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Introduction: Few studies have assessed the minimum clinically important difference (MCID) of each Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) domain. This study assessed MCIDs of JOABPEQ in patients with lumbar spine disease by generation. Methods: We evaluated the JOABPEQ score of 805 consecutive patients with lumbar spine disease undergoing posterior surgery preoperatively and 1 year postoperatively. MCIDs of each JOABPEQ domain were determined using anchor- and distribution-based methods according to age. A question based on the concept of a health transition item was used as the anchor for the MCID decision. Results: Overall, MCIDs of the JOABPEQ were 28.6 and 27.3 points for pain-related disorder and gait disturbance, respectively. The MCID for the lumbar spine dysfunction domain did not reach 0.6 over the area under the curve. Regarding the differences among generations, MCIDs of pain-related disorder and gait disturbance domains differed slightly between the elderly and middle-aged. The psychological disorder domain did not reflect clinically meaningful changes in the elderly. MCIDs of the social life disturbance domain decreased with age. Conclusions: Focusing on achieving the ideal responsiveness of patient-reported outcomes across generations, MCIDs of the pain-related disorder and gait disturbance domains may be valuable for patients, regardless of age, when adopting the JOABPEQ for patients with lumbar spine disease undergoing surgery. This study only evaluated cases that underwent posterior lumbar surgery. Future research will necessitate conducting surveys concerning the outcomes of various treatments for lumbar spine disease.

In recent years, heavy rainfall disasters have occurred frequently in Japan, which increases the importance for private companies to take flood countermeasures to prepare improved business continuity plans (BCPs). Although river authorities have published flood hazard maps for design rainfall and probable maximum rainfall in Japan, hazard information for floods with other return periods is also required for the target business facilities to make cost-effective plans and investment decisions based on flood risk assessment. In order to overcome the situation where public flood hazard maps do not provide enough information for risk-based business continuity planning, we developed a method to provide tailored flood risk information for a business site based on a series of flood inundation simulations for rainfall scenarios with various return periods in the expected inundation area of the Tama River, Tokyo, Japan. Calculated results showed that the inundation characteristics highly depend on the topographic features of the flood plain, suggesting the importance of assessment at a respective business site. We also present an example of the application of the proposed method of simulation results in designing the BCP.

Study Design Level 3 retrospective cohort case-control study. Purpose This study aimed to investigate the risk factors for distal junctional kyphosis (DJK) caused by osteoporotic vertebral fractures following spinal reconstruction surgery, with a focus on the sagittal stable vertebra. Overview of Literature Despite the rarity of reports on DJK in this setting, DJK was reported to reduce when the lower instrumented vertebra (LIV) was extended to the sagittal stable vertebra in the posterior corrective fixation for Scheuermann’s disease. Methods This study included 46 patients who underwent spinal reconstruction surgery for thoracolumbar osteoporotic vertebral fractures and kyphosis and were followed up for 1 year postoperatively. DJK was defined as an advanced kyphosis angle >10° between the LIV and one lower vertebra. The patients were divided into groups with and without DJK. The risk factors of the two groups, such as patient background, surgery-related factors, radiographic parameters, and clinical outcomes, were analyzed. Results The DJK and non-DJK groups included 14 and 32 patients, respectively, without significant differences in patient background. Those with instability in the distal adjacent LIV disc had a significantly higher risk of DJK occurrence (28.6% vs. 3.2%, p=0.027). DJK occurrence significantly increased in those with the sagittal stable vertebra not included in the fixation range (57.1% vs. 18.8%, p=0.020). Other preoperative radiographic parameters were not significantly different. Instability in the distal adjacent LIV disc (adjusted odds ratio, 14.50; p=0.029) and the exclusion of the sagittal stable vertebra from the fixation range (adjusted odds ratio, 5.29; p=0.020) were significant risk factors for DJK occurrence. Conclusions Regarding spinal reconstruction surgery in patients with osteoporotic vertebral fractures, instability in the distal adjacent LIV disc and the exclusion of the sagittal stable vertebra from the fixation range were risk factors for DJK occurrence in the short term.

Abstract The bulk density of grains from a celestial body is a fundamental property related to its composition and structure, contributing to the understanding of its evolutionary history. In this study, we provide the bulk density of 637 grains returned from the C-type near-Earth asteroid 162173 Ryugu. This is the largest number of grains to date for the curation activity, corresponding to 38 wt.% of the total returned samples (approximately 5.4 g). Although several densities of the Ryugu grains were reported, the volume estimation of some samples showed uncertainties. Therefore, we applied a new volume estimation model calibrated by X-ray micro-computed tomography (XCT) to the Ryugu grains to more accurately estimate their bulk density. The obtained average bulk density of 637 Ryugu grains was 1.79 ± 0.31 g/cm3 (1σ variation) for weights of 0.5‒100 mg (sub-mm ‒to 10 mm) irrespective of their 3D shapes characterized by three axial length ratios, considered to be a representative of the returned samples. The bulk density distributions of the grains in Chambers A and C were statistically distinguishable, with mean values of 1.81 ± 0.30 and 1.76 ± 0.33 g/cm3 (1σ variations), respectively. Despite the small difference, bulk density may have differed by sampling site. The obtained average bulk density value of A + C samples was almost the same as that of 16 Ryugu grains estimated based on CT scanned data, and was consistent with the densities of CI chondrites (1.57–1.91 g/cm3). The axial ratios of the grains in Chambers A and C were similar and those of the 724 returned samples and the flying particles ejected during the sampling operations were also similar, suggesting that relatively small Ryugu materials (mm‒cm in size) are similar in shape. The minor difference between the Rygu grains and flying particles could be attributed to events such as scraping during sampling operations and transportation. Graphical Abstract

Abstract Developing a cleanroom and clean chambers (CCs) for Hayabusa2 returned samples has been discussed with the committee for Hayabusa2 sample curation facility since 2015. One major difference from the specifications of the CCs used for Itokawa samples is that a part of samples was decided to be handled and preserved in vacuum to avoid terrestrial nitrogen contamination with organics or unknown materials that might easily react with the samples. Thus, the CCs for Hayabusa2 samples were divided into two CCs for vacuum processes and three CCs for purified nitrogen conditions. The cleanroom was built in summer 2017, while the CCs were installed in the summer of 2018. After the installation of the CCs, instruments for initial descriptions, sample containers, handling tools for powder and particle samples, and jigs to assist handling samples were developed in parallel with functional checks and repeated rehearsals between the fall of 2018 and the fall of 2020. The curatorial works on Hayabusa2-retuned samples were conducted as previously planned. Simultaneously, contaminations and influences of inorganics, organics, microbial, and magnetic constructs have been assessed to evaluate their potential effects on the analysis of the returned samples. Additionally, the tools used to touch samples directly have been demagnetized to avoid sample magnetization during their handling and the tool magnetization was measured before and after their usages. The series of developments and experiences from the curatorial works of Hayabusa2-returned samples represent valuable implications for future sample return missions. Graphical Abstract

Osteoporotic vertebral fractures (OVFs) can hinder physical motor function, daily activities, and the quality of life in elderly patients when treated conservatively. Vertebral augmentation, which includes vertebroplasty and balloon kyphoplasty, is a commonly used procedure for OVFs. However, there have been reports of complications. Although serious complications are rare, there have been instances of adjacent vertebral fractures, cement dislocation, and insufficient pain relief due to cement failure, sometimes necessitating revision surgery. This narrative review discusses the common risks associated with vertebral augmentation for OVFs, such as cement leakage and adjacent vertebral fractures, and highlights the risk of revision surgery. The pooled incidence of revision surgery was 0.04 (0.02–0.06). The risks for revision are reported as follows: female sex, advanced age, diabetes mellitus, cerebrovascular disease, dementia, blindness or low vision, hypertension, hyperlipidemia, split type fracture, large angular motion, and large endplate deficit. Various treatment strategies exist for OVFs, but they remain a subject of controversy. Current literature underscores the lack of substantial evidence to guide treatment strategies based on the risks of vertebral augmentation. In cases with a high risk of failure, other surgeries and conservative treatments should also be considered as treatment options.

Abstract The JAXA Astromaterials Science Research Group developed a web-based database system for the Hayabusa2-returned samples from C-type asteroid Ryugu. The Ryugu Sample Database System database (RS-DBS) is designed as an online catalog for users of wide scientific communities to choose their preferred samples and propose the sample loan through the JAXA Ryugu Sample Announcement of Opportunity. Ryugu samples can be sorted and given identification numbers as individual particles larger than 1 mm and aggregate samples consisting of less than 1 mm particle through the Phase1 curation (i.e., the initial description). The RS-DBS lists all samples with analytical data such as a microscopy image, size, mass, spectroscopic data, and shape model obtained by the initial description at the JAXA curation facility. The list also includes research results conducted by previous projects (i.e., the Hayabusa2 initial analysis team and Phase2 curation teams). The RS-DBS, built with open-source technologies, archives the data securely and long-term on the Data Archives and Transmission System (DARTS) at ISAS/JAXA. Graphical Abstract

Abstract Surface and subsurface materials of C-type near-Earth asteroid 162173 Ryugu were collected and successfully returned to the Earth in the Hayabusa2 mission. Fourier Transform Infrared Spectroscopy (FTIR) has been conducted to characterize these returned samples as one of the initial descriptions in a non-destructive manner under a purified nitrogen condition without terrestrial contamination. We selected the individual grains and aggregate samples that were not severely influenced by the reflection of incident beam at the sapphire dish and analyzed their reflectance spectra using the primary component analysis (PCA). The result indicates that Ryugu returned samples are highly homogeneous with only a little heterogeneity. The average spectrum of the main PCA group is represented by four absorption bands at 2.7, 3.05, 3.4, and 3.95 μm. The spectral feature is consistent with that obtained from bulk FTIR measurements, indicating potential presence of hydroxyl, organics, and carbonates. Rarely observed types of grains with unique spectra are categorized into three groups: significantly high reflectance, carbonates, and hydroxyl compounds with broad OH absorption. Graphical Abstract

Introduction: The coronavirus disease 2019 (COVID-19) pandemic has greatly changed the lifestyles of individuals due to the need to prevent disease spread. Globally, governments have enforced various policies, including travel bans, quarantine, home confinement, and lockdowns, as safety measures. Consequently, the frequency of individuals going out has decreased. This survey aimed to assess how decreasing the frequency of going out due to the COVID-19 pandemic impacts patients with spinal disorders. Methods: This multicenter cross-sectional questionnaire survey included patients who visited four private spine clinics for any symptoms. Participants completed questionnaires pre- and post-pandemic that assessed the following topics: frequency of leaving home, exercise habits, locomotive syndrome, and health-related quality of life (HRQOL). Patients were divided into decreased and non-decreased frequency of going out groups, according to observed changes in their frequencies of leaving home. Both groups were statistically compared using univariate and multivariate logistic regression analyses to identify factors associated with the frequency of going out. Results: Among 855 patients, 160 (18.7%; the decreased group) reported that they went out less frequently, and 695 (81.3%; the non-decreased group) reported that they left home equally frequently post- versus pre-pandemic. Multivariate analyses showed that exercise habits significantly decreased (adjusted odds ratio (aOR) = 2.67, p = 0.004), the incidence of locomotive syndrome significantly increased (aOR = 2.86, p = 0.012), and HRQOL significantly deteriorated (aOR = 4.14, p < 0.001) in the decreased group compared to the non-decreased group. Conclusions: Restrictions regarding leaving home due to the COVID-19 pandemic significantly decreased exercise frequency, increased the occurrence of locomotive syndrome, and were associated with deterioration of HRQOL in patients with spine disorders. It may be beneficial for spine surgeons to encourage patients with spinal disorders to leave home at a frequency similar to what they did pre-pandemic while avoiding crowded areas, despite the presence of the COVID-19 pandemic.

Study Design A retrospective case control study. Purpose The purpose of this study was to compare the surgical outcomes of multilevel lateral lumbar interbody fusion (LIF) and multilevel posterior lumbar interbody fusion (PLIF) in the surgical treatment of adult spinal deformity (ASD) and to evaluate the sagittal plane correction by combining LIF with posterior-column osteotomy (PCO). Overview of Literature The surgical outcomes between multilevel LIF and multilevel PLIF in ASD patients remain unclear. Methods We retrospectively reviewed 31 ASD patients who underwent multilevel LIF combined with PCO (LIF group, n=14) or multilevel PLIF (PLIF group, n=17) and with a minimum 2-year follow-up. In the comparison between LIF and PLIF groups, their mean age at surgery was 69.4 vs. 61.8 years while the mean follow-up period was 29.2 vs. 59.3 months. We evaluated the transition of pelvic incidence–lumbar lordosis (PI–LL) and disc angle (DA) in the LIF group, in fulcrum backward bending (FBB), after LIF and after posterior spinal fusion (PSF) with PCO. The spinopelvic radiographic parameters were compared between LIF and PLIF groups. Results Compared with the PLIF group, the LIF group had less blood loss and comparable surgical outcomes with respect to radiographic data, health-related quality of life scores and surgical time. In the LIF group, the mean DA and PI–LL were unchanged after LIF (DA, 5.8°; PI–LL, 15°) compared with the values using FBB (DA, 4.3°; PI–LL, 15°) and improved significantly after PSF with PCO (DA, 8.1°; PI–LL, 0°). Conclusions In the surgical treatment of ASD, multilevel LIF is less invasive than multilevel PLIF and combination of LIF and PCO would be necessary for optimal sagittal correction in patients with rigid deformity.

Background The coronavirus disease 2019 (COVID-19) pandemic has affected people in various ways, including restricting their mobility and depriving them of exercise opportunities. Such circumstances can trigger locomotor deterioration and impairment, which is known as locomotive syndrome. The purpose of this study was to investigate the incidence of locomotive syndrome in the pandemic and to identify its risk factors. Methods: This was a multicenter questionnaire survey performed between 1 November 2020 and 31 December 2020 in Japan. Patients who visited the orthopedics clinic were asked to answer a questionnaire about their symptoms, exercise habits, and locomotor function at two time points, namely, pre-pandemic and post-second wave (current). The incidence of locomotive syndrome in the COVID-19 pandemic was investigated. Additionally, multiple logistic regression analysis was used to identify the risk factors for developing locomotive syndrome during the pandemic. Results: A total of 2829 patients were enrolled in this study (average age: 61.1 ± 17.1 years; 1532 women). The prevalence of locomotive syndrome was 30% pre-pandemic, which increased significantly to 50% intra-pandemic. Among the patients with no symptoms of locomotive syndrome, 30% developed it in the wake of the pandemic. In the multinomial logistic regression analysis, older age, deteriorated or newly occurring symptoms of musculoskeletal disorders, complaints about the spine or hip/knee joints, and no or decreased exercise habits were independent risk factors for developing locomotive syndrome. Conclusions: The prevalence of locomotive syndrome in patients with musculoskeletal disorders has increased during the COVID-19 pandemic. In addition to age, locomotor symptoms, especially spine or hip/knee joint complaints, and exercise habits were associated with the development of locomotive syndrome. Although the control of infection is a priority, the treatment of musculoskeletal disorders and ensuring exercise habits are also essential issues to address during a pandemic such as COVID-19.

Study Design Retrospective case series. Purpose To evaluate surgical outcomes and effectiveness of an autogenic rib graft for upper cervical fixation in pediatric patients. Overview of Literature Autogenic bone grafts have long been considered the ‘gold standard’ bone source for posterior cervical fusion in pediatric patients. However, there are some unsolved problems associated with donor-site morbidity and amount of bone grafting. Methods We studied five consecutive pediatric patients who underwent atlantoaxial fixation or occipitocervical fixation (OCF) using an autogenic rib graft with at least 2 years of follow-up (mean age, 9.8 years; mean follow-up period, 73.0 months). Two patients underwent OCF without screw-rod constructs and three patients with screw-rod constructs. Autogenic rib grafts were used in all patients. We evaluated the surgical outcomes including radiographic parameter, bony union, and perioperative complications. Results The atlantoaxial interval (ADI) was corrected from 11.6 to 6.0 mm, and the C1–2 angle was corrected −14.8° to 7.8°. The C2–7 angle was reduced from 31° to 9° spontaneously. Two patients with OCF required revision surgery due to loss of correction. Patients did not experience any complication associated with the donor sites (rib bone grafts). Six months postoperation X-rays clearly showed regeneration of the rib at the donor sites. Bony fusion was achieved in all patients; however, bony fusion occurred more slowly in patients without screw-rod constructs compared with patients with screw-rod constructs. Bone regeneration of the rib was observed in all patients with no complications at the donor site. Conclusions Autogenic rib grafts have advantages of potential bone regeneration, high fusion rate, and low donor-site morbidity. In addition, a screw-rod construct provides better bony fusion in pediatric patients with OCF and atlantoaxial fixation.

Abstract Background There are only a few published case reports of irreducible Galeazzi fracture-dislocation, and patients in these studies had undergone reduction by open surgical methods. Arthroscopy for the distal radioulnar joint of the wrist joint has recently been used for wrist pathology. We aim to describe the surgical procedure involved in arthroscopic reduction of irreducible Galeazzi fracture-dislocation and clinical outcome and review the literature. Case presentation We present the case of a 26-year-old man, a professional athlete, who sustained Galeazzi fracture-dislocation during a bicycle race. The distal radioulnar joint was irreducible because the fragment of the ulnar styloid was trapped between the sigmoid notch and ulnar head after a doctor had previously reduced it manually. Operative treatment was performed using a 30° oblique, 1.9-mm arthroscope. Reduction of the fragment of the ulnar styloid was achieved using distal radioulnar joint arthroscopy. The metaphyseal and intra-articular fracture of the radius and the fragment of the ulnar styloid were fixed using a volar locking plate and tension band wiring technique, respectively. A daily injection of parathyroid hormone and low-intensity pulsed ultrasound were used postoperatively. The patient was asymptomatic and returned to the preinjury level of athletic activity 2 months postoperatively, and bone union of the radius and ulna was achieved without distal radioulnar joint instability 15 months postoperatively. Conclusions Less invasive reduction of the dorsal anatomical structure enabled our patient to return early to sports. We consider arthroscopic reduction to be superior to the open surgical method in terms of evaluating interpositions; additionally, arthroscopic reduction is minimally invasive and does not need immobilization because it does not cause significant damage to the dorsal capsule and subsheath of the extensor carpi ulnaris, which comprise the triangular fibrocartilage complex.

Background and Objectives: Although percutaneous laser disc decompression (PLDD) is one of the common treatment methods for patients with lumbar disc herniation (LDH), the recurrence of LDH after PLDD is estimated at 4–5%. This study compares the preoperative clinical data and clinical outcomes of patients who underwent primary microendoscopic discectomy (MED) or MED following PLDD. Materials and Methods: We retrospectively analyzed 2678 patients who underwent MED for LDH. The PLDD group included patients with previous PLDD history at the same level of LDH, and a matched control group was created using propensity score matching for age, sex, and body mass index. Preoperative data, preoperative radiographic findings, and surgical data of the groups were compared. To compare postoperative changes in clinical scores between the groups, a mixed-effect model was used. Results: As a result, 42 patients (1.6%) had previously undergone PLDD, and a control group with 42 patients were created. The disc degeneration severity was not significantly different between the groups. However, Modic changes were more frequent in the PLDD group than in the matched control group (p = 0.028). There were no significant differences in dural adhesion rate or surgery-related complications including dural injury, length of stay, and recurrence rate of LDH after surgery. In addition, the improvement of clinical scores did not significantly differ between the two groups (p = 0.112, 0.913, respectively). Conclusions: We concluded that patients with recurrent LDH after PLDD have advanced endplate degeneration, which may reflect endplate injury from a previous PLDD. However, a previous history of PLDD does not have a negative impact on the clinical result of MED.