Daisaku Takeuchi

Role of Ethnicity in Alignment Compensation: Propensity Matched Analysis of Differential Compensatory Mechanism Recruitment Patterns for Sagittal Malalignment in 288 Asd Patients From Japan, Korea, and United States

Study Design. Retrospective review of adult spinal deformity patients in a multiethnic database. Objective. To investigate the role of ethnicity on recruitment of compensatory mechanisms for sagittal spinal deformity. Summary of Background Data. While the impacts of age, sex, and pelvic morphology on the ability to compensate for sagittal malalignment have been investigated, the role of ethnicity in compensatory mechanism recruitment is poorly understood. Methods. Patients from USA (85% Caucasian) >25 y/o were propensity matched by age, sex, and pelvic incidence with patients from Korea and Japan. Only primary patients or those with existing fusion below T12 were retained for analysis. Groups were subclassified by deformity severity (aligned: sagittal vertical axis (SVA) <50 mm; moderate malalignment: SVA 50–100 mm; severe malalignment: SVA >100 mm). Radiographic measurements including pelvic retroversion, thoracic kyphosis, loss of lumbar lordosis (PI minus LL), cervical lordosis, and cervical SVA were compared between the groups. Results. There were 288 patients (96 each in USA, KOR, JPN), with similar age (64–67 yr) and PI (49–53°). USA had smaller pelvic incidence minus lumbar lordosis in every alignment group (P <0.05). In moderate malalignment, JPN had more pelvic retroversion than USA (30° vs. 20°), and KOR had more thoracic hypokyphosis than USA (15 vs. 31°). In severe malalignment, JPN had more pelvic retroversion than USA (39° vs. 27°), and KOR had more thoracic hypokyphosis than USA (15° vs. 31°). KOR had smaller cSVA than USA in both aligned (11 vs. 27 mm) and moderate (19 vs. 31 mm) malalignment. In severe malalignment, KOR had less cervical lordosis (13° KOR vs. 15° USA vs. 27° JPN). All differences with P <0.05. Conclusion. Compensation for sagittal is ethnicity dependent. Korean patients favor thoracic compensation via hypokyphosis, and Japanese patients favor pelvic compensation via retroversion. Patient ethnicity should be considered when evaluating the sagittal plane and surgical correction strategies. Level of Evidence: 3

Clinical outcomes of combined anterior and posterior spinal fusion for dystrophic thoracolumbar spinal deformities of neurofibromatosis-1: fate of nonvascularized anterior fibular strut grafts.

Study Design. Retrospective study. Objective. To analyze the clinical outcomes of anterior and posterior spinal fusion (APSF) using a fibular strut autograft (FSAG) and to investigate the morphological changes in the reconstructed spinal column of dystrophic deformities in neurofibromatosis (NF)-1. Summary of Background Data. APSF is desirable for dystrophic deformities in NF-1 with more than 50° of dystrophic kyphosis. There are few reports regarding the clinical outcomes of APSF in which the morphological changes over time of the anterior strut graft have been investigated. Methods. The clinical and radiographic outcomes of APSF with FSAG were investigated in 10 consecutive patients with dystrophic deformity in NF-1. For qualitative and quantitative analyses, the chronological changes in the FSAG configuration, length, and diameter were evaluated. Results. The mean follow-up period was 9 years, 9 months (range, 1–30 years). Graft bone erosion and postoperative curve progression were not observed in any patient. In quantitative analyses of the anterior strut, the mean ratio of the latest and immediately postoperative FSAG lengths was 0.98 (0.93–1.09). The mean central/peripheral ratios of the FSAG diameter (central portion/[upper end + lower end]/2) were 1.02 (0.92–1.10) immediately after surgery, and 1.01 (0.92–1.07) at the latest follow-up, with no significant change between these 2 time points (P = 0.937). The mean preoperative cross-sectional area of the apical vertebral body and its mean virtual cross-sectional area at the final follow-up were 3.80 (1.83–5.43) and 4.87 (2.46–7.00) cm2, respectively, with a significant difference between these 2 parameters (P = 0.0078). The mean final/preoperative ratio was 1.31 (1.10–1.43). Conclusion. APSF with FSAG for dystrophic deformity in NF-1 successfully reconstructed a reliable spinal column with a rich bone stock. The FSAG and surrounding vertebral bodies were free from postoperative erosion due to dystrophic changes and maintained their stability for a long time.

Pedicle screws with a thin hydroxyapatite coating for improving fixation at the bone-implant interface in the osteoporotic spine: experimental study in a porcine model

OBJECTIVE Instrumentation failure caused by the loosening of pedicle screws (PSs) in patients with osteoporosis is a serious problem after spinal surgery. The addition of a thin hydroxyapatite (HA) surface coating applied by using a sputtering process was reported recently to be a promising method for providing bone conduction around an implant without a significant risk of coating-layer breakage. In this study, the authors evaluated the biomechanical and histological features of the bone-implant interface (BII) of PSs with a thin HA coating in an in vivo porcine osteoporotic spine model. METHODS Three types of PSs (untreated/standard [STPS], sandblasted [BLPS], and HA-coated [HAPS] PSs) were implanted into the thoracic and lumbar spine (T9-L6) of 8 mature Clawn miniature pigs (6 ovariectomized [osteoporosis group] and 2 sham-operated [control group] pigs). The spines were harvested from the osteoporosis group at 0, 2, 4, 8, 12, or 24 weeks after PS placement and from the control group at 0 or 24 weeks. Their bone mineral density (BMD) was measured by peripheral quantitative CT. Histological evaluation of the BIIs was conducted by performing bone volume/tissue volume and bone surface/implant surface measurements. The strength of the BII was evaluated with extraction torque testing. RESULTS The BMD decreased significantly in the osteoporosis group (p < 0.01). HAPSs exhibited the greatest mean extraction peak torque at 8 weeks, and HAPSs and BLPSs exhibited significantly greater mean torque than the STPSs at 12 weeks (p < 0.05). The bone surface/implant surface ratio was significantly higher for HAPSs than for STPSs after 2 weeks (p < 0.05), and bonding between bone and the implant surface was maintained until 24 weeks with no detachment of the coating layer. In contrast, the bone volume/tissue volume ratio was significantly higher for HAPSs than for BLPSs or STPSs only at 4 weeks. CONCLUSIONS Using PSs with a thin HA coating applied using a sputtering process strengthens bonding at the BII, which might improve early implant fixation after spinal surgery for osteoporosis. However, the absence of increased bone mass around the screw remains a concern; prescribing osteoporosis treatment to improve bone quality might be necessary to prevent fractures around the screws.

Ethnic variations in radiographic parameters and SRS-22 scores in adult spinal deformity

Study Design: Retrospective review of North American and Japanese adult spinal deformity (ASD) database. Objective: To investigate the ethnical differences in radiographic parameters and Scoliosis Research Society (SRS)-22 between North American and Japanese ASD. Summary of Background Data: Previous comparison study between North American and Japanese ASD patients has revealed Japanese patients had marked pelvic tilt deformity and had lower Oswestry Disability Index scores corresponding to established thresholds of radiographic deformity. However, the subjects of the previous study included relatively younger ASD patients (above 18 y) of idiopathic origin. Materials and Methods: Total 282 ASD patients older than 50 years, 211 patients from North America (United States) and 71 patients from Japan (JP), with minimum 2-year follow-up postoperatively were included in the study. Radiologic parameters were compared at the baseline and at 2-year follow-up. SRS-22 score was used for the comparison of clinical outcome. Results: At baseline, Japan showed significantly worse sagittal alignment such as smaller lumbar lordosis (LL), larger pelvic incidence (PI), and larger sagittal vertical axis than United States. However, Japan had significantly fewer levels fused than United States (US, 12.66±4.6; JP, 8.49±2.7). At 2 years after the surgery, Japan still had significantly worse residual sagittal deformity. Comparison of SRS-22 scores revealed Japan had better pain but worse functional domain scores at baseline which improved to comparable levels to the United States at 2 years. Self-image and mental health scores in Japan were significantly worse both at baseline and at 2 years. Analysis of factors affecting SRS-22 satisfaction score at 2 years revealed that previous spinal fusion surgery in the United States and LL, PI-LL, and sagittal vertical axis at 2 years in Japan had significant correlation. Conclusions: These similarities and discrepancies may be influenced by the cultural or lifestyle differences between both nations and should be considered when interpreting the results of ASD studies among different ethnicities.

Study protocol for the G-SPIRIT trial: a randomised, placebo-controlled, double-blinded phase III trial of granulocyte colony-stimulating factor-mediated neuroprotection for acute spinal cord injury

Introduction Granulocyte colony-stimulating factor (G-CSF) is generally used for neutropaenia. Previous experimental studies revealed that G-CSF promoted neurological recovery after spinal cord injury (SCI). Next, we moved to early phase of clinical trials. In a phase I/IIa trial, no adverse events were observed. Next, we conducted a non-randomised, non-blinded, comparative trial, which suggested the efficacy of G-CSF for promoting neurological recovery. Based on those results, we are now performing a phase III trial. Methods and analysis The objective of this study is to evaluate the efficacy of G-CSF for acute SCI. The study design is a prospective, multicentre, randomised, double-blinded, placebo-controlled comparative study. The current trial includes cervical SCI (severity of American Spinal Injury Association (ASIA) Impairment Scale B/C) within 48 hours after injury. Patients are randomly assigned to G-CSF and placebo groups. The G-CSF group is administered 400 µg/m2/day×5 days of G-CSF in normal saline via intravenous infusion for 5 consecutive days. The placebo group is similarly administered a placebo. Our primary endpoint is changes in ASIA motor scores from baseline to 3 months. Each group includes 44 patients (88 total patients). Ethics and dissemination The study will be conducted according to the principles of the World Medical Association Declaration of Helsinki and in accordance with the Japanese Medical Research Involving Human Subjects Act and other guidelines, regulations and Acts. Results of the clinical study will be submitted to the head of the respective clinical study site as a report after conclusion of the clinical study by the sponsor-investigator. Even if the results are not favourable despite conducting the clinical study properly, the data will be published as a paper. Trial registration number UMIN000018752.

Dynamic sagittal balance evaluated by 3-dimentional gait analysis in patients with degenerative lumbar kyphosis

Method Twenty-six patients with DLKS underwent gait analysis using 3-dimentional motion analysis system (3D-MAS). Two reflection markers were attached to the skin surface on C7 and S1 spinous processes in all patients. Then they walked on treadmill at self-selected walking speed, and 3-dementional location of these surface makers (C7.S1) were recorded by synchronized 4 cameras that were placed separately. The angles between vertical axis and the line C7-S1 (dynamic-trunk angle: D-TA) and horizontally projected distance of the line C7-S1 (dynamic sagittal vertical axis; D-SVA) were continuously recorded during walking. D-TA and D-SVA were compared to static trunk angle (S-TA) and static SVA(S-SVA) that were obtained regular standing fulllength lateral X-ray.