Variation of cervical sagittal alignment parameters according to age and pelvic incidence in degenerative spinal deformity patients.

INTRODUCTION: In asymptomatic subjects, variations of cervical sagittal alignment parameters according to age and spinopelvic organization have been reported. A large range of compensation phenomena has been observed in degenerative spinal deformity in order to maintain horizontal gaze, but it remains unclear how age and spinopelvic morphology could additionally influence cervical alignment. The aim of this observational retrospective study was to describe the distribution of cervical sagittal alignment parameters according to age and pelvic incidence in subjects with and without degenerative spinal deformity in order to precisely evaluate cervical compensation phenomena in adult spinal deformity (ASD). MATERIAL AND METHODS: Radiographs of 478 subjects (327 females and 151 males) were distributed into 235 asymptomatic and 243 deformed subjects. Occipito-cervical parameters were McGregor-C1, McGregor-C2, C1-C2 and occipito-C2 angles. The cervicothoracic inflection point (CTIP) was determined. Caudal cervical sagittal alignment parameters were: C2-C7 lordosis, C2-apex (superior arch), apex-CTIP (inferior arch), occipito-C3 and occipito-C4 angles, C7-slope and T1-slope. The distribution of parameters was analyzed using a Bayesian inference (significant when Pr > 0.975 or Pr < 0.025). Comparisons between asymptomatic and deformed subjects were done after matching on age (40-60 years; > 60 years) and on PI (< 45°; 45-60°; > 60°). RESULTS: Among occipito-cervical parameters, there was no significant change in McGregor-C1 angle. However, McGregor-C2 angle was significantly higher in the ASD group (Pr = 0.0029), with influence of age (Pr = 0.023), but PI influence. C1-C2 lordosis was significantly higher in the ASD group compared to the asymptomatic group (Pr < 0.0007), without influence of age or PI noticed. C2-C7 lordosis was also higher in the ASD group (Pr < 0.025) with a role of age and PI (Pr < 0.025). Cervical lordosis in the superior arch was significantly higher in the ASD group (Pr > 0.999), without influence of age or PI. In the inferior arch, the lordosis angle was not modified according to the group, but there was an influence of age (Pr < 0.0007). C7-slope and T1-slope were higher according the age group (Pr < 0.0012), without influence of the group or PI. CONCLUSION: This observational study highlights cervical sagittal alignment adaptations in degenerative spinal deformity, matched on age and pelvic incidence. The inferior cervical spine seemed to be modified with a higher lordosis, increasing with age responding to the age-related thoracic kyphosis increase. In addition to that, the superior cervical spine hyperextends more in adult degenerative deformity to maintain horizontal gaze. LEVEL OF EVIDENCE: III.

Variation of cervical sagittal alignment parameters according to gender, pelvic incidence and age.

PURPOSE: The aim was to describe radiographic cervical sagittal alignment variations according to age, gender and pelvic incidence (PI) and to investigate relationships with thoracic alignment. METHODS: A total of 2599 individuals (5-93 years) without spinal deformity were studied. Cranial cervical parameters were: McGregor slope, occipita-C2 angle, McGregor-C2 lordosis and C1-C2 lordosis. Caudal cervical parameters were: C2-C7, cranial arch and caudal arch lordosis and C7- and T1-slope. A Bayesian inference compared parameter distributions. Correlations with spinopelvic and global alignment parameters were investigated. RESULTS: Among cranial cervical parameters, variations of McGregor slope were non-significant. McGregor-C2 lordosis and C1-C2 lordosis were smaller in males and increased significantly during growth, whereas the occipito-C2 angle decreased (Pr > 0.95). The occipito-C2 angle was larger and McGregor-C2 lordosis was smaller in low PI (Pr > 0.95). Among caudal cervical parameters, C2-C7 lordosis and C7- and T1-slope were larger in males and increased after 50 years (Pr > 0.95). Lordosis changes were non-significant in the cranial arch, whereas values increased in the caudal arch after 35 years (Pr > 0.95). Caudal parameter differences were non-significant between PI groups. Strong correlations existed between C2-C7, caudal arch lordosis, C7-slope, T1-slope and thoracic kyphosis. The sagittal vertical axis C2 correlated with caudal arch lordosis and T1-slope (ρ > 0.5; Pr > 0.95). CONCLUSION: Cervical alignment parameters vary according to age, gender and PI. In the cranial cervical spine, changes occur mainly during growth. In the caudal cervical spine, lordosis increases in the caudal arch, which is related to thoracic kyphosis increase with age. The caudal cervical arch acts as a compensatory segment by progressive extension, allowing horizontal gaze.

Early dynamic changes within the spine following posterior fusion using hybrid instrumentation in adolescents with idiopathic scoliosis: a gait analysis study.

INTRODUCTION: In adolescent idiopathic scoliosis (AIS) patients, mechanical consequences of posterior spinal fusion within the spine remain unclear. Through dynamic assessment, gait analysis could help elucidating this particular point. The aim of this study was to describe early changes within the spine following fusion with hybrid instrumentation in adolescents with idiopathic scoliosis, using gait analysis MATERIALS AND METHODS: We conducted a single-centre prospective study including AIS patients scheduled for posterior spinal fusion (PSF) using hybrid instrumentation with sublaminar bands. Patients underwent radiographic and gait analyses preoperatively and during early postoperative period. Among gait parameters, motion of cervicothoracic, thoracolumbar and lumbosacral junctions was measured in the three planes. RESULTS: We included 55 patients (mean age 15 years, 84% girls). Fusion was performed on 12 levels and mean follow-up was 8 months. There was a moderately strong correlation between thoracolumbar sagittal motion and lumbosacral junction pre- and postoperatively (R = - 0.6413 and R = - 0.7040, respectively, all p < 0.001), meaning that the more thoracolumbar junction was in extension, the more lumbosacral extension movements decreased. There was a trend to significance between postoperative SVA change and thoracolumbar sagittal motion change (R = - 0.2550, p = 0.059). DISCUSSION: This is the first series reporting dynamic changes within the spine following PSF using hybrid instrumentation in AIS patients. PSF led to symmetrization of gait pattern. In the sagittal plane, we found that thoracolumbar extension within the fused area led to decreased extension at cervicothoracic and lumbosacral junctions. Even though consequences of such phenomenon are unclear, attention must be paid not to give a too posterior alignment when performing PSF for AIS patients.

Description of spine motion during gait in normal adolescents and young adults.

INTRODUCTION: Standing radiographs allow analysis of spinal segments and their relative positioning. However, it requires a specific positioning influencing spinal alignment. Knowledge of trunk movements when walking is therefore an essential step to evaluate dynamic sagittal balance. Our objective was to define spinal junction kinematics and their correlations during gait in a healthy population. METHOD: This is a prospective, single-center study. Between 2015 and 2017, 25 healthy volunteers were included. The measurements were taken in a motion analysis laboratory. Several kinematic parameters were studied, including spinal junction movements in the three planes and dynamic sagittal vertical axis (Dyn-SVA). Pearson correlation coefficients were calculated to determine the interactions between the spinal junctions. RESULTS: In the sagittal plane, the average amplitude of variation of the dyn-SVA was 25.5 cm (SD = 8.9). The average range of motion of the lumbosacral and thoracolumbar junction was approximately 3°, they operated in anti-phase during the gait cycle and were strongly correlated (r = -0.5069, p = 0.01). In the transverse plane, the anti-rotation of the upper body relative to the pelvis was mainly ensured by the opposite movements of the lumbosacral and thoracolumbar junction (r = 0.5689, p = 0.003). In the frontal plane, the lateral inclination in the lumbar region was made in the opposite direction from the pelvis toward the carrying member. CONCLUSION: Although there is substantial inter-subject variability, our study characterized the angular movements in the three planes of the different spinal junctions, of the pelvis and the lower limbs during a gait cycle in a healthy population.

Curve location influences spinal balance in coronal and sagittal planes but not transversal trunk motion in adolescents with idiopathic scoliosis: a prospective observational study.

PURPOSE: In adolescent idiopathic scoliosis (AIS), spinal deformity can be seen in the thoracic or in the lumbar area. Although differences according to curve location are well described on standard radiographs, dynamic consequences of such difference remain unclear. Our objective was to explore the differences in dynamic spinal balance according to curve location in AIS patients using gait analysis METHODS: We prospectively included 22 females with AIS planned for surgical correction (16.3 years old, 81% Risser ≥ 4). Patients were divided into two matched cohorts, according to major curve location [right thoracic (Lenke 1) or left lumbar (Lenke 5)]. Gait analysis was performed the day before surgery. Global balance was analyzed as the primary outcome. Local curves parameters (dynamic Cobb angles) were defined as the secondary outcome. RESULTS: In coronal plane, Lenke 5 patients had a left trunk shift, whereas trunk was shifted to the right in Lenke 1 patients (- 20.7 vs 6.3, p = 0.001). In the sagittal plane, the main difference between the two groups was T12 position that remained over the pelvis during gait in Lenke 5 patients, whereas it was anterior to the pelvis in Lenke 1 patients. In the transversal plane, Lenke 5 and Lenke 1 patients presented the same gait abnormalities, with a global trunk rotation to the left (- 4.8 vs - 7.6, p = 0,165). CONCLUSION: This is the first study to provide the results of a direct comparison between Lenke 1 and Lenke 5 patients during gait. Curve location influenced coronal and sagittal balance, but abnormalities of transversal trunk motion were the same, wherever the curve was located. These slides can be retrieved under Electronic Supplementary Material.

Characterization of trunk motion in adolescents with right thoracic idiopathic scoliosis.

BACKGROUND: Although standard radiography is currently used for deformity assessment in AIS patients, it is performed in a constrained position and probably not reflective of spinal balance during daily-life activities. Our main objective was to compare trunk motion in Lenke 1 and 2 AIS patients to healthy volunteers, using gait analysis. MATERIAL AND METHODS: Lenke 1 or 2 AIS patients planned for surgery were included. The day before surgery, they underwent radiographic evaluation and gait analysis. Among the gait parameters, sagittal vertical axis (Dyn-SVA), shoulder line rotation (Dyn-SL rotation), pelvis rotation (Dyn-P rotation) and acromion pelvis angle (Dyn-APA) were measured. AIS patients were compared to 25 asymptomatic controls. RESULTS: A total of 57 patients were included in the study, with a mean Cobb angle of 55.4°. AIS patients had a lower Dyn-SVA when compared to controls (47.0 vs. 62.9 mm, p = 0.012). Dyn-APA and Dyn-SL rotation were negative in AIS patients, meaning that shoulder line was rotated towards the left (- 6.4 vs. 7.8° and - 7.5 vs. - 0.4°, p<0.001, respectively). On the other hand, Dyn-P rotation was positive, meaning that pelvis was rotated towards the right side during gait (1.1 vs. - 0.5, p = 0.026). DISCUSSION: This is one of the largest series of gait analysis in AIS patients. We demonstrated that AIS patients have an abnormal gait pattern, with a decreased anterior tilt of the trunk and transverse plane abnormalities. We found that gait deviation was not related to radiographic measurements, pointing out that dynamic assessment provides new data about spinal posture. These slides can be retrieved under Electronic Supplementary Material.

Mortality, complication, and fusion rates of patients with odontoid fracture: the impact of age and comorbidities in 204 cases.

PURPOSE: The French Society of Spine Surgery (SFCR) conducted a prospective epidemiologic multicenter study. The purpose was to investigate mortality, complication, and fusion rates in patients with odontoid fracture, depending on age, comorbidities, fracture type, and treatment. METHODS: Out of 204 patients, 60 were ≤ 70 years and 144 were > 70 years. Demographic data, comorbidities, treatment types and complications (general medical, infectious, neurologic, and mechanical), and death were registered within the first year. Fractures were classified according to Anderson-D'Alonzo and Roy-Camille on the initial CT. A 1-year follow-up CT was available in 144 patients to evaluate fracture consolidation. RESULTS: Type II and oblique-posterior fractures were the most frequent patterns. The treatment was conservative in 52.5% and surgical in 47.5%. The mortality rate in patients ≤ 70 was 3.3% and 16.7% in patients > 70 years (p = 0.0002). Fracture pattern and treatment type did not influence mortality. General medical complications were significantly more frequent > 70 years (p = 0.021) and after surgical treatment (p = 0.028). Neurologic complications occurred in 0.5%, postoperative infections in 2.0%, and implant-related mechanical complications in 10.3% (associated with pseudarthrosis). Fracture fusion was observed in 93.5% of patients ≤ 70 years and in 62.5% >70 years (p < 0.0001). Pseudarthrosis was present in 31.5% of oblique-posterior fractures and in 24.3% after conservative treatment. CONCLUSIONS: Age and comorbidities influenced mortality and medical complication rates most regardless of fracture type and treatment choice. Pseudarthrosis represented the main complication, which increased with age. Pseudarthrosis was most frequent in type II and oblique-posterior fractures after conservative treatment.

Robot-assisted multi-level anterior lumbar interbody fusion: an anatomical study.

BACKGROUND: Minimally invasive surgical approaches still provide limited exposure. Access to the L2-L5 intervertebral discs during a single procedure is challenging and often requires repositioning of the patient and adopting an alternative approach. OBJECTIVES: Investigate the windows to the L2-L5 intervertebral discs to assess the dimensions of the interbody implants suitable for the procedure and evaluate the feasibility of multi-level lumbar intervertebral disc surgery in robot-assisted surgery (RAS) METHODS: Sixteen fresh-frozen cadaveric specimens underwent a retroperitoneal approach to access the L2-L5 intervertebral discs. The L2-L3 to L4-L5 windows were defined as the distance between the left lateral border of the aorta (or nearest common iliac vessel) and the medial border of the psoas, measured in a static state and after gentle medial retraction of the vascular structures. Two living porcine specimens and one cadaveric specimen underwent da Vinci robot-assisted transperitoneal approach to expose the L2-L3 to L4-L5 intervertebral discs and perform multi-level discectomy and interbody implant placement. RESULTS: The L2-L3 to L4-L5 intervertebral disc windows significantly increased from a static to a retracted state (p < 0.05). The mean L2-L3, L3-L4, and L4-L5 windows measured respectively 20.1, 21.6, and 19.6 mm in the static state, and 27.2, 30.9, and 30.3 mm after gentle vascular retraction. The intervertebral windows from L2-L3 to L4-L5 were successfully exposed through an anterior transperitoneal approach with the da Vinci robot on the cadaveric and living porcine specimens, and interbody implants were inserted. CONCLUSION: RAS appears to be feasible for a mini-invasive multi-level lumbar intervertebral disc surgery. The RAS procedure, longer and more expensive than conventional MIS approaches, should be reserved for elective patients.

Experience and volume are determinantive factors for operative management of supracondylar humeral fractures in children.

BACKGROUND: We compared radiographic and operative results of pediatric patients undergoing surgical treatment of displaced supracondylar humeral fracture (SCHF) according to the surgeon's experience. METHODS: During an 11-year period (2006-2016), we reviewed the medical records of 236 patients operated on for Gartland III SCHF in our institution. Operative (operative time, time to implants removal) and radiographic parameters (Baumann and lateral capitellohumeral angles) were assessed. A malalignment was defined if there was a difference in the Baumann angle or lateral capitellohumeral angles >15° or if malrotation existed compared with normative values. We compared surgeon experience and volume (number of patients operated on by year). RESULTS: In patients operated on by less experienced surgeons (<1 year, n = 69), operative time (61 vs. 41 minutes) and time to implant removal (48 vs. 40 days) were significantly longer (P < .001). Radiographic parameters did not differ between less and more experienced surgeons. Operative parameters improved through the 20 first cases of the younger surgeons. In surgeons managing fewer than 5 patients per year, malalignment and conversion to open reduction were more frequent (all P < .05). CONCLUSION: Experience and volume are 2 crucial parameters influencing the quality of management of pediatric patients undergoing surgical treatment for displaced SCHF. They should be taken into account in daily practice, especially when making the decision to operate on these patients out of day time.

Bone substitutes in adolescent idiopathic scoliosis surgery using sublaminar bands: is it useful? A case-control study.

INTRODUCTION: In order to avoid pseudarthrosis in adolescent idiopathic (AIS) patients, it is recommended to bring additional bone graft or substitute. Modern rigid instrumentations have been shown to provide less pseudarthroses even without bone substitutes. The aim of our study was to determine the impact of using bones substitutes on fusion rates in adolescent idiopathic scoliosis patients undergoing PSF with sublaminar bands. METHOD: AIS patients scheduled to undergo PSF with sublaminar bands were prospectively enrolled into this study and not given any bone substitutes (no-substitute group). Data were collected and analyzed in patients with at least two years of follow-up. Pseudarthrosis was diagnosed if at least one of the following was present: persistent back pain, hardware failure, loss of correction greater than 10°. The results were compared to a control group who received bone substitutes for the same surgical procedure. RESULTS: Eighty-eight patients were included. For the whole cohort, the mean age was 14.8 years old and the mean follow-up was 30.9 months. For the 'no-substitute' group (n = 44), the mean Cobb angle was 56° pre-operatively, 20.1° post-operatively, and 22° at final follow-up. The fusion rate was not statistically different between the two groups (97.7% vs 95.5%, p = 0.56). At last follow-up, one pseudarthrosis occurred in the 'no substitute' group and two in the control group. DISCUSSION: This is the first study to determine the impact of bone substitutes in AIS fusion using sublaminar bands. In our study, the use of local autologous bone graft alone resulted in a fusion rate of 97.7% despite the use of more flexible instrumentation. The high rate of fusion in AIS patients is more probably due to the healing potential of these young patients rather than to the type of instrumentation. CONCLUSION: The use of additional bone graft or bone substitutes may not be mandatory when managing AIS. LEVEL OF EVIDENCE: 4.

[Not Available].

Chronic low back pain is extremelyfrequent and its management is still con troversial among spine physicians. For decades, intervertebral fusion has been considered as the gold- standard. However, non fusion techniques have been developed in order to avoid fusion's complications. Numerous studies have reported satisfactory results of total disc arthro- plasty in the management of lumbar degenerative disc disease. So far it is still dificult to prove the superiority of disc replacement over fusion due to a lack of high level studies. The aim of this work was to try to answers various questions related to that technique which was described twenty years ago.

Use of the Universal Clamp in adolescent idiopathic scoliosis.

UNLABELLED: The Universal Clamp (UC) equipped with a soft sublaminar band is a relatively new thoracic anchor that can be used in hybrid constructs. A dedicated reduction tool that applies traction to the sublaminar band permits gentle translation of the thoracic curve to the pre-contoured fusion rods, which have been previously anchored distally by pedicle screws and proximally by hooks in a claw configuration. METHODS: A literature review concerning the use of UC in adolescent idiopathic Scoliosis was performed. RESULTS: The results confirm the efficacy with the UC hybrid constructs, the good correction (71-66%) of the main thoracic curve and low loss of correction at 2-year follow-up (3-4%). The thoracic curve correction achieved and maintained in the AIS patients appears to be substantially higher than that reported for all hook and hook hybrid techniques. Regardless of the deformity correcting method employed with all-screw constructs, the Cobb angle correction achieved is equivalent to that achieved with UC hybrid devices. Among the present AIS patients who had normal values of thoracic kyphosis pre-operatively, there was almost no change in average thoracic kyphosis at the latest follow-up. However, among the patients with low pre-operative values of T5-T12 kyphosis, the average T5-T12 kyphosis improved. CONCLUSION: Hybrid construct with UC is safe, with reduced operative time and blood loss. While achieving deformity correction in the coronal and axial planes equivalent to the best-reported results of all screw or previous hybrid constructs, the UC hybrid technique appears to provide superior correction in the sagittal plane. The excellent outcome is maintained at the 2-year follow-up.

Circumferential fusion using a custom-made screw in the management of high-grade spondylolisthesis.

PURPOSE: Management of high-grade spondylolisthesis is challenging and to date no therapeutic consensus is available. Various surgical procedures have been described using unique or double approach. The aim of the study is to describe an original technique using a posterior-only approach to achieve a circumferential lumbosacral fusion with a custom-made screw. METHODS: In our experience, eight patients (mean age 15 years old) were treated for grade III or IV slipping without instrumental reduction. Surgical technique included a laminectomy from L5 to S2, then after mobilization of neural elements a guide wire was inserted from the posterior side of S2 to the antero-superior corner of L5. A specific drill was used and the 10-mm screw was then inserted under fluoroscopic guidance. Further steps included a discectomy, lumbosacral interbody graft and posterolateral graft to obtain a circumferential fusion. Clinical and radiological evaluations were obtained. RESULTS: On the whole series, solid fusion was achieved after 6 months on average. Sagittal realignment was observed with a regression of pelvic retroversion and hip flessum, a lumbarization of the lumbar lordosis and an improvement of the thoracic kyphosis. For one patient, a postoperative S1 deficit was observed. CONCLUSION: This technique provides satisfactory results in the management of high-grade spondylolisthesis. This concept is based on a double spine instability considering viscoelastic properties of the disc and postoperative sagittal reciprocal changes as prerequisite. This posterior-only approach represents a valuable alternative to other procedures.

Circumferential management of unstable thoracolumbar fractures using an anterior expandable cage, as an alternative to an iliac crest graft, combined with a posterior screw fixation: results of a series of 85 patients.

OBJECT: The optimal management of unstable thoracolumbar fractures remains unclear. The objective of the present study was to evaluate the results of using an expandable prosthetic vertebral body cage (EPVBC) in the management of unstable thoracolumbar fractures. METHODS: Eighty-five patients with unstable T7-L4 thoracolumbar fractures underwent implantation of an EPVBC via an anterior approach combined with posterior fixation. Long-term functional outcomes, including visual analog scale and Oswestry disability index scores, were evaluated. RESULTS: In a mean follow-up period of 16 months, anterior fixation led to a significant increase in vertebral body height, with an average gain of 19%. However, the vertebral regional kyphosis angle was not significantly increased by anterior fixation alone. No significant difference was found between early postoperative, 3-month, and 1-year postoperative regional kyphosis angle and vertebral body height. Postoperative impaction of the prosthetic cage in adjacent endplates was observed in 35% of the cases, without worsening at last follow-up. Complete fusion was observed at 1 year postoperatively and no cases of infections or revisions were observed in relation to the anterior approach. CONCLUSIONS: The use of EPVBCs for unstable thoracolumbar fractures is safe and effective in providing long-term vertebral body height restoration and kyphosis correction, with a moderate surgical and sepsis risk. Anterior cage implantation is an alternative to iliac bone graft fusion and is a viable option in association with a posterior approach, in a single operation without additional risks.

An updated classification of the anatomical variations of the internal iliac venous drainage system: Surgical implications for anterior lumbar spinal approaches.

BACKGROUND: Advanced pelvic surgery is associated with potential vascular risks. The aim of this study was to complete the existing classification of the anatomical variations of the internal iliac veins encountered on a series of preoperative angio CT with a view to performing anterior lumbar spine surgery. MATERIALS AND METHODS: In this monocentric retrospective study conducted between 2010 and 2020, all preoperative angio CT performed before an anterior lumbar surgery were systematically analyzed. All the abnormalities of the iliac veins were referenced in an updated classification system. RESULTS: 910 patients (431 men and 479 women) with a mean age of 49 years [16-88] were included. Apart from the most common variant in the population (type I), 64 anatomical variations (7.0%) in the iliac veins were reported and classified according to our new classification. The percentage of coverage of the L4-L5 intervertebral disc is 52%, including 32% by the inferior vena cava before the confluence of the common iliac veins. At the level of the L5-S1 intervertebral disc, the coverage is 30% (same distribution between left and right). CONCLUSIONS: Variations of the iliac veins are frequent, and contrary to what one might think, and even if they can represent an anatomical trap during surgery, certain variations do not limit anterior lumbar spine surgery and are not more associated with vascular complications. Nevertheless, these anatomical variations must be known before any advanced pelvic surgery. Depending on their distribution, level L5-S1 is more suitable for ALIF, level L4-L5 for OLIF approaches.

Contribution of dynamic cervical MRI to surgical planning for degenerative cervical myelopathy: Revision rate and clinical outcomes at 5 years' postoperative.

INTRODUCTION: Cervical MRI is the gold standard for surgical planning of degenerative cervical myelopathy; however, the symptomatic postoperative recurrence rate is high in the medium and long terms (9.1% to 10.7%) and may bring into question the quality of the preoperative surgical plan. The objective of this study was to evaluate cervical spinal stenosis and intramedullary hyperintensity with dynamic cervical MRI to determine the recurrence rate and clinical improvement in a cohort of patients who had dynamic cervical MRI incorporated into their surgical plan. METHODS: This was a prospective, single-center study. Upon enrolment and at each follow-up visit, patients completed the mJOA score, NDI, cervical pain on visual analog scale (VAS) and radicular pain on VAS. Every enrolled patient underwent dynamic cervical MRI (in neutral, flexion and extension positions). Five levels were measured in the three positions, resulting in 915 levels for analysis. RESULTS: Sixty-one patients were included. Eighty-four levels had an intramedullary hyperintensity in neutral position, 93 in extension and 112 in flexion. The mean sagittal diameter varied the most at C4-C5, going from 7.13mm (SD 2.32) on average in neutral to 6.30mm (SD 2.22) in extension and 8.29mm (SD 2.10) in flexion, a variation of -12% and +16%, respectively. A Mühle grade≥2 was found in 134 levels in neutral position versus 189 in extension and 110 in flexion. None of the patients had worse neurological symptoms following the dynamic cervical MRI. The mean postoperative follow-up was 4.4 years (SD 0.88). Two patients (3.1%) required surgical revision because the implants had shifted. One patient developed symptomatic adjacent segment disease. CONCLUSION: Preoperative surgical planning that incorporates dynamic cervical MRI before the surgical treatment of degenerative cervical myelopathy appears to be a safe and reliable method and one that helps reduce symptoms in the long term. LEVEL OF EVIDENCE: IV.

Thoracolumbar vertebral fracture in unoperated idiopathic scoliosis.

INTRODUCTION: Traumatic fractures of the thoracolumbar spine are common. Their management considers the fracture type according to the various classifications in existence, as well as the patient's background and age. In some cases, the occurrence of a fracture on a spine with an unoperated scoliotic deformity can be observed. This entity, not described in the literature, can pose a therapeutic challenge and is not present in any existing treatment algorithm. The main objective of this work was to describe the characteristics and management of vertebral fractures in patients with unoperated idiopathic scoliosis. MATERIAL AND METHODS: We carried out a monocentric retrospective study in all patients operated on for a spinal fracture between May 2011 and August 2020, with a history of unoperated adolescent idiopathic scoliosis. We collected epidemiological data including the surgical course of each patient and the final result. The patients were categorized according to the surgical strategy (extensive fusion and correction of the deformity, short osteosynthesis without considering the scoliosis, vertebroplasty and orthopedic treatment) and the final clinical and radiological result evaluated at the last follow-up. RESULTS: Ten patients were included in this study with a total number of 16 fractured vertebrae. The population was 80% female, with an average age of 36.3 years. The majority of fractures were type A, at the thoracolumbar junction. The curves were classified as Lenke 1A in 5 cases, 1B in 2 cases, 1C in 1 case and 5C for 2 patients. Ultimately, 3 patients underwent extended fusion with correction of scoliosis, 6 localized osteosynthesis and 1 percutaneous vertebroplasty. In 50% of cases, a change of surgical strategy had to be made, due to worsening of the deformity or hyperalgesia. The last follow-up was at 19.7 months on average. Five patients had a good final clinical result, 5 patients had persistence of significant pain (lower back pain or cruralgia). CONCLUSION: This is the first study investigating the association of vertebral fractures and the presence of unoperated idiopathic scoliosis. The results of our study highlight the management challenges and difficulties in therapeutic decision-making. The presence of a pre-existing curve is thus an important parameter to consider and should lead to the discussion of performing an extended fusion secondarily in view of the risk of poor results from localized surgery. LEVEL OF EVIDENCE: IV.

Spinal Sagittal Alignment Changes During Childhood: Results of a National Cohort Analysis of 1,059 Healthy Children.

BACKGROUND: In the past decades, it has been recognized that sagittal alignment of the spine is crucial. Although the evolution of spinal alignment with growth has previously been described, there are no data for key parameters such as the exact shapes (extent and magnitude) of spinal curvatures. The goals of this study were therefore to determine normative values of spinopelvic sagittal parameters and to explore their variation during growth, based on the analysis of a large national cohort of healthy children. METHODS: The radiographic data of 1,059 healthy children were analyzed in a retrospective, multicenter study. Full spine radiographs were used to measure several sagittal parameters, such as pelvic parameters, T1-T12 thoracic kyphosis (TK), and L1-S1 lumbar lordosis (LL). TK was divided into proximal, middle, and distal parts, and LL was divided into proximal and distal parts. Patients were stratified into 5 groups according to skeletal maturity (based on age, Risser stage, and triradiate cartilage status). RESULTS: During growth, pelvic incidence increased from 40° to 46° and pelvic tilt increased from 4° to 9° (p < 0.05), whereas sacral slope remained constant. The peak of change in pelvic parameters occurred at the beginning of pubertal growth in Group 2 (the first part of the pubertal growth spurt). TK slightly increased among groups from 39° to 41° (p = 0.005), with the peak of change occurring in Group 4 (pubertal growth deceleration). LL increased from 51° to 56° (p < 0.001), with the peak of change occurring in Group 3 (the second part of the pubertal growth spurt). Segmental analysis revealed that most of the TK and LL changes occurred in the distal TK and proximal LL, with the other parts remaining constant. CONCLUSIONS: This is one of the largest studies showing changes in sagittal alignment with growth in normal children and adolescents. We found that changes in spinal shape were cascading phenomena. At the beginning of the growth peak, pelvic incidence increased. This change in pelvic morphology led to an increase in LL, involving its proximal part. Finally, TK increased, in its distal part, at the end of pubertal growth. LEVEL OF EVIDENCE: Prognostic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Thoracolumbar Sagittal Shape Varies With Pelvic Morphology and Aging.

STUDY DESIGN: Retrospective study of a multicenter prospective database. OBJECTIVE: The objective of this study was to determine the organization and correlations between different spinal segments according to pelvic incidence (PI) and age. SUMMARY OF BACKGROUND DATA: When planning surgery for the correction of adult spinal deformities, considering lumbar lordosis (LL) as a uniform segment is an approximation that can lead to planning errors. MATERIALS AND METHODS: Radiographs of 1540 subjects were analyzed and divided into three PI groups: low <45, intermediate 45 to 60, high >60, and stratified by age (<45, 45-70, and >70 yr). The different segments of L1-L4 proximal lumbar lordosis (PLL), L4-S1 distal lumbar lordosis (DLL), and T10-L1 thoracolumbar junction (TLJ) were analyzed. RESULTS: The mean age was 53.5 years (SD=17, minimum=20, maximum=93). There was a significant correlation between thoracic kyphosis T5-T12 and TLJ segment T10-L1 ( r =0.581, P <0.001). Only the L1-L4 PLL segment correlated with PI ( r =0.47, P <0.001). The T10-L1 TLJ segment was constant regardless of age or PI groups considered (mean=-8, SD=9). PLL did not vary with aging but differed according to PI. The DLL showed significant differences between age and PI groups but without a significant correlation between PI and DLL. CONCLUSIONS: Pelvic morphology is known to determine the curvatures of the spine, however, the distribution of LL is not homogeneous. Our study provided a normative value reference and showed that T10-L1 is constant regardless of age or PI. LEVEL OF EVIDENCE: III.