In order to examine the personal space perception, measurements were conducted on both elbows in 14 men and 46 women. Each subject, with his (or her) eyes closed and with his upper arm fixed horizontally, was instructed to stop the vertical and horizontal swing motion of his lower arm at the point he considered to be the middle of the range of possible motion on the front and side of plane at his shoulder, and this was repeated ten times. In various conditions, similar measurements were also done to study factors affecting the personal space perception in 14 men.
Mean values of bisected angles in percentage against range of motion were deviated from the middle points in the direction of the elbow extension, although there were large differences between the individuals. The deviation was smallest in the vertical. side of plane, and was larger in the horizontal plane than that in the vertical plane. The deviation was not so much affected by the various conditions.
It was suggested that the gain of the personal space perception is higher in the elbow extension than in the elbow flexion and its difference is larger in the horizontal plane than in vertical plane of the human elbow joint.

The present study was performed to investigate the effect of long distance walking upon physical functions for healthy male subjects. The first experiment was carried out in 1977, the second, in 1978, and the third, in 1979 in each autum season. At the first experiment, subjects began walking upon having breakfast, then ate and drank noting during first 30km, and took some foods during another 26km. Twelve hours and fifty minutes of time was spent for 56km walking including 15, 60, and 30 minutes rest periods in between. In the second experiment, subjects ate nothing after dinner of the previous evening and 35km walking took 6 hours during which some rest periods were taken for blood sampling. The third was 80km walking for two days. Subjects walked 40km in 8 hours in the first day and on the following day they walked 40km in ten hours and twenty minutes. They took foods and rest freely.
From the view points of the changes in blood and urinary recordings obtained from those three experiments, the influences of long distance walking on the body indicate as follows ;
1) In case of long distance walking while nothing to eat and drink, the rate of serum saturated fatty acids composition decreased and unsaturated fatty acids increased.
2) In a fasting state, blood glucose gradually decreased, LDH activity increased and blood lactate, GOT and GPT activity presented no significant changes on long distance walking.
3) It was shown that the longer distance to walk, the lesser tendency in blood triglyceride even though subjects take a carbohydrate rich diet while walking.
4) In fasting state, less than 35km walking without foods, the stress to the body seemed not to be critical.
5) More than 40km walking in a day, even though taking meals, would result a significantly severe stress for body.
6) As long as usual meals are taken, 80km walking for two days continuously, 40km in each day, would not result in such a physical stress over the following days.

Objective: Spine surgeons are often at risk of radiation exposure due to intraoperative fluoroscopy, leading to health concerns such as carcinogenesis. This is due to the increasing use of percutaneous pedicle screw (PPS) in spinal surgeries, resulting from the widespread adoption of minimally invasive spine stabilization. This study aimed to elucidate the effectiveness of smart glasses (SG) in PPS insertion under fluoroscopy. Methods: SG were used as an alternative screen for fluoroscopic images. Operators A (2-year experience in spine surgery) and B (9-year experience) inserted the PPS into the bilateral L1–5 pedicles of the lumbar model bone under fluoroscopic guidance, repeating this procedure twice with and without SG (groups SG and N-SG, respectively). Each vertebral body’s insertion time, radiation dose, and radiation exposure time were measured, and the deviation in screw trajectories was evaluated. Results: The groups SG and N-SG showed no significant difference in insertion time for the overall procedure and each operator. However, group SG had a significantly shorter radiation exposure time than group N-SG for the overall procedure (109.1 ± 43.5 seconds vs. 150.9 ± 38.7 seconds; p = 0.003) and operator A (100.0 ± 29.0 seconds vs. 157.9 ± 42.8 seconds; p = 0.003). The radiation dose was also significantly lower in group SG than in group N-SG for the overall procedure (1.3 ± 0.6 mGy vs. 1.7 ± 0.5 mGy; p = 0.023) and operator A (1.2 ± 0.4 mGy vs. 1.8 ± 0.5 mGy; p = 0.013). The 2 groups showed no significant difference in screw deviation. Conclusion The application of SG in fluoroscopic imaging for PPS insertion holds potential as a useful method for reducing radiation exposure.

Objective: To evaluate the preoperative and perioperative predictors of persistent leg numbness following lumbar fusion in patients aged ≥ 75 years. Methods: This single-center retrospective study examined 304 patients aged ≥ 75 years who underwent lumbar fusion for lumbar degenerative disease (102 men, 202 women; mean age, 79.2 [75–90] years). The visual analogue scale (VAS) score for leg numbness was examined preoperatively and at 2 years postoperatively. The persistent leg numbness group included patients with a 2-year postoperative VAS score for leg numbness ≥ 5 points. The demographic data were also reviewed. A multivariate stepwise logistic regression analysis was performed for variables with univariate analysis values of p < 0.2 on univariate analysis. Results: In total, 71 patients (23.4%) experienced persistent postoperative leg numbness. Multivariate logistic regression analysis revealed that a history of lumbar decompression, longer symptom duration, and a preoperative VAS score for leg numbness ≥ 5 points were associated with greater postoperative persistent leg numbness following lumbar fusion. In contrast, other factors, such as sex, body mass index, vertebral fracture, diabetes mellitus, depression, symptom duration, dural injury, operative time, and estimated blood loss, were not. Conclusion A history of preoperative lumbar decompression, longer symptom duration, and greater preoperative VAS scores for leg numbness were preoperative predictors of persistent postoperative leg numbness following lumbar fusion in older patients. Although lumbar fusion is expected to improve leg numbness, surgeons should consider the surgical history, duration, and preoperative numbness intensity and explain the potential postoperative persistent leg numbness in advance.

Objective: To elucidate the patient characteristics and outcomes of emergency surgery for spinal metastases and identify risk factors for emergency surgery. Methods: We prospectively analyzed 216 patients with spinal metastases who underwent palliative surgery from 2015 to 2020. The Eastern Cooperative Oncology Group performance status, Barthel index, EuroQol-5 dimension (EQ5D), and neurological function were assessed at surgery and at 1, 3, and 6 months postoperatively. Multivariate analysis was performed to identify risk factors for emergency surgery. Results: In total, 146 patients underwent nonemergency surgery and 70 patients underwent emergency surgery within 48 hours of diagnosis of a surgical indication. After propensity score matching, we compared 61 patients each who underwent nonemergency and emergency surgery. Regardless of matching, the median performance status and the mean Barthel index and EQ5D score showed a tendency toward worse outcomes in the emergency than nonemergency group both preoperatively and 1 month postoperatively, although the surgery greatly improved these values in both groups. The median survival time tended to be shorter in the emergency than nonemergency group. The multivariate analysis showed that lesions located at T3–10 (p = 0.002; odds ratio [OR], 2.92; 95% confidence interval [CI], 1.48–5.75) and Frankel grades A–C (p < 0.001; OR, 4.91; 95% CI, 2.45–9.86) were independent risk factors for emergency surgery. Conclusion Among patients with spinal metastases, preoperative and postoperative subjective health values and postoperative survival are poorer in emergency than nonemergency surgery. Close attention to patients with T3–10 metastases is required to avoid poor outcomes after emergency surgery.

Objective: Spine surgeons are often at risk of radiation exposure due to intraoperative fluoroscopy, leading to health concerns such as carcinogenesis. This is due to the increasing use of percutaneous pedicle screw (PPS) in spinal surgeries, resulting from the widespread adoption of minimally invasive spine stabilization. This study aimed to elucidate the effectiveness of smart glasses (SG) in PPS insertion under fluoroscopy. Methods: SG were used as an alternative screen for fluoroscopic images. Operators A (2-year experience in spine surgery) and B (9-year experience) inserted the PPS into the bilateral L1–5 pedicles of the lumbar model bone under fluoroscopic guidance, repeating this procedure twice with and without SG (groups SG and N-SG, respectively). Each vertebral body’s insertion time, radiation dose, and radiation exposure time were measured, and the deviation in screw trajectories was evaluated. Results: The groups SG and N-SG showed no significant difference in insertion time for the overall procedure and each operator. However, group SG had a significantly shorter radiation exposure time than group N-SG for the overall procedure (109.1 ± 43.5 seconds vs. 150.9 ± 38.7 seconds; p = 0.003) and operator A (100.0 ± 29.0 seconds vs. 157.9 ± 42.8 seconds; p = 0.003). The radiation dose was also significantly lower in group SG than in group N-SG for the overall procedure (1.3 ± 0.6 mGy vs. 1.7 ± 0.5 mGy; p = 0.023) and operator A (1.2 ± 0.4 mGy vs. 1.8 ± 0.5 mGy; p = 0.013). The 2 groups showed no significant difference in screw deviation. Conclusion The application of SG in fluoroscopic imaging for PPS insertion holds potential as a useful method for reducing radiation exposure.

Objective: To evaluate the preoperative and perioperative predictors of persistent leg numbness following lumbar fusion in patients aged ≥ 75 years. Methods: This single-center retrospective study examined 304 patients aged ≥ 75 years who underwent lumbar fusion for lumbar degenerative disease (102 men, 202 women; mean age, 79.2 [75–90] years). The visual analogue scale (VAS) score for leg numbness was examined preoperatively and at 2 years postoperatively. The persistent leg numbness group included patients with a 2-year postoperative VAS score for leg numbness ≥ 5 points. The demographic data were also reviewed. A multivariate stepwise logistic regression analysis was performed for variables with univariate analysis values of p < 0.2 on univariate analysis. Results: In total, 71 patients (23.4%) experienced persistent postoperative leg numbness. Multivariate logistic regression analysis revealed that a history of lumbar decompression, longer symptom duration, and a preoperative VAS score for leg numbness ≥ 5 points were associated with greater postoperative persistent leg numbness following lumbar fusion. In contrast, other factors, such as sex, body mass index, vertebral fracture, diabetes mellitus, depression, symptom duration, dural injury, operative time, and estimated blood loss, were not. Conclusion A history of preoperative lumbar decompression, longer symptom duration, and greater preoperative VAS scores for leg numbness were preoperative predictors of persistent postoperative leg numbness following lumbar fusion in older patients. Although lumbar fusion is expected to improve leg numbness, surgeons should consider the surgical history, duration, and preoperative numbness intensity and explain the potential postoperative persistent leg numbness in advance.

Objective: To elucidate the patient characteristics and outcomes of emergency surgery for spinal metastases and identify risk factors for emergency surgery. Methods: We prospectively analyzed 216 patients with spinal metastases who underwent palliative surgery from 2015 to 2020. The Eastern Cooperative Oncology Group performance status, Barthel index, EuroQol-5 dimension (EQ5D), and neurological function were assessed at surgery and at 1, 3, and 6 months postoperatively. Multivariate analysis was performed to identify risk factors for emergency surgery. Results: In total, 146 patients underwent nonemergency surgery and 70 patients underwent emergency surgery within 48 hours of diagnosis of a surgical indication. After propensity score matching, we compared 61 patients each who underwent nonemergency and emergency surgery. Regardless of matching, the median performance status and the mean Barthel index and EQ5D score showed a tendency toward worse outcomes in the emergency than nonemergency group both preoperatively and 1 month postoperatively, although the surgery greatly improved these values in both groups. The median survival time tended to be shorter in the emergency than nonemergency group. The multivariate analysis showed that lesions located at T3–10 (p = 0.002; odds ratio [OR], 2.92; 95% confidence interval [CI], 1.48–5.75) and Frankel grades A–C (p < 0.001; OR, 4.91; 95% CI, 2.45–9.86) were independent risk factors for emergency surgery. Conclusion Among patients with spinal metastases, preoperative and postoperative subjective health values and postoperative survival are poorer in emergency than nonemergency surgery. Close attention to patients with T3–10 metastases is required to avoid poor outcomes after emergency surgery.

Objective: Spine surgeons are often at risk of radiation exposure due to intraoperative fluoroscopy, leading to health concerns such as carcinogenesis. This is due to the increasing use of percutaneous pedicle screw (PPS) in spinal surgeries, resulting from the widespread adoption of minimally invasive spine stabilization. This study aimed to elucidate the effectiveness of smart glasses (SG) in PPS insertion under fluoroscopy. Methods: SG were used as an alternative screen for fluoroscopic images. Operators A (2-year experience in spine surgery) and B (9-year experience) inserted the PPS into the bilateral L1–5 pedicles of the lumbar model bone under fluoroscopic guidance, repeating this procedure twice with and without SG (groups SG and N-SG, respectively). Each vertebral body’s insertion time, radiation dose, and radiation exposure time were measured, and the deviation in screw trajectories was evaluated. Results: The groups SG and N-SG showed no significant difference in insertion time for the overall procedure and each operator. However, group SG had a significantly shorter radiation exposure time than group N-SG for the overall procedure (109.1 ± 43.5 seconds vs. 150.9 ± 38.7 seconds; p = 0.003) and operator A (100.0 ± 29.0 seconds vs. 157.9 ± 42.8 seconds; p = 0.003). The radiation dose was also significantly lower in group SG than in group N-SG for the overall procedure (1.3 ± 0.6 mGy vs. 1.7 ± 0.5 mGy; p = 0.023) and operator A (1.2 ± 0.4 mGy vs. 1.8 ± 0.5 mGy; p = 0.013). The 2 groups showed no significant difference in screw deviation. Conclusion The application of SG in fluoroscopic imaging for PPS insertion holds potential as a useful method for reducing radiation exposure.