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OBJECTIVE The goal of this study was to clarify the clinical utility of paravertebral foramen screws (PVFSs) and to determine intraoperative indicators for appropriate screw placement during posterior cervical fusion surgery to improve its safety. METHODS The authors included data from 46 patients (29 men and 17 women, mean age 61.7 years) who underwent posterior cervical spine surgery with 94 PVFSs. Of the 94 PVFSs, 77 were used in C6, 9 in C3, 5 in C4, and 3 in C5. According to the cervical lateral radiographic view, the authors divided the 94 PVFSs into 3 groups as follows: a longer group, in which the tip of PVFS was located anteriorly from the line of the posterior wall of the vertebral body (> +0 mm); an intermediate group, in which the screw tip was located up to 2 mm posteriorly to the posterior wall of the vertebral body (–2 to 0 mm); and a shorter group, in which the screw tip was located more than 2 mm posteriorly (< –2 mm). The accuracy of screw placement was assessed using CT imaging in the axial plane, and the proportion of screws penetrating a vertebral foramen or a transverse foramen was compared between the 3 groups. Screw loosening was defined as a lucent zone around the screw evaluated on cervical radiography at 1 year after surgery. Complications related to PVFS insertion and revision surgery related to PVFS were evaluated. RESULTS The authors classified 25 PVFSs into the longer group, 43 into the intermediate group, and 26 into the shorter group. The proportion of screws penetrating a vertebral foramen was largest in the shorter group, and the proportion penetrating a transverse foramen was largest in the longer group. Screw loosening was confirmed for 3 of 94 PVFSs. One PVFS inserted in C6 unilaterally within a long construct from C2 to C7 showed loosening, but it did not cause clinical symptoms. Revision surgery was required for 2 PVFSs inserted in C3 bilaterally as the lower instrumented vertebra in occiput–cervical fusion because they pulled out. There was no neurovascular complication related to PVFS insertion. CONCLUSIONS PVFSs are useful for posterior cervical fusion surgery as alternative anchor screws, and the line of the posterior wall of the cervical body on lateral fluoroscopic images is a potential intraoperative reference to indicate an appropriate trajectory for PVFSs.

Recent studies have reported that confined high-intensity and diffuse low-intensity on sagittal T2-weighted magnetic resonance imaging (MRI) are distinctive features that are highly predictive of delayed union or nonunion on osteoporotic vertebral fracture (OVF). The objective of this study was to identify the characteristics of imaging findings predicting the risk for requiring surgical treatment in fresh OVF with poor prognostic features on MRI.We conducted a retrospective study of 74 patients (17 men and 57 women with a mean age of 81.1 years) of OVF with the poor prognostic MRI findings. We compared the imaging findings between the surgery group (16 patients) and the conservative group (58 patients): vertebral instability defined as the difference between the vertebral collapse ratio in dynamic X-rays, and the grade of posterior wall injury (Grade I, no spinal canal encroachment; Grade II,2 mm; Grade III, ≥2 mm) as well as the presence or absence of pedicle fracture (Grade I, none; Grade II, unilateral; Grade III, bilateral) on computed tomography.The mean vertebral instability was 24.0% ± 10.1% in the surgery group and 13.0% ± 7.8% in the conservative group, which was significantly different. Posterior wall injury in the surgery and conservative groups was Grade I in 0 and 29 cases, Grade II in 5 and 21 cases, and Grade III in 11 and 8 cases, respectively, constituting a significant difference. Pedicle fracture in the surgery and conservative groups was Grade I in 5 and 55 cases, Grade II in 6 and 2 cases, and Grade III in 5 and 1 case, respectively, also constituting a significant difference.The most high-risk OVF patients with poor prognostic MRI findings who required surgical treatment were those who exhibited greater vertebral instability as well as either more severe posterior wall injury or pedicle fracture.Retrospective clinical study.

We aimed to investigate the risk factors that affect vertebral deformity 6 months after osteoporotic vertebral fractures (OVFs) at the time of injury. From May 2017 to May 2020, 70 postmenopausal women with OVFs were evaluated for age; body mass index; number of previous OVFs; total 25-hydroxy vitamin D [25(OH)D] levels; posterior wall injury on computed tomography; cross-sectional area (CSA) of the psoas major, erector spinae, and multifidus; fat infiltration; vertebral instability (VI) upon admission; collapse rate (CR); and kyphotic angle (KA) at 6 months after injury. A multiple regression analysis was conducted to identify the risk factors for the CR and KA. The CR was correlated with posterior wall injury (r = 0.295, p = 0.022), 25(OH)D levels (r = − 0.367, p = 0.002), and VI (r = 0.307, p = 0.010). In the multiple regression analysis, the 25(OH)D levels (p = 0.032) and VI (p = 0.035) were significant risk factors for the CR at the 6-month follow-up. The KA was correlated with the 25(OH)D levels (r = − 0.262, p = 0.031) and VI (r = 0.298, p = 0.012). In the multiple regression analysis, the CSA of the psoas major (p = 0.011) and VI (p

The number of elderly people who undergo lumbar fusion surgery (LFS) has been increasing. Postoperative rehabilitation for them can be problematic due to lumbar stiffness. This is the first case report describing exercise therapy using the lumbar-type hybrid assistive limb (HAL) after multiple LFS in an elderly patient. An 83-year-old man underwent LFS at L4-S1. Additional fusion surgery at L2-3 for adjacent segment disease was performed 2 years after the primary surgery. Although the patient’s leg pain declined, he had severe locomotive dysfunction at 3 months after his final surgery. He started exercise therapy using the lumbar-type HAL including sit-to-stand training and squat training 4 months after his final surgery. He performed 3 sets of 20 sit-to-stand and 20 squat repetitions with adequate rests in between sets. The HAL training was safely conducted every day for 12 weeks without adverse event. Timed up and go test (TUG), 1-minute sit to stand test (1MSTS), one-leg stand test (OLST), and Berg balance scale (BBS) were assessed as locomotive function measurement. Before HAL therapy, TUG, 1MSTS, OLST, and BBS were 18.1 sec, 20 times, less than 1 sec, and 47, respectively. He could not walk without assistance. After the exercise therapy with the lumbar-type HAL, his locomotive function dramatically improved. TUG, 1MSTS, OLST, and BBS were 12.2 sec, 25 times, 3.9 sec, and 52, respectively. Moreover, the patient could walk 60 meters continuously without assistance. The unique characteristics of the lumbar-type HAL to prevent the lumbar overload and assist the voluntary hip joint motion during exercise therapy may be effective for this patient with lumbar stiffness after LFS. Sit-to-stand training and squat training using the lumbar-type HAL are promising options to improve locomotive function in elderly patients after LFS.

Background The penetrating end plate screw (PES) technique improved the fixation strength of the pedicle screw by penetrating the end plate in posterior fusion. The "double" PES, which is a trajectory that penetrates both the upper end plate of the corresponding vertebra and the lower end plate of the upper adjacent vertebral body, provides a stronger tricortical fixation but requires a stricter trajectory. The purpose of this study was to measure the cephalad angles from T7-L5 that would allow a safe trajectory for “double” PES. Methods We analyzed 1078 pedicles of 539 vertebral bodies of 50 consecutive cases (27 males and 23 females, mean age, 63.3 years) who underwent computed tomography (CT) myelography for evaluation of spinal disorders. The mean cephalad angle to obtain the double PES trajectory of each vertebra was examined, except for cases in which the appropriate trajectory would perforate the pedicles. Results The cephalad angle for the appropriate trajectory of “double” PES ranged from 23.4 to 37.6 degrees in the thoracic spine and 34.8 to 40.8 degrees in the lumbar spine. The ratio of pedicle perforation was significantly higher at T7 (16%), L4 (26%), and L5 (52%). Conclusions It is important to measure the optimal cephalad angle by preoperative computed tomography imaging according to the vertebral level. In L4 and L5, “double” PES should be avoided because it is often unsafe.

Standard shoulder rehabilitation procedures for patients with postoperative C5 palsy have not yet been established. We applied a wearable robot suit hybrid assistive limb (HAL) for a patient with postoperative C5 palsy and conducted shoulder abduction training with HAL. A 65-year-old woman was diagnosed with postoperative C5 palsy after undergoing cervical spine surgery. Five days after surgery, shoulder abduction training with HAL was initiated. The shoulder abduction angle and power and trapezius and deltoid activities were evaluated. Ten rehabilitation sessions were conducted until 82 days after surgery. Shoulder abduction training was safely and effectively performed from the first session. Her shoulder abduction angle and power improved at every session, and she could fully elevate her arm without any compensatory motion after the 10th session. Shoulder HAL training suppressed the muscular activity of the trapezius and activated that of the deltoid, especially in the earlier stages of rehabilitation. Moreover, it had an adjustment effect for obtaining normal shoulder motion, which might have promoted smoother arm elevation using errorless motor learning. These findings suggest that HAL is a useful tool for shoulder rehabilitation in patients with postoperative C5 palsy.

Cervical ossification of the posterior longitudinal ligament (OPLL) is a contributing factor to spinal cord injury or trauma-induced myelopathy in the elderly. To reduce the incidence of these traumas, it is essential to diagnose OPLL at an early stage and to educate patients how to prevent falls. We thus evaluated the ability of our convolutional neural network (CNN) to differentially diagnose cervical spondylosis and cervical OPLL. We enrolled 250 patients with cervical spondylosis, 250 patients with cervical OPLL, and 180 radiographically normal controls. We evaluated the ability of our CNN model to distinguish cervical spondylosis, cervical OPLL, and controls, and the diagnostic accuracy was compared to that of 5 board-certified spine surgeons. The accuracy, average recall, precision, and F1 score of the CNN for classification of lateral cervical spine radiographs were 0.86, 0.86, 0.87, and 0.87, respectively. The accuracy was higher for CNN compared to any expert spine surgeon, and was statistically equal to 4 of the 5 experts and significantly higher than that of 1 expert. We demonstrated that the performance of the CNN was equal or superior to that of spine surgeons.

Case report. To describe the first reported use of corrective surgery combined with C7 vertebral column resection (VCR) to treat an extremely rare case of severe, rigid cervical kyphotic deformity associated with synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome. Spinal lesions reportedly occur in 32–45% in SAPHO syndrome. However, bone and joint lesions are usually repaired such that severe joint destruction is rare. Therefore, there have been few reported cases of surgical treatment for spinal lesions. A 22-year-old woman had been diagnosed with cervical kyphotic deformity associated with SAPHO syndrome. She had difficulty looking upward. On radiography, the C4–C7 vertebral bodies were fused and exhibited severe rigid kyphotic deformity. Right convex scoliosis with a Cobb angle of 22° was apparent at C5–T2, and the C2–C7 angle of kyphosis was 75°. Corrective three-stage surgery was carried out from the anterior, posterior, and anterior, with C7 VCR. The C2–T1 angle improved to 21° and the patient was capable of looking up. At present, 2 years postoperatively, complete bony fusion has been achieved. Her cervical spine function and quality of life were markedly improved. Only a very limited number of patients have a deformity sufficiently severe that VCR of cervical vertebra is required, but as this is the technique that provides the greatest multiplanar alignment correction, its choice in the present case was appropriate. IV.

Although diffuse idiopathic skeletal hyperostosis (DISH) is generally asymptomatic, in rare cases it involves multiple segments and can present with intervertebral pseudoarthrosis which requires treatment. We report a case of a 47-year-old female patient with intervertebral pseudoarthrosis and severe dynamic instability in the L4–5 intervertebral disc due to DISH and provide a brief review of literature. The patient developed severe lower back pain and intermittent claudication due to the instability in the only mobile part between multiple fused vertebrae from C7 to L4 and fusion segment from L5 to the ilium. We performed long-range posterior spinal and two-stage 360° fusion with L4–5 lateral interbody fusion. After the surgery the pain and intermittent claudication were improved and bony fusion was successful. Reports of intervertebral pseudoarthrosis in DISH with no history of trauma are extremely rare. We have only been able to find 5 cases. Compared to the previous reports, the present case describes a youngest patient, first case of female, and had the longest fusion due to DISH. Therefore, the patient required long-range fusion from T10 to the iliac bone in order to achieve adequate stabilization. Moreover, the present case is the first example of choosing a lateral interbody fusion, which provides even more robust consolidation.

Although adjacent segmental disease after posterior thoracic fusion surgery is rare, thoracic myelopathy due to ossification of the yellow ligament in the lower thoracic spine could develop because of mechanical stress when the lower instrumented vertebra has been set to the middle thoracic spine during the initial surgery. We report an extremely rare case of distal adjacent segmental disease after posterior cervical-middle thoracic fusion surgery requiring reoperation after exhibiting thoracic myelopathy due to ossification of the yellow ligament in the lower thoracic spine. An obese 53-year-old man with diabetes had undergone C3-6 laminoplasty and C7-T8 posterior decompression plus fusion due to ossification of the posterior longitudinal ligament at C5-T5. Although the short-term clinical course after the initial surgery was good, symptoms of myelopathy reappeared because of the ossification of the yellow ligament that developed at T9-11 with local flexibility. Thus, reoperation with fusion extension surgery was needed 1 year and 6 months after the initial surgery. Altogether, we recommend careful monitoring of the postoperative clinical progression and, if necessary, reoperation at the earliest.

Study Design: Prospective experimental study in humans.Purpose: To determine whether the hybrid assistive limb (HAL) for Care Support can reduce lumbar load during a patient transfer.Overview of Literature: The prevalence of work-related low back pain (LBP) among nurses is high. In particular, transferring patients poses a high risk for LBP due to the large lumbar load. Attempts to reduce the lumbar load are crucial to avoid the risk of LBP. Therefore, we investigated the effects of the HAL for Care Support.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.

PurposeTo investigate whether preoperative dynamic spinal alignment that worsened during gait as detected by three-dimensional (3D) gait analysis can be a predictive factor for proximal junctional kyphosis (PJK) after corrective surgery for adult spinal deformity (ASD) with a minimum 1-year follow-up.MethodWe included 27 patients with ASD who underwent 3D gait analysis before corrective surgery and had >1-year follow-up. Dynamic spinal alignment parameters were obtained using a Nexus motion capture system (Vicon, Oxford, UK) with reflective markers. Spinal alignment was assessed in each region and pelvic alignment was assessed with surface markers. Patients were asked to walk for as long as possible around an oval walkway. We obtained the averaged dynamic parameters in the final lap and compared them between patients with PJK(+) and those with PJK(–).ResultsPJK occurred in 7 patients (26%). Preoperative angle between the thoracic spine and the pelvis was larger in patients with PJK(+) than in those with PJK(–) (32.3 ± 8.1 vs 18.7 ± 13.5, P = 0.020) with sufficient sample size. Multiple logistic regression analysis identified the angle between the thoracic spine and pelvis as an independent risk for PJK.ConclusionPreoperative thoracic kyphosis exacerbated by gait as determined in 3D gait analysis is a preoperative independent risk factor of PJK in patients undergoing ASD corrective surgery.

C5 palsy is a serious complication that may occur after cervical spine surgery; however, standard procedures for shoulder rehabilitation for patients with postoperative C5 palsy have not yet been established. We used a wearable robot suit Hybrid Assistive Limb (HAL) in a patient with delayed recovery after postoperative C5 palsy and conducted shoulder abduction training with the HAL. A 62-year-old man presented with weakness in his left deltoid muscle 2 days after cervical spine surgery. He experienced great difficulty in elevating his left arm and was diagnosed with postoperative C5 palsy. Seven months after surgery, shoulder abduction training with a HAL was initiated. In total, 23 sessions of shoulder HAL rehabilitation were conducted until 26 months after surgery. His shoulder abduction angle and power improved at every HAL session, and he was able to fully elevate his arm without any compensatory movement after the 23rd session, suggesting that the HAL is a useful tool for shoulder rehabilitation in patients with postoperative C5 palsy. We employed shoulder HAL training for a patient with delayed recovery from postoperative C5 palsy and achieved complete restoration of shoulder function. We believe that the HAL-based training corrected the erroneous motion pattern of his paralyzed shoulder and promoted errorless motor learning for recovery. Our collective experience suggests that shoulder HAL training could be an effective therapeutic tool for patients with postoperative C5 palsy.

Objective This study aimed to analyze the neurological symptoms caused by thoracolumbar lesions according to their distance from where the spinal cord terminates for a better description of epiconus syndrome. Methods We retrospectively reviewed cases of patients with neurological symptoms caused by a thoracolumbar lesion in a single institute. Neurological symptoms were analyzed according to the distance from the proximal end of the lesion to where the spinal cord terminates using MRI or CT myelograms. The symptoms were classified into epiconus syndrome, thoracic myelopathy, and conus medullaris syndrome. The distance was described regarding the length of a vertebral body (VB). Results We included 19 patients in this series. The spinal cord terminates were at the lower third of the L1 vertebra most frequently (32%) in the range of T12 to L2 vertebra. The border between thoracic myelopathy and epiconus syndrome was 2VB proximal from where the spinal cord terminates, and that between epiconus syndrome and conus medullaris syndrome was 1VB. Mean disease duration until symptoms changed was 2.4 months in epiconus syndrome, while it was 25 months in thoracic myelopathy, and 10.3 months in conus medullaris syndrome. Conclusion Epiconus syndrome is caused by lesion 1-2VB proximal to where the spinal cord terminates. This study may provide further helpful information for clinical practice in the treatment of epiconus syndrome.

Background In general, the diagnosis of pedicle screw (PS) loosening is evaluated qualitatively based on the presence of a radiolucent area around the implant wider than 1 mm on plain radiographs and computed tomography (CT). Digital tomosynthesis is a novel imaging technology that can acquire reconstructed tomographic images of patients in different postures with relatively low radiation. In this study, PS loosening is evaluated quantitatively by measuring the PS displacement angle in the vertebrae using digital tomosynthesis. Methods We evaluated 41 patients who underwent posterior spinal fusion surgery using PS. The 72 pedicle screws at the cranial end of the fused segments were evaluated. The patients were divided in two groups, one with PS loosening (7 patients, 12 screws) and the other without PS loosening (34 patients, 60 screws), based on conventional CT findings. All patients underwent tomosynthesis in two different postures during a single CT session. Results The displacement angles of the PS in patients in a lying position and in a standing position were measured using selected slices of the same cross-sectional view from digital tomosynthesis. The displacement angle was significantly greater in the PS loosening group (5.7°) than in the group without PS loosening (0.6°) (p Conclusions This new method using digital tomosynthesis has the potential to aid diagnosis of PS loosening quantitatively and more accurately than conventional evaluations.

This study aimed to investigate whether fat infiltration in lumbar paravertebral muscles assessed by magnetic resonance imaging (MRI) could be related to dynamic sagittal spino-pelvic balance during gait in adult spinal deformity (ASD). This is a retrospective analysis of 28 patients with ASD. The fat infiltration rate of lumbar erector spinae muscles, multifidus muscles and psoas major muscles was measured by T2 weighted axial MRI at L1-2 and L4-5. Dynamic sagittal spinal and pelvic angles during gait were evaluated using 3D motion analysis. The correlation between fat infiltration rate of those muscles with variations in dynamic kinematic variables while walking and static radiological parameters was analyzed. Spinal kyphosis and pelvic anteversion significantly increased during gait. Fat infiltration rate of erector spinae muscles at L1-2 was positively correlated with thoracic kyphosis (r = 0.392, p = 0.039) and pelvic tilt (r = 0.415, p = 0.028). Increase of spinal kyphosis during walking was positively correlated with fat infiltration rate of erector spinae muscles both at L1-2 (r = 0.394, p = 0.038) and L4-5 (r = 0.428, p = 0.023). Qualitative evaluation of lumbar erector spinae muscles assessed by fat infiltration rate has the potential to reflect dynamic spino-pelvic balance during gait.

We report a case of cardiac arrest, which occurred during C1 laminectomy for irreducible atlantoaxial subluxation, with return of spontaneous circulation (ROSC) upon interruption of the laminectomy. A 60-year-old woman with rheumatoid arthritis presented with neck pain, bilateral finger numbness, and bladder-rectal disturbance. Simple radiograph images showed that the atlantodental interval (ADI) was enlarged to 8 mm, and magnetic resonance imaging revealed severe spinal stenosis at C1. She was diagnosed with cervical spondylotic myelopathy due to atlantoaxial subluxation. Cardiac arrest occurred twice during the C1 laminectomy and occipito-cervical fusion (Occ-C3), and ROSC occurred without any treatment. There was no postoperative worsening of neurological symptoms, and the improvement of sensory and motor palsy was favorable. The pathogenic mechanism was presumed to be trigeminocardiac reflex. Cardiac arrest during upper cervical spine surgery is an important intraoperative complication of which operators should be made aware.

Objectives To describe the novel technique of continuous local antibiotic perfusion (CLAP) for a surgical site infection (SSI) after instrumented spinal surgery. Methods CLAP was applied to 4 continuous patients at our institution who developed SSI after instrumented spinal surgery. Results All 4 patients were successfully treated and the infection was controlled. The implant was retained in all patients. The duration of CLAP ranged from 2 to 3 weeks. The blood level of the antibiotic used (gentamicin) at 1 week after the initiation of CLAP did not increase in any patient. No other adverse events occurred in any patient. Dramatic improvements in laboratory parameters, including the white blood cell (WBC) counts and C-reactive protein (CRP) levels were seen in every patient at 1 week after the initiation of CLAP. Conclusions CLAP controlled the infection without severe adverse events in all 4 patients, and the implants were retained. Despite its cost and the discomfort of patients, CLAP may become an option for the treatment of SSIs after instrumented spinal surgery. A large number of case series are needed to verify the efficacy of CLAP for patients with SSIs after instrumented spinal surgery.

Conventional fluoroscopic guidance can provide enough information to precisely insert an occipital screw in ordinary cases. However, the occipital screw creates a potential risk of dural venous sinus injury or thrombosis. In some cases, with dural sinus variation, surgeons must especially be cautious to avoid its injury. We present a rare case of proper occipital screw placement using a navigation system for a pathological odontoid fracture with a high risk of dural venous sinus injury because of anatomical variations in the transverse and occipital sinuses. A 60-year-old man who underwent thyroidectomy at the age of 37 years for thyroid carcinoma developed acute neck pain and quadriparesis due to falling out of bed. He urgently underwent closed reduction and temporary immobilization with a halo-vest for a pathological odontoid fracture and atlantoaxial dislocation. Preoperative contrast-enhanced CT showed an absent right transverse sinus and a prominent occipital sinus as variations of the dural venous sinuses. Occipito-C7 fusion surgery was performed without intraoperative active venous bleeding or postoperative brain disorder by using a navigation system for the occipital screw placement to avoid injury to the dural sinus. Postoperative computed tomography showed bi-cortical occipital screw placement avoiding the prominent occipital sinus. The patient's postoperative course was uneventful. In this case, although rigid occipito-cervical fixation using bi-cortical occipital screws was needed for the pathological odontoid fracture, the variation of the occipital sinus created a high risk of injury during occipital screw placement with conventional fluoroscopic guidance. There is an anatomical variation of the dural venous sinuses between individuals. Prominent occipital sinus injury may notably cause fatal complications such as massive bleeding or occlusion. Thus, we safely inserted the occipital screws using a navigation system that enabled us to avoid occipital venous sinus injury. Occipital screw placement with a navigation system can be a better option to prevent dural venous sinus injury in cases where there is variation in the dural venous sinuses, such as with a prominent occipital venous sinus.

The symptoms of lumbar foraminal stenosis are often exacerbated when the patient is upright. Lumbar pathological conditions related to clinical symptoms such as disc herniation, foraminal stenosis, and instability of the lumbar spine are often exacerbated when the patient is upright and hidden when the patient is supine. Lumbar radiculopathy is usually diagnosed by MRI. However, it is difficult to detect the compression of nerve roots while the patient is upright using conventional MRI when the patient is supine. Dynamic digital tomosynthesis radiculography (DTRG) while the patient is upright detects pathological changes of the lumbar nerve root while the patient is upright. We report cases of symptomatic lumbar foraminal stenosis which were diagnosed by using digital tomosynthesis radiculography with the patient in an upright position. Three patients with history of unilateral leg pain which was exacerbated when they were upright underwent selective nerve root block and DTRG in both prone and upright positions. All patients were relieved of the leg pain after selective nerve root block. DTRG with the patient in an upright position showed better exacerbation of nerve root compression than while the patient was prone in all cases. DTRG with the patient in prone and upright positions is useful to detect compression of nerve roots hidden while MRI is conducted with the patient supine. DTRG is helpful to diagnose lumbar foraminal stenosis which is exacerbated while the patient is upright.

We used a newly developed, high-porosity unidirectional porous hydroxyapatite spacer (Regenos spacer, not approved by the FDA). To assess the short-term bone bonding capacity of Regenos spacer used in a double-door laminoplasty, including displacement, deformation, and absorption after implantation. Fifty patients underwent a double-door laminoplasty using Regenos spacers, with computed tomography (CT) images obtained at 2-4 weeks and 6-12 months, post-surgery, in 30 patients. Bone bonding rate, amount of displacement, and the incidence of deformation and absorption were evaluated from the early and late postoperative CT images. Bone bonding rate for Regenos spacers, using our modified classification, was 48.9% at 6 months, post- surgery, and 67.0% at 12 months. The change in anterior-posterior diameter of the spinal canal (ΔH) was significantly greater for Regenos spacers than for autologous bone spacers (p 0.05). There was no difference in the change in angle between the vertebral arch and the posterior wall of the vertebral body (ΔR) between the Regenos and autologous bone spacers. Deformation was identified in 21.3% (10/47). Though, no evidence of breakage along their long axis was identified among these 10 cases on axial CT images with passable clinical results. Regenos spacers lowered the risk of early dislocation after implantation and facilitated bone bonding due to infiltration of surrounding tissue. However, the deformation and absorption was observed at high rates because of their insufficient mechanical strength, we need to require a longer term follow-up to more clearly evaluate their adverse impact in clinically.

Charcot spinal arthropathy (CSA) is a rare spinal disorder presenting neuropathic osteoarthropathy of facet joints leading to progressive destruction. After L4-5 PLIF, a 63-year-old woman with Parkinson's disease (PD) underwent L3-4 and L5-S1 PLIF for primary adjacent segment disease caused by degenerative change, which was found as facet joint osteophytes and a vacuum disc phenomenon with endplate sclerosis. However, her postural disorder from PD deteriorated, and strong opioid analgesics were administered for severe recurring low back pain. Anterior subluxation at L2-3 occurred because of destructive secondary adjacent segment disease, which was found as destruction of the endplate and the facet without degenerative change, and formation of paravertebral osteophytes and fluid collection in the intervertebral space. The appearance on imaging met that for neuroarthropathic change, which was previously reported as CSA. L2-3 PLIF following extension of posterior fusion to T10 was additionally performed, and the postoperative course was uneventful with symptomatic improvement. In this case, the important finding was in the different appearance of the disease between adjacent segments on imaging. It is possible that deterioration of PD and administration of the analgesics inhibited deep pain sensation, and concentration of mechanical stress in the proximal adjacent segment by the long lever arm because of extension of the fusion level resulted in neuroarthropathic change of the facets in the secondary adjacent segments. The pathophysiology of association of CSA and PD remains unknown. However, we recommend vigilance for destructive neuroarthropathic facet change as CSA after spinal surgery in patients with severe PD.

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.

Thoracic disc herniation is less common than lumbar and cervical disc herniations. It is usually accompanied by severe myelopathy, which often leads to surgery. Because the thoracic spine is less mobile, thoracic disc herniation is considered to be minimally affected by dynamic spine factors in cases with myelopathy. We experienced a case of thoracic disc herniation (T4/5 and T6/7) characterized by posture-related dynamic changes in neurological symptoms; that is, numbness extending from the trunk to the entire lower limbs was deteriorated in the standing and sitting positions, was relieved in the supine position, and disappeared in the prone position. In addition, the patient reported dysuria with a delay when attempting to urinate in the standing position. Computed tomographic myelography revealed diffuse idiopathic skeletal hyperostosis extending from T3 to T11, and the kyphosis angles at T1 to T11 levels were 68 degrees in the half-sitting position and 58 degrees in the prone position, showing posture-related changes. The patient underwent the posterior fusion in the prone position, by which symptoms disappeared, without undergoing disc herniotomy or laminectomy, and favorable outcomes were achieved. Thoracic disc herniation with marked posture-related neurological symptoms is extremely rare. Here we report a case presentation and literature review of pathophysiology observed in our patient. Keywords: Thoracic disc herniation, Posture-related symptom, Posterior fusion, Flexion myelopathy

Background With a rapidly aging population in Japan, locomotive syndrome is becoming an increasingly serious social problem. Exercise therapy using the lumbar type HAL, which is a wearable robot suit that can assist voluntary hip joint motion, would be expected to cause some beneficial effects for people with locomotive syndrome. The purpose of this study was to assess whether the deterioration of low back pain and any other adverse events would occur following HAL exercise therapy. Moreover, the changes of motor ability variables were evaluated. Methods We enrolled 33 participants (16 men, 17 women) with locomotive syndrome in this study. They received exercise training (sit-to-stand, lumbar flexion-extension, and gait training) with HAL (in total 12 sessions). We assessed the change of low back pain (lumbar VAS). More than 50% and 25 mm increase compared to baseline was defined as adverse events. One-leg standing time (OLST), 10-m walking test (10MWT), Timed Up and Go test (TUG), 1-min sit-to-stand test (1MSTS), FIM mobility scores and EQ-5D were measured. Results Of the 33 participants, 32 (16 men, 16 women) (97.0%) completed all 12 exercise training sessions using the lumbar type HAL. One woman aged 82 years withdrew because of right upper limb pain after the second session regardless of the use of HAL. There was no participant who had deterioration of low back pain. Any other adverse events including external injuries and/or falling, skin disorders, uncontrollable cardiovascular or respiratory disorders, and other health disorders directly related to this exercise therapy did not occur. Several outcome measures of motion ability including OLST, TUG and 1MSTS, EQ VAS and lumbar pain improved significantly after this HAL training. Conclusions Almost all patients with locomotive syndrome completed this exercise training protocol without any adverse events related to HAL. Furthermore, balance function variables including OLST, TUG and 1MSTS improved after this HAL exercise therapy even though mobility function variables including 10MWT and FIM mobility scores did not show any significant change. These findings suggest that the exercise therapy using the lumbar type HAL would be one of the options for the intervention in locomotive syndrome.

Background Several authors have reported favorable results in low back pain (LBP) for patients with lumbar disc herniation (LDH) treated with discectomy. However, detailed changes over time in the characteristics and location of LBP before and after discectomy for LDH remain unclear. To clarify these points, we conducted an observational study to determine the detailed characteristics and location of LBP before and after discectomy for LDH, using a detailed visual analog scale (VAS) bilaterally. Methods We included 65 patients with LDH treated by discectomy in this study. A detailed VAS for LBP was administered with the patient under 3 different conditions: in motion, standing, and sitting. Bilateral VAS was also administered (affected versus opposite side) for LBP, lower extremity pain (LEP), and lower extremity numbness (LEN). The Oswestry Disability Index (ODI) was used to quantify clinical status. Changes over time in these VAS and ODI were investigated. Pfirrmann grading and Modic change as seen by magnetic resonance imaging (MRI) were reviewed before and 1 year after discectomy to determine disc and endplate condition. Results Before surgery, LBP on the affected side while the patients were in motion was significantly higher than LBP while they were sitting (p = 0.025). This increased LBP on the affected side in motion was improved significantly after discectomy (p p = 0.015). At 1 year following discectomy, residual LBP while sitting was significantly greater in cases showing changes in Pfirrmann grade (p = 0.002) or Modic type (p = 0.025). Conclusions Improvement of LBP on the affected side while the patient is in motion suggests that radicular LBP is improved following discectomy by nerve root decompression. Furthermore, residual LBP may reflect increased load and pressure on the disc and endplate in the sitting position.

Occipito-cervical fusion surgery may cause dysphagia due to inadequate occipito-cervical alignment. However, little is known about any other mechanisms behind postoperative dysphagia. We present a rare case of severe sarcopenic dysphagia despite appropriate occipito-cervical alignment after occipito-cervical fusion surgery. An 85-year-old man who presented with high-cervical myelopathy due to a retro-odontoid pseudotumor underwent occipito-cervical fusion surgery and developed severe dysphagia immediately after the surgery. Swallowing videoendoscopy revealed stagnation of thick fluid at the larynx. Oral intake was prohibited and swallowing rehabilitation was performed. Subsequently, he showed a gradual improvement in swallowing function. He was allowed to start oral intake in the fourth week after surgery and was able to swallow solid foods in the sixth week after surgery. In this case, several parameters of occipito-cervical alignment such as the occipito-C2 angle (O-C2 angle), swallowing line (S-line), C2-C7 angle, and pharyngeal inlet angle, which are recognized as predictors of postoperative dysphagia after occipito-cervical fusion surgery, were adequate to prevent postoperative dysphagia. However, the patient had sarcopenia and cervical hyperlordosis to compensate for thoracic hyperkyphosis, which induces the hypertonicity of hyoid muscles. These findings led to a diagnosis of sarcopenic dysphagia after surgical invasion. Sarcopenic dysphagia is considered to be associated with skeletal and swallowing muscle weakness, apart from thinness, malnutrition, and surgical invasion. Elderly patients with sarcopenia may present with sarcopenic dysphagia because of surgical invasion after occipito-cervical fusion surgery. In such cases, it is important not only to control intraoperative occipito-cervical alignment but also to evaluate preoperative swallowing function.

Objective: To report a case of anterior longitudinal ligament (ALL) injury that was not noticeable during lateral lumbar interbody fusion and was disclosed after posterior corrective fusion surgery. Case presentation: After performing lateral lumbar interbody fusion followed by posterior corrective fusion surgery, we observed an anterior longitudinal ligament rupture that required additional surgery. Postoperative pain in the left lower limb and muscle weakness due to nerve traction appeared, but this was improved by stabilization between the vertebral bodies. Conclusion: Unidentified anterior longitudinal ligament rupture can result in unexpected local lordosis during posterior surgery, possibly related to lower extremity palsy. Therefore, checking for possible rupture during and after anterior surgery is important. If the ALL damage is disclosed before posterior surgery, the proper surgical strategy for the posterior surgery must be considered.

Objective: Whether or not emergent decompression/fusion surgery for paralysis caused by metastatic spinal tumors of unknown origin improves patient neurological outcome and survival remains unclear. This study aimed to evaluate the clinical outcomes of emergent decompression/fusion surgery for paralysis caused by spinal tumors of unknown or not previously diagnosed origin. Patients and Methods: Data from the medical records of 11 patients with spinal tumors of unknown origin (study group) were compared with those of 15 patients with metastatic spinal tumors of known origin (control group). The outcome measures were postoperative performance status, motor function evaluated with the Frankel grade, and actual survival after surgery as compared with the estimated survival calculated using the Tokuhashi score. χ2 analyses were performed to evaluate differences between the groups. Results: The mean performance status was 3.6 preoperatively, which improved to 2.9 postoperatively (P

The symptoms of lumbar radiculopathy, in particular foraminal stenosis, often exacerbated when the patient is upright. However, it is difficult to detect the compression of nerve roots while the patient is upright using conventional MRI. In this study, we analyzed the compression of lumbar nerve roots using dynamic digital tomosynthesis radiculography (DTRG) in patients diagnosed with lumbar radiculopathy. And we determined the relationship between leg pain and nerve compression while the patients are either prone or upright. We evaluated 30 patients with unilateral leg pain diagnosed as lumbar radiculopathy by physical examination and MRI. The patients were divided in two groups, one with foraminal stenosis (17 patients) and the other with canal stenosis (13 patients), based on MRI findings. All patients underwent DTRG to determine the diameter of their nerve roots in the foramen while prone and upright. Pain while prone or upright was assessed using a 100-point visual analogue scale (VAS) questionnaire. The VAS for leg pain while upright was significantly higher in the foraminal stenosis group (58 ± 24.7) than it was in the canal stenosis group (19.6 ± 13.2; p = 0.0002)). The nerve root diameter while prone or upright was significantly smaller in the foraminal stenosis group (1.2 ± 0.2 mm) than it was in the canal stenosis group (0.2 ± 0.1 mm; p 0.0001). DTRG has the potential to visualize nerve compression while the patient is upright to reveal the relevance of foraminal stenosis to clinical findings. DTRG is useful for diagnosis of lumbar foraminal stenosis.

Disorders of the central nervous system sometimes cause severe sensory motor paralysis accompanied by gait impairment. Recently, there are several reports on the effectiveness of robot-assisted gait training for patients experiencing these issues. The purpose of this case report was to assess the neuromechanical effect of a wearable robot suit HAL (Hybrid Assistive Limb) during post-operative gait training in a patient with gait impairment due to compressive myelopathy caused by ossification of the posterior longitudinal ligament (OPLL). For this purpose, we compared lower limb muscular activities while the patient was walking with and without the robot through a course of treatment sessions by (i) gait phase-dependent muscle usage analysis, (ii) muscle synergy analysis, and (iii) muscle network analysis. The results show (i) enhanced activity of the extensor muscles for weight-bearing in the initial sessions by using HAL and reduced knee extensor and increased hip extensor activations for achieving larger steps and faster gait in the later sessions; (ii) involvement of a greater number of synergies during walking with HAL than without HAL; and (iii) modulated muscle network property during walking with HAL remaining until the next HAL session. The patient's gait was improved after completing HAL sessions, acquiring close to normal joint profile with greater range of joint movement, faster walking speed, and larger step length. We discuss that the muscular activity modulation during walking with HAL suggests altered control of the muscles by the central nervous system during post-operative walking. Activity-dependent sensorimotor augmentation by HAL is discussed in the context of recovery of gait control by the central nervous system. The relationship between the altered control and the achieved gait recovery requires further investigation.

Surgical indication of posterior decompression and fusion (PDF) for cervical OPLL in mainly based on K-line, which is defined as that which connects the midpoints of the spinal canal at C2 and C7 in a plain lateral radiogram of the cervical spine. We defined K-line (+) as cases where the peak of ossification foci does not exceed the K-line and K-line (−) as cases where the peak of ossification foci exceeds the K-line. Previous reports revealed that laminoplasty produces a poor outcome in K-line (−) OPLL. One of the surgical options is PDF.

Several reports have described the coexistence of spina bifida occulta (SBO) and spondylolysis, but the majority of defects occur at L5. No report has described the coexistence of SBO and spondylolysis at the thoracolumbar junction. We report a case of SBO with spondylolysis at L1, presenting cauda equine syndrome. A 37-year-old man presented with a gait disorder as a result of bilateral motor weakness of the lower extremities. A plain radiograph showed local kyphosis at L1-2 as a result of severe degenerative change and wedging of the vertebral body at L1. Magnetic resonance imaging (MRI) revealed degenerative disc changes and severe canal stenosis at L1-2. Computed tomography (CT) revealed SBO and spondylolysis at L1. He was diagnosed with cauda equina syndrome related to SBO and spondylolysis at L1. Posterior interbody fusion and decompression at L1-2 were performed. After surgery, his muscle power recovered to normal strength. The possible mechanisms in this case are the strain on anterior elements as a result of disruption of the posterior elements due to SBO and spondylolysis. The coexistence of SBO and spondylolysis at the thoracolumbar junction might induce at-risk status of increased strain to the anterior elements that may cause cauda equina syndrome.

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.

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.

Dropped head syndrome (DHS) is characterized by a chin-on-chest deformity, which can severely interfere with forward vision and impair activities of daily living. A standardized treatment strategy for DHS has not been established. To our knowledge, this is the first case report describing the efficacy of gait training using a hybrid assistive limb (HAL) for DHS. A 75-year-old man showed apparent head drop in a standing position, resulting in passively reducible chin-on-chest deformity. A radiograph image showed apparent cervical kyphosis. Center of gravity of the head (CGH)–C7 SVA was +115 mm, CL was −40°, and T1S 39°. The patient underwent a treatment program using HAL, in which gait training was mainly performed, 60 min a day, 5 days a week for 2 weeks (10 sessions). After 2–3 sessions, dropped head started to attenuate. At the end of 10 sessions, the patient was able to walk with normal posture and radiograph images showed cervical kyphosis dramatically decreased because of HAL training. CGH–C7 SVA was 42 mm, CL was −1.7°, and T1S was 30°. Three months’ outpatient follow-up revealed a slight deterioration of cervical alignment. However, the patient was able to maintain a better cervical alignment than before HAL training and keep walking with forward vision. There were no complications in any HAL treatment session. In conclusion, gait training using HAL is an option for treatment of DHS in addition to previously reported neck extensor muscle training.

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.

After spine fusion surgery, it is difficult to evaluate the spinal canal and nerve roots using magnetic resonance imaging (MRI) because of metallic implant-related artifacts. Digital tomosynthesis is a new radiographic technique that can acquire tomographic images with reduced metallic artifact effects compared with MRI. We report a case demonstrating the visualization of nerve roots nearby metallic implants using dynamic tomosynthesis-radiculography (DTRG) after spinal fusion surgery. A 77-year-old man, who 3 years earlier underwent spine fusion surgery at L3–L5, presented complaining of newly-onset low back pain and radicular symptoms in the right fifth lumbar (L5) nerve root area. His symptoms were exacerbated when he stood upright. We suspected right L5 nerve root radiculopathy, but MRI could not depict any lesion of the nerve root because of metallic implant-related artifacts. We performed DTRG at the right L5 nerve root with the patient in both prone and upright positions. The right L5 nerve root was detected clearly, and nerve root compression at the foramina when the patient was upright was exacerbated more than when the patient was in a prone position. DTRG is helpful to diagnose lumbar foraminal stenosis nearby metallic implants after spine fusion surgery.

We report an extremely rare case showing a fifth cervical spine (C5) level pure motor cervical spinal cord injury (SCI). A 55-year-old-man lost consciousness and fell into a bathtub. Immediately after regaining consciousness, the patient had right arm drop alone. He was referred to our department for investigation of right arm drop 4 months later. Neurological examination revealed motor weakness of the right deltoid muscle. MRI of the cervical spine revealed a C3-4 level central disc herniation compressing the spinal cord. An electromyogram study revealed bilateral neurogenic discharges in the deltoid, supraspinatus and infraspinatus muscles. We diagnosed a C5 segmental pure motor SCI. We chose conservative therapy for the present patient. At the latest follow-up visit, the patient showed modest recovery of motor weakness. Although it is unusual, this case illustrates the possibility that C5 segmental pure motor palsy can occur as one of the manifestations of cervical SCI.

Background: Percutaneous endoscopic discectomy (PED) has been reported to be an effective procedure and minimally invasive surgical therapy for various spinal pathologies. Objective: To evaluate the clinical outcome of patients with pyogenic spondylitis who were treated with PED. Methods: Twenty-four patients with pyogenic spondylitis who underwent PED were evaluated for medical history, level of the affected intervertebral space, mode of onset, plain radiographs, epidural or psoas abscesses on MRI, results of blood and intraoperative sample cultures, preoperative C-reactive protein (CRP) level, time until postoperative CRP normalization (CRP < 0.3), and any additional surgery. Patients who underwent additional surgery and showed uncontrollable inflammation were considered to have “failed” PED for pyogenic spondylitis. To elucidate the factors that were significantly associated with a failure of PED for pyogenic spondylitis, statistical analyses were conducted by univariate analysis. Results: Control of inflammation was achieved in 19 of 24 patients (76%) after PED for pyogenic spondylitis. The remaining five patients failed to achieve infection control by PED. One such patient was not able to control the infection after PED, and another patient developed an epidural abscess 2 weeks after PED. Remaining three “failed” patients had exacerbations of their infections during the postoperative course and required additional surgery. Univariate analyses demonstrated that diabetes mellitus (DM; p = 0.05), hemodialysis due to DM-induced renal failure ( p = 0.02), concomitant malignant disease ( p = 0.09), and acute onset ( p = 0.05) were possibly correlated with PED failure. Stepwise logistic regression analysis revealed that hemodialysis due to DM-induced renal failure was an independent factor associated with PED failure ( p = 0.03). Conclusions: PED might be considered as one of the alternative therapeutic options before invasive radical surgeries for pyogenic spondylitis after failure of standard conservative therapy. Even by less invasive PED, pyogenic spondylitis patients with DM-hemodialysis showed poor outcome.

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.

The aim of this study was to elucidate the bone regeneration-inducing capability of Affinos®, a newly developed, high-porosity unidirectional porous β-TCP artificial bone. We compared the ability of Affinos® and OSferion®, a commercially available β-TCP product, to induce bone regeneration following implantation into bony defects left after fibula harvesting for spinal fusion surgery. Study subjects underwent surgery to harvest non-vascularized fibula grafts for spinal fusion surgery and were implanted with either Affinos® (19 patients) or OSferion® (15 patients, control group) at the defect site. The minimal and mean follow up periods were 6 and 11 months after surgery, respectively. X-rays of the lower leg taken 1–2 weeks after surgery and at the final follow-up visit were used to evaluate fibular-β-TCP continuity and fibula defect filling ratio. There was no significant difference in radiographic continuity in the fibula between the two groups. The fibula defect filling ratio for the Affinos® group decreased from 0.94 ± 0.17 at 1–2 weeks to 0.77 ± 0.14 at 10 months. For the OSferion® control group, the fibula defect filling ratio decreased from 0.94 ± 0.14 at 1–2 weeks to 0.52 ± 0.27 at final follow-up. The Affinos® group showed a significantly higher fibula defect filling ratio compared to that for the OSferion® group (p = 0.003). These results indicate that Affinos® has slow absorption rates and significant defect filling activity compared with OSferion®. Thus, Affinos® could be a suitable substitute to fill bony defects induced by fibula harvesting for spinal reconstruction surgery.

To determine dynamic changes of spinopelvic alignment while walking using a three-dimensional (3D) gait motion analysis in adult spinal deformity (ASD) patients. This study included 20 ASD patients. The 3D gait motion analysis (Vicon) was performed during continuous walking to their limit. Dynamic parameters were obtained using reflective markers on the spinous processes, which were segmented into thoracic (T-), lumbar (L-), and whole spine (S-), sagittal spinal distance (SVA) and coronal one (CVA), sagittal spinal angle to the vertical axis (SA) and coronal one (CA), sagittal pelvic angle to the horizontal axis (P-SA) and coronal (P-CA), and thoracic limited spinal angle to the pelvic angle (T-P SA) and lumbar one (L-P SA). The dynamic variables at the final lap were compared with those at the first lap of an oval walkway. Spinal kyphotic deformity deteriorated significantly. As for pelvic angle, the mean P-SA parameters (first lap/final lap) were 3.2°/5.2°. Anteversion of pelvic sagittal angle increased significantly after continuous walking to their limit. In particular, regarding limited spinal angle to the pelvic angle, the mean T-P SA parameters were 30.5°/36.2° and L-P SA parameters were 6.4°/6.8°. Thoracic kyphotic angle increased significantly, but lumbar kyphotic angle did not change. Decrease of thoracic kyphosis and pelvic retroversion has been recognized as a compensation for ASD on standing radiograph. Our 3D gait motion analysis to determine spinal balance found thoracic kyphosis and pelvic anteversion increased significantly in patients with ASD after continuous walking to the limit of their endurance until they were fatigued, indicating a failure of compensation for ASD. These slides can be retrieved under Electronic Supplementary Material.

Background A high-riding vertebral artery (HRVA) is an intraosseous anomaly that narrows the trajectory for C2 pedicle screws. The prevalence of a HRVA is high in patients who need surgery at the craniovertebral junction, but reports about HRVAs in subaxial cervical spine disorders are limited. We sought to determine the prevalence of HRVAs among patients with subaxial cervical spine disorders to elucidate the potential risk for VA injury in subaxial cervical spine surgery. Methods We included 215 patients, 94 were with a main lesion from C3 to C7 (subaxial group) and 121 were with a main lesion from T1 to L5 (thoracolumbar group). A HRVA was defined as a maximum C2 pedicle diameter of Results The patients in the subaxial group were younger than those in the thoracolumbar group, but their sex and BMI did not differ significantly between the 2 groups. The mean osteoarthritis grade of the C1-2 facet joints of patients in the subaxial group was significantly higher than that in those in the thoracolumbar group. A HRVA was found in 26 patients of 94 (27.7 %) in the subaxial group and in 19 of 121 (15.7 %) in the thoracolumbar group. The prevalence of a HRVA in the subaxial group was significantly higher and osteoarthritis of C1-2 facet joints correlated significantly with a HRVA. Conclusions The prevalence of a HRVA in patients with subaxial cervical spine disorders is higher than in those without and osteoarthritis of the C1-2 facet joints is correlated with a HRVA.

Background and Objectives: Dropped head syndrome (DHS) is characterized by apparent neck extensor muscle weakness and difficulty in extending the neck to raise the head against gravity. DHS affects forward vision and eating behavior, and hence impairs quality of life. However, standardized treatment of DHS has not yet been established. The purpose of this preliminary study is to seek for a possibility of effective non-surgical, conservative treatment for DHS, by applying a robotic treatment. Materials and Methods: A wearable exoskeleton type robot suit hybrid assistive limb (HAL) was applied to three patients with DHS. A course of HAL treatment included 10 sessions of gait training using HAL. One session lasted about an hour. Case 1 completed the course twice, the first time in two weeks (one session per day) and second time in 10 months (one session per month). Case 2 and Case 3 completed the course once in 10 weeks (one session per week) and in 6 months (one session per 2.5 weeks), respectively. Immediate and lasting effects of HAL on the reduction of cervical sagittal vertical alignment (SVA) during gait was evaluated using a motion capture system. Results: Case 1 showed improvement of cervical alignment during gait after the HAL courses of both different frequencies. Case 2 did not show improvement of cervical alignment during gait. Case 3 showed improvement of cervical kyphosis but not of cervical sagittal alignment during gait. Conclusions: The results of the preliminary study suggest that gait training using HAL may be an effective option of conservative treatment for a part of DHS patients. They also suggest that a lack of immediate effects on the cervical alignment and a lack of ability to perform compensatory trunk motion may indicate a non-responding patient. Generalization of the results requires further research with more cases.

The coexistence of lumbar intervertebral disc (IVD) herniation and cauda equina schwannoma in symptomatic patients is uncommon. We experienced a case with a surgically treated cauda equina schwannoma with concomitant lumbar IVD herniation (L2/L3); both were relatively small but presented with painful symptoms in combination. A 45-year old man complained of low back pain and right anterior thigh pain six months prior to surgery. He underwent conservative treatment; however, his pain suddenly worsened three months before surgery, with abnormal sensations and pain in his right buttock and posterior thigh. A magnetic resonance imaging (MRI) scan revealed an L2/L3 disc herniation extruding to the center of the lumbar spinal canal and compressing the thecal sac. Incidentally, an intrathecal tumor was suspected, and enhanced MRI revealed a round tumor measuring 10-mm in diameter at the L2/L3 intervertebral level, which was uniformly enhanced by gadolinium chelate, radiologically diagnosed as a schwannoma. Microscopic discectomy and tumor resection were performed and the patient's symptoms disappeared immediately. Schwannoma is generally slow-growing, and usually asymptomatic when the tumor size is small. Therefore, we suspected that the tumor occasionally impinged on the left L3 root with L2/3 IVD herniation, leading to acute worsening of the patient's symptoms. Altogether, in case of tumor in patients undergoing conservative treatment for cauda equina schwannoma, we should consider that symptoms can acutely worsen with the occurrence of lumbar IVD herniation.

The aim of this study was to investigate the incidence and characteristics of implant failure in posterior cervical long-segment fusion surgery. We retrospectively reviewed 51 cases of posterior cervical long-segment fusion surgery that used pedicle screws, lateral mass screws, or laminar screws. The cranial end of the fusion was C2 or C3, and the caudal end of the fusion was C7 or T1. All patients were observed with CT scans at 6 months postoperatively. We evaluated the loosening and breakage of the implanted screws or rods. In the 51 patients, 257 pedicle screws, 9 laminar screws and 233 lateral mass screws were placed. Implant failure occurred in 25 patients (49.0%). Screw loosening was found in 42 screws (8.4%). Screw breakage occurred in 6 (1.2%) screws. The implant failures were particularly observed in both ends of the fusion level. When C7 was the end of the lower instrumented level, the incidence was 40% without C6 pedicle screws, 33% with unilateral C6 pedicle screws, and 0% with bilateral C6 pedicle screws. The present study revealed that the incidence of implant failures of the screws in long-segment posterior cervical fusion surgery was higher, especially in the caudal end of the fusion levels. In cases where C7 was the lowest instrumented vertebra, buttress screw insertion to C6 is recommended to avoid implant failure of C7 pedicle screws.

A 75-year-old Japanese woman with Parkinson’s 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 patient’s actual walking with a continuous long-distance gait. Our 3D gait analysis has potential usefulness for evaluating postoperative sagittal balance for iatrogenic flatback syndrome.