Alan H. Daniels

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.: Systematic review and meta-analysis. Objective.: To compare outcomes between supine anterior lumbar interbody fusion (ALIF) and lateral decubitus oblique lumbar interbody fusion (OLIF). Background.: ALIF and OLIF differ in surgical corridor and patient positioning, with their relative advantages remaining debated. Methods.: A PRISMA-compliant search of PubMed, Embase, and Google Scholar was performed through April 2026 for studies evaluating anterior versus oblique lumbar interbody fusion. Outcomes included perioperative, complication, patient-reported, and sagittal alignment measures, pooled using fixed- or random-effects models based on heterogeneity (I²>50%). Results.: Thirteen studies (1,432 patients; 795 ALIF, 637 OLIF) met inclusion criteria. OLIF was associated with shorter length of stay (−0.87 days [ 95% CI: −1.47 to −0.26], P =0.005). Leave-one-out analyses demonstrated lower operative time (−39.07 minutes [95% CI: −76.73 to −1.41], P =0.04) and estimated blood loss (−96.32 mL [95% CI: −182.03 to −10.61], P =0.03) favoring OLIF, though substantial heterogeneity persisted. Complications and patient-reported outcomes did not differ. OLIF showed greater reductions in sagittal vertical axis (SVA) immediately postoperatively (−18.32 mm [95% CI: −30.89 to −5.75], P =0.004) and at final follow-up (−9.39 mm [95% CI: −17.83 to −0.96], P =0.03). In a subanalysis of fusions involving the sacrum, OLIF had lower EBL (−182.32 mL [95% CI: −297.38 to −67.27], P =0.002) and shorter LOS (−1.45 days [95% CI: −1.72 to −1.18], P P =0.06). Conclusions.: OLIF appears to offer a modest advantage over ALIF, with shorter hospitalization, comparable complications and patient-reported outcomes, and greater SVA correction. These perioperative benefits could potentially be meaningful in patients with higher comorbidity burden and appeared preserved in fusions involving the sacrum. The SVA correction may reflect advantages of single-position lateral surgery for restoring global alignment. Level of Evidence.: III

➢ Cervical sagittal alignment is associated with patient-reported outcomes, with higher T1 slope-cervical lordosis mismatch and greater C2-C7 sagittal vertical axis correlating with greater disability and worse health-related quality of life. ➢ Cervical alignment must be interpreted alongside global sagittal balance, as cervical posture interacts with thoracic and spinopelvic alignment and compensatory mechanisms. ➢ Both anterior and posterior cervical fusion can influence sagittal alignment, but optimal outcomes depend on alignment-conscious planning tailored to deformity morphology and spinal flexibility. ➢ Preserving or restoring physiologic cervical alignment reduces the risk of postoperative imbalance and adjacent-segment disease, supporting alignment-guided surgical decision-making.

Study Design: Narrative review. Objectives: To synthesize current evidence on the epidemiology, pathophysiology, classification, evaluation, and imaging of cervical spine injuries (CSI) in athletes and propose a practical framework for return-to-sport (RTS) decision-making. Methods: A review of the most recent and relevant published studies and consensus statements was performed, focusing on athletic cervical spine pathology. Key domains included on-field assessment, imaging modalities, clinical clearance criteria, and sport-specific risk considerations. All literature published in reputable journals, preferably available through well-regarded databases such as Scopus and PubMed, was eligible for inclusion, with preference given to the most recent publications related to any given topic. Results: The reviewed literature supports that RTS across CSI types requires resolution of symptoms, normal neurologic examination, restoration of painless cervical range of motion and strength, and radiographic evidence of healing or stability. MRI is consistently recommended for identifying high-risk features such as canal stenosis, cord signal change, or ligamentous disruption. Sport-specific risk stratification is supported by data showing higher reinjury rates in collision sports. Evidence remains heterogeneous, with substantial variation in specialist recommendations. Conclusions: Safe RTS after CSI requires comprehensive clinical and imaging assessment, recognition of sport-specific risks, and shared decision-making to prioritize athlete safety while avoiding unnecessary restrictions.

Background/Objectives: Chlorhexidine and iodine-based preparations are both widely used, and the existing literature suggests a possible advantage of chlorhexidine in clean elective surgery. Whether this extends to instrumented degenerative spine surgery is unknown. We asked whether chlorhexidine-based skin preparation reduces 90-day postoperative infection compared with iodine-based preparation after instrumented degenerative cervical or lumbar spine surgery. Methods: A retrospective TriNetX cohort study was performed among adults undergoing instrumented degenerative cervical or lumbar spine surgery. Patients were stratified by anatomic region and by preoperative preparation exposure: chlorhexidine-based versus iodine-based. Moreover, 1:1 propensity-score matching was performed within each anatomic stratum on demographics, Charlson Comorbidity Index (CCI), diabetes, smoking, obesity and BMI, immunosuppression, methicillin-resistant Staphylococcus aureus (MRSA) carrier status, and index procedure codes. The primary outcome was 90-day postoperative infection. Secondary outcomes were superficial and deep surgical site infection, MRSA infection, incision and drainage, debridement, sepsis, urinary tract infection, and pneumonia. Results: After matching, the cervical cohort included 3528 patients per group and the lumbar cohort 4164 per group. Postoperative infection did not differ in the cervical cohort (1.76% vs. 1.59%; risk ratio [RR] 1.11, 95% confidence interval [CI] 0.77–1.58; p = 0.578) or the lumbar cohort (3.17% vs. 3.29%; RR 0.96, 95% CI 0.76–1.22; p = 0.757). Superficial and deep infection, MRSA infection, debridement, sepsis, urinary tract infection, and pneumonia did not differ significantly in either cohort. Conclusions: No statistically significant difference in 90-day postoperative infection was found between chlorhexidine-based and iodine-based skin preparation after instrumented degenerative cervical or lumbar spine surgery.

Study Design.: Retrospective cohort. Objective.: To evaluate the associations of 28 preoperative comorbidities with all-cause and etiology-specific revisions (pseudarthrosis, mechanical failure, adjacent segment disease [ASD], infection) following single-level degenerative spinal fusion. Summary of Background Data.: Revision following spinal fusion for degenerative spinal disease remains frequent and costly. While technical factors are well studied, the extent to which preoperative comorbidities differentially predispose to specific revision etiologies is unclear. Materials and Methods.: Using the PearlDiver Mariner170 claims database (2010–2023), we identified adults undergoing single-level degenerative spinal fusion and followed them for 2 years for reoperation. All-cause and etiology-specific revisions were defined by CPT/ICD codes. Preoperative comorbidities were analyzed using multivariable cox proportional hazards models adjusted for age, sex, and all comorbidities. Bonferroni correction set significance at P ≤0.00036. Results.: Among 399,186 patients (mean age 59.7±13.0; 56.7% female; mean CCI 1.4±1.2), anaemia (HR 1.33), osteoporosis (HR 1.31), substance-related disorders (HR 1.25), and depression (HR 1.19) conferred the greatest risk of all-cause revision. Type 2 diabetes (HR 1.07) and essential hypertension (HR 1.14) had smaller but significant effects. Etiology-specific analyses showed that osteoporosis, anaemia, depression, and substance-related disorders were consistently associated with increased risk across pseudarthrosis, mechanical failure, and ASD. Mechanical failure was additionally associated with hypertension (HR 1.20) and diabetes (HR 1.28), which were not significant in the other revision subtypes. In contrast, ASD revisions were uniquely associated with osteoarthritis (HR 1.26). No comorbidity was significantly associated with infection-related revision. All hazard ratios were significant at P <0.001 unless otherwise specified. Conclusion.: In this national cohort of patients, osteoporosis, anaemia, depression, and substance-related disorders emerged as significant predictors of non-infectious revision within two years. Hypertension and type 2 diabetes conferred more modest risks for mechanical failure. These findings support the integration of comorbidity-informed risk stratification into preoperative planning and highlight the potential optimization to minimize revisions and enhance clinical outcomes.

Study Design.: Systematic review and meta-analysis. Objective.: To compare functional, radiographic, and complication outcomes among ACDF, PCDF, and laminoplasty for multilevel cervical spondylotic myelopathy (CSM). Summary of Background Data.: CSM is a major source of patient morbidity in the United States. Three surgical approaches are commonly employed for this degeneration: ACDF, PCDF, and laminoplasty. Comparative data is warranted to guide approach selection. Methods.: In accordance with PRISMA guidelines, PubMed, Embase, CENTRAL, and Scopus were searched through February 2026 to identify comparative studies reporting outcomes among adult patients undergoing ACDF, PCDF, or laminoplasty for multilevel (≥3 levels) CSM. Twelve studies comprising 1,129 patients met inclusion criteria and were organized into three pairwise comparisons: ACDF versus laminoplasty, PCDF versus laminoplasty, and ACDF versus PCDF. Functional, radiographic, and complication outcomes were comparatively assessed. Continuous outcomes were pooled as mean differences (MD) with 95% confidence intervals (CI). Dichotomous outcomes were pooled as odds ratios (OR) with 95% CI. Heterogeneity was assessed using the I² statistic. Results.: JOA score improvement did not differ between ACDF and laminoplasty (MD=−0.20, P =0.43) or ACDF and PCDF (MD=1.06, P =0.21). VAS neck pain favored ACDF over laminoplasty (MD=−1.05, P =0.03). ACDF demonstrated reduced cervical range of motion (MD=−9.14°, P P =0.002) and longer after PCDF (MD=1.19 days, P P =0.007) and C5 palsy (Peto OR=0.27, P =0.049) but higher rates of dysphagia (Peto OR=5.88, P P =0.01). Conclusions.: ACDF, PCDF, and laminoplasty demonstrated similar neurological recovery for multilevel CSM. Procedure-specific differences in cervical range of motion, length of stay, and complication profiles support approach selection guided by preoperative alignment and patient-specific concerns.