Christopher I. Shaffrey

BACKGROUND AND OBJECTIVES: The unfused lumbar curve (ULC) distal to a thoracolumbar fusion may respond differently in pediatric vs adult scoliosis patients because of age-related differences in flexibility and compensatory capacity. However, no previous study has directly compared age-related postoperative ULC behavior between these cohorts to better understand differences in coronal balance restoration. METHODS: Four hundred fifty-one patients undergoing thoracolumbar fusion for idiopathic scoliosis with a thoracic upper instrumented vertebra and lower instrumented vertebra between L1-L4 were included: pediatric aged 8 to 17 years (n = 346), and adults aged 18 years and older (n = 105). Pediatric ULC (pULC) and adult ULC (aULC) were defined as coronal Cobb angle between lower instrumented vertebra and S1, if >10°. Radiographic parameters and outcomes (Scoliosis Research Society-22, mechanical complications) were assessed preoperatively, 6 weeks (early), and 2 years (late). Global coronal malalignment (GCM) was central sacral vertical line distance. RESULTS: Pediatric (14.9 ± 2.2 yo) and adult (34.5 ± 15.1 yo) patients had similar major curve magnitude and correction (pediatric: preop 57.7° ± 12.8° vs 55.3° ± 17.6°, 6-week 20.3° ± 7.5° vs 19.9° ± 12.4°; P > .2). Preoperative pULCs were larger (22.8° ± 6.5° vs 19.9° ± 7.3°; P < .001) and experienced greater correction at 6 weeks (Δ18.2° vs Δ12.9°; P < .001). pULC and GCM changed significantly at 6 weeks and remained stable at 2 years, whereas adult GCM changed over 2 years ( P < .001). Age was associated with lower preoperative ULC and higher residual ULC at 6 weeks and 2 years (all P < .001). pULC remodeled directionally to improve GCM early postoperatively ( P = .03), whereas aULCs remodeled to improve GCM late postoperatively ( P = .037). Larger residual pULC was associated with lower Scoliosis Research Society-22 pain and function; residual pULC and aULC were not associated with mechanical complications ( P = .21) or reoperations ( P = .06). There were few caudal extension fusions (3 adults, 0 children) in this cohort. CONCLUSION: Pediatric patients experience greater magnitude correction of the ULC compared with adults after thoracolumbar fusion for scoliosis. ULC remodels to improve GCM early in children and late in adults. Residual ULC magnitude was not associated with mechanical complications.

BACKGROUND AND OBJECTIVES: Decisional regret (DR) measures perception of an event relative to one's own expectations, for example, the choice to undergo or perform adult spinal deformity (ASD) surgery. It is unclear how patient and surgeon DR evolves after ASD surgery and what drives asymmetry. METHODS: Nine hundred and twelve patients who underwent ASD surgery and their surgeons were asked at 6 weeks, 1 year, and 2 years postoperatively: “Would you have/perform the same surgery again?” (patient/surgeon SS). Responses were on a Likert scale (5 = Definitely yes, 4 = Probably yes, 3 = Unsure, 2 = Probably no, 1 = Definitely no). Patient-surgeon disagreement (D) was quantified as D = patient SS–surgeon SS; distributional symmetry was tested using the Wilcoxon signed-rank test. Multivariable ordinal regression evaluated factors associated with SS and disagreement. RESULTS: At 6 weeks, DR was low for both patients and surgeons. Over 2 years, patient same-surgery (SS) scores improved (odds ratios [OR] = 1.35-1.51, P = .02), whereas surgeon SS score remained stable ( P > .1). Patient-surgeon disagreement was small (P < .001) and 1 year (D = −0.19, P = .002), resolving by 2 years ( P = .09). Baseline disability was associated with greater early surgeon regret relative to patients (OR = 0.43–0.53, P < .02), whereas baseline opioid use was associated with greater long-term patient regret (OR = 1.77, P = .04). After revision surgery, patients were more likely to report improved SS score (39.7% vs 18.5%, P < .001), whereas surgeons were more likely to report worsening SS score (17.2% vs 11.1%, P = .003). Early patient SS score was associated with 2-year ODI (r = −0.241, P < .001) and Scoliosis Research Society-22 total score (r = 0.339, P < .001) and outperformed Scoliosis Research Society-22 satisfaction in predicting long-term outcomes ( P < .05). CONCLUSION: Patients and surgeons have low DR after ASD surgery, and when there is asymmetry, it is small and within the 1-year postoperative period. After revision, patients are more likely to have decreased regret, whereas surgeon regret does not improve. These findings have implications for patient counseling and expectations.

BACKGROUND AND OBJECTIVES: Minimally clinically important difference (MCID) defines the smallest difference in patient-reported outcomes (PROs) required for a level of clinical improvement. The hypothesis of this study is that at least one of the MCID thresholds in this study will provide appropriate MCID thresholds for the PROs in grade 2 spondylolisthesis. METHODS: This study used the Grade 2 Spondylolisthesis module of the Quality Outcomes Database Spine CORe ^® Study Group, which included 328 patients from 14 institutions. PROs collected include Oswestry Disability Index (ODI), Numeric Rating Scale (NRS) for back pain and leg pain, and European Quality of Life-5 Dimensions (EQ-5D). Seven MCID thresholds were calculated with North American Spine Society satisfaction scale as the anchor. Each method was evaluated using area under the curve, reflecting the ability to predict satisfaction. RESULTS: There were 328 patients with ≥80% 5-year follow-up. The optimal percentage cutoff method generally demonstrated the highest predictive accuracy for defining MCID in ODI, NRS back pain, and NRS leg pain, whereas the optimal numeric cutoff method generally demonstrated the highest predictive accuracy for EQ-5D. For ODI, 2-year optimal percentage cutoff was 30.4% and 5-year optimal percentage cutoff was 38.1%. For NRS back pain, 2-year optimal percentage cutoff was 75.0% and 5-year optimal percentage cutoff was 42.9%. For NRS leg pain, 2-year optimal percentage cutoff was 62.5% and 5-year optimal percentage cutoff was 66.6%. For EQ-5D, the optimal numeric cutoffs were 0.293 at 2 years and 0.128 at 5 years. CONCLUSION: Using satisfaction as an anchor, this study identified the optimal percentage cutoff as the most appropriate method for determining MCID in ODI and NRS pain scores, while the optimal numeric cutoff was most appropriate for EQ-5D in grade 2 spondylolisthesis. These findings provide reference definitions for evaluating postoperative improvement in this patient population.

BACKGROUND AND OBJECTIVES: Postoperative thoracolumbar (TL) realignment in patients with adult spinal deformity (ASD) may induce cervical spine (CS) decompensation. This study identifies predictors of CS decompensation after TL surgery and defines a baseline CS-alignment threshold based on C2-pelvic angle (C2-PA) for CS inclusion in the TL construct. METHODS: Patients with ASD undergoing TL fusion to the sacrum with an upper instrumented vertebrae at T2 or below and available baseline radiographs and patient-reported outcome measures (PROMs) were included. CS decompensation was defined as CS surgery or >2 SD above the mean in C2-PA, cervical sagittal vertical axis (cSVA), or T1-slope cervical lordosis (TS-CL) at the studied postoperative time point. RESULTS: One thousand one hundred ninety patients were included; 166 (13.9%) had CS decompensation after TL surgery, including 24 (2.0%) requiring CS extension. CS decompensation was identified in 81 patients (6.8%) at 6 weeks (4 (0.3%) extensions), 13 (1.2%) at 6 months (2 (0.2%)), 43 (3.9%) at 1 year (7 (0.6%)), and 29 (2.8%) at 2 years (11 (0.9%)). Patients with CS decompensation at 6 months showed worse global and CS alignment at 6 weeks (lumbar lordosis: 53.6 vs 46.3; cSVA: 30.5 vs 38.5; P < .05). CS decompensation at 1 year was associated with worse PROMs (physical component score: 39.0 vs 35.4; Scoliosis research society score: 3.6 vs 3.3; P < .05). CS decompensation at 2 years was associated with worse CS alignment at 1 year (TS-CL: 20.8 vs 28.6; cSVA: 31.1 vs 37.8) and worse PROMs at 2 years. Higher baseline C2-PA was associated with shorter time to CS decompensation. Cox modeling identified baseline C2-PA (hazard ratio [HR] 1.05, 95% CI, 1.03-1.06), TS-CL (HR 1.05, 95% CI, 1.03-1.06), surgical invasiveness (HR 0.99, 95% CI, 0.98-0.99), and upper thoracic instrumentation (HR 2.9, 95% CI, 1.8-4.7) as predictors of CS decompensation, with a C2-PA threshold of 26.2°. CONCLUSION: Two years after TL ASD surgery, 13.9% had CS decompensation, with 14% requiring CS extension. Baseline CS alignment independently predicted CS decompensation. Patients with preoperative C2-PA >26.2° may benefit from CS inclusion in the TL construct after external validation of this threshold by future research.

Study Design.: Retrospective analysis of a prospective multicenter operative cervical deformity (CD) database. Objective.: To determine whether T1 slope (T1S) and C2 slope (C2S) together identify distinct CD phenotypes: cervical-only versus global sagittal deformity, and to compare surgical invasiveness, radiographic correction, and patient-reported outcomes. Summary of Background Data.: T1S and C2S mark cervical malalignment, and elevated T1S has been linked to global sagittal malalignment. Combining them may distinguish CD-only from global deformity on cervical imaging alone. Methods.: Operative CD patients with ≥2 years follow-up and preoperative C2S >30° were stratified by T1S into low T1S–high C2S (LTHC; ≤30°) and high T1S–high C2S (HTHC; >30°). Multivariable regression assessed group effect on 2-year NDI change, adjusted for age, sex, baseline NDI, and posterior levels fused. NDI MCID was set a priori at ≥7 points per the ISSG threshold. Results.: Ninety-two patients met criteria (31 LTHC, 61 HTHC). HTHC patients were older (64.7 vs. 60.0 years; P =0.035) with higher Charlson index ( P =0.022). Preoperatively, HTHC had greater thoracic kyphosis, TPA, cSVA, PI–LL mismatch, and C7 SVA (all P ≤0.010). HTHC underwent more extensive surgery: more posterior levels fused (10.3 vs. 6.7), more circumferential fusions (66.7% vs. 38.7%), and more caudal LIV (T7 vs. T3) (all P P =0.906), but 2-year NDI improvement was smaller in HTHC (−6.2 vs. −14.6 points; P =0.013), and fewer achieved MCID (45.9% vs. 71.0%; P =0.022). HTHC remained an independent predictor of smaller improvement (β=+7.4; P =0.020). Reoperation, DJK, and complication rates did not differ. Conclusions.: Among CD patients with elevated C2S, additional elevated T1S identifies a global-deformity phenotype requiring more invasive correction and showing smaller 2-year patient-reported improvement despite comparable complications. T1S and C2S, measurable on cervical imaging alone, screen for which CD patients warrant full-spine imaging. Level of Evidence.: III (retrospective analysis of prospectively collected multicenter data).

Introduction Predicting post-operative changes in thoracic kyphosis (TK) remains challenging in adult spinal deformity (ASD) surgery. This study aimed to quantify both iatrogenic and reciprocal changes in TK following lumbar correction and assess their maintenance at 2-year follow-up. Methods A retrospective analysis was performed on 356 ASD patients treated with posterior instrumentation from T9–11 to the pelvis, with a minimum 2-year follow-up. TK values were compared with normative data. Multivariate analysis identified thoracolumbar parameters associated with reciprocal thoracic changes and proximal failure. Results Pre-op TK (median 34°) was normal for 59.8% and hypokyphotic for 39.0% of patients. At 6 weeks, 79.1% of initially hypokyphotic patients normalized, while 11.3% of normokyphotic patients deteriorated. Postoperative TK increase correlated with lumbar lordosis gain (p15°, and 9.6% required proximal extension for junctional issues—defined collectively as “thoracic failures” (17.4%). Independent predictors of failure included advanced age (OR 3.6), more proximal lumbar correction (OR 1.9), and pronounced early mid-thoracic kyphosis (OR 2.3). Conclusion In ASD surgery with Upper Instrumented Vertebra (UIV) between T9 and T11, changes in TK were largely proportional to lumbar correction, leading to normalization in most cases. However, age, the location of lumbar correction, and early post-operative thoracic shape independently predicted thoracic failure, highlighting the need for tailored alignment strategies.

Study Design.: Retrospective analysis of a multicenter series of deformity patients undergoing thoracolumbar instrumentation to the pelvis. Objective.: Introduce the C2 coronal angle (C2C) as a novel metric, assess its association with quality-of-life and neck-specific outcomes, and compare the strength of this association with the traditional linear C7–CSVL offset. Summary of Background Data.: While assessment of the sagittal plane incorporates vertebropelvic angles for surgical planning, angular coronal measurements have not been evaluated as predictors of patient-reported outcomes following adult spinal deformity (ASD) surgery. Methods.: Demographics, comorbidities, and radiographic parameters were collected preoperatively and at 2-year follow-up. Coronal angles were measured between CSVL and the center of the C2 body (C2C). Primary endpoints were patient‑reported outcomes at two years (SRS‑22, SF‑36, NDI) and whether patients achieved the minimal clinically important difference (MCID). Univariable and multivariable regression models examined the relationship between C2C and PROMs. An ROC analysis with Youden’s Index identified optimal C2C thresholds for predicting NDI >20. Results.: Among 328 patients (mean age 64.0 years, 12.6 levels fused), postoperative absolute C2C was independently associated with PROMs. Each 1° increase in C2C was associated with decreased 2-yr SRS-Total ( P =0.014) and activity ( P =0.024), pain ( P =0.033), and mental health ( P =0.029) subdomains. Each 1° increase reduced odds of achieving NDI MCID by 34% (OR=0.66, P =0.022). ROC identified an optimal C2C threshold of 3.5°. Patients exceeding this had nearly twice the odds of neck disability (OR=1.90, P =0.049) and significantly lower SF-36 Physical Component ( P =0.004) and Physical Functioning ( P =0.011) scores. C2C was more strongly associated with SRS-Total than C7-CSVL (AIC=657 vs. 660; adj. R²=0.058 vs.0.048). Conclusions.: Achieving postoperative C2C ≤3.5° is independently associated with reduced neck disability and optimized quality of life after ASD surgery. C2C was more strongly associated with SRS-Total than C7-CSVL and could be considered as a complementary measure of coronal alignment.

Study Design.: Retrospective analysis of a multicenter complex adult spinal deformity (ASD) cohort. Objectives.: Develop a simplified, weighted, and modifiable ASD Frailty Index (o-ASD-FI) that incorporates modifiable health components. Background.: Though newer frailty indices have emerged, none specifically addresses complex ASD while incorporating modifiable health factors. Methods.: Miller’s ASD-FI variables were evaluated via Pearson bivariate correlation and multiple stepwise regression. Ten frailty and three modifiable health factors (depression, diabetes, and osteoporosis) were identified and regressed against mortality, extended length of stay (LOS > 8 d), revisions, and major complications. Coefficients were weighted using Johnson’s method to create the o-ASD-FI (range: 0 – 18). Frailty categories were defined as: not frail (P P P P <0.01. Conclusions.: The newly developed simplified, weighted, and optimizable ASD Frailty Index (o-ASD-FI) incorporates modifiable health components, providing a robust assessment of physiological status and potentially superior risk stratification compared with existing tools for both primary and revision complex spinal deformity surgery. Level of Evidence: III

Study Design: Retrospective analysis of patients from the prospective Quality Outcomes Database Spine CORe ^® Spondylolisthesis cohort to assess the prevalence of sleep dysfunction and factors associated with improved sleep after surgery. Objective: To characterize the prevalence of sleep disruption and identify factors associated with improved sleep among patients undergoing surgery for Meyerding grade I degenerative lumbar spondylolisthesis. Summary of Background Data: Improved sleep after surgery for lumbar spinal stenosis has been reported in several studies but not in patients with spondylolisthesis. Methods: A total of 608 patients from the prospective Quality Outcomes Database Spine CORe ^® Spondylolisthesis cohort were retrospectively analyzed. Patients were included in this study if they responded to the sleep subitem of the Oswestry Disability Index (ODI) at baseline and 24-month follow-up. The level of sleep dysfunction was assessed and compared at baseline and 24-month follow-up using univariable and multivariable statistics. Results: Overall, 526 of the 608 patients met the inclusion criteria. At baseline, 455 patients (86.5%) had sleep disruption. At 24 months or greater, 325 patients (71.4% of the 455 impaired) had improved sleep, with 184 patients (40.4%) reporting no disruption of sleep postoperatively. In multivariable analyses, improvement in sleep was predicted by a higher baseline ODI (OR=1.01, 95% CI: 1.001–1.01, P P =0.002) and higher ASA grade (OR=1.15, 95% CI: 1.02–1.30, P =0.03) in the 65 years or younger cohort, while minimally invasive techniques (OR=1.14, 95% CI: 1.01–1.30, P =0.04) were significant in the 65 years of age or older cohort. Conclusion: Most patients (86.5%) presenting for surgery for low-grade degenerative spondylolisthesis have impaired sleep. However, 24 months after surgery, over 70% of patients with baseline dysfunction reported improvements with 40.4% reporting no sleep dysfunction.

Aims: Proximal junctional kyphosis (PJK) remains a major complication after surgery for adult spinal deformity (ASD). While postoperative alignment is a recognized modifiable risk factor, objective methods for selecting the upper instrumented vertebra (UIV), a key modifiable factor, are lacking. We aimed to determine whether preoperative sagittal alignment, specifically cervicothoracic alignment, predicts the risk of PJK, and whether this risk can be mitigated by UIV selection, focusing on factors available at the time of surgical planning. Methods: From a multicentre, prospective ASD registry, we identified patients who had undergone fusion to the sacrum or pelvis and had an upper (T1–T5) or lower thoracic (T9–L1) UIV, with a two-year or more radiological follow-up, excluding those with a previous fusion over more than four levels. The primary outcome was PJK within two years. Multivariable logistic regression modelled the risk of PJK by UIV region, preoperative C2–T9 pelvic angle (PA), age, sex, and pelvic incidence, testing for interaction between UIV region and C2–T9 PA. Adjusted absolute risk reduction (ARR) and number needed to be exposed (NNEB) were calculated. Multivariable linear regression estimated two-year patient-reported outcome measures, adjusting for baseline scores, age, UIV, and PJK. Results: A total of 627 patients across 20 centres were included (median age 66 years (IQR 59 to 70); 483 (77%) female). The UIV was lower thoracic in 380 (61%) and upper thoracic in 247 (39%) patients. PJK occurred in 149 (39%) lower thoracic and 38 (15%) upper thoracic UIV patients. There was a significant interaction (p = 0.028) between preoperative C2–T9 PA and UIV region. At a preoperative C2–T9 PA of 14° (cohort median), an upper thoracic UIV had an adjusted ARR of 36% and NNEB was 2.8. Females had an adjusted odds ratio of 1.62 (95% CI 1.03 to 2.59; p = 0.042) for PJK. Conclusion: Worse preoperative sagittal malalignment, measured by C2–T9 PA, was associated with a higher risk of PJK and depended on UIV region. An upper thoracic UIV in patients with high preoperative C2–T9 PA may reduce PJK. Cite this article: Bone Joint J 2026;108-B(7):943–951.