SAM

Quasi-automatic early detection of progressive idiopathic scoliosis from biplanar radiography: a preliminary validation

COURTOIS, Isabelle — Tue, 01 Jan 2019 00:00:00 GMT

Quasi-automatic early detection of progressive idiopathic scoliosis from biplanar radiography: a preliminary validation COURTOIS, Isabelle; EBERMEYER, Eric; ABELIN-GENEVOIS, Kariman; KIM, Youngwoo; LANGLAIS, Tristan; VIALLE, Raphaël; ASSI, Ayman; GHANEM, Ismat; DUBOUSSET, Jean; SKALLI, Wafa; GAJNY, Laurent; VERGARI, Claudio Purpose To validate the predictive power and reliability of a novel quasi-automatic method to calculate the severity index of adolescent idiopathic scoliosis (AIS). Methods Fifty-five AIS patients were prospectively included (Age: 10-15, Cobb: 16° ± 4°). Patients underwent low-dose biplanar x-rays and a novel fast method for 3D reconstruction of the spine was performed. They were followed until skeletal maturity (stable patients) or brace prescription (progressive patients). The severity index was calculated at the first exam, based on 3D parameters of the scoliotic curve, and it was compared with the patient’s final outcome (progressive or stable). Three operators have repeated the 3D reconstruction twice for a subset of 30 patients to assess reproducibility (through Cohen’s kappa and intraclass correlation coefficient). Results 85% of the patients were correctly classified as stable or progressive by the severity index, with a sensitivity of 92% and specificity of 74%. Substantial intra-operator agreement and good inter-operator agreement were observed, with 80% of the progressive patients correctly detected at the first exam. The novel severity index assessment took less than 4 minutes of operator time. Conclusions The fast and semi-automatic method for 3D reconstruction developed in this work allowed for a fast and reliable calculation of the severity index. The method is fast and user friendly. Once extensively validated, this severity index could allow very early initiation of conservative treatment for progressive patients, thus increasing treatment efficacy and therefore reducing the need for corrective surgery.

Biomechanical Evaluation of Intercostal Muscles in Healthy Children and Adolescent Idiopathic Scoliosis: A Preliminary Study

PIETTON, Raphaël — Fri, 01 Jan 2021 00:00:00 GMT

Biomechanical Evaluation of Intercostal Muscles in Healthy Children and Adolescent Idiopathic Scoliosis: A Preliminary Study PIETTON, Raphaël; DAVID, Mercedes; HISAUND, Alisa; LANGLAIS, Tristan; SKALLI, Wafa; VIALLE, Raphaël; VERGARI, Claudio Spine deformity during adolescent idiopathic scoliosis can induce a rib-cage deformity. This bone deformity can have direct consequences on the chest-wall muscles, including intercostal muscles, leading to respiratory impairments in individuals with severe cases. The aim of this study was to determine whether shear-wave elastography can be used to measure intercostal-muscle shear-wave speed (SWS) in healthy children and those with adolescent idiopathic scoliosis (AIS). Nineteen healthy participants and 16 with AIS took part. SWS measurements were taken by three operators, twice each. Average SWS was 2.3 ± 0.4 m/s, and inter-operator reproducibility was 0.2 m/s. SWS was significantly higher during apnea than in normal breathing (p < 0.01) in both groups. No significant difference was observed between groups in apnea or in normal breathing. Characterization of the intercostal muscles by ultrasound elastography is therefore feasible and reliable for children and adolescents with and without scoliosis.

Shear wave elastography of lumbar annulus fibrosus in adolescent idiopathic scoliosis before and after surgical intervention

CHANTEUX, Lucas — Wed, 01 Jan 2020 00:00:00 GMT

Shear wave elastography of lumbar annulus fibrosus in adolescent idiopathic scoliosis before and after surgical intervention CHANTEUX, Lucas; PIETTON, Raphaël; LANGLAIS, Tristan; VIALLE, Raphaël; SKALLI, Wafa; VERGARI, Claudio Abstract Objectives To determine lumbar intervertebral disc properties with shear wave elastography in adolescent idiopathic scoliotic (AIS) patients before and after surgery, and compare them with asymptomatic controls. Methods Twenty-five severe AIS patients with an indication for fusion surgery (15 ± 1.5 years old, the Cobb angle ranging between 40 and 93°) and fifty-nine asymptomatic adolescents (13 ± 2 years old) were included prospectively. Shear wave speed (SWS) was measured in the annulus fibrosus of L3-L4, L4-L5, and L5-S1 discs of each subject. In AIS patients, measurements took place before surgery, and 3 months (N = 13) or 1 year after (N = 12). Results No difference was observed between disc levels in any group. When pooling disc levels, SWS was significantly higher in preop AIS patients (4.0 ± 0.5 m/s) than in asymptomatic subjects (3.1 ± 0.5 m/s, p < 0.0001). SWS decreased 3 months postop (3.5 ± 0.3 m/s), and it decreased further towards normal values 1 year after (3.3 ± 0.4 m/s). SWS in preop AIS patients tended to decrease with the Cobb angle (Spearman’s rho = − 0.4, p = 0.05). Conclusion Shear wave elastography measurements showed that discs in AIS patients were altered relative to asymptomatic ones, and this alteration tended to normalize 1 year post fusion surgery. Further studies should aim at determining if bracing of mild scoliosis has an effect on disc properties. Key Points • Shear wave elastography shows alteration of annulus fibrosus in adolescent idiopathic scoliosis. • Disc elastography tends to normalize 1 year after surgery.

Changes in quantitative elastography assessment of the adjacent lumbar disc after segmental fixation of the spine: a case description of a burst fracture of L4

PIETTON, Raphaël — Sat, 01 Jan 2022 00:00:00 GMT

Changes in quantitative elastography assessment of the adjacent lumbar disc after segmental fixation of the spine: a case description of a burst fracture of L4 PIETTON, Raphaël; VIALLE, Raphaël; LAURENT, Romain; SKALLI, Wafa; VERGARI, Claudio; LANGLAIS, Tristan Vertebral burst fractures are usually due to traumatic high-energy distraction of the vertebra. They often require pedicle screw fixation to stabilize the spine during the healing process but once the fusion of the fractured vertebra has occurred, the posterior fixation can be removed or shortened to restore part of the spinal mobility. The importance of sparing fusion levels to ensure optimal functional results has been demonstrated. In surgical planning, the rule is therefore to ensure the osteosynthesis stability while limiting the number of levels included. Immobilization or fixation of a vertebral segment may be responsible for degeneration of the intervertebral disc and in case of surgical treatment the adjacent disc. Therefore, we can ask whether removal of a vertebral fixation could decrease the stress on adjacent segments. Ultrasound shearwave elastography is a new innovative and non-invasive technique allowing evaluation of soft tissue’s elastic modulus through the measurement of shear wave speed (SWS). This non-invasive imaging method has shown its added value in breast or in liver oncology and, more recently, in musculoskeletal pathologies assessment. In particular, Langlais et al. found that SWS measured in annulus fibrosus was significantly higher in progressive adolescent idiopathic scoliosis than in asymptomatic population, which is associated with a stiffer tissue. The same authors defined a corridor of normality (2.3–3.7 m/s) for the asymptomatic population and observed that annulus SWS tended to normalize 1 year after fusion surgery in severe adolescent idiopathic scoliosis. The aim of this case was to analyze the effect of removing the posterior fixation in a case of burst fracture on the mechanical properties of the bridged and adjacent intervertebral discs.

Evidence of spinal stiffening following fusionless bipolar fixation for neuromuscular scoliosis: a shear wave elastography assessment of lumbar annulus fibrosus

GAUME, Mathilde — Wed, 01 Nov 2023 00:00:00 GMT

Evidence of spinal stiffening following fusionless bipolar fixation for neuromuscular scoliosis: a shear wave elastography assessment of lumbar annulus fibrosus GAUME, Mathilde; LOISELET, Klervie; CHEKIR, Hedi; LANGLAIS, Tristan; BODDAERT, Nathalie; STRICKER, Sarah; PANNIER, Stéphanie; SKALLI, Wafa; MILADI, Lotfi; VERGARI, Claudio Objectives There are no established criteria for stiffness after fusionless surgery for neuromuscular scoliosis (NMS). As a result, there is no consensus regarding the surgical strategy to propose at long-term follow-up. This study reports the first use of shear wave elastography for assessing the mechanical response of lumbar intervertebral discs (IVDs) after fusionless bipolar fixation (FBF) for NMS and compares them with healthy controls. The aim was to acquire evidence from the stiffness of the spine following FBF. Patients and methods Nineteen NMS operated on with FBF (18 ± 2y at last follow-up, 6 ± 1 y after surgery) were included prospectively. Preoperative Cobb was 89 ± 20° and 35 ± 1° at latest follow-up. All patients had reached skeletal maturity. Eighteen healthy patients (20 ± 4 y) were also included. Shear wave speed (SWS) was measured in the annulus fibrosus of L3L4, L4L5 and L5S1 IVDs and compared between the two groups. A measurement reliability was performed. Results In healthy subjects, average SWS (all disc levels pooled) was 7.5 ± 2.6 m/s. In NMS patients, SWS was significantly higher at 9.9 ± 1.4 m/s (p < 0.05). Differences were significant between L3L4 (9.3 ± 1.8 m/s vs. 7.0 ± 2.5 m/s, p = 0.004) and L4L5 (10.3 ± 2.3 m/s vs. 7.1 ± 1.1 m/s, p = 0.0006). No difference was observed for L5S1 (p = 0.2). No correlation was found with age at surgery, Cobb angle correction and age at the SWE measurement. Conclusions This study shows a significant increase in disc stiffness at the end of growth for NMS patients treated by FBF. These findings are a useful adjunct to CT-scan in assessing stiffness of the spine allowing the avoidance of surgical final fusion at skeletal maturity.

Spontaneous induced bone fusion in minimally invasive fusionless bipolar fixation in neuromuscular scoliosis: a computed tomography analysis

GAUME, Mathilde — Mon, 01 May 2023 00:00:00 GMT

Spontaneous induced bone fusion in minimally invasive fusionless bipolar fixation in neuromuscular scoliosis: a computed tomography analysis GAUME, Mathilde; LANGLAIS, Tristan; LOISELET, Klervie; PANNIER, S.; SKALLI, Wafa; VERGARI, Claudio; MILADI, Lotfi Purpose Posterior spinal fusion (PSF) at skeletal maturity is still the gold standard in children with neuromuscular scoliosis (NMS) who underwent fusionless surgery. The aim of this computed tomography (CT) study was to quantify the spontaneous bone fusion at the end of a lengthening program by minimally invasive fusionless bipolar fixation (MIFBF), that could avoid PSF. Methods NMS operated on with MIFBF from T1 to the pelvis and at final lengthening program were included. CT was performed at least five years postoperatively. The autofusion was classified as completely or not fused at the facets joint (on both coronal and sagittal plane, right and left side, from T1 to L5), and around the rods (axial plane, right and left side, from T5 to L5). Vertebral body heights were assessed. Results Ten patients were included (10.7y ± 2 at initial surgery). Mean Cobb angle was 82 ± 20 preoperatively and 37 ± 13 at last follow-up. CT were performed on average 6.7y ± 1.7 after initial surgery. Mean preoperative and last follow-up thoracic vertebrae height were respectively 13.5 mm ± 1.7 and 17.4 mm ± 1.7 (p < 0.001). 93% facets joints were fused (out of 320 analyzed joints), corresponding to 15/16 vertebral levels. Ossification around the rods was observed in 6.5±2.4 levels out of 13 in the convex side, and 4.2 ± 2.2 in the concave side (p = 0.04). Conclusions This first computed quantitative study showed MIFBF in NMS preserved spinal growth, while it induced 93% of facet joints fusion. This could be is an additional argument when questionning the real need for PSF at skeletal maturity.

Spinal axial torque assessment after surgical correction in adolescent idiopathic scoliosis: a new approach to 3D barycentremetry and mass distribution based on biplanar radiographs

LANGLAIS, Tristan — Thu, 01 Feb 2024 00:00:00 GMT

Spinal axial torque assessment after surgical correction in adolescent idiopathic scoliosis: a new approach to 3D barycentremetry and mass distribution based on biplanar radiographs LANGLAIS, Tristan; SKALLI, Wafa; DU CLUZEL, Xavier; MAINARD, Nicolas; GEORGE, Samuel; GAJNY, Laurent; VIALLE, Raphaël; DUBOUSSET, Jean; VERGARI, Claudio Purpose Barycentremetry in adolescent idiopathic scoliosis (AIS) allows the distribution of masses and their loading of the spine to be studied. In particular, the axial torque on the spine has been studied in AIS, but not after surgical correction. Spinal axial torque was studied in AIS before and after surgery. Methods All AIS (Lenke 1 and 3) who underwent posterior spinal fusion surgery at our center in 2019 were included retrospectively. AIS underwent frontal and sagittal biplanar radiographs in the free-standing position before surgery, 4 months after surgery, and at the last follow-up. Their spine and external envelope were reconstructed with validated methods. Spinal axial torque at the apex and the upper and lower end vertebra was calculated. Finally, the preoperative and postoperative values were compared to a previously published reference corridor for asymptomatic subjects. Results Twenty-nine patients were included (54 ± 11° Cobb angle, 15 ± 2 years old at surgery). The surgical procedure decreased the Cobb angle by 36° ± 11° and decreased the spinal axial torque at the upper end vertebra by 2.5 N/m (95% CI = [1.9; 3]; p < 0.001), at the apex by 0.6 N/m (95% CI = [0.4; 1]; p = 0.004), at the lower end vertebra by 2 N/m (95% CI = [1.5; 2.8]; p < 0.001). Compared to 95th percentile of torque, which was previously evaluated in asymptomatic subjects, more than 90% of patients had higher values at the upper and lower end vertebrae before surgery. Postoperatively, 62% of patients still had higher torque at the upper end vertebra than asymptomatic subjects, while only 38% patients showed abnormal values at the lower junction. Conclusion Results of this study confirm that AIS patients show abnormally high spinal axial torque, especially at the end vertebrae, and that this parameter is normalized postoperatively for only a small number of patients.

Assessment of malalignment at early stage in adolescent idiopathic scoliosis: a longitudinal cohort study

LANGLAIS, Tristan — Thu, 01 Feb 2024 00:00:00 GMT

Assessment of malalignment at early stage in adolescent idiopathic scoliosis: a longitudinal cohort study LANGLAIS, Tristan; VERGARI, Claudio; ROUGEREAU, Grégoire; GAUME, Mathilde; GAJNY, Laurent; ABELIN-GENEVOIS, Kariman; BERNARD, Jean-Claude; HU, Zongshan; CHENG, Jack Chun Yiu; CHU, Winnie Chiu Wing; ASSI, Ayman; KARAM, Mohamad; GHANEM, Ismat; BASSANI, Tito; GALBUSERA, Fabio; SCONFIENZA, Luca Maria; BRAYDA-BRUNO, Marco; COURTOIS, Isabelle; EBERMEYER, Eric; VIALLE, Raphaël; DUBOUSSET, Jean; SKALLI, Wafa Introduction Our objective was to assess abnormalities of the odontoid-hip axis (OD-HA) angle in a mild scoliotic population to determine whether screening for malalignment would help predict the distinction between progressive and stable adolescent idiopathic scoliosis (AIS) at early stage. Materials and methods All patients (non-scoliotic and AIS) underwent a biplanar X-ray between 2013 and 2020. In AIS, inclusion criteria were Cobb angle between 10° and 25°; Risser sign lower than 3; age higher than 10 years; and no previous treatment. A 3D spine reconstruction was performed, and the OD-HA was computed automatically. A reference corridor for OD-HA values in non-scoliotic subjects was calculated as the range [5th–95th percentiles]. A severity index, helping to distinguish stable and progressive AIS, was calculated and weighted according to the OD-HA value. Results Eighty-three non-scoliotic and 205 AIS were included. The mean coronal and sagittal OD-HA angles in the non-scoliotic group were 0.2° and −2.5°, whereas in AIS values were 0.3° and −0.8°, respectively. For coronal and sagittal OD-HA, 27.5% and 26.8% of AIS were outside the reference corridor compared with 10.8% in non-scoliotic (OR = 3.1 and 3). Adding to the severity index a weighting factor based on coronal OD-HA, for thoracic scoliosis, improved the positive predictive value by 9% and the specificity by 13%. Conclusion Analysis of OD-HA suggests that AIS patients are almost three times more likely to have malalignment compared with a non-scoliotic population. Furthermore, analysis of coronal OD-HA is promising to help the clinician distinguish between stable and progressive thoracic scoliosis.

Sagittal plane assessment of manual concave rod bending for posterior correction in adolescents with idiopathic thoracic scoliosis (Lenke 1 and 3)

LANGLAIS, Tristan — Sat, 01 Jul 2023 00:00:00 GMT

Sagittal plane assessment of manual concave rod bending for posterior correction in adolescents with idiopathic thoracic scoliosis (Lenke 1 and 3) LANGLAIS, Tristan; BOUY, Alois; ELOY, Gauthier; MAINARD, Nicolas; SKALLI, Wafa; VERGARI, Claudio; VIALLE, Raphael Objectives The objectives of this study were to evaluate the repeatability and reproducibility of a method for measuring freehand rod bending and to analyze the relationship between the rod's bend and the resulting sagittal correction. Materials and methods All the children who underwent correction by posterior translation using pedicle screws at all levels were included prospectively in 2018 and 2019. The rod's sagittal parameters were measured retrospectively by three independent surgeons on two separate occasions using the same protocol. After the rods were bent but before they were inserted, the surgeon traced the contours of the rods on a sheet of paper that was later scanned and analyzed semiautomatically. The spinal parameters were calculated based on biplanar radiographs taken preoperatively, postoperatively and at the final follow-up visit. Patients who had less than 10° thoracic kyphosis (T5–T12) made up the “Lenke N−” subgroup. Results Thirty patients were included (14 of whom were Lenke N−) who had a Cobb angle of 59.2 ± 11.3° preoperatively and 13.3 ± 8.4° postoperatively (p < 0.00001). The inter- and intrarater ICC for the rod measurements were > 0.9 (excellent). The mean kyphosis of the concave rod was 48.4 ± 5.7° (38.3–60.9°). The mean change in T5–T12 kyphosis was 9.7 ± 10.8° (−14.3–30.8°) (p < 0.0001) in the entire population, while it was 17.7 ± 7.1° (5.5–30.8°) (p < 0.0001) in the Lenke N− subgroup. The change in thoracic kyphosis was positively correlated with the kyphosis of the concave rod (rho = 0.52; p = 0.003). Conclusion This study found excellent reproducibility and repeatability of measuring freehand rod bending. The kyphosis applied to the concave rod is positively correlated to the change in the resulting kyphosis and made it possible to restore satisfactory thoracic kyphosis.

Estimating pulmonary function after surgery for adolescent idiopathic scoliosis using biplanar radiographs of the chest with 3D reconstruction

PIETTON, Raphaël — Sat, 01 Jan 2022 00:00:00 GMT

Estimating pulmonary function after surgery for adolescent idiopathic scoliosis using biplanar radiographs of the chest with 3D reconstruction PIETTON, Raphaël; BOULOUSSA, Houssam; LANGLAIS, Tristan; TAYTARD, Jessica; BEYDON, Nicole; SKALLI, Wafa; VERGARI, Claudio; VIALLE, Raphaël Aims This study addressed two questions: first, does surgical correction of an idiopathic scoliosis increase the volume of the rib cage, and second, is it possible to evaluate the change in lung function after corrective surgery for adolescent idiopathic scoliosis (AIS) using biplanar radiographs of the ribcage with 3D reconstruction? Methods A total of 45 patients with a thoracic AIS which needed surgical correction and fusion were included in a prospective study. All patients underwent pulmonary function testing (PFT) and low-dose biplanar radiographs both preoperatively and one year after surgery. The following measurements were recorded: forced vital capacity (FVC), slow vital capacity (SVC), and total lung capacity (TLC). Rib cage volume (RCV), maximum rib hump, main thoracic curve Cobb angle (MCCA), medial-lateral and anteroposterior diameter, and T4-T12 kyphosis were calculated from 3D reconstructions of the biplanar radiographs. Results All spinal and thoracic measurements improved significantly after surgery (p < 0.001). RCV increased from 4.9 l (SD 1) preoperatively to 5.3 l (SD 0.9) (p < 0.001) while TLC increased from 4.1 l (SD 0.9) preoperatively to 4.3 l (SD 0.8) (p < 0.001). RCV was correlated with all functional indexes before and after correction of the deformity. Improvement in RCV was weakly correlated with correction of the mean thoracic Cobb angle (p = 0.006). The difference in TLC was significantly correlated with changes in RCV (p = 0.041). It was possible to predict postoperative TLC from the postoperative RCV. Conclusion 3D rib cage assessment from biplanar radiographs could be a minimally invasive method of estimating pulmonary function before and after spinal fusion in patients with an AIS. The 3D RCV reflects virtual chest capacity and hence pulmonary function in this group of patients.