Safety of anterior cervical corpectomy and fusion (ACCF) for the treatment of subaxial cervical spine injuries, a single center comparative matched analysis.

INTRODUCTION: Anterior Cervical Discectomy and Fusion (ACDF) and Anterior Cervical Corpectomy and Fusion (ACCF) are both common surgical procedures in the management of pathologies of the subaxial cervical spine. While recent reviews have demonstrated ACCF to provide better decompression results compared to ACDF, the procedure has been associated with increased surgical risks. Nonetheless, the use of ACCF in a traumatic context has been poorly described. The aim of this study was to assess the safety of ACCF as compared to the more commonly performed ACDF. METHODS: All patients undergoing ACCF or ACDF for subaxial cervical spine injuries spanning over 2 disc-spaces and 3 vertebral-levels, between 2006 and 2018, at the study center, were eligible for inclusion. Patients were matched based on age and preoperative ASIA score. RESULTS: After matching, 60 patients were included in the matched analysis, where 30 underwent ACDF and ACCF, respectively. Vertebral body injury was significantly more common in the ACCF group (p = 0.002), while traumatic disc rupture was more frequent in the ACDF group (p = 0.032). There were no statistically significant differences in the rates of surgical complications, including implant failure, wound infection, dysphagia, CSF leakage between the groups (p ≥ 0.05). The rates of revision surgeries (p > 0.999), mortality (p = 0.222), and long-term ASIA scores (p = 0.081) were also similar. CONCLUSION: Results of both unmatched and matched analyses indicate that ACCF has comparable outcomes and no additional risks compared to ACDF. It is thus a safe approach and should be considered for patients with extensive anterior column injury.

Predictors of early mortality following surgical or nonsurgical treatment of subaxial cervical spine fractures: a retrospective nationwide registry study.

BACKGROUND: Traumatic subaxial cervical spine fractures are a significant public health concern due to their association with spinal cord injuries (SCI). Despite being mostly caused by low-energy trauma, these fractures significantly contribute to morbidity and mortality. Currently, research regarding early mortality based on the choice of treatment following these fractures is limited. Identifying predictors of early mortality may aid in postoperative patient monitoring and improve outcomes. PURPOSE: This study aimed to identify predictors of 30-days, 90-days, and 1-year mortality in adults treated for subaxial fractures. STUDY DESIGN: A retrospective review of the nationwide Swedish Fracture Register (SFR). PATIENT SAMPLE: All adult patients in the SFR who underwent treatment for a subaxial cervical fracture (n = 1,963). OUTCOME MEASURES: Analyzed variables included age, sex, injury mechanism, neurological function, fracture characteristics, and treatment type. The primary endpoints were 30-days, 90-days, and 1-year mortality. METHODS: About 1,963 patients in the SFR, treated for subaxial cervical fractures between 2013 and 2021, were analyzed. Surgical procedures included anterior, posterior, or anteroposterior approaches. Nonsurgical treatment included collar treatment or medical examinations without intervention. Stepwise regression and Cox regression analysis were used to determine predictors. Model performance was tested using the area under the receiver operating characteristic curve (AUC). RESULTS: 620 patients underwent surgery and 1,343 received nonsurgical treatment. Surgical cases had primarily translation fractures, with 323 (52%) displaying no neurological deficits. Mortality rates at 30 days, 90 days, and 1 year were 22/620 (3.5%), 35/620 (5.6%), and 53/620 (8.5%), respectively. Age and SCI were predictors of mortality. Nonsurgically treated patients mostly had compression fracture, with 1,214 (90%) experiencing no neurological deficits. Mortality rates at 30 days, 90 days, and 1 year were 41/1,343 (3.1%), 71/1,343 (5.3%), and 118/1,343 (8.7%). Age, male sex, SCI and fractures occurring at the C3 or C6 levels were predictors of mortality. An intact neurological function was a positive predictor of survival among nonsurgically treated patients (AUC >0.78). CONCLUSIONS: Age and SCI emerged as significant predictors of early mortality in both surgically and nonsurgically treated patients. An intact neurological function served as a protective factor against early mortality in nonsurgically treated patients. Fractures at C3 or C6 vertebrae may impact mortality.

Patient-reported outcomes after minimally invasive sacro-iliac joint surgery: a cohort study based on the Swedish Spine Registry.

BACKGROUND AND PURPOSE: There is conflicting evidence regarding treatment outcomes after minimally invasive sacroiliac joint fusion for long-lasting severe sacroiliac joint pain. The primary aim of our cohort study was to investigate change in patient-reported outcome measures (PROMs) after minimally invasive sacroiliac joint surgery in daily practice in the Swedish Spine Registry. Secondary aims were to explore the proportion of patients reaching a patient acceptable symptom score (PASS) and the minimal clinically important difference (MCID) for pain scores, physical function, and health-related quality of life outcomes; furthermore, to evaluate self-reported satisfaction, walking distance, and changes in proportions of patients on full sick leave/disability leave and report complications and reoperations. METHODS: Data from the Swedish Spine Registry was collected for patients with first-time sacroiliac joint fusion, aged 21 to 70 years, with PROMs available preoperatively, at 1 or 2 years after last surgery. PROMs included Oswestry Disability Index (ODI), Numeric Rating Scale (NRS) for low back pain (LBP) and leg pain, and EQ-VAS, in addition to demographic variables. We calculated mean change from pre- to postoperative and the proportion of patients achieving MCID and PASS. RESULTS: 68 patients had available pre- and postoperative data, with a mean age of 45 years (range 25-70) and 59 (87%) were female. At follow-up the mean reduction was 2.3 NRS points (95% confidence interval [CI] 1.6-2.9; P < 0.001) for LBP and 14.8 points (CI 10.6-18.9; P < 0.001) for ODI. EQ-VAS improved by 22 points (CI 15.4-30.3, P < 0.001) at follow-up. Approximately half of the patients achieved MCID and PASS for pain (MCID NRS LBP: 38/65 [59%] and PASS NRS LBP: 32/66 [49%]) and physical function (MCID ODI: 27/67 [40%] and PASS ODI: 24/67 [36%]). The odds for increasing the patient's walking distance to over 1 km at follow-up were 3.5 (CI 1.8-7.0; P < 0.0001), and of getting off full sick leave or full disability leave was 0.57 (CI 0.4-0.8; P = 0.001). In the first 3 months after surgery 3 complications were reported, and in the follow-up period 2 reoperations. CONCLUSION: We found moderate treatment outcomes after minimally invasive sacroiliac joint fusion when applied in daily practice with moderate pain relief and small improvements in physical function.

Long-term outcomes after surgery for subaxial cervical spine injuries in octogenarians, a matched population-based cohort study.

PURPOSE: We aimed to investigate surgical outcomes in octogenarians with subaxial cervical spine injuries and determine the predictors of complications and mortality. METHODS: Eligible for inclusion were all patients surgically treated between 2006 and 2018, with either anterior or posterior fixation for subaxial spine injuries. A cohort of octogenarians was identified and matched 1:1 to a corresponding cohort of younger adults. Primary outcomes were perioperative complications and mortality. RESULTS: Fifty-four patients were included in each of the octogenarian and younger groups (median age: 84.0 vs. 38.5). While the risks for surgical complications, including dural tears and wound infections, were similar between groups, the risks of postoperative medical complications, including respiratory or urinary tract infections, were significantly higher among the elderly (p < 0.05). Additionally, there were no differences in operative time (p = 0.625) or estimated blood loss (p = 0.403) between groups. The 30 and 90-day mortality rates were significantly higher among the elderly (p = 0.004 and p < 0.001). These differences were due to comorbidities in the octogenarian cohort as they were revoked when propensity score matching was performed to account for the differences in American Society of Anesthesiology (ASA) grade. Multivariable logistic regression revealed age and ASA score to be independent predictors of complications and the 90-day mortality, respectively. CONCLUSIONS: Octogenarians with comorbidities were more susceptible to postoperative complications, explaining the increased short-term mortality in this group. However, octogenarians without comorbidities had similar outcomes compared to the younger patients, indicating that overall health, including comorbidities, rather than chronological age should be considered in surgical decision-making.

Predictors of failure after primary anterior cervical discectomy and fusion for subaxial traumatic spine injuries.

INTRODUCTION: Traumatic subaxial fractures account for more than half of all cervical spine injuries. The optimal surgical approach is a matter of debate and may include anterior, posterior or a combined anteroposterior (360º) approach. Analyzing a cohort of patients initially treated with anterior cervical discectomy and fusion (ACDF) for traumatic subaxial injuries, the study aimed to identify predictors for treatment failure and the subsequent need for supplementary posterior fusion (PF). METHODS: A retrospective, single center, consecutive cohort study of all adult patients undergoing primary ACDF for traumatic subaxial cervical spine fractures between 2006 and 2018 was undertaken and 341 patients were included. Baseline clinical and radiological data for all included patients were analyzed and 11 cases of supplementary posterior fixation were identified. RESULTS: Patients were operated at a median of 2.0 days from the trauma, undergoing 1-level (78%), 2-levels (16%) and ≥ 3-levels (6.2%) ACDF. A delayed supplementary PF was performed in 11 cases, due to ACDF failure. On univariable regression analysis, older age (p = 0.017), shorter stature (p = 0.031), posterior longitudinal ligament (PLL) injury (p = 0.004), injury to ligamentum flavum (p = 0.005), bilateral facet joint dislocation (p < 0.001) and traumatic cervical spondylolisthesis (p = 0.003) predicted ACDF failure. On the multivariable regression model, older age (p = 0.015), PLL injury (p = 0.048), and bilateral facet joint dislocation (p = 0.010) remained as independent predictors of ACDF failure. CONCLUSIONS: ACDF is safe and effective for the treatment of subaxial cervical spine fractures. High age, bilateral facet joint dislocation and traumatic PLL disruption are independent predictors of failure. We suggest increased vigilance regarding these cases.

Extended reality in cranial and spinal neurosurgery - a bibliometric analysis.

PURPOSE: This bibliometric analysis of the top 100 cited articles on extended reality (XR) in neurosurgery aimed to reveal trends in this research field. Gender differences in authorship and global distribution of the most-cited articles were also addressed. METHODS: A Web of Science electronic database search was conducted. The top 100 most-cited articles related to the scope of this review were retrieved and analyzed for trends in publications, journal characteristics, authorship, global distribution, study design, and focus areas. After a brief description of the top 100 publications, a comparative analysis between spinal and cranial publications was performed. RESULTS: From 2005, there was a significant increase in spinal neurosurgery publications with a focus on pedicle screw placement. Most articles were original research studies, with an emphasis on augmented reality (AR). In cranial neurosurgery, there was no notable increase in publications. There was an increase in studies assessing both AR and virtual reality (VR) research, with a notable emphasis on VR compared to AR. Education, surgical skills assessment, and surgical planning were more common themes in cranial studies compared to spinal studies. Female authorship was notably low in both groups, with no significant increase over time. The USA and Canada contributed most of the publications in the research field. CONCLUSIONS: Research regarding the use of XR in neurosurgery increased significantly from 2005. Cranial research focused on VR and resident education while spinal research focused on AR and neuronavigation. Female authorship was underrepresented. North America provides most of the high-impact research in this area.

Reliability of thoracolumbar burst fracture classification in the Swedish Fracture Register.

BACKGROUND: The Swedish Fracture Register (SFR) is a national quality register for all types of fractures in Sweden. Spine fractures have been included since 2015 and are classified using a modified AOSpine classification. The aim of this study was to determine the accuracy of the classification of thoracolumbar burst fractures in the SFR. METHODS: Assessments of medical images were conducted in 277 consecutive patients with a thoracolumbar burst fracture (T10-L3) identified in the SFR. Two independent reviewers classified the fractures according to the AOSpine classification, with a third reviewer resolving disagreement. The combined results of the reviewers were considered the gold standard. The intra- and inter-rater reliability of the reviewers was determined with Cohen's kappa and percent agreement. The SFR classification was compared with the gold standard using positive predictive values (PPV), Cohen's kappa and percent agreement. RESULTS: The reliability between reviewers was  high (Cohen's kappa 0.70-0.97). The PPV for correctly classifying burst fractures in the SFR was high irrespective of physician experience (76-89%), treatment (82% non-operative, 95% operative) and hospital type (83% county, 95% university). The inter-rater reliability of B-type injuries and the overall SFR classification compared with the gold standard was low (Cohen's kappa 0.16 and 0.17 respectively). CONCLUSIONS: The SFR demonstrates a high PPV for accurately classifying burst fractures, regardless of physician experience, treatment and hospital type. However, the reliability of B-type injuries and overall classification in the SFR was found to be low. Future studies on burst fractures using SFR data where classification is important should include a review of medical images to verify the diagnosis.

Back morphology and walking patterns mean 13.8 years after surgery for lumbar disk herniation in adolescents.

Introduction: In many pain conditions, there is lingering pain despite healed tissue damage. Our previous study shows that individuals who underwent surgery for lumbar disk herniation (LDH) during adolescence have worse health, more pain, and increased disk degeneration mean 13 years after surgery compared with controls. It is unclear if walking patterns segregate surgically treated LDH adolescents and controls at mean 13-year follow-up. Objectives: Here, we analyzed the relationship between gait, back morphology and other health outcomes in a cohort of individuals treated surgically because of lumbar disk herniation compared with controls. Methods: We analyzed gait during a walking paradigm, back morphology at the site of surgery, and standardized health outcomes, among individuals who received surgery for LDH as adolescents, "cases" (n = 23), compared with "controls" (n = 23). Results: There were gait differences in head (P = 0.021) and trunk angle (P = 0.021) between cases and controls in a direction where cases exhibited a posture associated with sickness. The gait variance was explained by subjective pain and exercise habits rather than objective disk degeneration. Conclusion: Over a decade after surgery for LDH during adolescence, health among cases is worse compared with controls. The head and trunk angles differ between cases and controls, indicating that the residual pain lingers and may cause changes in movement patterns long after a painful episode in early life. Gait may be a useful target for understanding maintenance of pain and disability among individuals treated surgically for LDH during adolescence.

Lumbar degeneration and quality of life in patients with lumbar disc herniation: a case-control long-term follow-up study.

BACKGROUND AND PURPOSE: Adults treated surgically for lumbar disc herniation in adolescence have a higher degree of lumbar disc degeneration than controls. We aimed to establish whether the degree of lumbar degeneration differs at diagnosis or at follow-up between surgically and non-surgically treated individuals. METHODS: We identified individuals with a lumbar disc herniation in adolescence diagnosed with magnetic resonance imaging (MRI) and contacted them for follow-up MRI. Lumbar degeneration was assessed according to Pfirrmann, Modic, and total end plate score (TEP score). Patient-reported outcome measures at follow-up comprised the Oswestry Disability Index (ODI), EQ-5D-3-level version, 36-Item Short Form Health Survey (SF-36), and Visual Analogue Scale (VAS) for back and leg pain. Fisher's exact test, Mann-Whitney U tests, Wilcoxon tests, and logistic regression were used for statistical analysis. RESULTS: MRIs were available at diagnosis and after a mean of 11.9 years in 17 surgically treated individuals and 14 non-surgically treated individuals. Lumbar degeneration was similar at diagnosis (P = 0.2) and at follow-up, with the exception of higher TEP scores in surgically treated individuals at levels L4-L5 and L5-S1 at follow-up (P ≤ 0.03), but this difference did not remain after adjustment for age and sex (P ≥ 0.8). There were no significant differences in patient-reported outcome measures between the groups at follow-up (all P ≥ 0.2). CONCLUSION: Adolescents with a lumbar disc herniation have, irrespective of treatment, a similar degree of lumbar degeneration at the time of diagnosis, and similar lumbar degeneration and patient-reported outcomes at long-term follow-up.

The Effect of Concomitant Spinal Cord Injury on Postoperative Health-related Quality of Life After Traumatic Subaxial Cervical Spine Injuries: A Nationwide Registry Study.

OBJECTIVE: To evaluate the effect of spinal cord injury (SCI) on the health-related quality of life (HRQoL) in patients surgically treated for traumatic subaxial cervical spine injuries and investigate the agreement between objective neurologic outcomes and patient reported outcome measures (PROMs) in that context. STUDY DESIGN: Observational study on prospectively collected multi-institutional registry data. SETTING: Sweden. PARTICIPANTS: Patients with traumatic subaxial spine injuries identified in the Swedish Spine Registry (Swespine) between 2006 and 2016. INTERVENTIONS: Anterior, posterior, or anteroposterior cervical fixation surgery. MAIN OUTCOMES: Patient-reported outcome measures (PROMs) consisting of EQ-5D-3Lindex and Neck Disability Index (NDI). RESULTS: Among the 418 identified patients, 93 (22%) had a concomitant SCI. In this group, 30 (32%) had a complete SCI (Frankel A), and the remainder had incomplete SCIs (17%) Frankel B; 25 (27%) Frankel C; 22 (24%) Frankel D. PROMs significantly correlated with the Frankel grade (P<.001). However, post hoc analysis revealed that the differences between adjacent Frankel grades failed to reach both statistical and clinical significance. On univariable linear regression, the Frankel grade was a significant predictor of a specific index derived from the EQ-5D-3L questionnaire (EQ-5D-3Lindex) at 1, 2, and 5 years postoperatively as well as the NDI at 1 and 2 years postoperatively (P<.001). Changes of PROMs over time from 1, to 2, and 5 years postoperatively did not reach statistical significance, regardless of the presence and degree of SCI (P>.05). CONCLUSION: Overall, the Frankel grade significantly correlated with the EQ-5D-3Lindex and NDI and was a significant predictor of PROMs at 1, 2, and 5 years. PROMs were stable beyond 1 year postoperatively regardless of the severity of the SCI.

The effect of minimally invasive sacroiliac joint fusion compared to sham operation: a double-blind randomized placebo-controlled trial.

Background: Minimally invasive fusion of the sacroiliac joint as treatment for low back pain may reduce pain and improve function compared to non-operative treatment, although clear evidence is lacking. The aim of this trial was to evaluate the effect of minimally invasive sacroiliac joint fusion compared to sham surgery on sacroiliac joint pain reduction. Methods: In this double-blind randomized sham surgery-controlled trial patients with clinical diagnosis of sacroiliac joint pain confirmed with sacroiliac joint injection were included at two university hospitals in Sweden and Norway. Patients were randomized by the operating surgeon at each site to minimally invasive sacroiliac joint fusion or sham surgery. The primary endpoint was group difference in sacroiliac joint pain on the operated side at six months postoperatively, measured by the Numeric Rating Scale (0-10). Un-blinding and primary analysis were performed when all patients had completed six months follow-up. The trial is closed for new participants and was registered at clinicaltrials.gov: NCT03507049. Findings: Between September 1st, 2018 and October 22nd, 2021, 63 patients were randomized, 32 to the surgical group, 31 to the sham group. Mean age was 45 years (range 26-63) and 59 of 63 (94%) patients were female. The mean reduction in the operated sacroiliac joint from baseline to six months postoperative was 2.6 Numeric Rating Scale points in the surgical group and 1.7 points in the sham group (mean between groups difference -1.0 points; 95% CI, -2.2 to 0.3; p = 0.13). Interpretation: This double-blind randomized controlled trial could not prove that minimally invasive fusion of the sacroiliac joint was superior to sham surgery at six months postoperative. Funding: Sophies Minde Ortopedi supported a clinical research position for Engelke Marie Randers. Region Stockholm supported the cost for the Swedish ethical application and a clinical research appointment for Paul Gerdhem.

Dysphagia, health-related quality of life, and return to work after occipitocervical fixation.

PURPOSE: The purpose of this study was to evaluate patient-reported outcome measures (PROMS) on dysphagia, health-related quality of life (HRQoL) and return to work after occipitocervical fixation (OCF). Postoperative radiographic measurements were evaluated to identify possible predictors of dysphagia. METHODS: All individuals (≥ 18 years) who underwent an OCF at the study center or were registered in the Swedish spine registry (Swespine) between 2005 and 2019, and were still alive when the study was conducted, were eligible for inclusion. There was no overlap between the cohorts. Prospectively collected data on dysphagia (Dysphagia Short Questionnaire DSQ), HRQoL (EQ5D-3L) and return to work were used. Radiological and baseline patient data were retrospectively collected. In addition, HRQoL data of a matched sample of individuals was elicited from the Stockholm Public Health Survey 2006. RESULTS: In total, 54 individuals were included. At long-term follow-up, 26 individuals (51%) had no dysphagia, and 25 (49%) reported some degree of dysphagia: 11 (22%) had mild dysphagia, and 14 (27%) had moderate to severe dysphagia. On a group level, the OCF sample scored significantly lower EQVAS and EQ-5Dindex values compared to the general population (60.0 vs. 80.0, p = 0.016; 0.43 vs. 0.80, p < 0.001). Individuals working preoperatively returned to work after surgery. Of those responding, 88% stated that they would undergo the OCF operation if it was offered today. No predictors of dysphagia based on radiographic measurements were identified. CONCLUSION: Occipitocervical fixation results in a high frequency of long-term dysphagia. The HRQoL of OCF patients is significantly reduced compared to matched controls. However, most patients are satisfied with their surgery. No radiographic predictors of long-term dysphagia could be identified. Future prospective and systematic studies with larger samples and more objective outcome measures are needed to elucidate the causes of dysphagia in OCF.

Nighttime Bracing or Exercise in Moderate-Grade Adolescent Idiopathic Scoliosis: A Randomized Clinical Trial.

Importance: Moderate-grade adolescent idiopathic scoliosis (AIS) may be treated with full-time bracing. For patients who reject full-time bracing, the effects of alternative, conservative interventions are unknown. Objective: To determine whether self-mediated physical activity combined with either nighttime bracing (NB) or scoliosis-specific exercise (SSE) is superior to a control of physical activity alone (PA) in preventing Cobb angle progression in moderate-grade AIS. Design, Setting, and Participants: The Conservative Treatment for Adolescent Idiopathic Scoliosis (CONTRAIS) randomized clinical trial was conducted from January 10, 2013, through October 23, 2018, in 6 public hospitals across Sweden. Male and female children and adolescents aged 9 to 17 years with an AIS primary curve Cobb angle of 25° to 40°, apex T7 or caudal, and skeletal immaturity based on estimated remaining growth of at least 1 year were included in the study. Dates of analysis were from October 25, 2021, to January 28, 2023. Interventions: Interventions included self-mediated physical activity in combination with either NB or SSE or PA (control). Patients with treatment failure were given the option to transition to a full-time brace until skeletal maturity. Main Outcomes and Measures: The primary outcome was curve progression of 6° or less (treatment success) or curve progression of more than 6° (treatment failure) seen on 2 consecutive posteroanterior standing radiographs compared with the inclusion radiograph before skeletal maturity. A secondary outcome of curve progression was the number of patients undergoing surgery up until 2 years after the primary outcome. Results: The CONTRAIS study included 135 patients (45 in each of the 3 groups) with a mean (SD) age of 12.7 (1.4) years; 111 (82%) were female. Treatment success was seen in 34 of 45 patients (76%) in the NB group and in 24 of 45 patients (53%) in the PA group (odds ratio [OR], 2.7; 95% CI, 1.1-6.6). The number needed to treat to prevent curve progression with NB was 4.5 (95% CI, 2.4-33.5). Treatment success occurred in 26 of 45 patients (58%) in the SSE group (OR for SE vs PA, 1.2; 95% CI, 0.5-2.8). Up to 2 years after the primary outcome time point, 9 patients in each of the 3 groups underwent surgery. Conclusions and Relevance: In this randomized clinical trial, treatment with NB prevented curve progression of more than 6° to a significantly higher extent than did PA, while SSE did not; in addition, allowing transition to full-time bracing after treatment failure resulted in similar surgical frequencies independent of initial treatment. These results suggest that NB may be an effective alternative intervention in patients rejecting full-time bracing. Trial Registration: ClinicalTrials.gov Identifier: NCT01761305.

Association of genetic variation in COL11A1 with adolescent idiopathic scoliosis.

Adolescent idiopathic scoliosis (AIS) is a common and progressive spinal deformity in children that exhibits striking sexual dimorphism, with girls at more than fivefold greater risk of severe disease compared to boys. Despite its medical impact, the molecular mechanisms that drive AIS are largely unknown. We previously defined a female-specific AIS genetic risk locus in an enhancer near the PAX1 gene. Here, we sought to define the roles of PAX1 and newly identified AIS-associated genes in the developmental mechanism of AIS. In a genetic study of 10,519 individuals with AIS and 93,238 unaffected controls, significant association was identified with a variant in COL11A1 encoding collagen (α1) XI (rs3753841; NM_080629.2_c.4004C>T; p.(Pro1335Leu); p=7.07E-11, OR = 1.118). Using CRISPR mutagenesis we generated Pax1 knockout mice (Pax1-/-). In postnatal spines we found that PAX1 and collagen (α1) XI protein both localize within the intervertebral disc-vertebral junction region encompassing the growth plate, with less collagen (α1) XI detected in Pax1-/- spines compared to wild-type. By genetic targeting we found that wild-type Col11a1 expression in costal chondrocytes suppresses expression of Pax1 and of Mmp3, encoding the matrix metalloproteinase 3 enzyme implicated in matrix remodeling. However, the latter suppression was abrogated in the presence of the AIS-associated COL11A1P1335L mutant. Further, we found that either knockdown of the estrogen receptor gene Esr2 or tamoxifen treatment significantly altered Col11a1 and Mmp3 expression in chondrocytes. We propose a new molecular model of AIS pathogenesis wherein genetic variation and estrogen signaling increase disease susceptibility by altering a PAX1-COL11a1-MMP3 signaling axis in spinal chondrocytes.

Adolescent idiopathic scoliosis (AIS) is a twisting deformity of the spine that occurs during periods of rapid growth in children worldwide. Children with severe cases of AIS require surgery to stop it from getting worse, presenting a significant financial burden to health systems and families. Although AIS is known to cluster in families, its genetic causes and its inheritance pattern have remained elusive. Additionally, AIS is known to be more prevalent in females, a bias that has not been explained. Advances in techniques to study the genetics underlying diseases have revealed that certain variations that increase the risk of AIS affect cartilage and connective tissue. In humans, one such variation is near a gene called Pax1, and it is female-specific. The extracellular matrix is a network of proteins and other molecules in the space between cells that help connect tissues together, and it is particularly important in cartilage and other connective tissues. One of the main components of the extracellular matrix is collagen. Yu, Kanshour, Ushiki et al. hypothesized that changes in the extracellular matrix could affect the cartilage and connective tissues of the spine, leading to AIS. To show this, the scientists screened over 100,000 individuals and found that AIS is associated with variants in two genes coding for extracellular matrix proteins. One of these variants was found in a gene called Col11a1, which codes for one of the proteins that makes up collagen. To understand the relationship between Pax1 and Col11a1, Yu, Kanshour, Ushiki et al. genetically modified mice so that they would lack the Pax1 gene. In these mice, the activation of Col11a1 was reduced in the mouse spine. They also found that the form of Col11a1 associated with AIS could not suppress the activation of a gene called Mmp3 in mouse cartilage cells as effectively as unmutated Col11a1. Going one step further, the researchers found that lowering the levels of an estrogen receptor altered the activation patterns of Pax1, Col11a1, and Mmp3 in mouse cartilage cells. These findings suggest a possible mechanism for AIS, particularly in females. The findings of Yu, Kanshour, Ushiki et al. highlight that cartilage cells in the spine are particularly relevant in AIS. The results also point to specific molecules within the extracellular matrix as important for maintaining proper alignment in the spine when children are growing rapidly. This information may guide future therapies aimed at maintaining healthy spinal cells in adolescent children, particularly girls.

Assessment of the sacroiliac joint with computed tomography motion analysis: a diagnostic study of 12 patients.

BACKGROUND AND PURPOSE: Pain in the sacroiliac joint may be caused by abnormal joint motion. Diagnosis is mainly based on clinical tests. The aims of this study were to examine whether low-dose computed tomography with provocation of the hip could detect sacroiliac joint motion, and to study whether provocation of the hip results in greater sacroiliac joint motion in the ipsilateral than in the contralateral sacroiliac joint. PATIENTS AND METHODS: 12 patients with sacroiliac joint pain were examined with low-dose computed tomography scans of the sacroiliac joint, one with the hips in the neutral position, and one each in provocation with the left or the right hip in a figure-of-4 position. Accuracy was tested by comparing internal rotation of the sacrum with internal rotation in the sacroiliac joint. Motion in the sacroiliac joint was assessed by comparing the position of each of the ilia with the reference, the sacrum. Data is shown as mean with 95% confidence interval (CI). RESULTS: We observed greater motion in the sacroiliac joint than internally in the sacrum, i.e., 0.57° (CI 0.43-0.71) vs. 0.20° (CI 0.11-0.28). The motion of the geometric center of the moving object for the sacroiliac joint was larger on the provoked side; mean difference 0.17 mm (CI 0.01-0.33), P = 0.04. Corresponding figures for rotation were mean difference 0.19° (CI 0.10-0.28), P < 0.001. Compared with the sacrum, the largest motion was seen at the anterior superior iliac spine; mean difference 0.38 mm (CI 0.10-0.66), P = 0.001. CONCLUSION: Provocation in the figure-of-4 position of the hip results in sacroiliac joint motion measurable with computed tomography motion analysis. Provocation of the hip induces larger motion on the ipsilateral than on the contralateral sacroiliac joint.

Spinal surgery and the risk of reoperation after total hip arthroplasty: a cohort study based on Swedish spine and hip arthroplasty registers.

BACKGROUND AND PURPOSE: Studies suggest increased revision risk of total hip arthroplasty (THA) in individuals with lumbar spinal fusion, but studies including non-fused individuals are lacking. We aimed to investigate whether individuals undergoing lumbar spinal stenosis surgery with or without fusion are at an increased risk of reoperation before or after THA. PATIENTS AND METHODS: The Swedish Spine Register and the Swedish arthroplasty register were searched from 2000 through 2021. Chi-square, Kaplan-Meier and binary multivariate logistic regression were used to compare reoperation rates up to 10 years after THA surgery. RESULTS: 7,908 individuals had undergone lumbar spinal stenosis surgery (LSSS) (fusion n = 1,281) and THA. LSSS before THA compared with THA-only controls was associated with a higher risk of THA reoperations: 87 (2%) out of 3,892 vs. 123 (1%) out of 11,662 (P < 0.001). LSSS after THA compared with THA-only controls was not associated with a higher risk of reoperation, confirmed by Kaplan- Meier analyses and binary multivariate logistic regression. Mortality was lower in individuals undergoing both LSSS and THA, regardless of procedure order. There was no difference in THA reoperations in individuals who had undergone LSSS before THA without fusion or with fusion. The individuals who had undergone LSSS after THA with fusion had an increased risk of THA reoperation compared with those without fusion. CONCLUSION: LSSS with or without fusion before THA is associated with an increased risk of THA reoperation. Spinal fusion increased the risk of reoperation of THA when performed after THA.

Correction: Dufvenberg et al. Six-Month Results on Treatment Adherence, Physical Activity, Spinal Appearance, Spinal Deformity, and Quality of Life in an Ongoing Randomised Trial on Conservative Treatment for Adolescent Idiopathic Scoliosis (CONTRAIS). J. Clin. Med. 2021, 10, 4967.

In the original publication [...].

Magnetically controlled growing rod treatment for early-onset scoliosis: analysis of 52 consecutive cases demonstrates improvement of coronal deformity.

Background: The purpose of this study was to report the radiographic results and complications of magnetically controlled growing rod (MCGR) treatment in patients with early-onset scoliosis (EOS). Methods: Patient records and radiographs from a consecutive series of patients treated with MCGR for EOS at two Swedish institutions were reviewed retrospectively. Radiographic analysis included Cobb angle, T1-T12 height, T1-S1 height, thoracic kyphosis, and lung height. Subgroup analyses were performed on primary versus conversion cases and single versus dual rods using one-way analysis of variance (ANOVA) and independent samples t-test. Results: Fifty-two cases treated with MCGR (24 single rods, 28 dual rods) were included from local surgical records into this cohort study, 32 primary and 20 converted from other growth friendly surgical treatment. Mean age at MCGR implantation was 7.4 (2.0-14.6) years old in the primary group and 9.3 (5.0-16.1) years old in the converted group. Mean follow-up time was 3.7 (2.0-7.6) years. Mean (standard deviation; SD) Cobb angle of the major curve changed from 62° (17°) preoperatively to 42° (16°) postoperatively to 46° (18°) at final follow-up (P<0.001). Mean (SD) overall thoracic kyphosis changed from 41° (19°) preoperatively to 32° (14°) postoperatively to 39° (17°) at final follow-up (P=0.018). Mean T1-T12 height was 177 mm (34 mm) preoperatively, 183 mm (35 mm) immediate postoperative and 199 mm (35 mm) at final follow-up (P=0.047). The mean T1-T12 height increased significantly in the primary group but not in the converted group. The number of surgeries was 114 (78 planned, 36 unplanned). The rate of unplanned surgeries did not differ significantly between single and dual rods. The total number of complications was 70 of which 38 were implant related. The overall mean complication rate was 1.4 (0-4). There were no significant differences in complication rates between subgroups. Conclusions: MCGR treatment enabled and maintained correction of spinal deformity while allowing spinal growth. There were no significant differences in complication rates or unplanned surgeries between the groups treated with single or dual rods.

Minimally Invasive Surgery for Thoracolumbar Spinal Fractures in Patients With Ankylosing Spondylitis.

BACKGROUND: Patients with ankylosing spondylitis (AS) are prone to spinal fractures even after low-energy trauma. Posterior fusion through open surgery has been the standard procedure for spinal fractures in patients with AS. Minimally invasive surgery (MIS) has been proposed as an alternative treatment option. There are few literature reports regarding patients with AS being treated for spinal fractures with MIS. This study aims to present the clinical outcome of a series of patients with AS treated with MIS for spinal fractures. METHODS: We included a consecutive series of patients with AS who underwent MIS for thoracolumbar fractures between 2014 and 2021. The median follow-up was 38 (12-75) months. Medical records and radiographs were reviewed, and data on surgery, reoperations, complications, fracture healing, and mortality were recorded. RESULTS: Forty-three patients (39 [91%] men) were included with a median (range) age of 73 (38-89) years. All patients underwent image-guided MIS with screws and rods. Three patients underwent reoperations, all due to wound infections. One patient (2%) died within 30 days and 7 (16%) died within the first year after surgery. Most patients with a radiographic follow-up of 12 months or more (29/30) healed with a bony fusion on computed tomography (97%). CONCLUSION: Patients with AS and a spinal fracture are at risk of reoperation and have significant mortality during the first year. MIS provides adequate surgical stability for fracture healing with an acceptable number of complications and is an adequate choice in treating AS-related spinal fractures.

Association of genetic variation in COL11A1 with adolescent idiopathic scoliosis.

Adolescent idiopathic scoliosis (AIS) is a common and progressive spinal deformity in children that exhibits striking sexual dimorphism, with girls at more than five-fold greater risk of severe disease compared to boys. Despite its medical impact, the molecular mechanisms that drive AIS are largely unknown. We previously defined a female-specific AIS genetic risk locus in an enhancer near the PAX1 gene. Here we sought to define the roles of PAX1 and newly-identified AIS-associated genes in the developmental mechanism of AIS. In a genetic study of 10,519 individuals with AIS and 93,238 unaffected controls, significant association was identified with a variant in COL11A1 encoding collagen (α1) XI (rs3753841; NM_080629.2_c.4004C>T; p.(Pro1335Leu); P=7.07e-11, OR=1.118). Using CRISPR mutagenesis we generated Pax1 knockout mice (Pax1-/-). In postnatal spines we found that PAX1 and collagen (α1) XI protein both localize within the intervertebral disc (IVD)-vertebral junction region encompassing the growth plate, with less collagen (α1) XI detected in Pax1-/- spines compared to wildtype. By genetic targeting we found that wildtype Col11a1 expression in costal chondrocytes suppresses expression of Pax1 and of Mmp3, encoding the matrix metalloproteinase 3 enzyme implicated in matrix remodeling. However, this suppression was abrogated in the presence of the AIS-associated COL11A1P1335L mutant. Further, we found that either knockdown of the estrogen receptor gene Esr2, or tamoxifen treatment, significantly altered Col11a1 and Mmp3 expression in chondrocytes. We propose a new molecular model of AIS pathogenesis wherein genetic variation and estrogen signaling increase disease susceptibility by altering a Pax1-Col11a1-Mmp3 signaling axis in spinal chondrocytes.