper and lower limbs, the most recent of which do not require percutaneous electrode placement surgery and thus enable early rehabilitation after injury. FES-based devices have shown promising results for improving upper limb movement, including gripping and finger function, and for lower limb function such as the ability to stand and walk. FES has also been employed in hybrid cycling and rowing to increase total body fitness. Training using rehabilitation robots is advantageous in terms of consistency of quality and quantity of movements and is particularly applicable to walking training. Initiation of motor reconstruction at the early stage following SCI is likely to advance rapidly in the future, with the combined use of technologies such as regenerative medicine, brain machine interfaces, and rehabilitation robots with FES showing great promise.