The controlled study of diffuse idiopathic skeletal hyperostosis for the assessment of physical function in elderly populations.

BACKGROUND: Diffuse idiopathic skeletal hyperostosis (DISH) is associated with increasing age, obesity, and diabetes mellitus. However, little is known about the clinical impacts of DISH on physical function and spinal deformity in elderly populations. The purpose of this study was to elucidate the influence of DISH on physical function, spinal deformity, and health-related quality of life (HRQOL) in elderly populations. METHODS: We enrolled 504 volunteers (203 men and 301 women, mean age 74.0 years). Height, weight, body mass index (BMI), blood pressure, grip strength, one-leg standing time, sit-and-reach, functional reach, and bone mineral density (BMD) were measured. Using whole spine standing X-rays, the prevalence, location, and numbers of fused vertebra of DISH and spinopelvic parameters were measured. HRQOL measures, including the Oswestry Disability Index and the EuroQuol-5D were also obtained. We compared DISH subjects with control subjects of age and sex matching. We compared DISH subjects in the thoracic spine (T-DISH) to those in the thoraco-lumbar spine (TL-DISH). RESULTS: DISH occurred more frequently in men (14.3%) than in women (4.3%). The mean age was significantly higher of subjects with DISH than of those without DISH. The mean number of fused vertebra by DISH was 5.5 ± 1.5, and T-DISH was observed in 57% cases. DISH group showed greater body weights, BMIs, blood pressures, and BMD in the lumbar spine compared to the control group. No inter-group differences were observed in physical function, HRQOL and spinopelvic parameters. Subjects with TL-DISH had significantly lower values of sit-and-reach and functional reach than those with T-DISH. CONCLUSIONS: Subjects with DISH showed greater body weights, BMIs, blood pressures, and BMD compared to age- and sex-matched controls, while physical function, spinal alignment, and HRQOL were comparable between groups.

Cortical Thickness Index of the Proximal Femur: A Radiographic Parameter for Preliminary Assessment of Bone Mineral Density and Osteoporosis Status in the Age 50 Years and Over Population.

BACKGROUND: Bone mineral density (BMD) is the indicator of bone quality in at-risk individuals. Along with the fracture risk assessment tool (FRAX), a quick assessment of BMD from routine radiographs may be useful in the case of lacking X-ray absorptiometry data. This study aimed to investigate the correlation of cortical thickness index (CTI) and canal flare index (CFI) with BMD and FRAX and to evaluate their ability to predict femoral neck BMD (nBMD) and FRAX in the general elderly population. METHODS: A total of 560 volunteers (age ≥ 50 years) who underwent hip-spine X-ray, BMD scanning and FRAX calculation were retrospectively reviewed. CTI and CFI were measured on anteroposterior radiographs and analyzed for their correlation with BMD and FRAX and for their ability to predict nBMD. The ability of CTI to predict osteoporosis status (OPS) and fracture risk status (FRS) was also investigated and the threshold values were calculated. All the analyses were performed separately on male and female subjects. RESULTS: Significant differences in CTI, CFI, nBMD and FRAX between males and females were observed. CTI and CFI demonstrated significant positive correlation with nBMD and FRAX (all p < 0.001) in both males and females. CTI, height, and weight significantly predicted nBMD. CTI statistically predicted OPS and FRS, and the values of 0.56 and 0.62 were computed as CTI thresholds for males and females, respectively. CONCLUSIONS: CTI was significantly correlated with nBMD and it predicted nBMD at good prediction levels. Therefore, CTI may be used as a supportive tool in the assessment of OPS and FRS besides BMD and FRAX in clinical practice.

Assessment of the Change in Alignment of Fixed Segment After Adult Spinal Deformity Surgery.

STUDY DESIGN: Retrospective study. OBJECTIVE: To determine the prevalence of loss in fixed segment alignment after surgical correction of adult spinal deformity (ASD) and identify associated risk factors. SUMMARY OF BACKGROUND DATA: Altered fixed segment alignment influences global spinal alignment; however, associated risk factors have not been determined. METHODS: Data of 63 patients with ASD (55 females; mean age, 68.0 yrs), who underwent corrective fusion from the lower thoracic spine to the pelvis and completed the 2-year follow up, were retrospectively analyzed. Change in alignment early postoperatively and at 2 years postoperatively was evaluated using the fixed segmental angle (FSA) and fixed vertebral angle (FVA). The predictive value of the following parameters was evaluated: age, sex, body mass index (BMI), high grade osteotomy, rod material, screw loosening, spinopelvic parameters [T1 pelvic angle (TPA), sagittal vertical axis (SVA), pelvic tilt (PT), lumbar lordosis (LL), thoracic kyphosis (TK), and proximal junctional kyphosis (PJA), and Oswestry Disability Index (ODI) scores]. RESULTS: Change of 2.4° in FSA and -3.1° in FVA were identified 2 years postoperatively, with higher intrarater and interrater reliability for FSA. Based on minimal detectable change in FSA, patients were classified into two groups: (+) loss (ΔFSA >3°) and (-) loss (ΔFSA ≤3°). Correction loss occurred in 17 patients; these patients had a greater BMI, higher rate of high-grade osteotomies, commercially pure titanium (CP) rods implanted, screw loosening, higher preoperative and postoperative TPA, and higher TPA, SVA, and PT after 2 years, than patients without correction loss. CONCLUSION: The loss of sagittal fixed segment alignment was relatively high at 27%. Greater BMI, high-grade osteotomies, CP rod use, and sagittal malalignment were associated with correction loss after ASD surgery. LEVEL OF EVIDENCE: 4.

Assessment of the Cross-Sectional Areas of the Psoas Major and Multifidus Muscles in Patients With Adult Spinal Deformity: A Case-Control Study.

STUDY DESIGN: This is a case-control study. OBJECTIVE: The present study aimed to compare the cross-sectional areas of the psoas major and multifidus muscles between elderly patients with adult spinal deformity (ASD) and age-matched and body weight-matched controls, and to evaluate the associations between the cross-sectional areas of these muscles and the severity of spinal deformity. SUMMARY OF BACKGROUND DATA: The study included 49 female kyphosis patients with mild scoliosis (Cobb angle <20 degrees; mean age, 70.9 y, group D). The control group (group C) included age-matched and body weight-matched female patients who underwent abdominal surgery (n=98; mean age, 71.7 y). MATERIALS AND METHODS: The cross-sectional areas of the bilateral psoas majors and multifidus muscles were calculated using preoperative L4/L5 axial computed tomography images. In group D, the following spinopelvic parameters were assessed: sagittal vertical axis, pelvic tilt, pelvic incidence, lumbar lordosis, and thoracic kyphosis. The relationships between the muscle cross-sectional areas and spinopelvic parameters were evaluated. RESULTS: The cross-sectional area of the multifidus muscle was lower in group D than in group C. However, the cross-sectional area of the psoas major muscle was not different between the 2 groups. In multiple regression analysis, the cross-sectional area of the multifidus muscle was significantly associated with all spinopelvic parameters. CONCLUSIONS: The cross-sectional area of the multifidus muscle might be lower in elderly patients with ASD than in controls. In the elderly population, the severity of sagittal spinal deformity might be correlated with the cross-sectional area of the multifidus muscle. Therefore, muscle imbalances between the flexors and extensors of the spine could participate in the pathology of ASD.

The cohort study for the determination of reference values for spinopelvic parameters (T1 pelvic angle and global tilt) in elderly volunteers.

PURPOSE: T1 pelvic angle (TPA) and global tilt (GT) are spinopelvic parameters that account for trunk anteversion and pelvic retroversion. To investigate spinopelvic parameters, especially TPA and GT, in Japanese adults and determine norms for each parameter related to health-related quality of life (HRQOL). MATERIALS AND METHODS: Six hundred and fifty-six volunteers (262 men and 394 women) aged 50-92 years (mean, 72.8 years) were enrolled in this study. The incidence of vertebral fracture, spondylolisthesis and coronal malalignment were measured. Five spinopelvic parameters (TPA, GT, sagittal vertical axis [SVA], pelvic tilt [PT], and pelvic incidence-lumbar lordosis [PI-LL]) were measured using whole spine standing radiographs. The mean values for each parameter were estimated by sex and decade of life. HRQOL measures, including the Oswestry Disability Index (ODI) and EuroQuol-5D (EQ-5D), were also obtained. Pearson's correlation coefficients were determined between each parameter and HRQOL measure. Moreover, the factors contributing to the QOL score were calculated using logistic regression with age, sex, the existence of vertebral fracture and spondylolisthesis, coronal malalignment (coronal curve >30°) and sagittal malalignment (SVA >95 mm) as explanatory variables and the presence of disability (ODI >40) as a free variable. RESULTS: The mean values for the spinopelvic parameters were as follows: TPA, 17.9°; GT, 23.2°; SVA, 50.2 mm; PT, 18.6°; and PI-LL, 7.5°. TPA and GT strongly correlated with each other (r = 0.990) and with the other spinopelvic parameters. TPA and GT correlated with ODI (r = 0.339, r = 0.348, respectively) and EQ-5D (r = -0.285, r = -0.288, respectively), similar to those for SVA. TPA, GT, PT, and PI-LL were significantly higher in women than in men. PT and PI-LL gradually increased with age, while TPA, GT, and SVA tended to deteriorate after the 7th decade. Based on a logistic regression analysis, the deterioration of ODI was mostly affected by the sagittal malalignment. The TPA and GT cut-off values for severe disability (ODI >40) based on linear regression modeling were 26.0° and 33.7°, respectively. CONCLUSIONS: We determined reference values for spinopelvic parameters in elderly volunteers. Similar to SVA, TPA and GT correlated with HRQOL. TPA, GT, PT, and PI-LL were worse in women and progressed with age.

In Vivo Assessment of Bone Graft/Endplate Contact Pressure in a Caprine Interbody Pseudarthrosis Model: A Preliminary Biomechanical Characterization of the Fusion Process for the Development of a Microelectromechanical Systems (MEMS) Biosensor.

BACKGROUND: In this preliminary study we used a goat model to quantify pressure at an interbody bone graft interface. Although the study was designed to assess fusion status, the concept behind the technology could lead to early detection of implant failure and potential hazardous complications related to motion-preservation devices. The purpose of this study was to investigate the feasibility of in vivo pressure monitoring as a strategy to determine fusion status. METHODS: Telemetric pressure transducers were implanted, and pressure at the bone graft interfaces of cervical interbody fusion autografts placed into living goats (Groups A and B) was evaluated. Group A constituted the 4-month survival group and Group B the 6-month survival group. One goat served as the study control (Group C) and was not implanted with a pressure transducer. An additional six cadaveric goat cervical spines (Group D) were obtained from a local slaughterhouse and implanted with bone grafts and ventral plates and used for in vitro biomechanical comparison to the specimens from Groups A and B. RESULTS: All goats demonstrated an increase in interface pressure within the first 10 days postoperatively, with the largest relative change in pressure occurring between the sixth and ninth days. The goats from Groups A and B had a 200% to 400% increase in relative pressure. CONCLUSIONS: Although this was a pilot study to assess pressure as an indicator for a fusion or pseudarthrosis, the preliminary data suggest that early bone healing is detectable by an increase in pressure. Thus, pressure may serve as an indicator of fusion status by detecting altered biomechanical parameters.

A prospective randomized study of posterolateral lumbar fusion using osteogenic protein-1 (OP-1) versus local autograft with ceramic bone substitute: emphasis of surgical exploration and histologic assessment.

STUDY DESIGN: A prospective, randomized and controlled study. OBJECTIVES: To evaluate the osteoinductive property of Osteogenic Protein-1 (OP-1 or BMP-7) and fusion rate in human instrumented posterolateral lumbar fusion through radiographic examination, surgical exploration, and histologic assessment. SUMMARY OF BACKGROUND DATA: The use of osteoinductive agents is a current topic in spinal fusion. Numerous preclinical investigations have demonstrated efficacy of osteoinductive proteins in spinal fusion, but few human clinical studies have been reported. METHODS: Nineteen patients with L3-L4 or L4-L5 degenerative spondylolisthesis underwent posterolateral lumbar fusion using pedicle screw instrumentation. The patients were randomized to receive either OP-1 Putty (3.5 mg OP-1/g of collagen matrix per side) alone (n = 9), or local autograft with HA-TCP granules (n = 10). Fusion status was evaluated using plain radiography and CT scan. Radiographic fusion criteria included less than 5 degrees of angular motion, less than 2 mm of translation, and evidence of bridging bone in the posterolateral lumbar area in which the graft materials were placed following decortication. After a minimum 1-year follow-up, the patients who showed radiographic evidence of fusion underwent instrumentation removal and surgical exploration of the fusion site. Biopsy specimens were taken from the fusion mass and evaluated histologically. RESULTS: Radiographic fusion rate was 7 of 9 OP-1 patients and 9 of 10 control patients. Based on surgical exploration of these 16 patients, new bone formation was macroscopically observed in the posterolateral lumbar region in all cases; however, solid fusion was observed in 4 of 7OP-1 and 7 of 9 HA-TCP/autograft patients. Histologic assessment demonstrated viable bone in 6 of 7 OP-1 patients. All the control (HA-TCP/autograft) specimens contained viable bone and fibrous tissue surrounding ceramic granules, suggesting slow incorporation of the graft material. CONCLUSIONS: In a human posterolateral lumbar spine trial, OP-1 reliably induced viable amounts of new bone formation, but the fusion success rate evaluated by surgical exploration was only 4 of 7.