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.

Sagittal alignment of diverse mechanical complications following adult spinal deformity surgery.

PURPOSE: To compare the sagittal alignment of patients with diverse mechanical complications (MCs) following adult spinal deformity (ASD) surgery with that of patients without MCs. METHODS: A total of 371 patients who underwent ASD surgery were enrolled. The sagittal spinopelvic parameters were measured preoperatively and at the 6-month and last follow-up, and the global alignment and proportion (GAP) score was calculated. The subjects were divided into non-MC and MCs groups, and the MCs group was further divided into rod fracture (RF), screw breakage (SB), screw dislodgement (SD) and proximal junctional kyphosis (PJK) subgroups. RESULTS: Preoperatively, the RF group had greater thoracolumbar kyphosis (TLK) and relative upper lumbar lordosis (RULL); the SB group had the largest pelvic incidence (PI) and lumbar lordosis (LL); the SD group had the least global sagittal imbalance; and the PJK group had the highest thoracic kyphosis (TK), TLK and RULL. At the last follow-up, the RF and SB groups featured a large PI minus LL (PI-LL), while the PJK group featured a prominent TK; all the MCs subgroups had sagittal malalignment and a higher GAP score, and the SB group had the most severe cases. Logistic regressions showed that the relative spinopelvic alignment (RSA) score was correlated with RF, SB and SD, while the RSA and age scores were associated with PJK. CONCLUSION: Each patient with MCs had individual characteristics in the sagittal plane following ASD surgery, which may be helpful to understand the pathophysiology of poor sagittal alignment with its subsequent MCs and guide an eventual revision strategy.

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

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

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.

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.

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.

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.

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.

Does the use of postoperative brace help preventing mechanical complications following adult deformity surgery?

PURPOSE: There is scarce information regarding the effectiveness of postoperative braces in decreasing mechanical complications and reinterventions following adult deformity surgery. METHODS: Retrospective matched cohort study from a prospective adult deformity multicenter database. We selected operated patients, fused to the pelvis, > 6 instrumented levels, and minimum 2 year follow-up. Three hundred and eighty patients were separated into two groups (Brace-3 months TLSO-vs No Brace) and then matched controlling for age, gender and frailty. We studied demographic, intraoperative, and postoperative spinopelvic parameters. Both groups were compared regarding complications and reinterventions in the first 2 postoperative years, using univariate and multivariate logistic regression analysis. RESULTS: We finally analyzed 359 matched patients, mean age of 65.3 ± 8.9 years, frailty-index (0.43 ± 0.15), and mostly females (84%). 224 patients wore a postoperative brace (B) and 135 didn't (NoB). They showed no difference in intraoperative variables and postoperative spinopelvic alignment. They differed (P < 0.05) in: Pelvic incidence (B:58° ± 13 vs NoB:54.5° ± 13); BMI (B:25.8 ± 4 vs NoB:27.4 ± 5); upper instrumented vertebra (B:81.7% T8-L1 vs NoB:72.6% T8-L1), and the use of multiple rods (B:47.3% vs NoB:18.5%). Univariate analysis showed a higher rate of mechanical complications and reinterventions when not using a brace. As well as higher NRS-back and leg pain at 6 weeks. However, multivariate analysis selected the use of multiple rods as the only independent factor protecting against mechanical complications (OR: 0.38; CI 95% 0.22-0.64) and reinterventions (OR: 0.41; CI 95% 0.216-0.783). CONCLUSION: After controlling for potential confounders, our study could not identify the protective effect of postoperative braces preventing mechanical complications and reinterventions in the first two postoperative years.

Revision surgery following long lumbopelvic constructs for adult spinal deformity: prospective experience from two dedicated databases.

PURPOSE: Pan Lumbar Arthodesis (PLA) are often required for Adult Spinal Deformity (ASD) correction, reducing significantly the compensatory capacity in case of postoperative sagittal malalignment. Few papers have investigated outcomes and complications in this vulnerable subset of patients. The objective of this study was to assess revision surgery rate for PLA in ASD, its risk factors and impact on clinical outcomes. METHODS: Retrospective multicenter review of prospective ASD data from 7 hospitals covering Europe and Asia. ASD patients included in two prospective databases having a posterior instrumentation spanning the whole lumbar region with more than 2-years of follow-up were reviewed. Demographic, surgical, radiographic parameters and Health-Related Quality of Life (HRQoL) scores were analyzed. Univariate and multivariate regression models analyzed risk factors for revision surgery as well as surgical outcomes. Patients with Early versus Late and PJK versus Non-PJK mechanical complications were also compared. RESULTS: Out of 1359 ASD patients included in the database 589 (43%) had a PLA and 357 reached 2-years mark. They were analyzed and compared to non-PLA patients. Average age was 67 and 82% were females. 100 Patients (28.1%) needed 114 revision surgeries (75.4% for mechanical failures). Revised patients were more likely to have a nerve system disorder, higher BMI and worst immediate postoperative alignment (as measured by GAP Parameters). These risk factors were also associated with earlier mechanical complications and PJK. Deformity and HRQoL parameters were comparable at baseline. Non-revised patients had significantly better clinical outcomes at 2-years (SRS 22 scores, ODI, Back pain). Multivariate analysis could identify nerve system disorder (OR 4.8; CI 1.8-12.6; p = 0.001), postoperative sagittal alignment (GAP Score) and high BMI (OR 1.07; CI 1.01-1.13; p = 0.004) as independent risk factors for revisions. CONCLUSIONS: Revision surgery due to mechanical failures is relatively common after PLA leading to worse clinical outcomes. Prevention strategies should focus on individualized restoration of sagittal alignment and better weight control to decrease stress on these rigid constructs in non-compliant spines. Nerve system disorders independently increase revision risk in PLA. LEVEL OF EVIDENCE II: Prognosis.

Sagittal realignment: surgical restoration of the global alignment and proportion score parameters: a subgroup analysis. What are the consequences of failing to realign?

INTRODUCTION: The Global Alignment and Proportion (GAP) score incorporates three domains directly modified with surgery (relative pelvic version-RPV, relative lumbar lordosis-RLL, lumbar distribution index-LDI) and one indirectly restored (relative spinopelvic alignment-RSA). We analyzed our surgical realignment performance and the consequences of domain-specific realignment failure on mechanical complications and PROMs. MATERIALS AND METHODS: From an adult spinal deformity prospective multicenter database, we selected patients: fused to pelvis, upper instrumented vertebra at or above L1, and 2 years of follow-up. Descriptive, univariate and multivariate analyses were employed. RESULTS: The sample included 333 patients. RLL-6w showed the highest success rate (58.3% aligned), but 16.5% of patients were classified in the "Severe hypolordosis" and "Hyperlordosis" subgroups. RPV-6w was the most challenging to realign, with 51.6% moderate or severe retroversion. Regarding RSA-6w, 21.9% had severe positive malalignment. Correct alignment of RPV-6w (p = 0.025) and RSA-6w (p = 0.002) proved to be protective factors against the development of mechanical complications. Severe pelvic retroversion (p = 0.026) and severe positive malalignment (p = 0.007) were risk factors for mechanical complications. RSA-6w "Severe positive malalignment" was associated with less improvement in PROMs: ∆ODI (8.83 vs 17.2; p = 0.011), ∆SRS-22 total (0.54 vs 0.87; p = 0.007), and ∆SF-36PCS (3.47 vs 7.76; p = 0.04); MCID for ODI (37.0 vs 55.5%; p = 0.023), and SRS-22 (40.8 vs 60.1%; p = 0.015); and PASS for ODI (17.6 vs 31.7%; p = 0.047). CONCLUSIONS: RPV was the most underperformed modifiable parameter. Severe pelvic retroversion and severe positive malalignment influenced the occurrence of mechanical complications. Severe positive malalignment affected PROMs improvement.

Relationship between pelvic incidence-adjusted relative spinopelvic parameters, global sagittal alignment and lower extremity compensations.

PURPOSE: In response to sagittal malalignment, compensatory spinal and lower extremity mechanisms are recruited. Thoracolumbar realignment surgery has been shown to yield reciprocal changes in these compensations. Thus, whole-body radiographic assessment has come to the fore. This study aimed to evaluate the relationship between spinopelvic parameters and lower extremity compensation angles and to examine their coupled change with deformity correction. METHODS: This was a multicenter retrospective analysis of patients who had ≥ 4 levels posterior fusion, whole-body radiographs, and ≥ 2 years follow-up. Relative Pelvic Version (RPV), Relative Lumbar Lordosis (RLL), Relative Spinopelvic Alignment (RSA), Femoral Obliquity Angle (FOA), Knee Flexion Angle (KFA) and Global Sagittal Axis (GSA) were measured preoperatively and 6 week postoperatively. Kruskal-Wallis tests were performed to assess the relation of relative spinopelvic parameters to global sagittal alignment and lower extremity compensation angles. Spearman's correlations were performed to assess correlations of pre-to-postoperative changes. RESULTS: 193 patients (156F, 37 M) were included. The mean age was 57.2 ± 16.6 years. The mean follow-up duration was 50.6 (24-90) months. On average, 10.3 ± 3.8 levels were fused. Among the cohort, 124 (64.2%) had a sacral or sacroiliac fixation, and 43 (22.3%) had 3-column osteotomies. Preoperative FOA, KFA and GSA significantly differed between RPV, RLL and RSA categories. Significant weak-to-strong correlations were observed between spinopelvic parameters, global sagittal alignment and lower extremity compensation angles (rho range: - 0.351 to 0.767). CONCLUSIONS: PI-adjusted relative spinopelvic parameters significantly correlated with measurements of the lower extremity compensation. Postoperative changes in RPV, RLL and RSA reflected changes in FOA, KFA and GSA. These measurements may serve as a valuable proxy for surgical planning when whole-body imaging is not available.

Association between sagittal alignment and loads at the adjacent segment in the fused spine: a combined clinical and musculoskeletal modeling study of 205 patients with adult spinal deformity.

PURPOSE: Sagittal malalignment is a risk factor for mechanical complications after surgery for adult spinal deformity (ASD). Spinal loads, modulated by sagittal alignment, may explain this relationship. The aims of this study were to investigate the relationships between: (1) postoperative changes in loads at the proximal segment and realignment, and (2) absolute postoperative loads and postoperative alignment measures. METHODS: A previously validated musculoskeletal model of the whole spine was applied to study a clinical sample of 205 patients with ASD. Based on clinical and radiographic data, pre-and postoperative patient-specific alignments were simulated to predict loads at the proximal segment adjacent to the spinal fusion. RESULTS: Weak-to-moderate associations were found between pre-to-postop changes in lumbar lordosis, LL (r = - 0.23, r = - 0.43; p < 0.001), global tilt, GT (r = 0.26, r = 0.38; p < 0.001) and the Global Alignment and Proportion score, GAP (r = 0.26, r = 0.37; p < 0.001), and changes in compressive and shear forces at the proximal segment. GAP score parameters, thoracic kyphosis measurements and the slope of upper instrumented vertebra were associated with changes in shear. In patients with T10-pelvis fusion, moderate-to-strong associations were found between postoperative sagittal alignment measures and compressive and shear loads, with GT showing the strongest correlations (r = 0.75, r = 0.73, p < 0.001). CONCLUSIONS: Spinal loads were estimated for patient-specific full spinal alignment profiles in a large cohort of patients with ASD pre-and postoperatively. Loads on the proximal segments were greater in association with sagittal malalignment and malorientation of proximal vertebra. Future work should explore whether they provide a causative mechanism explaining the associated risk of proximal junction complications.

Combined anterior-posterior versus all-posterior approaches for adult spinal deformity correction: a matched control study.

PURPOSE: Anterior approaches are gaining popularity for adult spinal deformity (ASD) surgeries especially with the introduction of hyperlordotic cages and improvement in MIS techniques. Combined Approaches provide powerful segmental sagittal correction potential and increase the surface area available for fusion in ASD surgery, both of which would improve overall. This is the first study directly comparing surgical outcomes between combined anterior-posterior approaches and all-posterior approach in a matched ASD population. METHODS: This is a retrospective matched control cohort analysis with substitution using a multicenter prospectively collected ASD data of patients with > 2 year FU. Matching criteria include: age, American Society of Anesthesiologists Score, Lumbar Cobb angle, sagittal deformity (Global tilt) and ODI. RESULTS: In total, 1024 ASD patients were available for analysis. 29 Combined Approaches patients met inclusion criteria, and only 22 could be matched (1:2 ratio). Preoperative non-matched demographical, clinical, surgical and radiological parameters were comparable between both groups. Combined approaches had longer surgeries (548 mns vs 283) with more blood loss (2850 ml vs 1471) and needed longer ICU stays (74 h vs 27). Despite added morbidity, they had comparable complication rates but with significantly less readmissions (9.1% vs 38.1%) and reoperations (18.2% vs 43.2%) at 2 years. Combined Approaches achieved more individualised and harmonious deformity correction initially. At the 2 years control, Combined Approaches patients reported better outcomes as measured by COMI and SRS scores. This trend was maintained at 3 years. CONCLUSION: Despite an increased initial surgical invasiveness, combined approaches seem to achieve more harmonious correction with superior sagittal deformity control; they need fewer revisions and have improved long-term functional outcomes when compared to all-posterior approaches for ASD deformity correction.

Compensatory mechanisms recruited against proximal junctional kyphosis by patients instrumented from the thoracolumbar junction to the iliac.

PURPOSE: The compensatory mechanisms recruited by un-instrumented patients against sagittal imbalance are well documented. However, there is a lack of information regarding instrumented patients. MATERIAL AND METHODS: We performed a retrospective analysis of data collected prospectively in a multicenter adult spinal deformity database. We included patients suffering PJK/PJF after (T8-L2) to iliac instrumentation with minimum two-year follow-up. We measured quantitative sagittal spinopelvic and qualitative sagittal distribution parameters in the immediate postoperative period (6w) and at the time of PJK/PJF appearance. We analyzed how these parameters changed comparing these two time points with univariate and multivariate logistic regression analyses. RESULTS: A total of 69 patients were included. Two different patterns at PJK/PJF were found: 36 patients activated compensation (defined as an increase in pelvic retroversion (ΔRPV > 5º), and 33 did not (ΔRPV < 5º). The difference in behavior relied mostly on the amount of not surgically restored pelvic rotation at 6w (OR: 0.6; CI95%: 0.4-9.2; P = 0.017). Non-compensators had less rotation reserve (PTx100/PI = 33.9% vs 47.8%;P < 0.001) associated with worse 6w relative pelvic version and lower lumbar arc restoration, worse 6w relative sagittal alignment and GAP-score, compared with compensators (P < 0.001). Compensators' response was based on pelvic retroversion, causing lower lumbar arc decrease, lumbar apex caudal migration, and upper lumbar arc posterior inclination. Despite compensation, a thoracic kyphosis increase in both upper and lower arches gradually evolved into a PJK/PJF. Non-compensators did not react to PJK/PJF, which forced them into kyphosis from the lumbar apex and extending cranially, mainly throughout the upper thoracic arc. CONCLUSIONS: In patients fused from the TL junction to the iliac, those having greater postoperative pelvic rotation reserve showed greater capacity to recruit compensatory mechanisms against PJK/PJF.

Surgeons' risk perception in ASD surgery: The value of objective risk assessment on decision making and patient counselling.

BACKGROUND: Surgeons often rely on their intuition, experience and published data for surgical decision making and informed consent. Literature provides average values that do not allow for individualized assessments. Accurate validated machine learning (ML) risk calculators for adult spinal deformity (ASD) patients, based on 10 year multicentric prospective data, are currently available. The objective of this study is to assess surgeon ASD risk perception and compare it to validated risk calculator estimates. METHODS: Nine ASD complete (demographics, HRQL, radiology, surgical plan) preoperative cases were distributed online to 100 surgeons from 22 countries. Surgeons were asked to determine the risk of major complications and reoperations at 72 h, 90 d and 2 years postop, using a 0-100% risk scale. The same preoperative parameters circulated to surgeons were used to obtain ML risk calculator estimates. Concordance between surgeons' responses was analyzed using intraclass correlation coefficients (ICC) (poor < 0.5/excellent > 0.85). Distance between surgeons' and risk calculator predictions was assessed using the mean index of agreement (MIA) (poor < 0.5/excellent > 0.85). RESULTS: Thirty-nine surgeons (74.4% with > 10 years' experience), from 12 countries answered the survey. Surgeons' risk perception concordance was very low and heterogeneous. ICC ranged from 0.104 (reintervention risk at 72 h) to 0.316 (reintervention risk at 2 years). Distance between calculator and surgeon prediction was very large. MIA ranged from 0.122 to 0.416. Surgeons tended to overestimate the risk of major complications and reintervention in the first 72 h and underestimated the same risks at 2 years postop. CONCLUSIONS: This study shows that expert surgeon ASD risk perception is heterogeneous and highly discordant. Available validated ML ASD risk calculators can enable surgeons to provide more accurate and objective prognosis to adjust patient expectations, in real time, at the point of care.

Revision surgery for incomplete resection or recurrence of cervical spine chordoma: a consecutive case series of 24 patients.

PURPOSE: Chordomas are rare tumors with an annual incidence of approximately one per million. Chordomas rarely metastasize but show a high local recurrence rate. Therefore, these patients present a major clinical challenge, and there is a paucity of the literature regarding the outcome after revision surgery of cervical spine chordomas. Available studies suggest a significantly worse outcome in revision scenarios. The purpose of this study is to analyze the survival rate, and complications of patients that underwent revision surgery for local recurrence or incomplete resection of chordoma at the craniocervical junction or at the cervical spine. METHODS: 24 consecutive patients that underwent revision surgery for cervical spine chordoma remnants or recurrence at a single center were reviewed retrospectively. We analyzed patient-specific surgical treatment strategies, complications, and outcome. Kaplan-Meier estimator was used to analyze five-year overall survival. RESULTS: Gross total resection was achieved in 17 cases. Seven patients developed dehiscence of the pharyngeal wall, being the most common long-term complication. No instability was observed. Postoperatively, four patients received proton beam radiotherapy and 12 patients had combined photon and proton beam radiotherapy. The five-year overall survival rate was 72.6%. CONCLUSION: With thorough preoperative planning, appropriate surgical techniques, and the addition of adjuvant radiotherapy, results similar to those in primary surgery can be achieved.

The dynamics of satisfaction in surgical and non-surgical adult spinal deformity patients.

PURPOSE: For adult spinal deformity (ASD) patients receiving operative (op) and non-operative (non-op) treatment, the relationship between HRQoL measures, complications and self-reported satisfaction remains unclear. The objective of this analysis is to study nonlinear association dynamics between ASD patient satisfaction, HRQoL, and complications over a two-year follow-up period. METHODS: From a prospective multicenter international adult spinal deformity database, all patients with 2-year follow-up data on satisfaction (21st question of SRS-22r) were identified and included. A total of 12 LOESS (local polynomial fit) regressions were performed between patient satisfaction (SRS22 item 21) and HRQoL measures (ODI, SF36PCS and SRS22 subtotal) interacting with surgery at baseline, 6 months and 1 and 2 years of follow-up. RESULTS: A total of 856 patients (527 op and 329 non-op) were included. At baseline, satisfaction was lower for patients scheduled for surgery even when HRQL was similar to those elected for conservative treatment. The nonlinear correlations showed that for similar PROMs, op patients reached higher satisfaction levels during follow-up, especially at six months. In fact, at six months operated patients with a deterioration of their initial PROMs had some improvement in their satisfaction, which could not be further observed at the end of follow-up. CONCLUSIONS: Satisfaction does not correlate well with other PROMs, and it might be subject to other external factors not directly related to treatment. Even if patient satisfaction is important in evaluating well-being and patient's experience with medical care, it should not be considered as an isolated proxy to measure quality of treatment.

Effect of lumbar pedicle subtraction osteotomy level on lordosis distribution and shape.

PURPOSE: Little is known about the qualitative results (postoperative upper/lower lumbar arches distribution and lumbar apex or inflection point positioning) of lumbar pedicle subtraction osteotomies (L-PSO) depending on the level of L-PSO. METHODS: We conducted a retrospective analysis of prospectively collected data of adult deformity patients undergoing single-level L-PSO. We analyzed several variables in preoperative and postoperative sagittal radiographs: L-PSO level, Roussouly classification (R-type), inflection point (InfP), lumbar apex (LApex), spinopelvic parameters, lordosis distribution index (LDI = L4-S1/L1-S1), and number of levels in the lordosis (NVL). Comparisons between PSO levels were performed to determine lordosis distribution and sagittal shape using ANOVA test and Chi-squared statistics. RESULTS: A total of 126 patients were included in this study. L5-PSO mainly increased the lower lumbar arch, thereby increasing LDI. L4 increased upper/lower arches similarly. PSOs at and above L3 increased the upper lumbar arch, thereby decreasing LDI (P < 0.001). L4-PSO added 1 vertebra into the lordosis (NVL = + 1.2 ± 2.2). PSOs above L3 added 2 vertebrae into the lordosis (NVL = + 2.3 ± 1.4). Overall P = 0.007. PSOs above L4 shifted the LApex cranially in 70% of the cases (mean 1.12 levels) and the InfP in 85% of the cases (mean 2.4 levels). L5-PSO shifted the LApex caudally in 70% of the cases (mean - 1.1 levels) and the InfP in 50% of the cases (mean - 1.6 levels). Overall P < 0.006. The L-PSO level was not associated with a specific Roussouly-type P > 0.05. CONCLUSIONS: The level of L-PSO influenced upper/lower lumbar arches distribution, and lumbar apex and inflection point positioning. The correct level should be chosen based on the individual assessment of each patient.

Restoring the ideal Roussouly sagittal profile in adult scoliosis surgery decreases the risk of mechanical complications.

PURPOSE: There are still no data proving whether restoring the ideal sagittal profile (according to Roussouly classification) in adult scoliosis (AS) patients leads to any additional benefit, especially regarding mechanical complications. METHODS: Retrospective analysis of operated AS patients recorded in a prospective multicenter database. Demographic and radiographic (preoperative and 6-week postoperative) data were analyzed. Patients with and without mechanical complications were compared looking especially at the surgical restoration of the ideal (based on Pelvic Incidence) sagittal profile. Univariate and multivariate analysis was performed to identify causes of mechanical complications at 2-year minimum follow-up. RESULTS: Ninty-six AS patients were analyzed. Thirty-nine patients suffered a mechanical complication (18 PJK, 11 pseudoarthrosis, 10 screw pull-out), and 57 patients had no mechanical complications. Postoperatively, 72% of patients not matching the ideal Roussouly-type suffered mechanical complications compared to 15% of matched patients (P < 0.001). Univariate analysis showed that older patients 64.9 ± 13 versus 40.7 ± 15.6 years (P < 0.001), higher postoperative Global Tilt (27° vs. 14.7°) and Pelvic Tilt (25° vs. 16°) (P < 0.001), upper instrumented vertebra at the thoracolumbar junction (62% vs. 21%) (P < 0.001), fixation to the Iliac (76% vs. 6%) (P < 0.001), and postoperative Roussouly-type mismatch (72% vs. 15%) (P < 0.001) significantly increased the rate of mechanical complications. Multivariate logistic regression analysis selected: postoperative Roussouly-type mismatch (OR = 41.9; 95%CI = 5.5-315.7; P < 0.001), iliac instrumentation (OR = 19.4; 95%CI = 2.6-142.5; P = 0.004), and age (OR = 1.1; 95%CI = 1.02-1.16; P = 0.004), as the most important variables. CONCLUSIONS: Adult scoliosis surgery should restore the ideal Roussouly sagittal profile to decrease the rate of mechanical complications, especially in patients older than 65, instrumented to the pelvis. These slides can be retrieved under Electronic Supplementary Material.