Spinal Deformity Research Articles

Use of Artificial Intelligence in Cobb Angle Measurement for Scoliosis: Retrospective Reliability and Accuracy Study of a Mobile App.

Scoliosis is a spinal deformity in which one or more spinal segments bend to the side or show vertebral rotation. Some artificial intelligence (AI) apps have already been developed for measuring the Cobb angle in patients with scoliosis. These apps still require doctors to perform certain measurements, which can lead to interobserver variability. The AI app (cobbAngle pro) in this study will eliminate the need for doctor measurements, achieving complete automation. We aimed to evaluate the reliability and accuracy of our new AI app that is based on deep learning to automatically measure the Cobb angle in patients with scoliosis. A retrospective analysis was conducted on the clinical data of children with scoliosis who were treated at the Pediatric Orthopedics Department of the Children's Hospital affiliated with Fudan University from July 2019 to July 2022. Three measurers used the Picture Archiving and Communication System (PACS) to measure the coronal main curve Cobb angle in 802 full-length anteroposterior and lateral spine X-rays of 601 children with scoliosis, and recorded the results of each measurement. After an interval of 2 weeks, the mobile AI app was used to remeasure the Cobb angle once. The Cobb angle measurements from the PACS were used as the reference standard, and the accuracy of the Cobb angle measurements by the app was analyzed through the Bland-Altman test. The intraclass correlation coefficient (ICC) was used to compare the repeatability within measurers and the consistency between measurers. Among 601 children with scoliosis, 89 were male and 512 were female (age range: 10-17 years), and 802 full-length spinal X-rays were analyzed. Two functionalities of the app (photography and photo upload) were compared with the PACS for measuring the Cobb angle. The consistency was found to be excellent. The average absolute errors of the Cobb angle measured by the photography and upload methods were 2.00 and 2.08, respectively. Using a clinical allowance maximum error of 5°, the 95% limits of agreement (LoAs) for Cobb angle measurements by the photography and upload methods were -4.7° to 4.9° and -4.9° to 4.9°, respectively. For the photography and upload methods, the 95% LoAs for measuring Cobb angles were -4.3° to 4.6° and -4.4° to 4.7°, respectively, in mild scoliosis patients; -4.9° to 5.2° and -5.1° to 5.1°, respectively, in moderate scoliosis patients; and -5.2° to 5.0° and -6.0° to 4.8°, respectively, in severe scoliosis patients. The Cobb angle measured by the 3 observers twice before and after using the photography method had good repeatability (P<.001). The consistency between the observers was excellent (P<.001). The new AI platform is accurate and repeatable in the automatic measurement of the Cobb angle of the main curvature in patients with scoliosis.

Risk factors for postoperative ileus after corrective spinal surgery: association with reduction in the retrocrural space area.

The objective of this study was to determine whether a reduction in the retrocrural space (RCS) area is a risk factor for postoperative ileus (POI) in patients with adult spinal deformity (ASD) treated with spinal corrective surgery. In total, 100 patients (mean age 67.5 ± 8.3 years, 9 males and 91 females) with ASD treated with spinal corrective surgery were included in this study. Spinal parameters, including thoracolumbar kyphosis (TLK), and RCS area were measured pre- and postoperatively. The change (Δ) in spinal parameters was calculated. The percent change between pre- and postoperative RCS areas was calculated as ΔRCS. Patients were identified as having POI if they exhibited both gastrointestinal symptoms and radiographic findings. Each parameter was compared between patients with and without POI. Multivariable logistic regression analysis was performed with development of POI as the dependent variable. The incidence of POI was 11.0%. The RCS area was significantly smaller in the POI group than in the non-POI group (p < 0.001). Multivariable logistic regression analysis revealed that ΔTLK and ΔRCS were risk factors for POI (p = 0.029 and p = 0.033, respectively). A reduction in the RCS area is a risk factor for the development of POI after corrective spinal surgery in patients with ASD. Overcorrection of the thoracolumbar junction should be avoided to prevent POI.

Frail patients require instrumentation of a more proximal vertebra for a successful outcome after surgery for adult spine deformity.

The aim of this study was to investigate the impact of the level of upper instrumented vertebra (UIV) in frail patients undergoing surgery for adult spine deformity (ASD). Patients with adult spinal deformity who had undergone T9-to-pelvis fusion were stratified using the ASD-Modified Frailty Index into not frail, frail, and severely frail categories. ASD was defined as at least one of: scoliosis ≥ 20°, sagittal vertical axis (SVA) ≥ 5 cm, or pelvic tilt ≥ 25°. Means comparisons tests were used to assess differences between both groups. Logistic regression analyses were used to analyze associations between frailty categories, UIV, and outcomes. A total of 477 patients were included (mean age 60.3 years (SD 14.9), mean BMI 27.5 kg/m2 (SD 5.8), mean Charlson Comorbidity Index (CCI) 1.67 (SD 1.66)). Overall, 74% of patients were female (n = 353), and 49.6% of patients were not frail (237), 35.4% frail (n = 169), and 15% severely frail (n = 71). At baseline, differences in age, BMI, CCI, and deformity were significant (all p = 0.001). Overall, 15.5% of patients (n = 74) had experienced mechanical complications by two years (8.1% not frail (n = 36), 15.1% frail (n = 26), and 16.3% severely frail (n = 12); p = 0.013). Reoperations also differed between groups (20.2% (n = 48) vs 23.3% (n = 39) vs 32.6% (n = 23); p = 0.011). Controlling for osteoporosis, baseline deformity, and degree of correction (by sagittal age-adjusted score (SAAS) matching), frail and severely frail patients were more likely to experience mechanical complications if they had heart failure (odds ratio (OR) 6.6 (95% CI 1.6 to 26.7); p = 0.008), depression (OR 5.1 (95% CI 1.1 to 25.7); p = 0.048), or cancer (OR 1.5 (95% CI 1.1 to 1.4); p = 0.004). Frail and severely frail patients experienced higher rates of mechanical complication than 'not frail' patients at two years (19% (n = 45) vs 11.9% (n = 29); p = 0.003). When controlling for baseline deformity and degree of correction in severely frail and frail patients, severely frail patients were less likely to experience clinically relevant proximal junctional kyphosis or failure or mechanical complications by two years, if they had a more proximal UIV. Frail patients are at risk of a poor outcome after surgery for adult spinal deformity due to their comorbidities. Although a definitively prescriptive upper instrumented vertebra remains elusive, these patients appear to be at greater risk for a poor outcome if the upper instrumented vertebra is sited more distally.

Characteristics of sagittal spinopelvic alignment in Thai population: a cross-sectional study.

The prevalence of spinal deformity is a significant health concern often associated with the aging process. It is primarily attributed to the thickening of spinal joints, ligament pathologies, or the narrowing of the spinal canal, leading to compression of the spinal cord and nerve roots, and subsequently causing musculoskeletal problems. When considering corrective surgery for adult spinal deformities, it is crucial for spine surgeons to take into account the standard values of sagittal spinopelvic alignment. Notably, there is currently a lack of specific data on this aspect within the Thai population. Therefore, our study was focused on evaluating the alignment in the Thai population. To analyze sagittal spinopelvic alignment parameters in the asymptomatic Thai population and compare them with other populations. This study was designed as a cross-sectional analysis involving 194 participants, wherein the sagittal spinopelvic parameters were evaluated utilizing radiographic images. The measurements of the sagittal vertical axis (SVA), pelvic incidence (PI), lumbar lordosis (LL), sacral slope (SS), and pelvic tilt (PT) were determined by averaging the assessments conducted by two orthopedic residents and a spine surgeon. In addition, participants' demographic information was obtained through questionnaires, and further analysis was performed on age, gender, and body mass index data. The study also encompassed the determination of correlations between various parameters and the comparison of these parameters with other populations. The body mass index (BMI) of the study participants demonstrated significant associations with several spinal parameters. Specifically, BMI showed significant correlations with sagittal vertical axis (SVA) (r = 0.2, p = 0.09), pelvic incidence (PI) (r = 0.4, p < 0.01), lumbar lordosis (LL) (r = 0.2, p = 0.02), sacral slope (SS) (r = -0.2, p = 0.02), and pelvic tilt (PT) (r = 0.2, p = 0.02). The SS exhibited a statistically significant decline with increasing age (p = 0.04). Furthermore, the mean SVA, PI, LL, SS, and PT differed significantly between the study participants and the Indian population. In addition, the SS was notably lower when compared to the European population. The study revealed the spinopelvic parameters in a cohort of healthy Thai population and observed a correlation between their body mass index (BMI) and pelvic incidence (PI), lumbar lordosis (LL), sacral slope (SS), and pelvic tilt (PT). Notably, the average SS among Thai adults was found to be statistically lower than that of individuals from Indian, European Caucasian, Asian, and Mexican populations. These insights hold potential value as a reference when strategizing surgical interventions for Thai patients with spinal deformities.

A Biomechanical Analysis of Instrumentation Constructs During Vertebral Column Resection: Stability When You Need It!

Biomechanical Testing. Investigate the optimal construct for stabilization of the spine during vertebral column resection (VCR). VCR is a powerful technique for achieving correction in severe cases of spinal deformity. However, this also creates an unstable spine which requires stable fixation to prevent iatrogenic neurologic injury. It is common practice to place a temporary unilateral rod configuration to achieve this stability during surgery but no study to date has investigated the optimal construct configuration. A unilateral VCR model representing an acute 50° kyphotic deformity with a standardized 30mm resection was created. Three conditions underwent testing: 1) Rod material and diameter, 2) rod configuration, and 3) number of fixation points. Six unique samples were tested in each group in both flexion-extension. Prior to testing a 10N preload and underwent cyclical testing in flexion/extension. System stiffness was calculated and compared across groups. Assessment of rod size and composition using a single screw construct (2 total screws) demonstrated that for Titanium (Ti) rods, increasing rod size significantly increased the construct stiffness (P=0.001). Although Cobalt-chromium (Co-Cr) rods where significantly stiffer than the corresponding sized Ti rods, there was no significant difference between rod diameters for Co-Cr (P=0.98). However, when tested using a dual screw (4 total screws) construct, these constructs were significantly stiffer than the corresponding single screw constructs (P<0.0001). Of the various rod configurations, the dual rod demonstrated the greatest stiffness (34.8±2.1N/mm; P<0.0001). Surgical construct stiffness during a VCR is multifactorial. Larger rod diameter, increased number of fixation points, stiffer rod material, and increased number of rods across the resection site increase the construct stiffness. With minimal points of fixation using Co-Cr rods, increasing rod diameter does not impart greater construct stiffness unless additional fixation points are included.

Literature review: Early-onset Scoliosis and the Space Available for Lung (SAL) post-surgery

Background: Early-onset scoliosis (EOS) poses significant risks to thoracic development and pulmonary function in children due to the deformities’ impact on the space available for lung (SAL). Various surgical techniques, including growth-sparing methods like growing rods, vertical expandable prosthetic titanium ribs (VEPTR), and the Shilla system, aim to correct spinal deformities while allowing for thoracic growth. This literature review explores the efficacy of these interventions in improving SAL and lung function, as measured by forced vital capacity (FVC) and other pulmonary outcomes. Studies indicate that growth-friendly techniques are associated with substantial improvements in SAL, with growing rods showing an average 30% increase in thoracic volume and a corresponding improvement in pulmonary function. VEPTR has been similarly effective in increasing thoracic volume by 25% in patients with thoracic insufficiency syndrome. The Shilla system offers advantages in maintaining spinal correction while promoting growth but has been noted for potential complications like metal debris. Conclusion: Despite these advances, complications such as hardware failure and the need for revision surgeries remain concerns. This review underscores the importance of early surgical intervention to maximize thoracic volume and prevent long-term pulmonary impairment. However, further research is needed to assess the long-term outcomes of these surgical techniques, particularly in adulthood.

Spine deformity surgery in patients with Beals syndrome can be effectively performed but does risk revision surgery.

Beals syndrome or congenital contractual arachnodactyly is a rare disorder characterized by multiple joint contractures, Marfanoid body habitus and crumpled ears and has been associated with scoliosis. This study reports a clinical series of patients with Beals syndrome who have had surgical treatment for their spinal deformity. A retrospective review of all patients at a single institution who had a genetically-confirmed diagnosis of Beals syndrome and had surgical treatment for their scoliosis were reviewed for surgical outcome and complications. There were eight patients who had surgery at an average age of 11.5years, four were female and four had cardiovascular abnormalities requiring treatment. The preoperative coronal Cobb was 82.3° which improved to 42.1°(46.8% correction), and 46.5° (43.5% correction) at final follow-up. Preoperative halo-gravity-traction was used in three patients. Three patients had a posterior instrumentation and fusion (PSFI), 2 a combined anterior/PSFI, 1 had tethering, 1 with PSFI with posteriorly-approached discectomy, and 1 with a PSFI and vertebral column resection. One of the eight patients had a critical intraoperative neuromonitoring event but was normal following appropriate responses and no patient awoke with neurologic deficits. Two had an unplanned return to the operating room for implant dislodgement and each had a successful revision. Scoliosis associated with Beals syndrome can have large curves at the time of surgery and require a variety of surgical approaches to achieve a good result. Revision surgery with return to the operating room is necessary in 25% of patients.

Influence of implant density on mechanical complications in adult spinal deformity surgery.

The purpose was to analyze how rod characteristics, screw density and cages influence the incidence of mechanical complications compared to patient-related factors and alignment in adult spinal deformity instrumented T9-T11 to pelvis. Register data of 302 patients was analyzed. Relative lumbar lordosis (RLL) and relative sagittal alignment (RSA) was measured. Surgical data included rod characteristics, pedicle screw density and interbody cages. Univariate and multivariate logistic regression models were used. Pseudarthrosis occurred in 24.1%. On univariate analysis Odds Ratio (OR) was 0.74 for ≥ 3 cages (p = 0.452), 0.48 for 4 rods (p = 0.008), 4.30 for high screw density (p = 0.001). Patient-related factors were non-significant. Multivariate OR was 0.59 for 4 rods (p = 0.084) and 4.67 for high screw density (p = 0.005). PJK/PJF occurred in 19.2%. Age > 60 had an OR 2.83 (p = 0.023), postoperative RSA malaligned OR 2.84 (p = 0.030), severely malaligned OR 6.54 (p < 0.001). Implant characteristics were non-significant. Multivariate OR was 1.26 for age > 60 (p = 0.657), 2.32 for malaligned RSA (p = 0.097), 5.69 for severely malaligned RSA (p = 0.001). Screw loosening occurred in 8.9%. Univariate OR was 0.95 for ≥ 3 cages (p = 0.920), 1.64 for 4 rods (p = 0.235), 0.25 for high screw density 1.5-2 (p = 0.011). Patient-related factors were non-significant. Multivariate OR for high screw density was 0.23 (p = 0.022). Four rods decrease the pseudarthrosis risk. Cages have a secondary role. High screw density doesn't prevent from pseudarthrosis. Postoperative malalignment is the main PJK/PJF risk factor. Age plays a secondary role. Implant characteristics have a minor influence. High screw density constructs have a lower risk for screw loosening. 3-Retrospective register study.

Stigma assessment scale for adolescent idiopathic scoliosis: A new tool for spine deformity stigma evaluation.

Stigma is the negative attitudes towards an illness or difference. The literature lacks detailed scales specifically addressing stigmatization in AIS. This study aimed to develop Adolescent Idiopathic Scoliosis Stigma Assessment Scale (AIS-SAS) to measure stigmatization in AIS patients. In creating the AIS-SAS, we developed items via literature review and expert input, confirmed content validity, and conducted a field test for construct validity and reliability. Our experts designed 38 items in three subscales: Scoliosis, Brace, and Surgery-related stigma. Exploratory factor analysis (EFA) and convergent validity were examined for construct validity. The convergent validity of AIS-SAS was assessed through its correlations with the Rosenberg Self-Esteem Scale (RSES), SRS-22, and Spinal Appearance Questionnaire (SAQ). Reliability was gauged via internal consistency and test-retest methods. Sixty-seven adolescents with AIS were included in the study. EFA results confirmed one-dimensionality for each subscale, with factor loadings from 0.51 to 0.96, leading to the removal of 8 items with loadings below 0.3 from the AIS-SAS. The final AIS-SAS has three subscales: scoliosis (18 items), brace (5 items), and surgery-related stigma (7 items). Regarding convergent validity, the scoliosis-related stigma scores significantly correlated with SRS-22 self-image (r= -0.413 p = 0.001) and SAQ-Appearance (r = 0.441 p = 0.002). The RSES-Total score shows a negative correlation with Scoliosis, Brace, and Surgery-related stigma scores: -0.500 (p < 0.001), -0.435 (p = 0.049), and -0.498 (p = 0.042), respectively. AIS-SAS subscales showed good reliability (Cronbach-α > 0.8 ICC > 0.8). AIS-SAS is the first valid and reliable high-quality scale assessing stigmatization from AIS, measuring scoliosis, brace, and surgery-related stigma via three subscales.

Enhanced Safety and Efficacy of O-Arm Navigation Over C-Arm Guidance in Percutaneous Kyphoplasty for Patients With Osteoporotic Vertebral Compression Fractures and Spinal Deformity: A Comparative Study.

Although percutaneous kyphoplasty (PKP) under C-arm guidance is an effective treatment for osteoporotic vertebral compression fractures (OVCF), obtaining high-definition images in patients with OVCF and spinal deformities can be challenging or insufficient using traditional C-arm guidance, prompting our institution to adopt the O-arm navigation system-which offers comprehensive 3D imaging and precise navigation-and this study compares its safety and efficacy with conventional C-arm-assisted PKP. This was a retrospective study. From February 2019 to February 2022, we enrolled 28 patients with OVCF (44 vertebrae) with spinal deformity treated with O-arm navigation-assisted PKP and 30 patients with OVCF (42 vertebrae) with spinal deformity treated with C-arm-guided PKP. We recorded puncture times, single-segment operation time, number of cases with bone cement leakage, and length of stay. The visual analog scales (VASs), Oswestry disability indexes (ODIs), recovery of Cobbs angle, and vertebral height were used to assess treatment effect before the operation, on the first day postoperation, the first month postoperation, and at the final follow-up. The chi-squared test was utilized for comparing discrete variables, an independent samples t-test was used for continuous variables, and Pearson's chi-squared test and Fisher's exact test were applied for categorical data. Demographic features were comparable between the groups. The O-arm navigation group showed a significant reduction in puncture adjustment per vertebrae, single-segment operation time, and the rate of trocar needle malposition compared to the C-arm guidance group. The rate of cement leakage was decreased in the O-arm-guided PKP group, and other complications did not differ between the two groups. Intragroup comparisons revealed significant improvements in VAS scores and ODI on the first day, first month, and final follow-up after the operation (p < 0.05). The VAS score was significantly lower in the O-arm navigation-assisted PKP group than in the C-arm-guided PKP group on the first day postoperatively (p = 0.049). However, no significant differences in VAS scores were observed between the groups at the first month postoperatively or at the final follow-up. In each follow-up period, there was no significant difference in ODI, Cobb angle, and the percent of anterior vertebral height (AVH %) between the groups. O-arm navigation-assisted PKP demonstrates better clinical safety and efficacy than C-arm-guided PKP, marking it as a minimally invasive, safe, and effective procedure for treating patients with OVCF with spinal deformity.

GROWTH-FRIENDLY SPINAL SURGERY: REVIEW OF THE EFFECT ON TRUNCAL GROWTH

BackgroundPediatric spinal deformity surgery affects ultimate spinal height in the growing child. This effect on ultimate spinal height has also been shown to affect pulmonary development and ultimately pulmonary function. There has been an increasing trend toward growth-friendly spinal surgery in early onset scoliosis to minimize the negative consequences of early spinal fusion surgery. Such growth-friendly techniques include VEPTR, MCGR, and Shilla. Which technique allows for the most growth after initial implantation is still not clear. MethodsAn extensive literature review on the topic of pediatric spinal growth was undertaken. Topics reviewed include: normal growth, growth after intervention by various methods, and the effect on pulmonary function. We have summarized the literature for the techniques identified and compared these with normal population data.. ResultsThe data for various surgical techniques were reviewed. These included VEPTR, standard growing rods, and MCGR. The measurement techniques for determining ultimate spinal growth varied based upon the technique for measurement and the timing of initial and final measurements. The results of attained spinal growth were not directly correlated to pulmonary function values. ConclusionsThere is still no standardized ideal time or technique for assessing the best results in this area. We suggest that some of what is called growth from growth-friendly techniques is lengthening from the initial deformity correction. This nomenclature needs to be clarified. In addition, how and when to determine ultimate spinal growth from each surgical technique and by which radiographic technique needs to be standardized.

Development of the scoliosis research society spinal deformity surgery safety checklist.

Spine deformity surgery is a complex multi-step procedure that has a relatively high complication rate. The use of surgical safety checklists has been shown to reduce perioperative adverse events, but existing lists are varied and non-specific for spinal deformity surgery. Thus, the purpose of this study was to develop a comprehensive surgical checklist for complex spinal corrective surgery. An electronic survey consisting of 187 surgical checklist items that had been developed and used by a group of SRS members over a 5-year period was distributed to the Scoliosis Research Society Safety and Value Committee membership. The survey sections included: (1) pre-operative area, (2) initial operating room visit, (3) before turning, (4) positioning, (5) prepare and drape, (6) pre-incision timeout, (7) intraoperative, (8) finishing implant placement and confirming imaging, (9) final rods and locking, (10) prior to closure, (11) closure, (12) turn to supine, and (13) checkout/debriefing. Respondents graded each item on a five-point Likert scale based on their perceived importance and feasibility for inclusion in the checklist. Features graded as "moderately important" or "very important" to include by at least 70% of respondents were considered to meet the cutoff for inclusion-based standard Delphi practices. Study data were collated using REDCap. A total of 25 surgeons completed the survey in its entirety. The overall checklist "package" was shortened to 9 individual checklist modules, with 2 to 16 items per checklist. In terms of individual checklist items, 40% of items (74 of 187) met the cutoff for inclusion; 17 of these items were graded as "very important," which included verifying the presence of implantable devices, reviewing the surgical plan and positioning with the surgical staff, securing the endotracheal tube, bite block confirmation, prone and lateral positioning, neuromonitoring baseline readings, double-checking that the implant screw caps were locked prior to closure, and confirming that the patient was moving bilateral lower extremities before leaving the operating room when possible. This study has led to the development of a specific spinal deformity surgical checklist of 74 (many specific to spine surgery) items that were considered important for inclusion; 17 were considered "very important".

Intra-operative neuromonitoring in paediatric spinal deformity surgery: a retrospective single-centre experience.

Intra-operative neuromonitoring including somatosensory evoked potentials, motor evoked potentials, and electromyography, have replaced the Stagnara wake-up test to allow early detection of neurological change during paediatric spinal deformity surgery. It is important for surgeons to recognize alerts triggered by loss of these potentials and act accordingly to prevent iatrogenic neurological damage intra-operatively. This study was conducted to determine the sensitivity and specificity of neuromonitoring alerts in paediatric spinal deformity correction surgery. A retrospective single-centre study of all patients undergoing spinal deformity surgery at a tertiary paediatric centre between 1 January 2017 and 31 December 2020 (inclusive) was conducted. Neuromonitoring alerts were identified through neurophysiology documentation, and these were correlated with neurological deficits documented in the patient record post-operatively. A total of 399 operations were included in the study, with 147 (35.7%) of these having a motor, or motor and sensory alert triggered. Fifteen (10.2% of alerts) of these patients had a post-operative neurological deficit, compared to seven (2.8% of no alerts) of those that had no neuromonitoring alert. The sensitivity for post-operative neurological deficits not resolving within 3 days was 100%, and the specificity was 65.5%. Intra-operative neuromonitoring is highly sensitive to post-operative neurological deficits lasting longer than 3 days. However, there is still scope for optimization of specificity, with many false positives identified.

Anatomical landmark detection on bi-planar radiographs for predicting spinopelvic parameters.

Accurate landmark detection is essential for precise analysis of anatomical structures, supporting diagnosis, treatment planning, and monitoring in patients with spinal deformities. Conventional methods rely on laborious landmark identification by medical experts, which motivates automation. The proposed deep learning pipeline processes bi-planar radiographs to determine spinopelvic parameters and Cobb angles without manual supervision. The dataset used for training and evaluation consisted of 555 bi-planar radiographs from un-instrumented patients, which were manually annotated by medical professionals. The pipeline performed a pre-processing step to determine regions of interest, including the cervical spine, thoracolumbar spine, sacrum, and pelvis. For each ROI, a segmentation network was trained to identify vertebral bodies and pelvic landmarks. The U-Net architecture was trained on 455 bi-planar radiographs using binary cross-entropy loss. The post-processing algorithm determined spinal alignment and angular parameters based on the segmentation output. We evaluated the pipeline on a test set of 100 previously unseen bi-planar radiographs, using the mean absolute difference between annotated and predicted landmarks as the performance metric. The spinopelvic parameter predictions of the pipeline were compared to the measurements of two experienced medical professionals using intraclass correlation coefficient(ICC) and mean absolute deviation (MAD). The pipeline was able to successfully predict the Cobb angles in 61% of all test cases and achieved mean absolute differences of 3.3° (3.6°) and averaged ICC of 0.88. For thoracic kyphosis, lumbar lordosis, sagittal vertical axis, sacral slope, pelvic tilt, and pelvic incidence, the pipeline produced reasonable outputs in 69%, 58%, 86%, 85%, 84%, and 84% of the cases. The MAD was 5.6° (7.8°), 4.7° (4.3°), 2.8mm (3.0mm), 4.5° (7.2°), 1.8° (1.8°), and 5.3° (7.7°), while the ICC was measured at 0.69, 0.82, 0.99, 0.61, 0.96, and 0.70, respectively. Despite limitations in patients with severe pathologies and high BMI, the pipeline automatically predicted coronal and sagittal spinopelvic parameters, which has the potential to simplify clinical routines and large-scale retrospective data analysis.

Defining modern iatrogenic flatback syndrome: examination of segmental lordosis in short lumbar fusion patients undergoing thoracolumbar deformity correction.

Understanding the mechanism and extent of preoperative deformity in revision procedures may provide data to prevent future failures in lumbar spinal fusion patients. ASD patients without prior spine surgery (PRIMARY) and with prior short (SHORT) and long (LONG) fusions were included. SHORT patients were stratified into modes of failure: implant, junctional, malalignment, and neurologic. Baseline demographics, spinopelvic alignment, offset from alignment targets, and patient-reported outcome measures (PROMs) were compared across PRIMARY and SHORT cohorts. Segmental lordosis analyses, assessing under-, match, or over-correction to segmental and global lordosis targets, were performed by SRS-Schwab coronal curve type and construct length. Among 785 patients, 430 (55%) were PRIMARY and 355 (45%) were revisions. Revision procedures included 181 (23%) LONG and 174 (22%) SHORT corrections. SHORT modes of failure included 27% implant, 40% junctional, 73% malalignment, and/or 28% neurologic. SHORT patients were older, frailer, and had worse baseline deformity (PT, PI-LL, SVA) and PROMs (NRS, ODI, VR-12, SRS-22) compared to primary patients (p < 0.001). Segmental lordosis analysis identified 93%, 88%, and 62% undercorrected patients at LL, L1-L4, and L4-S1, respectively. SHORT patients more often underwent 3-column osteotomies (30% vs. 12%, p < 0.001) and had higher ISSG Surgical Invasiveness Score (87.8 vs. 78.3, p = 0.006). Nearly half of adult spinal deformity surgeries were revision fusions. Revision short fusions were associated with sagittal malalignment, often due to undercorrection of segmental lordosis goals, and frequently required more invasive procedures. Further initiatives to optimize alignment in lumbar fusions are needed to avoid costly and invasive deformity corrections. IV: Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding.

Unsupervised Clustering of Adult Spinal Deformity Patterns Predicts Surgical and Patient-Reported Outcomes.

Retrospective cohort study. To evaluate whether different radiographic clusters of adult spinal deformity identified using artificial intelligence-based clustering are associated with distinct surgical outcomes. Patients were classified based on the results of a previously conducted analysis that examined clusters of deformity, including Moderate Sagittal (Mod Sag), Severe Sagittal (Sev Sag), Coronal, and Hyper-Thoracic Kyphosis (Hyper-TK). The surgical data, HRQOL, and complication outcomes of these clusters were then compared. The final analysis included 1062 patients. Similar to published results on a different patient sample, Mod Sag and Sev Sag patients were older, more likely to have a history of previous spine surgery, and more disabled. By 2-year, all clusters improved in HRQOL and reached a similar rate of minimal clinically important difference (MCID).The Sev Sag cluster had the highest rate major complications (53% vs 34-40%), and complications leading to reoperation (29% vs 17-23%), implant failures (20% vs 8-11%), and operative complications (27% vs 10-17%). Coronal patients had the highest rate of pulmonary complications (9% vs 3-6%) but the lowest rate of X-ray imbalance (10% vs 19-21%). No significant differences were found in neurological complications, infection rate, gastrointestinal, or cardiac events (all P > .1). Kaplan-Meier survival curves demonstrated a lower time to first complications for the Sev Sag cluster. All clusters of adult spinal deformity benefit similarly from surgery as they all achieved similar rates of MCID. Although the rates of complications varied among the clusters, the types of complications were not significantly different.

A M-PEEK rod system to stabilize spinal motion after graded facetectomy: a finite element study

BackgroundResecting the facet joint to relieve nerve pain can lead to spinal instability, deformity, and abnormal pressure on the anterior of the intravertebral disc. To mitigate these issues, surgeons often limit the amount of bone removed during facetectomy or stabilize the spine by fusion to maintain lumbar stability. This study aimed to assess how a M-PEEK rod system influenced the stability of the lumbar spine during graded facetectomy.MethodsFacetectomy was performed on a validated L1-L5 finite element model which was then simulated both with and without the M-PEEK rod system.ResultsIn extension, models implanted with M-PEEK in the interspinous space of L3/L4 experienced a 35.2% decrease in range of motion (ROM) at L3/L4, while others saw an 8.4–24.8% increase. For axial rotation, the ROM at L3/L4 increased by 2.2–5.4% in models with the M-Rod, and by 4.9–12.9% in models without the implant. In lateral flexion, the ROM at L3/L4 increased by 8.4–14.3% in models without a PEEK M-Rod (facetectomy only), with adjacent segments experiencing a 6.5% decrease in ROM in the implanted models. Overall, the difference in ROM between the intact and implanted models was minimal.ConclusionsFacetectomy involving the removal of 50% or more of the facet joint significantly increases range of motion and maximum intradiscal pressure, potentially accelerating disc degeneration, as shown in our finite element study. Stabilizing the segment with an M-PEEK rod may limit excessive motion, providing stability and maintaining intradiscal pressure closer to that of an intact model.

Comparative advantages of activities with lumbosacral preservation for adult spinal deformity surgery: a retrospective Japanese cohort study.

Retrospective cohort study. This study aimed to demonstrate the advantages of preservation of the lumbosacral segment (LSS) in adult spinal deformity (ASD) surgery. Sacroiliac foundation enables sufficient restoration in ASD surgery; however, it could result in poor mobility. Thus, whether LSS provides better activities is still unknown. Among 399 patients who underwent ASD surgery, 62 (≥5 levels fused, >2-year follow-up) underwent fusion from T9-10 to L5 (group L, n=21) or to S2-alar-iliac (group S, n=41). Spinal alignments, Scoliosis Research Society (SRS)-22 scores, performance of activities (clipping toenail, wiping buttock, and wearing socks), proximal and distal junctional failure (PJF+DJF), rod fractures (RFs), and overall revision rates (RRs) were compared between the groups. Group L included younger patients and had longer follow-ups when compared with group S. Although the preoperative pelvic incidence and SRS sagittal modifiers were better in group L, postoperative spinal restorations were nonpathological in both groups. Both groups showed similar deformity progression at the 2-year follow-up; however, group L had lower SRS-22 pain scores. Although "wiping buttocks" did not differ between the groups, the performance of "clipping toenails" and "wearing socks" was poorer in group S at 2 years (possible, group S; 40% vs. group L; 85%-90%). The RRs did not differ between the groups; however, the PJF+DJF rate was higher in group L. DJF was not observed in group S, but occurrence of RFs was noted. Although poorer SRS-22 pain scores might be related to lumbosacral mobility, sufficient restoration, equivalent deformity progression, and similar RRs with better activity imply that lumbosacral preservation should be considered in younger patients with moderate deformities.

Hounsfield units and vertebral bone quality score for predicting mechanical complications after adult spinal deformity surgery: a systematic review and meta-analysis.

The purpose of this systematic review and meta-analysis is to assess existing literature and determine the association between the Hounsfield unit (HU) value and the vertebral body quality (VBQ) score with mechanical complications (MCs) after adult spinal deformity (ASD) surgery. Although bone quality is considered an increasingly important factor for MCs after ASD surgery, the utility of the HU value assessed by computed tomography and the VBQ score assessed by magnetic resonance imaging remains unknown. A systematic review of PubMed, Embase, and Cochrane Library databases was performed to find studies evaluating the association between the HU value and the VBQ score with MCs after ASD surgery. In the subsequent meta-analysis, MC outcomes were combined using a random-effects model, and the standardized mean difference and 95% confidence interval were calculated. The final analysis included a total of 20 studies. Nineteen studies reported HU values, and two studies reported VBQ scores. Proximal junctional kyphosis/failure (PJK/PJF) was reported as the MC in 16 studies, whereas other MCs were included in 6 studies. Six studies with a pool of 506 patients with ASD revealed that preoperative HU values at the upper instrumented vertebra (UIV) and UIV+1 were significantly lower in patients with PJK/PJF (standardized mean difference, -0.74; 95% confidence interval, -1.09 to -0.40). Three studies suggested an cutoff HU value of approximately ≤120, yielding a pooled sensitivity of 0.77, specificity of 0.67, and diagnostic odds ratio of 7.01. However, two studies reported conflicting results on the relationship between the VBQ score and PJK/PJF. Low HU values predicted the risk of certain MCs, particularly PJK/PJF, after ASD surgery. An HU value of <120 should alert surgeons to be cautious about the postoperative occurrence of PJK/PJF. Future studies are needed to validate the cutoff HU value and evaluate the utility of the VBQ score.

Determining the utility of three-column osteotomies in revision surgery compared with primary surgeries in the thoracolumbar spine: a retrospective cohort study in the United States.

Retrospective cohort study. To determine the incidence and success of three-column osteotomies (3COs) performed in primary and revision adult spine deformity (ASD) corrective surgeries. 3COs are often required to correct severe, rigid ASD presentations. However, controversy remains on the utility of 3COs, particularly in primary surgery. Patients ASD having 2-year data were included and divided into 3CO and non-3CO (remaining ASD cohort) groups. For the subanalysis, patients were stratified based on whether they were undergoing primary (P3CO) or revision (R3CO) surgery. Multivariate analysis controlling for age, Charlson comorbidity index, body mass index, baseline pelvic incidence-lumbar lordosis, and fused levels evaluated the complication rates and radiographic and patient-reported outcomes between the 3CO and non-3CO groups. Of the 436 patients included, 20% had 3COs. 3COs were performed in 16% of P3COs and 51% of R3COs. Both 3CO groups had greater severity in deformity and disability at baseline; however, only R3COs improved more than non-3COs. Despite greater segmental correction, 3COs had much lower rates of aligning in the lumbar distribution index (LDI), higher mechanical complications, and more reoperations when performed below L3. When comparing P3COs and R3COs, baseline lumbopelvic and global alignments, as well as disability, were different. The R3CO group had greater clinical improvements and global correction (both p<0.04), although the P3CO group achieved alignment in LDI more often (odds ratio, 3.9; 95% confidence interval, 1.3-6.2; p=0.006). The P3CO group had more neurological complications (30% vs. 13%, p=0.042), whereas the R3CO tended to have higher mechanical complication rates (25% vs. 15%, p=0.2). 3COs showed greater improvements in realignment while failing to demonstrate the same clinical improvement as primaries without a 3CO. Overall, when suitably indicated, a 3CO offers superior utility for achieving optimal realignment across primary and revision surgeries for ASD correction.