Katsuya Nagashima

Dynamic Computed Tomography Myelography including the Prone Position as a Reliable Preoperative Imaging Method for Osteoporotic Vertebral Fracture with Neurological Deficits: A Preliminary Report of Three Cases

Aims: Delayed paralysis after osteoporotic vertebral fracture (OVF) in the elderly is caused by severe compression on the spinal cord or the cauda equina from the collapsed vertebral fragment that is retropulsed into the spinal canal. Patients with retropulsion of the vertebral fragment that occupies approximately 40% or more of the spinal canal likely develop delayed paralysis, suggesting that narrowing of 40% is the critical point. However, whether or not a neural decompression procedure during posterior instrumentation surgery, such as laminectomy should be performed during the surgery is still controversial. We performed dynamic computed tomography myelography (CTM) including the prone (surgical) position with OVF to investigate if the severity of spinal cord and cauda equina compression during the surgery could be estimated in advance. Materials and methods: The CTM was examined in 3 OVF patients (1 man and 2 women; mean age, 84 years) with neurological deficit in the supine and prone (surgical) positions to accurately estimate the necessity of decompression during surgery. Results: The spinal narrowing was 50% or higher in the supine position, but was less than 40% in the prone position in two patients (fracture at the T11 and L1 vertebrae), indicating that decompression was not necessary. Decompression was required in one patient (fracture at the L2 vertebra) with a high narrowing rate of 57% in the supine position and 56% in the prone position. Conclusion: Diagnostic imaging in the supine position alone will not help estimate the severity of intraoperative spinal cord or cauda equina compression because the degree of vertebral instability varies in each patient with OVF. ORIGINAL ARTICLE 1,4,5Assistant Professor, 2,3,6-8Spine Surgeon, 9Associate Professor, 10Professor 1,4-10Department of Orthopedic Surgery, University of Tsukuba Tsukuba, Ibaraki, Japan 2Department of Orthopedic Surgery, Kenpoku Medical Center Takahagi Kyodo Hospital, Takahagi, Ibaraki, Japan 3Department of Orthopedic Surgery, Ichihara Hospital, Tsukuba Ibaraki, Japan Corresponding Author: Toru Funayama, Assistant Professor Department of Orthopedic Surgery, University of Tsukuba Tsukuba, Ibaraki, Japan, Phone: +81298533219, e-mail: funatoru3 @gmail.com 10.5005/jp-journals-10039-1171

Visualization of walking speed variation-induced synchronized dynamic changes in lower limb joint angles and activity of trunk and lower limb muscles with a newly developed gait analysis system

Purpose: To evaluate a newly developed system for dynamic analysis of gait kinematics and muscle activity. Methods: We recruited 10 healthy men into this study. Analyses of three-dimensional motion and wireless surface electromyogram (EMG) were integrated to achieve synchronous measurement. The participants walked continuously for 10 min under two conditions: comfortable and quick pace. Outcome measures were joint angles of the lower limbs determined from reflective markers and myoelectric activity of trunk and lower limbs determined from EMG sensors, comparing comfortable and quick gait pace. Results: Lower limb joint angle was significantly greater at the quick pace (maximum flexion of the hip joint: 4.1°, maximum extension of hip joint: 2.3°, and maximum flexion of the knee joint while standing: 7.4°). The period of maximum flexion of the ankle joint during a walking cycle was 2.5% longer at a quick pace. EMG amplitudes of all trunk muscles significantly increased during the period of support by two legs (cervical paraspinal: 55.1%, latissimus dorsi: 31.3%, and erector spinae: 32.6%). EMG amplitudes of quadriceps, femoral biceps, and tibialis anterior increased significantly by 223%, 60.9%, and 67.4%, respectively, between the periods of heel contact and loading response. EMG amplitude of the gastrocnemius significantly increased by 102% during the heel-off period. Conclusion: Our gait analysis synchronizing three-dimensional motion and wireless surface EMG successfully visualized dynamic changes in lower limb joint angles and activity of trunk and lower limb muscles induced by various walking speeds.

The hybrid assistive limb (HAL) for Care Support successfully reduced lumbar load in repetitive lifting movements

Work-related low back pain is a serious socioeconomic problem. This study examined whether HAL for Care Support, which is a newly developed wearable robot, would decrease lumbar fatigue and improve lifting performance during repetitive lifting movements. Eighteen healthy volunteers (11 men, 7 women) performed repetitive stoop lifting movements of a cardboard box weighing 12 kg as many times as possible. The first lifting trial was executed without HAL for Care Support, and the second was with it. We evaluated the VAS of lumbar fatigue as the lumbar load and the number of lifts and the lifting time as lifting performance. Without HAL for Care Support, the mean VAS of lumbar fatigue, the number of lifts and lifting time were 68 mm, 60 and 230 s; with HAL for Care Support, they were 51 mm, 87 and 332 s, respectively. Both lifting performance measures were significantly improved by using HAL for Care Support (Fig. 2). A power analysis showed that there was sufficient statistical power for the VAS of lumbar fatigue (0.99), the number of lifts (0.92), and lifting time (0.93). All participants performed their repetitive lifting trials safely. There were no adverse events caused by using HAL for Care Support. In conclusion, the HAL for Care Support can decrease lumbar load and improve the lifting performance during repetitive stoop lifting movements in healthy adults.

Regenos spacers are not suitable for open-door laminoplasty because of serious adverse events caused by their insufficient mechanical strength

We used a newly developed, high-porosity unidirectional porous hydroxyapatite spacer (Regenos spacer, not approved by the FDA). The aim of the present study was to elucidate the effectiveness of Regenos laminar spacers for open-door type laminoplasty. The present study included 39 patients who underwent open-door type laminoplasty with Regenos spacers from April 2015 to December 2016 and were followed up for at least 6 months after surgery. We grafted 68 Regenos spacers in 39 patients. Pre- and postoperative neurological status of patients were evaluated using JOA score and recovery rate. Breakage of Regenos spacers, laminar closure, and bone-hydroxyapatite spacer bonding were assessed using 12-month postoperative sagittal and axial CT images. The average preoperative JOA score was 9.5 ± 3.2/17, and the average postoperative JOA score was 12.5 ± 2.9/17. JOA score recovery rate was 34 ± 41% at the latest follow-up visit. The bony fusion rate of the hinge sides was 87%. Breakage and deformity of implanted spacers was observed in 69% of patients and 59% of spacers with a CT sagittal view, and CT axial view at 12 months revealed fine cracks and collapse in 17 spacers in 14 patients. The average angle was -2.4 ± 4.8°, including 46 of 68 spacers showing a negative value, resulting in a rate of laminar reclosure of 35%. Postoperative CT demonstrated good bone bonding rate. Nevertheless, clinical results with low recovery rates were obtained with complications related to the use of Regenos spacers.

Unidirectional porous β-tricalcium phosphate induces bony fusion in lateral lumbar interbody fusion

Lateral lumbar interbody fusion (LLIF) often requires the use of allograft or artificial bone. We used β-tricalcium phosphate artificial bone with a porosity of 57% consisting of a novel unidirectional porous structure (Affinos®) in patients (5 male and 9 female) who underwent LLIF from August 2015 as a substitute for autologous bone. We evaluated 60 graft windows in the cages at 30 intervertebral levels. To evaluate interbody bony fusion, CT multi-planar reconstruction coronal and sagittal images obtained 1 year after surgery were assessed. Intra-cage bony fusion was observed in 39 of 60 graft windows and so total bony fusion rate was 65%. Intra-cage bony fusion was confirmed in 17 of 29 (58.6%) graft windows with autologous bone and 22 of 31 (70.9%) graft windows with Affinos®. There was no significant difference in the rate of bony fusion between autologous bone and Affinos® (p = 0.418). In conclusion, the rate of bony fusion using Affinos® in LLIF cages was not inferior to that using autologous bone graft. Affinos® is a candidate for graft material in LLIF surgery and further exploration is warranted.

Vertebral fracture after removing pedicle screws used for posterior lumbar interbody fusion: A case report

It is uncommon to remove pedicle screws after posterolateral lumbar interbody fusion (PLIF), and there are a few case reports of vertebral fracture involving holes remaining after screw removal. We report a case of the vertebral fracture after removing pedicle screws instrumented for PLIF. A 66-year-old woman with osteopenia, who underwent PLIF at L4-S1 10 years earlier, underwent PLIF at L3-L4 to correct adjacent-segment degeneration. We removed L5 and S1 pedicle screws, and inserted L3 pedicle screws. After surgery, she presented with severe progressive low back pain. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed an L5 body fracture involving the pedicle screw holes. Revision surgery, including posterolateral fusion from L3 to S2 alar iliac and L5 vertebroplasty, was performed. One year after the revision surgery, the patient remained pain-free and returned to normal activity. Possible reasons for instrumented vertebral body fracture after pedicle screw removal are decrease of vertebral mass, increased mechanical stress caused by PLIF at the adjacent segment, stress-shielding-related osteopenia, and spinal imbalance. Vertebral body fractures associated with spinal implant removal are rare, but possible, especially in elderly patients with osteopenia and osteoporosis.

Three-dimensional gait analysis reveals dynamic alignment change in a patient with dropped head syndrome: A case report

Dropped head syndrome (DHS) is a cervical kyphotic deformity caused by apparent weakness of the neck extensor muscles. We often encounter patients whose symptoms, including impaired forward vision and neck pain, deteriorate while walking. This is the first report of a case of dynamic spinal alignment change in a patient with DHS during walking using three-dimensional gait analysis. A 78-year-old Japanese woman complained of impaired forward vision and neck pain while walking. Her radiograph showed severe cervical kyphosis. C2-C7 SVA was +74 mm and C7-S1 SVA was -18.4 mm. The patient attempted to compensate to improve forward vision through lumbar hyperlordosis. We analyzed the gait motion of the patient by using three-dimensional (3D) motion and wireless surface electromyographic analysis systems to measure two systems synchronously. The patient walked continuously for as long as possible. We calculated dynamic SVA from the 3D motion analysis. Her head drop deformity gradually progressed and interfered with her forward vision while walking. Cervical SVA gradually increased from 75 to 85 mm. Thoracic SVA, Lumbar SVA and Whole spine SVA were initially decreased because of compensatory lumbar hyperlordosis, but ultimately increased, suggesting decompensation by the time she had finished walking. EMG activity of the bilateral trapezius muscles gradually reduced, which reflected the disturbance of maintaining her posture. Previous static evaluation could not prove the dynamic change of spinal alignment and EMG activity during walking. By introducing 3D gait analysis, we could evaluate dynamic spinal alignment of a patient with DHS.

Successful detection of postoperative improvement of dynamic sagittal balance with a newly developed three-dimensional gait motion analysis system in a patient with iatrogenic flatback syndrome: A case report

A 75-year-old Japanese woman with Parkinsons disease complained of lower back pain and gait disturbance because of iatrogenic flatback syndrome. The preoperative global spinal parameters were as follows: C7SVA, 168 mm; TK, 52°; LL, -0.8°; PI, 57°; PT, 55°; TPA, 60°. We performed 3D gait analysis using a VICON System and calculated the dynamic SVA. Preoperatively, her flexion deformity gradually progressed during walking. The dynamic parameters gradually increased as follows: thoracic SVA, 216-241 mm; lumbar SVA, 53-69 mm; spinal SVA, 270-311 mm. We performed two-stage corrective surgery. Her lower back pain and gait disturbance significantly improved. The postoperative global spinal parameters were as follows: C7SVA, 1 mm; TK, 47°; LL, 61°; PI, 52°; PT, 20°; TPA, 13°. Dynamic SVA detected by our 3D gait analysis using VICON were as follows: thoracic SVA, 128 mm; lumbar SVA, 4.9 mm; and spinal SVA, 133 mm. The postoperative dynamic SVA did not change during walking. This is the first report of a patient with iatrogenic flatback syndrome whose postoperative improvement of dynamic spinal sagittal alignment was successfully detected with a newly developed 3D gait analysis system that enabled us to analyze a dynamic change of SVA based on the patients actual walking with a continuous long-distance gait. Our 3D gait analysis has potential usefulness for evaluating postoperative sagittal balance for iatrogenic flatback syndrome.

Elderly patients in Japan are susceptible to cervical spine injury: a database search study

Background: The aim of the present study was to elucidate the prevalence of cervical spine injury and its age distribution, and the causes and mortality rate in Japan using the Japan Trauma Data Bank. Methods: Patients coded as having a cervical spine injury were extracted from the Japan Trauma Data Bank from 2004 to 2013, which consisted of a total of 152,722 patients. The number of patients, their age distribution and causes of injury were analyzed amongst the patients with Abbreviated Injury Score (AIS) coding associated with cervical spine injuries. Next, we extracted data for patients with an AIS coding of cervical spine injuries as a main disease, excluding patients with multiple trauma. We compared the mortality rate between aged and non-aged patients. Results: The total number of patients with an AIS code of cervical spine injuries was 12,116. The peak age range for cervical injury was 60–69 years. The most common causes of cervical spine injuries were falls from a height and traffic accidents. The number of patients with an AIS code of cervical spine injuries as a main disease was 8982. The total number of patients who died from a cervical spine injury was 668. Mortality rate tended to be higher in the older patients. Conclusions: The present results showed that the peak age range for cervical injury was 60–69 years. The mortality rate tended to be higher in patients over 70 years old.

The hybrid assisted limb (HAL) for Care Support, a motion assisting robot providing exoskeletal lumbar support, can potentially reduce lumbar load in repetitive snow-shoveling movements

An excessive lumbar load with snow-shoveling is a serious problem in snowfall areas. Various exoskeletal robots have been developed to reduce lumbar load in lifting work. However, few studies have reported the attempt of snow-shoveling work using exoskeletal robots. The purpose of the present study was to test the hypothesis that the HAL for Care Support robot would reduce lumbar load in repetitive snow-shoveling movements. Nine healthy male volunteers performed repetitive snow-shoveling movements outdoors in a snowfall area for as long as possible until they were fatigued. The snow-shoveling trial was performed under two conditions: with and without HAL for Care Support. Outcome measures were defined as the lumbar load assessed by the VAS of lumbar fatigue after the snow-shoveling trial and the snow-shoveling performance, including the number of scoops, and snow shoveling time and distance. The mean of VAS of lumbar fatigue, the number of scoops, and snow-shoveling time and distance without HAL for Care Support were 75.4 mm, 50.3, 145 s, and 9.6 m, while with HAL for Care Support were 39.8 mm, 144, 366 s, and 35.4 m. The reduction of lumbar fatigue and improvement of snow-shoveling performance using HAL for Care Support were statistically significant. There was no adverse event during snow-shoveling with HAL for Care Support. In conclusion, the HAL for Care Support can reduce lumbar load in repetitive snow-shoveling movements.