Full Spine Research Articles

A multicenter cohort study on the association between prehospital immobilization and functional outcome of patients following spinal injury in Asia

Prehospital spinal immobilization is a widely used procedure in the emergency medical service (EMS) system worldwide, while the incidence of patients with spinal injury (SI) is relatively low, and unnecessary prehospital spinal immobilization is associated with patient complications. This study aimed to determine the association between prehospital spine immobilization and favorable functional outcomes at hospital discharge among trauma patients with SI. We conducted a retrospective cohort study using the Pan-Asia Trauma Outcomes Study (PATOS) registry data from January 1, 2016, to November 30, 2018. A total of 759 patients with SI were enrolled from 43,752 trauma patients in the PATOS registry during the study period. The subjects had a median age of 58 years (Q1–Q3, 41–72), and 438 (57.7%) patients had prehospital spine immobilization. Overall, prehospital spinal immobilization was not associated with favorable functional outcomes at discharge in multivariable logistic regression (aOR 1.06; 95% CI 0.62–1.81, p = 0.826). However, in the subgroup of cervical SI, prehospital spinal immobilization was associated with favorable functional outcomes at discharge (aOR 3.14; 95% CI 1.04–9.50; p = 0.043). Therefore, we suggest that paramedics should be more careful when determining the presence of a cervical SI and should apply full spine immobilization if possible.

Do Age-Related Variations Of Sagittal Alignment Rely On SpinoPelvic Organization? An Observational Study Of 1540 Subjects.

Descriptive radiographic analysis of a prospective multi-center database. This study aims to provide normative values of spinopelvic parameters and their correlations according to age and pelvic incidence (PI) of subjects without spinal deformity. After Institutional Review Board (IRB) approval, 1540 full spine radiographs were analyzed. Subjects were divided into 3 groups of PI: low PI < 45°, intermediate PI 45-60°, high PI > 60°, and then stratified by age (20-34, 35-49, 50-64, > 65 Y.O). Pelvic and spinal parameters were measured. Statistical analysis between parameters was performed using Bayesian inference and correlation. Mean age was 53.5years (845 females, 695 males, range 20-93years).In low PI group, lumbar lordosis (LL) decrease was mainly observed in the 2 younger age groups.In medium and high PI groups, loss of lordosis was linear during aging and occurred mainly on the distal arch of lordosis. Moderate PI group had a stable lordosis apex and thoracolumbar inflection point. High PI group had a stable thoracolumbar inflection point and a more distal lordosis apex in elderly subjects.For all subjects, kyphosis and pelvic tilt (PT) increased with age.There was a constant chain of correlation between PI and age groups. Proximal lumbar lordosis (PLL) was correlated with kyphosis and sagittal vertical axis (SVA C7), while the distal lumbar lordosis (DLL) was correlated with PI and PT. This study provides a detailed repository of sagittal spinopelvic parameters normative values with detailed analysis of segmental kyphosis and lordosis distribution according to gender, age, and PI.

Slanted slot was the most resistant to failure of ventral slot techniques tested in rabbit cervical vertebrae

The ventral slot technique is used to relieve neural compression secondary to intervertebral disc degeneration or disease. In the present study, the biomechanical properties of three different ventral surgical procedures in the rabbit C6–C7 vertebral motion unit (VMU) were assessed and compared with the intact C6–C7 VMU. The ventral slot procedure (slanted, full, or mini; n = 8/group) was performed on these cervical vertebrae. Normal spine torsion and flexion values were compared to those of spines subjected to slanted, full, and mini slot surgery. The slanted slot spines were the most stable, maintaining 70% of normal cervical spine strength, compared to 26% with the full slot and 30% with the mini slot. Regarding torsion, slanted slot spines showed 74% stability compared to the normal cervical spine, while the full slot and mini slot spines showed 58% and 62% stability, respectively. Flexion values were lower after all versions of the ventral slot procedure than in the normal spine, with the greatest flexion difference occurring after the full slot procedure (21% of the normal flexion value). The flexion values also differed significantly between the slanted and full spine groups, and all operated spines showing roughly 60% torsion rates compared with normal spines. The slanted slot maintains more stability in rabbit cervical spine than the other procedures. To our knowledge, this was the first study to examine biomechanical failure differences between the distinct versions of this ventral slot procedure.

Institution-wide shape analysis of 3D spinal curvature and global alignment parameters.

The spine is an articulated, 3D structure with 6 degrees of translational and rotational freedom. Clinical studies have shown spinal deformities are associated with pain and functional disability in both adult and pediatric populations. Clinical decision making relies on accurate characterization of the spinal deformity and monitoring of its progression over time. However, Cobb angle measurements are time-consuming, are limited by interobserver variability, and represent a simplified 2D view of a 3D structure. Instead, spine deformities can be described by 3D shape parameters, addressing the limitations of current measurement methods. To this end, we develop and validate a deep learning algorithm to automatically extract the vertebral midline (from the upper endplate of S1 to the lower endplate of C7) for frontal and lateral radiographs. Our results demonstrate robust performance across datasets and patient populations. Approximations of 3D spines are reconstructed from the unit normalized midline curves of 20,118 pairs of full spine radiographs belonging to 15,378 patients acquired at our institution between 2008 and 2020. The resulting 3D dataset is used to describe global imbalance parameters in the patient population and to build a statistical shape model to describe global spine shape variations in preoperative deformity patients via eight interpretable shape parameters. The developed method can identify patient subgroups with similar shape characteristics without relying on an existing shape classification system.

Eyelid ptosis and muscle weakness in a child with Kawasaki disease: a case report

BackgroundKawasaki disease (KD) is an acute febrile vasculitis that often occurs in children under 5 years. Ptosis and muscle weakness associated with KD are rarely documented.Case presentationWe present a case of KD with eyelid ptosis and muscle weakness in a 3-year-old boy. At admission, grade IV and grade III muscle strength were recorded for upper and lower limbs, respectively. Diminished patellar tendon reflex was noted. Laboratory evaluation showed hypokalemia with the serum potassium concentration of 2.62 mmol/L. Intravenous immunoglobulin (IVIG) and aspirin were initiated immediately accompanied with methylprednisolone for adjunctive therapy. Potassium supplement was administered at the same time, which resulted in the correction of hypokalemia on the 2nd day of admission but no improvement in ptosis and muscle weakness. Neostigmine testing, lumber puncture, electromyography, and cerebral and full spine MRI were performed, which, however, did not find evidence for neural and muscle diseases. On the 5th day, the fever was resolved. On the 6th day, eyelid ptosis disappeared. And on the 14th day, the muscle strength and muscle tension returned to normal, patellar tendon reflex could be drawn out normally, and the boy regained full ambulatory ability.ConclusionsKD might affect the neural and muscular systems, and KD complicated with eyelid ptosis and muscle weakness is responsive to the standard anti-inflammatory treatment plus adjunctive corticosteroid therapy.

Post-marketing surveillance on safety and efficacy of posterior spinal correction and fusion with the CD Horizon Solera instrumentation for adolescent idiopathic scoliosis. A retrospective cohort study

BackgroundPost-Market Clinical Follow-Up has been integrated into the new Medical Device Regulations since 2020. The CD Horizon Solera 4.75 mm instrumentation (CD-Solera) was introduced worldwide in 2009, and specifically intended for surgical treatment of pediatric and adolescent scoliosis patients. The objective of this study was to evaluate the safety and efficacy of the CD-solera 4.75 instrumentation in surgical treatment of adolescent idiopathic scoliosis (AIS). Methods94 consecutive AIS patients, 82 female, 12 male, who underwent posterior correction with CD-Solera instrumentation between 2010 and 2016 at age 14.8 ± 1.6 years, were retrospectively included. The minimum follow-up was two years. On pre- and postoperative biplanar full spine radiographs Cobb angles of the primary and secondary curves and sagittal profile were measured before surgery, immediately postoperative, and at two-year follow-up. Medical records were reviewed for complications. Clinical outcome was analyzed using theSRS-22r questionnaire. ResultsIn this study 77% of the patients had a structural thoracic curve (type Lenke 1 or 2), and 23% had a structural (thoraco-)lumbar curve (Lenke 3-6). A correction of 55.1% and 51.7% was achieved respectively immediately post-operative, and at last-year follow up for the primary curve. The mean loss of correction was 2°. Health related quality of life was 4.0 (good) on the SRS-22r-questionnaire. In total six revision operations were executed, of which one was related to the material (rod breakage). Other reasons for revision operation were not due to the material. No neurological problems were encountered. ConclusionIn patients with AIS the initial correction and maintenance of correction as achieved by posterior spinal fusion using the CD-Solera instrumentation, is comparable to other reported devices. Complication rates are low and health related quality of life comparable to literature. The CD-Solera can be regarded as a safe and effective instrumentation in surgical treatment of AIS.

"Floating Cervical Spine Injuries": Craniocervical Dissociation with Associated, Noncontiguous, Unstable Cervical or Cervicothoracic Spine Fracture.

Advances in prehospital life support of patients who have sustained high-energy trauma have resulted in an increase in the number of patients with craniocervical dissociations (CCDs) surviving. With better imaging and more severely injured patients surviving, we are now seeing other associated injuries. CCDs in association with unstable, noncontiguous, subaxial spine injuries have not been described. The objective of this study was to (1) describe this injury pattern and its characteristics, including the mechanism of injury, injury levels, and neurological deficits, and (2) understand prognosis and outcome. After institutional review board approval, a retrospective study of patients who sustained CCD in association with an unstable, circumferential, subaxial, or cervicothroacic spine injury (C3-T2) between January 1, 2003, and August 31, 2018, was done. Review of imaging was performed to identify spine injury localization and type. Demographic data, mechanism of injury, neurological status, type of treatment, and patient outcomes were obtained from the electronic medical records. One hundred seventeen patients with CCD were identified, of which 105 had full spine radiographs. Thirteen (8 male and 5 female) had an associated, noncontiguous, unstable cervical, or cervicothoracic injury. Mean age was 45.4 ± 19 years. No exam could be obtained in 6; in the other 7, 1 was American Spinal Injury Association (ASIA) E, 1 ASIA D, and 5 ASIA A. Operative management of both injuries was planned for all 13 patients; however, 2 died before surgery. At discharge, there were 9 survivors with mean follow up of 2 years; 4 patients were independent (3 ASIA D, 1 ASIA E), and 5 were dependent (1 ASIA C, 4 ASIA A). Approximately 12% of patients with CCD have a floating cervical spine injury. Floating cervical spine injuries have an unfavorable prognosis with 69% surviving to hospital discharge but only 31% functioning independently (ASIA D or E). 4. Floating cervical spine injuries need to be recognized to optimize prognosis, yet even in the best of circumstances, prognosis is guarded.

Clinical study of selection of the upper instrumented vertebra at one level caudal to upper end vertebra in patients with Lenke 5C adolescent idiopathic scoliosis

Objective: To investigate whether the upper instrumented vertebra (UIV) can be selected at one level caudal to upper end vertebra (UEV) in Lenke type 5C adolescent idiopathic scoliosis (AIS) patients. Methods: Total of 28 Lenke 5C AIS patients who underwent selective posterior fusion in Drum Tower Hospital of Nanjing University Medical School from September 2013 to September 2015 were included. There were 4 males and 24 females, with an age of (15.0±2.0) years, the Risser sign was graded 2-5. The following imaging parameters were measured on standing full spine X-ray before, immediately after the surgery and at the last follow-up: thoracolumbar/lumbar (TL/L) Cobb angle, coronal balance, UIV translation, lower instrumented vertebra (LIV) translation, UIV tilt, LIV tilt, and thoracic apical vertebral translation (T-AVT), lumbar apical vertebral translation (L-AVT). The patients were divided into two groups: decompensation group (n=6) and non-decompensation group (n=22). Radiographic parameters and Scoliosis Research Society (SRS)-22 scores were compared between the two groups. Results: Six cases (21.4%) had proximal decompensation at the last follow-up. There were no significant differences in Risser grade(3.8±1.0 vs 3.6±1.6), baseline thoracic Cobb angle(25.8°±2.2° vs 26.3°±6.4°) and TL/L Cobb angle(43.7°±3.4° vs 45.2°±6.5°) between the two groups (all P>0.05). However, the baseline lumbar/thoracic apical vertebra translation (L-T AVT ratio) was significantly higher in patients with proximal decompensation (6.3±1.3 vs 4.0±2.0, P=0.048). Conclusion: Selecting UIV at one level caudal to UEV, would not increase the incidence of proximal decompensation in Lenke 5C AIS patients with Risser higher than grade 2, the smaller baseline L-T AVT ratio, and with thoracic compensatory curve over 15°, and can obtain satisfactory clinical results.

Demographics and Clinical Profiles of Patients Visiting a Chiropractic Teaching Clinic in Malaysia

ObjectiveThe objective of this study was to describe the demographics and clinical profiles of patients visiting a chiropractic teaching clinic in Malaysia. MethodsA retrospective descriptive study was conducted using existing medical records of all new patients who visited the International Medical University Bukit Jalil teaching clinic between August 2018 and July 2019. Sociodemographic and lifestyle factors, information on location of presenting complaints, duration of complaint and referral sources were reviewed. Descriptive analyses including mean, mode, standard deviations (SDs), and frequencies were performed. ResultsOf the 1451 patients included in this study, the mean age was (SD) 34.3 (16.1) with 51.1% female. Most of the patients were Chinese (76.0%), followed by Malay (11.6%), Indian (7.72%), and others such as Punjabi and Sabah and Sarawak native (5.0%). Comparing referral sources, the main referrals were self-referred (26.6%) followed by friends and family referrals (25.0%) and other forms of social media and advertising (10.0%). The most frequent location of complaint was the lumbar and pelvic regions, 562 (38.73%) followed by head and neck 400 (27.57%), lower limb 173 (11.92%), upper limb 154 (10.61%), thoracic 133 (9.17%), and full spine 29 (2%). ConclusionThis study provides important information that allows better understanding of patients presenting to a chiropractic teaching clinic in Malaysia. Such findings may contribute to the benchmark data for future strategic planning to ensure sufficient exposure on case mix among chiropractic interns in Malaysia.

140. C2 pelvic angle (C2PA) is a useful intraoperative radiographic parameter that correlates with the risk of developing proximal junctional kyphosis postoperatively

<h3>BACKGROUND CONTEXT</h3> We established the first intraoperative parameter that directly correlates with postoperative proximal junctional kyphosis (PJK). C2 pelvic angle (C2PA) is a novel, intraoperative radiographic parameter used to assess for potential development of PJK. Intraoperative C2PA >15° is a critical angle with 2.5 times the relative risk for developing PJK. No patient with intraoperative C2PA <15° developed PJK. <h3>PURPOSE</h3> PJK is a postoperative complication of adult spinal deformity surgery that leads to poorer patient clinical outcomes. There is no literature on intraoperative assessment of sagittal alignment to prevent PJK. Intraoperative C2PA is a novel, radiographic parameter derived from the difference between global spinal alignment and the alignment proximal to the uninstrumented spine. The goal of this study is to demonstrate a positive relationship between the intraoperative C2PA and PJK. <h3>STUDY DESIGN/SETTING</h3> Prospectively collected cohorts. <h3>PATIENT SAMPLE</h3> Sixty deformity patients from 2015- 2018 who had preop, intraop, immediate postop and 2-year postop full length spine films. <h3>OUTCOME MEASURES</h3> Logistic regression and Chi-square analyses evaluated the relationship between the postop PJA and intraop C2PA/PJA. <h3>Methods</h3> We performed radiographic analysis on 60 deformity patients from 2015- 2018. Of the 60 patients, 35 were fused to the sacrum/pelvis. C2PA is defined as the angle between the posterior superior sacrum, C2 centroid and upper instrumented vertebrae (UIV) centroid and measured in the pre-, intra-, and postop setting (immediate and 2 years or prior to return to OR). PJK was defined as postop PJA >15°. Logistic regression and Chi-square analyses evaluated the relationship between the postop PJA and intraop C2PA/PJA. <h3>Results</h3> Of the 60 patients, 20 had PJK at the 2-year postop X-ray or prior to return to OR films. The intraop C2PA for the non-PJK and PJK group were 12.5° and 21.2°, respectively (p < 0.0001). The intraop PJA for the non-PJK and PJK group were 5.6° and 7.4°, respectively (p=0.04). The relative risk ratio of developing PJK for patients with intraop C2PA >15° was 2.43, and no one with intraop C2PA <15° developed PJK in the 2-year follow-up. <h3>Conclusions</h3> This is the first intraoperative measurement that demonstrates a direct correlation with PJK. Intraoperative C2PA >15° is a critical angle with 2.5 times the relative risk for developing PJK. No patient with intraoperative C2PA <15° developed PJK. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

P6. Spinopelvic alignment changes between seated and standing positions in pre and post total hip replacement patients

<h3>BACKGROUND CONTEXT</h3> The inter-relationship between the hip and spine has been increasingly studied in recent years, particularly as it pertains to the effect of spinal deformity and hip osteoarthritis (OA). Changing from standing (ST) to seated (SE) requires rotation of the femur from an almost vertical plane to the horizontal. OA of the hip significantly limits hip extension, resulting in less ability to recruit pelvic tilt (PT) in ST, and requiring increased PT in SE to compensate for loss of hip flexion. To date, the effect of total hip arthroplasty (THA) in altering spinopelvic SE and ST mechanics has not been reported. <h3>PURPOSE</h3> To investigate the change in spinopelvic alignment parameters between seated and standing positions in pre and post THA patients. <h3>STUDY DESIGN/SETTING</h3> Retrospective review at a single academic institution. <h3>PATIENT SAMPLE</h3> Adult patients undergoing THA with full body sitting and standing radiographs pre- and post-THA. <h3>OUTCOME MEASURES</h3> Spinopelvic alignment measures including pelvic incidence (PI), pelvic tilt (PT), T1 pelvic angle (TPA), sacral slope (SS), sagittal vertical axis (SVA), pelvic incidence and lumbar lordosis mismatch (PI-LL), and lumbar lordosis (LL). <h3>METHODS</h3> Patients ≥18yo undergoing THA for hip OA with full spine SE and ST radiographs pre and post THA were included. Spinopelvic alignment was analyzed pre-THA and post-THA in both ST and SE positions in a relaxed posture with the fingers on the clavicles. Paired t-test analysis was performed to compare Pre-and Post-THA groups. The effect of TL deformity (SVA>50, TPA>20, PI-LL>10) on these changes was also analyzed. Statistical significance set at p<0.05. <h3>RESULTS</h3> There were 192 patients assessed. 179 patients had thoracolumbar (TL) deformity; TPA>20 (N=46), PI-LL>10 (N=55), and SVA>50 (N=78). In standing position, patients have a significant reduction in SVA post THA vs pre THA (34.09±42.69 vs 45.03±46.87, p=0.001) as a result of an increase in PT (15.7±9.74 ᵒ vs 14.6±9.88ᵒ,p=0.028), without significant changes in spinal alignment parameters including lumbar lordosis (-51.26±14.59 vs -50.26±14.87, p=0.092), thoracic kyphosis (35.98±12.72 vs 35.40±13.16, p=0.180), sacral slope (38.15±10.77 vs 38.83±11.31, p=0.205), T1 pelvic angle (14.22±9.94 vs 14.51±10.13, p=0.053) and PI-LL mismatch (2.59±14.61 vs 3.35±14.92, p=0.183). This change in ST_SVA was larger in patients with TL deformity, specifically in those with SVA>50 (61.29±45.69 vs 89.48±35.91, p=0.001), in PI-LL > 10 (59.08±45.49 vs 73.36±48.50, p=0.001) and in TPA>20 subsets (62.14±49.94 vs 82.28±49.55, p=0.001). When moving from ST to SE, the ΔPT was reduced post THA (16.70±15.27ᵒ vs 20.85±17.27ᵒ, p=0.001) in addition to a smaller SE_PT vs pre-THA (32.41±14.47 vs 35.46±14.20, p=0.006). <h3>CONCLUSIONS</h3> Post Total Hip Arthroplasty (THA), patients demonstrated an increased recruitment of pelvic retroversion to achieve a better global balance by reduction in standing SVA. This compensation was achieved solely by greater mobility of their hip and pelvis, and without a significant change in spinal alignment. ST_SVA reduction was more pronounced in patients with thoracolumbar (TL) spinal deformity (SVA>50, TPA>20, PI-LL>10). On the converse, PT was reduced in sitting (SE) post-THA compared to pre-THA, and the compensatory change in PT was also reduced between ST and SE as a result of restoration of hip flexion. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

146. A novel vertebral numbering system for identifying congenital anomalies of the spine using full spine radiographs with the EOS imaging system

<h3>BACKGROUND CONTEXT</h3> The numbering of vertebral transitional anatomy can be challenging and controversial. Disagreement exists on how to best report anomalous vertebra and which imaging modality (CT, MRI, X-ray, etc) is most consistent. For these reasons, there is often a discrepancy in the numbering of transitional levels between radiologists and surgeons. Moreover, correlating levels identified intraoperatively by fluoroscopy with inconsistently numbered vertebrae on preoperative MRI or CT is arduous. Errors in numbering can have devastating implications for patients. A simple and accurate vertebral numbering system that can be applied to routine imaging is needed. <h3>PURPOSE</h3> The purpose of this study was to describe a novel and more simplified vertebral numbering system that can be used amongst surgeons and radiologists. <h3>STUDY DESIGN/SETTING</h3> A retrospective imaging study analyzing full-length spine X-rays was performed with the approval of a Colorado Multiple Institutional Review Board (COMIRB protocol:17-1920). <h3>PATIENT SAMPLE</h3> A total of 5,422 images were obtained that included all adult patients who presented to the Spine Center at the University of Colorado and obtained full-spine X-rays using the EOS imaging system between January 31st of 2018 and March 31st of 2020. Images from the same patient at multiple time points were excluded and 3,250 unique patient images were included in our study. After the initial period of data collection, 103 images were excluded from the final analysis due to poor image quality or missing image files. <h3>OUTCOME MEASURES</h3> Total presacral mobile segments were identified and counted using 24 as the number found in conventional spinal anatomy. The total number of ribs were counted for each patient including hypoplastic ribs, and the level of the first-ribbed vertebrae and last-ribbed vertebrae were recorded. <h3>METHODS</h3> Image analysis was conducted by five experienced researchers. The results were reviewed and verified by the senior authors. Any disagreements were reviewed and resolved by two board-certified musculoskeletal radiologists. Final results were evaluated and a novel vertebral numbering system with the lowest probability of error was agreed upon. <h3>RESULTS</h3> In our study cohort, 91.1% (2,868/3,147) demonstrated the conventional 24 presacral mobile segments, whereas 3.3% (104) had 23 presacral mobile segments, 5.5% (174) had 25, and 0.03% (1) had 26. Transitional anatomy, as defined by a number of presacral segments other than 24, was noted in 8.8% (279) of the total number of patients. Within this same group, the majority (94.6%; 2,976) had 12 ribs (including hypoplastic ribs), 4.5% (143) had 11 ribs, and 0.88% (28) had 13 ribs. Just 3.5% (112) had incomplete or hypoplastic ribs. Furthermore, 1.8% (56) of patients had both transitional anatomy and an abnormal number of ribs, with the pattern of transitional anatomy and 11 ribs being the most common combination identified. Considering the first nonribbed vertebrae as the first lumbar vertebrae yielded the lowest probability of a numbering error. <h3>CONCLUSIONS</h3> We are proposing a novel vertebral numbering system that yields the lowest probability of error in reporting anomalous anatomy which can be applied to routine cervical, thoracic, and lumbar radiographs. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

143. Reliability of semi-automated spinal measurement software

<h3>BACKGROUND CONTEXT</h3> In the treatment of patients with adult spinal deformity, analysis of spinopelvic balance is essential in determining treatment options. This includes pelvic tilt (PT) and incidence (PI), lumbar lordosis (LL), and the sagittal vertical axis (SVA). Historically, the measurement of radiographs was done by hand with poor to moderate inter-observer reliability. More recently digital PACS tools provided improved accuracy and reliability, with the latest software semi-automating this process with a promise of increased efficiency. <h3>PURPOSE</h3> To our knowledge, no studies have examined the inter-observer reliability of semi-automated PACS software. This study aims to compare the reliability of this software versus PACS to determine if the improved efficiency occurs at the cost of reliability. <h3>Methods</h3> Full spine X-rays were retrospectively reviewed from 25 patients older than 18 years seen at a tertiary medical center between 2014 and 2017. Patients were included if they had greater than 5cm of sagittal imbalance, without prior surgical spinal fusion and/or instrumentation. Spinopelvic parameters were measured in two radiographic programs: one with basic, non-spine specific measurement tools (eUnity, Client Outlook, Waterloo, Canada); and a second with spine-specific measurement tools that semi-automate the measurement of these parameters (Sectra, Sectra AB, Linköping, Sweden). Balance parameters included SVA, PI, PT, and LL. Two authors re-measured radiographs after a 6-month interval and results were compared to original measurements. Data were compared by examining inter-rater and inter-program reliability using interclass correlation coefficient (ICC). We hypothesized that modern semi-automated software, with its promise of increased measurement efficiency, would maintain reliable results. <h3>Results</h3> The subjects' mean age was 67.9 +/- 13.8 years old, and 32% were male. The inter-program reliability was strong, with ICC values greater than 0.91 for each parameter. Similarly, there was strong inter-observer reliability with ICC values greater than 0.88. Delayed re-measurement also showed strong reliability with ICC values greater than 0.90 (p < 0.001 for all measurements). <h3>Conclusions</h3> There is excellent inter-observer and inter-program reliability between the basic PACS and semi-automated programs. These data demonstrate that the purported efficiency of semi-automated measurement programs does not come at the cost of measurement reliability. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Influencia del desequilibrio sagital en el resultado clínico de la vertebroplastia en pacientes con fractura por compresión vertebral osteoporótica

Background and objectivesThe correlation between sagittal balance of the spine and clinical outcome after vertebroplasty (VP) in patients with osteoporotic vertebral compression fractures (OVCF) is poorly investigated. We analysed the clinical outcome of patients with OVCF undergoing VP taking into account sagittal balance. Material and methodThe primary endpoint was the change in axial back pain, disability and health-related quality-of-life using Visual Analogue Scale (VAS), Oswestry Disability Index (ODI) and SF-36, respectively, in correlation to the parameters that define sagittal balance (SVA). Radiographic assessment included full spine standing lateral films. Imaging and clinical data were collected pre- and post-procedure at 1, 3 and 12 months. Results51 patients were included presenting a total of 113 OVCF. 30 patients (60.7%) had multiple OVCF. Comparing the evolution of VAS and ODI throughout the follow-up it does not seem that there are significant differences in their behaviour between the SVA>50mm and the SVA<50mm groups (p>0.05). On the contrary, pre-VP SF-36 scores showed worst results in the SVA>50mm group in the physical functioning (PF) section (p<0.05) and in the physical component score (PCS) (p<0.05). These differences were maintained until 3 months of follow-up in the case of the PCS and until the end of follow-up in the case of the PF (p<0.05). ConclusionsPatients with a SVA>50mm showed a slower recovery of their quality-of-life after VP for OVCF, but without significant differences with respect to pain or disability, when compared patients with SVA<50mm.

Trunk Kinematics Using Musculoskeletal Modeling During Range Of Motion Tasks

A spine model can be used to predict post-spinal fusion motion needed to perform physical activities in individuals with scoliosis. Full body lumbar spine (FBLS) model (Raabi and Chaudhari, 2016) allows for modeling lumbar spine and pelvis movement and was validated for jogging. However, like other existing adult spine models, FBLS model does not allow for a motion providing thoracic spine. PURPOSE: To adapt the FBLS model for simulating thoracic, lumbar and pelvis motion during trunk rotation in all 3 planes of motion. METHODS: Since T12-L1 in FBLS model is designed as a dependent joint (axial rotation analogous to L5-S1), the constraints between torso and lumbar spine were removed and modified to allow 3 degrees of freedom for T12-L1. Model ROM were adjusted to match for expected ranges of the test tasks. Inverse kinematics (IK) were calculated for the adjusted model. Range of motion (ROM; max-min) at T12-L1 and L5-S1 joints from FBLS were compared to the 3D motion capture data of 3 healthy adults during maximal flexion-extension, lateral bending, and axial rotation tasks. RESULTS: Experimental data calculated for axial rotation for T12-L1 and L5-S1, respectively were 64.4 ± 3.8° and 30.0 ± 7.2° of flexion-extension, 40.8° ± 4° and 10.9° ± 4.7° of lateral bending, and 29.7° ± 3.6° and 13.9° ± 1.1°. While IK from FBLS were 2.4° ± 0.1 and 16.3° ± 2.0 of flexion-extension, 7.9° ± 0.7 and 1.5° ± 0.4° of lateral bending, and 32.7° ± 0.6° and 12.9° ± 4° of axial rotation for T12-L1 and L5-S1, respectively. T12-L1 joint motion from OpenSim and human data movement patterns did not corroborate in sagittal and frontal planes where a disconnection between thoracic and lumbar segments was noted. Subsequently, experimental data was significantly greater than IK for sagittal (mean difference: 96.3% and 45.7%) and frontal planes (80.6% and 86.2%) from FBLS and matched best for transverse plane (10.1% and 7.2%) for T12-L1 and L5-S1, respectively. CONCLUSION: The existing FBLS model shows reasonable promise to be adapted for ROM tasks in transverse plane motion but not for sagittal and frontal planes to model trunk motions greater than those expected in jogging.

May bending radiographs be replaced by recumbent CT scans in patients with adolescent idiopathic scoliosis?

PurposeThere is no data that show if it is possible to determine if a curve is structural or non-structural or to assess flexibility of an adolescent idiopathic scoliosis (AIS) by recumbent images like a CT scan (CTS) instead of bending radiographs (BR). We investigated if the results of BR may be compared to those of CTS.MethodsWe retrospectively analyzed prospectively collected data of patients with AIS in whom a selective spinal fusion was performed and in whom a CTS, BR, and full spine x-rays were made preoperatively. We measured the Cobb angles of the main and the minor curve in full spine x-ray, BR, and CTS.ResultsAfter applying inclusion and exclusion criteria, 39 patients were included. We found a strong correlation (r = 0.806, p < 0.01) between the Cobb angle of the main curve in BR and the Cobb angle of the main curve in the CTS and between the Cobb angle of the minor curve in BR and the Cobb angle of the minor curve in the CTS (r = 0.601, p < 0.01). All patients with a minor curve of less than 25 degrees in the BR had a Cobb angle of less than 35 degrees in the CTS.ConclusionSpinal curves showed a significant correlation between bending radiographs and recumbent images (CTS). In our group of patients, a Cobb angle of the minor curve of less than 35 degrees in the CTS indicated that this minor curve was non-structural.

Treatment of one-level degenerative lumbar spondylolisthesis with severe stenosis by oblique lateral interbody fusion: Clinical and radiological results after a minimal 1-year follow-up

ObjectiveTo evaluate the clinical and radiological outcomes of patients undergoing one-level oblique lumbar interbody fusion (OLIF) combined with posterolateral fusion (PLF) with pedicle screws for the treatment of degenerative lumbar spondylolisthesis (DS) with a minimum follow-up of 1 year. MethodsA retrospective analysis of prospectively collected data was performed. Patients who underwent combined OLIF and PLF between March 2013 and December 2019 were considered for study eligibility. Patients were evaluated using the Oswestry Disability Index (ODI) and the Short Form-12 (SF-12) (physical PCS, mental MCS), self-evaluation of pain with a Visual Analog Scale (VAS) and walking distance. Compensation and sagittal balance were assessed using the Gille classification by full spine stereoradiography (EOS Imaging, Paris, France). Mechanical complications were also collected. ResultsA total of 131 patients were included (mean (SD) age: 64.2 ± 10.4 years), and 127 patients were evaluated after a mean follow-up of 22 ± 12.3 months. The mean ODI at the last follow-up was 13.8 ± 12.9% (gain of 32.3 ± 15.5%; p < 0.0001), the mean PCS was 45.6 ± 7.7 (gain of 12.6 ± 9.8) and the mean MCS was 43.9 ± 11.9 (gain of 5.3 ± 13.5) (p < 0.0001). Ten patients (7.6%) had adjacent segment syndrome, and there was one vertebral body fracture. Patients with preoperative imbalance (SVA > 40 mm) had a significant improvement in SVA of 19.8 ± 32 mm (p = 0.025). Sagittal imbalance (Gille type 3) was not associated with a change in postoperative functional score (p = 0.52). ConclusionsOLIF improved functional scores at 1 year, with excellent outcomes in 80% of our patients with a low morbidity. Sagittal imbalance did not adversely affect the clinical outcomes. Level of evidence4 (cohort study).

Equivalent Dose and Risk of Exposure Induced Cancer Death of Different Organs due to Various Image Techniques of EOS Imaging System.

Background: Euronext Paris Advanced Orthopedic Solutions (EOS) system is a new radiography system, capable of obtaining two-dimensional and three-dimensional images from bony structures in the body. Objective: The aim of this study is to estimate equivalent dose and the risk of exposure induced cancer death (REID) in different organs of body due to EOS imaging system.Material and Methods: In this experimental study, totally 120 patients were evaluated for various imaging techniques of lower limb, full spine and whole body. Equivalent dose and REID for colon, liver, lung, stomach, breast, bladder, ovary, blood cells (leukemia) and other organs were calculated using PCXMC software (version 2.0.1.2) based on Monte Carlo simulation of X-ray and human phantoms. The data on imaging technique, including age, sex, kVp, dose area product (DAP), mA, focal to detector distance were introduced as the input of PCXMC.Results: The maximum equivalent dose (mSv) due to EOS imaging system, was estimated for the bladder 0.240±0.066 for the full body technique and 0.240±0.093 for the lower limb technique, respectively, in both males and females. The maximum organ REID (incidence per million) due to EOS imaging system was estimated for lungs as 2.59±1.0 and 2.53±0.9, for the full body technique in both males and females, respectively. Conclusion: Generally, the equivalent dose and REID by EOS imaging system in different organs of body is low due to the low radiation dose received by the body in different techniques and views.

Comparison of 3D and 2D characterization of spinal geometry from biplanar X-rays: a large cohort study.

Biplanar X-ray system providing anteroposterior and sagittal plane with an ultra-low radiation dose and in weight-bearing position is increasingly used for spine imaging. The original three-dimensional (3D) reconstruction method from biplanar X-rays has been widely used for clinical parameters, however, the main issue is that manual adjustments of the 3D model was quite time-consuming and limited to thoracolumbar spine. A quasi-automated 3D reconstruction method of the spine from cervical vertebra to pelvis was proposed, which proved fast and accurate in 57 patients with adolescent idiopathic scoliosis. The aim of this study was to compare the newly developed technique of quasi-automatic 3D measurement with classical 2D measurements in a large cohort. A total of 494 adults with biplanar EOS X-ray scanning were included in this study and divided into health and deformity group according to the presence of spinal deformity. The proposed method of quasi-automatic 3D measurement was applied to all these subjects. The radiographic parameters included: thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), sagittal vertical axis (SVA), T1 pelvic angle (TPA) in sagittal plane, and cobb angle in coronal plane. Comparison was made between quasi-automatic and manual measurement. The mean age was 53.7±19.9 years old. In the whole population, the mean differences between the two methods were 3.9° for TK (30.5°±9.9° vs. 26.5°±9.3°, P<0.001), -5.2° for LL (-47.5°±11.2° vs. -42.4°±11.0°, P<0.001), 3.6° for PI (46.9°±10.3° vs. 43.9°±10.3°, P<0.001), -0.2° for PT (11.9°±7.7° vs. 12.0°±8.2°, P=0.328), -2.1 mm for SVA (15.7±26.2 vs. 17.8±26.3 mm, P=0.221) and -1.1° for TPA (9.0°±7.6° vs. 10.1°±7.8°, P=0.051). The deformity group had similar mean differences with the asymptomatic group with the values ranged from -4.1° to 3.8° for sagittal parameters. The mean differences of Cobb angle were 1.9° for patients with Cobb angle <30° and 2.3° for patients with Cobb angle >30°, respectively. Correlation analysis showed r2 for all clinical parameters ranged from 0.667 to 0.923. On average, the new method takes 5 minutes to compute all the parameters for one case. In conclusion, this ergonomic and efficient quasi-automatic method for full spine proved fast and accurate measurement in a large population, which showed great potential in extensive clinical application.

Comparison of the Outcomes of Percutaneous Endoscopic Interlaminar Lumbar Discectomy and Open Lumbar Microdiscectomy at the L5-S1 Level

Although many studies have compared full endoscopic spine surgery and open spine surgery, few have compared the outcomes of percutaneous endoscopic interlaminar lumbar discectomy (PEILD) and open lumbar microdiscectomy (OLM) at the L5-S1 level. We compared the clinical, surgical, and radiological outcomes of patients with disc herniation at the L5-S1 level who underwent either PEILD, or OLM, performed by a single surgeon with novice-level proficiency. Observational, retrospective matched cohort design. An analysis of clinical data was performed at a single center, collected from September 2012 to August 2016. The study enrolled 56 patients who underwent discectomy at the L5-S1 level, with a minimum one-year follow-up. Patients were allocated to 2 groups: a PEILD group (n = 27; September 2014 to August 2016), or an OLM group (n = 29; September 2012 to August 2014). Clinical, surgical, and radiological outcomes were retrospectively evaluated. Baseline characteristics including age, gender, past medical history, body mass index, preoperative symptom, and preoperative radiological findings did not differ significantly between the groups. Further, overall clinical outcomes including back and leg pain; surgical outcomes including blood loss, complication rate, and recurrence rate; and radiological outcomes including degree of decompression, disc height, and sagittal alignment were not different significantly between the 2 groups.However, the PEILD group showed significant advantages including lower immediate postoperative back pain (mean 1.44 [95% confidence interval (CI), 1.16-1.72] versus 2.41 [95% CI, 2.14-2.69], P < 0.001), favorable immediate postoperative Odom's criteria (excellent 57.14% versus 24.14%, P = 0.025), shorter operation time (mean 63.89 ±17.99 minutes versus 109.66 ±31.42 minutes, P < 0.001), shorter hospital stay (3.15 [95% CI, 2.21-4.09] days versus 5.72 [95% CI, 3.29-8.16] days, P < 0.001), and rapid return to work (15.67 [95% CI, 12.64-18.69] days versus 24.31 [95% CI ,19.97-28.65] days, P = 0.001). Due to its retrospective nature, it was not possible to control for all variations. Moreover, the number of patients in the final cohort was relatively small. Our findings indicate that the PEILD group achieved better perioperative outcomes despite no significant intergroup difference in mid-term clinical and radiological outcomes.