Relationships between radiographic parameters and spinopelvic muscles in adult spinal deformity patients

Introduction While the clinical impact of coronal and sagittal alignment in adult spinal deformity (ASD) patients (pts) is established, there is a paucity of data in terms of axial plane deformity and potential association between muscle degenera- tion and 3D deformity. The purpose of this study was to analyze spinopelvic muscles characteristics in association with the 3D deformity of ASD patients. Methods This is a prospective cohort study; primary lumbar scoliosis patients (Cobb > 20°) were enrolled and sustained a low-dose X-rays with 3D spinal reconstructions and a fat/water separation MRI (from C7 to the knee). Volumetric 3D reconstructions and fat infiltration (FI) of 6 muscles groups were performed. Relationships between muscular data, radio- graphic parameters and health-related quality of life were investigated. Patients were stratified and compared based on the SRS classification, the odontoid-hip axis (ODHA) angle (> or 0.05). Pts with ODHA > 6.1° or pelvic incidence minus lumbar lordosis > 10° had significantly higher FI for the 6 muscular groups, patients with pelvic tilt > 20° had significantly higher FI for erector spinae, hip flexors and extensors (p < 0.05). SF36-PCS significantly correlated with the muscular volume; SRS and Oswestry disability index correlated with the erectors spinae volume (p < 0.05). Conclusion This study analyzed for the first time the relationship between 3D radiographic parameters and muscular charac- teristics in ASD. Sagittal malalignment is associated with increased FI and decreased muscle volumes with poor outcomes

Volume of spinopelvic muscles: comparison between adult spinal deformity patients and asymptomatic subjects

Purpose: Spinal muscles are a major component of posture in spinal pathologies and changes to the spine with aging. Specifically, spinopelvic muscles may compensate for underlying anomalies such as pelvic retroversion, knee flexion, and cervical or thoracic spinal balance abnormalities. To increase understanding between muscular characteristics and compensatory mechanisms, this study aimed to compare the volume of spinopelvic muscles in adults with a spinal deformity (ASD) to a control group of well-aligned adult subjects. Methods: Twenty-eight lumbar ASD patients [Cobb angle > 20°, > 40 years old (yo)] were prospectively included and compared to 35 normal subjects divided into 2 different groups: one group of young (Y) subjects (n = 23,  40 yo). All subjects had a fat/water separation MRI (from C7 to the knees). Volumetric 3D reconstructions of 30 spinopelvic muscles were performed and muscles volumes were compared. Results: Mean age was 60 ± 16 yo, without significant differences between the ASD and O groups (57 ± 11 yo). Age and BMI were smaller in the young group. Mean Cobb angle of the ASD group was 45 ± 11°. Comparing the ASD and O groups, total muscular volume was similar; however, erector spinae (0.24 ± 0.06 vs 0.68 ± 0.08 dm3, p = 0.001), iliopsoas (0.49 ± 0.09 vs 0.60 ± 0.09 dm3, p = 0.001) and obliquus (0.42 ± 0.08 vs 0.50 ± 0.08 dm3, p = 0.02) were significantly smaller in the ASD group. Comparing the Y and the ASD groups, total muscular volume was higher in the Y group than the ASD group (+ 3.3 dm3, p = 0.003) and erector spinae (0.24 ± 0.06 vs 0.74 ± 0.08, p = 0.0001), gluteus medius (0.51 ± 0.07 vs 0.62 ± 0.13, p = 0.01) and vastus lateralis (1.33 ± 0.21 vs 2.08 ± 0.29, p = 0.001) were significantly bigger in the Y group. Conclusion: This is the first study to compare volume of spinopelvic muscles between ASD patients and a control group without spinal deformity. Our results demonstrate that muscular degeneration has a double origin: aging and deformity. Erector spinae, iliopsoas, and obliquus are the muscles most affected by degeneration

Global alignment taking into account the cervical spine with odontoid hip axis angle (OD-HA)

Introduction: Global alignment analysis is of upmost importance in adult spinal deformity patients (ASD). Numerous parameters exist in the literature to measure global alignment based upon C7 or T1. One common limitation of these parameters is that they neglect the cervical segment which is essential in spinal compensatory mechanisms and in horizontal gaze preservation. A recent stereoradiography analysis of asymptomatic subjects introduced a new 3D parameter (ODHA), defined as the angle between the vertical reference line and the line joining the odontoid tip (OD) to hip axis center (HA). Thus, the goal of this study was to analyze 3D global alignment of ASD patients using the new parameter odontoid hip axis angle and its relationship to other spinal parameters. Methods: In this prospective study, 90 adult patients with lumbar scoliosis (Cobb > 20°) were included. All subjects underwent low dose biplanar X-rays with 3D spinal reconstructions. Based on published normative values of ODHA, we defined abnormally high value as mean ODHA of asymptomatic subject + 2SD (i.e., ODHA > 6.1°). Values of 3D radiographic parameters and ODI were compared between patients with ODHA > 6.1° and < 6.1°. Results: Mean ODHA was 5+/− 3.6° (0.4° to 18.6°). 22 patients had abnormally high ODHA. They were older than the 68 other patients (68+/− 9y vs 53+/− 14y, p = 0.001), without any significant difference in terms of sex, BMI and rate of rotatory subluxation (54% vs 62%, p = 0.06). However, coronal and sagittal deformity was more important in patients with abnormal ODHA (larger Cobb angle, coronal malalignment, pelvic tilt and lower lumbar lordosis). Patients with abnormal ODHA had significantly worst ODI (50+/− 23 vs 30+/− 18, p = 0.0005). Conclusion: Extreme values of ODHA are observed in significantly older patients with significant functional impairment. In addition, in these patients with sagittal malalignment with loss of lumbar lordosis, who recruit compensatory mechanisms such as pelvic retroversion, the cervical area is also involved with a posture in cervical hyperlordosis to maintain the head over the pelvis. Thus, ODHA is an interesting parameter allowing a more comprehensive alignment measurement taking into account the mechanisms of compensation of the cervical spine to the pelvis

Pre-surgical CT-assessment of neurogenic myositis ossificans of the hip and risk factors of recurrence: a series of 101 consecutive patients

International audienceBackground: Neurogenic Myositis Ossificans (NMO) is a rare disabling pathology characterized by peri-articular heterotopic ossifications following severe peripheral or central nervous system injuries. It results in ankylosis and vessels or nerves compressions. Our study aimed to describe the pre-operative findings of patients with NMO of the hip using biphasic computerized tomography (CT). Methods: Between 2006 and 2012, we retrospectively analyzed 101 consecutive patients with hip NMO. We analyzed all CTs and surgical reports following a standardized grid depicting the osteoma and its relations with joint capsule, vessels and nerves and bone mineralization. We studied surgical complications and recurrence during follow-up. Chi2-test and Fischer's test were performed to compare qualitative values with respectively normal and non-normal distribution. Quantitative values were analyzed with a one factor analysis of variance (ANOVA) test. Agreement between pre-surgical CT and surgical observations was evaluated with Cohen's kappa test. Results: Correlation between pre-operative CT and surgical findings was excellent regarding relationships with vessels (0,82) and was good concerning relationships with sciatic nerves (0.62) and with joint capsule (0.68). Close contact or disruption of joint capsule (p = 0.005), joint space narrowing (p = 0.007) and bone demineralization (p < 0.001) were correlated with NMO recurrence.Conclusions : Biphasic enhanced-CT allows pre-operative assessment of NMO with good correlation to surgical observations and helps prevent surgical complications