Reassessing the association: Evaluation of a polyalanine deletion variant of RUNX2 in non-syndromic sagittal and metopic craniosynostosis.

The RUNT-related transcription factor RUNX2 plays a critical role in osteoblast differentiation, and alterations to gene dosage cause distinct craniofacial anomalies. Uniquely amongst the RUNT-related family, vertebrate RUNX2 encodes a polyglutamine/polyalanine repeat (Gln23-Glu-Ala17 in humans), with the length of the polyalanine component completely conserved in great apes. Surprisingly, a frequent 6-amino acid deletion polymorphism, p.(Ala84_Ala89)del, occurs in humans (termed 11A allele), and a previous association study (Cuellar et al. Bone 137:115395;2020) reported that the 11A variant was significantly more frequent in non-syndromic sagittal craniosynostosis (nsSag; allele frequency [AF] = 0.156; 95% confidence interval [CI] 0.126-0.189) compared to non-syndromic metopic craniosynostosis (nsMet; AF = 0.068; 95% CI 0.045-0.098). However, the gnomAD v.2.1.1 control population used by Cuellar et al. did not display Hardy-Weinberg equilibrium, hampering interpretation. To re-examine this association, we genotyped the RUNX2 11A polymorphism in 225 individuals with sporadic nsSag as parent-child trios and 164 singletons with sporadic nsMet, restricting our analysis to individuals of European ancestry. We compared observed allele frequencies to the non-transmitted alleles in the parent-child trios, and to the genome sequencing data from gnomAD v.4, which display Hardy-Weinberg equilibrium. Observed AFs (and 95% CI) were 0.076 (0.053-0.104) in nsSag and 0.082 (0.055-0.118) in nsMet, compared with 0.062 (0.042-0.089) in non-transmitted parental alleles and 0.065 (0.063-0.067) in gnomAD v.4.0.0 non-Finnish European control genomes. In summary, we observed a non-significant excess, compared to gnomAD data, of 11A alleles in both nsSag (relative risk 1.18, 95% CI 0.83-1.67) and nsMet (relative risk 1.29, 95% CI 0.87-1.92), but we did not replicate the much higher excess of RUNX2 11A alleles in nsSag previously reported (p = 0.0001).

The influence of lumbosacral transitional vertebrae on lumbar lordosis and the angle of pelvic incidence.

Pelvic incidence and lumbar lordosis have only normative values for spines comprising five lumbar and five sacral vertebrae. However, it is unclear how pelvic incidence and lumbar lordosis are affected by the common segmentation anomalies at the lumbo-sacral border leading to lumbosacral transitional vertebrae, including lumbarisations and sacralisations. In lumbosacral transitional vertebrae it is not trivial to identify the correct vertebral endplates to measure pelvic incidence and lumbar lordosis because ontogenetically the first sacral vertebra represents the first non-mobile sacral segment in lumbarisations, but the second segment in sacralisations. We therefore assessed pelvic incidence and lumbar lordosis with respect to both of these vertebral endplates. The type of segmentation anomaly was differentiated using spinal counts, spatial relationship with the iliac crest and morphological features. We found significant differences in pelvic incidence and lumbar lordosis between lumbarisations, sacralisations and the control group. The pelvic incidence in the sacralised group was mostly below the range of the lubarisation group and the control group when measured the traditional way at the first non-mobile segment (30.2°). However, the ranges of the sacralisation and lubarisation groups were completely encompassed by the control group when measured at the ontogenetically true first sacral vertebra. The mean pelvic incidence of the sacraliation group thus increased from 30.2° to 58.6°, and the mean pelvic incidence of the total sample increased from 45.6° to 51.2°, making it statistically indistinguishable from the control sample, whose pelvic incidence was 50.2°. Our results demonstrate that it is crucial to differentiate sacralisations from lumbarisation in order to assess the reference vertebra for pelvic incidence measurement. Due to their significant impact on spino-pelvic parameters, lumbosacral transitional vertebrae should be evaluated separately when examining pelvic incidence and lumbar lordosis.

Changes in spinal sagittal balance after a new osteoporotic vertebral compression fracture.

We conduct a longitudinal study to examine how new VCF alter spinal sagittal balance. New VCF increased SVA by an average of 2.8 cm. Sagittal balance deteriorates as a VCF develops in the lower lumbar spine. A new fracture below L1 increased the relative risk of a deterioration of sagittal balance 2.9-fold compared to one above Th12. PURPOSE: Studies on the relationship between osteoporotic vertebral fractures and spinal sagittal balance have all been limited to cross-sectional studies. The aim of this study is to conduct a longitudinal study to examine how new vertebral compression fracture (VCF) alter spinal sagittal balance. METHODS: Subjects were patients undergoing periodic examinations after treatment of a vertebral fracture or lumbar spinal canal stenosis. Forty patients who developed a new VCF were included in this study. Full-spine standing radiographs were compared before and after the fracture to examine changes in spinopelvic parameters and factors determining the changes in sagittal balance. RESULTS: The mean age of the patients was 79.0 years. The mean interval between pre- and post-fracture radiographs was 22.7 months, and the mean time between development of a fracture and post-fracture radiographs was 4.6 months. After a fracture, sagittal vertical axis (SVA) increased an average of 2.78 cm and spino-sacral angle (SSA) decreased an average of 5.3°. Both ⊿SVA and ⊿SSA were not related to pre-fracture parameters. The wedge angle of the fractured vertebra was not related to changes in sagittal balance. ⊿SVA increased markedly in patients with a fracture of the lower lumbar vertebrae. receiver operating characteristic analysis revealed that the relative risk of a deterioration of sagittal balance was 2.9 times higher for a new fracture below L1 than for a fracture above Th12. CONCLUSION: New VCF increased SVA by an average of 2.8 cm. Sagittal balance deteriorates as a new fracture develops in the lower lumbar spine. Early intervention in osteoporosis is vital for the elderly.

Osteoporotic vertebral fractures localized in the lumbar area significantly impact sagittal alignment.

Lumbar fractures and/or multiple fractures at the lumbar or thoracolumbar regions are risk factors for sagittal malalignment in patients older than 70 years old. Although patients with OVF show a huge capacity to compensate after the fractures, lumbar and TL lumbar fractures require closer monitoring. PURPOSE: To assess the impact of osteoporotic vertebral fractures on the sagittal alignment of the elderly and identify risk factors for sagittal malalignment. METHODS: We performed a retrospective study on a cohort of 249 patients older than 70 years old and diagnosed with osteoporosis who suffered chronic vertebral fractures. Demographic and radiological data were collected. Full-spine lateral X-rays were obtained to analyze the sagittal plane. Patients were classified according to the number and location of the fractures. Pearson's correlation coefficient was used to assess the relationships between the type of fractures and sagittal alignment. RESULTS: A total of 673 chronic fractures were detected in 249 patients with a mean number of vertebral fractures per patient of 2.7 ± 1.9. Patients were divided into 9 subgroups according to the location and the number of fractures. Surprisingly, any of the aggregated parameters used to assess sagittal alignment exceeded the threshold defined for malalignment. In the second part of the analysis, 41 patients with sagittal malalignment were identified. In this subpopulation, an overrepresentation of patients with lumbar fractures (34% vs. 11%) and an under-representation of thoracic fractures (9% vs. 34%) were reported. We also observed that patients with 3 or more lumbar or thoracolumbar fractures had an increased risk of sagittal malalignment. CONCLUSIONS: Lumbar fractures and/or multiple fractures at the lumbar or thoracolumbar regions are risk factors for sagittal malalignment in patients older than 70 years old. Although patients show a remarkable capacity to compensate, fractures at the lumbar and thoracolumbar regions need closer monitoring.

Cerebral Sinus Hemodynamics in Adults Revealed by 4D Flow MRI.

BACKGROUND: The hemodynamics of the cerebral sinuses play a vital role in understanding blood flow-related diseases, yet the hemodynamics of the cerebral sinuses in normal adults remains an unresolved issue. PURPOSE: To evaluate hemodynamics in the cerebral sinus of adults using 4-dimensional flow MRI (4D Flow MRI). STUDY TYPE: Cross-sectional. POPULATION: Ninety-nine healthy volunteers (mean age, 42.88 ± 13.16 years old; females/males, 55/44). FIELD STRENGTH/SEQUENCE: 3 T/4D Flow MRI. ASSESSMENT: The blood flow velocity, average blood flow rate (Q), and vortexes at the superior sagittal sinus (SSS), straight sinus (STS), transverse sinus, sigmoid sinus, and jugular bulb of each volunteer were evaluated by two independent neuroradiologists. The relationship between the total cerebral Q and sex and age was also assessed. Twelve volunteers underwent two scans within a month. STATISTICAL TESTS: The intraclass correlation coefficient (ICC) evaluated the inter-observer agreement. Blood flow parameters among volunteers were compared by the independent-sample t-test or Mann-Whitney U test. The multiple linear regression equation was used to evaluate the relationship between total cerebral Q and age and sex. P < 0.05 indicated statistical significance. RESULTS: The test-retest and interobserver reliability of average velocity and Q were moderate to high (ICC: 0.54-0.99). Cerebral sinus velocity varied by segment and cardiac cycle. The SSS's velocity and Q increased downstream and Q near torcular herophili was 3.5 times that through the STS. The total cerebral Q decreased by 0.06 mL/s per year (ß = -0.06 ± 0.013) and was sex-independent within the group. Vortexes were found in 12.12%, 8.9%, and 59.8% of torcular herophili, transverse-sigmoid junction, and jugular bulb, respectively, and were related to higher upstream flow. DATA CONCLUSION: Cerebral sinuses could be measured visually and quantitatively in vivo by 4D Flow MRI, providing a basis for future research on pulsating tinnitus, multiple sclerosis, and other related diseases. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 1.

EOS® is reliable to evaluate spinopelvic parameters: a validation study.

BACKGROUND: Sagittal and coronal standing radiographs have been the standard imaging for assessing spinal alignment. However, their disadvantages include distortion at the image edges and low interobserver reliability in some parameters. EOS® is a low-dose biplanar digital radiographic imaging system that can avoid distortion by obtaining high-definition images. METHODS: This study aimed to evaluate spinopelvic parameters in conventional lateral C1S1 upright radiographs and EOS® images and compare them. Patients with non-deformity changes were subjected to routine clinical examinations. Plain AP and lateral X-ray radiographs were obtained along the entire spine length. Patients were also referred for full-length EOS® of the spine. Thoracic Kyphosis (TK), Lumbar Lordosis (LL), Pelvic Tilt (PT), Sacral Slope (SS), Pelvic Incidence (PI), and Sagittal Vertical Axis (SVA) were measured in the two studies by an orthopedic surgeon and a radiologist using PACS software. Also, the orthopedic surgeon evaluated the studies again after two weeks. Intra- and inter-observer reliability was then assessed using the interclass correlation coefficient (ICC). Also, the coefficient of variation was used to assess intra- and inter-observer reliability. Bland-Altman plots were drawn for each parameter. RESULTS: The mean age was 48.2 ± 6.6 years. Among the 50 patients, 30 (60%) were female. The mean ICC for TK, LL, PT, SS, PI, and SVA in EOS® images are 0.95, 0.95, 0.92, 0.90, 0.94, and 0.98, respectively, and in C1S1 radiography images, it was 0.92, 0.87, 0.94, 0.88, 0.93, and 0.98, respectively which shows good to excellent results. The coefficient of variation for intraobserver reliability was relatively low (< 18.6%), while it showed higher percentages in evaluating interobserver reliability (< 54.5%). Also, the Bland-Altman plot showed good agreement for each parameter. CONCLUSION: Spinopelvic parameters, e.g., TK, LL, SS, PI, and SS, in EOS® are reliable and comparable to those in conventional lateral upright C1S1 radiographs.

New sagittal abdominal diameter and transverse abdominal diameter based equations to estimate visceral fat area in type 2 diabetes patients.

OBJECTIVE: Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) are considered gold standards for measuring visceral fat area (VFA). However, their relatively high prices and potential radiation exposure limit their widespread use in clinical practice and everyday life. Therefore, our study aims to develop a VFA estimated equation based on sagittal abdominal diameter (SAD) and transverse abdominal diameter (TAD) using anthropometric indexes. To the best of our knowledge, there have been limited studies investigating this aspect thus far. METHODS: This study was designed as a cross-sectional, retrospective cohort survey. A total of 288 patients (167 males and 121 females) aged 18-80 with type 2 diabetes (T2D) were consecutively collected from a multicenter hospital, and VFA was measured by CT. Subsequently, variables highly correlated with VFA were screened through general linear correlation analysis. A stepwise regression analysis was then conducted to develop a VFA estimated equation. Discrepancies between the estimated and actual VFA values were assessed using the Bland-Altman method to validate the accuracy of the equation. RESULTS: In the female T2D population, triglyceride (TG), SAD, TAD were found to be independently correlated with VFA; in the male T2D population, BMI, TG, SAD and TAD showed independent correlations with VFA. Among these variables, SAD exhibited the strongest correlation with VFA (r = 0.83 for females, r = 0.88 for males), followed by TAD (r = 0.69 for females, r = 0.79 for males). Based on these findings, a VFA estimated equation was developed for the T2D population: VFA (male) =-364.16 + 15.36*SAD + 0.77*TG + 9.41*TAD - 5.00*BMI (R2 = 0.75, adjusted R2 = 0.74); VFA(female)=-170.87 + 9.72*SAD-24.29*(TG^-1) + 3.93*TAD (R2 = 0.69, adjusted R2 = 0.68). Both models demonstrated a good fit. The Bland-Altman plot indicated a strong agreement between the actual VFA values and the estimated values, the mean differences were close to 0, and the majority of differences fell within the 95% confidence interval. CONCLUSIONS: In the T2D population, a VFA estimated equation is developed by incorporating SAD and TAD along with other measurement indices. This equation demonstrates a favorable estimated performance, suggesting to the development of novel and practical VFA estimation models in the future study.

Comparison of emotional and behavioral regulation between metopic and sagittal synostosis.

PURPOSE: Children with surgically corrected nonsyndromic craniosynostosis have been previously found to have neurocognitive and behavioral difficulties. Children with metopic synostosis have been described to have more difficulties than children with sagittal synostosis. This study aims to characterize the behavioral differences between children with metopic and sagittal synostosis. METHODS: Children with metopic and sagittal synostosis were recruited at school age. Parents completed four separated behavioral assessments: Conners-3 (evaluation of ADHD), Social Responsiveness Scale-2 (SRS-2: evaluation of autism), Behavior Rating Inventory of Executive Function-2 (BRIEF-2: evaluation of executive function), and Child Behavior Checklist (CBCL: evaluation of overall behavioral problems). Children underwent intelligence quotient (IQ) testing using the Wechsler Abbreviated Scale of Intelligence (WASI-II). RESULTS: There were 91 children (45 with metopic and 46 with sagittal synostosis). More children with metopic synostosis reported requiring supportive services (57.7% vs 34.7%, p = 0.02) and more reached or exceeded borderline clinical levels of two executive function subscales of the BRIEF-2 (emotion regulation index: 33.3% vs 17.4%, p = 0.05; global executive composite: 33.3% vs 17.4%, p = 0.05). Children with sagittal synostosis had higher scores on the rule-breaking and externalizing problem subscales of the CBCL. Increasing age at surgery was associated with worse executive function scores. CONCLUSIONS: A relationship between suture subtype and behavioral outcomes exists at school age. More children with metopic synostosis required social services indicating more overall difficulties. Children with metopic synostosis have more specific problems with executive function, while children with sagittal synostosis had more difficulties with externalizing behaviors.

Atypical sagittal suture craniosynostosis: pathological considerations for early closure of the anterior part of the sagittal suture.

Sagittal suture synostosis is one of the most common craniosynostoses and is often diagnosed by characteristic narrow and long skull shape, scaphocephaly. However, some patients with sagittal suture synostosis do not present with typical scaphocephaly, making early diagnosis difficult. In this study, five cases of characteristic skull deformity showing a narrowing of the cranium posterior to the coronal suture on computed tomography (CT) are presented. The three older children presented with papilledema and intellectual disability and a closed sagittal suture on CT. The two infant cases were diagnosed with the characteristic cranial deformities with aggravation of the deformity over time, but sagittal suture closure was not evident on CT. All patients underwent cranial remodeling surgery. In the two infant cases, the histopathological findings showed that the anterior part of the sagittal suture was firmly fused with fibrous tissue without bony fusion. These findings suggested that narrowing of the cranium posterior to the coronal suture might be due to functional fusion of the anterior portion of the sagittal suture prior to bony fusion. In an infant presenting with such a deformity that shows aggravation of the deformity over time, surgical treatment should be considered.

Efficacy and safety of sagittal synostosis surgery in older (> 12 months) patients: a systematic review and meta-analysis.

PURPOSE: Sagittal synostosis is the most common isolated craniosynostosis. Surgical treatment of this synostosis has been extensively described in the global literature, with promising outcomes when it is performed in the first 12 months of life. However, in some cases, patients older than 12 months arrive at the craniofacial center with this synostosis. A comprehensive study on efficacy and perioperative outcomes has yet to be fully explored in this population. This systematic review and meta-analysis aimed to assess the available evidence of surgical outcomes for the treatment of sagittal synostosis among older patients to analyze the efficacy and safety of synostosis surgery in this unique population. METHODS: PubMed, Embase, and Scopus were searched for studies published from inception to March 2024 reporting surgical outcomes of synostosis surgery in older patients (> 12 months) with isolated sagittal synostosis. The main outcome was the reoperation rate, with secondary endpoints including transfusion rates, aesthetic outcomes, and surgical complications. RESULTS: Nine studies were included in the final analysis. The pooled proportion of the reoperation rate was 1%. The rate of excellent aesthetic results was 95%. The need for transfusion associated with the procedures was 86%, and finally, surgical complications attained a pooled ratio of 2%, indicating minimal morbidity associated with the surgical repair. CONCLUSION: Sagittal synostosis surgery is a safe and effective procedure to perform in older patients; this meta-analysis suggests that open surgery confers a significant rate of excellent aesthetic results with a low reoperation rate and minimal complications associated with the intervention. Future research with direct comparisons among different techniques will validate the findings of this study, which will all contribute to the rigor of synostosis management.

Long-term results of minimally invasive strip craniectomy without helmet therapy for scaphocephaly - a single-centre experience.

Scaphocephaly is the most common type of craniosynostosis and various surgical techniques are used for treatment. Due to late postoperative changes of the head shape, long-term outcome data is important for evaluating any new surgical technique. At our institution, minimally invasive strip craniectomy without regular helmet therapy is the standard treatment in scaphocephalic patients. Between October 2021 and February 2023, we retrospectively examined the skull shape of patients who underwent minimally invasive strip craniectomy for scaphocephaly using a 3D surface scan technique. The cephalic index (CI), the need for helmet therapy and additional cosmetic outcome parameters were investigated. We included 70 patients (72.5% male). The mean follow-up time was 46 (10-125) months and the mean CI was 75.7 (66.7-85.2). In 58 patients, the final cosmetic result was rated as "excellent/good" (mean CI: 76.3; 70.4-85.0), in 11 as "intermediate" (mean CI: 73.3; 66.7-77.6), and in one case as "unsatisfactory" (CI 69.3). The presence of a suboccipital protrusion was associated with a "less than good" outcome. The CI correlated significantly with the overall outcome, the presence of frontal bossing, and the interval between scan and surgery (age at scan). Minimally invasive strip craniectomy is an elegant and safe method to correct scaphocephaly. Our data show good cosmetic results in the long term even without regular postoperative helmet therapy.

A finite element analysis of stress distribution with various directions of intermaxillary fixation using orthodontic mini-implants and elastics following mandibular advancement with a bilateral sagittal split ramus osteotomy.

OBJECTIVE: This finite element analysis (FEA) aimed to assess the stress distribution in the mandible and fixation system with various directions of the intermaxillary fixation (IMF) using mini-implants (MIs) and elastics following mandibular advancement with a bilateral sagittal split ramus osteotomy (BSSRO). MATERIALS AND METHODS: A total of nine mandibular advancement models were set according to the position of the MIs (1.6 mm in diameter, 8 mm in length) and direction of the IMF elastics (1/4 inch, 5 oz). Major and minor principal stresses in the cortical and cancellous bones, von Mises stresses in the fixation system (miniplate and monocortical screws), and bending angles of the miniplate were analysed. RESULTS: Compressive and tensile stress distributions in the mandible and von Mises stress distributions in the fixation system were greater in models with a Class III IMF elastic direction and a higher IMF elastic force than in models with a Class II IMF elastic direction and a lower IMF elastic force. The bending angle of the miniplate was negligible. CONCLUSIONS: Stress distributions in the bone and fixation system varied depending on the direction, amount of force, and position of IMF elastics and MIs. Conclusively, IMF elastics in the Class II direction with minimal load in the area close to the osteotomy site should be recommended.

C4 constant vertebra: a novel benchmark of physiological cervical sagittal alignment.

BACKGROUND: Cervical sagittal alignment is essential, and there is considerable debate as to what constitutes physiological sagittal alignment. The purpose of this study was to identify constant parameters for characterizing cervical sagittal alignment under physiological conditions. METHODS: A cross-sectional study was conducted in which asymptomatic subjects were recruited to undergo lateral cervical spine radiographs. Each subject was classified according to three authoritative cervical sagittal morphology classifications, followed by the evaluation of variations in radiological parameters across morphotypes. Moreover, the correlations among cervical sagittal parameters, age, and cervicothoracic junction parameters were also investigated. RESULTS: A total of 183 asymptomatic Chinese subjects were enrolled with a mean age of 48.4 years. Subjects with various cervical sagittal morphologies had comparable C4 endplate slope angles under all three different typing systems. Among patients of different ages, C2-C4 endplate slope angles remained constant. Regarding the cervicothoracic junction parameters, T1 slope and thoracic inlet angle affected cervical sagittal parameters, including cervical lordosis and C2-7 sagittal vertical axis, and were correlated with the endplate slope angles of C5 and below and did not affect the endplate slope angles of C4 and above. In general, the slope of the C4 inferior endplate ranges between 13° and 15° under different physiological conditions. CONCLUSIONS: In the asymptomatic population, the C4 vertebral body maintains a constant slope angle under physiological conditions. The novel concept of C4 as a constant vertebra would provide a vital benchmark for diagnosing pathological sagittal alignment abnormalities and planning the surgical reconstruction of cervical lordosis.

Defining threshold for sagittal correction in lumbar fractures.

PURPOSE: Surgical indications for thoraco-lumbar fractures are driven both by neurological status, fractures instability and kyphotic deformity. Regarding kyphotic deformity, an angulation superior to 20° is considered by many surgeons as a surgical indication to reduce the disability induced by post-traumatic kyphosis. However, there is a lack of data reporting the ideal or theoretical lordosis that one must have in a particular lumbar segment on CT-scan. The main goal of this study was to determine the mean value for segmental lumbar lordosis according to pelvic incidence (PI) on a cohort of normal subjects. METHODS: The consecutive CT-scan of 171 normal adult subjects were retrospectively analyzed. The PI and the segmental lordosis (L4S1, L3L5, L2L4, L3L1, L2T12 and T11-L1) were measured on all CT-scan. The mean values were calculated for the global cohort and a sub-group analysis according to IP ranges (< 45°, 45 < IP < 60° and > 60°) was performed. RESULTS: The mean angular values for the whole cohort were IP: 54, 9°; L4S1: - 38, 1°; L3L5: - 30, 6°; L2L4: - 14, 1°; L1L3: - 4, 9°; T12L2: + 1, 9° and T11L1: + 5, 4°. The segmental values vary significatively with PI ranges, as for L3L5: - 26, 8° (PI < 45°); - 30° (45 < PI < 60°) and - 35, 1° (PI > 60°). CONCLUSION: These results provide a referential of theoretical values of segmental lordosis according to PI. This abacus may help spinal surgeon in their decision-making process regarding lumbar fractures, to determine the amount of sagittal correction needed, according to the PI range, to be adapted to the sagittal morphology of the patient. LEVEL OF EVIDENCE: III.

Normal spinopelvic parameters and correlation analysis in 217 asymptomatic children.

BACKGROUND: Understanding spinal sagittal balance is crucial for assessing and treating spinal deformities in pediatric populations. OBJECTIVE: The aim of the present observational study is to examine the parameters of sagittal alignment of the regional spine and spinopelvic region in asymptomatic pediatric populations and the characteristics of these parameters with age and sex. METHODS: We enrolled 217 participants, consisting of 112 males (51.6%) and 105 females (48.4%), aged between 4 and 15 years, with an average age of 12.19 years. Pelvic incidence, pelvic tilt, sacral slope, lumbar lordosis, thoracic kyphosis, T1 slope, C7 slope, cervical sagittal vertical axis, and C2-7 Cobb angle were measured. Three spine surgeons conducted radiographic measurements utilizing the PACS software. The measurement reliability was assessed through ICCs. RESULTS: Our results show significant age-related changes in pelvic tilt and cervical sagittal vertical axis, with notable gender differences in pelvic tilt, lumbar lordosis, and thoracic kyphosis. Girls have larger PT, boys have larger cSVA. PI, PT, and cSVA also differ among different age groups. Correlation analysis shows that a series of relationships that align with adult population patterns between pelvic incidence, pelvic tilt, sacral slope, lumbar lordosis, and thoracic kyphosis. CONCLUSION: Significant variations in PT and cSVA across diverse age cohorts highlights notable disparities in the distribution of PT and cSVA values within the pediatric population. Gender-based differences in PT, LL, and TK and correlation in spinopelvic parameter could enhances our understanding of compensatory mechanisms.

Adult spinal deformity correction surgery using age-adjusted alignment thresholds: clinical outcomes and mechanical complication rates. A systematic review of the literature.

PURPOSE: Adult spinal deformity (ASD) surgery gives good clinical outcomes but has a high rate of mechanical complications (MC). In 2016, Lafage described the age-adjusted alignment thresholds (AAAT) to adapt the correction in relation to patient's age proposing less aggressive corrections for the elderly population. The aim of this review was to clarify the effectiveness of AAAT to achieve good health-related quality of life (HRQoL) and their relationship with post-operative MC. MATERIALS AND METHODS: We performed a review of the literature, including articles reporting data on post-operative HRQoL and MC rates in relation to the AAAT. Data were stratified according to whether they matched the AAAT, dividing the population in undercorrected (U), matched (M) and overcorrected (O). The quality of the included studies was assessed using the GRADE and MINORS systems. RESULTS: Six articles reporting data from 1,825 patients were included. The different categories (U, M and O) had homogeneous pre-operative sagittal parameters (p > 0.05) that became statistically different after surgeries (p < 0.05). Proximal junctional kyphosis (PJK) was more frequent in the O group compared to U (p = 0.05). Post-operative HRQoL parameters were similar in the 3 groups (p > 0.05). The quality of the included studies was generally low with a high bias risk. CONCLUSION: The results extrapolated from this review are interesting, as for the same HRQoL the U group had a lower MC rate. Unfortunately, the results are inconsistent, mainly because of the low quality of the included studies and the lack of reporting of some important patient- and surgery-related factors.

Restoring the ideal Roussouly sagittal alignment in Lenke 5 adolescent idiopathic scoliosis patients: a method for decreasing the risk of proximal junctional kyphosis.

PURPOSE: Although the Roussouly classification has been widely used in surgical planning for adult scoliosis patients, little is known about whether it can be used to guide sagittal correction for adolescent idiopathic scoliosis (AIS) patients. The purpose of this study was to explore whether the Roussouly classification could be used to help surgeons restore the ideal sagittal alignment for AIS patients to avoid the development of proximal junctional kyphosis (PJK). METHODS: In this retrospective cohort study, eighty-seven patients with Lenke 5 AIS who underwent surgery from January 2010 to August 2020 were enrolled and divided into two groups: the PJK group and the non-PJK group. All patients were classified into "current types" and "ideal types" according to two versions of the Roussouly classification, and the mismatch rate was evaluated in terms of the consistency between their current type and ideal type. Student's t test, Mann‒Whitney U test, Pearson's Chi-square test, and others were used to compare the two groups regarding patient demographic characteristics (age, sex, Risser sign, etc.) and radiographic parameters (sagittal vertical axis [SVA]; thoracic kyphosis [TK]; thoracolumbar junctional kyphosis [TLK]; lumbar lordosis [LL]; pelvic incidence [PI]; pelvic tilt [PT]; sacral slope [SS]; upper instrumented vertebra [UIV]; lower instrumented vertebra [LIV]; etc.). Multivariate logistic regression with backwards stepwise selection was performed to identify the risk factors for PJK. RESULTS: PJK was observed in 16 out of 87 patients (18.4%) until the final follow-up. The incidence of PJK was significantly higher in the patients not matching their ideal type than in those who did after surgery (60.9% vs. 3.1%, p = 0.000). The patients with ideal Type 1 had the highest incidence of PJK, while the lowest incidence was observed in patients with ideal Type 2 (50.0% vs. 5.1%, p = 0.000). The PJK group had greater TK, LL, and PI-LL than the non-PJK group before and after surgery. The postoperative PJA in the PJK group was also larger than that in the non-PJK group. Multivariate logistic regression revealed that postoperative Roussouly type mismatch was significantly associated with the occurrence of PJK (OR = 64.2, CI = 9.6-407.1, p = 0.000). CONCLUSIONS: The Roussouly classification could serve as a prognostic tool for PJK in Lenke 5 AIS patients. Corrective surgery should restore sagittal alignment with respect to the patient's ideal sagittal profile (according to the Roussouly classification based on the PI) to decrease the incidence of PJK in AIS patients.

Sagittal alignment of diverse mechanical complications following adult spinal deformity surgery.

PURPOSE: To compare the sagittal alignment of patients with diverse mechanical complications (MCs) following adult spinal deformity (ASD) surgery with that of patients without MCs. METHODS: A total of 371 patients who underwent ASD surgery were enrolled. The sagittal spinopelvic parameters were measured preoperatively and at the 6-month and last follow-up, and the global alignment and proportion (GAP) score was calculated. The subjects were divided into non-MC and MCs groups, and the MCs group was further divided into rod fracture (RF), screw breakage (SB), screw dislodgement (SD) and proximal junctional kyphosis (PJK) subgroups. RESULTS: Preoperatively, the RF group had greater thoracolumbar kyphosis (TLK) and relative upper lumbar lordosis (RULL); the SB group had the largest pelvic incidence (PI) and lumbar lordosis (LL); the SD group had the least global sagittal imbalance; and the PJK group had the highest thoracic kyphosis (TK), TLK and RULL. At the last follow-up, the RF and SB groups featured a large PI minus LL (PI-LL), while the PJK group featured a prominent TK; all the MCs subgroups had sagittal malalignment and a higher GAP score, and the SB group had the most severe cases. Logistic regressions showed that the relative spinopelvic alignment (RSA) score was correlated with RF, SB and SD, while the RSA and age scores were associated with PJK. CONCLUSION: Each patient with MCs had individual characteristics in the sagittal plane following ASD surgery, which may be helpful to understand the pathophysiology of poor sagittal alignment with its subsequent MCs and guide an eventual revision strategy.

Sex-dependent evolution of whole-body postural alignment with age.

PURPOSE: The goal of this study was to explore sex-related variations of global alignment parameters and their distinct evolution patterns across age groups. METHODS: This multicentric retrospective study included healthy volunteers with full-body biplanar radiographs in free-standing position. All radiographic data were collected from 3D reconstructions: global and lower limb parameters, pelvic incidence (PI) and sacral slope (SS). Lumbar lordosis (LL), thoracic kyphosis (TK) and cervical lordosis (CL) were also assessed as well as the lumbar and thoracic apex, and thoracolumbar inflexion point. The population was divided into five 5 age groups: Children, Adolescents, Young, Middle-Aged and Seniors. RESULTS: This study included 861 subjects (53% females) with a mean age of 34 ± 17 years. Mean PI was 49.6 ± 11.1 and mean LL was - 57.1 ± 11.6°. Females demonstrated a PI increase between Young and Middle-Aged groups (49 ± 11° vs. 55 ± 12°, p < 0.001) while it remained stable in males. SS and LL increased with age in females while remaining constant in males between Children and Middle-aged and then significantly decreased for both sexes between Middle-Aged and Seniors. On average, lumbar apex, inflexion point, and thoracic apex were located one vertebra higher in females (p < 0.001). After skeletal maturity, males had greater TK than females (64 ± 11° vs. 60 ± 12°, p = 0.04), with significantly larger CL (-13 ± 10° vs. -8 ± 10°, p = 0.03). All global spinal parameters indicated more anterior alignment in males. CONCLUSION: Males present more anteriorly tilted spine with age mainly explained by a PI increase in females between Young and Middle-Aged, which may be attributed to childbirth. Consequently, SS and LL increased before decreasing at senior age.

Analysis of spinopelvic parameters in adult patients with lumbosacral transitional vertebrae.

PURPOSE: Spinopelvic sagittal alignment is crucial for assessing balance and determining treatment efficacy in patients with adult spinal deformity (ASD). Only a limited number of reports have addressed spinopelvic parameters and lumbosacral transitional vertebrae (LSTV). Our primary objective was to study spinopelvic sagittal parameter changes in patients with LSTV. A secondary objective was to investigate clinical symptoms and quality of life (QOL) in patients with LSTV. METHODS: In this study, we investigated 371 participants who had undergone medical check-ups for the spine. LSTV was evaluated using Castellvi's classification, and patients were divided into LSTV+ (type II-IV, L5 vertebra articulated or fused with the sacrum) and LSTV- groups. After propensity score matching for demographic data, we analyzed spinopelvic parameters, sacroiliac joint degeneration, clinical symptoms, and QOL for these two participant groups. Oswestry Disability Index (ODI) scores and EQ-5D (EuroQol 5 dimensions) indices were compared between the two groups. RESULTS: Forty-four patients each were analyzed in the LSTV + and LSTV- groups. The LSTV + group had significantly greater pelvic incidence (52.1 ± 11.2 vs. 47.8 ± 10.0 degrees, P = 0.031) and shorter pelvic thickness (10.2 ± 0.9 vs. 10.7 ± 0.8 cm, P = 0.018) compared to the LSTV- group. The "Sitting" domain of ODI (1.1 ± 0.9 vs. 0.6 ± 0.7, P = 0.011) and "Pain/Discomfort" domain of EQ-5D (2.0 ± 0.8 vs. 1.6 ± 0.7, P = 0.005) were larger in the LSTV + group. CONCLUSION: There was a robust association between LSTV and pelvic sagittal parameters. Clinical symptoms also differed between the two groups in some domains. Surgeons should be aware of the relationship between LSTV assessment, radiographic parameters and clinical symptoms.