The artificial intelligence (AI) revolution is underway. AI has become omnipresent in medicine, and its broad capabilities have permitted significant developments in many subspecialties including spine surgery. With AI, spine surgeons have been able to perform advanced computational analytics on vast amounts of data, allowing for solutions in each step of patient care from preoperative evaluation and planning, intraoperative execution, and postoperative evaluation. The tremendous potential of AI in medicine is clear and exciting. However, as the utility of AI in clinical practice expands, the medicolegal implications of this technology are poorly understood. In this chapter, we explore the existing technology, ethical considerations, legal challenges, and risk management strategies as it relates to AI in the field of spine surgery.

Early onset scoliosis (EOS) patient diversity makes outcome prediction challenging. Machine learning offers an innovative approach to analyze patient data and predict results, including LOS in pediatric spinal deformity surgery. Children under 10 with EOS were chosen from the American College of Surgeon’s NSQIP database. Extended LOS, defined as over 5 days, was predicted using feature selection and machine learning in Python. The best model, determined by the area under the curve (AUC), was optimized and used to create a risk calculator for prolonged LOS. The study included 1587 patients, mostly young (average age: 6.94 ± 2.58 years), with 33.1

Spinal deformity surgery often requires complex surgical interventions that can have a drastic effect on both patient quality of life and functional capacity. Modern-day corrective solutions for these deformities include spinal osteotomies, pedicle screw instrumentation, and dual/multirod constructs. These solutions are efficacious and are currently considered standard practice for spinal surgeons, but they lack individualization. Patient-specific rods (PSRs) are a novel technology that attempts to offer a personalized approach to spinal deformity correction based on preoperative computerized tomography scans. Moreover, PSRs may offer several advantages to conventional rods, which include achievement of desired rod contour angles according to surgical planning alignment goals, reduced operative time, and reduced blood loss. In adolescent idiopathic scoliosis, those instrumented with PSR have observed coronal Cobb reductions up to 74%. In adult spinal deformity, PSRs have offered superior correction in radiographic parameters such as sagittal vertical axis and pelvic incidence minus lumbar lordosis. However, there still remains a paucity of research in this area, mainly in health care expenditure, cost-effectiveness, and longitudinal clinical outcomes. The purpose of this article is to survey the current body of knowledge of PSR instrumentation in both adolescent and adult spinal deformity populations. The current strength, limitations, and future directions of PSRs are highlighted throughout this article.

Background: The Internet is an important source of information for patients, but its effectiveness relies on the readability of its content. Patient education materials (PEMs) should be written at or below a sixthgrade reading level as outlined by agencies such as the American Medical Association. This study assessed PEMs' readability for the novel anterior vertebral body tethering (AVBT), distraction - based methods, and posterior spinal fusion (PSF) in treating pediatric spinal deformity. Methods: An online search identified PEMs using the terms "anterior vertebral body tethering," "growing rods scoliosis," and "posterior spinal fusion pediatric scoliosis." We selected the first 20 general medical websites (GMWs) and 10 academic health institution websites (AHIWs) discussing each treatment (90 websites total). Readability tests for each webpage were conducted using Readability Studio software. Reading grade levels (RGLs), which correspond to the US grade at which one is expected to comprehend the text, were calculated for sources and independent t tests compared with RGLs between treatment types. Results: The mean RGL was 12.1 +/- 2.0. No articles were below a sixthgrade reading level, with only 2.2% at the sixthgrade reading level. AVBT articles had a higher RGL than distraction - based methods (12.7 +/- 1.6 vs 11.9 +/- 1.9, P = 0.082) and PSF (12.7 +/- 1.6 vs 11.6 +/- 2.3, P = 0.032). Materials for distraction - based methods and PSF were comparable (11.9 +/- 1.9 vs 11.6 +/- 2.3, P = 0.566). Among GMWs, AVBT materials had a higher RGL than distraction - based methods (12.9 +/- 1.4 vs 12.1 +/- 1.8, P = 0.133) and PSF (12.9 +/- 1.4 vs 11.4 +/- 2.4, P = 0.016). Clinical Relevance: Patients' health literacy is important for shared decision- making. Assessing the readability of scoliosis treatment PEMs guides physicians when sharing resources and discussing treatment with patients. Conclusion: Both GMWs and AHIWs exceed recommended RGLs, which may limit patient and parent understanding. Within GMWs, AVBT materials are written at a higher RGL than other treatments, which may hinder informed decision- making and patient outcomes. Efforts should be made to create online resources at the appropriate RGL. At the very least, patients and parents may be directed toward AHIWs; RGLs are more consistent. Level of Evidence: 3.

New evidence highlights the significance of 3D in-brace correction for Adolescent Idiopathic Scoliosis (AIS) patients. This study explores how axial parameters relate to treatment failure in braced AIS patients. AIS patients (Sanders 1–5) undergoing Rigo-Chêneau bracing at a single institution were included. Axial vertebral rotation (AVR) was determined by utilizing pre-brace and in-brace 3D reconstructions from EOS® radiographs. The primary outcome was treatment failure: surgery or coronal curve progression > 5°. Minimum follow-up was two years. 75 patients (81

BACKGROUND:An accurate knowledge of a patient's risk of cord-level intraoperative neuromonitoring (IONM) data loss is important for an informed decision-making process prior to deformity correction, but no prediction tool currently exists. METHODS:A total of 1,106 patients with spinal deformity and 205 perioperative variables were included. A stepwise machine-learning (ML) approach using random forest (RF) analysis and multivariable logistic regression was performed. Patients were randomly allocated to training (75% of patients) and testing (25% of patients) groups. Feature score weights were derived by rounding up the regression coefficients from the multivariable logistic regression model. Variables in the final scoring calculator were automatically selected through the ML process to optimize predictive performance. RESULTS:Eight features were included in the scoring system: sagittal deformity angular ratio (sDAR) of ≥15 (score = 2), type-3 spinal cord shape (score = 2), conus level below L2 (score = 2), cervical upper instrumented vertebra (score = 2), preoperative upright largest thoracic Cobb angle of ≥75° (score = 2), preoperative lower-extremity motor deficit (score = 2), preoperative upright largest thoracic kyphosis of ≥80° (score = 1), and total deformity angular ratio (tDAR) of ≥25 (score = 1). Higher cumulative scores were associated with increased rates of cord-level IONM data loss: patients with a cumulative score of ≤2 had a cord-level IONM data loss rate of 0.9%, whereas those with a score of ≥7 had a loss rate of 86%. When evaluated in the testing group, the scoring system achieved an accuracy of 93%, a sensitivity of 75%, a specificity of 94%, and an AUC (area under the receiver operating characteristic curve) of 0.898. CONCLUSIONS:This is the first study to provide an ML-derived preoperative scoring system that predicts cord-level IONM data loss during pediatric and adult spinal deformity surgery with >90% accuracy. LEVEL OF EVIDENCE:Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

To determine if an improvement in cord-level intraoperative neuromonitoring (IONM) data following data loss results in a reduced risk for new postoperative motor deficit in pediatric and adult spinal deformity surgery. A consecutive series of 1106 patients underwent spine surgery from 2015 to 2023 by a single surgeon. Cord alerts were defined by Somatosensory-Evoked Potentials (SSEP; warning criteria: 10

OBJECTIVE:The objective was to describe an intraoperative method that accurately predicts postoperative coronal alignment for up to 2 years of follow-up. The authors hypothesized that the intraoperative coronal target for adult spinal deformity (ASD) surgery should account for lower-extremity parameters, including pelvic obliquity (PO), leg length discrepancy (LLD), lower-extremity mechanical axis difference (MAD), and asymmetrical knee bending. METHODS:Two lines were drawn on intraoperative prone radiographs: the central sacral pelvic line (CSPL) (the line bisecting the sacrum and perpendicular to the line touching the acetabular sourcil of both hips) and the intraoperative central sacral vertical line (iCSVL) (which is drawn relative to CSPL based on the preoperative erect PO). The distance from the C7 spinous process to CSPL (C7-CSPL) and the distance from the C7 spinous process to iCSVL (iCVA) were compared with immediate and 2-year postoperative CVA. To account for LLD and preoperative lower-extremity compensation, patients were categorized into four preoperative groups: type 1, no LLD (< 1 cm) and no lower-extremity compensation; type 2, no LLD with lower-extremity compensation (PO > 1°, asymmetrical knee bending, and MAD > 2°); type 3, LLD and no lower-extremity compensation; and type 4, LLD with lower-extremity compensation (asymmetrical knee bending and MAD > 4°). A retrospective review of a consecutively collected cohort with ASD who underwent minimum 6-level fusion with pelvic fixation was performed for validation. RESULTS:In total, 108 patients (mean ± SD age 57.7 ± 13.7 years, 14.0 ± 3.9 levels fused) were reviewed. Mean preoperative/2-year postoperative CVA was 5.0 ± 2.0/2.2 ± 1.8 cm. For patients with type 1, both C7-CSPL and iCVA had similar error margins for immediate postoperative CVA (0.5 ± 0.6 vs 0.5 ± 0.6 cm, p = 0.900) and 2-year postoperative CVA (0.3 ± 0.4 vs 0.4 ± 0.5 cm, p = 0.185). For patients with type 2, C7-CSPL was more accurate for immediate postoperative CVA (0.8 ± 1.2 vs 1.7 ± 1.8 cm, p = 0.006) and 2-year postoperative CVA (0.7 ± 1.1 vs 2.1 ± 2.2 cm, p < 0.001). For patients with type 3, iCVA was more accurate for immediate postoperative CVA (0.3 ± 0.4 vs 1.7 ± 0.8 cm, p < 0.001) and 2-year postoperative CVA (0.3 ± 0.2 vs 1.9 ± 0.8 cm, p < 0.001). For patients with type 4, iCVA was more accurate for immediate postoperative CVA (0.6 ± 0.7 vs 3.0 ± 1.3 cm, p < 0.001) and 2-year postoperative CVA (0.5 ± 0.6 vs 3.0 ± 1.6 cm, p < 0.001). CONCLUSIONS:This system, which accounted for lower-extremity factors, provided an intraoperative guide to determine both immediate and 2-year postoperative CVA with high accuracy. For patients with type 1 and 2 (no LLD, with or without lower-extremity compensation), C7-intraoperative CSPL accurately predicted postoperative CVA up to 2-year follow-up (mean error 0.5 cm). For patients with type 3 and 4 (LLD, with or without lower-extremity compensation), iCVA accurately predicted postoperative CVA up to 2-year follow-up (mean error 0.4 cm).

Background: The study sought to evaluate the utility of a single supine radiograph in determining curve flexibility in early-onset scoliosis (EOS) patients. Methods: EOS patients with upright (standing/seated), supine, and side-bending radiographs who underwent spinal deformity surgery were identified. Coronal parameters included: proximal thoracic (PT) curve, main thoracic (MT) curve, and thoracolumbar/lumbar (TL/L) curve. Each radiograph was measured twice by 2 different raters. Correlation coefficients were utilized to investigate associations between the different radiographs. Interrater Correlation Coefficient (ICC) assessed intrarater and interrater reliability. Results: Thirty-seven EOS patients were identified (age at diagnosis: 7.0±2.9 y, preoperative age: 13.0±2.9 y; 73% female; etiologies: 54% idiopathic, 30% syndromic, and 16% neuromuscular). Supine PT and MT curve measurements were highly associated with corresponding side-bending measurements (PT: r =0.75, P <0.001; MT: r =0.80, P <0.001), and TL/L curves were very highly associated (TL/L: r =0.92, P <0.001). The mean absolute differences between supine and side-bending measurements were PT: 11.3±7.8 degrees, MT: 14.8±8.3 degrees, and TL/L: 16.2±7.6 degrees, where the side-bending was on average smaller than the supine measurement. The intrarater reliabilities were excellent, with an ICC ranging from 0.93 to 0.96 for side-bending films and 0.94 to 0.97 for supine films. The interrater reliability was excellent with ICC value of 0.88 for side-bending films and 0.93 for supine films. Conclusions: A single, preoperative supine radiograph was highly predictive of side-bending radiographs in patients with EOS. Supine curves measured an average of 15 degrees larger than bending curves in the MT and TL/L region. A single supine film may eliminate the need for effort-related, dual side-bending radiographs. Level of Evidence: Level II—retrospective study.

OBJECTIVE:There is a paucity of literature on pelvic fixation failure after adult spine surgery in the early postoperative period. The purpose of this study was to determine the incidence of acute pelvic fixation failure in a large single-center study and to describe the lessons learned.METHODS:The authors performed a retrospective review of adult (≥ 18 years old) patients who underwent spinal fusion with pelvic fixation (iliac, S2-alar-iliac [S2AI] screws) at a single academic medical center between 2015 and 2020. All patients had a minimum of 3 instrumented levels. The minimum follow-up was 6 months after the index spine surgery. Patients with prior pelvic fixation were excluded. Acute pelvic fixation failure was defined as revision of the pelvic screws within 6 months of the primary surgery. Patient demographics and operative, radiographic, and rod/screw parameters were collected. All rods were cobalt-chrome. All iliac and S2AI screws were closed-headed screws.RESULTS:In 358 patients, the mean age was 59.5 ± 13.6 years, and 64.0% (n = 229) were female. The mean number of instrumented levels was 11.5 ± 5.5, and 79.1% (n = 283) had ≥ 6 levels fused. Three-column osteotomies were performed in 14.2% (n = 51) of patients, and 74.6% (n = 267) had an L5-S1 interbody fusion. The mean diameter/length of pelvic screws was 8.5/86.6 mm. The mean number of pelvic screws was 2.2 ± 0.5, the mean rod diameter was 6.0 ± 0 mm, and 78.5% (n = 281) had > 2 rods crossing the lumbopelvic junction. Accessory rods extended to S1 (32.7%, n = 117) or S2/ilium (45.8%, n = 164). Acute pelvic fixation failure occurred in 1 patient (0.3%); this individual had a broken S2AI screw near the head-neck junction. This 76-year-old woman with degenerative lumbar scoliosis and chronic lumbosacral zone 1 fracture nonunion had undergone posterior instrumented fusion from T10 to pelvis with bilateral S2AI screws (8.5 × 90 mm); i.e., transforaminal lumbar interbody fusion L4-S1. The patient had persistent left buttock pain postoperatively, with radiographically confirmed breakage of the left S2AI screw 68 days after surgery. Revision included instrumentation removal at L2-pelvis and a total of 4 pelvic screws.CONCLUSIONS:The acute pelvic fixation failure rate was exceedingly low in adult spine surgery. This rate may be the result of multiple factors including the preference for multirod (> 2), closed-headed pelvic screw constructs in which large-diameter long screws are used. Increasing the number of rods and screws at the lumbopelvic junction may be important factors to consider, especially for patients with high risk for nonunion.

Medical malpractice litigation in the United States has resulted in the widespread adoption of defensive medicine practices. Orthopaedic surgery is among the specialties most likely to face a malpractice lawsuit, and hip-related surgeries are commonly involved. This study aimed to analyse malpractice litigation as it relates to hip surgery in the United States. The purpose of this study was to seek answers to the following questions: Has there been an increase or a decrease in the number of hip surgery malpractice cases in recent years? What are the most common reasons for a patient to pursue litigation? Which surgical complications are most likely to result in a lawsuit? What trends do we see in terms of outcomes? The Westlaw legal database was queried for all relevant cases from 2008 to 2018. A retrospective review of cases was conducted and descriptive analyses were performed in order to identify factors associated with hip surgery malpractice litigation. A total of 82 cases were analysed. There was a downtrend in the number of cases per year. Total hip arthroplasty (47 cases, 57.3%) was the procedure most often involved. Procedural error was noted as a reason for litigation in 71 (86.6%) cases. Neurological injury (22 cases, 26.8%), malpositioned hardware (15 cases, 18.3%) and leg length discrepancy (8 cases, 9.8%) were the most common complications listed. The majority of cases resulted in a verdict in favour of the defendant orthopaedic surgeon (48 cases, 58.5%). The mean payout for a plaintiff verdict (20 cases, 24.4%) was $1,647,981 (range, $1,852-$7,000,000) and the mean payout for a settlement (13 cases, 15.9%) was $657,823 (range, $49,000-$3,000,000) (p = 0.063). The study concluded that, within the 10-year period, there was a significant downtrend in hip surgery malpractice cases filed per year. Orthopaedic surgeons were found liable in the minority of cases. As expected, verdicts in favour of plaintiffs resulted in seemingly higher payouts than settlements.

INTRODUCTION:Due to a combination of poor respiratory muscle control and mechanical lung compression secondary to spine and chest wall deformities, patients with neuromuscular (NM) early-onset scoliosis (EOS) are at a high risk for pulmonary complications including pneumonia. The purpose of this study is to examine the effect of surgical intervention on the prevalence and risk of postoperative pneumonia in patients with NM EOS. METHODS:In this retrospective cohort study, pediatric (18 y old and below) patients with NM EOS undergoing index fusion or growth-friendly instrumentation from 2000 to 2018 were identified. Patients were then categorized into 2 groups: those with ≥50% curve correction and those with <50% curve correction of the coronal deformity at the first postoperative visit. The primary outcome of interest was postoperative pneumonia occurring between 3 weeks and 2 years postoperatively. Manual chart review was supplemented with phone call surveys to ensure all occurrences of preoperative/postoperative pneumonia (ie, in-institution and out-of-institution visits) were accounted for. RESULTS:A total of 35 patients (31% female, age at surgery: 10.3±4.3 y) with NM EOS met inclusion criteria. Twenty-three (66%) patients experienced at least 1 case of preoperative pneumonia. Twenty-six (74%) patients had ≥50% and 9 (26%) patients had <50% immediate postoperative curve correction. In total, 12 (34%) patients experienced at least 1 case of postoperative pneumonia (7 in-institution, 5 out-of-institution). Seven (27%) patients with ≥50% curve correction versus 5 (56%) with <50% curve correction experienced postoperative pneumonia. Relative risk regression demonstrated that patients with <50% curve correction had increased risk of postoperative pneumonia by 2.1 times compared with patients with ≥50% curve correction (95% confidence interval: 0.9; 4.9, P =0.099). CONCLUSION:The prevalence of preoperative and postoperative pneumonia is high in patients with NM EOS. This study presents preliminary evidence suggesting that percent curve correction is associated with the occurrence of postoperative pneumonia in patients with NM EOS undergoing surgical correction.

The purpose of this study was to determine the variability in clinical management of tibial tubercle fractures among a group of pediatric orthopedic surgeons. Nine fellowship-trained academic pediatric orthopedic surgeons reviewed 51 anteroposterior and lateral knee radiographs with associated case age. Respondents were asked to describe each fracture using the Ogden classification (type 1–5 with A/B modifiers), desired radiographic workup, operative vs. nonoperative treatment strategy and plans for post-treatment follow-up. Fair agreement was reached when classifying the fracture type using the Ogden classification (k = 0.39; P < 0.001). Overall, surgeons had a moderate agreement on whether to treat the fractures operatively vs. nonoperatively (k = 0.51; P < 0.001). Nonoperative management was selected for 80.4% (45/56) of type 1A fractures. Respondents selected operative treatment for 75% (30/40) of type 1B, 58.3% (14/24) of type 2A, 97.4% (74/76) of type 2B, 90.7% (39/43) of type 3A, 96.3% (79/82) of type 3B, 71.9% (87/121) of type 4 and 94.1% (16/17) of type 5 fractures. Regarding operative treatment, fair/slight agreement was reached when selecting the specifics of operative treatment including surgical fixation technique (k = 0.25; P < 0.001), screw type (k = 0.26; P < 0.001), screw size (k = 0.08; P < 0.001), use of washers (k = 0.21; P < 0.001) and performing a prophylactic anterior compartment fasciotomy (k = 0.20; P < 0.001). Furthermore, surgeons had fair/moderate agreement regarding the specifics of nonoperative treatment including degree of knee extension during immobilization (k = 0.46; P < 0.001), length of immobilization (k = 0.34; P < 0.001), post-treatment weight bearing status (k = 0.30; P < 0.001) and post-treatment rehabilitation (k = 0.34; P < 0.001). Significant variability exists between surgeons when evaluating and treating pediatric tibial tubercle fractures.

OBJECTIVE:The purpose of this study was to determine the incidence, mechanism, and potential protective strategies for pelvic fixation failure (PFF) within 2 years after adult spinal deformity (ASD) surgery. METHODS:Data for ASD patients (age ≥ 18 years, minimum of six instrumented levels) with pelvic fixation (S2-alar-iliac [S2AI] and/or iliac screws) with a minimum 2-year follow-up were consecutively collected (2015-2019). Patients with prior pelvic fixation were excluded. PFF was defined as any revision to pelvic screws, which may include broken rods across the lumbosacral junction requiring revision to pelvic screws, pseudarthrosis across the lumbosacral junction requiring revision to pelvic screws, a broken or loose pelvic screw, or sacral/iliac fracture. Patient information including demographic data and health history (age, sex, BMI, smoking status, American Society of Anesthesiologists score, osteoporosis), operative (total instrumented levels [TIL], three-column osteotomy [3CO], interbody fusion), screw (iliac, S2AI, length, diameter), rod (diameter, kickstand), rod pattern (number crossing lumbopelvic junction, lowest instrumented vertebra [LIV] of accessory rod[s], lateral connectors, dual-headed screws), and pre- and postradiographic (lumbar lordosis, pelvic incidence, pelvic tilt, major Cobb angle, lumbosacral fractional curve, C7 coronal vertical axis [CVA], T1 pelvic angle, C7 sagittal vertical axis) parameters was collected. All rods across the lumbosacral junction were cobalt-chrome. All iliac and S2AI screws were closed-headed tulips. Both univariate and multivariate analyses were performed to determine risk factors for PFF. RESULTS:Of 253 patients (mean age 58.9 years, mean TIL 13.6, 3CO 15.8%, L5-S1 interbody 74.7%, mean pelvic screw diameter/length 8.6/87 mm), the 2-year failure rate was 4.3% (n = 11). The mechanisms of failure included broken rods across the lumbosacral junction (n = 4), pseudarthrosis across the lumbosacral junction requiring revision to pelvic screws (n = 3), broken pelvic screw (n = 1), loose pelvic screw (n = 1), sacral/iliac fracture (n = 1), and painful/prominent pelvic screw (n = 1). A higher number of rods crossing the lumbopelvic junction (mean 3.8 no failure vs 2.9 failure, p = 0.009) and accessory rod LIV to S2/ilium (no failure 54.2% vs failure 18.2%, p = 0.003) were protective for failure. Multivariate analysis demonstrated that accessory rod LIV to S2/ilium versus S1 (OR 0.2, p = 0.004) and number of rods crossing the lumbar to pelvis (OR 0.15, p = 0.002) were protective, while worse postoperative CVA (OR 1.5, p = 0.028) was an independent risk factor for failure. CONCLUSIONS:The 2-year PFF rate was low relative to what is reported in the literature, despite patients undergoing long fusion constructs for ASD. The number of rods crossing the lumbopelvic junction and accessory rod LIV to S2/ilium relative to S1 alone likely increase construct stiffness. Residual postoperative coronal malalignment should be avoided to reduce PFF.

Introduction: Multicenter clinical research is critically important in a constantly evolving landscape, particularly in early onset scoliosis (EOS). There is variability from center to center with regard to the “quality of participation” in such research efforts as well as publications on EOS. The purpose of this study was to examine factors associated with “high-performing” centers. Methods: This was a multicenter retrospective cohort study of 21 academic medical centers participating in an EOS registry. Factors examined include research personnel, spine research focus, and regular participation of faculty in research, collected through an eight-question survey. Outcomes included the quality of participation in the study group, derived from quarterly site reports generated by the registry, and average annual publication volume of each institution obtained from a PubMed search. Univariable analyses were utilized to investigate institutional factors associated with the quality of performance and publication volume. Results: All 21 sites completed the survey. Centers with full-time spine research staff had higher average quality of participation scores (90 vs. 60, p=0.026) as did centers with dedicated spine research meetings (90 vs. 70, p = 0.074) than those that lacked these features. Additionally, centers with higher average publication volumes were more likely to have full-time research staff (8.0 vs. 3.5, p = 0.115), a research team focused on spine (8.9 vs. 4.8, 0.067), and a dedicated physician assistant (PA) or nurse with >95% focus on spine (9.0 vs. 5.4, p = 0.107). Conclusion: The single most important and significant factor in quality of participation in the study group was a center having full-time research staff, with research meetings dedicated to spine being nearly significant. Factors most predictive of publications was a research team focused primarily on spine and a spine dedicated PA or nurse. If institutions want to improve spine research, we recommend investing in these factors.

Background: Limiting complications, especially unplanned return to the operating room (UPROR), is a major focus in the surgical management of early-onset scoliosis (EOS). Although UPROR remains common in this population, its effect on long-term health-related quality of life (HRQoL) remains unclear. The purpose of this study was to investigate the association between UPROR and end-of-treatment HRQoL in EOS patients treated with growth-friendly instrumentation. Methods: Patients with EOS who underwent growth-friendly instrumentation at age less than 10 years from 1993 to 2018, and completed treatment, were identified in a multicenter EOS registry. UPROR events were recorded, and end-of-treatment (defined as skeletal maturity and/or definitive spinal fusion) HRQoL was assessed via the 24-item Early-Onset Scoliosis Questionnaire (EOSQ-24). Results: A total of 825 patients were identified, and 325 patients (age at surgery: 6.4 y, follow-up: 8.1 y) had end-of-treatment HRQoL data necessary for our investigation. Overall, 129/325 (39.7%) patients experienced 264 UPROR events; the majority (54.2%) were implant-related. Aside from age and etiology, no other variables were determined to be confounders or effect modifiers. Congenital patients with UPROR had worse pain/discomfort by 10.4 points ( P =0.057) and worse pulmonary function by 7.8 points ( P =0.102) compared with non-UPROR patients adjusting for age. Neuromuscular patients with UPROR had worse pulmonary function by 10.1 points compared with non-UPROR patients adjusting for age ( P =0.037). Idiopathic and syndromic patients with UPROR reported consistently worse domain scores than their non-UPROR counterparts, but smaller (<5-point) differences were seen. Conclusions: UPROR during growth-friendly surgical treatment for EOS is associated with worse HRQoL in all patients, but particularly in those with neuromuscular or congenital etiologies. Ongoing efforts to avoid UPROR are critical. Level of Evidence: Level II. This is a multicenter retrospective cohort study investigating the effect of UPROR on HRQoL (prognostic study).

BACKGROUND CONTEXT The aim of complex spinal deformity correction is to restore both sagittal and coronal balance of the spine. Many studies have shown adverse clinical outcomes related to under and over corrected sagittal and coronal deformities. With proper surgical planning, such under and over correction can be mitigated and patient outcomes can be improved and other complications, such as PJK, can be minimized. PURPOSE Precontoured rod instrumentation for adult spinal deformity (ASD) can accurately achieve planned alignment parameters in the sagittal and coronal planes. STUDY DESIGN/SETTING Multicentered cohort. PATIENT SAMPLE Adult patients (age 18) undergoing instrumentation with pre-contoured rods from 2018-2021. OUTCOME MEASURES Sagittal parameters included C2 slope, cervical lordosis (CL), C2 pelvic angle (CPA), cervicothoracic pelvic angle (CTPA), lumbar lordosis (LL), pelvic incidence (PI), PI-LL, pelvic tilt (PT), sacral slope (SS), sagittal vertical axis (SVA), T1 spinopelvic inclination (T1SPI), T1 slope, T1 slope-CL (T1 slope-CL), thoracic kyphosis (TK), T1 pelvic angle (TPA), C2-C7 SVA (cSVA). Coronal parameters included major coronal curve (MCC) and coronal balance (CVA). METHODS A multicenter cohort of adult patients (age 18) undergoing instrumentation with pre-contoured rods was reviewed from 2018-2021. RESULTS A total of 289 patients were included in the study (mean age: 61.3±13.5yrs, 156 (54%) female, mean total instrumented levels: 8.2±5.0). At 6mo followup, the preoperative plan accurately predicted CL, MCC, and CVA with 71 (62.8%), 33 (68.6%) and 37 (69.8%) patients meeting acceptable criteria (ie, difference of ≤5° or ≤10mm), respectively. However, by 2yrs, accuracy in predicting regional parameters improved including LL (mean error: -3.9±10.2°; P=0.064), PI-LL (-2±9.1°; P=0.265), PT (0.05±5.7°; P=0.968), TK (-6.0±11.3°; 0.059). Similarly, mean errors for global parameters including T1SPI (-1.8±4.2°; 0.126), TPA (-1.8±5.7°, 0.233) and CVA (-1.4±16.8mm, 0.874) were low and statistically insignificant. Although mean differences between plan and 2yr postop for CPA, CTPA, SVA and cSVA were statistically significant, the mean error was 20mm, respectively proving a small clinical difference. CONCLUSIONS In the first and largest, multicenter study with 2-year followup evaluating use of pre-contoured rods, we found high accuracy for both coronal and sagittal correction (regionally and globally) in predicting postoperative alignment parameters. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs. The aim of complex spinal deformity correction is to restore both sagittal and coronal balance of the spine. Many studies have shown adverse clinical outcomes related to under and over corrected sagittal and coronal deformities. With proper surgical planning, such under and over correction can be mitigated and patient outcomes can be improved and other complications, such as PJK, can be minimized. Precontoured rod instrumentation for adult spinal deformity (ASD) can accurately achieve planned alignment parameters in the sagittal and coronal planes. Multicentered cohort. Adult patients (age 18) undergoing instrumentation with pre-contoured rods from 2018-2021. Sagittal parameters included C2 slope, cervical lordosis (CL), C2 pelvic angle (CPA), cervicothoracic pelvic angle (CTPA), lumbar lordosis (LL), pelvic incidence (PI), PI-LL, pelvic tilt (PT), sacral slope (SS), sagittal vertical axis (SVA), T1 spinopelvic inclination (T1SPI), T1 slope, T1 slope-CL (T1 slope-CL), thoracic kyphosis (TK), T1 pelvic angle (TPA), C2-C7 SVA (cSVA). Coronal parameters included major coronal curve (MCC) and coronal balance (CVA). A multicenter cohort of adult patients (age 18) undergoing instrumentation with pre-contoured rods was reviewed from 2018-2021. A total of 289 patients were included in the study (mean age: 61.3±13.5yrs, 156 (54%) female, mean total instrumented levels: 8.2±5.0). At 6mo followup, the preoperative plan accurately predicted CL, MCC, and CVA with 71 (62.8%), 33 (68.6%) and 37 (69.8%) patients meeting acceptable criteria (ie, difference of ≤5° or ≤10mm), respectively. However, by 2yrs, accuracy in predicting regional parameters improved including LL (mean error: -3.9±10.2°; P=0.064), PI-LL (-2±9.1°; P=0.265), PT (0.05±5.7°; P=0.968), TK (-6.0±11.3°; 0.059). Similarly, mean errors for global parameters including T1SPI (-1.8±4.2°; 0.126), TPA (-1.8±5.7°, 0.233) and CVA (-1.4±16.8mm, 0.874) were low and statistically insignificant. Although mean differences between plan and 2yr postop for CPA, CTPA, SVA and cSVA were statistically significant, the mean error was 20mm, respectively proving a small clinical difference. In the first and largest, multicenter study with 2-year followup evaluating use of pre-contoured rods, we found high accuracy for both coronal and sagittal correction (regionally and globally) in predicting postoperative alignment parameters.