Faculty Bibliography

STUDY DESIGN/METHODS:Retrospective database study. OBJECTIVE:Compare the revision rates of 2-level ACDF, CDR, and hybrid ACDF/CDR. SUMMARY OF BACKGROUND DATA/BACKGROUND:While single-level CDR has been extensively studied, multilevel CDR and hybrid ACDF/CDR constructs have been less well studied. METHODS:This study utilized a large commercial insurance database of patients 65 years old or younger. Patients undergoing 2-level ACDF, 2-level CDR, and hybrid 2-level ACDF/CDR were identified. Patients age 18 years or older with malignant, infectious, or neoplastic etiologies were excluded, as were those undergoing revision surgery or any concomitant posterior cervical surgery. Study follow-up was terminated at 5 years postoperatively. The primary outcome was revision surgery, including anterior and posterior decompression, fusion, and arthroplasty. RESULTS:A total of 99,282 patients were included. The mean age was 51.3 years old (SD 8.1). The mean maximum follow-up was 2.1 years (SD 1.7). In all 3.2% (n=3197) underwent 2-level CDR, 0.5% (n=448) underwent hybrid 2-level ACDF/CDR, and 96.3% (n=95,637) underwent 2-level ACDF. At 5 years postoperatively, in Kaplan-Meier analysis, revision occurred in 10.0% of the CDR group, 12.4% of the hybrid group, and 10.0% of the ACDF group. In multivariable regression analysis, no significant differences in revision occurrence were observed between the CDR, hybrid, and ACDF groups (P<0.15 for all comparisons). In multivariable regression analysis stratified by plate versus stand-alone cage, patients with plated hybrid constructs had higher revision rates than those with both plated ACDF constructs (HR: 1.5, P=0.0387) and 2-level CDR (HR: 1.5, P=0.0477). CONCLUSIONS:In this retrospective database study of patients 65 years old or younger undergoing 2-level anterior cervical surgery, there were no significant differences at 5-year follow-up in revision rates for patients undergoing 2-level CDR, 2-level ACDF, and hybrid ACDF/CDR surgeries. In subanalysis, patients specifically with a plated hybrid ACDF/CDR had a higher occurrence of revision versus those undergoing plated 2-level ACDF or 2-level CDR. Future multicenter, prospective research is necessary to further assess these findings.

OBJECTIVE:This study aimed to characterize international practice patterns in the surgical management of primary lumbar disc herniation (LDH) among AO Spine surgeons. METHODS:A cross-sectional online survey was distributed in September 2024 to AO Spine members. The questionnaire collected detailed information on demographic characteristics, surgical indications, preferred techniques, and approaches for primary LDH treatment. Data on specialty, practice setting, fellowship training, and surgical case volume were analyzed using univariate and multivariate logistic regression to identify significant associations between surgeon characteristics and treatment preferences. RESULTS:A total of 714 surgeons participated, representing diverse regions: North America (9.0%), Latin America (18.7%), Europe & Southern Africa (34.7%), Middle East & Northern Africa (12.8%), and Asia Pacific (24.8%). Neurological status was the most critical factor influencing early operative treatment in nonurgent cases, while bladder/bowel dysfunction and severe motor deficits were the primary indications in urgent scenarios. The majority of respondents (54.2%) preferred a mini-open technique-using either a surgical microscope or loupes-with partial laminotomy (58.1%) and partial discectomy (63.2%) being the most frequently performed procedures. Regional variations and differences in surgeon training were significantly associated with the choice of surgical approach and overall case volume. CONCLUSION/CONCLUSIONS:The findings reveal substantial variability in the surgical management of primary LDH across regions and specialties. This comprehensive dataset underscores the need for standardized, evidence-based guidelines to harmonize treatment strategies and optimize patient outcomes.

OBJECTIVE:Lumbar discectomy is one of the most frequently undertaken procedures for the management of lumbar disc herniation. However, it may be complicated by recurrent disc herniation, with reported rates as high as 25%. To the authors' knowledge, this study is the largest systematic review to date, analyzing the clinical and radiographic risk factors for recurrent disc herniation. METHODS:A systematic literature search of Embase and PubMed/Medline, covering the period from inception to October 1, 2025, was conducted to identify case-control or cohort studies reporting risk factors for recurrent disc herniation. Risk factors were classified into baseline, clinical, and radiographic risk factors. Meta-analysis was performed for any reported risk factor with data from 3 or more studies. The assessment included an evaluation of publication bias and heterogeneity. RESULTS:A total of 51 studies published during the search timeframe, comprising 52,479 patients, met the inclusion criteria. Recurrent disc herniation occurred in 6,794 patients (12.9%). Significant risk factors for disc herniation included high body mass index (BMI) (standard mean difference [SMD], 0.48; 95% confidence interval [CI], 0.26-0.70), diabetes (odds ratio [OR], 1.48; 95% CI, 1.23-1.77), increased sagittal range of motion (SMD, 2.15; 95% CI, 0.35-3.94), and Modic changes (OR, 2.97; 95% CI, 2.20-4.01). No other significant predictors for recurrent disc herniation were identified. CONCLUSION/CONCLUSIONS:In conclusion, patients with high BMI, diabetics, increased sagittal range of motion, and presence of Modic changes are at increased risk of recurrent disc herniation. Future prospective studies are needed to validate the risk factors identified in this study associated with recurrent disc herniation.

Low back pain is a leading cause of disability worldwide, with intervertebral disc herniation contributing substantially to its burden. Most patients improve with conservative care, often associated with disc resorption. Although increasingly recognized as a major determinant of recovery, the mechanisms underlying resorption remain poorly understood. Herniated disc tissue induces immune cell infiltration and release of cytokines and proteolytic enzymes, yet standard anti-inflammatory treatments may paradoxically impede this process. Outcomes are also influenced by physical therapy, lifestyle, herniation characteristics, and immunological background, but predictive biomarkers are lacking. This review summarizes the current knowledge gap and explores strategies to harness intrinsic healing for personalized management.

OBJECTIVE:Bracing after lumbar discectomy surgery (LDS) is a controversial topic with paucity of related scientific literature. Previous surveys on spine surgeons' preferences were limited both in geographical coverage and number of respondents. The aim of this study is to fill this gap in the literature. METHODS:An international online survey among AO Spine members regarding the postoperative recommendations for bracing (PoBr), activity restriction (AR), and associated factors, was performed. RESULTS:A total of 703 spine surgeons participated in the survey of which 34% recommended PoBr, with half of them reported usage for 4 weeks. Main influencing variables were being from Europe/South Africa region, greater extent of bony decompression, and larger amount of excised disc material. Seventy-nine percent of the respondents recommended postoperative AR. Prolonged standing, prolonged sitting, and driving were usually restricted for 2 weeks. Bending, twisting, lifting, and low-intensity physical activities for 3 months, while high-intensity physical activities and direct contact sports for 6 months were restricted. CONCLUSION/CONCLUSIONS:Despite recent literature insights showing limited evidence of efficacy, 34% and 80% of a large cohort of international surgeons practice bracing and recommend AR after LDS for variable durations. Extensive bony decompression and radical discectomy significantly influenced the decision to brace, similarly endoscopic approaches and radical discectomy influenced the decision to restrict activity. These findings emphasize the persistent evidence-practice gap and the wide variability on the global level. More randomized controlled trials are warranted on this topic to reach an evidence-based recommendation.

BACKGROUND:Enhanced Recovery After Surgery (ERAS) protocols aim to improve recovery, reduce complications, and optimise surgical outcomes. Despite increasing use in spinal surgery, no standardised ERAS for spinal surgery (ERASS) exists and evidence synthesis is limited. This umbrella review consolidates findings from systematic reviews (SRs) and meta-analyses (MAs) to evaluate the clinical and economic impact of ERASS and identify research gaps. METHODS:A systematic search of MEDLINE, Embase, Cochrane Database of Systematic Reviews, and Web of Science (1990-2024) identified SRs and MAs on ERASS. Data extraction followed Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) and Preferred Reporting Items for Overviews of Reviews (PRIOR), with quality assessed using AMSTAR-2 and ROBIS. Overlapping primary studies were removed before recalculating pooled estimates using fixed or random-effects models based on heterogeneity. Primary outcomes included length of stay, postoperative complications, readmission rates, healthcare costs, pain scores, and opioid consumption. RESULTS:Seventeen SRs and 55 MAs (319 primary studies; n=221 605 participants) were included. ERASS significantly reduced length of stay (-1.55 days; 95% confidence interval [CI] -1.83 to -1.27 days; P<0.01), postoperative complications (relative risk=0.61; 95% CI 0.52-0.72; P<0.01), opioid consumption (-7.26 mg morphine equivalents; 95% CI -10.82 to -3.70 mg; P<0.01), and healthcare costs (-$1029.41 per patient; 95% CI -$1630.17 to -$428.65; P<0.01). Readmission rates were not significantly impacted (relative risk=0.91; P=0.38). Pain scores showed a modest, non-significant reduction (-0.27; 95% CI -0.66 to 0.13; P=0.19). High heterogeneity was observed, reflecting protocol and design variation. CONCLUSIONS:ERASS protocols significantly improve surgical efficiency and safety. Standardised guidelines and future research addressing heterogeneity, under-represented ERASS elements, and long-term outcomes are needed. SYSTEMATIC REVIEW PROTOCOL/UNASSIGNED:PROSPERO (CRD42024578786).

BACKGROUND/UNASSIGNED:Interbody fusion has been performed for many decades with evolving strategies and approaches to improve safety, fusion rates, and clinical outcomes. There have been ongoing advancements in the understanding of spinal biomechanics driving improved implant designs. The advent of 3D printing has allowed new concepts of cage designs to become a reality. The purpose of this narrative review is to provide an overview of current and developing technologies in the area of fusion cage design as well as concerns of the impact of marketing versus science in this area. METHODS/UNASSIGNED:A literature search was conducted on PubMed and OVID to identify articles related to interbody fusion cage design. The focus of the review was on current and future interbody fusion cage design. RESULTS/UNASSIGNED:The area of fusion cage design has been rapidly growing. The greatest advancements have been in the area of additive manufacturing which has allowed for much more intricate implant design. Significant advancements have also been made in improving the surfaces of implants to promote osseointegration. Advancements in materials, manufacturing, and sensor technologies are paving the way for developing intelligent interbody fusion cages capable of monitoring fusion progression and potentially stimulating bone growth. CONCLUSION/UNASSIGNED:There have been many exciting developments in the area of fusion cages, primarily related to materials, design, and surface topology, much of which have been driven by the advent of 3D printing. While many of these technologies may hold promise, there is relatively little data for the particular purported benefits of these implants. Much work is needed to understand the mechanobiological function of these devices, their clinical outcomes, indications, and cost-effectiveness.