Assessing the Reproducibility of the Structured Abstracts Generated by ChatGPT and Bard Compared to Human-Written Abstracts in the Field of Spine Surgery: Comparative Analysis.

BACKGROUND: Due to recent advances in artificial intelligence (AI), language model applications can generate logical text output that is difficult to distinguish from human writing. ChatGPT (OpenAI) and Bard (subsequently rebranded as "Gemini"; Google AI) were developed using distinct approaches, but little has been studied about the difference in their capability to generate the abstract. The use of AI to write scientific abstracts in the field of spine surgery is the center of much debate and controversy. OBJECTIVE: The objective of this study is to assess the reproducibility of the structured abstracts generated by ChatGPT and Bard compared to human-written abstracts in the field of spine surgery. METHODS: In total, 60 abstracts dealing with spine sections were randomly selected from 7 reputable journals and used as ChatGPT and Bard input statements to generate abstracts based on supplied paper titles. A total of 174 abstracts, divided into human-written abstracts, ChatGPT-generated abstracts, and Bard-generated abstracts, were evaluated for compliance with the structured format of journal guidelines and consistency of content. The likelihood of plagiarism and AI output was assessed using the iThenticate and ZeroGPT programs, respectively. A total of 8 reviewers in the spinal field evaluated 30 randomly extracted abstracts to determine whether they were produced by AI or human authors. RESULTS: The proportion of abstracts that met journal formatting guidelines was greater among ChatGPT abstracts (34/60, 56.6%) compared with those generated by Bard (6/54, 11.1%; P<.001). However, a higher proportion of Bard abstracts (49/54, 90.7%) had word counts that met journal guidelines compared with ChatGPT abstracts (30/60, 50%; P<.001). The similarity index was significantly lower among ChatGPT-generated abstracts (20.7%) compared with Bard-generated abstracts (32.1%; P<.001). The AI-detection program predicted that 21.7% (13/60) of the human group, 63.3% (38/60) of the ChatGPT group, and 87% (47/54) of the Bard group were possibly generated by AI, with an area under the curve value of 0.863 (P<.001). The mean detection rate by human reviewers was 53.8% (SD 11.2%), achieving a sensitivity of 56.3% and a specificity of 48.4%. A total of 56.3% (63/112) of the actual human-written abstracts and 55.9% (62/128) of AI-generated abstracts were recognized as human-written and AI-generated by human reviewers, respectively. CONCLUSIONS: Both ChatGPT and Bard can be used to help write abstracts, but most AI-generated abstracts are currently considered unethical due to high plagiarism and AI-detection rates. ChatGPT-generated abstracts appear to be superior to Bard-generated abstracts in meeting journal formatting guidelines. Because humans are unable to accurately distinguish abstracts written by humans from those produced by AI programs, it is crucial to exercise special caution and examine the ethical boundaries of using AI programs, including ChatGPT and Bard.

Proximal junctional kyphosis after adult spinal deformity operated patients with long fusion to the pelvis. Does the type of proximal anchor matter?

PURPOSE: To assess, in a large population of Adult Spinal Deformity (ASD) patients, the true interest of varying the upper anchors as a protective measure against Proximal Junctional Kyphosis (PJK), by analyzing and comparing 2 groups of patients defined according to their proximal construct. Another objective of the study is to look for any other factors, radiological or clinical, that would affect the occurrence of the proximal failure. METHODS: Retrospective review of a prospective ASD database collected from 5 centers. Inclusion criteria were age of at least 18 years, presence of a spinal deformity with instrumentation from T12 or above to the pelvis, with minimum 2 years of follow-up. Demographic data, spinopelvic parameters, functional outcomes and complications were collected. Multiple logistic regression analysis was performed to identify the risk factors that would affect the occurrence of PJK. RESULTS: 254 patients were included. 166 in the group "screws proximally" (SP) and 88 in the group "hooks proximally" (HP). There was no difference between both groups for PJK (p = 0.967). The occurrence of PJK was rather associated with greater age and BMI, higher preoperative kyphosis, worst preoperative SRS22 and SF36 scores, greater postoperative Sagittal Vertical Axis (SVA), coronal malalignment and kyphosis. CONCLUSION: The use of proximal hooks was not effective to prevent PJK after ASD surgery, when compared to proximal screws. Worse preoperative functional outcomes and worse postoperative sagittal and also coronal malalignment were the main drivers for the occurrence of PJK regardless the type of proximal implant.

Calculation of the minimal clinically important difference in operated patients with adult spine deformity: advantages of the ROC method and significance of prevalence in threshold selection.

PURPOSE: The Minimal Clinically Important Difference (MCID) is crucial to evaluate management outcomes, but different thresholds have been obtained in different works. Part of this variability is due to measurement error and influence of the database, both essential for calculating the MCID. The aim of this study was to introduce the association of the ROC method in the anchor-based MCID calculation for ODI, SRS-22r, and SF-36, to objectively set the threshold for the anchor-based MCID in an adult spine deformity (ASD) population. METHODS: Multicentric study based on a prospective database of consecutively operated ASD patients. An anchor question was used to assess patients' quality of life after surgery. Different approaches were used to calculate the MCID and then compared: SEM (Standard Error of Measurement), MDC (Minimal Detectable Change), and anchor-based MCID with ROC method. RESULTS: 516 patients were included. Those who responded with 6 and 7 to the anchor question were considered improved. The MCID ranges obtained with the ROC method exhibited the lowest variability. Prediction error rates ranged from 31% (SRS-22r) to 41% (SF-36 MCS). The MCID ranges spanned between 12 and 15 for ODI, 0.6 and 0.73 for SRS-22r, 6.62 and 7.41 for SF-36 PCS, and between 2.69 and 5.63 for SF-36 MCS. CONCLUSION: The ROC method proposes an MCID range with error rate, and can objectively determine the threshold for distinguishing improved and non-improved patients. As the MCID correlates with the utilized database and error of measurement, each study should compute its own MCID for each PROM to allow comparison among different publications. LEVEL OF EVIDENCE: II.

Which sagittal plane assessment method is most predictive of complications after adult spinal deformity surgery?

PURPOSE: Different methods of sagittal alignment assessment compete for predicting adverse events after adult spinal deformity (ASD) surgery. We wanted to study which method provides greater benefit. METHODS: Retrospective study of 391 patients operated for ASD, with > 6 instrumented levels, fused to the pelvis, and 2 years of follow-up. Three alignment methods were analyzed 6-week postoperatively: (1) Roussouly mismatch; (2) GAP score/GAP categories; (3) T4-L1-Hip axis. Binary logistic regression generated models that best predict the following adverse events: mechanical complications (MC): in general and isolated (PJK, PJF, rod breakage); reinterventions (in general and after MC); and readmissions. ROC/AUC analysis was also implemented. In a second regression round, we added different variables that were selected on univariate analysis-demographic, surgical, and radiographic-to complete the models. RESULTS: The best predictor parameters in most models were T4-L1PA mismatch and GAP score; we could not prove a predictive ability of the Roussouly mismatch. The T4-L1PA mismatch best predicted general MC, PJK, PJK + PJF, and readmission, while the GAP score best predicted PJF and reinterventions (for MC and for any complication). However, the variance explained by these models was limited (Nagelkerke's R2 = 0.031-0.113), with odds ratios ranging from 1.070 to 1.456. ROC curves plotted an AUC between 0.57 and 0.70. Introducing additional variables (demographic, surgical, and radiographic) improved prediction in all the models (Nagelkerke's R2 = 0.082-0.329) and allowed predicting rod breakage. CONCLUSION: The T4-L1-Hip axis and GAP score show potential in predicting adverse events, surpassing the Roussouly method. Despite partial efficacy in complication anticipation, recognizing postoperative sagittal alignment as a key modifiable risk factor, the crucial need arises to integrate diverse variables, both modifiable and non-modifiable, for enhanced predictive accuracy. LEVEL OF EVIDENCE: Level IV.

The Impact of Unplanned Reoperation Following Adult Spinal Deformity Surgery: A Prospective Longitudinal Cohort Study with 5-Year Follow-up.

BACKGROUND: The long-term impact of reoperations following adult spinal deformity (ASD) surgery is still poorly understood. Our aim was to identify the relationship between unplanned reoperation and health-related quality of life (HRQoL) gain at 2 and 5 years of follow-up. METHODS: We included patients enrolled in a prospective ASD database who underwent surgery ≥5 years prior to the start of the study and who had 2 years of follow-up data. Adverse events (AEs) leading to an unplanned reoperation, the time of reoperation occurrence, invasiveness (blood loss, surgical time, hospital stay), and AE resolution were assessed. HRQoL was measured with use of the Oswestry Disability Index, Scoliosis Research Society-22, and Short Form-36. Linear models controlling for baseline data and index surgery characteristics were utilized to assess the relationships between HRQoL gain at 2 and 5-year follow-up and the number and invasiveness of reoperations. The association between 5-year HRQoL gain and the time of occurrence of the unplanned reoperation and that between 5-year HRQoL gain and AE resolution were also investigated. RESULTS: Of 361 eligible patients, 316 (87.5%) with 2-year follow-up data met the inclusion criteria and 258 (71.5%) had 5-year follow-up data. At the 2-year follow-up, 96 patients (30.4%) had a total of 165 unplanned reoperations (1.72 per patient). At the 5-year follow-up, 73 patients (28.3%) had a total of 117 unplanned reoperations (1.60 per patient). The most common cause of reoperations was mechanical complications (64.9%), followed by surgical site infections (15.7%). At the 5-year follow-up, the AE that led to reoperation was resolved in 67 patients (91.8%). Reoperation invasiveness was not associated with 5-year HRQoL scores. The number of reoperations was associated with lesser HRQoL gain at 5 years for all HRQoL measures. The mean associated reduction in HRQoL gain per unplanned reoperation was 41% (range, 19% to 66%). Reoperations resulting in no resolution of the AE or resolution with sequelae had a greater impact on 5-year follow-up HRQoL scores than reoperations resulting in resolution of the AE. CONCLUSIONS: A postoperative, unplanned reoperation following ASD surgery was associated with lesser gain in HRQoL at 5 years of follow-up. The association did not diminish over time and was affected by the number, but not the magnitude, of reoperations. Resolution of the associated AE reduced the impact of the unplanned reoperation. LEVEL OF EVIDENCE: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

What factors are associated with a better restoration of pelvic version after adult spinal deformity surgery?

INTRODUCTION: Poor restoration of pelvic version after adult spinal deformity (ASD) surgery is associated with an increased risk of mechanical complications and worse quality of life. We studied the factors linked to the improvement of postoperative pelvic version. MATERIALS AND METHODS: This is a retrospective analysis of a prospective multicenter ASD database. Selection criteria were: operated patients having preoperative severe pelvic retroversion as per GAP score (Relative Pelvic Version-RPV < - 15°); panlumbar fusions to the pelvis; 2-year follow-up. Group A comprised patients with any postoperative improvement of RPV score, and group B had no improvement. Groups were compared regarding baseline characteristics, surgical factors, and postoperative sagittal parameters. Parametric and non-parametric analyses were employed. RESULTS: 177 patients were studied, median age 67 years (61; 72.5), 83.6% female. Groups were homogeneous in baseline demographics, comorbidities, and preoperative sagittal parameters (p > 0.05). The difference in RPV improvement was 11.56º. Group A (137 patients) underwent a higher percentage of ALIF procedures (OR = 6.66; p = 0.049), and posterior osteotomies (OR = 4.96; p < 0.001) especially tricolumnar (OR = 2.31; p = 0.041). It also showed a lower percentage of TLIF procedures (OR = 0.45; p = 0.028), and posterior decompression (OR = 0.44; p = 0.024). Group A displayed better postoperative L4-S1 angle and relative lumbar lordosis (RLL), leading to improved sacral slope (and RPV), and global alignment (RSA). Group A patients had longer instrumentations (11.45 vs 10; p = 0.047) and hospitalization time (13 vs 11; p = 0.045). All postoperative sagittal parameters remained significantly better in group A through follow-up. However, differences between the groups narrowed over time. CONCLUSIONS: ALIF procedures and posterior column osteotomies improved pelvic version postoperatively, and associated better L4-S1 and lumbar lordosis restoration, indirectly improving all other sagittal parameters. However, these improvements seemed to fade during the 2-year follow-up.

Back Pain in Adolescents and Young Adults with Idiopathic Scoliosis-Identifying Factors Associated with Significant Pain-A Multivariate Logistic Regression Analysis.

(1) Background: Previous data show that patients with idiopathic scoliosis (IS) can be classified into two groups according to pain intensity. This paper aims to determine which factors can independently predict the likelihood of belonging to a high-level pain group. (2) Methods: The study used a prospective, multicenter, cross-sectional design. Two-hundred and seventy-two patients with IS (mean age 18.1 years) (females 83.5%) were included. The sample was divided into two groups. The PAIN group comprised 101 patients (37.1%) with an average NRS of 5.3. The NO-PAIN group consisted of 171 patients (62.9%) with an average NRS of 1.1. Data on various factors such as comorbidities, family history, curve magnitude, type of treatment, absenteeism, anxiety, depression, kinesiophobia, family environment, and social relationships were collected. Statistical analysis consisted of multivariate logistic regression analysis to identify independent predictors of high-level pain. (3) Results: In the final model, including modifiable and non-modifiable predictors, age (OR 1.07 (1.02-1.11)); Absenteeism (OR 3.87 (1.52-9.87)), HAD anxiety (OR 1.18 (1.09-1.29)) and an indication for surgery (OR 2.87 (1.28-6.43)) were associated with an increased risk of pain. The overall model is significant at p = 0.0001 level and correctly predicts 72.6% of the responses. (4) Conclusions: Age, an indication for surgery, anxiety, and work/school absenteeism are the variables that independently determine the risk of belonging to the high-level pain group (NRS > 3).

Reliability of a New Digital Tool for Photographic Analysis in Quantifying Body Asymmetry in Scoliosis.

Background: Advancements in non-ionizing methods for quantifying spinal deformities are crucial for assessing and monitoring scoliosis. In this study, we analyzed the observer variability of a newly developed digital tool for quantifying body asymmetry from clinical photographs. Methods: Prospective observational multicenter study. Initially, a digital tool was developed using image analysis software, calculating quantitative measures of body asymmetry. This tool was integrated into an online platform that exports data to a database. The tool calculated 10 parameters, including angles (shoulder height, axilla height, waist height, right and left waistline angles, and their difference) and surfaces of the left and right hemitrunks (shoulders, waists, pelvises, and total). Subsequently, an online training course on the tool was conducted for twelve observers not involved in its development (six research coordinators and six spine surgeons). Finally, 15 standardized back photographs of adolescent idiopathic scoliosis patients were selected from a multicenter image bank, representing various clinical scenarios (different age, gender, curve type, BMI, and pre- and postoperative images). The 12 observers measured the photographs at two different times with a three-week interval. For the second round, the images were randomly mixed. Inter- and intra-observer variabilities of the measurements were analyzed using intraclass correlation coefficients (ICCs), and reliability was measured by the standard error of measurement (SEM). Group comparisons were made using Student's t-test. Results: The mean inter-observer ICC for the ten measurements was 0.981, the mean intra-observer ICC was 0.937, and SEM was 0.3-1.3°. The parameter with the strongest inter- and intra-observer validity was the difference in waistline angles 0.994 and 0.974, respectively, while the highest variability was found with the waist height angle 0.963 and 0.845, respectively. No test-retest differences (p > 0.05) were observed between researchers (0.948 ± 0.04) and surgeons (0.925 ± 0.05). Conclusion: We developed a new digital tool integrated into an online platform demonstrating excellent reliability and inter- and intra-observer variabilities for quantifying body asymmetry in scoliosis patients from a simple clinical photograph. The method could be used for assessing and monitoring scoliosis and body asymmetry without radiation.

The Mid-term Outcome of Intervertebral Disc Degeneration after Direct Vertebral Rotation in Adolescent Idiopathic Scoliosis: Magnetic Resonance Imaging-based Analysis for a Mean 11.6-year Follow-up.

STUDY DESIGN: A retrospective cohort study. OBJECTIVE: To evaluate the mid-term effect of intervertebral disc degeneration (DD) in adolescent idiopathic scoliosis (AIS) patients who underwent pedicle screw instrumentation (PSI) and rod derotation (RD) with direct vertebral rotation (DVR). SUMMARY OF BACKGROUND DATA: Posterior spinal fusion is a mainstay of surgical treatment in AIS, and DVR is considered a main corrective maneuver for vertebral rotation. However, the mid-term effect of intervertebral DD after DVR is still unknown in AIS. METHODS: A total of 336 vertebrae for 48 AIS patients who underwent PSI and RD with DVR were retrospectively assessed for intervertebral DD. They were divided into two groups based upon intervertebral DD, defined as Pfirmann grade more than IV. The Pfirrmann grade and modic change were evaluated at the disc above the uppermost instrumented vertebra (UIV), the disc below the lowest instrumented vertebra (LIV), and the lumbar disc levels. RESULTS: With the 11.6 years of mean follow-up, 41.7% (20/48) of patients exhibited DD, while modic changes were observed in 4.2% (2/48) of included patients. The disc below the LIV, L4-5, and L5-S1 were significantly shown to have an increasing trend of Pfirmann grade. The preoperative thoracic kyphosis was significantly lower in the DD group (22.0°) than in the non-DD group (31.4°) (P = 0.025) and negatively correlated with DD (r = -0.482, P = 0.018). The Pfirrmann grade of L5-S1 showed a high level of correlation with DD (r = 0.604, P < 0.001). CONCLUSIONS: The degenerative change at the disc below the LIV, L4-5, and L5-S1 levels was observed following PSI and RD with DVR. Thoracic hypokyphosis may negatively influence intervertebral discs in AIS patients required for deformity correction. Therefore, restoration of thoracic kyphosis is important to prevent long-term DD in AIS.

How frequently MRI modifies thoracolumbar fractures' classification or decision-making? A systematic review and meta-analysis.

PURPOSE: To provide the first meta-analysis of the impact of magnetic resonance imaging (MRI) on thoracolumbar fractures (TLFs) classification and decision-making. METHODS: A systematic review was conducted following PRISMA guidelines. We searched PubMed, Scopus, Cochrane, and Web of Science from inception to June 30, 2023 for studies evaluating the change in TLFs classification and treatment decisions after MRI. The studies extracted key findings, objectives, and patient population. A meta-analysis was performed for the pooled frequency of change in AO fracture classification or treatment decisions from surgical to conservative or vice versa after MRI. RESULTS: This meta-analysis included four studies comprising 554 patients. The pooled frequency of change in TLFs classification was 17% (95% CI 9-31%), and treatment decision was 22% (95% CI 11-40%). An upgrade from type A to type B was reported in 15.7% (95% CI 7.2-30.6%), and downgrading type B to type A in 1.2% (95% CI 0.17-8.3%). A change from conservative to surgery recommendation of 17% (95% CI 5.0-43%) was higher than a change from surgery to conservative 2% (95% CI 1-34%). CONCLUSIONS: MRI can significantly change the thoracolumbar classification and decision-making, primarily due to upgrading type A to type B fractures and changing from conservative to surgery, respectively. These findings suggest that MRI could change decision-making sufficiently to justify its use for TLFs. Type A subtypes, indeterminate PLC status, and spine regions might help to predict a change in TLFs' classification. However, more studies are needed to confirm the association of these variables with changes in treatment decisions to set the indications of MRI in neurologically intact patients with TLFs. An interactive version of our analysis can be accessed from here: https://databoard.shinyapps.io/mri_spine/ .

Primary Pelvic Anteversion: Definition, Relevance And History After Surgery for Adult Spine Deformity.

STUDY DESIGN: Retrospective analysis of prospectively collected data. OBJECTIVE: To identify the best definition of primary anteverted pelvis in the setting of adult spine deformity (ASD), and to investigate whether this is a pathologic setting that requires surgical correction. SUMMARY OF BACKGROUND DATA: While pelvic retroversion has been thoroughly investigated, pelvic anteversion (AP) is a far lesser discussed topic. Four different AP definitions have been proposed, and AP has been described as a normal or pathologic entity by different authors. METHODS: All patients consulting for ASD at the five participating sites were included. Firstly, the four definitions of AP were compared with descriptive statistics (anatomic method - Pelvic Tilt <0°; Relative Pelvic Version method - RPV >5°; Roussouly method - Pelvic Incidence (PI)<50° and Sacral Slope (SS)>35°); low PT method - PT/PI <25th percentile). Secondly a subgroup analysis among operated AP patients with a two-year follow-up was performed. Complication rate, radiographic parameters and clinical scores (ODI, SF-36) were compared in a multivariate analysis between patients who did and did not maintain an AP at the 2-year follow-up. RESULTS: 1163 patients were available for the first analysis. The RPV method appeared to be the most appropriate to define AP in ASD patient. For the second analysis, data on 410 subjects were available, and most of them were young adults with idiopathic scoliosis that did not require pelvic fixation. AP patients who maintained an AP after ASD surgery presented comparable radiographic and clinical outcomes to the patients who presented a normo/retroverted pelvis after surgery. CONCLUSIONS: According to the results of the presented study, the RPV method is the most appropriate to define primary AP, which is not a pathologic condition and is most often observed in young adults with idiopathic scoliosis. Anteverted pelvis does not require direct surgical correction in this patient group.

The reunion with my patients: their journey and experience 30 years after their intervention for adolescent idiopathic scoliosis via CD instrumentation.

PURPOSE: Our objective was to collect the experience and current attitude of those patients, now adults, operated on for adolescent idiopathic scoliosis (AIS) more than 25 years ago with CD instrumentation (CDI). METHODS: Prospective qualitative cross-sectional study with interpretive phenomenological analysis approach of AIS patients operated in a single center with CDI between 1985 and 1995. Patients underwent a semi-structured interview with their original surgeon. Seven agreed themes were open for conversation, and several subthemes emerged related to their experience during their journey in life. Filed notes were recorded and transcribed verbatim. We used the method of content, semantic and pragmatic analysis. RESULTS: We contacted 103 patients, 100 agreed to participate. Mean age was 47.5 ± 3.3, mean follow-up was 30.9 ± 2.7 years. Three fundamental concerns stood out: discomfort with self-image; low back pain with daily activities; and lack of spinal flexibility. 50% were engaged in continuous physical exercise, and only some referred limitations with load-bearing work. Patients commonly described negative memories of the conservative treatment, but positive memories of the surgical process. In general, there was a good adaptation to social life (occupation, social and family relationships). Two-thirds were married, and 65 women had offspring. A frequent concern was the excess of radiographs over the years, and three developed breast cancer. CONCLUSIONS: Factors such as dissatisfaction with self-image, low back pain, and spine stiffness were relevant to patients throughout their journeys. Despite this, the great majority were satisfied with the treatment received, which allowed them to lead an integrated life in society. LEVEL OF EVIDENCE: Level II.

Influence of smoking on patient-reported outcome measures (PROMs) in patients undergoing surgery for adult spinal deformity: a propensity score-matched analysis.

PURPOSE: The purpose of this study was to determine the isolated influence of smoking in patient-reported outcome measures (PROMs) for adult spinal deformity (ASD) surgery excluding known tobacco-related complications. METHODS: Retrospective analysis of a prospective multicenter ASD database. Patients operated on ASD with 2 year post-operative follow-up were included. Former smokers (non-active smokers) and patients developing mechanical or infectious complications were excluded. Changes of PROMs over time were analyzed using mixed models for repeated measures (MMRM). Propensity score matching (PSM) (1:1 ratio, caliper 0.10) was performed without replacement using optimum algorithm, tolerance ≤ 0.001, and estimated with 95% confidence interval (CI). PROMS in both groups were compared by paired t test or Wilcoxon signed-rank test. RESULTS: 692 out of 1246 surgical patients met our inclusion criteria. 153 smokers were matched with 153 non-smokers according to age, BMI, number of fused levels, and global tilt. After PSM both groups were homogeneous regarding baseline parameters, surgical data, and complications (mechanical complications and infection excluded). Smokers had worse baseline results for SRS-total, SRS-pain COMI-back, and ODI; smokers also showed worse 2-year outcomes for SRS-total, SRS-function, SRS-pain, SRS-self-image, and ODI. However, no differences between the two groups were found in the improvement from baseline to 2-year follow-up or in the timing of this improvement (MMRM). The proportion of patients reaching the minimal clinically important difference (MCID) after surgery was similar in the two groups, but the proportion of patients reaching patient acceptable symptom state (PASS) was significantly lower in smokers for SRS-Subtotal, SRS-function, and SRS-image. CONCLUSION: Even in the absence of smoking-related complications, smokers had worse PROMs at baseline and 2 years after surgery with less patients achieving PASS, but similar degrees on improvement compared to non-smokers. The proportion achieving MCID was also similar between the two cohorts.

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.

Current biomechanical theories on the etiopathogenesis of idiopathic scoliosis.

PURPOSE: There is great controversy about the etiologic origin of adolescent idiopathic scoliosis. Multiple theories have been suggested, including metabolic aspects, endocrine dysfunction, neurological central abnormalities, genetic predisposition and epigenetic factors involved in the development of scoliosis. However, there has always been speculations based on human biomechanical behavior. METHODS: In this article, we performed a literature review on the biomechanical traits of human posture, and the proposed theories that explain the special characteristics present in idiopathic scoliosis. RESULTS: The current theory on the etiopathogeneis of AIS suggests that dorsally directed shear loads acting on a preexisting axial plane rotation, in a posteriorly inclined sagittal plane of a growing patient, together with disc maturation, collagen quality at this phase of development and immaturity of proprioception, is the perfect scenario to spark rotational instability and create the three-dimensional deformity that defines idiopathic scoliosis. CONCLUSION: The unique spinal alignment of human bipedalism, gravity and muscle forces acting straight above the pelvis to preserve an upright balance, and the instability of the soft tissue in a period of growth development, is an appealing cocktail to try to explain the genesis of this condition in humans.

Adolescent Idiopathic Scoliosis: Is the Feasible Option of Minimally Invasive Surgery using Posterior Approach?

The purpose of this systematic review and meta-analysis is to perform a systematic review and meta-analysis of previous studies on minimally invasive scoliosis surgery (MISS) in adolescents with idiopathic scoliosis (AIS). Some data on MISS in AIS compared with conventional open scoliosis surgery (COSS) are conflicting. A systematic literature search was conducted in Medline, Embase, and Cochrane Library, including studies reporting outcomes for MISS in AIS. The meta-analysis compared the operative, radiological, and clinical outcomes and complications between MISS and COSS in patients with AIS. Of the 208 records identified, 15 nonrandomized studies with 1,369 patients (reviews and case reports are excluded) were included in this systematic review and meta-analysis. The mean scale was 6.1, and eight of the 15 included studies showed satisfactory quality using the Newcastle-Ottawa scale. For operative outcomes, MISS had significant benefits in terms of estimated blood loss (standard mean difference [SMD], -1.87; 95% confidence interval [CI], -2.94 to -0.91) and hospitalization days (SMD, -2.99; 95% CI, -4.45 to -1.53) compared with COSS. However, COSS showed significantly favorable outcomes for operative times (SMD, 1.71; 95% CI, 0.92-2.51). No significant differences were observed in radiological outcomes, including Cobb's angle of the main curve and thoracic kyphosis. For clinical outcomes, MISS showed significant benefits on the visual analog scale score (SMD, -0.91; 95% CI, -1.36 to -0.47). The overall complication rates of MISS were similar to those of COSS (SMD, 0.96; 95% CI, 0.61-1.52). MISS using the posterior approach provides equivalent radiological and clinical outcomes and complication rates compared with COSS. Considering the lower estimated blood loss, shorter hospitalization days, and longer operative times in MISS, COSS is still the mainstay of surgical treatment in AIS; however, MISS using the posterior approach is also one of the surgical options of choice in the case of moderate AIS.

Rotational Changes Following Use of Direct Vertebral Rotation in Adolescent Idiopathic Scoliosis: A Long-term Radiographic and Computed Tomography Evaluation.

STUDY DESIGN: A retrospective cohort study. OBJECTIVE: To evaluate long-term rotational changes in the vertebrae of patients with adolescent idiopathic scoliosis (AIS) who underwent direct vertebral rotation (DVR). SUMMARY OF BACKGROUND DATA: DVR using thoracic pedicle screws, a rotational corrective maneuver used in the surgical treatment of AIS, was introduced in 2004. Although DVR is considered to be the main axial corrective maneuver, the long-term rotational changes of vertebrae following this treatment are not well understood. METHODS: A total of 135 vertebrae that underwent DVR using thoracic pedicle screws with a minimum 5-year follow-up were retrospectively assessed for the vertebral rotation angle. Vertebral rotation of the apical vertebra (AV), and distal end vertebra (EV) was evaluated using the Nash-Moe scale, the rotational angle to the sacrum (RAsac), and the Aaro and Dahlborn method. Student's t-test (paired means) was used for continuous variables, and the chi-square test was used for categorical variables, as appropriate. A comparison of two and three groups used a one-way repeated measures analysis of variance, and the post hoc analysis used the Bonferroni test. RESULTS: The mean Nash-Moe scale of distal EV showed statistically significant differences between preoperative and postoperative values (P=0.034) and no statistically significant difference between postoperative and last follow-up values (P=1.000). The last follow-up RAsac of AV did not differ significantly from the preoperative RAsac of AV (P=0.515). The last follow-up RAsac of distal EV was significantly lower than the preoperative RAsac of distal EV (P=0.001). Pearson's correlation analysis showed that the last follow-up RAsac of distal EV was correlated with Cobb angle of the main curve (r=0.459, P=0.004), loss of correction (r=0.541, P=0.001), and LIV tilt angle (r=0.504, P=0.001). CONCLUSIONS: The rotation regression phenomenon in AV and rotation maintenance in distal EV were observed after DVR over an average of 10-year follow-up. These findings suggest that the DVR in the surgical treatment of AIS has a positive long-term effect on the stabilization of distal EV from the point of view of axial rotation. LEVEL OF EVIDENCE: IV.

La transición posquirúrgica en adolescentes que padecen escoliosis idiopática. Un estudio cualitativo / The post-surgical transition in adolescents who have idiopathic scoliosis. A qualitative study

Objetivo: Conocer el proceso que viven las y los adolescentes que padecen escoliosis idiopática al intervenirse quirúrgicamente para corregir la deformidad física. Método: Estudio cualitativo con enfoque interaccionismo simbólico. Se realizaron 22 entrevistas semiestructuradas a adolescentes intervenidos de fusión espinal posterior en un hospital de tercer nivel de Madrid entre mayo de 2019 y enero de 2021. Se llevó a cabo análisis en progreso de Taylor y Bogdan. Resultados: Los pacientes con escoliosis idiopática del adolescente presentan una transición compleja simultánea de tipo salud/enfermedad y de desarrollo. Las principales condiciones inhibidoras de la transición son los significados sobre: su identidad, sociales, creencias sobre la cirugía, el desconocimiento sobre la patología, el proceso quirúrgico y su recuperación. Como condiciones facilitadoras encontramos: la actitud positiva hacia el cambio físico, estético, social, el nivel socioeconómico y el apoyo familiar. Conclusiones: Los informantes de este estudio refieren que la afectación estética y las limitaciones físicas son los principales elementos que les causan disconfort. La intervención quirúrgica se presenta como la solución a esta situación. La recuperación es un punto crítico en el proceso de transición debido principalmente al dolor. Aceptan el malestar sufrido durante la recuperación porque esperan obtener una mejora en la imagen y las limitaciones físicas. Los cambios y diferencias que experimentan durante la transición les hace pensar que van a poder llevar una «vida normal» a la que se refieren constantemente en los discursos.(AU)

Objective: To know the process experienced by adolescents suffering from idiopathic scoliosis when undergoing surgery to correct the physical deformity. Method: Qualitative study with a symbolic interactionism approach. 22 semi-structured interviews were conducted with adolescents who underwent posterior spinal fusion in a third-level hospital in Madrid between May 2019 and January 2021. Taylor and Bogdan's analysis in progress was carried out. Results: Patients with adolescent idiopathic scoliosis present with a complex simultaneous health/illness and developmental transition. The main inhibitory conditions of the transition are the meanings about: their identity, social, beliefs about surgery, ignorance about the pathology, the surgical process, and their recovery. As facilitating conditions, we find: a positive attitude towards physical, aesthetic, and social change, socioeconomic level, and family support. Conclusions: The informants of this study refer that aesthetic affectation and physical limitations are the main elements that cause them discomfort. Surgical intervention is presented as the solution to this situation. Recovery is a critical point in the transition process mainly due to pain. They accept the discomfort suffered during the recovery because they hope to obtain an improvement in the image and physical limitations. The changes and differences they experience during the transition make them think that they will be able to lead a «normal life» to which they constantly refer in their speeches.(AU)