ABSTRACT
Methods@#Nineteen volunteers (16 men, three women) lifted a 60-kg doll from a seated position to a standing position. The first transfer was performed without the HAL for Care Support, and the second was performed with the HAL for Care Support assistive robot. We evaluated transfer performance, the visual analog scale (VAS) score for lumbar fatigue, and electromyogram analyses of the trunk and hip. @*Results@#Four participants (two men, two women) succeeded with the HAL for Care Support even though they were unable to perform the task without it. The mean lumbar fatigue VAS score for all participants without the HAL for Care Support was 62 mm, while that with it was 43 mm. With lumbar assistance from the HAL for Care Support, subjective lumbar fatigue during the transfer decreased significantly. A power analysis indicated adequate statistical power to detect a difference in the VAS score for lumbar fatigue (0.99). The activity of the left gluteus maximus alone increased significantly during transfers with the HAL for Care Support. No adverse events occurred during use of the HAL for Care Support for transfers. @*Conclusions@#The HAL for Care Support was able to reduce lumbar load in a simulated patient transfer.
ABSTRACT
Methods@#Cases of 50 patients with ASD who underwent long spinal fusion (>9 levels) with S2AI screws were retrospectively reviewed. Loosening of S2AI screws and S1 pedicle screws and bone fusion at the level of L5–S1 at 2 years after surgery were investigated using computed tomography. In addition, risk factors for loosening of S2AI screws were determined in patients with ASD. @*Results@#At 2 years after surgery, 33 cases (66%) of S2AI screw loosening and six cases (12%) of S1 pedicle screw loosening were observed. In 40 of 47 cases (85%), bone fusion at L5–S1 was found. Pseudarthrosis at L5–S1 was not significantly associated with S2AI screw loosening (19.3% vs. 6.3%, p=0.23), but significantly higher in patients with S1 screw loosening (83.3% vs. 4.9%, p<0.001). On multivariate logistic regression analyses, high upper instrumented vertebra (UIV) level (T5 or above) (odds ratio [OR], 4.4; 95% confidence interval [CI], 1.0–18.6; p=0.045) and obesity (OR, 11.4; 95% CI, 1.2–107.2; p=0.033) were independent risk factors for S2AI screw loosening. @*Conclusions@#High UIV level (T5 or above) and obesity were independent risk factors for S2AI screw loosening in patients with lumbosacral fixation in surgery for ASD. The incidence of lumbosacral fusion is associated with S1 screw loosening, but not S2AI screw loosening.
ABSTRACT
Methods@#Cases of 50 patients with ASD who underwent long spinal fusion (>9 levels) with S2AI screws were retrospectively reviewed. Loosening of S2AI screws and S1 pedicle screws and bone fusion at the level of L5–S1 at 2 years after surgery were investigated using computed tomography. In addition, risk factors for loosening of S2AI screws were determined in patients with ASD. @*Results@#At 2 years after surgery, 33 cases (66%) of S2AI screw loosening and six cases (12%) of S1 pedicle screw loosening were observed. In 40 of 47 cases (85%), bone fusion at L5–S1 was found. Pseudarthrosis at L5–S1 was not significantly associated with S2AI screw loosening (19.3% vs. 6.3%, p=0.23), but significantly higher in patients with S1 screw loosening (83.3% vs. 4.9%, p<0.001). On multivariate logistic regression analyses, high upper instrumented vertebra (UIV) level (T5 or above) (odds ratio [OR], 4.4; 95% confidence interval [CI], 1.0–18.6; p=0.045) and obesity (OR, 11.4; 95% CI, 1.2–107.2; p=0.033) were independent risk factors for S2AI screw loosening. @*Conclusions@#High UIV level (T5 or above) and obesity were independent risk factors for S2AI screw loosening in patients with lumbosacral fixation in surgery for ASD. The incidence of lumbosacral fusion is associated with S1 screw loosening, but not S2AI screw loosening.
ABSTRACT
Objective: To treat vertebral fractures with posterior wall injury in the elderly, vertebral bone grafting is generally performed through a posterior transpedicular approach, combined with pedicle screw fixation. An autologous bone is ideal to treat this disorder. However, harvesting autologous bones from the elderly with osteoporosis is limited by the amount and quality of available autologous bone. Thus, we developed a bone-grafting substitute. The newly developed unidirectional porous β-tricalcium phosphate, with a porosity of 57% (UDPTCP; Affinos®, Kuraray Co., Ltd., Tokyo, Japan), is used in the bone-grafting procedure. This is the first report of UDPTCP used as an artificial bone graft in patients with an acute vertebral burst fracture.Materials and Methods: UDPTCP (mean: 4.2 g) was implanted through the pedicle, and posterior instrumentation was achieved with pedicle screws in five elderly patients. Resorption of UDPTCP and substitution with the autologous bone were evaluated on computed tomography (CT) and plain X-ray performed immediately and at 3, 6, and 12 months after the operation.Results: In case 1, the pedicle screws did not loosen, and UDPTCP was completely resorbed and replaced with the autologous bone at 3 postoperative months. In the other four cases, although the pedicle screws or the caudal part loosened because of osteoporosis, resorption of UDPTCP was observed at 3 postoperative months. At 6 postoperative months, progressive substitution with the autologous bone was confirmed, and at 12 postoperative months, formation of the good autologous bone was confirmed.Conclusion: This preliminary case series demonstrated that the newly developed UDPTCP shows good clinical potential as a bone-graft substitute for acute vertebral burst fractures in the elderly, including patients with osteoporosis.