Is the information provided by large language models valid in educating patients about adolescent idiopathic scoliosis? An evaluation of content, clarity, and empathy : The perspective of the European Spine Study Group.

PURPOSE: Large language models (LLM) have the potential to bridge knowledge gaps in patient education and enrich patient-surgeon interactions. This study evaluated three chatbots for delivering empathetic and precise adolescent idiopathic scoliosis (AIS) related information and management advice. Specifically, we assessed the accuracy, clarity, and relevance of the information provided, aiming to determine the effectiveness of LLMs in addressing common patient queries and enhancing their understanding of AIS. METHODS: We sourced 20 webpages for the top frequently asked questions (FAQs) about AIS and formulated 10 critical questions based on them. Three advanced LLMs-ChatGPT 3.5, ChatGPT 4.0, and Google Bard-were selected to answer these questions, with responses limited to 200 words. The LLMs' responses were evaluated by a blinded group of experienced deformity surgeons (members of the European Spine Study Group) from seven European spine centers. A pre-established 4-level rating system from excellent to unsatisfactory was used with a further rating for clarity, comprehensiveness, and empathy on the 5-point Likert scale. If not rated 'excellent', the raters were asked to report the reasons for their decision for each question. Lastly, raters were asked for their opinion towards AI in healthcare in general in six questions. RESULTS: The responses among all LLMs were 'excellent' in 26% of responses, with ChatGPT-4.0 leading (39%), followed by Bard (17%). ChatGPT-4.0 was rated superior to Bard and ChatGPT 3.5 (p = 0.003). Discrepancies among raters were significant (p < 0.0001), questioning inter-rater reliability. No substantial differences were noted in answer distribution by question (p = 0.43). The answers on diagnosis (Q2) and causes (Q4) of AIS were top-rated. The most dissatisfaction was seen in the answers regarding definitions (Q1) and long-term results (Q7). Exhaustiveness, clarity, empathy, and length of the answers were positively rated (> 3.0 on 5.0) and did not demonstrate any differences among LLMs. However, GPT-3.5 struggled with language suitability and empathy, while Bard's responses were overly detailed and less empathetic. Overall, raters found that 9% of answers were off-topic and 22% contained clear mistakes. CONCLUSION: Our study offers crucial insights into the strengths and weaknesses of current LLMs in AIS patient and parent education, highlighting the promise of advancements like ChatGPT-4.o and Gemini alongside the need for continuous improvement in empathy, contextual understanding, and language appropriateness.

Fat beyond muscle: Assessing epimuscular fat of the lumbar spine and its association with vertebral level, demographics, BMI, and low back pain.

Introduction: Epimuscular fat (EF) has rarely been studied in the context of low back pain (LBP). Research question: This study aims to assess the presence and extent of EF in the lumbar muscles and its association with vertebral level in patients with low back disorders and to explore correlations between EF, demographics, BMI, and LBP. Material and methods: T2 axial MRIs from L1 to L5 were manually segmented to analyze the cross-sectional area (CSA) of EF (mm2), and fat infiltration (FI,%) of 40 patients (23 females, 17 males; mean age:65.9 years) with lumbar degenerative pathologies awaiting a surgical procedure. COMI, LBP, demographic, and clinical data were extracted from the institutional registry. Statistical analyses included Wilcoxon and Mann-Whitney tests for differences in EF between sides and sexes, the Friedman test for EF size differences among lumbar levels, and Spearman's correlation for associations, adjusted for BMI, age, and sex. Results: EF was found in 77.5% of subjects at L1, 92.5% at L2, 100% at L3 and L4, and 95.0% at L5. EF was significantly larger at L4 (253.1 ± 183.6 mm2) and L5 (220.2 ± 194.9 mm2) than at L1 (36.1 ± 37.8 mm2) and L2 (72.2 ± 84.4 mm2). No significant EF differences were found between sides and sexes. EF correlated strongly with BMI (rs = 0.65,p < 0.001) and moderately with FI (rs = 0.31,p = 0.04), though its correlation with FI was not significant after adjustment. EF did not correlate with COMI scores but correlated with LBP in the adjusted analysis (rs:0.31,p = 0.04). Discussion and conclusion: EF is present across all lumbar levels, with higher concentrations at L4 and L5, and a significant correlation between EF and LBP intensity was observed. The present findings are limited to a specific subset of patients with lumbar degenerative disorders who are awaiting surgical procedures.

Methodological considerations in calculating the minimal clinically important change score for the core outcome measures index (COMI): insights from a large single-centre spine surgery registry.

INTRODUCTION: The Minimal Clinically Important Change (MCIC) is used in conjunction with Patient-Reported Outcome Measures (PROMs) to determine the clinical relevance of changes in health status. MCIC measures a change within the same person or group over time. This study aims to evaluate the variability in computing MCIC for the Core Outcome Measure Index (COMI) using different methods. METHODS: Data from a spine centre in Switzerland were used to evaluate variations in MCIC for the COMI score. Distribution-based and anchor-based methods (predictive and nonpredictive) were applied. Bayesian bootstrap estimated confidence intervals. RESULTS: From 27,003 cases, 9821 met the inclusion criteria. Distribution-based methods yielded MCIC values from 0.4 to 1.4. Anchor-based methods showed more variability, with MCIC values from 1.5 to 4.9. Predictive anchor-based methods also provided variable MCIC values for improvement (0.3-2.4), with high sensitivity and specificity. DISCUSSION: MCIC calculation methods produce varying values, emphasizing careful method selection. Distribution-based methods likely measure minimal detectable change, while non-predictive anchor-based methods can yield high MCIC values due to group averaging. Predictive anchor-based methods offer more stable and clinically relevant MCIC values for improvement but are affected by prevalence and reliability corrections.

Patient-reported outcome of lumbar decompression with instrumented fusion for low-grade spondylolisthesis: influence of pathology and baseline symptoms.

INTRODUCTION: Low-grade isthmic and degenerative spondylolisthesis (DS) of the lumbar spine are distinct pathologies but both can be treated with lumbar decompression with fusion. In a very large cohort, we compared patient-reported outcome in relation to the pathology and chief complaint at baseline. METHODS: This was a retrospective analysis using the EUROSPINE Spine Tango Registry. We included 582 patients (age 60 ± 15 years; 65% female), divided into four groups based on two variables: type of spondylolisthesis and chief pain complaint (leg pain (LP) versus back pain). Patients completed the COMI preoperatively and up to 5 years follow-up (FU), and rated global treatment outcome (GTO). Regression models were used to predict COMI-scores at FU. Pain scores and satisfaction ratings were analysed. RESULTS: All patients experienced pronounced reductions in COMI scores. Relative to the other groups, the DS-LP group showed between 5% and 11% greater COMI score reduction (p < 0.01 up to 2 years' FU). This group also performed best with respect to pain outcomes and satisfaction. Long-term GTO was 93% at the 5 year FU, compared with between 82% and 86% in the other groups. CONCLUSION: Regardless of the type of spondylolisthesis, all groups experienced an improvement in COMI score after surgery. Patients with DS and LP as their chief complaint appear to benefit more than other patients. These results are the first to show that the type of the spondylolisthesis and its chief complaint have an impact on surgical outcome. They will be informative for the consent process prior to surgery and can be used to build predictive models for individual outcome.

Estimating lumbar bone mineral density from conventional MRI and radiographs with deep learning in spine patients.

PURPOSE: This study aimed to develop machine learning methods to estimate bone mineral density and detect osteopenia/osteoporosis from conventional lumbar MRI (T1-weighted and T2-weighted images) and planar radiography in combination with clinical data and imaging parameters of the acquisition protocol. METHODS: A database of 429 patients subjected to lumbar MRI, radiographs and dual-energy x-ray absorptiometry within 6 months was created from an institutional database. Several machine learning models were trained and tested (373 patients for training, 86 for testing) with the following objectives: (1) direct estimation of the vertebral bone mineral density; (2) classification of T-score lower than - 1 or (3) lower than - 2.5. The models took as inputs either the images or radiomics features derived from them, alone or in combination with metadata (age, sex, body size, vertebral level, parameters of the imaging protocol). RESULTS: The best-performing models achieved mean absolute errors of 0.15-0.16 g/cm2 for the direct estimation of bone mineral density, and areas under the receiver operating characteristic curve of 0.82 (MRIs) - 0.80 (radiographs) for the classification of T-scores lower than - 1, and 0.80 (MRIs) - 0.65 (radiographs) for T-scores lower than - 2.5. CONCLUSIONS: The models showed good discriminative performances in detecting cases of low bone mineral density, and more limited capabilities for the direct estimation of its value. Being based on routine imaging and readily available data, such models are promising tools to retrospectively analyse existing datasets as well as for the opportunistic investigation of bone disorders.

Cyclic testing of standalone ALIF versus TLIF in lumbosacral spines of low bone mineral density: an ex vivo biomechanical study.

PURPOSE: Screwed anterior lumbar interbody fusion (SALIF) alleviates the need for supplemental posterior fixation leading to reduction of perioperative morbidity. Specifically, elderly and multimorbid patients would benefit from shorter operative time and faster recovery but tend to have low bone mineral density (BMD). The current study aimed to compare loosening, defined as increase of ROM and NZ, of SALIF versus transforaminal lumbar interbody fusion (TLIF) under cyclic loading in cadaveric spines with reduced BMD. METHODS: Twelve human spines (L4-S2; 6 male 6 female donors; age 70.6 ± 19.6; trabecular BMD of L5 84.2 ± 24.4 mgHA/cm3, range 51-119 mgHA/cm3) were assigned to two groups. SALIF or TLIF were instrumented at L5/S1. Range of motion (ROM) and neutral zone (NZ) were assessed before and after axial cyclic loading (0-1150 N, 2000 cycles, 0.5 Hz) in flexion-extension (Flex-Ext), lateral bending, (LB), axial rotation (AR). RESULTS: ROM of the SALIF specimens increased significantly in all loading directions (p ≤ 0.041), except for left AR (p = 0.053), whereas for TLIF it increased significantly in left LB (p = 0.033) and Flex (p = 0.015). NZ of SALIF showed increase in Flex-Ext and LB, whereas NZ of TLIF did not increase significantly in any motion direction. CONCLUSIONS: Axial compression loading caused loosening of SALIF in Flex-Ext and LB, but not TLIF at L5/S1 in low BMD specimens. Nevertheless, Post-cyclic ROM and NZ of SALIF is comparable to TLIF. This suggests that, neither construct is optimal for the use in patients with reduced BMD.

Optically Actuated Soft Microrobot Family for Single-Cell Manipulation.

Precisely controlled manipulation of nonadherent single cells is often a pre-requisite for their detailed investigation. Optical trapping provides a versatile means for positioning cells with submicrometer precision or measuring forces with femto-Newton resolution. A variant of the technique, called indirect optical trapping, enables single-cell manipulation with no photodamage and superior spatial control and stability by relying on optically trapped microtools biochemically bound to the cell. High-resolution 3D lithography enables to prepare such cell manipulators with any predefined shape, greatly extending the number of achievable manipulation tasks. Here, it is presented for the first time a novel family of cell manipulators that are deformable by optical tweezers and rely on their elasticity to hold cells. This provides a more straightforward approach to indirect optical trapping by avoiding biochemical functionalization for cell attachment, and consequently by enabling the manipulated cells to be released at any time. Using the photoresist Ormocomp, the deformations achievable with optical forces in the tens of pN range and present three modes of single-cell manipulation as examples to showcase the possible applications such soft microrobotic tools can offer are characterized. The applications describe here include cell collection, 3D cell imaging, and spatially and temporally controlled cell-cell interaction.

Are large language models valid tools for patient information on lumbar disc herniation? The spine surgeons' perspective.

Introduction: Generative AI is revolutionizing patient education in healthcare, particularly through chatbots that offer personalized, clear medical information. Reliability and accuracy are vital in AI-driven patient education. Research question: How effective are Large Language Models (LLM), such as ChatGPT and Google Bard, in delivering accurate and understandable patient education on lumbar disc herniation? Material and methods: Ten Frequently Asked Questions about lumbar disc herniation were selected from 133 questions and were submitted to three LLMs. Six experienced spine surgeons rated the responses on a scale from "excellent" to "unsatisfactory," and evaluated the answers for exhaustiveness, clarity, empathy, and length. Statistical analysis involved Fleiss Kappa, Chi-square, and Friedman tests. Results: Out of the responses, 27.2% were excellent, 43.9% satisfactory with minimal clarification, 18.3% satisfactory with moderate clarification, and 10.6% unsatisfactory. There were no significant differences in overall ratings among the LLMs (p = 0.90); however, inter-rater reliability was not achieved, and large differences among raters were detected in the distribution of answer frequencies. Overall, ratings varied among the 10 answers (p = 0.043). The average ratings for exhaustiveness, clarity, empathy, and length were above 3.5/5. Discussion and conclusion: LLMs show potential in patient education for lumbar spine surgery, with generally positive feedback from evaluators. The new EU AI Act, enforcing strict regulation on AI systems, highlights the need for rigorous oversight in medical contexts. In the current study, the variability in evaluations and occasional inaccuracies underline the need for continuous improvement. Future research should involve more advanced models to enhance patient-physician communication.

The use of the Core Yellow Flags Index for the assessment of psychosocial distress in patients undergoing surgery of the cervical spine.

BACKGROUND: Psychosocial distress (the presence of yellow flags) has been linked to poor outcomes in spine surgery. The Core Yellow Flags Index (CYFI), a short instrument assessing the 4 main yellow flags, was developed for use in patients undergoing lumbar spine surgery. This study evaluated its ability to predict outcome in patients undergoing cervical spine surgery. METHODS: Patients with degenerative spinal disorders (excluding myelopathy) operated in one centre, from 2015 to 2019, were asked to complete the CYFI at baseline and the Core Outcome Measures Index (COMI) at baseline and 3 and 12 months after surgery. The relationship between CYFI and COMI scores at baseline as well as the predictive ability of the CYFI on the COMI follow-up scores were tested using structural equation modelling. RESULTS: From 731 eligible patients, 547 (61.0 ± 12.5 years; 57.2% female) completed forms at all three timepoints. On a cross-sectional basis, preoperative CYFI and COMI scores were highly correlated (ß = 0.54, in men and 0.51 in women; each p < 0.001). CYFI added significantly and independently to the prediction of COMI at 3 months' FU in men (ß = 0.36) and 12 months' FU in men and women (both ß = 0.20) (all p < 0.001). CONCLUSION: The CYFI had a low to moderate but significant and independent association with cervical spine surgery outcomes. Implementing the CYFI in the preoperative workup of these patients could help refine outcome predictions and better manage patient expectations.

Surgical outcome after treatment of thoracolumbar spinal stenosis in adults with achondroplasia.

PURPOSE: To describe the complications and the outcome of patients with achondroplasia undergoing thoracolumbar spinal surgery. METHODS: Retrospective analysis of prospectively collected data of all patients with achondroplasia undergoing surgery within the years 1992-2021 at the thoracic and/or lumbar spine. The outcome was measured by analyzing the surgical complications and revisions. The patient-rated outcome was assessed with the COMI score from 2005 onwards. RESULTS: A total of 15 patients were included in this study undergoing a total of 31 surgeries at 79 thoracolumbar levels. 12/31 surgeries had intraoperative complications consisting of 11 dural tears and one excessive intraoperative bleeding. 4/18 revision surgeries were conducted due to post-decompression hyperkyphosis. The COMI score decreased from 7.5 IQR 1.4 (range 7.1-9.8) preoperatively to 5.3 IQR 4.1 (2.5-7.5) after 2 years (p = 0.046). CONCLUSION: Patients with achondroplasia, the most common skeletal dysplasia condition with short-limb dwarfism, are burdened with a congenitally narrow spinal canal and are commonly in need of spinal surgery. However, surgery in these patients is often associated with complications, namely dural tears and post-decompression kyphosis. Despite these complications, patients benefit from surgical treatment at a follow-up of 2 years after surgery.

Comparing image normalization techniques in an end-to-end model for automated modic changes classification from MRI images.

Introduction: Modic Changes (MCs) are MRI alterations in spine vertebrae's signal intensity. This study introduces an end-to-end model to automatically detect and classify MCs in lumbar MRIs. The model's two-step process involves locating intervertebral regions and then categorizing MC types (MC0, MC1, MC2) using paired T1-and T2-weighted images. This approach offers a promising solution for efficient and standardized MC assessment. Research question: The aim is to investigate how different MRI normalization techniques affect MCs classification and how the model can be used in a clinical setting. Material and methods: A combination of Faster R-CNN and a 3D Convolutional Neural Network (CNN) is employed. The model first identifies intervertebral regions and then classifies MC types (MC0, MC1, MC2) using paired T1-and T2-weighted lumbar MRIs. Two datasets are used for model development and evaluation. Results: The detection model achieves high accuracy in identifying intervertebral areas, with Intersection over Union (IoU) values above 0.7, indicating strong localization alignment. Confidence scores above 0.9 demonstrate the model's accurate levels identification. In the classification task, standardization proves the best performances for MC type assessment, achieving mean sensitivities of 0.83 for MC0, 0.85 for MC1, and 0.78 for MC2, along with balanced accuracy of 0.80 and F1 score of 0.88. Discussion and conclusion: The study's end-to-end model shows promise in automating MC assessment, contributing to standardized diagnostics and treatment planning. Limitations include dataset size, class imbalance, and lack of external validation. Future research should focus on external validation, refining model generalization, and improving clinical applicability.

AO Spine Guideline for the Use of Osteobiologics (AOGO) in Anterior Cervical Discectomy and Fusion for Spinal Degenerative Cases.

STUDY DESIGN: Guideline. OBJECTIVES: To develop an international guideline (AOGO) about the use of osteobiologics in anterior cervical discectomy and fusion (ACDF) for treating degenerative spine conditions. METHODS: The guideline development process was guided by AO Spine Knowledge Forum Degenerative (KF Degen) and followed the Guideline International Network McMaster Guideline Development Checklist. The process involved 73 participants with expertise in degenerative spine diseases and surgery from 22 countries. Fifteen systematic reviews were conducted addressing respective key topics and evidence was collected. The methodologist compiled the evidence into GRADE Evidence-to-Decision frameworks. Guideline panel members judged the outcomes and other criteria and made the final recommendations through consensus. RESULTS: Five conditional recommendations were created. A conditional recommendation is about the use of allograft, autograft or a cage with an osteobiologic in primary ACDF surgery. Other conditional recommendations are about the use of osteobiologic for single- or multi-level ACDF, and for hybrid construct surgery. It is suggested that surgeons use other osteobiologics rather than human bone morphogenetic protein-2 (BMP-2) in common clinical situations. Surgeons are recommended to choose 1 graft over another or 1 osteobiologic over another primarily based on clinical situation, and the costs and availability of the materials. CONCLUSION: This AOGO guideline is the first to provide recommendations for the use of osteobiologics in ACDF. Despite the comprehensive searches for evidence, there were few studies completed with small sample sizes and primarily as case series with inherent risks of bias. Therefore, high-quality clinical evidence is demanded to improve the guideline.

Evaluation of "appropriate use criteria" for surgical decision-making in lumbar degenerative spondylolisthesis. A controlled, multicentre, prospective observational study.

INTRODUCTION: Selecting patients with lumbar degenerative spondylolisthesis (LDS) for surgery is difficult. Appropriate use criteria (AUC) have been developed to clarify the indications for LDS surgery but have not been evaluated in controlled studies. METHODS: This prospective, controlled, multicentre study involved 908 patients (561 surgical and 347 non-surgical controls; 69.5 ± 9.7y; 69% female), treated as per normal clinical practice. Their appropriateness for surgery was afterwards determined using the AUC. They completed the Core Outcome Measures Index (COMI) at baseline and 12 months' follow-up. Multiple regression adjusting for confounders evaluated the influence of appropriateness designation and treatment received on the 12-month COMI and achievement of MCIC (≥ 2.2-point-reduction). RESULTS: As per convention, appropriate (A) and uncertain (U) groups were combined for comparison with the inappropriate (I) group. For the adjusted 12-month COMI, the benefit of surgery relative to non-surgical care was not significantly greater for the A/U than the I group (p = 0.189). There was, however, a greater treatment effect of surgery for those with higher baseline COMI (p = 0.035). The groups' adjusted probabilities of achieving MCIC were: 83% (A/U, receiving surgery), 71% (I, receiving surgery), 50% (A/U, receiving non-surgical care), and 32% (I, receiving non-surgical care). CONCLUSIONS: A/U patients receiving surgery had the highest chances of achieving MCIC, but the AUC were not able to identify which patients had a greater treatment effect of surgery relative to non-surgical care. The identification of other characteristics that predict a greater treatment effect of surgery, in addition to baseline COMI, is required to improve decision-making.

A decade of experience in over 300 surgically treated spine patients with long-term oral anticoagulation: a propensity score matched cohort study.

PURPOSE: The aim of this study was to investigate the risks and outcomes of patients with long-term oral anticoagulation (OAC) undergoing spine surgery. METHODS: All patients on long-term OAC who underwent spine surgery between 01/2005 and 06/2015 were included. Data were prospectively collected within our in-house Spine Surgery registry and retrospectively supplemented with patient chart and administrative database information. A 1:1 propensity score-matched group of patients without OAC from the same time interval served as control. Primary outcomes were post-operative bleeding, wound complications and thromboembolic events up to 90 days post-surgery. Secondary outcomes included intraoperative blood loss, length of hospital stay, death and 3-month post-operative patient-rated outcomes. RESULTS: In comparison with the control group, patients with OAC (n = 332) had a 3.4-fold (95%CI 1.3-9.0) higher risk for post-operative bleeding, whereas the risks for wound complications and thromboembolic events were comparable between groups. The higher bleeding risk was driven by a higher rate of extraspinal haematomas (3.3% vs. 0.6%; p = 0.001), while there was no difference in epidural haematomas and haematoma evacuations. Risk factors for adverse events among patients with OAC were mechanical heart valves, posterior neck surgery, blood loss > 1000 mL, age, female sex, BMI > 30 kg/m2 and post-operative PTT levels. At 3-month follow-up, most patients reported favourable outcomes with no difference between groups. CONCLUSION: Although OAC patients have a higher risk for complications after spine surgery, the risk for major events is low and patients benefit similarly from surgery.

Patient-reported outcomes 1 and 2 years after transforaminal thoracic interbody fusion (TTIF).

STUDY DESIGN: Retrospective Cohort Study with prospectively collected data. PURPOSE: Transforaminal interbody fusion was initially designed for the lumbar spine. A similar approach was later introduced for the thoracic spine (TTIF). Here we report the surgical technique and the Core Outcome Measures Index (COMI) at 1-year and 2-year follow-ups, as well as the sagittal radiographic kyphosis correction of TTIF, achieved at 1 year and the latest follow-up. METHODS: All TTIF procedures from 2012 to 2020 were included. COMI scores were collected preoperatively and at 1- and 2-year follow-ups. The sagittal angle between the upper and lower endplates at the segment where TTIF was performed was measured on preoperative, 1-year postoperative, and last available radiographs. RESULTS: Seventy-nine TTIF procedures were performed for 64 patients (36% males; mean age 67.5 (SD 15.3) years). COMI score reduced from a mean value of 8.1 (SD 1.4) preoperatively to 4.7 (SD 2.7) at 1-year follow-up and 4.7 (SD 2.7) at 2-year follow-up. The mean correction of segmental kyphosis was 10.8 (SD 7.3, p < 0.0001) degrees at 1-year follow-up and 9.3 (SD 7.0, p < 0.0001) degrees at the final follow-up 3.4 (SD 1.4) years after the operation. Kaplan-Meier analysis for reoperations showed a 5-year survival of 91% (95% CI 0.795-1) for primary TTIF operations and survival of 77% (95% CI 0.651-0.899) for TTIFs performed after earlier fusion operations. CONCLUSIONS: TTIF is a feasible procedure in the thoracic spine. Kyphosis correction of approximately 10° was maintained at 1-year and final follow-up. Over 69% at 1-year and 61% at 2-year follow-up achieved MCID for COMI.

Far Lateral Lumbar Decompression Using the Far-Lateral Approach: Patient Reported Outcome is Associated with the Involved Vertebral Level and Coronal Segmental Angle.

STUDY DESIGN: Single centre retrospective study of prospectively collected data. OBJECTIVE: Analyse factors associated with patient reported outcome after far lateral decompression surgery (FLDS) for lumbar nerve root compression using the far-lateral approach. SUMMARY OF BACKGROUND DATA: To date, no studies have investigated the influence of vertebral level, coronal segmental Cobb angle, and the nature of the compressive tissue (hard/soft) on patient reported outcome following FLDS. METHODS: Patients who had undergone FLDS between 2005 and 2020 were included. Coronal segmental angle (CSCA) was measured on preoperative, posteroanterior radiographs. Primary outcome measure was the Core Outcome Measures Index (COMI) score at 2 years' follow-up (2Y-FU). Patients who had undergone microsurgical decompression using a midline approach (MID) served as a comparator group. RESULTS: There were 148 FLDS and 463 MID patients. In both groups there was a significant improvement in COMI score from preoperative to 2Y-FU (P<0.0001), with greater improvement in patients treated at higher vertebral levels than in those treated at L5/S1 (P=0.014). Baseline COMI, ASA grade, BMI, and low back pain as the "chief complaint" all had a significant association with the 2-year COMI score. The nature of compressive tissue showed no association with COMI score at 2Y-FU. In the FLDS group, there was a statistically significant correlation between the preoperative CSCA and change in COMI score preoperatively to 2Y-FU (P<0.001). The association was retained in multiple regression analysis controlling for confounders. A one-degree increase in CSCA was associated with a 0.35-point worse COMI score at 2Y-FU (P=0.003). CONCLUSION: Treatment of far lateral nerve root compression showed overall good patient reported outcome, but with less improvement with advanced coronal segmental angulation. Modified approaches and techniques might be preferable for the level L5/S1.

Automatic Calculation of Cervical Spine Parameters Using Deep Learning: Development and Validation on an External Dataset.

STUDY DESIGN: Retrospective data analysis. OBJECTIVES: This study aims to develop a deep learning model for the automatic calculation of some important spine parameters from lateral cervical radiographs. METHODS: We collected two datasets from two different institutions. The first dataset of 1498 images was used to train and optimize the model to find the best hyperparameters while the second dataset of 79 images was used as an external validation set to evaluate the robustness and generalizability of our model. The performance of the model was assessed by calculating the median absolute errors between the model prediction and the ground truth for the following parameters: T1 slope, C7 slope, C2-C7 angle, C2-C6 angle, Sagittal Vertical Axis (SVA), C0-C2, Redlund-Johnell distance (RJD), the cranial tilting (CT) and the craniocervical angle (CCA). RESULTS: Regarding the angles, we found median errors of 1.66° (SD 2.46°), 1.56° (1.95°), 2.46° (SD 2.55), 1.85° (SD 3.93°), 1.25° (SD 1.83°), .29° (SD .31°) and .67° (SD .77°) for T1 slope, C7 slope, C2-C7, C2-C6, C0-C2, CT, and CCA respectively. As concerns the distances, we found median errors of .55 mm (SD .47 mm) and .47 mm (.62 mm) for SVA and RJD respectively. CONCLUSIONS: In this work, we developed a model that was able to accurately predict cervical spine parameters from lateral cervical radiographs. In particular, the performances on the external validation set demonstrate the robustness and the high degree of generalizability of our model on images acquired in a different institution.

Evaluation of the Clinical and Radiographic Degenerative Spondylolisthesis (CARDS) classification system as a guide to surgical technique selection.

BACKGROUND CONTEXT: The role of fusion in degenerative spondylolisthesis (DS) is controversial. The Clinical and Radiographic Degenerative Spondylolisthesis (CARDS) classification system was developed to assist surgeons in surgical technique selection based on individual patient characteristics. This system has not been clinically validated as a guide to surgical technique selection. PURPOSE: The purpose of this study was to determine if outcomes vary with different surgical techniques across the CARDS categories. STUDY DESIGN/SETTING: Prospective cohort study performed at one Swiss and one American spine center. PATIENT SAMPLE: Five hundred eight patients with DS undergoing surgical treatment. OUTCOME MEASURES: Core Outcomes Measure Index (COMI) at 3 months and 12 months postoperatively. METHODS: Patients undergoing surgery for DS were enrolled at 2 institutions and classified according to the CARDS system using dynamic radiographs. The Core Outcome Measure Index (COMI) was completed preoperatively, and 3 and 12 months postoperatively. Surgical technique was classified as uninstrumented (decompression alone or decompression with uninstrumented fusion) or instrumented (decompression with pedicle screw instrumentation with or without interbody fusion). Unadjusted analyses and mixed effect models compared COMI scores between the two surgery technique groups (uninstrumented vs instrumented), stratified by CARDS category over time. Reoperation rates were also compared between the surgery technique groups stratified by CARDS category. Partial funding was given through NASS grant for clinical research. RESULTS: Five hundred five out of 508 patients enrolled in the study had sufficient data to be classified according to CARDS. Seven percent were classified as CARDS A, 28% as CARDS B, 48% as CARDS C, and 17% as CARDS D (CARDS A most "stable," CARDS D least "stable"). One hundred and thirty-three patients (26%) underwent decompression alone, 30 (6%) underwent decompression and uninstrumented fusion, 42 (8%) underwent decompression and posterolateral instrumented fusion, and 303 (60%) underwent decompression with posterolateral and interbody instrumented fusion. Patients in the least "stable" categories tended to be less likely to be treated with an uninstrumented technique (CARDS D 19% vs 32% for the other categories, p=.10). There were no significant differences in 3 or 12-month COMI scores between surgical technique groups stratified by CARDS category in the unadjusted or adjusted analyses. In the unadjusted analyses, there was a trend towards less improvement in 12-month COMI change score in the CARDS D patients in the uninstrumented group compared to the instrumented group (-2.7 vs -4.1, p=.10). Reoperation rates were not significantly different between the surgical technique groups stratified by CARDS category. CONCLUSIONS: In general, outcomes for uninstrumented and instrumented surgical techniques were similar across the CARDS categories. Surgeons likely took factors included in CARDS into account during surgical technique selection. This resulted in a low number of CARDS D (n=15) patients being treated with uninstrumented techniques, which limited the statistical power of this analysis. As such, this study does not validate CARDS as a useful classification system for surgical technique selection in DS.

Clinical and surgical results related to anterior-only multilevel cervical decompression and instrumented fusion for degenerative disease.

Introduction: Anterior-only multilevel cervical decompression and fusion surgery (AMCS) on 3-5-levels is challenging due to potential complications. Also, outcome predictors after AMCS are poorly understood. Research Question: We hypothesize that in patients with at most mild/moderate cervical kyphosis (CK) of the cervical spine, restoration of cervical lordosis (CL) positively influences clinical outcomes. Methods: Analysis of consecutive patients presenting with symptomatic degenerative cervical disease or non-union undergoing AMCS. We measured CL from C2 to C7, Cobb angle of fused levels (fusion angle, FA), C7-Slope, and sagittal vertical axis C2-7 (cSVA, stratified into ≤4cm∖>4cm). Patients with excellent outcome were grouped in BEST-outcomes and with moderate/poor outcomes in WORST-outcomes. Results: We included 244 patients. Fifty-four percent had 3-, 39% 4-level and 7% had 5-level fusion. At mean follow-up of 26 months, 41% of patients achieved BEST-outcome and 23% WORST-outcome. Complications and reoperation rates did not significantly differ. Non-union significantly influenced outcomes. The number of patients with non-union was significantly higher in patients with a preoperative cSVA>4cm (OR 13.1 (95%CI:1.8-96.8). Our model, based on the multivariable analysis with WORST-outcome as outcome variable showed a high accuracy (NPV=73%, PPV=77%, specificity=79%, sensitivity=71%). Discussion and Conclusion: In 3-5-level AMCS, improvement of FA and cSVA were independent predictors of clinical outcome. Improvement of CL positively influenced clinical outcomes and rates of non-union.

Does loss to follow-up lead to an overestimation of treatment success? Findings from a spine surgery registry of over 15,000 patients.

PURPOSE: Patient-reported outcome measures (PROMs) are integral to the assessment of treatment success, but loss to follow-up (attrition) may lead to bias in the results reported. We sought to evaluate the extent, nature and implications of attrition in a long-established, single-centre spine registry. METHODS: The registry contained the data of 15,264 consecutive spine surgery patients. PROMs included the Core Outcome Measures Index (COMI) and a rating of the Global Treatment Outcome (GTO) and Satisfaction with Care. Baseline characteristics associated with returning a 12-month PROM (= "responder") were analysed (logistic regression). The 3-month outcomes of 12-month responders versus 12-month non-responders were compared (ANOVA and Chi-square). RESULTS: In total, 14,758/15,264 (97%) patients (60 ± 17y; 46% men) had consented to the use of their registry data for research. Preoperative, 3-month post-operative and 12-month post-operative PROMs were returned by 91, 90 and 86%, respectively. Factors associated with being a 12-month responder included: greater age, born in the country of the study, no private/semi-private insurance, better baseline status (lower COMI score), fewer previous surgeries, less comorbidity and no perioperative medical complications. 12-month non-responders had shown significantly worse outcomes in their 3-month PROMs than had 12-month responders (respectively, 66% vs 80% good GTO ("treatment helped/helped a lot"); 77% vs 88% satisfied/very satisfied; and 49% vs 63% achieved MCIC on COMI). CONCLUSION: Although attrition in this cohort was relatively low, 12-month non-responders displayed distinctive characteristics and their early outcomes were significantly worse than those of 12-month responders. If loss to follow-up is not addressed, treatment success will likely be overestimated, with erroneously optimistic results being reported.